This study presents a comprehensive digital mosaic of ice motion across Antarctica assembled from satellite radar data. The data reveal widespread, patterned, enhanced flow of tributary glaciers reaching hundreds to thousands of kilometers inland over the entire continent. This emphasizes the importance of basal-slip dominated tributary flow over deformation-dominated ice sheet flow, redefining our understanding of ice sheet dynamics. The extensive network of fast-flowing tributaries challenges prior views of ice sheet flow and implies a tighter connection between coastal and interior ice flow than previously thought.
The document examines the dynamics, extent, and timing of the British Ice Sheet during the Last Glacial Maximum through analysis of glacial landforms and dated sites in northern England. Key findings include:
1) The ice sheet was heterogeneous, reaching its maximum extent at different times in different areas. It advanced slowly from ice fields in upland areas before filling valleys.
2) Dynamics varied throughout growth and retreat. During growth, ice flowed radially from centers; during retreat, regional dispersal centers dominated.
3) Analysis of landforms showed complex and changing flow patterns, with ice reaching its maximum approximately 27,000 years ago before retreating rapidly across waterways by 15,000 years ago.
CLIMATE CHANGE IMPACT ASSESSMENT ON MELTING GLACIERS USING RS & GISAbhiram Kanigolla
Remote sensing and GIS techniques are effective methods for mapping and monitoring glaciers and the impacts of climate change. Two case studies are summarized in the document. The first case study monitors the Gangotri glacier in India using satellite imagery and finds a 6% reduction in glacier area between 1962 and 2006. The second case study analyzes satellite images of Mount Suphan glacier in Turkey and determines that the glacier area decreased from 1.2 km2 to 0.33 km2 between 1977 and 2000, with climatic factors like increasing minimum temperatures contributing to the recession.
Modification and Climate Change Analysis of surrounding Environment using Rem...iosrjce
This document discusses the application of remote sensing (RS) and geographic information systems (GIS) in analyzing climate change and the surrounding environment. It begins by defining key terms related to climate, climate change, and RS and GIS. It then highlights several areas where RS and GIS have been applied, including glacier monitoring, vegetation change monitoring, and carbon trace/accounting. Studies are discussed that use RS and GIS to monitor glacier retreat, snow depth, land cover change, and above-ground carbon stocks. The document concludes that RS and GIS play a crucial role in understanding and managing climate change by providing important spatial data and enabling the monitoring of environmental changes over time.
Simulated versus Satellite Retrieval Distribution Patterns of the Snow Water ...Agriculture Journal IJOEAR
Abstract— Snow is a very important component of the climate system which controls surface energy and water balances. Its high albedo, low thermal conductivity and properties of surface water storage impact regional to global climate. The various properties characterizing snow are highly variable and so have to be determined as dynamically active components of climate. However, on large spatial scales the properties of snow are not easily quantified either from numerical modelling or observations. Since neither observations (ground measurements or satellite retrievals) nor models alone are capable of providing enough adequate information about the time space variability of snow properties, it becomes necessary to combine their information. In the presented study the obtained with the regional climate model RegCM snow water equivalent (SWE) on monthly basis over Southeast Europe for a time window of 14 consecutive winters is compared with the Globsnow satellite product. The concordance between both datasets is evaluated with number of statistical scores. The result reveals the principal agreement between the two products, but however, with very significant discrepancies, mainly overestimations, for some years and gridcells.
This document summarizes ground temperature analysis from sites located across different ecotypes (vegetation classes) in western Alaska. Key findings include:
- The absence of near-surface permafrost corresponds to ecotypes lacking a moss layer.
- Factors like thawing and freezing N-Factors help explain differences in permafrost temperatures between ecotypes. For example, one white spruce site receives less heat in summer but loses less heat in winter than another.
- A preliminary map was created predicting mean annual ground temperature ranges based on translating the ecotype classifications. This map could help understand how permafrost may change under climate change.
Radar evidence of subglacial liquid water on MarsSérgio Sacani
The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.
1) Scientists discovered a massive subsurface ice layer beneath an area of intermittent melt pond formation on the Larsen C Ice Shelf in Antarctica.
2) The ice layer is at least 16 km across, several km long, and tens of meters deep. It consists of two units - an upper solid ice unit formed from refreezing of ponded water, and a lower infiltration ice unit formed from refreezing of meltwater that percolated into dense firn.
3) Analysis of borehole data, firn modeling, and satellite images indicates the ice layer formed in response to intense surface melting and pond formation between 2001-2009, and is likely warmer and denser than ice in areas without such melting
Hydrocarbon potential of the Borno Basin through Electrofacies and depositional environment analysis was carried out from well log and seismic reflection data to reassess the potential of the Basin thereby justifying the huge financial commitment of the Government. The reflection configuration pattern from the seismic reflection lines is characterized by variation from parallel, continuous and strong amplitude to sub parallel, chaotic discontinuous and low amplitude which indicate a variation from a low energy basinal setting of uniform rate of continental deposition to high energy environment of monolithologic deposits. Furthermore, the derivable log signatures shows a variation from serrated mud/sand to serrated blocky to serrated funnel and bell shapes with depth. This imply a stable massive mud/sand rich basinwide environment to an upward regressive sequence of bar deposit followed by a deltaic estuarine clastic sediment to gradual upward transgressive decrease in grain size to a fluvial point bar deposit. These environments identified from the research are known to be hydrocarbon province.
The document examines the dynamics, extent, and timing of the British Ice Sheet during the Last Glacial Maximum through analysis of glacial landforms and dated sites in northern England. Key findings include:
1) The ice sheet was heterogeneous, reaching its maximum extent at different times in different areas. It advanced slowly from ice fields in upland areas before filling valleys.
2) Dynamics varied throughout growth and retreat. During growth, ice flowed radially from centers; during retreat, regional dispersal centers dominated.
3) Analysis of landforms showed complex and changing flow patterns, with ice reaching its maximum approximately 27,000 years ago before retreating rapidly across waterways by 15,000 years ago.
CLIMATE CHANGE IMPACT ASSESSMENT ON MELTING GLACIERS USING RS & GISAbhiram Kanigolla
Remote sensing and GIS techniques are effective methods for mapping and monitoring glaciers and the impacts of climate change. Two case studies are summarized in the document. The first case study monitors the Gangotri glacier in India using satellite imagery and finds a 6% reduction in glacier area between 1962 and 2006. The second case study analyzes satellite images of Mount Suphan glacier in Turkey and determines that the glacier area decreased from 1.2 km2 to 0.33 km2 between 1977 and 2000, with climatic factors like increasing minimum temperatures contributing to the recession.
Modification and Climate Change Analysis of surrounding Environment using Rem...iosrjce
This document discusses the application of remote sensing (RS) and geographic information systems (GIS) in analyzing climate change and the surrounding environment. It begins by defining key terms related to climate, climate change, and RS and GIS. It then highlights several areas where RS and GIS have been applied, including glacier monitoring, vegetation change monitoring, and carbon trace/accounting. Studies are discussed that use RS and GIS to monitor glacier retreat, snow depth, land cover change, and above-ground carbon stocks. The document concludes that RS and GIS play a crucial role in understanding and managing climate change by providing important spatial data and enabling the monitoring of environmental changes over time.
Simulated versus Satellite Retrieval Distribution Patterns of the Snow Water ...Agriculture Journal IJOEAR
Abstract— Snow is a very important component of the climate system which controls surface energy and water balances. Its high albedo, low thermal conductivity and properties of surface water storage impact regional to global climate. The various properties characterizing snow are highly variable and so have to be determined as dynamically active components of climate. However, on large spatial scales the properties of snow are not easily quantified either from numerical modelling or observations. Since neither observations (ground measurements or satellite retrievals) nor models alone are capable of providing enough adequate information about the time space variability of snow properties, it becomes necessary to combine their information. In the presented study the obtained with the regional climate model RegCM snow water equivalent (SWE) on monthly basis over Southeast Europe for a time window of 14 consecutive winters is compared with the Globsnow satellite product. The concordance between both datasets is evaluated with number of statistical scores. The result reveals the principal agreement between the two products, but however, with very significant discrepancies, mainly overestimations, for some years and gridcells.
This document summarizes ground temperature analysis from sites located across different ecotypes (vegetation classes) in western Alaska. Key findings include:
- The absence of near-surface permafrost corresponds to ecotypes lacking a moss layer.
- Factors like thawing and freezing N-Factors help explain differences in permafrost temperatures between ecotypes. For example, one white spruce site receives less heat in summer but loses less heat in winter than another.
- A preliminary map was created predicting mean annual ground temperature ranges based on translating the ecotype classifications. This map could help understand how permafrost may change under climate change.
Radar evidence of subglacial liquid water on MarsSérgio Sacani
The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.
1) Scientists discovered a massive subsurface ice layer beneath an area of intermittent melt pond formation on the Larsen C Ice Shelf in Antarctica.
2) The ice layer is at least 16 km across, several km long, and tens of meters deep. It consists of two units - an upper solid ice unit formed from refreezing of ponded water, and a lower infiltration ice unit formed from refreezing of meltwater that percolated into dense firn.
3) Analysis of borehole data, firn modeling, and satellite images indicates the ice layer formed in response to intense surface melting and pond formation between 2001-2009, and is likely warmer and denser than ice in areas without such melting
Hydrocarbon potential of the Borno Basin through Electrofacies and depositional environment analysis was carried out from well log and seismic reflection data to reassess the potential of the Basin thereby justifying the huge financial commitment of the Government. The reflection configuration pattern from the seismic reflection lines is characterized by variation from parallel, continuous and strong amplitude to sub parallel, chaotic discontinuous and low amplitude which indicate a variation from a low energy basinal setting of uniform rate of continental deposition to high energy environment of monolithologic deposits. Furthermore, the derivable log signatures shows a variation from serrated mud/sand to serrated blocky to serrated funnel and bell shapes with depth. This imply a stable massive mud/sand rich basinwide environment to an upward regressive sequence of bar deposit followed by a deltaic estuarine clastic sediment to gradual upward transgressive decrease in grain size to a fluvial point bar deposit. These environments identified from the research are known to be hydrocarbon province.
The document discusses coastal monitoring in Newfoundland and Labrador. It describes analyzing shoreline change in Point Verde using the Digital Shoreline Analysis System (DSAS). DSAS calculated that annual shoreline retreat ranges from 0.54 m/year to 0.15 m/year, indicating erosion of up to 12 m over the study period from 1993 to 2013. The document also outlines steps to display coastal monitoring data and shoreline change statistics on the Newfoundland and Labrador GeoScience Atlas to provide public access to the information.
Glaciations in response_to_climate_variations_preconditioned_by_evolving_topo...Sérgio Sacani
This document summarizes a study that used numerical modeling to examine how the topographic distribution (hypsometry) of landscapes influences glacial extent in response to climate variations. The key findings are:
1) In landscapes without prior glaciation, there is a nearly linear relationship between climate and glacial area.
2) In previously glaciated landscapes with hypsometric maxima below the snowline, highly nonlinear and rapid glacial expansions occur with minimal climate forcing when the snowline reaches the hypsometric maximum.
3) Glaciations before 950,000 years ago likely preconditioned landscapes in Europe and North America, producing landforms and hypsometric distributions that led to more extensive
Using receiver function analysis of seismic data recorded by 45 broadband seismometers on Streymoy Island, Faroe Islands, we estimate:
1) The depth of the converting boundary beneath the Faroe Islands is between 29-32 km, which represents conversion from a region of high-velocity lower crust rather than the crust-mantle boundary.
2) Forward modeling suggests this high-velocity lower crust is at least 6 km thick.
3) The thick high-velocity lower crust is interpreted to result from intrusion of magma into the pre-existing continental crust during continental breakup, rather than underplating of igneous material at the base of the crust.
1) The document describes a study applying poststack acoustic impedance inversion to characterize subsalt reservoirs using 3D seismic data from the Walker Ridge protraction area in the Gulf of Mexico.
2) Inversion of a depth-migrated seismic volume was able to derive relative acoustic impedance, which was then used with a background model to estimate absolute acoustic impedance.
3) Comparison of inverted acoustic impedance to well logs showed good agreement, indicating the potential for quantitative seismic analysis of subsalt reservoirs despite challenges of low frequencies and complex salt geometry.
The Impact of Seismic Facies Analysis on the Reservoir Architecture of “CHARL...IJSRED
The document analyzes the seismic facies of the "CHARLIE" field in the Niger Delta to understand its impact on reservoir architecture. Seven seismic facies units (Ai-Gi) were identified based on reflection attributes. Facies indicated environments ranging from fluvial-deltaic-beach and varying energy levels. The reservoir architecture is anticlinal and contains good source rock, seal, and reservoir potentials within the Akata-Agbada petroleum system. Seismic facies analysis helped interpret depositional environments, energy levels, lithology, and the field's petroleum play elements.
Qualitative Comparison of Offset Surfaces Between the Central and Eastern Gar...Tom Crane
This study analyzes and compares offset surfaces along the central and eastern segments of the Garlock fault in California using LiDAR data and imagery. Qualitative methods were used to establish relative ages of alluvial surfaces based on characteristics like height, shape, dissection, surface darkness, and smoothness. Measured offsets of surfaces of similar inferred ages along the central fault were greater than for the eastern fault, suggesting a reduction in slip rate eastward. Preliminary slip rate estimates are 4.2 mm/yr for the central fault and 1.0 mm/yr for the eastern fault, indicating a decreasing rate from west to east along the fault. OSL dating of samples will provide firmer slip rate calculations to verify
This 3D seismic survey was conducted over a coal mine reserve area to better define a geologic structure that could adversely impact longwall mining. The survey revealed an abrupt change in coal seam elevation, or "roll", that trends south into the reserve area before turning southeast. It also identified a deeper geologic structure beneath the roll that seismic time-slice sections suggest is a paleochannel meandering in a similar direction to the roll. Integrating borehole and seismic data using computer modeling, 3D block diagrams were generated showing the steep slope on the west flank of the roll that gradually decreases as it turns southeast. The high-resolution 3D seismic data provided valuable subsurface information to mine engineers for longwall panel development planning
Delineation of Hydrocarbon Bearing Reservoirs from Surface Seismic and Well L...IOSR Journals
Hydrocarbon reservoir has been delineated and their boundaries mapped using direct indicators from 3-D seismic and well log data from an oil field in Nembe creek, Niger Delta region. Well log signatures were employed to identify hydrocarbon bearing sands. Well to seismic correlation revealed that these reservoirs tied with direct hydrocarbon indicators on the seismic section. The results of the interpreted well logs revealed that the hydrocarbon interval in the area occurs between 6450ft to 6533ft for well A, 6449ft to 6537ft for well B and 6629ft to 6704ft for well C; which were delineated using the resistivity, water saturation and gamma ray logs. Cross plot analysis was carried out to validate the sensitivity of the rock attributes to reservoir saturation condition. Analysis of the extracted seismic attribute slices revealed HD5000 as hydrocarbon bearing reservoir.
The surface of Pluto is more geologically diverse and dynamic than had been expected,
but the role of its tenuous atmosphere in shaping the landscape remains unclear. We
describe observations from the New Horizons spacecraft of regularly spaced, linear ridges
whose morphology, distribution, and orientation are consistent with being transverse
dunes. These are located close to mountainous regions and are orthogonal to nearby wind
streaks. We demonstrate that the wavelength of the dunes (~0.4 to 1 kilometer) is best
explained by the deposition of sand-sized (~200 to ~300 micrometer) particles of methane
ice in moderate winds (<10 meters per second). The undisturbed morphology of the dunes,
and relationships with the underlying convective glacial ice, imply that the dunes have
formed in the very recent geological past.
A large impact crater beneath Hiawatha Glacier in northwest GreenlandSérgio Sacani
We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact- related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron aster- oid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.
Multichannel analysis of surface waves Harish Parimi
Active and passive surface wave methods were used to image subsurface shear wave slowness at the Coyote Creek field site. Comparisons of slowness profiles from different methods showed generally good agreement, with most methods predicting larger near-surface slowness and smaller deep slowness compared to the reference model. Site amplification estimates based on the different slowness models were also generally similar. The blind interpretation experiment demonstrated that surface wave methods can provide robust shear wave velocity structures when multiple independent interpretations are considered.
18494_Guided Facies Modeling using 3D Seismic and WellRoy Cox
This document summarizes research using 3D seismic data and well logs to create more geologically realistic models of reservoir facies distributions. Seismic attribute images were interpreted to map fluvial depositional features like channels. These geomorphic objects were then used to guide facies modeling between wells. This "soft conditioning" approach produced models that better honored both well data and seismic trends compared to previous methods. It was applied to reservoirs in the BB oil field comprised of Miocene fluvial and coastal deposits. Seismic slices helped delineate multiple channel belts and a point bar complex that informed the final facies models.
3D Facies Modelling project using Petrel software. Msc Geology and Geophysics
Abstract
The Montserrat and Sant Llorenç del Munt fan-delta complexes were developed during the Eocene in the Ebro basin. The depositional stratigraphic record of these fan deltas has been described as a made up by a several transgressive and regressive composite sequences each made up by several fundamental sequences. Each sequence set is in turn composed by five main facies belts: proximal alluvial fan, distal alluvial fan, delta front, carbonates platforms and prodelta.
Using outcrop data from three composite sequences (Sant Vicenç, Vilomara and Manresa), a 3D facies model was built. The key sequential traces of the studied area georeferenced and digitalized on to photorealistic terrain models, were the hard data used as input to reconstruct the main surfaces, which are separating transgressive and regressive stacking patterns. Regarding the facies modelling has been achieved using a geostatistical algorithm in order to define the stacking trend and the interfingerings of adjacent facies belts, and five paleogeographyc maps to reproduce the paleogeometry of the facies belts within each system tract.
The final model has been checked, using a real cross section, and analysed in order to obtain information about the Delta Front facies which are the ones susceptible to be analogous of a reservoir. Attending to the results including eight probability maps of occurrence, the transgressive sequence set of Vilomara is the greatest accumulation of these facies explained by its agradational component.
High Resolution Seismic Reflections: Coal Mine FieldsAli Osman Öncel
- High-resolution seismic reflection data was collected near Harco, Illinois to map shallow coal seams and help predict areas of roof instability, low sulfur coal, and geologic disturbances prior to mining.
- The data helped locate several faults, channels, and facies changes affecting the Herrin (No. 6) and Springfield (No. 5) coal seams, which drill hole data alone could not adequately map, even with boreholes spaced 25 meters apart.
- Processing and interpretation of the seismic data, combined with drill hole information, was useful for safe and economical exploitation of the coal deposits by mapping the coal seams and detecting features that could impact mining operations.
Deprem Verilerinin H/V Oranının Mevsimsel Değişimi Ali Osman Öncel
H/V oranının zaman içinde değişimi konusu bana oldukça ilginç gelmişti ve bu tür bir çalışma yapıldı mı sorusunu netleştirmek için araştırma yaptım ve 2021 yılında bu konuda GJI gibi bir dergide yayınlanmış bir çalışma buldum. Bu çalışma oldukça iyi bir referans H/V çalışmaları için. Önemli referans düşünceler şöyle; 1) Mevsimsel olarak yağışa bağlı olarak yeraltı kaynaklarında ki azalma ve yükselmeye bağlı olarak H/V yükseliyor, 2) H/V pik değerleri kaya zemin üzerinde yaklaşık BİR (1) oranında seyreder ve PİK vermezken, kaya zeminden uzaklaşıldıkça zemin etkisi ile PİK değerleri değişir, 3) Deprem ve Gürültü sinyallerinden hesap edilen F(PİK) nerede ise sabitken, H/V oranları %10 değişir, 4) M6.8 büyüklüğünde meydana gelen bir deprem H/V değişimlerini etkiler.
Yapılan çalışmada kullanılan yaklaşım SESAME (2004) kriterlerine uygun olarak 1) 60 dakikalık veriler analizi, 2) 1000 günden fazla gözlem süresi 3) 10'dan fazla farklı zeminlerde istasyon 4) 60 dakikalık birbirinden ayrı verilerin analiz edilmesi. Oldukça emek yoğun bir çalışma
This document summarizes a study that used airborne gamma spectrometry (radiometrics) data to map soils over large areas in Central Queensland, Australia in a more cost-effective way than traditional soil surveys. In a trial area of 6,000 ha, the study achieved 55.6% accuracy in predicting lithology, 65% for soil order, and 29% for soil profile class using radiometrics data and conceptual models. The models were refined and applied to a larger 49,000 ha area, achieving 63% accuracy for lithology prediction and soil order. Radiometrics was found to be useful for identifying broad soil characteristics and lithological units over large areas.
This document discusses various geodetic remote sensing methods for estimating glacial mass balance, including altimetry, photogrammetry, and interferometric synthetic aperture radar (InSAR). It focuses on applications using the Geoscience Laser Altimeter System (GLAS) on ICESat, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and compares the advantages and limitations of different techniques. Satellite and airborne altimetry have proven most successful for monitoring elevation changes over time to estimate mass balance, though challenges remain regarding spatial and temporal resolution of data.
Glaciers are large, dense accumulations of snow and ice that form on land where snowfall exceeds melting over many years. They are distinct from sea ice and lake ice. Glaciers cover 10% of the world's land area and store the largest reservoir of fresh water on Earth. The scientific study of glaciers is called glaciology and involves understanding their relationships with climate, sea levels, and impacts on humans and the environment. Remote sensing techniques such as aerial photography, satellite imagery, and radar are powerful tools for monitoring and mapping glaciers, which are often located in remote areas. Different sensors can detect glacial features, measure glacier flow velocities, and help determine mass balances and snowmelt runoff.
Application of Satellite Geodesy in Environmental and Climate ChangesAlok Verma
Satellite geodesy uses satellites to measure the shape and gravity of Earth. Satellite techniques like altimetry, GPS, InSAR, and GRACE monitor environmental changes from ice sheet mass balance, coastal uplift, and ground deformation. Studies using these techniques show increases in ice melt from Greenland and Antarctica, contributing to rising sea levels. InSAR effectively monitors surface changes from fluid injection into reservoirs.
The document discusses coastal monitoring in Newfoundland and Labrador. It describes analyzing shoreline change in Point Verde using the Digital Shoreline Analysis System (DSAS). DSAS calculated that annual shoreline retreat ranges from 0.54 m/year to 0.15 m/year, indicating erosion of up to 12 m over the study period from 1993 to 2013. The document also outlines steps to display coastal monitoring data and shoreline change statistics on the Newfoundland and Labrador GeoScience Atlas to provide public access to the information.
Glaciations in response_to_climate_variations_preconditioned_by_evolving_topo...Sérgio Sacani
This document summarizes a study that used numerical modeling to examine how the topographic distribution (hypsometry) of landscapes influences glacial extent in response to climate variations. The key findings are:
1) In landscapes without prior glaciation, there is a nearly linear relationship between climate and glacial area.
2) In previously glaciated landscapes with hypsometric maxima below the snowline, highly nonlinear and rapid glacial expansions occur with minimal climate forcing when the snowline reaches the hypsometric maximum.
3) Glaciations before 950,000 years ago likely preconditioned landscapes in Europe and North America, producing landforms and hypsometric distributions that led to more extensive
Using receiver function analysis of seismic data recorded by 45 broadband seismometers on Streymoy Island, Faroe Islands, we estimate:
1) The depth of the converting boundary beneath the Faroe Islands is between 29-32 km, which represents conversion from a region of high-velocity lower crust rather than the crust-mantle boundary.
2) Forward modeling suggests this high-velocity lower crust is at least 6 km thick.
3) The thick high-velocity lower crust is interpreted to result from intrusion of magma into the pre-existing continental crust during continental breakup, rather than underplating of igneous material at the base of the crust.
1) The document describes a study applying poststack acoustic impedance inversion to characterize subsalt reservoirs using 3D seismic data from the Walker Ridge protraction area in the Gulf of Mexico.
2) Inversion of a depth-migrated seismic volume was able to derive relative acoustic impedance, which was then used with a background model to estimate absolute acoustic impedance.
3) Comparison of inverted acoustic impedance to well logs showed good agreement, indicating the potential for quantitative seismic analysis of subsalt reservoirs despite challenges of low frequencies and complex salt geometry.
The Impact of Seismic Facies Analysis on the Reservoir Architecture of “CHARL...IJSRED
The document analyzes the seismic facies of the "CHARLIE" field in the Niger Delta to understand its impact on reservoir architecture. Seven seismic facies units (Ai-Gi) were identified based on reflection attributes. Facies indicated environments ranging from fluvial-deltaic-beach and varying energy levels. The reservoir architecture is anticlinal and contains good source rock, seal, and reservoir potentials within the Akata-Agbada petroleum system. Seismic facies analysis helped interpret depositional environments, energy levels, lithology, and the field's petroleum play elements.
Qualitative Comparison of Offset Surfaces Between the Central and Eastern Gar...Tom Crane
This study analyzes and compares offset surfaces along the central and eastern segments of the Garlock fault in California using LiDAR data and imagery. Qualitative methods were used to establish relative ages of alluvial surfaces based on characteristics like height, shape, dissection, surface darkness, and smoothness. Measured offsets of surfaces of similar inferred ages along the central fault were greater than for the eastern fault, suggesting a reduction in slip rate eastward. Preliminary slip rate estimates are 4.2 mm/yr for the central fault and 1.0 mm/yr for the eastern fault, indicating a decreasing rate from west to east along the fault. OSL dating of samples will provide firmer slip rate calculations to verify
This 3D seismic survey was conducted over a coal mine reserve area to better define a geologic structure that could adversely impact longwall mining. The survey revealed an abrupt change in coal seam elevation, or "roll", that trends south into the reserve area before turning southeast. It also identified a deeper geologic structure beneath the roll that seismic time-slice sections suggest is a paleochannel meandering in a similar direction to the roll. Integrating borehole and seismic data using computer modeling, 3D block diagrams were generated showing the steep slope on the west flank of the roll that gradually decreases as it turns southeast. The high-resolution 3D seismic data provided valuable subsurface information to mine engineers for longwall panel development planning
Delineation of Hydrocarbon Bearing Reservoirs from Surface Seismic and Well L...IOSR Journals
Hydrocarbon reservoir has been delineated and their boundaries mapped using direct indicators from 3-D seismic and well log data from an oil field in Nembe creek, Niger Delta region. Well log signatures were employed to identify hydrocarbon bearing sands. Well to seismic correlation revealed that these reservoirs tied with direct hydrocarbon indicators on the seismic section. The results of the interpreted well logs revealed that the hydrocarbon interval in the area occurs between 6450ft to 6533ft for well A, 6449ft to 6537ft for well B and 6629ft to 6704ft for well C; which were delineated using the resistivity, water saturation and gamma ray logs. Cross plot analysis was carried out to validate the sensitivity of the rock attributes to reservoir saturation condition. Analysis of the extracted seismic attribute slices revealed HD5000 as hydrocarbon bearing reservoir.
The surface of Pluto is more geologically diverse and dynamic than had been expected,
but the role of its tenuous atmosphere in shaping the landscape remains unclear. We
describe observations from the New Horizons spacecraft of regularly spaced, linear ridges
whose morphology, distribution, and orientation are consistent with being transverse
dunes. These are located close to mountainous regions and are orthogonal to nearby wind
streaks. We demonstrate that the wavelength of the dunes (~0.4 to 1 kilometer) is best
explained by the deposition of sand-sized (~200 to ~300 micrometer) particles of methane
ice in moderate winds (<10 meters per second). The undisturbed morphology of the dunes,
and relationships with the underlying convective glacial ice, imply that the dunes have
formed in the very recent geological past.
A large impact crater beneath Hiawatha Glacier in northwest GreenlandSérgio Sacani
We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact- related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron aster- oid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.
Multichannel analysis of surface waves Harish Parimi
Active and passive surface wave methods were used to image subsurface shear wave slowness at the Coyote Creek field site. Comparisons of slowness profiles from different methods showed generally good agreement, with most methods predicting larger near-surface slowness and smaller deep slowness compared to the reference model. Site amplification estimates based on the different slowness models were also generally similar. The blind interpretation experiment demonstrated that surface wave methods can provide robust shear wave velocity structures when multiple independent interpretations are considered.
18494_Guided Facies Modeling using 3D Seismic and WellRoy Cox
This document summarizes research using 3D seismic data and well logs to create more geologically realistic models of reservoir facies distributions. Seismic attribute images were interpreted to map fluvial depositional features like channels. These geomorphic objects were then used to guide facies modeling between wells. This "soft conditioning" approach produced models that better honored both well data and seismic trends compared to previous methods. It was applied to reservoirs in the BB oil field comprised of Miocene fluvial and coastal deposits. Seismic slices helped delineate multiple channel belts and a point bar complex that informed the final facies models.
3D Facies Modelling project using Petrel software. Msc Geology and Geophysics
Abstract
The Montserrat and Sant Llorenç del Munt fan-delta complexes were developed during the Eocene in the Ebro basin. The depositional stratigraphic record of these fan deltas has been described as a made up by a several transgressive and regressive composite sequences each made up by several fundamental sequences. Each sequence set is in turn composed by five main facies belts: proximal alluvial fan, distal alluvial fan, delta front, carbonates platforms and prodelta.
Using outcrop data from three composite sequences (Sant Vicenç, Vilomara and Manresa), a 3D facies model was built. The key sequential traces of the studied area georeferenced and digitalized on to photorealistic terrain models, were the hard data used as input to reconstruct the main surfaces, which are separating transgressive and regressive stacking patterns. Regarding the facies modelling has been achieved using a geostatistical algorithm in order to define the stacking trend and the interfingerings of adjacent facies belts, and five paleogeographyc maps to reproduce the paleogeometry of the facies belts within each system tract.
The final model has been checked, using a real cross section, and analysed in order to obtain information about the Delta Front facies which are the ones susceptible to be analogous of a reservoir. Attending to the results including eight probability maps of occurrence, the transgressive sequence set of Vilomara is the greatest accumulation of these facies explained by its agradational component.
High Resolution Seismic Reflections: Coal Mine FieldsAli Osman Öncel
- High-resolution seismic reflection data was collected near Harco, Illinois to map shallow coal seams and help predict areas of roof instability, low sulfur coal, and geologic disturbances prior to mining.
- The data helped locate several faults, channels, and facies changes affecting the Herrin (No. 6) and Springfield (No. 5) coal seams, which drill hole data alone could not adequately map, even with boreholes spaced 25 meters apart.
- Processing and interpretation of the seismic data, combined with drill hole information, was useful for safe and economical exploitation of the coal deposits by mapping the coal seams and detecting features that could impact mining operations.
Deprem Verilerinin H/V Oranının Mevsimsel Değişimi Ali Osman Öncel
H/V oranının zaman içinde değişimi konusu bana oldukça ilginç gelmişti ve bu tür bir çalışma yapıldı mı sorusunu netleştirmek için araştırma yaptım ve 2021 yılında bu konuda GJI gibi bir dergide yayınlanmış bir çalışma buldum. Bu çalışma oldukça iyi bir referans H/V çalışmaları için. Önemli referans düşünceler şöyle; 1) Mevsimsel olarak yağışa bağlı olarak yeraltı kaynaklarında ki azalma ve yükselmeye bağlı olarak H/V yükseliyor, 2) H/V pik değerleri kaya zemin üzerinde yaklaşık BİR (1) oranında seyreder ve PİK vermezken, kaya zeminden uzaklaşıldıkça zemin etkisi ile PİK değerleri değişir, 3) Deprem ve Gürültü sinyallerinden hesap edilen F(PİK) nerede ise sabitken, H/V oranları %10 değişir, 4) M6.8 büyüklüğünde meydana gelen bir deprem H/V değişimlerini etkiler.
Yapılan çalışmada kullanılan yaklaşım SESAME (2004) kriterlerine uygun olarak 1) 60 dakikalık veriler analizi, 2) 1000 günden fazla gözlem süresi 3) 10'dan fazla farklı zeminlerde istasyon 4) 60 dakikalık birbirinden ayrı verilerin analiz edilmesi. Oldukça emek yoğun bir çalışma
This document summarizes a study that used airborne gamma spectrometry (radiometrics) data to map soils over large areas in Central Queensland, Australia in a more cost-effective way than traditional soil surveys. In a trial area of 6,000 ha, the study achieved 55.6% accuracy in predicting lithology, 65% for soil order, and 29% for soil profile class using radiometrics data and conceptual models. The models were refined and applied to a larger 49,000 ha area, achieving 63% accuracy for lithology prediction and soil order. Radiometrics was found to be useful for identifying broad soil characteristics and lithological units over large areas.
This document discusses various geodetic remote sensing methods for estimating glacial mass balance, including altimetry, photogrammetry, and interferometric synthetic aperture radar (InSAR). It focuses on applications using the Geoscience Laser Altimeter System (GLAS) on ICESat, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), and compares the advantages and limitations of different techniques. Satellite and airborne altimetry have proven most successful for monitoring elevation changes over time to estimate mass balance, though challenges remain regarding spatial and temporal resolution of data.
Glaciers are large, dense accumulations of snow and ice that form on land where snowfall exceeds melting over many years. They are distinct from sea ice and lake ice. Glaciers cover 10% of the world's land area and store the largest reservoir of fresh water on Earth. The scientific study of glaciers is called glaciology and involves understanding their relationships with climate, sea levels, and impacts on humans and the environment. Remote sensing techniques such as aerial photography, satellite imagery, and radar are powerful tools for monitoring and mapping glaciers, which are often located in remote areas. Different sensors can detect glacial features, measure glacier flow velocities, and help determine mass balances and snowmelt runoff.
Application of Satellite Geodesy in Environmental and Climate ChangesAlok Verma
Satellite geodesy uses satellites to measure the shape and gravity of Earth. Satellite techniques like altimetry, GPS, InSAR, and GRACE monitor environmental changes from ice sheet mass balance, coastal uplift, and ground deformation. Studies using these techniques show increases in ice melt from Greenland and Antarctica, contributing to rising sea levels. InSAR effectively monitors surface changes from fluid injection into reservoirs.
NISAR
Ice Sheets, Glaciers, and Oceans
NASA
National Aeronautics and Space Administration
NASA-ISRO Synthetic Aperture Radar (NISAR)
By
Dr. Pankaj Dhussa
The document discusses sensitivity studies conducted for the CoReH2O mission to analyze how snowpack parameters like grain size, layering, and melting state affect X-band and Ku-band radar backscatter. It summarizes modeling and experimental results showing grain size has a critical effect on backscatter and SWE retrieval, while density has little effect. Layering within the snowpack, including refrozen layers, can impact the relationship between backscatter and SWE.
Northern larsen ice shelf Antarctica: further retreat after collapseSimoneBoccuccia
This document discusses changes to glaciers and ice shelves in northern Larsen Ice Shelf, Antarctica after the collapse of parts of the ice shelf in 1995. It finds that large glaciers retreated several kilometers inland from their previous grounding lines after losing the back pressure from the ice shelves. Interferometry showed the main glacier in the area, Drygalski Glacier, accelerated its flow speed up to three times over 4 years after ice shelf collapse. Other grounded glaciers also saw accelerations, suggesting ice shelf collapse could contribute to sea level rise. The document also documents further retreat of Larsen B ice shelf through October 2000.
Differential interferometry of ALOS PALSAR data was used to monitor thickness changes of the Kangwure Glacier in the Himalayas between January 21 and March 8, 2010. The method provided high-accuracy measurement of thickness changes over a wide area, avoiding costly and labor-intensive in situ measurements. Results showed thinning of the glacier that agreed with historical data, demonstrating the potential of this InSAR method for long-term glacier monitoring. However, more data is still needed to fully validate the approach.
Paleofluvial mega canyon_beneath_the_central_greenland_ice_sheetSérgio Sacani
1) Researchers have discovered a 750-km long subglacial canyon beneath the central Greenland ice sheet using ice-penetrating radar data.
2) The canyon has a depth of up to 800 m and width of up to 10 km near the coast, and likely influenced basal water flow beneath the ice sheet over past glacial cycles.
3) Modeling of hydraulic potential suggests the canyon provided a pathway for subglacial water flow both before and during ice sheet formation, influencing the basal hydrology of northern Greenland.
Exposed subsurface ice sheets in the Martian mid-latitudesSérgio Sacani
Thick deposits cover broad regions of the Martian mid-latitudes with a smooth mantle; erosion
in these regions creates scarps that expose the internal structure of the mantle.We
investigated eight of these locations and found that they expose deposits of water ice that
can be >100 meters thick, extending downward from depths as shallow as 1 to 2 meters below
the surface.The scarps are actively retreating because of sublimation of the exposed water
ice.The ice deposits likely originated as snowfall during Mars’ high-obliquity periods and have
now compacted into massive, fractured, and layered ice.We expect the vertical structure of
Martian ice-rich deposits to preserve a record of ice deposition and past climate.
WE1.L09 - AN OVERVIEW OF THE DESDYNI MISSIONgrssieee
The DESDynI mission is an upcoming NASA/JPL satellite mission that will use L-band synthetic aperture radar (SAR) and multibeam lidar instruments to study ice sheet dynamics, ecosystems, carbon cycling, and natural hazards. The mission aims to launch in October 2017 for a 3-year mission. Key science goals include improving understanding of ice sheet behavior and sea level rise, measuring global forest biomass and carbon fluxes, and mapping earthquake and volcanic deformation. Airborne simulators like UAVSAR and LVIS are currently being used to develop and test DESDynI measurement techniques.
This document presents a study on glacial lake outburst floods (GLOFs) in the upper Kosi catchment region of Nepal. The objectives are to create land use/land cover maps, map glaciers and proglacial lakes from 1989, 2001, and 2010 using satellite imagery, and analyze the temporal variation and relationship between glaciers and proglacial lakes. Landsat, LISS-3, LISS-4, and Cartosat data will be used. The anticipated results are temporal variation in glaciers and proglacial lakes over the study period, and determining the relationship between proglacial lake formation and glacier shrinkage.
The proposed DESDynI mission aims to address key science questions about the dynamics of ice, deformation of the solid Earth, and changes to ecosystem structure. It would consist of an L-band radar operating in multiple modes, including polarimetric and repeat-pass interferometry, as well as a multi-beam profiling lidar. The instruments are designed to characterize ice sheet flow velocities to within 5 m/yr for fast ice and 1 m/yr for slow ice, measure surface deformation to better than 14 mm at 50 km scales, and estimate aboveground biomass to within 10 MgC/ha for biomass less than 40 MgC/ha. Frequent temporal sampling is needed to understand time-varying processes like earth
The document summarizes a study of sea ice characteristics in the southern region of the Okhotsk Sea using X-band and L-band SAR data. Ground truth data was collected from over 60 sampling points on Lake Saroma in February 2010. Backscattering characteristics were analyzed for TerraSAR-X and ALOS PALSAR data using a scattering model. TerraSAR-X data showed better correlation with ice thickness than PALSAR, especially for thin sea ice. Scattering decomposition of PALSAR data provided reasonable relationships with snow depth and surface roughness parameters.
1. The document discusses a project that uses very high resolution synthetic aperture radar (SAR) to map glacial lakes and monitor changes in glacial lake extent over time in order to assess glacial lake outburst flood (GLOF) hazards.
2. SAR is well-suited for this task because it has high spatial resolution of 2m and can acquire imagery regardless of weather or sunlight conditions with a repeat cycle of 11 days.
3. The project aims to classify imagery to identify water, ice, and other areas and deliver lake outlines and glacier outlines as GIS shapefiles for integration into user mapping systems.
Interannual and decadal variations of Antarctic ice shelves using multi-mission satellite radar altimetry, and links with oceanic and atmospheric forcings
WE2.L09 - Integrated SAR and lidar observations of the sea ice cover: Resolvi...grssieee
This document discusses using integrated synthetic aperture radar (SAR) and lidar observations to study sea ice thickness distribution by resolving the contributions of thermodynamics and dynamics. It presents the current observational capabilities of measuring ice motion with SAR and thickness with lidar. Future plans for the DESDynI mission are outlined, which would allow coordinated high-resolution observations of both ice motion and thickness over the Arctic Ocean every few days to better understand the underlying processes.
This study uses remote sensing and field methods to analyze the movement of two rock glaciers on Mount Mestas in southern Colorado over different timescales. Lichenometry of Rock Glacier 1 suggests an average flow rate of 17 cm/yr over the past 2000 years, while GPS and ground-based radar interferometry show slower present-day movement. Rock Glacier 2 demonstrates higher summer velocities of up to 1 cm/month. The preliminary results indicate temporal variability in movement over seasonal timescales as well as declining velocities during the Holocene for Rock Glacier 1.
The document discusses satellite radar altimeter measurements of elevation changes in the Larsen Ice Shelf between 1992 and 2001. It finds that the ice shelf lowered by up to 0.27 meters per year on average. This thinning is explained by increased summer meltwater and loss of basal ice through melting. Enhanced ocean-driven melting may provide a link between regional climate warming and the successive breakup of sections of the Larsen Ice Shelf. Testing rules out other potential causes of thinning like changes in sea level, ocean density, or surface accumulation. The long-term thinning observed suggests meltwater production alone does not account for the lowering, indicating additional thinning mechanisms are also involved.
Similar to Science 2011-rignot-science.1208336 (20)
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1−W2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ∼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ∼ 106M⊙ AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...Sérgio Sacani
We present the JWST discovery of SN 2023adsy, a transient object located in a host galaxy JADES-GS
+
53.13485
−
27.82088
with a host spectroscopic redshift of
2.903
±
0.007
. The transient was identified in deep James Webb Space Telescope (JWST)/NIRCam imaging from the JWST Advanced Deep Extragalactic Survey (JADES) program. Photometric and spectroscopic followup with NIRCam and NIRSpec, respectively, confirm the redshift and yield UV-NIR light-curve, NIR color, and spectroscopic information all consistent with a Type Ia classification. Despite its classification as a likely SN Ia, SN 2023adsy is both fairly red (
�
(
�
−
�
)
∼
0.9
) despite a host galaxy with low-extinction and has a high Ca II velocity (
19
,
000
±
2
,
000
km/s) compared to the general population of SNe Ia. While these characteristics are consistent with some Ca-rich SNe Ia, particularly SN 2016hnk, SN 2023adsy is intrinsically brighter than the low-
�
Ca-rich population. Although such an object is too red for any low-
�
cosmological sample, we apply a fiducial standardization approach to SN 2023adsy and find that the SN 2023adsy luminosity distance measurement is in excellent agreement (
≲
1
�
) with
Λ
CDM. Therefore unlike low-
�
Ca-rich SNe Ia, SN 2023adsy is standardizable and gives no indication that SN Ia standardized luminosities change significantly with redshift. A larger sample of distant SNe Ia is required to determine if SN Ia population characteristics at high-
�
truly diverge from their low-
�
counterparts, and to confirm that standardized luminosities nevertheless remain constant with redshift.
Evidence of Jet Activity from the Secondary Black Hole in the OJ 287 Binary S...Sérgio Sacani
Wereport the study of a huge optical intraday flare on 2021 November 12 at 2 a.m. UT in the blazar OJ287. In the binary black hole model, it is associated with an impact of the secondary black hole on the accretion disk of the primary. Our multifrequency observing campaign was set up to search for such a signature of the impact based on a prediction made 8 yr earlier. The first I-band results of the flare have already been reported by Kishore et al. (2024). Here we combine these data with our monitoring in the R-band. There is a big change in the R–I spectral index by 1.0 ±0.1 between the normal background and the flare, suggesting a new component of radiation. The polarization variation during the rise of the flare suggests the same. The limits on the source size place it most reasonably in the jet of the secondary BH. We then ask why we have not seen this phenomenon before. We show that OJ287 was never before observed with sufficient sensitivity on the night when the flare should have happened according to the binary model. We also study the probability that this flare is just an oversized example of intraday variability using the Krakow data set of intense monitoring between 2015 and 2023. We find that the occurrence of a flare of this size and rapidity is unlikely. In machine-readable Tables 1 and 2, we give the full orbit-linked historical light curve of OJ287 as well as the dense monitoring sample of Krakow.
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Sérgio Sacani
Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted Brγ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole SgrA* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual H−K and K−L colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and midinfrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of SgrA* are much shorter ( 2yr) than the epochs covered by the observations (≈15yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 ± 20◦, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of SgrA*. Alternatively, the gravitational influence of SgrA* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement. Key words. stars: black holes– stars: formation– Galaxy: center– galaxies: star formation
JAMES WEBB STUDY THE MASSIVE BLACK HOLE SEEDSSérgio Sacani
The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
Anti-Universe And Emergent Gravity and the Dark UniverseSérgio Sacani
Recent theoretical progress indicates that spacetime and gravity emerge together from the entanglement structure of an underlying microscopic theory. These ideas are best understood in Anti-de Sitter space, where they rely on the area law for entanglement entropy. The extension to de Sitter space requires taking into account the entropy and temperature associated with the cosmological horizon. Using insights from string theory, black hole physics and quantum information theory we argue that the positive dark energy leads to a thermal volume law contribution to the entropy that overtakes the area law precisely at the cosmological horizon. Due to the competition between area and volume law entanglement the microscopic de Sitter states do not thermalise at sub-Hubble scales: they exhibit memory effects in the form of an entropy displacement caused by matter. The emergent laws of gravity contain an additional ‘dark’ gravitational force describing the ‘elastic’ response due to the entropy displacement. We derive an estimate of the strength of this extra force in terms of the baryonic mass, Newton’s constant and the Hubble acceleration scale a0 = cH0, and provide evidence for the fact that this additional ‘dark gravity force’ explains the observed phenomena in galaxies and clusters currently attributed to dark matter.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Tr...Sérgio Sacani
Recent discoveries of Earth-sized planets transiting nearby M dwarfs have made it possible to characterize the
atmospheres of terrestrial planets via follow-up spectroscopic observations. However, the number of such planets
receiving low insolation is still small, limiting our ability to understand the diversity of the atmospheric
composition and climates of temperate terrestrial planets. We report the discovery of an Earth-sized planet
transiting the nearby (12 pc) inactive M3.0 dwarf Gliese 12 (TOI-6251) with an orbital period (Porb) of 12.76 days.
The planet, Gliese 12 b, was initially identified as a candidate with an ambiguous Porb from TESS data. We
confirmed the transit signal and Porb using ground-based photometry with MuSCAT2 and MuSCAT3, and
validated the planetary nature of the signal using high-resolution images from Gemini/NIRI and Keck/NIRC2 as
well as radial velocity (RV) measurements from the InfraRed Doppler instrument on the Subaru 8.2 m telescope
and from CARMENES on the CAHA 3.5 m telescope. X-ray observations with XMM-Newton showed the host
star is inactive, with an X-ray-to-bolometric luminosity ratio of log 5.7 L L X bol » - . Joint analysis of the light
curves and RV measurements revealed that Gliese 12 b has a radius of 0.96 ± 0.05 R⊕,a3σ mass upper limit of
3.9 M⊕, and an equilibrium temperature of 315 ± 6 K assuming zero albedo. The transmission spectroscopy metric
(TSM) value of Gliese 12 b is close to the TSM values of the TRAPPIST-1 planets, adding Gliese 12 b to the small
list of potentially terrestrial, temperate planets amenable to atmospheric characterization with JWST.
Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TES...Sérgio Sacani
We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a
bright (V = 12.6 mag, K = 7.8 mag) metal-poor M4V star only 12.162 ± 0.005 pc away from the Solar system with one of the
lowest stellar activity levels known for M-dwarfs. A planet candidate was detected by TESS based on only 3 transits in sectors
42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations
with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory,
as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of
12.76144 ± 0.00006 d and a radius of 1.0 ± 0.1 R⊕, resulting in an equilibrium temperature of ∼315 K. Gliese 12 b has excellent
future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar
compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool
stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy.
The importance of continents, oceans and plate tectonics for the evolution of...Sérgio Sacani
Within the uncertainties of involved astronomical and biological parameters, the Drake Equation
typically predicts that there should be many exoplanets in our galaxy hosting active, communicative
civilizations (ACCs). These optimistic calculations are however not supported by evidence, which is
often referred to as the Fermi Paradox. Here, we elaborate on this long-standing enigma by showing
the importance of planetary tectonic style for biological evolution. We summarize growing evidence
that a prolonged transition from Mesoproterozoic active single lid tectonics (1.6 to 1.0 Ga) to modern
plate tectonics occurred in the Neoproterozoic Era (1.0 to 0.541 Ga), which dramatically accelerated
emergence and evolution of complex species. We further suggest that both continents and oceans
are required for ACCs because early evolution of simple life must happen in water but late evolution
of advanced life capable of creating technology must happen on land. We resolve the Fermi Paradox
(1) by adding two additional terms to the Drake Equation: foc
(the fraction of habitable exoplanets
with significant continents and oceans) and fpt
(the fraction of habitable exoplanets with significant
continents and oceans that have had plate tectonics operating for at least 0.5 Ga); and (2) by
demonstrating that the product of foc
and fpt
is very small (< 0.00003–0.002). We propose that the lack
of evidence for ACCs reflects the scarcity of long-lived plate tectonics and/or continents and oceans on
exoplanets with primitive life.
A Giant Impact Origin for the First Subduction on EarthSérgio Sacani
Hadean zircons provide a potential record of Earth's earliest subduction 4.3 billion years ago. Itremains enigmatic how subduction could be initiated so soon after the presumably Moon‐forming giant impact(MGI). Earlier studies found an increase in Earth's core‐mantle boundary (CMB) temperature due to theaccumulation of the impactor's core, and our recent work shows Earth's lower mantle remains largely solid, withsome of the impactor's mantle potentially surviving as the large low‐shear velocity provinces (LLSVPs). Here,we show that a hot post‐impact CMB drives the initiation of strong mantle plumes that can induce subductioninitiation ∼200 Myr after the MGI. 2D and 3D thermomechanical computations show that a high CMBtemperature is the primary factor triggering early subduction, with enrichment of heat‐producing elements inLLSVPs as another potential factor. The models link the earliest subduction to the MGI with implications forunderstanding the diverse tectonic regimes of rocky planets.
Climate extremes likely to drive land mammal extinction during next supercont...Sérgio Sacani
Mammals have dominated Earth for approximately 55 Myr thanks to their
adaptations and resilience to warming and cooling during the Cenozoic. All
life will eventually perish in a runaway greenhouse once absorbed solar
radiation exceeds the emission of thermal radiation in several billions of
years. However, conditions rendering the Earth naturally inhospitable to
mammals may develop sooner because of long-term processes linked to
plate tectonics (short-term perturbations are not considered here). In
~250 Myr, all continents will converge to form Earth’s next supercontinent,
Pangea Ultima. A natural consequence of the creation and decay of Pangea
Ultima will be extremes in pCO2 due to changes in volcanic rifting and
outgassing. Here we show that increased pCO2, solar energy (F⨀;
approximately +2.5% W m−2 greater than today) and continentality (larger
range in temperatures away from the ocean) lead to increasing warming
hostile to mammalian life. We assess their impact on mammalian
physiological limits (dry bulb, wet bulb and Humidex heat stress indicators)
as well as a planetary habitability index. Given mammals’ continued survival,
predicted background pCO2 levels of 410–816 ppm combined with increased
F⨀ will probably lead to a climate tipping point and their mass extinction.
The results also highlight how global landmass configuration, pCO2 and F⨀
play a critical role in planetary habitability.
Constraints on Neutrino Natal Kicks from Black-Hole Binary VFTS 243Sérgio Sacani
The recently reported observation of VFTS 243 is the first example of a massive black-hole binary
system with negligible binary interaction following black-hole formation. The black-hole mass (≈10M⊙)
and near-circular orbit (e ≈ 0.02) of VFTS 243 suggest that the progenitor star experienced complete
collapse, with energy-momentum being lost predominantly through neutrinos. VFTS 243 enables us to
constrain the natal kick and neutrino-emission asymmetry during black-hole formation. At 68% confidence
level, the natal kick velocity (mass decrement) is ≲10 km=s (≲1.0M⊙), with a full probability distribution
that peaks when ≈0.3M⊙ were ejected, presumably in neutrinos, and the black hole experienced a natal
kick of 4 km=s. The neutrino-emission asymmetry is ≲4%, with best fit values of ∼0–0.2%. Such a small
neutrino natal kick accompanying black-hole formation is in agreement with theoretical predictions.
Detectability of Solar Panels as a TechnosignatureSérgio Sacani
In this work, we assess the potential detectability of solar panels made of silicon on an Earth-like
exoplanet as a potential technosignature. Silicon-based photovoltaic cells have high reflectance in the
UV-VIS and in the near-IR, within the wavelength range of a space-based flagship mission concept
like the Habitable Worlds Observatory (HWO). Assuming that only solar energy is used to provide
the 2022 human energy needs with a land cover of ∼ 2.4%, and projecting the future energy demand
assuming various growth-rate scenarios, we assess the detectability with an 8 m HWO-like telescope.
Assuming the most favorable viewing orientation, and focusing on the strong absorption edge in the
ultraviolet-to-visible (0.34 − 0.52 µm), we find that several 100s of hours of observation time is needed
to reach a SNR of 5 for an Earth-like planet around a Sun-like star at 10pc, even with a solar panel
coverage of ∼ 23% land coverage of a future Earth. We discuss the necessity of concepts like Kardeshev
Type I/II civilizations and Dyson spheres, which would aim to harness vast amounts of energy. Even
with much larger populations than today, the total energy use of human civilization would be orders of
magnitude below the threshold for causing direct thermal heating or reaching the scale of a Kardashev
Type I civilization. Any extraterrrestrial civilization that likewise achieves sustainable population
levels may also find a limit on its need to expand, which suggests that a galaxy-spanning civilization
as imagined in the Fermi paradox may not exist.
Best 20 SEO Techniques To Improve Website Visibility In SERPPixlogix Infotech
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HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
How to Interpret Trends in the Kalyan Rajdhani Mix Chart.pdfChart Kalyan
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GraphRAG for Life Science to increase LLM accuracyTomaz Bratanic
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TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
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HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Don’t worry, we can help with all of this!
We’ll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. We’ll provide examples and solutions for those as well. And naturally we’ll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
FREE A4 Cyber Security Awareness Posters-Social Engineering part 3Data Hops
Free A4 downloadable and printable Cyber Security, Social Engineering Safety and security Training Posters . Promote security awareness in the home or workplace. Lock them Out From training providers datahops.com
Skybuffer AI: Advanced Conversational and Generative AI Solution on SAP Busin...Tatiana Kojar
Skybuffer AI, built on the robust SAP Business Technology Platform (SAP BTP), is the latest and most advanced version of our AI development, reaffirming our commitment to delivering top-tier AI solutions. Skybuffer AI harnesses all the innovative capabilities of the SAP BTP in the AI domain, from Conversational AI to cutting-edge Generative AI and Retrieval-Augmented Generation (RAG). It also helps SAP customers safeguard their investments into SAP Conversational AI and ensure a seamless, one-click transition to SAP Business AI.
With Skybuffer AI, various AI models can be integrated into a single communication channel such as Microsoft Teams. This integration empowers business users with insights drawn from SAP backend systems, enterprise documents, and the expansive knowledge of Generative AI. And the best part of it is that it is all managed through our intuitive no-code Action Server interface, requiring no extensive coding knowledge and making the advanced AI accessible to more users.
Driving Business Innovation: Latest Generative AI Advancements & Success StorySafe Software
Are you ready to revolutionize how you handle data? Join us for a webinar where we’ll bring you up to speed with the latest advancements in Generative AI technology and discover how leveraging FME with tools from giants like Google Gemini, Amazon, and Microsoft OpenAI can supercharge your workflow efficiency.
During the hour, we’ll take you through:
Guest Speaker Segment with Hannah Barrington: Dive into the world of dynamic real estate marketing with Hannah, the Marketing Manager at Workspace Group. Hear firsthand how their team generates engaging descriptions for thousands of office units by integrating diverse data sources—from PDF floorplans to web pages—using FME transformers, like OpenAIVisionConnector and AnthropicVisionConnector. This use case will show you how GenAI can streamline content creation for marketing across the board.
Ollama Use Case: Learn how Scenario Specialist Dmitri Bagh has utilized Ollama within FME to input data, create custom models, and enhance security protocols. This segment will include demos to illustrate the full capabilities of FME in AI-driven processes.
Custom AI Models: Discover how to leverage FME to build personalized AI models using your data. Whether it’s populating a model with local data for added security or integrating public AI tools, find out how FME facilitates a versatile and secure approach to AI.
We’ll wrap up with a live Q&A session where you can engage with our experts on your specific use cases, and learn more about optimizing your data workflows with AI.
This webinar is ideal for professionals seeking to harness the power of AI within their data management systems while ensuring high levels of customization and security. Whether you're a novice or an expert, gain actionable insights and strategies to elevate your data processes. Join us to see how FME and AI can revolutionize how you work with data!
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/temporal-event-neural-networks-a-more-efficient-alternative-to-the-transformer-a-presentation-from-brainchip/
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Ivanti’s Patch Tuesday breakdown goes beyond patching your applications and brings you the intelligence and guidance needed to prioritize where to focus your attention first. Catch early analysis on our Ivanti blog, then join industry expert Chris Goettl for the Patch Tuesday Webinar Event. There we’ll do a deep dive into each of the bulletins and give guidance on the risks associated with the newly-identified vulnerabilities.
Have you ever been confused by the myriad of choices offered by AWS for hosting a website or an API?
Lambda, Elastic Beanstalk, Lightsail, Amplify, S3 (and more!) can each host websites + APIs. But which one should we choose?
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leewayhertz.com-AI in predictive maintenance Use cases technologies benefits ...alexjohnson7307
Predictive maintenance is a proactive approach that anticipates equipment failures before they happen. At the forefront of this innovative strategy is Artificial Intelligence (AI), which brings unprecedented precision and efficiency. AI in predictive maintenance is transforming industries by reducing downtime, minimizing costs, and enhancing productivity.
Let's Integrate MuleSoft RPA, COMPOSER, APM with AWS IDP along with Slackshyamraj55
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Azure API Management to expose backend services securely
Science 2011-rignot-science.1208336
1. Ice Flow of the Antarctic Ice Sheet
E. Rignot,1,2* J. Mouginot,1 B. Scheuchl1
1
Dept. Earth System Science, University of California Irvine, Irvine, CA, 92697 USA. 2Jet Propulsion Laboratory, California
Institute of Technology, Pasadena, CA 91109, USA.
*To whom correspondence should be addressed. E-mail: erignot@uci.edu
We present a reference, comprehensive, high-resolution, from topographic divides to a set of narrow, fast-moving
digital mosaic of ice motion in Antarctica assembled from glaciers that control most of the ice sheet discharge into the
multiple satellite interferometric synthetic-aperture radar ocean. This lack of broad-scale and detailed observation of
data acquired during the International Polar Year 2007- ice motion has placed a fundamental limit on the capability
2009. The data reveal widespread, patterned, enhanced and reliability of numerical models of ice sheet evolution (6).
Downloaded from www.sciencemag.org on August 25, 2011
flow with tributary glaciers reaching hundreds to On the eve of the international polar year, international
thousands of kilometers inland, over the entire continent. space agencies worked together to enable a complete InSAR
This view of ice sheet motion emphasizes the importance survey of Antarctica. Here, we employ spring 2009 data from
of basal-slip dominated tributary flow over deformation the Canadian Space Agency (CSA)'s and MacDonald,
dominated ice sheet flow, redefines our understanding of Dettwiler and Associates Ltd. (MDA)'s RADARSAT-2,
ice sheet dynamics, and has far-reaching implications for spring 2007-2008-2009 data from European Space Agency
the reconstruction and prediction of ice sheet evolution. (ESA)'s Envisat ASAR, and fall 2007-2008 data from the
Japan Aerospace Exploration Agency (JAXA)'s Advanced
Ice velocity is a fundamental characteristic of glaciers and ice
Land Observing Satellite (ALOS) PALSAR, complemented
sheets that measures the rate at which ice is transported from
by patches of CSA's RADARSAT-1 data from fall 2000 (7)
the interior regions toward the ocean, the location of preferred
and ESA's ERS-1/2 data from spring 1996 (2). Each radar
channels of ice transport, and how ice mass evolves with
instrument contributes its unique coverage and performance
time. Traditional measurements from ground-based stations
level (see Fig. S1 in supporting online material (SOM)).
are limited relative to the size of the continent, leading to an
The final mosaic assembles 900 satellite tracks and more
incomplete picture of Antarctica. Satellite radar
than 3,000 orbits of radar data (Fig. 1). The data are geo-
interferometry or InSAR has been successfully employed to
referenced with a precision better than one pixel, here 300 m,
map glacier flow independent of cloud cover, solar
to an Earth-fixed grid using a digital elevation model (DEM)
illumination or the presence of surface features (1). Until
(8). Absolute calibration of the surface velocity data relies on
now, however, the vast extent of East Antarctica, which
control points of zero motion distributed along the coast
comprises 77% of the continent, has been devoid of quality
(stagnant areas near ice domes or emergent mountains) and
data; only a few floating ice shelves have been mapped, and
along major ice divides (areas of zero surface slope in the
comprehensive velocity mapping has been limited to the
DEM) in a set of coast-to-coast ASAR tracks (fig. S1). The
lower reaches of key outlet glaciers (2).
mapping precision varies with instrument, location, technique
Balance velocity calculated from ice thickness, surface
of analysis, repeat cycle, time period and data stacking.
slope and snow accumulation data provides insights about the
Nominal errors range from 1 m/yr along major ice divides
potential flow pattern of the ice sheet (3), but the technique
with high data stacking to about 17 m/yr in areas affected by
assumes an ice sheet in mass equilibrium, which is not correct
ionospheric perturbations (fig. S2). In terms of strain rate, or
everywhere, and that ice flows perpendicular to surface
changes in velocity per unit length, data noise is at the 3 x
contours, which is a simplification of the gravitational driving
10−4 /yr level, which is sufficient to reveal effective strain
stress equation of motion (4). The precision of balance
rates along tributary shear margins over the vast majority of
velocity is affected by uncertainties in snow accumulation,
the continent (Fig. 2A).
major gaps in ice thickness data, and poor topographic
Ice velocity ranges from a few cm/yr near divides to a few
coverage near the South Pole. Nor does the technique apply
km/yr on fast moving glaciers and floating ice shelves, or 5
to floating ice shelves or replicate the correct width and
orders of magnitude. The histogram in surface velocity has a
extent of ice streams and tributaries (5). As a result, there is
bi-modal distribution with a main peak at 4-5 m/yr
no clear picture of ice sheet motion at the continental scale,
/ www.sciencexpress.org / 18 August 2011 / Page 1 / 10.1126/science.1208336
2. corresponding to slow motion in East Antarctica, and a suggests uncertainties in DEM-derived ice divide or recent
second peak at 250 m/yr driven by the fast flow of glaciers changes in ice dynamics and enhanced flow to the West. The
and ice shelves. The fastest glaciers, Pine Island and western tributary of Foundation Ice Stream offers a natural
Thwaites, are several times faster than any other glacier, and division between east and west Antarctica flow that was not
unique in terms of how far inland fast flow prevails. This is known before. Academy Glacier, a major eastern tributary of
indeed the sector of most rapid change at present, over the Foundation, extends to the West over the South Pole and to
widest area, and with the greatest impact on total ice sheet the East in parallel to Support-Force Ice Stream for more than
mass balance (2). Other fastest-moving glaciers include the 400 km, which is counter to the traditional view of well-
Larsen B glaciers in the Peninsula, which accelerated in defined drainage basins.
response to ice shelf collapse (9); the Ferrigno and Land Our map reveals to its full extent the tributaries of
glaciers in the West; and the Ninnis, Frost, Totten, Denman Recovery, Slessor and Bailey ice streams, which are
and Shirase glaciers in the East. grounded below sea level and are likely underlaid by thick
There is reasonably good agreement between observed marine sediments that favor rapid basal motion (16–17). The
surface velocity and balance velocity (Fig. 2B) near ice tributaries share common sources that extend 1,000 km inland
divides, however, large differences exist within each basin of the grounding line through a meander of slow moving
and especially near the coast, demonstrating that the direct areas. Recovery Ice Stream's two main tributaries broaden
measurement of ice velocity is crucial to capture continental- inland and reach beyond the four subglacial lakes thought to
Downloaded from www.sciencemag.org on August 25, 2011
wide ice motion accurately. Figure 1 reveals a wealth of new be a possible source of fast motion (18). The presence of 2
information. For instance, the exact pathway of ice along the subglacial lakes may accelerate the flow of the tributaries
coastline is not without surprise. In Queen Maud Land, the coming from the East, but much less clearly for the tributaries
main trunk of Jutulstraumen is not to the South through Penck coming from the West. The impact of the abrupt reduction in
trough but to the east of Neumayer Cliffs (10). The Sor basal friction associated with subglacial lakes is not apparent
Rondane Mountains were known to deflect ice flow to the in the broad pattern of ice motion. Similarly, at Lake Vostok,
East and to the West through Hansenbreen and Brydbreen the largest subglacial lake in Antarctica, flow disturbances
glaciers, but the main ice sheet discharge is from two large remain at the sub-meter scale per year (19) and are not
(80-km), un-named ice streams that flow at 100-200 m/yr expressed beyond the lake.
around the Belgica Mountains for more than 500 km inland Bedrock topography has a clear impact on the flow pattern
(11). Farther east, the fast-flowing core of Shirase Glacier of ice (Fig. 2C). Restricted ice motion is observed over major
does not extend far inland, but little-studied Rayner Glacier to subglacial (Gamburtsev) and around emergent mountains
the east flows above 100 m/yr for more than 200 km inland, (Newfoundland, Sor Rondane, Victoria Land, TransAntarctic,
presumably along a deep subglacial trough (12). In the Executive Committee Range, Ellsworth, Graham Land),
Antarctic Peninsula, the tributaries of Wilkins Ice Shelf and which deflect flow around them or limit flow through narrow
of the northern sector of George VI Ice Shelf abruptly glaciers. The tributaries of Lambert Glacier extend inland
transition to zero velocity when they mix with the floating ice among slow-moving areas of higher ground, hence higher
shelves. We attribute this spectacular termination of the basal friction, with some tributaries emerging as narrow, fast
glaciers to massive rates of basal ablation of the ice shelves streams from the flanks of the Gamburtsev Mountains, which
by the underlying warm ocean (13). is surprising this far inland from the coast. The ice flowing
A most interesting aspect is the spatial pattern of tributary down Byrd Glacier, the most extensive basin drained by a
flow. Each major glacier is the merger of several tributaries single glacier, originates from 4 tributaries that spread inland
that extend hundreds of km inland. While this was observed over more than 1,000 km. The tributaries are wider and more
in the partial mapping of Siple Coast (14) and Pine Island diffuse than in the balance velocity map, which reveals a
(15), this is now observed over the entire ice sheet. The map form of ice motion that is neither ice stream flow nor ice
reveals to its full extent the dendritic nature of drainage sheet flow but an intermediate regime which we denote
systems, the anastomosing distribution of tributaries, the patterned enhanced flow.
narrowing (acceleration) and widening (deceleration) of Conversely, major flow pathways do not follow the
tributaries inland, and their extension well beyond grounding deepest subglacial basins, hence the divide between Pine
lines toward topographic divides. On Pine Island, Thwaites Island, Rutford and Evans runs across Byrd and Bentley
and Siple Coast, the tributaries extend to ice divides trenches, and the divide between Cook Ice Shelf and David
everywhere we have data. Pine Island and Rutford share a Glacier runs across the Wilkes subglacial basin. Totten
common source in the South that connects two different sides Glacier extends 1,000 km inland through two major
of West Antarctica. Furthermore, the velocity divide is offset tributaries that reach the Aurora subglacial basin, alongside
to the East of the topographic divide by 10-15 km, which Denman, another marine-based fast-flowing glacier. In
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3. Wilkes Land, Mertz Glacier splits around a high-ground This organization of ice sheet flow into a complex set of
region to reach Astrolabe trench to the West and Wilkes meandering, size-varying, speed-varying, anastomosing
subglacial basin to the East. But Ninnis Glacier extends tributaries most certainly dominated by basal-slip motion
straight, deep south into Wilkes subglacial basin. These two challenges the view of ice sheet flow constrained by internal
glaciers exhibit an acceleration in flow at a bedrock step (20). deformation, disconnected from the coastal regions, that was
A similar initiation is visible on one western tributary of adopted as the background model for continental scale ice
Recovery Ice Stream and the western tributary of Totten, but sheet modeling (6, 21). Actual observations of continental-
over the vast majority of Antarctica, we find no area where scale ice motion reveal a new flow regime that initiates near
fast flow initiates at a bedrock step; instead, we observe topographic divides and involves a significant amount of
tributary flow extending slowly, diffusively and gradually basal-slip motion. Much remains to be understood about the
inland. mechanisms of basal motion and patterned enhanced flow,
Tributary shear margins, detected as zones of effective but our observations already imply a tighter connection
strain rate orders of magnitude higher than the background between coastal sectors and interior regions than in the
(Fig. 2A), appear at velocities of about 30 m/yr, i.e., at hypothetical case of a uniform ice sheet flow because the
substantially smaller values than the 100 m/yr quoted from concentration of ice fluxes along preferred channels enhances
the partial mapping of Siple Coast (14). This extensive the diffusivity of perturbations. It is likely that this patterned
network of shear margins reaches a few hundred km inland enhanced flow is not unique to Antarctica but a common
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and expresses a strong coupling between coastal and inland feature of ice sheets. The mapping of Antarctic ice motion
flow of ice. Yet patterned enhanced flow initiates at even therefore redefines our view of ice sheet flow dynamics and
lower speed, in both west and east Antarctica. Patterned the way ice sheets have been modeled in the past, with
enhanced flow here means flow that is not uniform, implications for improving reconstructions of past and
dominated by deformational velocity, but includes a major ongoing changes, and especially for modeling the evolution
basal slip component which varies spatially. Basal slip may of ice sheet dynamics in a warming climate.
be attributed the presence of sub-glacial valleys that
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Thick black lines delineate major ice divides (2). Thin black
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5. lines outline subglacial lakes discussed in the text. Thick
black lines along the coast are interferometrically-derived ice
sheet grounding lines (23).
Fig. 2. (A) Effective strain rate, · , color coded from 3 x 10−4
yr−1 to greater than 15 x 10−3 yr−1; (B) balance velocity (3)
color coded on a logarithmic scale as in Fig. 1; (C) bed
elevation (24) with geographic names discussed in the text;
(D) surface velocity calculated from internal deformation
with a creep parameter, A = 9 x 10−25 s−1 Pa−3. Thick black
lines in (B-D) and white lines in (A) delineate major ice
divides (2) and grounding lines (23).
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