1) Stratospheric balloons equipped with GPS radio occultation systems and dropsonde payloads were used to profile the Antarctic atmosphere as part of the Concordiasi campaign. Over 700 occultation profiles and 647 dropsonde profiles were collected.
2) Comparisons were made between refractivity profiles derived from GPS occultation data near the Antarctic Peninsula, dropsonde measurements, and the ARPEGE model. Generally good agreement within 2% was found between the occultation and model data, and within 1% between occultation and dropsonde data.
3) This demonstration of high quality occultation data from balloons indicates potential for assimilating such data into models to improve analyses of the Antarctic
Dr. Kent Miller presents an overview of his program, Space Science, at the AFOSR 2013 Spring Review. At this review, Program Officers from AFOSR Technical Divisions will present briefings that highlight basic research programs beneficial to the Air Force.
First results from_the_hubble_opal_program_jupiter_in_2015Sérgio Sacani
Os cientistas usando o Telescópio Espacial Hubble da NASA/ESA produziram novos mapas de Júpiter, que mostram as contínuas mudanças que ocorrem com a famosa Grande Mancha Vermelha. As imagens também revelam uma rara estrutura em forma de onda na atmosfera do planeta que não tinha sido vista por décadas. A nova imagem é a primeira de uma série de retratos anuais dos planetas externos do Sistema Solar, que nos darão um novo olhar desses mundos remotos, e ajudarão os cientistas a estudarem como eles mudam com o passar do tempo.
Nessa nova imagem de Júpiter, uma grande quantidade de feições foi capturada incluindo ventos, nuvens e tempestades. Os cientistas por trás dessas novas imagens, as obtiveram usando a Wide Field Camera 3 do Hubble, num período de observação de mais de 10 horas e produziram assim dois mapas completos do planeta, a partir das suas observações. Esses mapas fizeram com que fosse possível determinar a velocidade dos ventos em Júpiter, com a finalidade de identificar diferentes fenômenos na sua atmosfera além de traquear as suas feições mais famosas.
As novas imagens confirmam que a grande tempestade que tem existido na superfície de nuvens de Júpiter por no mínimo 300 anos, continua a encolher, mas mesmo que desapareça, ela irá morrer lutando. A tempestade, conhecida como Grande Mancha Vermelha, é vista aqui fazendo seus movimentos em espiral no centro da imagem do planeta. Ela tem diminuído de tamanho de maneira muito rápida de ano em ano. Mas agora, a taxa de encolhimento parece ter reduzido novamente, mesmo apesar da mancha ser cerca de 240 quilômetros menor do que era em 2014.
Dr. Kent Miller presents an overview of his program, Space Science, at the AFOSR 2013 Spring Review. At this review, Program Officers from AFOSR Technical Divisions will present briefings that highlight basic research programs beneficial to the Air Force.
First results from_the_hubble_opal_program_jupiter_in_2015Sérgio Sacani
Os cientistas usando o Telescópio Espacial Hubble da NASA/ESA produziram novos mapas de Júpiter, que mostram as contínuas mudanças que ocorrem com a famosa Grande Mancha Vermelha. As imagens também revelam uma rara estrutura em forma de onda na atmosfera do planeta que não tinha sido vista por décadas. A nova imagem é a primeira de uma série de retratos anuais dos planetas externos do Sistema Solar, que nos darão um novo olhar desses mundos remotos, e ajudarão os cientistas a estudarem como eles mudam com o passar do tempo.
Nessa nova imagem de Júpiter, uma grande quantidade de feições foi capturada incluindo ventos, nuvens e tempestades. Os cientistas por trás dessas novas imagens, as obtiveram usando a Wide Field Camera 3 do Hubble, num período de observação de mais de 10 horas e produziram assim dois mapas completos do planeta, a partir das suas observações. Esses mapas fizeram com que fosse possível determinar a velocidade dos ventos em Júpiter, com a finalidade de identificar diferentes fenômenos na sua atmosfera além de traquear as suas feições mais famosas.
As novas imagens confirmam que a grande tempestade que tem existido na superfície de nuvens de Júpiter por no mínimo 300 anos, continua a encolher, mas mesmo que desapareça, ela irá morrer lutando. A tempestade, conhecida como Grande Mancha Vermelha, é vista aqui fazendo seus movimentos em espiral no centro da imagem do planeta. Ela tem diminuído de tamanho de maneira muito rápida de ano em ano. Mas agora, a taxa de encolhimento parece ter reduzido novamente, mesmo apesar da mancha ser cerca de 240 quilômetros menor do que era em 2014.
Titan’s Topography and Shape at the Endof the Cassini MissionSérgio Sacani
With the conclusion of the Cassini mission, we present an updated topographic map of Titan,including all the available altimetry, SARtopo, and stereophotogrammetry topographic data sets availablefrom the mission. We use radial basis func tions to interpolate the sparse data set, which covers only ∼9%of Titan’s global area. The most notable updates to the topography include higher coverage of the polesof Titan, improved fits to the global shape, and a finer resolution of the global interpolation. We alsopresent a statistical analysis of the error in the derived products and perform a global minimization on aprofile-by-profile basis to account for observed biases in the input data set. We find a greater flattening ofTitan than measured, additional topographic rises in Titan’s southern hemisphere and better constrain thepossible locations of past and present liquids on Titan’s surface.
hyperspectral remote sensing and its geological applicationsabhijeet_banerjee
this is an introductory presentation on hyperspectral remote sensing, which essential deals with the distinguishing features, imaging spectrometers and its types, and some of the geological applications of hyperspectral remote sensing.
This presentation cover description of microwave remote sensing, Active and Passive Microwave remote sensing, RADAR, Slant range distortion like Foreshortening and Layover, Sar image and some Recent works in where microwave remote sensing has used to detect natural calamities
Master Thesis Final Presentation: Ionosphere monitoring in GBAS using Dual Fr...Joan Erencia
The motivation: Detection of different Ionosphere gradients, which cause different ionospheric delays in aviation applications (GBAS)
The objectives: First, estimate the airborne and ground ionospheric delays and second, monitor the ionospheric. Bias between both estimates and compare it to a threshold
The contribution: Present a GBAS Ionospheric monitor monitor that allows to estimate the ionospheric differential delay without moving to a whole Dual-Frequency GBAS concept.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
CSP Training series : solar resource assessment 2/2Leonardo ENERGY
Fifth session of the 2nd Concentrated Solar Power Training dedicated to solar resource assessment.
* DNI Variability, Frequency Distributions
* Typical Meteorological Years
* DNI measurements: broadband vs. spectral, and their limitations
* What is circumsolar radiation and why should we care in CSP/CPV?
* How much diffuse irradiance can be used in concentrators?
* How to measure and model the circumsolar irradiance?
* Spectral irradiance standards and their use for PV/CPV rating
* The AM1.5 direct standard spectrum: Why did it change? Why AM1.5?
* Use of the SMARTS radiative code to evaluate clear-sky spectral irradiances
* Sources of measured spectral irradiance data
* Spectral effects on silicon and multijunction cells and their dependence on climate
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Titan’s Topography and Shape at the Endof the Cassini MissionSérgio Sacani
With the conclusion of the Cassini mission, we present an updated topographic map of Titan,including all the available altimetry, SARtopo, and stereophotogrammetry topographic data sets availablefrom the mission. We use radial basis func tions to interpolate the sparse data set, which covers only ∼9%of Titan’s global area. The most notable updates to the topography include higher coverage of the polesof Titan, improved fits to the global shape, and a finer resolution of the global interpolation. We alsopresent a statistical analysis of the error in the derived products and perform a global minimization on aprofile-by-profile basis to account for observed biases in the input data set. We find a greater flattening ofTitan than measured, additional topographic rises in Titan’s southern hemisphere and better constrain thepossible locations of past and present liquids on Titan’s surface.
hyperspectral remote sensing and its geological applicationsabhijeet_banerjee
this is an introductory presentation on hyperspectral remote sensing, which essential deals with the distinguishing features, imaging spectrometers and its types, and some of the geological applications of hyperspectral remote sensing.
This presentation cover description of microwave remote sensing, Active and Passive Microwave remote sensing, RADAR, Slant range distortion like Foreshortening and Layover, Sar image and some Recent works in where microwave remote sensing has used to detect natural calamities
Master Thesis Final Presentation: Ionosphere monitoring in GBAS using Dual Fr...Joan Erencia
The motivation: Detection of different Ionosphere gradients, which cause different ionospheric delays in aviation applications (GBAS)
The objectives: First, estimate the airborne and ground ionospheric delays and second, monitor the ionospheric. Bias between both estimates and compare it to a threshold
The contribution: Present a GBAS Ionospheric monitor monitor that allows to estimate the ionospheric differential delay without moving to a whole Dual-Frequency GBAS concept.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
CSP Training series : solar resource assessment 2/2Leonardo ENERGY
Fifth session of the 2nd Concentrated Solar Power Training dedicated to solar resource assessment.
* DNI Variability, Frequency Distributions
* Typical Meteorological Years
* DNI measurements: broadband vs. spectral, and their limitations
* What is circumsolar radiation and why should we care in CSP/CPV?
* How much diffuse irradiance can be used in concentrators?
* How to measure and model the circumsolar irradiance?
* Spectral irradiance standards and their use for PV/CPV rating
* The AM1.5 direct standard spectrum: Why did it change? Why AM1.5?
* Use of the SMARTS radiative code to evaluate clear-sky spectral irradiances
* Sources of measured spectral irradiance data
* Spectral effects on silicon and multijunction cells and their dependence on climate
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Nationnel Matchning - ottobre 2013 - stoccolmaPaolo Beretta
Su invito dell'agenzia del Governo Svedese Arbetsförmedlingen (agenzia per il lavoro e la formazione) ho fornito consulenza e know how, nell'organizzazione di un progetto di inclusione lavorativa di persone di origine straniere.
Tra ottobre 2012 e giugno 2013, 2 delegazioni di Arbetsförmedlingen sono venute in Italia per studiare il modus operandi che ho applicato sul progetto di inclusione lavorativa Diversitalavoro, che ho ideato nel 2007, dedicato appunto a persone di origine straniera, persone con disabilità e a persone transgender. In assessment con la delegazione svedese ho fornito tutte le informazioni sulle strategie di comunicazione e di caring verso gli utenti che negli hanni ho applicato nei progetti si social entrepreneurship che ho condotto.
Ad ottobre 2013, sono stato invitato dal governo svedese ad una visita a Stoccolma finalizzata ad uno scambio formativo sulle buone pratiche di inclusione lavorativo e per l'apertura ufficiale nell'esordio di Nationell Matchning, il progetto nato da questa collaborazione Italia-Svezia.
Il 9 ottobre ho partecipato come speaker al convegno di apertura che ha visto la presenza di:
Camilla Elinder - di Arbetsförmedlingen Coordinatrice del progetto Nationell Matchning
Soledad Grafeuille - di Arbetsförmedlingen
Elisabeth Svantesson - Ministro del lavoro del Governo di Svezia
Liselotte Andersson - E.ON Diversity Manager
Ibrar Changezi - Volvo Quality Assurance Manager
Marco Buemi - Esperto UNAR - Dipartimento Pari Opportunità della Presidenza del Consiglio dei Ministri italiano
Publico aquí mis artículos sobre uso de pizarras digitales interactivas del suplemento Escolar del Heraldo de Aragón (y Heraldo de Soria). Son artículos cortos y prácticos sobre uso de las PDI en las aulas: trucos, ideas de uso, novedades, consejos.
Para más información, contactar con Paul Boutroux:
info@pbxtecnologias.es
Telf.: 976 900 392
http://www.pbxtecnologias.es
Ionospheric Behaviour Analysis over Thailand Using Radio Occultation TechniqueIJERA Editor
With the advent in the development of science and technology in the field of space and atmospheric science in
order to obtain accurate result, hence the use of radio occultation technique in the investigation of the amount of
electron density and Total Electron Content presence in equatorial region particularly over Thailand. In this
research, radio occultation data obtained from UCAR/CDAAC was used to observe daily, monthly, seasonal and
the entire year 2013 Ionospheric TEC and electron density variation due to changes and instability of solar
activities from time to time. It was observed that TEC was high (ionosphere was more disturbed or violent) in
May and spread over a wide range of altitude and summer season has the highest TEC value for the year 2013
which means at this period GNSS measurements was more prone to error. It was noted that ionospheric
variations or fluctuations was maximum between 200km and 450km altitude. The results of the study show that
ionospheric perturbation effects or irregularities depend on season and solar activity.
First light of VLT/HiRISE: High-resolution spectroscopy of young giant exopla...Sérgio Sacani
A major endeavor of this decade is the direct characterization of young giant exoplanets at high spectral resolution to determine the composition of
their atmosphere and infer their formation processes and evolution. Such a goal represents a major challenge owing to their small angular separation
and luminosity contrast with respect to their parent stars. Instead of designing and implementing completely new facilities, it has been proposed
to leverage the capabilities of existing instruments that offer either high contrast imaging or high dispersion spectroscopy, by coupling them using
optical fibers. In this work we present the implementation and first on-sky results of the HiRISE instrument at the very large telescope (VLT),
which combines the exoplanet imager SPHERE with the recently upgraded high resolution spectrograph CRIRES using single-mode fibers. The
goal of HiRISE is to enable the characterization of known companions in the H band, at a spectral resolution of the order of R = λ/∆λ = 100 000,
in a few hours of observing time. We present the main design choices and the technical implementation of the system, which is constituted of three
major parts: the fiber injection module inside of SPHERE, the fiber bundle around the telescope, and the fiber extraction module at the entrance
of CRIRES. We also detail the specific calibrations required for HiRISE and the operations of the instrument for science observations. Finally, we
detail the performance of the system in terms of astrometry, temporal stability, optical aberrations, and transmission, for which we report a peak
value of ∼3.9% based on sky measurements in median observing conditions. Finally, we report on the first astrophysical detection of HiRISE to
illustrate its potential.
Detection of an atmosphere around the super earth 55 cancri eSérgio Sacani
We report the analysis of two new spectroscopic observations of the super-Earth 55 Cancri e, in the near
infrared, obtained with the WFC3 camera onboard the HST. 55 Cancri e orbits so close to its parent
star, that temperatures much higher than 2000 K are expected on its surface. Given the brightness
of 55 Cancri, the observations were obtained in scanning mode, adopting a very long scanning length
and a very high scanning speed. We use our specialized pipeline to take into account systematics
introduced by these observational parameters when coupled with the geometrical distortions of the
instrument. We measure the transit depth per wavelength channel with an average relative uncertainty
of 22 ppm per visit and nd modulations that depart from a straight line model with a 6 condence
level. These results suggest that 55 Cancri e is surrounded by an atmosphere, which is probably
hydrogen-rich. Our fully Bayesian spectral retrieval code, T -REx, has identied HCN to be the
most likely molecular candidate able to explain the features at 1.42 and 1.54 m. While additional
spectroscopic observations in a broader wavelength range in the infrared will be needed to conrm
the HCN detection, we discuss here the implications of such result. Our chemical model, developed
with combustion specialists, indicates that relatively high mixing ratios of HCN may be caused by a
high C/O ratio. This result suggests this super-Earth is a carbon-rich environment even more exotic
than previously thought.
Historical and Contemporary Trends in the Size, Drift, and Color of Jupiterʼs...Sérgio Sacani
Observations of Jupiter’s Great Red Spot (GRS) span more than 150 years. This allows for careful measurements
of its size and drift rate. High spatial resolution spacecraft data also allow tracking of its spectral characteristics and
internal dynamics and structure. The GRS continues to shrink in longitudinal length at an approximately linear rate
of 0°.194 yr−1 and in latitudinal width at 0°.048 yr−1. Its westward drift rate (relative to System III W. longitude)
has increased from ∼0°.26/day in the 1980s to ∼0°.36/day currently. Since 2014, the GRS’s short wavelength
(<650 nm) reflectance has continued to decrease, while it has become brighter at 890 nm, indicating a change in
clouds/haze at high altitudes. In addition, its north–south color asymmetry has decreased, and the dark core has
become smaller. Internal velocities have increased on its east and west edges, and decreased on the north and south,
resulting in decreased relative vorticity and circulation. The GRS’s color changes from 2014 to 2017 may be
explained by changes in stretching vorticity or divergence acting to balance the decrease in relative vorticity.
The 2013 NRC Decadal Survey in Solar and Space Physics (Heliophysics)Art Charo
From the interior of the Sun, to the upper atmosphere and near-space environment of Earth, and outward to a region far beyond Pluto where the Sun's influence wanes, advances during the past decade in space physics and solar physics--the disciplines NASA refers to as heliophysics--have yielded spectacular insights into the phenomena that affect our home in space.
Solar and Space Physics, from the National Research Council's (NRC's) Committee for a Decadal Strategy in Solar and Space Physics, is the second NRC decadal survey in heliophysics. Building on the research accomplishments realized during the past decade, the report presents a program of basic and applied research for the period 2013-2022 that will improve scientific understanding of the mechanisms that drive the Sun's activity and the fundamental physical processes underlying near-Earth plasma dynamics, determine the physical interactions of Earth's atmospheric layers in the context of the connected Sun-Earth system, and enhance greatly the capability to provide realistic and specific forecasts of Earth's space environment that will better serve the needs of society.
Although the recommended program is directed primarily at NASA and the National Science Foundation for action, the report also recommends actions by other federal agencies, especially the parts of the National Oceanic and Atmospheric Administration charged with the day-to-day (operational) forecast of space weather. In addition to the recommendations included in this summary, related recommendations are presented in this report.
Comparison and integration of spaceborne optical and radar data for mapping i...rsmahabir
The purpose of this study was to determine how different procedures and data, such as multiple wavelengths of radar imagery and radar texture measures, independently and in combination with optical imagery influence land-cover/use classification accuracies for a study site in Sudan. Radarsat-2 C-band and phased array L-band synthetic aperture radar (PALSAR) L-band quad-polarized radar were registered with ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) optical data. Spectral signatures were obtained for multiple landscape features, classified using a maximum-likelihood decision rule, and thematic accuracies were obtained using sepa- rate validation data. There were surprising differences between the thematic accuracies of the two radar data sets, with Radarsat-2 only having a 51% accuracy and PALSAR 73%. In contrast, the optical ASTER overall accuracy was 81%. Combining the original radar and a variance texture measure increased the Radarsat-2 to 78% and PALSAR to 80%, whereas the two original radar bands together had an accuracy of 87%. Sensor fusion of optical and radar obtained an accuracy of 93%. Based on these results, the use of multiwavelength quad-polarized radar imagery combined or inte- grated with optical imagery has great potential in improving the accuracy of land- cover/use classifications. In tropical and high-latitude regions of the world, where persistent cloud cover hinders the use of optical satellite systems, land management programmes may find this research promising.
Retrieval & monitoring of atmospheric green house gases (gh gs) through remot...debasishagri
Climate change is one of the most important global environmental challenges of this century. Green House Gases (GHGs) are the main culprit for this problem. Though much of research has already been done about the distribution and sources (and sinks) of GHGs , still much more uncertainties are present. Currently, there are only a few satellite instruments in orbit which are able to measure atmospheric GHGs. The High Resolution Infrared Radiation Sounder (HIRS), the Atmospheric InfraRed Sounder (AIRS), and the Infrared Atmospheric Sounding Interferometer (IASI) perform measurements in the thermal infrared (TIR) spectral region. But these are having low sensitivity to lower troposphere. In contrast to this, the sensitivity of instruments measuring reflected solar radiation in the near-infrared (NIR)/shortwave infrared (SWIR) spectral region is much more constant (with height) and shows maximum values near the surface. At present, SCIAMACHY aboard ENVISAT launched in 2002 and TANSO (Thermal And Near infrared Sensor for carbon Observation) aboard GOSAT (Greenhouse gases Observing SATellite) launched in 2009 are the only orbiting instruments measuring in NIR region. Among all the algorithms the WFM-DOAS algorithm (Weighting Function Modified Differential Optical Absorption Spectroscopy) developed at the University of Bremen for the retrieval of trace gases from SCIAMACHY (Buchwitz et al.2005) is mostly used. This is based on the principle of differential detection of radiance in gaseous absorption channels with respect to neighboring atmospheric transparent spectral channels (not influenced by gas) to detect the conc. of desired gas. But scattering at aerosol and/or cloud particles remains a major source of uncertainty for SCIAMACHY XCO2 retrievals(Houweling 2005, Schneising 2008).Of late with the use of new merged fit window approach scientists have come up with less than 0.5 ppm error in the estimation of CO2 in the presence of thin cirrus cloud(Reuter, Buchwitz et. al. 2010). Schneising et. al.,2007,retrieved d three year’s column-averaged CO2 dry air mole fraction from the SCIAMACHY instrument using the retrieval algorithm WFM-DOAS version 1.0, with precision of about 2 ppm. In India a study was undertaken to compare the atmospheric methane concentration pattern from SCIAMACHY with the vegetation dynamics from SPOT, showed fairly good correlation of methane emission with the rice cultivation(Goroshi et. al.).
Atmospheric Correction of Remote Sensing Data_RamaRao.pptxssusercd49c0
Atmospheric correction of remote sensing data. This PPT describes development of a region sensitive atmospheric correction method for hyperspectral image processing
1. Profiling the Antarctic Atmosphere Using the GPS Radio
Occultation Technique from Stratospheric Balloons
J. Maldonado Vargas1, J.S. Haase2, F. Rabier3, P. Cocquerez4, M. Minois5, V. Guidard3, P. Wyss6, A. Johnson2 and B. Murphy2
1 Department of Electrical and Computer Engineering, University of Puerto Rico, Mayaguez Campus; jayson.maldonado@upr.edu; 2 Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, IN
3 CNRM-GAME/GMAP Meteo-France and CNRS Toulouse, France; 4 Centre National d’Etudes Spatiales, Toulouse, France; 5 SOGETI High Tech, Blagnac, France; 6 Dept of Chemistry, Purdue University, West Lafayette, IN
Intercomparison of Radio Occultation, ARPEGE model and dropsondes
Figure 6. (Left) Excess Doppler (derivative of phase) for the GPSRO observations for PRN25 corrected by high elevation satellite PRN13,
and simulated excess Doppler calculated for the ARPEGE model profile and the dropsonde profile. The excess Doppler in the GPS signal
increases as the line of sight between the balloon and the occulting GPS satellite moves lower in the atmosphere. The difference between
observed and calculated Doppler is shown in the lower left panel.
(Right) Impact parameter vs retrieved bending angle obtained using the raytracing simulation (black line) for the ARPEGE model and the
retrieved bending angle from the occultation measurements with different assumptions for in-situ refractivity at the balloon height.
Refractivity retrieval
Figure 7. (left) ARPEGE, dropsonde, and retrieved refractivity. (center) Percent refractivity difference between retrieved and ARPEGE and
dropsonde profiles above 8km. (right) Difference between ARPEGE and dropsonde profiles for the full height of profiles.
Discussion and Conclusions
• The agreement between the ARPEGE model and retrieved refractivity is better than 2%.
• The agreement between dropsonde and retrieved refractivity is better than 1%.
• This indicates the potential for assmilated radio occultation data to provide further model
improvement in the Antarctic.
• With off-the shelf receiver and antenna components and limited transmission bandwidth, the system
succeeded in providing more 711 occultations, 32% of which reached within 4 km of the surface.
• Future technological developments, in particular higher gain antennas, could easily lead to even
more of this unique type of data, with deeper penetration depth.
Acknowledgements
This work was supported by NSF grants 0814290 and ANT-1043676. We thank the following people and
organizations for their support: NSF Office of Polar Programs for the instrument deployment field support; James
Zimmerman and Mike Everly at the Purdue University AMY Chemistry Facility for assistance with hardware
development; Olivier Gallien, Jean-Marc Nicot and the team at CNES for assistance with the GPS ROC integration
into the stratospheric balloons; Steve Cohn, Junho Wang, and NCAR EOL for supplying the dropsonde dataset;
University of Puerto Rico of Mayaguez for funding a summer internship for portions of this work; Paytsar Muradyan
for assistance with the data processing. Map graphics were produced using the GMT software. Concordiasi was built
by an international scientific group and is currently supported by the following agencies: Météo-France, CNES,
CNRS/INSU, NSF, NCAR, University of Wyoming, University of Colorado, the Alfred Wegener Institute, the Met Office
and ECMWF. Concordiasi also benefits from logistic or financial support of the operational polar agencies IPEV,
PNRA, USAP and BAS, and from BSRN measurements at Concordia. Concordiasi is part of the THORPEX-IPY cluster
within the International Polar Year effort.
References
[1] David W. J. Thompson and Susan Solomon (2002), Interpretation of Recent Southern Hemisphere Climate Change, Science VOL 296.
[2] Aparicio, J., G. Deblonde, L. Garand, and S. Laroche (2009), The signature of the atmospheric compressibility factor in COSMIC, CHAMP and
GRACE radio occultation data, J. Geophys. Res.
[3] Healy, S. B. (2011), Refractivity coefficients used in the assimilation of GPS radio occultation measurements, J. Geophys. Res., 116,D01106,
doi:10.1029/2010JD014013.
[4] G. A.Hajj, E. R. kursinski, L. J. Romans, W. I. Bertiger, S. S. Leroy (2002), A technical description of atmospheric sounding by GPS occultation,
Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 238-600, 4800 Oak Grove Dr., Pasadena, CA 91109, USA.
[5] Feiqin Xie, Jennifer S. Haase and Stig Syndergaard (2008), Profiling the Atmosphere Using the Airborne GPS Radio Occultation Technique: A
Sensitivity Study, IEEE Transactions on Geoscience and Remote Sensing, VOL. 46, NO. 11.
[6] S. P. E. Keeley, N. P. Gillett, D. W. J. Thompson, S. Solomon, and P. M. Forster (2007), Is Antarctic climate most sensitive to ozone
depletion in the middle or lower stratosphere?, Geophysical Research Letters, VOL. 34, L22812, doi:10.1029/2007GL031238, 2007.
Figure 3. Geometry of the airborne GPSRO technique.
In this work, we compare occultation observations and retrieved refractivity with simulated
values of phase delays, bending angle, and refractivity using a geometrical optics raytracing
method. We compare values at several steps in the processing chain shown in figure 4 below.
Figure 4. Representation of the radio occultation processing procedure.
For a consistent comparison, geometric height coordinates must be used rather than pressure
coordinates, therefore geometric height is estimated from the atmospheric variables as follows:
ARPEGE model and dropsonde profiles
The Météofrance ARPEGE model has 70 vertical levels, and uses a stretched grid centered on
Antarctica, so that spectral truncation at T798 gives a horizontal resolution of 10–15 km over
Antarctica and 60 km at the antipodes. The model profile shown below is approximately 250 km
from the dropsonde location.
Figure 5 compares the ARPEGE model and dropsonde sounding. The geometric height takes into account the difference
between the true geoid and the WGS-84 ellipsoid, and height dependence of gravity.
Figure 5 shows small refractivity differences between the ARPEGE model and the dropsonde
profile with a maximum refractivity difference of 1.8 N-units, with the ARPEGE refractivity
higher than the dropsonde refractivity. Although relative humidity differences are large,
because of the extremely low temperatures, this does not correspond to a large difference in
specific humidity, and the moisture is not likely to be resolvable with occultation data.
Abstract
The second phase of the Antarctic Concordiasi campaign was carried out in the austral spring of
2010 to study ozone and polar stratospheric clouds, gravity waves over the Antarctic peninsula,
and data assimilation in numerical weather prediction models using observations made from
stratospheric superpressure balloons. For the first time, GPS radio occultation (GPSRO)
measurements were made from these stratospheric balloons to provide atmospheric profiles of
refractivity. Dropsondes were also deployed for assessing the quality of satellite data assimilation
over the Antarctic. We compare the GPS Radio occultation measurements near the Antarctic
Peninsula with refractivity derived from nearby dropsondes and the Méteofrance ARPEGE model
to demonstrate the potential for this data also to serve for model validation. We discuss in detail
the method used to map the dropsonde measurements and model profiles of temperature and
relative humidity as a function of pressure to refractivity as a function of geometric height.
Motivation for improving Antarctic numerical model analyses
• Climate models show that a CO2 increase in the atmosphere leads to a decrease in pressure
centered over Antartica, intensification of the Antarctic polar vortex and an increase in the
strength of the circumpolar westerlies that affect sea ice distribution and surface temperature
trends.
• However, stronger westerly flow in the Antarctic polar vortex is also correlated with trends in
total column ozone.
• To improve climate model and reanalysis quality in the Antarctic and understand these factors
forcing climate change, more independent observations of the atmosphere are required.
Concordiasi Balloon Campaign
19 long duration stratospheric balloons were deployed:
4 Balloons equipped with microphysics and ozone sensors.
2 Balloons equipped with Radio Occultation (ROC) and ozone sensors.
13 Balloons equipped with driftsonde packages for the deployment of up to 6 to 20
dropsondes profiles per day
.
A B C
Figure 1. Trajectories for all (A) and GPSRO (B) stratospheric balloons during the campaign. (C) Flight trajectories for PSC18 and
PSC19, the flights carrying the ROC instrument. PSC18 is shown in blue, PSC19 is shown in black. Diamond symbols indicate the
locations of the occultation recordings. Red diamonds show the locations of the dropsondes released from the 13 MSD balloons. The
blue star indicates the location of a dropsonde close in space and time to the occultation data analyzed below.
Figure 2. Histograms of the penetration depth of the occultation measurements for flight PSC18 (left) and PSC19 (right). Top figures
show penetration depth in terms of height above the WGS84 reference ellipsoid. Lower figures show penetration in terms of height
above the land surface.
The two balloons equipped with GPS radio occultation systems flew a combined total of 107 days
within the Antarctic polar vortex, and recorded more than 700 occultations, a comparable number
of profiles to the 647 dropsondes released by the 13 balloons equipped with driftsonde systems
during the campaign.
0 5 10 15
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20
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60
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height ( km above ellipsoid )
numberofoccultations
Flight PSC18
0 5 10 15
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20
40
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height ( km above ellipsoid )
numberofoccultations
Flight PSC19
0 5 10 15
0
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height above land surface (km)
numberofoccultations
0 5 10 15
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height above land surface (km)
numberofoccultations
GPS
GPS
Balloon
Tangent Points
GPS
rE
Center of
the Earth
rt
GPS Radio oocultation (GPSRO) is a
remote sensing technique that relies on
measurements of GPS dual-frequency
phase delays collected from an airborne
or spaceborne receiver which is tracking
a GPS satellite that is setting or rising
behind the Earth’s limb.
Methodology