Oceanic transport through Atlantic straits
Romain Bourdallé-Badie, Yann Drillet and Karine Béranger
Introduction
Straits play a special role in ocean circulation. They transform water masses, form currents and allow water to flow from one
basin to another. In the North Atlantic and Mediterranean area simulated using the PSY2V1 analysis and forecasting system,
there are numerous straits more or less determining large-scale circulation throughout the basin. This study focuses on straits in
two areas: the Caribbean Sea, where the Gulf Stream is formed, and the North-East Atlantic where the North Atlantic bottom
waters and Greenland current are formed. The present study is based on the transport of water masses computed by PSY2V1
from October 2001 to June 2003 after having divided up the areas into sections. We take a more detailed look at 2002.
In a warming climate, why do we see decreasing heat flux in the Arctic Ocean?Harsh Beria
This presentation was given at Global Institute of Water Security, University of Saskatchewan on 23rd July, 2015. It details my work on statistical analysis for heat flux trends for the Arctic rivers.
The Effect of Declination on The Tide Pattern in Hydroghraphic SurveyingNzar Braim
The Effect of Declination on The Tide Pattern in Hydroghraphic Surveying.
I was discussed about the tide and what's meaning of tide
and I explained it with simple figure
Retrospective analysis of hydrologic impacts in the Chesapeake Bay watershedHarsh Beria
This presentation gives a summary of my work on Chesapeake Bay modeling, carried out during the summers of 2014 at Virginia Tech. It was presented at American Water Resources Conference (AWRA) in November, 2014.
In a warming climate, why do we see decreasing heat flux in the Arctic Ocean?Harsh Beria
This presentation was given at Global Institute of Water Security, University of Saskatchewan on 23rd July, 2015. It details my work on statistical analysis for heat flux trends for the Arctic rivers.
The Effect of Declination on The Tide Pattern in Hydroghraphic SurveyingNzar Braim
The Effect of Declination on The Tide Pattern in Hydroghraphic Surveying.
I was discussed about the tide and what's meaning of tide
and I explained it with simple figure
Retrospective analysis of hydrologic impacts in the Chesapeake Bay watershedHarsh Beria
This presentation gives a summary of my work on Chesapeake Bay modeling, carried out during the summers of 2014 at Virginia Tech. It was presented at American Water Resources Conference (AWRA) in November, 2014.
DSD-INT 2020 Forecasting the Mississippi River During Hurricane SeasonDeltares
Presentation by David Welch, LMRFC, at the Delft-FEWS International User Days 2020, during Delft Software Days - Edition 2020. Thursday, 5 November 2020.
Recovery Period of Fluvial Sediment Transport after a Major Earthquake by Guan-Wei Lin* and Hsien-Li Kuo in Advancements in Civil Engineering & Technology
DSD-INT 2020 Forecasting the Mississippi River During Hurricane SeasonDeltares
Presentation by David Welch, LMRFC, at the Delft-FEWS International User Days 2020, during Delft Software Days - Edition 2020. Thursday, 5 November 2020.
Recovery Period of Fluvial Sediment Transport after a Major Earthquake by Guan-Wei Lin* and Hsien-Li Kuo in Advancements in Civil Engineering & Technology
Trends and developments report about Interim Management in The Netherlands. Holland has long been regarded as the “cradle of interim management”, where it emerged in the 1970s as a more flexible way of engaging management professionals
Our research aimed to answer a variety of questions about interim management:
• What is the typical profile of an interim manager in terms of gender, age, background, experience, and how they source assignments?
• What business sectors are more likely to use interim managers?
• How has the global recession affected the utilization and pay rates of interim managers?
• How does the pay scale of interim managers vary by functional area; by industry; and by geographic region?
• What qualities are most important in an interim manager, both from the perspective of interim managers themselves and also from a client perspective?
• What needs drive companies to seek interim management solutions?
• What is the role of interim management in the private equity arena?
• What trends are impacting the role of women in interim management?
Developing The active Learning Model to Improve the Effectiveness Study Group...iosrjce
The implementation of the entrepreneurship course in ISI Padang Panjang was not run optimally.
This research was aimed to improve the effectiveness of learning entrepreneurship in ISI Padang Panjang by
developing active learning model by using group learning method. This research used research and
development approach that consisted of preliminary study (needs analysis); model development; and model
testing (validation). Developing a model in this research refers to the ADDIE model (analysis, design,
development, implementation, evaluation). The findings of this research were (1) the process of learning in
entrepreneurship courses at ISI Padang Panjang was not functioned properly; (2) the implementation of the
course only relied on teachers’ learning center which was not effective; (3) developing a model of active
learning by using ADDIE model was valid, practical and effective
Exploratory study of the approach to school leadership development programmes...Alexander_zl
Summary: This paper discusses the findings of a small scale exploratory research study on school leadership development programmes in Latvia. A brief international perspective on leadership development practices is given to appreciate more clearly the issues facing the Latvian context. The evaluation of current research in this field reveals a number of key trends in school leadership training frameworks. This indicates a changing landscape where traditional models of delivery are being succeeded by more innovative approaches.
Semi-structured interviews with three Programme Leaders and the Head of the Association of Educational Leaders of Latvia were conducted to elicit key empirical data. The findings point to a variety of provision with many good elements. However, it is clear that there is an urgent need to develop a more consistent and improved system based on a coherent, strategic and effective framework that addresses trends in the global educational world and recognizes and responds to the Latvian context.
PSY2G: moving towards
global operational oceanography
By Nicolas Ferry
Introduction
In just a few years, Mercator has developed 3 ocean analysis and forecasting systems for the
North Atlantic. Today a new stage has been reached with PSY2G, Mercator’s first low resolution (2°),
global ocean analysis system.
Each week, the PSY2G system does operational analysis of the global ocean by assimilating all
available altimetry observations in an identical way to the work being done with PSY1v1 and PSY2v1.
PSY2G thus provides weekly ocean bulletins which are used, in particular, for seasonal forecasting by
Météo France. Mercator has thus shown its determination to contribute to GODAE (the Global Ocean
Data Assimilation Experiment).
In terms of objectives, PSY2G, due to its horizontal resolution, is of course not designed to
assimilate mesoscale processes like PSY1 or PSY2 but rather to assimilate global scale climate
signals. This is also a significant technical stage before the migration towards PSY3 (global to ¼°) and
the setting up of global mode multivariate assimilation (SAM1v2).
In this newsletter, we shall be describing the PSY2G prototype in detail. The system’s
performances are discussed by referring to a global ocean reanalysis for an 11 year period (1993 to
2003).
Dear Mercatorians,
The time has come to talk about the second MERCATOR
prototype.
2002 marks a significant development with the
commissioning of the PAM model for operational
service. PAM (for Prototype Atlantique Méditerrannée)
offers a description of the North Atlantic and
Mediterranean regions with very high horizontal
resolution. This issue of the newsletter describes how it
is being implemented.
In addition, since the winter is now over, we’ll be
discussing winter convection with a comparison of
winter 2000/2001 and winter 20001/2002.
Naturally we have not forgotten our quiz, which has
been slipped in between the two articles.
Now that we’ve filled you in, sit back, put your feet up
and have a good read!
This is a personal data visualization project based on the data collected during the Saildrone circumnavigation around Antarctica in 2019.
The full project, including the Jupyter Notebook is available here: https://github.com/mlnrt/saildrone-2019-antarctica-circumnavigation
Thermohaline Circulation & Climate ChangeArulalan T
Today I have presented "The Thermohaline Circulation and Climate Change" as Mini-Project for our Science of Climate Change Course ! We can expect THC shutdown around 2050s... OMG ! Yes, we can expect "The Day After Tomorrow" around 2100... All the images credited to the reference papers except one T-S-Sigmat created by me using CDAT5.2.
Greetings all,
This month’s newsletter is devoted to the Mediterranean Sea and its various faces.
As an introduction, an article by Drobinski et al. presents the HYMEX program (HYdrological cycle in Mediterranean
Experiment) which is aiming at better understanding the global water cycle in the Mediterranean region. The next article by
Langlais et al. is dealing with a high resolution coastal and shelf model in the Gulf of Lions. Then, Boy et al. are describing the
input from spatial gravimetry to better represent the ocean circulation in the Mediterranean Sea. The next article by D’Ovidio et
al. is telling us about tracer frontal structures induced by altimeter velocities with a lagrangian technique in the Eastern
Mediterranean Sea. The last article by L’Hévéder et al. is dealing with operational forecast of glider trajectories in the
Mediterranean Sea using the Mercator forecasts.
The next April 2009 newsletter will review the current work on ocean indices aiming at better understanding the state of the
ocean climate.
We wish you a pleasant reading.
Abstract
South Biscay coastally trapped disturbances known as gales (galernas, enbatak, galarrenak, bruilartak) are adverse phenomena that send along the Cantabrian and Basque Coast a narrow jet of sudden and violent gusts of wind that do not follow a hydrostatic balance parameterization, being faster, stronger and of a Western-North-Westerly component, and accelerate as they rush Eastward enduring their speed and intensity. These gales run the coast line from West to East strengthening in Eastern Cantabrian Seashore line from May to October.
Greetings all,
This month’s newsletter is devoted to ocean indices aiming at a better understanding of the state of the ocean climate. Ocean
climate indices can be linked to major patterns of climate variability and usually have a significant social impact. The estimation of
the ocean climate indices along with their uncertainty is thus crucial: It gives an indication of our ability to measure the ocean. It is
as well a useful tool for decision making. Ocean climate indices also provide an at-a-glance overview of the state of the ocean
climate, and a way to talk to a wider audience about the ocean observing system. Several groups of experts are now working on
various ocean indicators using ocean forecast models, satellite data and reanalysis models in observing system simulation
experiments, among which the OOPC, NOAA and MERSEA/Boss4Gmes communities for example:
http://ioc3.unesco.org/oopc/state_of_the_ocean/index.php
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/
http://www.aoml.noaa.gov/phod/cyclone/data/method.html
http://www.mersea.eu.org/Indicators-with-B4G.html
Scientific articles about Ocean indices in the present Newsletter are displayed as follows: The first article by Von Schuckmann et
al. is dealing with the estimation of global ocean indicators from a gridded hydrographic field. Then, Crosnier et al. are describing
the need to conduct intercomparison of model analyses and forecast in order for experts to provide a reliable scientific expertise
on ocean climate indicators. The next article by Coppini et al. is telling us about ocean indices computed from the Mediterranean
Forecasting System for the European Environment Agency and Boss4Gmes. Then Buarque et al. are revisiting the Tropical
Cyclone Heat Potential Index in order to better represent the ocean heat content that interacts with Hurricane. The last article by Greiner et al. is dealing with the assessment of robust ocean indicators and gives an example with oceanic predictors for the
Sahel precipitations.
The next July 2009 newsletter will review the current work on data assimilation and its techniques and progress for operational
oceanography.
We wish you a pleasant reading.
From the Arctic to the Tropics: The U.S. UNCLOS Bathymetric Mapping ProgramLarry Mayer
Since CHC2006, the University of New Hampshire’s Center for Coastal & Ocean Mapping/Joint Hydrographic Center has mapped with multibeam, the bathymetry of an additional ~220,000 km2 of seafloor in areas as diverse as the Arctic, the Northern Marianas of the western Pacific and the Gulf of Mexico. The mapping supports any potential U.S. submission for of extended continental shelves under Article 76 of the United Nations Convention of the Law of the Sea. Consequently, the mapping has concentrated on capturing the complete extent of the 2500-m isobath and the zone where the Article 76-defined foot of the slope exists. In practice, the complete area between ~1500 and ~4500 m water depths is mapped in each region (with the exception of the Arctic Ocean). The data have been collected in conditions that range from harsh Arctic sea ice to the calms of the Philippine Sea tropics. Although, some of the conditions have limited the quality of some of the data, the data quality is generally quite good and geological surprises have been uncovered on each of the cruises.
Artificial Reefs by Kuddle Life Foundation - May 2024punit537210
Situated in Pondicherry, India, Kuddle Life Foundation is a charitable, non-profit and non-governmental organization (NGO) dedicated to improving the living standards of coastal communities and simultaneously placing a strong emphasis on the protection of marine ecosystems.
One of the key areas we work in is Artificial Reefs. This presentation captures our journey so far and our learnings. We hope you get as excited about marine conservation and artificial reefs as we are.
Please visit our website: https://kuddlelife.org
Our Instagram channel:
@kuddlelifefoundation
Our Linkedin Page:
https://www.linkedin.com/company/kuddlelifefoundation/
and write to us if you have any questions:
info@kuddlelife.org
WRI’s brand new “Food Service Playbook for Promoting Sustainable Food Choices” gives food service operators the very latest strategies for creating dining environments that empower consumers to choose sustainable, plant-rich dishes. This research builds off our first guide for food service, now with industry experience and insights from nearly 350 academic trials.
Willie Nelson Net Worth: A Journey Through Music, Movies, and Business Venturesgreendigital
Willie Nelson is a name that resonates within the world of music and entertainment. Known for his unique voice, and masterful guitar skills. and an extraordinary career spanning several decades. Nelson has become a legend in the country music scene. But, his influence extends far beyond the realm of music. with ventures in acting, writing, activism, and business. This comprehensive article delves into Willie Nelson net worth. exploring the various facets of his career that have contributed to his large fortune.
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Introduction
Willie Nelson net worth is a testament to his enduring influence and success in many fields. Born on April 29, 1933, in Abbott, Texas. Nelson's journey from a humble beginning to becoming one of the most iconic figures in American music is nothing short of inspirational. His net worth, which estimated to be around $25 million as of 2024. reflects a career that is as diverse as it is prolific.
Early Life and Musical Beginnings
Humble Origins
Willie Hugh Nelson was born during the Great Depression. a time of significant economic hardship in the United States. Raised by his grandparents. Nelson found solace and inspiration in music from an early age. His grandmother taught him to play the guitar. setting the stage for what would become an illustrious career.
First Steps in Music
Nelson's initial foray into the music industry was fraught with challenges. He moved to Nashville, Tennessee, to pursue his dreams, but success did not come . Working as a songwriter, Nelson penned hits for other artists. which helped him gain a foothold in the competitive music scene. His songwriting skills contributed to his early earnings. laying the foundation for his net worth.
Rise to Stardom
Breakthrough Albums
The 1970s marked a turning point in Willie Nelson's career. His albums "Shotgun Willie" (1973), "Red Headed Stranger" (1975). and "Stardust" (1978) received critical acclaim and commercial success. These albums not only solidified his position in the country music genre. but also introduced his music to a broader audience. The success of these albums played a crucial role in boosting Willie Nelson net worth.
Iconic Songs
Willie Nelson net worth is also attributed to his extensive catalog of hit songs. Tracks like "Blue Eyes Crying in the Rain," "On the Road Again," and "Always on My Mind" have become timeless classics. These songs have not only earned Nelson large royalties but have also ensured his continued relevance in the music industry.
Acting and Film Career
Hollywood Ventures
In addition to his music career, Willie Nelson has also made a mark in Hollywood. His distinctive personality and on-screen presence have landed him roles in several films and television shows. Notable appearances include roles in "The Electric Horseman" (1979), "Honeysuckle Rose" (1980), and "Barbarosa" (1982). These acting gigs have added a significant amount to Willie Nelson net worth.
Television Appearances
Nelson's char
"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for...MMariSelvam4
The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.
Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.
By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.
In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.
UNDERSTANDING WHAT GREEN WASHING IS!.pdfJulietMogola
Many companies today use green washing to lure the public into thinking they are conserving the environment but in real sense they are doing more harm. There have been such several cases from very big companies here in Kenya and also globally. This ranges from various sectors from manufacturing and goes to consumer products. Educating people on greenwashing will enable people to make better choices based on their analysis and not on what they see on marketing sites.
Diabetes is a rapidly and serious health problem in Pakistan. This chronic condition is associated with serious long-term complications, including higher risk of heart disease and stroke. Aggressive treatment of hypertension and hyperlipideamia can result in a substantial reduction in cardiovascular events in patients with diabetes 1. Consequently pharmacist-led diabetes cardiovascular risk (DCVR) clinics have been established in both primary and secondary care sites in NHS Lothian during the past five years. An audit of the pharmaceutical care delivery at the clinics was conducted in order to evaluate practice and to standardize the pharmacists’ documentation of outcomes. Pharmaceutical care issues (PCI) and patient details were collected both prospectively and retrospectively from three DCVR clinics. The PCI`s were categorized according to a triangularised system consisting of multiple categories. These were ‘checks’, ‘changes’ (‘change in drug therapy process’ and ‘change in drug therapy’), ‘drug therapy problems’ and ‘quality assurance descriptors’ (‘timer perspective’ and ‘degree of change’). A verified medication assessment tool (MAT) for patients with chronic cardiovascular disease was applied to the patients from one of the clinics. The tool was used to quantify PCI`s and pharmacist actions that were centered on implementing or enforcing clinical guideline standards. A database was developed to be used as an assessment tool and to standardize the documentation of achievement of outcomes. Feedback on the audit of the pharmaceutical care delivery and the database was received from the DCVR clinic pharmacist at a focus group meeting.
Characterization and the Kinetics of drying at the drying oven and with micro...Open Access Research Paper
The objective of this work is to contribute to valorization de Nephelium lappaceum by the characterization of kinetics of drying of seeds of Nephelium lappaceum. The seeds were dehydrated until a constant mass respectively in a drying oven and a microwawe oven. The temperatures and the powers of drying are respectively: 50, 60 and 70°C and 140, 280 and 420 W. The results show that the curves of drying of seeds of Nephelium lappaceum do not present a phase of constant kinetics. The coefficients of diffusion vary between 2.09.10-8 to 2.98. 10-8m-2/s in the interval of 50°C at 70°C and between 4.83×10-07 at 9.04×10-07 m-8/s for the powers going of 140 W with 420 W the relation between Arrhenius and a value of energy of activation of 16.49 kJ. mol-1 expressed the effect of the temperature on effective diffusivity.
Micro RNA genes and their likely influence in rice (Oryza sativa L.) dynamic ...Open Access Research Paper
Micro RNAs (miRNAs) are small non-coding RNAs molecules having approximately 18-25 nucleotides, they are present in both plants and animals genomes. MiRNAs have diverse spatial expression patterns and regulate various developmental metabolisms, stress responses and other physiological processes. The dynamic gene expression playing major roles in phenotypic differences in organisms are believed to be controlled by miRNAs. Mutations in regions of regulatory factors, such as miRNA genes or transcription factors (TF) necessitated by dynamic environmental factors or pathogen infections, have tremendous effects on structure and expression of genes. The resultant novel gene products presents potential explanations for constant evolving desirable traits that have long been bred using conventional means, biotechnology or genetic engineering. Rice grain quality, yield, disease tolerance, climate-resilience and palatability properties are not exceptional to miRN Asmutations effects. There are new insights courtesy of high-throughput sequencing and improved proteomic techniques that organisms’ complexity and adaptations are highly contributed by miRNAs containing regulatory networks. This article aims to expound on how rice miRNAs could be driving evolution of traits and highlight the latest miRNA research progress. Moreover, the review accentuates miRNAs grey areas to be addressed and gives recommendations for further studies.
Natural farming @ Dr. Siddhartha S. Jena.pptxsidjena70
A brief about organic farming/ Natural farming/ Zero budget natural farming/ Subash Palekar Natural farming which keeps us and environment safe and healthy. Next gen Agricultural practices of chemical free farming.
1. The MERCATOR Quaterly Newsletter N°11 – October 2001 – Page 1
GIP Mercator Océan
Oceanic transport through Atlantic straits
Romain Bourdallé-Badie, Yann Drillet and Karine Béranger
Introduction
Straits play a special role in ocean circulation. They transform water masses, form currents and allow water to flow from one
basin to another. In the North Atlantic and Mediterranean area simulated using the PSY2V1 analysis and forecasting system,
there are numerous straits more or less determining large-scale circulation throughout the basin. This study focuses on straits in
two areas: the Caribbean Sea, where the Gulf Stream is formed, and the North-East Atlantic where the North Atlantic bottom
waters and Greenland current are formed. The present study is based on the transport of water masses computed by PSY2V1
from October 2001 to June 2003 after having divided up the areas into sections. We take a more detailed look at 2002.
Numerical model
PAM
The PSY2V1 analysis and forecasting system implements Mercator’s PAM ocean model (a prototype covering the North Atlantic
and Mediterranean), described in Mercator Newsletter No. 5 [Siefridt et al., 2001]. The PAM configuration was developed from
version 8.1 of the OPA ocean model [Madec et al, 1998] using the physical parameters for the Clipper project [Tréguier et al.,
2001]. The simulated area ranges from 9°N to 70°N in the Atlantic Ocean and covers all the Mediterranean Sea with a horizontal
resolution of between 5 and 7 km. This study only used the free configuration of the PAM model for comparisons with PSY2V1.
Transport through Caribbean straits
Water transport around the islands is deduced from the stream function, which indicates barotropic transport through the straits.
This study with PSY2v1 focuses on 2002, during the spin up to real time, started in October 2001. The study uses the model’s
daily output.
2. The MERCATOR Quaterly Newsletter N°11 – October 2001 – Page 2
GIP Mercator Océan
Circulation in 2002 computed during the spin up to real time
The Florida current is the main contributor to the Gulf Stream, which is why it must be represented accurately. Measurements
give widely varying transport values ranging from 23 Sv in the Yucatan Channel (KANEC campaign [Candela et al, 2003]) to over
33 Sv in the Florida current (determined from voltage measurements using cables between Florida and the Bahamas,
http://www.pmel.noaa.gov/wbcurrents/cabletransport.html).
Past studies have shown that mean transport between Florida and the Bahamas may be estimated at 31.5 ± 2 Sv [Molinari et al.,
1985; Leaman et al., 1987; Schott et al., 1988; Lee et al, 1985; Larsen and Sanford, 1985]. There may be significant daily
fluctuations of up to 10 Sv.
PSY2V1 determined the mean value for 2002 to be 29 Sv
between Florida and the Bahamas (Figure 1), which concords
with mean values found during previous studies. However,
data recorded during the KANEC campaign in the Yucatan
Channel do not fit PSY2V1 and other measurements, including
the voltage measured across the Florida Straits. This raises a
doubt over the validity of these data for it is impossible for 10
Sv to flow between the Bahamas and Cuba.
Compared with the free configuration of PAM, the mean
intensity of flow is similar in both configurations, as it is for
other Caribbean straits which globally concord with
"conventional" data. Figure 1: PSY2V1 bathymetry and mean
transport in 2002 for A1 analyses
Figure 2 represents the transport time series for 2002. The instantaneous values computed at each time step are in blue and the
values smoothed over seven days are in red. As could be expected, transport varies greatly over time, with occasional
fluctuations over ten Sverdrup.
There is no correlation between the transport computed between the Yucatan Channel ("Cuba" on the graphs) and the entrance
to the Caribbean Sea ("Porto Rico"). The correlation coefficient between these two graphs is 0.12, which is around the same
value as the forced model. This is not therefore an effect of assimilation. We may thus advance two hypotheses on the
representation of circulation in the Caribbean Sea.
Either the Caribbean Sea’s impact on the Florida current has no barotropic element, which could be explained by the size of the
Jamaica Ridge lying between Jamaica and Mexico, or the Florida current is mainly influenced by forcing, and more especially
wind forcing which limits circulation in the Caribbean sea to the East. (In 2002, PSY2V1 computed a correlation of 0.76 between
the entrance to the Caribbean Sea and the Windward Passage).
This lack of correlation can be seen in the smoothed curves of figure 2, which reveals a drop in intensity of transport (around 10
Sv) in the third month for islands in the eastern part of the Caribbean sea and the Windward Passage. The drop in intensity in the
Yucatan and Florida/Bahamas straits is only around 3 Sv.
3. The MERCATOR Quaterly Newsletter N°11 – October 2001 – Page 3
GIP Mercator Océan
Figure 2: Time series of instantaneous transport for analysis A1
(blue curve) and smoothed over 7 days (red curve).Transport is
estimated either between an island and the continent or between two
islands.
4. The MERCATOR Quaterly Newsletter N°11 – October 2001 – Page 4
GIP Mercator Océan
Variations in the Florida current do not therefore appear in the model as a direct consequence of variations in water transport
from the Caribbean Sea. The process is far more complex due to barocline or vorticity effects [Candela et al., 2003] or even the
major influence of forcing.
Conclusion
Mean transport in the Caribbean in 2003 agrees with past research. Variations also correspond. On the other hand, there is no
apparent correlation in barotropic transport between water flowing from the Caribbean Sea and the intensity of the Florida
current.
The PSY2V1 system predicts the Florida current reasonably accurately. There is quite a significant difference, however, between
the analysis and forecasts for the entrance to the Caribbean Sea. This may be due to proximity to the buffer zone and a badly
represented Brazil current.
Transport through North East Atlantic straits
Circulation through the straits of Iceland and Denmark
There are two straits in the North East Atlantic: the (Denmark
Strait, DKS) and the (Iceland-Scotland Ridge, ISR). These
form the boundary between the North Atlantic subpolar gyre
and the polar gyre of the Greenland and Norwegian Seas
(Figure 3). At the surface, Norway’s warm current—which
extends the North Atlantic drift—flows northward across the
ISR towards the Norwegian coastline. One warm branch also
flows northward through the DKS and reaches the Norwegian
Sea.
The southward circulation of cold water through these straits
causes the North Atlantic Deep Water (NADW) sub-current to
form. The NADW flows from Greenland down along the
American coastline to the South Atlantic.
In PSY2V1, the northern boundary is relatively close to these
sills. Its temperature and salinity are mainly dictated by
seasonal data (Reynaud climatology [1998]). The model’s
representation of circulation North of these sills is not therefore
very realistic. It is, however, useful to analyse the realism of
circulation downstream of these sills and in the Greenland
current that forms the northern part of the subpolar gyre.
To study this circulation in PSY2V1, we selected four sections
(Figure 4), each of which is divided up into two density classes
0<27.8 kg/m³ and 0>27.8 kg/m³ (surface and deep waters
respectively).
Figure 3: Circulation in the North Atlantic. Warm currents are
shown in yellow, orange and red and cold currents in blue,
green and black.
Figure 4: PSY2V1 bathymetry in the North East Atlantic.
Position of the four sections studied in this region: the
Denmark Strait (DKS), Iceland-Scotland Ridge (ISR), East
Greenland (EGD) and South Greenland (SGD).
5. The MERCATOR Quaterly Newsletter N°11 – October 2001 – Page 5
GIP Mercator Océan
One-year study of the PSY2V1 system (May 2002-April 2003)
Iceland-Scotland Ridge
In the Iceland-Scotland Ridge, the mean transport taken throughout the depth is a mere 2.1 Sv flowing northward. The North
Atlantic Drift (DNA), a northward flow of warmer surface waters, compensates for the southward transport of dense water from
Northern regions.
The mean annual flow of surface waters over the period in question is estimated at 7.8 Sv with a standard deviation of 4.1. This
mean transport is higher than the 4 Sv estimated by Schmitz and McCartney [1993] but similar to the 7 Sv measured during the
"Student Cruise in Faroe Waters" measurement campaign in July 2001.
PSY2V1 also computes a greater flow of bottom waters across this ridge than that actually measured. Schmitz and McCartney
and the "Student Cruise in Faroe Waters" campaign estimate a bottom water transport value of 3 Sv whereas PSY2V1 considers
there to be 5.6 Sv. The mean annual transport varies between 2.5 and 3.6 Sv, depending on the simulations carried out using the
PAM model without any assimilation.
Denmark Strait
Water masses also flow through the Denmark Strait from the North Atlantic to the Nordic Seas and vice versa. The integrated
transport of the surface layer (density below 27.8 kg/m³) is always northward. Its mean value in our study came to 6.2 Sv for a
standard deviation of 3.9. Different estimations give very different transport statistics for surface waters flowing through the
Denmark Strait. Schmitz and McCartney [1993] consider that mean transport is northward and around 2 Sv, whereas "Student
Cruise in Faroe Waters" campaign measurements indicate a southward flow of 2 Sv.
The PSY2V1 value thus appears higher than these estimations, which would mean a greater flow of warm waters north of the
Denmark Strait. In various simulations using the free PAM model, the mean transport of surface waters is also northward but with
lower values, between 3 and 4 Sv.
For bottom waters, the PSY2V1 model indicates a southward flow of 8.5 Sv for a standard deviation of 3.7 through this strait. This
value is also higher than various observations that generally agree on a mean value of around 3 Sv (Schmitz and McCartney,
1993: 3 Sv, Student Cruise in Faroe Waters, 2001: 3 Sv, Macrander et al., 2003: 3.06±0.10 Sv). This tendency to overestimate
dense water transport also occurs, to a lesser extent, in simulations carried out using PAM, a free model that generates transport
values of around 6 to 7 Sv.
ADCP measurements through this strait [Macrander et al., 2003] indicate that PSY2V1 overestimates variability. The lowest and
highest values in the simulated time series are given as 5 and 14 Sv whereas measurements taken between 1999 and 2002
indicate variations between -2 and 8 Sv.
Greenland current
South of the two straits studied above, the two branches along the Greenland coast provide information on the intensity of the
subpolar gyre. As far as surface waters are concerned, the gyre is formed when the East Greenland current meets the returning
branch of the North Atlantic Drift, but the dense waters flowing through the Denmark Strait and Iceland-Scotland Ridge also
contribute to its formation.
The mean transport in the East Greenland (EGD) current is of 33.5 Sv in all, 24.5 Sv of which is accounted for by surface waters
and 9.1 Sv by denser bottom waters. During this year of simulation, it varied between 13 and 37 Sv. These values fit well with
various estimations of EGD current intensity, such as Aagard and Cochen’s estimation [1968], which limited the EGD current to
isotherm 0°C and gave a total transport of 35 Sv. More recently, Hopkins [1991] estimated a current of between 2 Sv and 32 Sv
in the first 500 metres.
Further south, the SGD section indicates a mean transport of 35.8 Sv, 26 Sv of which is accounted for by surface waters and 9.7
Sv by bottom waters. We cannot account for all the dense waters that flowed through the ISR and DKS (14.1 Sv in all) in this
section. Some of the bottom waters do not follow the coastal current but flow further south and are not counted in the transport
through section SGD, whose boundary is 47°N.
6. The MERCATOR Quaterly Newsletter N°11 – October 2001 – Page 6
GIP Mercator Océan
Figure 5: Time series smoothed over seven days for water transport through the four sections
(May 2002 to April 2003). The mean and standard deviation in 2002 are based on the time
series without smoothing.
7. The MERCATOR Quaterly Newsletter N°11 – October 2001 – Page 7
GIP Mercator Océan
Conclusion
The PSY2V1 system greatly underestimates the intensity of currents flowing over the Iceland-Scotland Ridge and through the
Denmark Strait compared with actual measurements. This is true for both surface waters—defined herein as having a density
below 27.8 kg/m³—and bottom waters, which have a density above 27.8 kg/m³. This bias already exists in simulations without
data assimilation using PAM, but it is even stronger in analyses using PSY2V1. The PSY2V1 model also exaggerates transport
variability compared with actual measurements. The quantity of dense water coming through the two straits is 14.1 Sv (annual
mean), which indicates an intense bottom water current from the Atlantic along the American coastline. The subpolar gyre formed
by the Greenland current has intense but realistic transport values.