13 research outputs found
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The Copernicus Marine Environment Monitoring Service Ocean State Report
The Copernicus Marine Environment Monitoring Service (CMEMS) Ocean State Report (OSR) provides an annual report of the state of the global ocean and European regional seas for policy and decision-makers with the additional aim of increasing general public awareness about the status of, and changes in, the marine environment. The CMEMS OSR draws on expert analysis and provides a 3-D view (through reanalysis systems), a view from above (through remote-sensing data) and a direct view of the interior (through in situ measurements) of the global ocean and the European regional seas. The report is based on the unique CMEMS monitoring capabilities of the blue (hydrography, currents), white (sea ice) and green (e.g. Chlorophyll) marine environment. This first issue of the CMEMS OSR provides guidance on Essential Variables, large-scale changes and specific events related to the physical ocean state over the period 1993â2015. Principal findings of this first CMEMS OSR show a significant increase in global and regional sea levels, thermosteric expansion, ocean heat content, sea surface temperature and Antarctic sea ice extent and conversely a decrease in Arctic sea ice extent during the 1993â2015 period. During the year 2015 exceptionally strong large-scale changes were monitored such as, for example, a strong El Niño Southern Oscillation, a high frequency of extreme storms and sea level events in specific regions in addition to areas of high sea level and harmful algae blooms. At the same time, some areas in the Arctic Ocean experienced exceptionally low sea ice extent and temperatures below average were observed in the North Atlantic Ocean
Assessing the impact of brightness temperature simulation adjustment conditions in correcting Metop-A SST over the Mediterranean Sea
Multispectral sea surface temperature (SST) algorithms applied to infrared (IR) radiometer data exhibit regional biases due to the intrinsic inability of the SST algorithm to cope with the vast range of atmospheric types, mainly influenced by water vapor and temperature profiles. Deriving a SST correction from simulated brightness temperatures (BTs), obtained by applying a Radiative Transfer Model (RTM) to Numerical Weather Prediction (NWP) atmospheric profiles and first guess SST, is one of the solutions to reduce regional biases. This solution is envisaged in the particular case of Metop-A Advanced Very High Resolution Radiometer (AVHRR) derived SST. Simulated BTs show errors, linked to RTM, atmospheric profiles or guess field errors. We investigated the conditions of adjusting simulated to observed BTs in the particular case of the Mediterranean Sea over almost one year. Our study led to define optimal spatio/temporal averaging parameters of the simulation observation differences, both during day and night, summer and colder season and for two simulation modes: operational (with reduced vertical resolution â 15 levels â NWP atmospheric profiles and two days old analysis used as first guess SST) and delayed (full vertical resolution â 91 levels â and concurrent analysis used as first guess SST). Each BT adjustment has been evaluated by comparing the corresponding corrected AVHRR SST to the AATSR SST that we adopted as validation reference. We obtained an optimized result across all defined conditions and modes for a spatial smoothing of 15 deg and a temporal averaging between 3 and 5 days. Specifically, analyses based on 10 day averages showed that a standard deviation based criterion favors spatial smoothing above 10 deg for all temporal averaging, while a bias based criterion favors shorter temporal averaging during daytime ( 10 deg) for nighttime. This study has shown also the impact of diurnal warming both in deriving BT adjustment and in validation results.BESST-SR/12/158 BELSPO STEREO II, OSI-SAF Visiting Scientist program - OSI_AS12_0
Response of the sea surface temperature to heatwaves during the France 2022 meteorological summer
International audienceThe summer of 2022 was memorable and record-breaking, ranking as the second hottest summer in France since 1900, with a seasonal surface air temperature average of 22.7ââC. In particular, France experienced multiple record-breaking heatwaves during the meteorological summer. As the main heat reservoir of the Earth system, the oceans are at the forefront of events of this magnitude which enhance oceanic disturbances such as marine heatwaves (MHWs). In this study, we investigate the sea surface temperature (SST) of French maritime basins using remotely sensed measurements to track the response of surface waters to the atmospheric heatwaves and determine the intensity of such feedback. Beyond the direct relationship between SSTs and surface air temperatures, we explore the leading atmospheric parameters affecting the upper-layer ocean heat budget. Despite some gaps in data availability, the SSTs measured during the meteorological summer of 2022 were record-breaking, the mean SST was between 1.3 and 2.6ââC above the long-term average (1982â2011), and the studied areas experienced between 4 and 22âd where the basin-averaged SSTs exceeded the maximum recorded basin-averaged SSTs from 1982 to 2011. We found a significant SST response during heatwave periods with maximum temperatures measured locally at 30.8ââC in the north-western Mediterranean Sea. Our results show that in August 2022 (31Â July to 13Â August), France experienced above-average surface solar radiation correlated with below-average total cloud cover and negative wind speed anomalies. Our attribution analysis based on a simplified mixed-layer heat budget highlights the critical role of oceanâatmosphere fluxes in initiating abnormally warm SSTs, while ocean mixing plays a crucial role in the cessation of such periods. We find that the 2âm temperatures and specific humidity that are consistently linked to the advection of warm and moist air masses are key variables across all the studied regions. Our results reveal that the influence of wind on heatwaves is variable and of secondary importance. Moreover, we observe that the incident solar radiation has a significant effect only on the Bay of Biscay (BB) and the English Channel (EC) areas. Our study findings are consistent with previous research and demonstrate the vulnerability of the Mediterranean Sea to the increasing frequency of extreme weather events resulting from climate change. Furthermore, our investigation reveals that the recurring heatwave episodes during the summer of 2022 had an undeniable impact on all the surveyed maritime areas in France. Our study therefore provides valuable insights into the complex mechanisms underlying the oceanâatmosphere interaction and demonstrates the need for an efficient and sustainable operational system combining polar-orbiting and geostationary satellites to monitor the alterations that threaten the oceans in the context of climate change
Expected Performances of the Copernicus Imaging Microwave Radiometer (CIMR) for an All-Weather and High Spatial Resolution Estimation of Ocean and Sea Ice Parameters
Climate change resulting in ocean warming, sea level rise, and sea ice melting has consequences for the global economy, navigation, and security. The Copernicus Imaging Microwave Radiometer (CIMR) mission is a high priority candidate mission within the European Copernicus Expansion program. CIMR is designed to observe the ocean and sea ice and more particularly the Arctic environment. Sea surface temperature (SST), ocean wind speed, sea surface salinity (SSS), and sea ice concentration (SIC) are fundamental variables for understanding, monitoring, and predicting the state of the ocean and sea ice. CIMR is a conically scanning microwave radiometer imager that includes channels at 1.4, 6.9, 10.65, 18.7, and 36.5 GHz, in a Sun-synchronous polar orbit, to provide SST, ocean wind speed, SSS, and SIC with an increased accuracy and/or spatial resolution. Here we analyze the performances of the CIMR mission in terms of theoretical retrieval precision and spatial resolution on the SST, SSS, and SIC products. A careful information content analysis is conducted. The CIMR performances are compared with the Advanced Microwave Scanning Radiometer 2 and the Soil Moisture Active Passive current missions. Maps of the retrieval precision based on realistic conditions are computed. CIMR will provide SST, SSS, and SIC with a spatial resolution of 15, 55, and 5 km and a precision of 0.2 K, 0.3 psu, and 5%, respectively. The SST and SIC will be retrieved at better than 30 km from the coast. CIMR is currently in preparatory phase, and if selected, it is for a launch in the 2025+ time frame. Plain Language Summary Climate change resulting in ocean warming, sea level rise, and sea ice melting has consequences for the global economy, navigation, and security. The Copernicus Imaging Microwave Radiometer mission is a high priority candidate satellite mission within the European Copernicus Expansion program. It is designed to observe the ocean and sea ice and more particularly the Arctic environment. Sea surface temperature, ocean wind speed, sea surface salinity, and sea ice concentration are fundamental variables for understanding, monitoring, and predicting the state of the ocean and sea ice. Here we analyze the performances of this new satellite mission in terms of precision and spatial resolution on the sea surface temperature, sea surface salinity, and sea ice concentration and compare it with current missions. The Copernicus Imaging Microwave Radiometer will provide sea surface temperature, sea surface salinity, and sea ice concentration with a spatial resolution of 15, 55, and 5 km and a precision of 0.2 K, 0.3 psu, and 5%, respectively. This satellite mission is currently in preparatory phase, and if selected, it is for a launch in the 2025 time frame
A homogeneous resonance energy transfer-based assay to monitor MutS/DNA interactions.
International audienceProbing the interactions of the DNA mismatch repair protein MutS with altered and damaged DNA is of great interest both for the understanding of the mismatch repair system function and for the development of tools to detect mutations. Here we describe a homogeneous time-resolved fluorescence (HTRF) assay to study the interactions of Escherichia coli MutS protein with various DNA substrates. First, we designed an indirect HTRF assay on a microtiter plate format and demonstrated its general applicability through the analysis of the interactions between MutS and mismatched DNA or DNA containing the most common lesion of the anticancer drug cisplatin. Then we directly labeled MutS with the long-lived fluorescent donor molecule europium tris-bipyridine cryptate ([TBP(Eu(3+))]) and demonstrated by electrophoretic mobility shift assay that this chemically labeled protein retained DNA mismatch binding property. Consequently, we used [TBP(Eu(3+))]-MutS to develop a faster and simpler semidirect HTRF assay
Observations depuis l'orbite géostationnaire avec Meteosat troisiÚme génération (MTG)
Meteosat troisiÚme génération (MTG), la prochaine génération de satellites météorologiques géostationnaires européens, disposera de capacités largement accrues, comparées à celles des autres missions actuellement en orbite géostationnaire. C'est un systÚme à deux satellites, avec deux instruments différents sur chaque satellite. Le nouvel imageur, dénommé FCI (Flexible Combined Imager), possÚde 16 bandes spectrales et apporte à la fois la continuité et des améliorations aux données actuelles d'imagerie pour leurs applications en prévision immédiate (PI) et en prévision numérique du temps (PNT). Il est accompagné d'un imageur d'éclairs (LI pour Lightning Imager), qui effectue des mesures optiques à la longueur d'onde de 777,4 nm. Les satellites emportant ces deux instruments sont dénommés MTG-I (imageur). Les satellites compagnons sont dénommés MTG-S (sondeur) et emportent un sondeur infrarouge hyperspectral (IRS), qui mesurera la température, l'humidité, les gaz trace et les nuages, et fournira, grùce à sa haute répétitivité temporelle, des informations sur la circulation atmosphérique. Le second instrument de MTG-S est un sondeur à haute résolution dans l'ultraviolet, le visible et le proche infrarouge (UVN) pour mesurer la composition atmosphérique, et correspondant à la mission Sentinel-4 de Copernicus. La flotte MTG comprendra six satellites, quatre satellites MTG-I et deux satellites MTG-S pour fournir respectivement 20 et 15 ans et demi de service opérationnel. Le lancement du premier satellite MTG-I est prévu en 2021 et celui du premier satellite MTG-S en 2022.Meteosat Third Generation (MTG), the next generation of European geostationary meteorological satellites, will have greatly enhanced capabilities in comparison to other current meteorological satellite missions in geostationary orbit. It is a twinsatellite system with two different instruments on each satellite. The new imager, called the Flexible Combined Imager (FCI), has 16 spectral channels and provides continuity and improvements for established imager observations and applications in nowcasting and numerical weather prediction. The companion payload to the FCI is the Lightning Imager (LI) measuring optically at a wavelength of 777.4 nm. The satellites carrying these two instruments are referred to as the MTG-I (imager) satellites. The twin-satellites are denoted MTG-S (sounder) and carry an InfraRed hyper-spectral Sounder (IRS) that will measure temperature, humidity, trace gases and clouds and, by utilising the high temporal repeat cycle, will provide information on the atmospheric flow. The second instrument on MTG-S is a high resolution Ultraviolet Visible Nearinfrared (UVN) sounder for atmospheric composition measurements, which corresponds to Copernicus Sentinel-4 mission. The MTG fleet will comprise of six satellites, four MTG-I and two MTG-S satellites providing 20 and 15.5 years of operational service, respectively. The launch of the first MTG-I is expected in 2021 and the first MTG-S is currently planned for 2022
Data Assembly and Processing for Operational Oceanography: Ten Years of Achievements
Data assembly and processing centers are essential elements of the operational oceanography infrastructure. They provide data and products needed by modeling and data assimilation systems; they also provide products directly useable for applications. This paper discusses the role and functions of the data centers for operational oceanography. It describes some of the main data assembly centers (Argo and in situ data, altimetry, sea surface temperature) developed during the Global Ocean Data Assimilation Experiment. An overview of other data centers (wind and fluxes, ocean color, sea ice) is also given. Much progress has been achieved over the past ten years to validate, intercalibrate, and merge altimeter data from multiple satellites. Accuracy and timeliness of products have been improved, and new products have been developed. The same is true for sea surface temperature data through the Global High-Resolution Sea Surface Temperature Pilot Project. A breakthrough in processing, quality control, and assembly for in situ data has also been achieved through the development of the real-time and delayed-mode Argo data system. In situ and remote-sensing data are now systematically and jointly used to calibrate, validate, and monitor over the long term the quality and consistency of the global ocean observing system. Main results are illustrated. There is also a review of the development and use of products that merge in situ and remote-sensing data. Future issues and main prospects are discussed in the conclusion