The Contribution of Aeolus Wind Observations to ECMWF Sea Surface Wind Forecasts

Author(s):
Zuo, H.; Stoffelen, A.; Rennie, M.; Hasager, C.B.
Publication title: Journal of Geophysical Research: Atmospheres
2024
 | Volume: 129 | Issue: 6
2024
DOI: 10.1029/2023JD039555
Abstract:
Aeolus is the first satellite mission focusing on wind profile detection from near the surface to about 30 km in height on a global scale. This study … Aeolus is the first satellite mission focusing on wind profile detection from near the surface to about 30 km in height on a global scale. This study evaluates the contribution of Aeolus winds to sea surface wind forecasts geographically by further analyzing the Observing System Experiments from the European Centre for Medium-Range Weather Forecasts (ECMWF) with scatterometer winds from the meteorological operational satellites (assimilated into the model) and the Haiyang-2B satellite (not assimilated into the model). The findings indicate that Aeolus has the ability to reduce the root-mean-square difference between scatterometer winds and background forecasts (short-range) by about 0.05%–0.16% on average for climatic regions, except for the meridional wind component in the tropics. Also, Aeolus can generally reduce zonal biases of the background forecasts, while its beneficial impact on meridional biases mainly occurs in the Northern Hemisphere extratropics and tropics. For medium-range forecast assessments, as the forecast step extends up to day 5, the positive impact of Aeolus on sea surface wind forecasts becomes more evident and is even greater than 3%, especially for extratropical ocean regions in the Southern Hemisphere. Furthermore, the impact of Aeolus shows seasonal variation, with a substantial positive impact from September 2019 to February 2020 and a negative impact mainly in March, April, and May 2020. © 2024 The Authors. more
Atmosphere OSI-SAF Ocean Validation

The CM SAF ATOVS tropospheric water vapour and temperature data record: overview of methodology and evaluation

Author(s):
Courcoux, N.; Schröder, M.
Publication title: Earth System Science Data Discussions
2015
 | Volume: 8 | Issue: 1
2015
DOI: 10.5194/essdd-8-127-2015
Abstract:
Abstract. Recently, the reprocessed Advanced Television Infrared Observation Satellite (TIROS)-N Operational Vertical Sounder (ATOVS) tropospheric wat… Abstract. Recently, the reprocessed Advanced Television Infrared Observation Satellite (TIROS)-N Operational Vertical Sounder (ATOVS) tropospheric water vapour and temperature data record has been released by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Climate Monitoring (CM SAF). ATOVS observations from the National Oceanic and Atmospheric Agency (NOAA)-15 through NOAA-19 and EUMETSAT's Meteorological operational (Metop-A) satellites have been consistently reprocessed to generate 13 years (1999–2011) of global water vapour and temperature daily and monthly means with a spatial resolution of 90 km × 90 km. After pre-processing, an optimal estimation scheme has been applied to the observations to simultaneously infer temperature and water vapour profiles. In a post-processing step an objective interpolation method (Kriging) has been applied to allow for gap filling. The product suite includes total precipitable water vapour (TPW), layer integrated water vapour (LPW) and layer mean temperature for five tropospheric layers, as well as specific humidity and temperature at six tropospheric levels and is referenced under doi:10.5676/EUM_SAF_CM/WVT_ATOVS/V001. To our knowledge this is the first time that the ATOVS record (1998–now) has been consistently reprocessed (1999–2011) to retrieve water vapour and temperature products. TPW and LPW products were compared to corresponding products from the Global Climate Observing System (GCOS) Upper-Air Network (GUAN) radiosonde observations and from the Atmospheric InfraRed Sounder (AIRS) version 5 satellite data record. The TPW shows a good agreement with the GUAN radiosonde data: average bias and root mean square error (RMSE) are −0.2 and 3.3 kg m−2, respectively. The maximum absolute (relative) bias and RMSE values decrease (increase) strongly with height. While the RMSE relative to AIRS is generally smaller, the TPW bias relative to AIRS is larger with dominant contributions from precipitating areas. The consistently reprocessed ATOVS data record exhibits an improved quality and an improved stability relative to the operational CM SAF ATOVS products when compared to the TPW from GUAN radiosonde data over the period 2004–2011. Finally, it became evident that the change in the number of satellites used for the retrieval combined with the use of the Kriging leads to breakpoints in the ATOVS data record so that a variability analysis of the data record is not recommended for the time period from January 1999 to January 2001. more
Atmosphere CM-SAF Climate Data Records Validation

The CM SAF SSM/I-based total column water vapour climate data record: methods and evaluation against re-analyses and satellite

Author(s):
Schröder, M.; Jonas, M.; Lindau, R.; Schulz, J.; Fennig, K.
Publication title: Atmospheric Measurement Techniques
2013
 | Volume: 6 | Issue: 3
2013
DOI: 10.5194/amt-6-765-2013
Abstract:
Abstract. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Climate Monitoring … Abstract. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Climate Monitoring (CM SAF) aims at the provision and sound validation of well documented Climate Data Records (CDRs) in sustained and operational environments. In this study, a total column water vapour path (WVPA) climatology from CM SAF is presented and inter-compared to water vapour data records from various data sources. Based on homogenised brightness temperatures from the Special Sensor Microwave Imager (SSM/I), a climatology of WVPA has been generated within the Hamburg Ocean–Atmosphere Fluxes and Parameters from Satellite (HOAPS) framework. Within a research and operation transition activity the HOAPS data and operation capabilities have been successfully transferred to the CM SAF where the complete HOAPS data and processing schemes are hosted in an operational environment. An objective analysis for interpolation, namely kriging, has been applied to the swath-based WVPA retrievals from the HOAPS data set. The resulting climatology consists of daily and monthly mean fields of WVPA over the global ice-free ocean. The temporal coverage ranges from July 1987 to August 2006. After a comparison to the precursor product the CM SAF SSM/I-based climatology has been comprehensively compared to different types of meteorological analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA40, ERA INTERIM and operational analyses) and from the Japan Meteorological Agency (JMA–JRA). This inter-comparison shows an overall good agreement between the climatology and the analyses, with daily absolute biases generally smaller than 2 kg m−2. The absolute value of the bias to JRA and ERA INTERIM is typically smaller than 0.5 kg m−2. For the period 1991–2006, the root mean square error (RMSE) for both reanalyses is approximately 2 kg m−2. As SSM/I WVPA and radiances are assimilated into JMA and all ECMWF analyses and to assess consistency with existing WVPA climatologies, the SSM/I-based climatology is also compared to the time series of SSM/I and TMI (Tropical Rainfall Measuring Mission Microwave Imager) WVPA from Remote Sensing Systems (RSS), leading to results consistent with the reanalyses results. This evaluation study gives confidence in consistency, accurateness and stability of the total water vapour climatology produced. more
Atmosphere CM-SAF Climate Data Records Validation

The Cold Bias in the Surface Air Temperature Simulations Over the Tibetan Plateau of RegCM4 Reduced by Adopting the 3D Sub-Grid Terrain Longwave Radiative Effect Scheme

Author(s):
Gu, C.; Huang, A.; Li, X.; Wu, Y.
Publication title: Journal of Geophysical Research: Atmospheres
2024
 | Volume: 129 | Issue: 23
2024
DOI: 10.1029/2024JD042102
Abstract:
The 3D sub-grid terrain longwave radiative effects (3DSTLRE), which significantly regulate the surface downward longwave radiation (SDLR) in the mount… The 3D sub-grid terrain longwave radiative effects (3DSTLRE), which significantly regulate the surface downward longwave radiation (SDLR) in the mountainous regions, are not described in current numerical models. We incorporated a 3DSTLRE scheme into RegCM4 to assess its influence on modeling the surface air temperature (SAT) across the Tibetan Plateau (TP). Results show that the RegCM4 adopting the parallel-plane longwave radiative scheme significantly underestimates the SAT over TP, this underestimation of SAT is clearly mitigated by considering 3DSTLRE, with the root mean square error (RMSE) decreased by 9%. The SAT simulations are improved more noticeable over western TP than entire TP and more evident at nighttime than at daytime in different seasons. Further analysis indicates that the improvement of SAT simulations over the rugged areas of TP is primarily benefited from the improved SDLR simulations. In the absence of the 3DSTLRE scheme, RegCM4 markedly underestimates SDLR by 20 W·m−2 over the entire TP, this underestimation can be greatly reduced by 15 W·m−2 through adopting the 3DSTLRE scheme, with the RMSE reduced by more than 40% over the rugged edges of TP. The increased SDLR induced by the 3DSTLRE is mainly transformed into sensible heat flux to warm the near surface air, further leading to reduced cold bias of SAT produced by the RegCM4 without 3DSTLRE. Better representing the TP thermal condition can enhance the simulation of East Asian monsoon. Therefore, incorporating the 3DSTLRE scheme in numerical models can potentially improve the ability in simulating and predicting the East Asian monsoon. © 2024. American Geophysical Union. All Rights Reserved. more
Application Atmosphere CM-SAF Climate Data Records Validation

The ERA5 global reanalysis

Author(s):
Hersbach, H.; Bell, B.; Berrisford, P.; Hirahara, S.; Horányi, A.; Muñoz-Sabater, J.; Nicolas, J.; Peubey, C.; Radu, R.; Schepers, D.; Simmons, A.; Soci, C.; Abdalla, S.; Abellan, X.; Balsamo, G.; Bechtold, P.; Biavati, G.; Bidlot, J.; Bonavita, M.; De Chiara, G.; Dahlgren, P.; Dee, D.; Diamantakis, M.; Dragani, R.; Flemming, J.; Forbes, R.; Fuentes, M.; Geer, A.; Haimberger, L.; Healy, S.; Hogan, R.J.; Hólm, E.; Janisková, M.; Keeley, S.; Laloyaux, P.; Lopez, P.; Lupu, C.; Radnoti, G.; de Rosnay, P.; Rozum, I.; Vamborg, F.; Villaume, S.; Thépaut, J.-N.
Publication title: Quarterly Journal of the Royal Meteorological Society
2020
 | Volume: 146 | Issue: 730
2020
DOI: 10.1002/qj.3803
Abstract:
Within the Copernicus Climate Change Service (C3S), ECMWF is producing the ERA5 reanalysis which, once completed, will embody a detailed record of the… Within the Copernicus Climate Change Service (C3S), ECMWF is producing the ERA5 reanalysis which, once completed, will embody a detailed record of the global atmosphere, land surface and ocean waves from 1950 onwards. This new reanalysis replaces the ERA-Interim reanalysis (spanning 1979 onwards) which was started in 2006. ERA5 is based on the Integrated Forecasting System (IFS) Cy41r2 which was operational in 2016. ERA5 thus benefits from a decade of developments in model physics, core dynamics and data assimilation. In addition to a significantly enhanced horizontal resolution of 31 km, compared to 80 km for ERA-Interim, ERA5 has hourly output throughout, and an uncertainty estimate from an ensemble (3-hourly at half the horizontal resolution). This paper describes the general set-up of ERA5, as well as a basic evaluation of characteristics and performance, with a focus on the dataset from 1979 onwards which is currently publicly available. Re-forecasts from ERA5 analyses show a gain of up to one day in skill with respect to ERA-Interim. Comparison with radiosonde and PILOT data prior to assimilation shows an improved fit for temperature, wind and humidity in the troposphere, but not the stratosphere. A comparison with independent buoy data shows a much improved fit for ocean wave height. The uncertainty estimate reflects the evolution of the observing systems used in ERA5. The enhanced temporal and spatial resolution allows for a detailed evolution of weather systems. For precipitation, global-mean correlation with monthly-mean GPCP data is increased from 67% to 77%. In general, low-frequency variability is found to be well represented and from 10 hPa downwards general patterns of anomalies in temperature match those from the ERA-Interim, MERRA-2 and JRA-55 reanalyses. © 2020 The Authors. Quarterly Journal of the Royal Meteorological Society published by John Wiley & Sons Ltd on behalf of the Royal Meteorological Society. more
Application Climate Data Records Cryosphere OSI-SAF

The EU-FP7 ERA-CLIM2 Project Contribution to Advancing Science and Production of Earth System Climate Reanalyses

Author(s):
Buizza, Roberto; Brönnimann, Stefan; Haimberger, Leopold; Laloyaux, Patrick; Martin, Matthew J.; Fuentes, Manuel; Alonso-Balmaseda, Magdalena; Becker, Andreas; Blaschek, Michael; Dahlgren, Per; de Boisseson, Eric; Dee, Dick; Doutriaux-Boucher, Marie; Feng, Xiangbo; John, Viju O.; Haines, Keith; Jourdain, Sylvie; Kosaka, Yuki; Lea, Daniel; Lemarié, Florian; Mayer, Michael; Messina, Palmira; Perruche, Coralie; Peylin, Philippe; Pullainen, Jounie; Rayner, Nick; Rustemeier, Elke; Schepers, Dinand; Saunders, Roger; Schulz, Jörg; Sterin, Alexander; Stichelberger, Sebastian; Storto, Andrea; Testut, Charles-Emmanuel; Valente, Maria-Antóonia; Vidard, Arthur; Vuichard, Nicolas; Weaver, Anthony; While, James; Ziese, Markus
Publication title: Bulletin of the American Meteorological Society
2018
 | Volume: 99 | Issue: 5
2018
DOI: 10.1175/BAMS-D-17-0199.1
Abstract:
Abstract The European Reanalysis of Global Climate Observations 2 (ERA-CLIM2) is a European Union Seventh Framework Project started in January 2014 an… Abstract The European Reanalysis of Global Climate Observations 2 (ERA-CLIM2) is a European Union Seventh Framework Project started in January 2014 and due to be completed in December 2017. It aims to produce coupled reanalyses, which are physically consistent datasets describing the evolution of the global atmosphere, ocean, land surface, cryosphere, and the carbon cycle. ERA-CLIM2 has contributed to advancing the capacity for producing state-of-the-art climate reanalyses that extend back to the early twentieth century. ERA-CLIM2 has led to the generation of the first European ensemble of coupled ocean, sea ice, land, and atmosphere reanalyses of the twentieth century. The project has funded work to rescue and prepare observations and to advance the data-assimilation systems required to generate operational reanalyses, such as the ones planned by the European Union Copernicus Climate Change Service. This paper summarizes the main goals of the project, discusses some of its main areas of activities, and presents some of its key results. more
Application EUM-Secr International cooperation

The development and persistence of soil moisture stress during drought across southwestern Germany

Author(s):
Tijdeman, E.; Menzel, L.
Publication title: Hydrology and Earth System Sciences
2021
 | Volume: 25 | Issue: 4
2021
DOI: 10.5194/hess-25-2009-2021
Abstract:
The drought of 2018 in central and northern Europe showed once more the large impact that this natural hazard can have on the environment and society.… The drought of 2018 in central and northern Europe showed once more the large impact that this natural hazard can have on the environment and society. Such droughts are often seen as slowly developing phenomena. However, root zone soil moisture deficits can rapidly develop during periods lacking precipitation and meteorological conditions that favor high evapotranspiration rates. These periods of soil moisture stress can persist for as long as the meteorological drought conditions last, thereby negatively affecting vegetation and crop health. In this study, we aim to characterize past soil moisture stress events over the croplands of southwestern Germany and, furthermore, to relate the characteristics of these past events to different soil and climate properties.We first simulated daily soil moisture over the period 1989 2018 on a 1 km resolution grid, using the physically based hydrological model TRAIN. We then derived various soil moisture stress characteristics, including probability, development time, and persistence, from the simulated time series of all agricultural grid cells (n 15000). Logistic regression and correlation were then applied to relate the derived characteristics to the plant-Available storage capacity of the root zone and to the climatological setting. Finally, sensitivity analyses were carried out to investigate how results changed when using a different parameterization of the root zone, i.e., soil based or fixed, or when assessing soil moisture drought (anomaly) instead of stress. Results reveal that the majority of agricultural grid cells across the study region reached soil moisture stress during prominent drought years. The development time of these soil moisture stress events varied substantially, from as little as 10 d to over 4 months. The persistence of soil moisture stress varied as well and was especially high for the drought of 2018. A strong control on the probability and development time of soil moisture stress was found to be the storage capacity of the root zone, whereas the persistence was not strongly linearly related to any of the considered controls. On the other hand, the sensitivity analyses revealed the increased control of climate on soil moisture stress characteristics when using a fixed instead of a soil-based root zone storage. Thus, the strength of different controls depends on the assumptions made during modeling. Nonetheless, the storage capacity of the root zone, whether it is a characteristic of the soil or a difference between a shallow or deep rooting crop, remains an important control on soil moisture stress characteristics. This is different for SM drought characteristics, which have little or contrasting relation with the storage capacity of the root zone. Overall, the results give insight to the large spatial and temporal variability in soil moisture stress characteristics and suggest the importance of considering differences in root zone soil storage for agricultural drought assessments. © 2021 Copernicus GmbH. All rights reserved. more
Application Atmosphere CM-SAF Climate Data Records

The Effect of Error Non-Orthogonality on Triple Collocation Analyses

Author(s):
Vogelzang, Jur; Stoffelen, Ad; Verhoef, Anton
Publication title: Remote Sensing
2022
 | Volume: 14 | Issue: 17
2022
DOI: 10.3390/rs14174268
Abstract:
Triple collocation analysis is an established technique for calculating the relative linear intercalibration coefficients and observation error varian… Triple collocation analysis is an established technique for calculating the relative linear intercalibration coefficients and observation error variances for physical quantities measured simultaneously in space and time by three different observation systems. A simple parameterized error model is used. It relies on a few assumptions, one of which is that the observation errors are independent of the magnitude of the observed quantities. This is referred to as error orthogonality. Using an ocean surface vector winds data set of 44,948 collocations, this study shows that the violation of error orthogonality does affect the calibration coefficients but has only a small second-order effect on the observation error variances of the calibrated data. more
Atmosphere Climate Data Records Method OSI-SAF

The EUMETSAT sea ice concentration climate data record

Author(s):
Tonboe, Rasmus T.; Eastwood, Steinar; Lavergne, Thomas; Sørensen, Atle M.; Rathmann, Nicholas; Dybkjær, Gorm; Pedersen, Leif Toudal; Høyer, Jacob L.; Kern, Stefan
Publication title: The Cryosphere
2016
 | Volume: 10 | Issue: 5
2016
DOI: 10.5194/tc-10-2275-2016
Abstract:
Abstract. An Arctic and Antarctic sea ice area and extent dataset has been generated by EUMETSAT's Ocean and Sea Ice Satellite Application Facility (O… Abstract. An Arctic and Antarctic sea ice area and extent dataset has been generated by EUMETSAT's Ocean and Sea Ice Satellite Application Facility (OSISAF) using the record of microwave radiometer data from NASA's Nimbus 7 Scanning Multichannel Microwave radiometer (SMMR) and the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave/Imager (SSM/I) and Special Sensor Microwave Imager and Sounder (SSMIS) satellite sensors. The dataset covers the period from October 1978 to April 2015 and updates and further developments are planned for the next phase of the project. The methodology for computing the sea ice concentration uses (1) numerical weather prediction (NWP) data input to a radiative transfer model for reduction of the impact of weather conditions on the measured brightness temperatures; (2) dynamical algorithm tie points to mitigate trends in residual atmospheric, sea ice, and water emission characteristics and inter-sensor differences/biases; and (3) a hybrid sea ice concentration algorithm using the Bristol algorithm over ice and the Bootstrap algorithm in frequency mode over open water. A new sea ice concentration uncertainty algorithm has been developed to estimate the spatial and temporal variability in sea ice concentration retrieval accuracy. A comparison to US National Ice Center sea ice charts from the Arctic and the Antarctic shows that ice concentrations are higher in the ice charts than estimated from the radiometer data at intermediate sea ice concentrations between open water and 100 % ice. The sea ice concentration climate data record is available for download at www.osi-saf.org, including documentation. more
Climate Data Records Cryosphere Method OSI-SAF Validation

The GOME-2 instrument on the Metop series of satellites: instrument design, calibration, and level 1 data processing – an overview

Author(s):
Munro, Rosemary; Lang, Rüdiger; Klaes, Dieter; Poli, Gabriele; Retscher, Christian; Lindstrot, Rasmus; Huckle, Roger; Lacan, Antoine; Grzegorski, Michael; Holdak, Andriy; Kokhanovsky, Alexander; Livschitz, Jakob; Eisinger, Michael
Publication title: Atmospheric Measurement Techniques
2016
 | Volume: 9 | Issue: 3
2016
DOI: 10.5194/amt-9-1279-2016
Abstract:
Abstract. The Global Ozone Monitoring Experiment-2 (GOME-2) flies on the Metop series of satellites, the space component of the EUMETSAT Polar System.… Abstract. The Global Ozone Monitoring Experiment-2 (GOME-2) flies on the Metop series of satellites, the space component of the EUMETSAT Polar System. In this paper we will provide an overview of the instrument design, the on-ground calibration and characterization activities, in-flight calibration, and level 0 to 1 data processing. The current status of the level 1 data is presented and points of specific relevance to users are highlighted. Long-term level 1 data consistency is also discussed and plans for future work are outlined. The information contained in this paper summarizes a large number of technical reports and related documents containing information that is not currently available in the published literature. These reports and documents are however made available on the EUMETSAT web pages and readers requiring more details than can be provided in this overview paper will find appropriate references at relevant points in the text. more
Climate Data Records EUM-Secr Method
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