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Bruna Barbosa Silveira, Nadia Fourrié, Vincent Guidard, Philippe Chambon, Jean-François Mahfouf, Pierre Brousseau, Patrick Moll, Thomas August, and Tim Hultberg

Abstract

The main objective of the study is to evaluate the feasibility and benefits of assimilating satellite temperature and humidity soundings (aka Level 2 or L2 profiles), instead of radiances, from the EUMETSAT Advanced Retransmission Service (EARS) into the AROME-France data assimilation system. The satellite soundings are operational forecast-independent retrievals that used the infrared sounder IASI in synergy with its companion microwave instruments AMSU-A and MHS onboard the Metop platforms. In this assimilation study, L2 profiles are used as pseudo-radiosondes, discarding vertical error correlations and the instrument vertical sensitivity in the observation operator due to the the lack of available averaging kernels. Three assimilation experiments were performed, the baseline (including all satellite radiances except those from IASI, AMSU-A and MHS sounders), the control (with observations from the baseline plus IASI, AMSU-A and MHS radiances) and the L2 experiment (with observations from the baseline and L2 temperature and humidity profiles). The assimilation runs cover the periods of the winter 2017 and summer 2018. The forecast skills of the three experiments are gauged against independent analyses and observations. Despite that the vertical observation operator is not accounted for in this study, it is found that L2 profile assimilation does not have a negative impact on 1-hour temperature and humidity forecasts, especially in the mid-troposphere. Their impacts are comparable in magnitude to the radiance ones in the operational AROME framework, except in terms of temperature and wind fields during winter where the impact is more negative than positive. These findings encourage further investigations.

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Bruna Barbosa Silveira, Nadia Fourrié, Vincent Guidard, Philippe Chambon, Jean-François Mahfouf, Pierre Brousseau, Patrick Moll, Thomas August, and Tim Hultberg

Abstract

The main objective of the study is to evaluate the feasibility and benefits of assimilating satellite temperature and humidity soundings (aka Level 2 or L2 profiles), instead of radiances, from the EUMETSAT Advanced Retransmission Service (EARS) into the AROME-France data assimilation system. The satellite soundings are operational forecast-independent retrievals that used the infrared sounder IASI in synergy with its companion microwave instruments AMSU-A and MHS on board the MetOp platforms. In this assimilation study, L2 profiles are used as pseudoradiosondes, discarding vertical error correlations and the instrument vertical sensitivity in the observation operator due to the lack of available averaging kernels. Three assimilation experiments were performed, the baseline (including all satellite radiances except those from IASI, AMSU-A, and MHS sounders), the control (with observations from the baseline plus IASI, AMSU-A, and MHS radiances), and the L2 experiment (with observations from the baseline and L2 temperature and humidity profiles). The assimilation runs cover the periods of the winter 2017 and summer 2018. The forecast skills of the three experiments are gauged against independent analyses and observations. Despite that the vertical observation operator is not accounted for in this study, it is found that L2 profile assimilation does not have a negative impact on 1-h temperature and humidity forecasts, especially in the midtroposphere. Their impacts are comparable in magnitude to the radiance ones in the operational AROME framework, except in terms of temperature and wind fields during winter where the impact is more negative than positive. These findings encourage further investigations.

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K. Dieter Klaes, Jörg Ackermann, Craig Anderson, Yago Andres, Thomas August, Régis Borde, Bojan Bojkov, Leonid Butenko, Alessandra Cacciari, Dorothée Coppens, Marc Crapeau, Stephanie Guedj, Olivier Hautecoeur, Tim Hultberg, Rüdiger Lang, Stefanie Linow, Christian Marquardt, Rosemarie Munro, Carlo Pettirossi, Gabriele Poli, Francesca Ticconi, Olivier Vandermarcq, Mayte Vasquez, and Margarita Vazquez-Navarro

Abstract

After successful launch in November 2018 and successful commissioning of Metop-C, all three satellites of the EUMETSAT Polar System (EPS) are in orbit together and operational. EPS is part of the Initial Joint Polar System (IJPS) with the US (NOAA) and provides the service in the mid-morning orbit. The Metop satellites carry a mission payload of sounding and imaging instruments, which allow provision of support to operational meteorology and climate monitoring which are the main mission objectives for EPS. Applications include Numerical Weather Prediction, atmospheric composition monitoring, and marine meteorology. Climate monitoring is supported through the generation of long time series through the program duration of 20+ years. The payload was developed and contributed by partners, including NOAA, CNES, and ESA. EUMETSAT and ESA developed the space segment in cooperation. The system has proven its value since the first satellite Metop-A, with enhanced products at high reliability for atmospheric sounding, delivered a very strong positive impact on NWP and results beyond expectations for atmospheric composition and chemistry applications. Having multiple satellites in orbit - now three, has enabled enhanced and additional products with increased impact, like atmospheric motion vector products at latitudes not accessible to geostationary observations or increased probability of radio-occultations and hence atmospheric soundings with the GRAS instruments. The paper gives an overview on the system, the embarked payload and discusses the benefits of generated products for applications and services. The conclusions point to the follow-on system, currently under development and assuring continuity for another 20+ years.

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K. Dieter Klaes, Jörg Ackermann, Craig Anderson, Yago Andres, Thomas August, Régis Borde, Bojan Bojkov, Leonid Butenko, Alessandra Cacciari, Dorothée Coppens, Marc Crapeau, Stephanie Guedj, Olivier Hautecoeur, Tim Hultberg, Rüdiger Lang, Stefanie Linow, Christian Marquardt, Rosemarie Munro, Carlo Pettirossi, Gabriele Poli, Francesca Ticconi, Olivier Vandermarcq, Mayte Vasquez, and Margarita Vazquez-Navarro

Abstract

After successful launch in November 2018 and successful commissioning of Metop-C, all three satellites of the EUMETSAT Polar System (EPS) are in orbit together and operational. EPS is part of the Initial Joint Polar System (IJPS) with the United States (NOAA) and provides the service in the midmorning orbit. The Metop satellites carry a mission payload of sounding and imaging instruments, which allow provision of support to operational meteorology and climate monitoring, which are the main mission objectives for EPS. Applications include numerical weather prediction, atmospheric composition monitoring, and marine meteorology. Climate monitoring is supported through the generation of long time series through the program duration of 20+ years. The payload was developed and contributed by partners, including NOAA, CNES, and ESA. EUMETSAT and ESA developed the space segment in cooperation. The system has proven its value since the first satellite Metop-A, with enhanced products at high reliability for atmospheric sounding, delivered a very strong positive impact on NWP and results beyond expectations for atmospheric composition and chemistry applications. Having multiple satellites in orbit—now three—has enabled enhanced and additional products with increased impact, like atmospheric motion vector products at latitudes not accessible to geostationary observations or increased probability of radio occultations and hence atmospheric soundings with the Global Navigation Satellite System (GNSS) Radio-Occultation Atmospheric Sounder (GRAS) instruments. The paper gives an overview of the system and the embarked payload and discusses the benefits of generated products for applications and services. The conclusions point to the follow-on system, currently under development and assuring continuity for another 20+ years.

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Fiona Hilton, Raymond Armante, Thomas August, Chris Barnet, Aurelie Bouchard, Claude Camy-Peyret, Virginie Capelle, Lieven Clarisse, Cathy Clerbaux, Pierre-Francois Coheur, Andrew Collard, Cyril Crevoisier, Gaelle Dufour, David Edwards, Francois Faijan, Nadia Fourrié, Antonia Gambacorta, Mitchell Goldberg, Vincent Guidard, Daniel Hurtmans, Samuel Illingworth, Nicole Jacquinet-Husson, Tobias Kerzenmacher, Dieter Klaes, Lydie Lavanant, Guido Masiello, Marco Matricardi, Anthony McNally, Stuart Newman, Edward Pavelin, Sebastien Payan, Eric Péquignot, Sophie Peyridieu, Thierry Phulpin, John Remedios, Peter Schlüssel, Carmine Serio, Larrabee Strow, Claudia Stubenrauch, Jonathan Taylor, David Tobin, Walter Wolf, and Daniel Zhou

The Infrared Atmospheric Sounding Interferometer (IASI) forms the main infrared sounding component of the European Organisation for the Exploitation of Meteorological Satellites's (EUMETSAT's) Meteorological Operation (MetOp)-A satellite (Klaes et al. 2007), which was launched in October 2006. This article presents the results of the first 4 yr of the operational IASI mission. The performance of the instrument is shown to be exceptional in terms of calibration and stability. The quality of the data has allowed the rapid use of the observations in operational numerical weather prediction (NWP) and the development of new products for atmospheric chemistry and climate studies, some of which were unexpected before launch. The assimilation of IASI observations in NWP models provides a significant forecast impact; in most cases the impact has been shown to be at least as large as for any previous instrument. In atmospheric chemistry, global distributions of gases, such as ozone and carbon monoxide, can be produced in near–real time, and short-lived species, such as ammonia or methanol, can be mapped, allowing the identification of new sources. The data have also shown the ability to track the location and chemistry of gaseous plumes and particles associated with volcanic eruptions and fires, providing valuable data for air quality monitoring and aircraft safety. IASI also contributes to the establishment of robust long-term data records of several essential climate variables. The suite of products being developed from IASI continues to expand as the data are investigated, and further impacts are expected from increased use of the data in NWP and climate studies in the coming years. The instrument has set a high standard for future operational hyperspectral infrared sounders and has demonstrated that such instruments have a vital role in the global observing system.

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