Enhancements of Satellite Data Assimilation over Antarctica

International audience The Concordiasi field experiment, which is taking place in Antarctica, involves the launching of radiosoundings and stratospheric balloons. One of the main goals of this campaign is the validation of the Infrared Atmospheric Sounding Interferometer (IASI) radiance assimilation...

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Bibliographic Details
Published in:Monthly Weather Review
Main Authors: Bouchard, Aurélie, Rabier, Florence, Guidard, Vincent, Karbou, Fatima
Other Authors: Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Concordiasi
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2010
Subjects:
Antarctica
Satellite observations
Data assimilation
Numerical weather prediction
Radiosonde observations
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean
Atmosphere
Antarc*
Sea ice
Online Access:https://hal-meteofrance.archives-ouvertes.fr/meteo-00564271
https://hal-meteofrance.archives-ouvertes.fr/meteo-00564271/document
https://hal-meteofrance.archives-ouvertes.fr/meteo-00564271/file/%5B15200493%20-%20Monthly%20Weather%20Review%5D%20Enhancements%20of%20Satellite%20Data%20Assimilation%20over%20Antarctica.pdf
https://doi.org/10.1175/2009MWR3071.1
Description
Summary:International audience The Concordiasi field experiment, which is taking place in Antarctica, involves the launching of radiosoundings and stratospheric balloons. One of the main goals of this campaign is the validation of the Infrared Atmospheric Sounding Interferometer (IASI) radiance assimilation. Prior to the campaign, it was necessary to improve satellite data assimilation at high latitudes. Two types of sensors, microwave and infrared, have been considered to help with this issue. A major problem associated with microwave satellite data is the calculation of the surface emissivity. An innovative approach, based on satellite observations, improves the surface emissivity modeling over land and sea ice within the constraints of the four-dimensional variational data assimilation (4D-VAR) system. With this new calculation of emissivity, it has been possible to include many more microwave observations during the assimilation. In this study, this method has been applied to high latitudes, after some adjustments have been made to assimilate additional Advanced Microwave Sounding Unit-A/B (AMSU-A/B) data over sea ice and snow. The use of additional data from IASI and the Atmospheric Infrared Sounder (AIRS) sensors over land and sea ice has also been tested. The use of the microwave and infrared data over this polar area has modified the dynamical and thermodynamical model fields such as the snow precipitation quantity. Additional data have been found to have a positive impact on the skill of a model specially tuned for Antarctica.

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