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Assimilation for skin SST in the NASA GEOS atmospheric data assimilation system
Author(s) -
Akella Santha,
Todling Ricardo,
Suarez Max
Publication year - 2017
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.2988
Subject(s) - radiance , atmospheric infrared sounder , environmental science , sea surface temperature , data assimilation , remote sensing , advanced very high resolution radiometer , atmospheric model , depth sounding , satellite , climatology , meteorology , geology , troposphere , geography , physics , astronomy , oceanography
The present article describes the sea surface temperature (SST) developments implemented in the Goddard Earth Observing System, Version 5 (GEOS) Atmospheric Data Assimilation System (ADAS). These are enhancements that contribute to the development of an atmosphere–ocean coupled data assimilation system using GEOS. In the current quasi‐operational GEOS‐ADAS, the SST is a boundary condition prescribed based on the OSTIA product, therefore SST and skin SST ( T s ) are identical. This work modifies the GEOS‐ADAS T s by modelling and assimilating near sea surface sensitive satellite infrared (IR) observations. The atmosphere–ocean interface layer of the GEOS atmospheric general circulation model (AGCM) is updated to include near‐surface diurnal warming and cool‐skin effects. The GEOS analysis system is also updated to directly assimilate SST‐relevant Advanced Very High Resolution Radiometer (AVHRR) radiance observations. Data assimilation experiments designed to evaluate the T s modification in GEOS‐ADAS show improvements in the assimilation of radiance observations that extend beyond the thermal infrared bands of AVHRR. In particular, many channels of hyperspectral sensors, such as those of the Atmospheric Infrared Sounder (AIRS), and Infrared Atmospheric Sounding Interferometer (IASI) are also better assimilated. We also obtained improved fit to withheld insitu buoy measurement of near‐surface SST. Evaluation of forecast skill scores show neutral to marginal benefit from the modified T s .