Monitoring the Satellite Observations Assimilated at NCMRW

Abstract

Reception of Global Meteorological Observations at NCMRWF has increased significantly in the recent
years. Significant amount of satellite radiance observations are currently available for assimilation at
NCMRWF. NCMRWF regularly assimilates various radiance observations in its global data assimilation
systems viz. NCUM and NGFS. About 50% of total observations assimilated in these systems are satellite
radiance observations. Due to the differences in observation pre-processing, thinning, quality control and
channels selection, number of radiance observations assimilated in NCUM and NGFS are different.
The percentage of satellite radiance observations assimilated in both NCUM and NGFS are a small
fraction of the same received at NCMWF. The number of radiance observations from infrared based
satellite sensors assimilated in NCUM and NGFS are 3% and 2% respectively. The percentage of
Microwave radiance observations assimilated from instruments onboard polar satellites is slightly larger
than the same from the IR instruments, 6% and 5% respectively in NCUM and NGFS. The percentage of
geostationary radiance observations assimilated in NCUM and NGFS are approximately ~3% and 2%.