Uses of COSMIC data to cross-calibrate AMSU-A

In May 1998, NOAA launched the first Advanced Microwave Sounding Unit A (AMSU-A) on board NOAA-15 Polar-orbiting Operational Environmental Satellite (POES) missions . This was the beginning of over a decade long mission (1998 to present) to continue the satellite-based global atmospheric temperature profile time series generated from Microwave Sounding Unit (MSU) . The same instrument was also launched on board of NOAA 16, 17, 18, and 19.

AMSU-A is a multi channel microwave radiometer, and a cross track scanning instrument. A radiometric bias of AMSU-A instrument can affect weather forecasts and climate research. This study will assess the quality of the AMSU-A brightness temperatures using the Constellation Observing System for Meteorological, Ionosphere and Climate (COSMIC) data.

COSMIC atmospheric profiles were used to calculate the brightness temperatures using the Community Radiative Transfer Model (CRTM). From June 2009 through December 2009 COSMIC profiles were spatially collocated with AMSU-A on NOAA-18 and 19. These environmental (geophysical) parameters needed to run the CRTM were obtained from COSMIC data set. The main output for the CRTM is the estimated brightness temperature at the defined operating frequency and incidence angle. COSMIC observations have been utilized in this study due to their high accuracy and global coverage. Final results of this study will be presented in the final paper.