AIRS/AMSU/HSB on the Aqua mission: design, science objectives, data products, and processing systems

The Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU) and the HSB (Humidity Sounder Brazil) form an integrated cross-track scanning temperature and humidity sounding system on the Aqua satellite of the Earth Observing System (EOS). AIRS is an infrared spectrometer/radiometer which covers the 3.7 15.4 μm spectral range with 2378 spectral channels. AMSU is a 15 channel microwave radiometer operating between 23 and 89 GHz, and HSB is a four-channel microwave radiometer between 150 and 190GHz. In addition to supporting NASA’s interest in process study and climate research, AIRS is the first hyperspectral infrared radiometer designed to support NOAA/NCEP’s operational requirements for medium-range weather forecasting during its nominal 7-year lifetime. AIRS, together with the AMSU and HSB microwave radiometers, will achieve global retrieval accuracy of better then 1K rms in the lower troposphere under clear and partly cloudy conditions. This paper presents an overview of the science objectives, AIRS/AMSU/HSB data products, retrieval algorithms, and the ground data processing concepts. The EOS Aqua was launched on 4 May 2002 from Vandenburg AFB, California, into a 705km high sun synchronous orbit. Based on the excellent radiometric and spectral performance demonstrated by AIRS during pre-launch testing, which has by now been verified during on-orbit testing, we expect the assimilation of AIRS data into the forecast to result in major medium-range forecast improvements.