AIRS, the first hyper-spectral infrared sounder for operational weather forecasting

AIRS, the Atmospheric Infrared Sounder on the EOS-Aqua, is an infrared radiometer that covers the 3.7-15.4 micron spectral range with spectral resolving power of 1200. AIRS is a cross-track scanner with 15 km nadir footprints, which produces global high precision spectra twice each day from 708 km orbital altitude. In addition to supporting NASA´s interest in process study and climate research, AIRS is the first hyper-spectral infrared radiometer designed to support the requirements for operational medium range weather forecasting during its nominal seven year lifetime. AIRS, together with the AMSU and HSB microwave radiometers, are designed to achieve global retrieval accuracy of better then 1K rms in the lower troposphere under clear and partly cloudy conditions. Based on the excellent radiometric and spectral performance demonstrated during the pre-launch testing, we expect the assimilation of AIRS data into the forecast model to result in major forecast improvements. We present highlights of the AIRS pre-launch characterization results and concepts for ground data processing using direct retrieval and direct assimilation. Launch of AIRS on the EOS AQUA is scheduled for July, 2001