Single-Footprint Retrievals from AIRS

The Atmospheric Infrared Sounder, on the EOS-Aqua platform, retrieves temperature, water vapor and ozone profiles (among other constituents) in the thermal infrared, as well as cloud and aerosol information. The production version retrieves profiles using L2 cloud-cleared radiances, which are created using spectral data from adjacent scenes and data from the co-located AMSU microwave instrument. Current AIRS L2 profiles have a horizontal footprint of ~40 km at nadir. We present a new research retrieval using cloudy radiances directly from AIRS L1b radiances under an optimal estimation framework. Using co-located MODIS cloud results as a priori, and updated emissivitivies derived from a new database derived from ASTER and MODIS, this reduces the nadir footprint to 13.5 km. We present early L2 results from this effort and describe how this effort will be used to better understand the atmospheric water cycle.