The impact of AIRS data on weather prediction

Observing system simulation experiments (OSSE) conducted prior to the launch of AIRS indicated significant potential for AIRS temperature soundings to improve numerical weather prediction (NWP), provided that cloud effects could be cleared effectively. Since the launch of AIRS aboard the AQUA satellite, a detailed geophysical validation of AIRS data has been performed. This included collocations of AIRS temperatures with in situ observations and model analyses, and observing system experiments (OSEs) to evaluate the actual impact of AIRS data on NWP. At the NASA Goddard Space Flight Center, we are evaluating AIRS data in several different forms, and are performing impact studies using multiple data assimilation systems. In general, the results of the OSE confirm the results of the earlier simulation experiments in that a meaningful positive impact of AIRS data is obtained and this impact depends strongly upon the assimilation of partially cloudy AIRS data.