The atmopheric infrared sounder data products for weather prediction and climate studies

The Atmospheric Infrared Sounder (AIRS) is a space based remote sensing instrument on the Earth Observing System Aqua Spacecraft. Aqua was launched in May of 2002 in a 1:30 pm equatorial crossing daytime ascending orbit. AIRS measures 2378 channels in the infrared from 3.7 um to 15.4 um and 4 channels in the Vis/NIR. The high number of infrared channels allows measurement of a wide range of data products useful for weather forecasting and climate studies. A major objective of the AIRS Project is to provide data products useful for improving weather forecasts. Current forecast models are very accurate and to improve upon these requires accuracies in products never achieved before. AIRS product requirements for improved forecasts include temperature profiles to 1K/km, humidity accuracies to 15%, sea surface temperature to 0.5K, and land surface temperature to 1K. Weather centers have not traditionally assimilated geophysical products, so the AIRS data products include a "Cloud Cleared Radiance" (CCR) product. The CCR products need to be accurate to 1K across the spectrum. The AIRS project has achieved the majority of the above requirements. Many of these parameters used for weather are also candidates for climate studies. The most fundamental product proposed to be used for climate studies are the AIRS calibrated radiances. It is from this product that all other products can be derived. However, with 2378 channels, each AIRS granule (file) is approximately 150 Mb in size making long term and global trending using the radiance products cumbersome. Several of the level 2 products are also candidates for climate studies including temperature layers and water vapor layers . To make climate studies easier for the user, the AIRS project has developed Level 3 products which include spatially and/or temporally aggregated AIRS data Level 2 products of various types. All AIRS Products that are currently available to the public can be obtained from the GSFC DAAC at http://daac.gsfc.nasa.gov. Additional information on the AIRS instrument can be found at http://airs.jpl.nasa.gov.