AIRS is one of a constellation of eight hyperspectral infrared sounders, as listed in Table 1. All have broadly comparable spectral resolution and coverage, and their retrieved quantities are similar. A major goal of the NASA sounder science is to provide a unified data set from these instruments. All sounders in Table 1 except TES on Aura are co-aligned with microwave instruments.

The CLIMCAPS algorithm and the IR sounders

The CLIMCAPS Level 2 algorithm was developed to process data from hyperspectral infrared instruments (and associated microwave instruments) on multiple satellites to ensure that the AIRS record is continued into the future. CLIMCAPS currently operates on AIRS, CrIS on S-NPP, and CrIS on NOAA-20 (JPSS1) listed in Table 1. Additional details about CLIMCAPS-Aqua and the AIRS-team Level 2 data sets from Aqua are presented in the Data section of this guide. 

Summary of hyperspectral IR sounders

Table 1: Orbiting hyperspectral infrared sounders. AIRS became the first such instrument with the launch of Aqua on 4 May 2002.

*As of April 2021.