AIRS moves climate research and weather prediction into the 21st century. AIRS is one of six instruments on board the Aqua satellite, part of the NASA Earth Observing System. AIRS along with its partner microwave instrument the Advanced Microwave Sounding Unit AMSU-A, represents the most advanced atmospheric sounding system ever deployed in space. Together these instruments observe the global water and energy cycles, climate variation and trends, and the response of the climate system to increased greenhouse gases.