Centered at 59 GHz is a strong atmospheric absorption region resulting from O2. The uniformly mixed nature of O2 makes this region ideally suited for atmospheric temperature sounding.
The AMSU-A uses 12 channels placed between 50 and 60 GHz for operational temperature sounding. A similar capability is provided by DMSP satellites with the SSM/T (Special Sensor Microwave Temperature Sounder), a 7-channel microwave radiometer.