The Atmospheric Infrared Sounder (AIRS) is a facility instrument aboard the second Earth Observing System (EOS) polar-orbiting platform, EOS Aqua. In combination with the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), AIRS constitutes an innovative atmospheric sounding group of visible, infrared, and microwave sensors.  AIRS data will be generated continuously. Global coverage will be obtained twice daily (day and night) on a 1:30pm sun synchronous orbit from a 705-km altitude.
                  
                  The HSB level 1B data set contains HSB calibrated and geolocated brightness temperatures in degrees Kelvin. This data set is generated from HSB Level 1A digital numbers (DN), including 4 microwave channels in the 150 - 190 GHz region of the spectrum. A day's worth of data is divided into 240 scenes each of 6 minute duration. For the HSB measurements, an individual scene consists of 135 scanlines containing 90
                  cross-track footprints; thus there is a total of 135 x 90 = 12,150 footprints per HSB scene, which coincide very closely with the AIRS infrared footprints.
                  
                  HSB is primarily a humidity sounder that provides information on snow/ice cover and precipitation using the 150 GHz window channel, and the coarse distribution of moisture in the troposphere using the 183 GHz channels. Combined with simultaneous measurements from the AIRS and AMSU-A instruments, the calibrated HSB brightness temperatures will be used to initialize the atmospheric moisture profile required for the retrieval of the final AIRS geophysical products. An HSB level 1B daily summary browse product is also available to provide users with a global quick look capability when searching for data of interest.  Summary Browse Products are high-level pictorial representations of AIRS Instrument (AIRS Infrared, AMSU-A and HSB) data designed as an aid to ordering data from the GSFC DISC or EDG.
                  
                  (The Shortname for this product is AIRHBRAD)
                  Coverage: Global, Twice Daily (Daytime and Nighttime)
                  Resolution: 13.5 km IFOV at nadir
                  Spectral Range: 4 channels
                  Channel 2 150.0 GHz
                  Channel 3 183.31 \x{00B1} 1.0 GHz
                  Channel 4 183.31 \x{00B1} 3.0 GHz
                  Channel 5 183.31 \x{00B1} 7.0 GHz
                  Note: Channel 1 (89 GHz) has been deleted from HSB.