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.
The ... AIRS Visible/Near Infrared (VIS/NIR) level 1B data set contains AIRS visible and near-infrared calibrated and geolocated radiances in W/m^2/micron/steradian. This data set is generated from AIRS level 1A digital numbers (DN), including 4 channels in the 0.4 to 1.0 um region of the spectrum. A day's worth of AIRS data is divided into 240 scenes each of 6 minute duration. For the AIRS visible/near IR measurements, an individual scene contains 135 scanlines with a scanline containing 720 cross-track pixels and 9 along-track pixels; there is a total of 720 x 9 x 135 = 874,800 visible/near-IR pixels per scene.
AIRS employs a 49.5 degree crosstrack scanning with a 1.1 degree instantaneous field of view (IFOV) to provide twice daily (day and night) coverage of essentially the entire globe in a 1:30 PM sun synchronous orbit from a 705 km altitude. The primary purpose of the visible/near IR channels is the detection and flagging of significant inhomogeneities in the AIRS infrared field-of-view,which may adversely impact the quality of the temperature and moisture soundings. The AIRS VIS/NIR channels will also be used for comparative studies with the higher resolution MODIS channels contained within this spectral region.
(The Shortname for this product is AIRVBRAD_NRT)
Coverage: Global, Twice Daily (Daytime and Nighttime)
Resolution: 2.3 km IFOV at nadir
Spectral Range: Four channels, from 0.4 - 1.0 um:
Wavelengths at 50% peak response:
Channel 1 0.41 um - 0.44 um
Channel 2 0.58 um - 0.68 um
Channel 3 0.71 um - 0.92 um
Channel 4 0.49 um - 0.94 um