VIIRS plus CrIMSS TPW – continuing the record of high spatial resolution moisture determinations

Abstract:

Total column water vapor properties are being derived from merged VIIRS infrared measurements and CrIMSS (CrIS plus ATMS) water vapor soundings in an attempt to continue the depiction of global moisture at high spatial resolution started with MODIS. While MODIS has two channels within the 6.5-µm H₂O band and four channels within the 15-µm CO₂ band, VIIRS has no infrared (IR) absorption channels. However, the VIIRS IR windows at 8.6, 10.8 and 12 µm give some indication of low level moisture (which constitutes much of the total column amount) and CrIMSS provide complementary column moisture determinations . The VIIRS/CrIMSS algorithm follows the approach used for MODIS; a clear sky regression relationship is established between total precipitable water vapor (TPW) and VIIRS IR window brightness temperatures (BTs) and CrIMSS water vapor soundings calculated from a global training radiosonde based profile data set. A high spatial resolution surface emissivity database is used to help differentiate surface emission and atmospheric moisture absorption. CrIMSS is added in clear and partly cloudy regions to enhance the TPW depiction and to extend the coverage. This poster presents comparisons of MODIS, VIIRS-only, VIIRS-CrIMSS TPW determinations and validations against ground truth MWR and GPS.