Open AccessUpper tropospheric humidity algorithm assessment
Author(s) -
Jackson Darren L.,
Bates John J.
Publication year - 2001
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2001jd000348
Subject(s) - troposphere , humidity , radiance , brightness temperature , brightness , middle latitudes , environmental science , relative humidity , atmospheric sciences , lapse rate , meteorology , remote sensing , geology , physics , astronomy
This study assesses a common analytic expression used to compute upper tropospheric humidity (UTH) from satellite brightness temperatures at 6.7 μm. Vertical averaging methods for UTH were found to have significant impact on the algorithm. The temperature lapse parameter β had more latitudinal variance than previously found; however, large vertical gradients in midlatitude profiles degraded UTH retrievals. The scaled reference pressure parameter P 0 did sufficiently improve the radiance to humidity relationship with exception to midlatitude profiles where P 0 exceeds 1.7. A new method for computing the reference pressure parameter is presented using HIRS channel 6 observations. Error analysis of radiance to humidity relationship indicates that absolute UTH errors increase with increasing humidity with largest errors of 15% per 1 K bias between simulated and observed brightness temperatures.