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A new technique for estimating outgoing longwave radiation using infrared window and water vapor radiances from Kalpana very high resolution radiometer
Author(s) -
Singh Randhir,
Thapliyal P. K.,
Kishtawal C. M.,
Pal P. K.,
Joshi P. C.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl031715
Subject(s) - longwave , radiance , remote sensing , environmental science , geostationary orbit , outgoing longwave radiation , geostationary operational environmental satellite , satellite , atmospheric radiative transfer codes , modtran , radiometer , radiative transfer , mean squared error , meteorology , physics , optics , mathematics , geology , convection , statistics , astronomy
A new technique for estimating the outgoing longwave radiation (OLR) from the radiances observations in the infrared window (WIN; 10.5–12.5 μ m) and water vapor (WV; 5.7–7.1 μ m) channels onboard the geostationary operational Indian National Satellite (INSAT) Kalpana has been developed. The OLR is estimated from the WIN and WV radiances via genetic algorithm (GA). The transfer functions that relate OLR and narrowband radiances (WIN and WV) were developed using radiative transfer model. It is shown that inclusion of the WV information in the development of transfer function significantly reduces the OLR retrieval error as compared to the single WIN channel approach. The analysis shows that the model OLR may be retrieved within 2.5 Wm −2 rmse using WIN and WV channels, which is smaller than the rmse by earlier methods used for OLR estimation using two channels (WIN and WV). GA technique shows the clear advantage over multi‐channel regression in the OLR retrieval from WIN and WV radiances.