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Evaluation of Radiative Transfer Models With Clouds
Author(s) -
Aumann Hartmut H.,
Chen Xiuhong,
Fishbein Evan,
Geer Alan,
Havemann Stephan,
Huang Xianglei,
Liu Xu,
Liuzzi Giuliano,
DeSouzaMachado Sergio,
Manning Evan M.,
Masiello Guido,
Matricardi Marco,
Moradi Isaac,
Natraj Vijay,
Serio Carmine,
Strow Larrabee,
Vidot Jerome,
Chris Wilson R.,
Wu Wan,
Yang Qiguang,
Yung Yuk L.
Publication year - 2018
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2017jd028063
Subject(s) - environmental science , radiative transfer , water vapor , initialization , cloud fraction , meteorology , histogram , cloud computing , atmospheric radiative transfer codes , standard deviation , ice cloud , remote sensing , atmospheric sciences , cloud cover , physics , computer science , geology , mathematics , statistics , optics , artificial intelligence , programming language , operating system , image (mathematics)
Data from hyperspectral infrared sounders are routinely ingested worldwide by the National Weather Centers. The cloud‐free fraction of this data is used for initializing forecasts which include temperature, water vapor, water cloud, and ice cloud profiles on a global grid. Although the data from these sounders are sensitive to the vertical distribution of ice and liquid water in clouds, this information is not fully utilized. In the future, this information could be used for validating clouds in National Weather Center models and for initializing forecasts. We evaluate how well the calculated radiances from hyperspectral Radiative Transfer Models (RTMs) compare to cloudy radiances observed by AIRS and to one another. Vertical profiles of the clouds, temperature, and water vapor from the European Center for Medium‐Range Weather Forecasting were used as input for the RTMs. For nonfrozen ocean day and night data, the histograms derived from the calculations by several RTMs at 900 cm −1 have a better than 0.95 correlation with the histogram derived from the AIRS observations, with a bias relative to AIRS of typically less than 2 K. Differences in the cloud physics and cloud overlap assumptions result in little bias between the RTMs, but the standard deviation of the differences ranges from 6 to 12 K. Results at 2,616 cm −1 at night are reasonably consistent with results at 900 cm −1 . Except for RTMs which use full scattering calculations, the bias and histogram correlations at 2,616 cm −1 are inferior to those at 900 cm −1 for daytime calculations.