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Spatial heterogeneity of reflected radiance from globally distributed clouds
Author(s) -
Genkova Iliana,
Davies Roger
Publication year - 2003
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 - 10.1029/2003gl018194
Subject(s) - radiance , spectroradiometer , environmental science , snow , cloud cover , remote sensing , moderate resolution imaging spectroradiometer , latitude , cloud fraction , atmospheric sciences , satellite , irradiance , reflectivity , meteorology , geology , geography , optics , physics , cloud computing , geodesy , astronomy , computer science , operating system
Reflected spectral radiance measured by the Multi‐angle Imaging SpectroRadiometer (MISR) on the Terra satellite has been analyzed to determine the fraction of global cloudiness that appears to be spatially homogeneous over regions of various sizes. We exclude scenes with reflectivities less than 0.2 and high latitudes to avoid snow and ice. About 1.4 ± 0.3%, or 1 in 70, of 8.8 km cloudy regions measured at 275 m have a range of reflectivities less than ±5% of the central reflectivity value of the region. This pass rate changes slightly with viewing angle, and is sensitive to the size of the test window, rising to 11% for 1.1 km regions. The pass rate rises to a value of 2.3 ± 0.5% for 8.8 km regions if the measurement resolution is degraded to 1100 m. For the purposes of this study “global” cloudiness is limited to mid‐morning clouds.