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 specified size. 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 their central value. 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. It 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.
Revised: April 5, 2005 |
Published: November 6, 2003
Citation
Genkova I.S., and R. Davies. 2003.Spatial Heterogeneity of Reflected Radiance from Globally Distributed Clouds.Geophysical Research Letters 30, no. 21:2096.PNNL-SA-38971.doi:10.1029/2003GL018194