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Relations between albedos and emissivities from MODIS and ASTER data over North African Desert
Author(s) -
Zhou L.,
Dickinson R. E.,
Ogawa K.,
Tian Y.,
Jin M.,
Schmugge T.,
Tsvetsinskaya E.
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 - 10.1029/2003gl018069
Subject(s) - emissivity , advanced spaceborne thermal emission and reflection radiometer , albedo (alchemy) , environmental science , remote sensing , atmospheric sciences , arid , climatology , geology , digital elevation model , physics , art , paleontology , performance art , optics , art history
This paper analyzes relations among MODIS surface albedos, ASTER broadband (3–14 μm) emissivities, and a soil taxonomy map over the arid areas of Algeria, Libya, and Tunisia in North Africa at 30 second (about 1 km) and 2 minute (about 4 km) spatial resolutions. The MODIS albedo data are from 7 spectral bands and 3 broadbands during dust‐free seasons and the emissivity data are derived from a linear combination of the waveband emissivities of the ASTER five thermal infrared channels. Both albedo and emissivity data in the study region show similar considerable spatial variability, larger than assumed by most climate models, and such variability is related to the surface types (sands, rock, and soil orders). Emissivity over bare soils exhibits statistically significant correlations with albedos at both broadbands and most of spectral bands and decreases linearly with albedos. Albedo and emissivity are more strongly correlated with each other than either is to the surface types, apparently because of their higher resolution either spatially or in surface mineralogy. This paper provides guidance for the possible inclusion of such correlation to specify albedo and emissivity in climate models.