A comparative analysis of satellite-observed visible reflectance and 37 GHz polarization difference to assess land surface change over the Sahel zone, 1982–1986

摘要

Applicability of visible reflectance to monitor land surface change particularly for arid and semi-arid regions has been studied fairly extensively. Visible reflectance over the Sahel zone from January 1982 to December 1986 has been derived from observations by the advanced very high resolution radiometer (AVHRR) on board the NOAA-7 and NOAA-9 satellites and compared against concurrent observations of 37 GHz polarization difference by the scanning multichannel microwave radiometer (SMMR) on board the Nimbus-7 satellite. Analysis of radiative transfer models suggested a high correlation to exist between these two sets of observations, and the observed spatial and temporal patterns of these data sets did show an overall high correlation. Land surface change resulting from the 1984 drought affected both of these data sets, but not in identical fashion. The present study suggests that potentially new information about physical and biophysical characteristics of the surface could be obtained by synergistic use of these two data sets.