Global Emissivity Distribution from 2003 to 2007 and Contributors to its change in the Iranian Plateau, the La Plata and the Indus River Basin

Land surface emissivity is known to be affected by land surface cover, surface roughness, and soil moisture. In this study we used land surface emissivity data from NASA's Advanced Microwave Scanning Radiometer for Earth Observing Systems (AMSR-E) for 2003 To 2007, to detect areas of significant emissivity change and identified its potential causes. Data distribution of annual emissivity averages on a global scale revealed that the western coastlines of the continents, deserts, and the polar areas showed the lowest emissivity values while the higher emissivity values were concentrated in large cities, heavily forested areas, and large mountain ranges. At the regional scale, three regions showed statistically significant annual change values at the 99% confidence interval, which included the Iranian Plateau, the La Plata basin, and the Indus Basin. In the La Plata River Basin, areas of significant negative emissivity change (≤-0.0156) were noted, which are associated with deforestation, while the areas of significant emissivity gain (≥0.0165) were concentrated in floodplains. In the Indus Basin and Iranian Plateau, the significant negative emissivity change was associated with the mountainous topography.