Topographic effects on spaceborne radiometric observations and possible correction strategies

A numerical simulator of satellite microwave radiometric observations of mountainous scenes, developed in a previous study, is used to predict the relief effects on the measurements of a spaceborne radiometer. For this purpose, the trends of the error due to topography versus the parameters representing the relief have been analyzed for a test case concerning a mountainous area in the Alps by assuming bare soil and considering L- and C-bands. The results have revealed that the error in satellite microwave radiometric observations is particularly correlated to the mean value of the height and of the slope of the radiometric pixel, as well as to the standard deviation of the aspect angle and of the local incidence angle. A regression analysis has been applied to estimate the error as a function of the parameters representing the relief, using the simulator to build training and test sets.