A viewing-angle dependent split-window method for retrieving land-surface temperatures from space

The authors propose a generalized split-window method for retrieving land-surface temperature (LST) from AVHRR data. Accurate radiative transfer simulations show that the coefficients in the split-window algorithm for LST must depend on the viewing angle, if they are to achieve a LST accuracy of about 1 K for the whole scan swath range (±50.3° from nadir) and for the ranges of surface temperature and atmospheric conditions over land, which are much wider than those over oceans. The coefficients in the split-window algorithm also vary with atmospheric column water vapor and boundary temperature. The column water vapor and boundary temperature can be estimated from HIRS/2 data or MODIS atmospheric sounding channels data. The authors obtain these coefficients from regression analysis of radiative transfer simulations, and they analyze sensitivity and error by using results from systematic radiative transfer simulations over wide ranges of surface temperature and emissivities, and atmospheric water vapor abundance and temperatures. This method is more suitable for retrieving LST from EOS´s MODIS data