Comparison of Split-Window and Single-Channel Methods for Land Surface Temperature Retrieval from MODIS and AATSR Data

In this study, two different methods for retrieving the Land Surface Temperature (LST) from Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) and Envisat/Advanced Along Track Scanning Radiometer (AATSR) data are compared against a database of ground measured LSTs. These are the split-window (SW) and the single-channel (SC) methods. The SW method expresses LST as a combination of the brightness temperatures in the 11 iquestm and 12 iquestm channels with coefficients that can have local or global validity, depending on the way they are obtained. SC methods are based on the atmospheric radiative transfer equation. To solve this equation, convenient atmospheric temperature and water vapor profiles are required as inputs of a radiative transfer model. In this work we used three different sources of atmospheric profiles: local radiosoundings (LR) reanalysis model output (RM), and satellite-based profiles (SB). Results show that the SW method produces more accurate LST retrievals (plusmn0.5 K) than the SC method with the three profile sources used, of which the RM source yielded the best results (plusmn1.0 K).