Land surface skin temperature climatology: benefitting from the strengths of satellite observations

Surface skin temperature observations (T_skin), as obtained by satellite remote sensing, provide useful climatological information of high spatial resolution and global coverage that enhances the traditional ground observations of surface air temperature (T_air) and so, reveal new information about land surface characteristics. This letter analyzes nine years of moderate-resolution imaging spectroradiometer (MODIS) skin temperature observations to present monthly skin temperature diurnal, seasonal, and inter-annual variations at a 0.05° latitude/longitude grid over the global land surface and combines these measurements with other MODIS-based variables in an effort to understand the physical mechanisms responsible for T_skin variations. In particular, skin temperature variations are found to be closely related to vegetation cover, clouds, and water vapor, but to differ from 2 m surface T_air in terms of both physical meaning and magnitude. Therefore, the two temperatures (T_skin and T_air) are complementary in their contribution of valuable information to the study of climate change.