Ground heat flux determination according to land skin temperature observations from in situ stations and satellites

Due to rapid progress in the development of remote sensing techniques, skin temperature can now be observed with global coverage from satellites. This study derives an equation for utilizing skin temperature measurements to determine ground heat flux. This equation is verified at the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) campaign site and four Fluxnet sites. A preliminary monthly global dataset of ground heat flux with 1 degrees resolution, covering the years 1984-95, is derived based on skin temperature observations obtained via satellite. It shows that the seasonal variation of ground heat flux over land can be determined at 1.5 months ahead by observing the increasing rate of skin temperature, and that the variation increases from +/- 2 W m(-2) at the equator to +/- 20 W m(-2) at the poles. Over land, the resulting ground heat flux can be compared with that of the ERA-15 reanalysis, showing rms differences of about 4 W m(-2).