An independently derived excess resistance was used to modify the classical relationship between surface-air temperature difference and sensible heat flux. The modified relationship was used to estimate sensible heat flux using radiometric surface temperature, air temperature, and wind speed measured at a sparse prairie site during the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) 1987 and FIFE 1989. Using the classical relationship, the mean sensible heat flux is overestimated by 141 W m-2 compared to an underestimate of only 21 W m-2 using the relationship including the excess resistance, also the root-mean-square error decreased from 63 to 26 W m-2. ¿ American Geophysical Union 1995