An algorithm to determine the sensible heat flux from simple field measurements (wind speed, air and ground temperatures) has been developed. It provides a direct solution, in parametric form, which can be displayed graphically or tabularly. This method has an advantage over the previous iterative solution in that the computation is fast. It also provides a clearer understanding of the drag coefficient, its variation and response to different conditions. A simple example illustrated that at low wind speeds the drag coefficient cannot be treated as a constant. Both the computational speed and analysis of the drag coefficient can be important for remote-sensing applications involving thermal scanner data.