An Independent Method to Determine the Surface Roughness Parameter

Abstract

A technique for independent evaluation of surface roughness length has been suggested. This approach only uses mean wind speed and friction velocity data measured at a single level. It was checked at first by using the data of the Kansas Experiment. Inter-consistent Z_0 derived from 5.66m and 22.6m data has been obtained and compares well with that derived from wind profiles. The technique was applied for determining the Z_0 of the Gobi desert in the HEIFE area and was based on the sonic anemometer-thermometer data collected during 1988 Pilot Observation Period. The estimation has been repeatedly conducted by using the data collected in 1990 and again reached a value of Z_0, which is also in good argeement with the value derived from wind profiles. The estimation of surface roughness for the Gobe desert is between 1.1×10^-3m to 1.5×10^-3m. The method presented here for roughness estimation has the advantage of determining Z_0 with simultaneous flux measurements, and without need for wind profile data.