Technical Abstract: The significance of soil surface roughness on the relationship between radar backscatter and surface soil moisture has been recognized for some time. Several recent advances have begun to isolate and quantify roughness effects. These results suggest that it may be possible to estimate roughness directly using multipolarization radar data, that classical solutions to modeling the roughness effects do apply, and that surface soil random roughness appears to be the dominant parameter needed in modeling. Since current and near future satellite radar systems operate at only a single frequency and polarization, it will be necessary to provide an independent estimate of surface roughness if soil moisture is to be derived from radar data. Extensive research conducted primarily in the field of soil erosion to relate soil roughness to other variables may provide a solution. In addition, data sets available from the years of previous ground and aircraft experimentation could be applied. If the information necessary for defining the categories and conditions described in these previous studies can be determined using readily available ancillary data, ie., NDVI, crop calendar, etc., it might be possible to develop global roughness data.