Estimation of the cover and management factor for modeling soil erosion using remote sensing.

The cover and management factor(C) of the Universal Soil Loss Equation(USLE) is difficult to be estimated over broad geographic areas where meteorology and soil erosion are poorly monitored.This paper presents a new approach to estimate C factor based on multi-temporal images of Landsat TM/ETM and a weather generator.The linear spectral unmixture algorithm was adopted to calculate the fractional abundance of ground cover,from which the potential soil loss ratio(PSLR) was estimated.The weather generator(CLIGEN) was used to simulate historical rainfall events and compute the distribution of rainfall erosivity indices.The annual C factor was finally estimated by means of weighting PSLR with the proportion of rainfall erosivity indices.The proposed method was applied to the upstream area of the Chaohe River for validation.The results showed that the estimated C values appropriately responded to the vegetation abundance and land use types,and the estimated soil loss fitted well to the observed records.