The comparison of two models that determine the effects of a vegetation canopy on passive microwave emission

Two contrasting models are used to account for the effects of vegetation on microwave emission from the soil. These are: a simple model which requires two empirically derived parameters as input data (optical depth and single scattering albedo); and a complex discrete model which requires a detailed description of all of the components of the vegetation canopy. Both models account effectively for the vegetation, although the simple model takes a fraction of the computation time compared to the discrete model. However, t he simple model was fitted to the data, whereas the discrete model used mea sured parameters as input. In addition to predicting the microwave brightne ss temperature, the discrete model also calculates the optical depth and si ngle scattering albedo. These calculated values were in agreement with thos e fitted using the simple model. Therefore, it is suggested that the discre te model could be used to calculate the input parameters for the simple mod el.