Abstract:
The experiments were carried out to evaluate the simulations of the four-stream radiative transfer scheme within the vegetation canopy. The numerical results by use of vegetation canopy field observation of Chinese Zhejiang university and two models indicate that the simulations modeled by the two-stream and the four-stream models are mostly consistent in the visible band with small leaf scaterring. The simulations of two models are close to canopy albedo observation in this band. This indicates that the two-stream model can simulate the canopy albedo very well and the improvement of four-stream model is limited. The results also show that the albedo of the canopy modeled by the four-stream model is greatly improved than that of the two-stream model in the NIR band. To evaluate the simulations of the four-stream model for solar radiative flux reflected by land surface in land surface model, the four-stream model and the two-stream model were coupled into land surface process model. Two numerical experiments were carried out by use of BERMS open site and BERMS forest site observation in Canada from the Second Snow Model Intercomparison Project. The results indicate that the simulated solar radiative flux reflected by land surface for four-stream model is closest to observation beyond three radiative schemes coupled into land surface process model. The results proved the four-stream radiative transfer scheme can gain access to accurate canopy albedo. The tests indicate that the simulation of the land surface process model coupled four-stream model is the best among other radiative transfer models.