Improvement of surface process for application of a NWP system

Abstract

In order to apply a regional NWP (numerical weather prediction) system to Japan, two submodels are developed to refine the interaction between laiiduse and atmosphere. One is developed to estimate solar radiaticn using the relative humidity profile in the atmosphere, and the other to deal with the heterogeneity of landuse based on flux-equivalence concept. Some other aspects of this system are alsorevised for application in Japan. Incorporating the refinement with the NWP system, two numerical experiments are carried out in Tsurumi riverbasin and central Japan, respectively. The idealized storm case in Tsurumi riverbasin indicates the noticeable effect of surface process to rainfall in a small-scale riverbasin, and the case in central Japan shows the prediction performance of this system inmountainous region.