High Resolution Radar Accumulation Maps for Verification of WRF+VAR(National Radar Network)

摘要

@@ 1. Introduction A contemporary theme in numerical weather prediction (NWP) is the assimilation of radar observations of reflectivity and radial Doppler winds into convective scale models. As NWP is partly an initial value problem, there is some expectation that by assimilating high resolution observations the short term skill of model predictions should be increased. However there remains some question about the best way to determine quantitative precipitation forecasts (QPF) skill. Direct comparison of model accumulations to gauge networks or remotely sensed satellite or C-band radar areal accumulations is problematic as each observation type suffers from scale problems (e.g. Fabry et al. 1994), particularly at the scales associated with convective rainfall. In this work we use a high resolution X-band radar accumulation product, which overcomes some scale problems, to estimate the total precipitation falling into the catchment. This observation can then be compared to model accumulation above the catchment.