Evaluation and Correction of Rainfall Forecast by WRF Model in the Upper Reaches of the Yangtze River

The upper reaches of the Yangtze River is an important part of the Yangtze River Basin, which concentrates most of the water energy resources. It is meaningful to carry out high-accuracy rainfall forecast in the basin, which can help extend forecast lead time, improve the forecast accuracy of runoff forecast, and provide important decision information for flood control and disaster reduction. To improve the accuracy of rainfall forecast in the watershed, different combination schemes of microphysical processes, boundary layers, and cumulus convection parameterization scheme combinations in the WRF model were evaluated by TS score, mean absolute error and Brier score. AR model was introduced to correct the rainfall prediction results. The results show that the WRF model has the highest accuracy of rainfall forecast when the microphysical process scheme, boundary layer parameterization scheme and cumulus convection parameterization scheme are WRF single-moment 3-class scheme, Yonsei University scheme and New Kain-Fritsch scheme respectively. The corrected rainfall forecast can partially correct the phenomenon of “staggered peak”, which make forecast accuracy better.