Analysis on the Extremity Feature and Forecast Error of Persistent Rainfall During the 2023 Wheat Harvest Period in Henan Province
Based on multi-source observations,multi numerical model products as well as subjective and objective forecasts,this paper analyzes the extremity feature of the persistent rainfall from May 20 to June 4,2023,and evaluates the subjective and objective forecasts.The results show that the accumula-ted precipitation anomaly percentage in Henan Province from May 20 to June 4 was averaged to be 170.3％.The accumulated rainfall of 17 stations ranked the first in the same period of history.The per-sistent rainfall process lasted for 11 days in Henan Province from May 25 to June 4,ranking the second in history.The west ridge point of the subtropical high at the 500 hPa mean field in May 25-30,2023,was 33 longitudes further westward than the climatological state,while the geopotential height over Henan was 160-200 gpm higher than the climatological state.Change in the moving direction of the precipitation system caused by the variation of the mid-level airflow was the main reason for the missing forecast of the extremely severe precipitation in western Henan.The forecast errors of models for the Super Typhoon Mawar and subtropical high directly caused the rain band to deviate to the south,which further led to the low scores of the rainfall forecasts above the rainstorm level in each numerical model.Regarding the im-pact mechanism of terrain in western Henan on wind field,it is more complex,needing in-depth diagno-sis and analysis to obtain objective conclusions.
万方数据
维普
