关键词: WRF模式, 2 m温度, 地形高度误差, 焚风, 水陆风

Abstract: The observation data of 123 stations in Shandong province from November 2017 to February 2018 was used to verify 2 m temperature forecast starting at 08:00 and 20:00,respectively based on the Weather Forecast and Research (WRF) model.The forecasting effects of hourly temperature at 2 m and the daily minimum and maximum temperatures were evaluated.The reasons for the large error at some stations were analyzed.The result shows that the accuracy of 2 m temperature forecasted from the WRF model starting at 08:00 is higher than that forecasted starting at 20:00.The forecasting effect in day-time is better than that at the night.The prediction effect in the northwest and peninsula region is better than that in the other region in Shandong province.The negative error rate of most stations is larger than the positive one.The forecasting effect of the daily maximum temperature is better than that of the daily minimum one.The terrain height error in the model is the main factor that makes a large positive error of 2 m forecasting temperature at Mountain Tai station.Two schemes based on temperature gradient are used to correct 2 m forecasting temperature at Mountain Tai station.After correction,the mean absolute error decreases generally.However,there is a negative effect in the correction in some forecasting cases when a single temperature gradient is used.The forecasting effect is more stable when using the temperature gradient changing with the forecasting time.Affected by the terrain height error in the model,the foehn cannot be simulated by the WRF model.When the foehn occurs in Taian station,very large negative errors of 2 m forecasting temperature occur.The difference of land type between the model and real situation is one of the most important reasons that make a large negative error of 2 m forecasting temperature at Xuecheng station at the night.

Key words: WRF model, 2 m temperature, Terrain height error, Foehn, Water and land breeze