2022年四川省复杂地形下持续性极端高温特征与模式误差分析

Characteristics and Model Error Analysis of Persistent Extreme Heat under Complex Terrain of Sichuan Province in 2022

2022年8月四川省持续性极端高温天气过程范围广、强度大且持续时间长,全省有74.8%的站点打破近70年历史同期极值。本文选取四川地区2022年8月逐时2 m气温实况站点和历史同期数据,结合EC、CMA-GFS及CMA-MESO模式的2 m气温预报数据,分析了此次极端高温天气特征及预报误差。结果表明:(1)受地形影响,最高气温极值呈东高西低的分布特征;(2)受热岛效应影响,最高气温超历史极值较多的站点主要集中在盆地西部龙泉山脉附近;(3)3个代表站的最高气温平均值高、距平大、高温持续时间长,该时段的累计降水量明显低于历史同期平均值且降水日数显著偏少;(4)3个模式对于最低气温的预报准确率明显高于最高气温,而最优模式的高温预报准确率仅39.1%;(5)EC模式的预报优势主要在盆地低海拔站点,CMA-MESO模式在陡峭地形区域的预报效果要优于EC模式;(6)对于最高气温出现日期预报,EC模式在盆地和攀西地区效果更佳,CMA-GFS和CMA-MESO模式在川西高原效果更优。

In August,2022,the persistent extreme heat weather process in Sichuan Province was wide in scope,strong in intensity and long in duration.There were 74.8%sites in the province that broke the extreme value in the same period of nearly 70 years.Based on the hourly 2m temperature data of Sichuan in August 2022,the historical data of the same period,the 2m temperature forecast data of EC,CMA-GFS and CMA-MESO models,the characteristics and forecast error of this extreme heat weather process were analyzed.The results show that:(1)Affected by the terrain,the maximum temperature was high in the east and low in the west.(2)Affected by the urban heat island effect,the stations with the maximum temperature exceeding the historical extreme value mainly were concentrated in the west of the basin near the Longquan Mountains.(3)The average maximum temperature of the three representative stations was high,the anomaly was large,and the duration of high temperature was long.The accumulated precipitation in this period was obviously lower than the historical average value of the same period,and the number of precipitation days was less.(4)The accuracy of the three models for the minimum temperature forecast was significantly higher than that of the maximum temperature forecast,while the accuracy of the high temperature forecast of the optimal model was only 39.1%.(5)The forecasting advantages of EC model mainly lay in the low-altitude stations of the basin,while CMA-MESO model was better than EC model in some places of steep terrain.(6)For the maximum temperature forecast date,EC was the best for the basin and Panxi region,while CMA-GFS and CMA-MESO were the best for the West Sichuan Plateau.