安徽省近10年降水预报性能评估及应用对策

Evaluation of Precipitation Forecasts and Application Countermeasures in Anhui Province in Nearly 10 Years

对降水预报进行性能评估及应用对策研究可以更好地发挥降水预报在防汛抗旱中的决策支持作用。基于安徽省气象台近10年汛期(2007—2016年5月1日—9月30日)24~168h共7个预见期降水预报和地面降水观测资料,采用正确率、TS评分、概率统计、ROC曲线以及CTS等方法评估安徽省降水预报性能,并分析其在防汛抗旱中的应用对策。结果表明:(1)近10年中雨到暴雨量级降水预报性能逐步提高;降水预报性能随预见期缩短而逐步提升;降水预报总体性能随降水强度增加呈下降趋势;皖北平原降水预报性能优于皖南山区及大别山区;(2)降水预报与实况量级整体相差不大,存在过度预报现象且对强降水中心预报能力不足,但对于强降水过程仍有较好的指示意义。当预报有降水过程时,防汛抗旱要关注降水空间分布的不均匀性和不确定性;(3)长预见期降水预报不确定性大,短预见期降水预报可信度较大,尤其是短预见期的强降水过程以及转折性天气过程预报性能相对于长预见期有明显提高;在具体应用时要长中短预见期预报相结合,并根据最新降水预报进行防汛抗旱方案调整。分析结果表明降水预报可为防汛抗旱提供有价值的决策支持信息。

The evaluation of precipitation forecasts and corresponding researches related to application countermeasures can better play the role of precipitation forecasts in flood control and drought relief.Based on the precipitation forecasts with 7 lead times(24~168 h)and the observation precipitation data in flood season during the period from 2007 to 2016,five evaluation methods(Percentage Correct,Threat Score,Probability Statistics,ROC curve,CTS)were introduced to estimate the precipitation prediction skill and analyze the application countermeasures in flood control and drought relief.The results indicate that:(1)the forecast skill of moderate rainfall and the above intensity increased gradually in the recent 10 years;the precipitation forecast performance was improved with the shortening of lead time,however,decreased with the increase of rainfall intensity;normally,the forecast skill in the plain area in north Anhui was better than that in southern mountain area of Anhui Province and Dabie Mountain area;(2)overall,even though the rainfall predictions were well consistent with observations,the over forecast and forecast deviation of strong precipitation center still existed;in aspect of heavy rainfall processes,precipitation forecasts were of strong indication significance;according to the above results,heterogeneity and uncertainty of the spatial distribution of precipitation should be concerned in flood and drought prevention operation;(3)compared to forecasts with long lead time which had great uncertainty,forecasts with short lead time were more reliable and had better performance in heavy precipitation processes and transition weather.In practical application,the combination of precipitation forecasts with different forecast periods and the latest forecasts was strongly suggested to beutilized to adjust the flood control and drought relief operation.All statistic results proved that the usability of precipitation forecast in flood season and the research results could be valuable reference of flood risk management and water resource distribution.