| 摘要: |
| 该文利用NCEP1°×1°再分析资料、常规和非常规观测资料、全球及中尺度数值模式产品对2018年7月4—6日出现的一场持续性暴雨个例展开分析，重点分析了持续性暴雨的天气成因、数值模式产品的检验评估以及相关的订正技术。结果表明，此次持续性暴雨过程是华南地区维持稳定少动的高压环流影响下，西风带短波槽和北方南下的东西向横切变受高压环流阻挡长时间维持在贵州地区，切变北侧南下的干冷气流和高压环流西北侧北上的暖湿气流交汇形成的持续性暴雨，中低层切变辐合是主要的动力强迫，华南地区高压后侧的西南暖湿气流在降水前夕和降水过程中输送了充沛的水汽和不稳定差动平流，为暴雨的持续发生提供了较好的水汽和能量条件。选取了3家数值模式（EC、华东、华南）进行了检验评估，模式降水产品落区和量级与实况偏差较大，华东模式降水产品在本次过程中有一定参考价值，EC模式7月4日20时—6日20时的风场结构预报准确，预报员充分利用该产品对这一时间段降水落区和量级进行了正技巧订正，但7月6日20时—7日20时对中低层的风场结构预报和实况有较大偏差。充分利用数值模式产品和实况当前时段的检验评估结果，采用外推法对未来时段的数值模式产品进行适当订正，能有效提高暴雨预报的精准度。 |
| 关键词: 贵州；持续性暴雨；预报误差；订正 |
| DOI： |
| 投稿时间：2019-10-13 |
| 基金项目: |
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| The Cause of a Persistent Rainstorm and Forecast Error Analysis in Guizhou |
| YANG Xiuzhuang,LI Gang,ZHOU Mingfei,DU Xiaoling,LI Li |
| (Guizhou Provincial Meteorological Observatory, Guiyang 550002 , China) |
| Abstract: |
| A case of persistent rainstorm process, occurred on July 4-6, 2018, was analyzed based on the 1°×1° reanalysis data of the NCEP/NCAR, conventional and unconventional observation data, global and mesoscale numerical model products. This analysis was focused on the cause, inspection and evaluation of numerical model products and related correction techniques. The results show that the persistent rainstorm taken place when the westerlies and the east-west shear are blocked by high-pressure circulation staying long in Guizhou. The mid-lower shear convergence was the main dynamic forcing. The southwest warm-humid airflow along the back side of thigh-pressure circulation provide abundant water vapor and unstable energy condition for the heavy continuous rain. Three numerical models (EC, East China, South China) were selected for inspection and evaluation. Compared with the real situation, the deviation of the drop and magnitude of the numerical model products was larger. The East China model precipitation products were of reference value in this process. The wind field forecast of EC mode was accurate from 20∶00 on the 4th to 08∶00 on the 6th in July. The forecaster corrected the drop and magnitude of precipitation, making full use of the products of EC mode during this period. But wind field forecast of EC mode was quite different from the actual situation in the middle and lower levels at 20∶00 on the 6th and 7th in July. Through the test, the extrapolation method to properly correct the numerical model products in the future can effectively improve the accuracy of the rainstorm forecast. |
| Key words: Guizhou； persistent rainstorm； forecast error； correction |
