新疆昌吉州短时强降水时空分布与环境场特征分析
Analysis of Spatiotemporal Distribution and Environmental Field Characteristics of Short-Time Heavy Rainfall in Changji, Xinjiang
中文摘要：
利用新疆昌吉地区国家基本气象站和区域自动气象站逐小时降水资料，分析了2015—2019年汛期昌吉地区短时强降水的空间分布和月、日变化特征，研究了短时强降水发生的环境场和中尺度条件，结果表明：昌吉地区短时强降水因受海拔和地形影响，分布极不均匀，山区降水频次大于平原，东部大于西部地区；≥10 mm/h、≥20 mm/h的短时强降水6月发生频次最高，范围最广，从日变化来看，14—17时（北京时）是高发时段，占比26%；短时强降水影响系统可分型为西西伯利亚低槽、西北气流及中亚低槽，中亚低槽型占比最高，达60%，各型对应的中尺度环境要素各有差异，且各影响系统出现频次及时间分布规律均不同；对短时强降水过程的探空曲线进行了分析，初步构建了基于CAPE、LI、静力稳定度及垂直风切变、地面Td等的短时强降水临近预警阈值，并利用2021—2022年探空资料对其进行了检验，结果展示了较好的潜势预报效果。
中文关键词：
短时强降水，时空分布，中尺度环境场，探空阈值
KeyWords：
short-time heavy rainfall, spatiotemporal distribution, mesoscale environmental field, sounding threshold
Abstract：
Using the hourly precipitation data of national basic meteorological stations and regional automatic weather stations in Changji, Xinjiang, the spatial distribution as well as monthly and daily variation characteristics of short-time heavy rainfall in Changji during the flood season from 2015 to 2019 were analyzed. Moreover, factors such as environmental field characteristics and mesoscale conditions were studied. The research results illustrate the uneven distribution of short-time heavy rainfall in Changji because of the altitude and topography factors, with higher rainfall frequency over the mountainous areas than the plains and over the east than the west; Short-time heavy rainfall≥10 mm/h and≥20 mm/h occurs most frequently and covers the widest areas in June. In terms of the daily variation of rainfall, the probability of occurrence is greatest between 14: 00 BT and 17: 00 BT, accounting for 26% of the total. The influencing weather systems of short-time heavy rainfall can be categorized into three types: the West Siberia low trough, the northwest airflow, and the Central Asian low trough, among which the Central Asian low trough accounts for the highest proportion of 60%. The corresponding mesoscale environmental elements of each type vary from each other, and the frequency and temporal distribution patterns of each influencing system are different. The analysis of the sounding curves for short-time heavy rainfall processes has been conducted, and based on CAPE, LI, static stability, vertical wind shear, and ground Td, a preliminary warning threshold for short-time heavy rainfall nowcasting has been established. It was tested using sounding data from 2021 to 2022, and the results showed satisfactory potential forecasting effect.