深圳市“龙舟水”的时空特征及致灾风险分析

Spatiotemporal Characteristics of the“Dragon⁃boat Rain”in Shenzhen and Analysis of Its Disaster⁃inflicting Risks

为了解深圳“龙舟水”期间降雨时空分布及致灾风险,利用深圳市国家基本气象站长序列资料和高时空分辨率的区域自动气象站资料,开展了深圳市“龙舟水”降雨时空分布及精细至街道的强降雨致灾风险分析。研究结果表明:1953—2021年深圳“龙舟水”雨量和雨日均呈略减少趋势,但2000年以来雨强呈增强趋势;“龙舟水”期间降雨呈“前少后多”的特点,6月6—14日是“龙舟水”最集中时期。降雨空间差异性大,呈东多西少分布:东南部大鹏新区雨量最多,西部宝安、光明、南山最少;“龙舟水”期间短时雨强大,1和3 h雨量极值普遍超过50和100 mm,分别达到深圳暴雨橙色和红色预警信号发布标准;1、3、24 h雨量极值呈由东南(大鹏-盐田)、西北(宝安-光明)向中部逐渐减小的分布,东南沿海是“龙舟水”期间极端短时强降水和持续性强降雨叠加区。基于精细到街道的降雨积涝阈值,深圳北部和中部是龙舟水强降雨致灾高风险区,“龙舟水”强降水期间需重点防范。

To understand the spatiotemporal distribution of precipitation during the annual late-May through mid-June concentrated period of heavy rain,which is also known as the“Dragon-boat Rain”(to be referred to as the“DB rain”hereafterwards),this work uses the long series data from national basic stations and data with high spatiotemporal resolution from regional automatic weather stations in the city to analyze the spatiotemporal distribution of the DB rain and community-scale disaster-inflicting risks resulting from the intense rain.The results are shown as follows.For the years studied(from 1953 to 2021),both the amount of rain and the number of rainy days during the DB rain tend to decrease slightly but re-intensify since 2000.The DB rain is less frequent in the first half than in the latter half of the period with 6 to 14 June being the dates with the most concentrated amounts.The DB rain is much different spatially with more amount in the east than in the west of the city.The DB rain amount is the largest in the southeast Dapeng New District and the least in the western districts of Bao’an,Guangming and Nanshan.For much of the city,1-h and 3-h rain extremes are more than 50 mm and 100 mm respectively,meeting the thresholds for issuing the brown and red heavy rain warning alerts for Shenzhen respectively.1-h,3-h,and 24-h rain extremes tend to de-crease gradually from the southeast districts of Dapeng and Yantian and the northwest districts of Bao’an and Guangming to the central part of the city.Coastal parts in the southeast are the areas where extreme short-term intense rain is superimposed with persistent intense rain.Based on relevant thresholds for rain-caused floods at the community scale,it is known that the northern and central parts of Shenzhen are the areas of high risks with intense rain-inflicted disasters during the DB rain,which need to be implemented with con-certed preventive measures.