摘要
在气候变化和城市化背景下,城市暴雨的局部特征愈发明显,而降雨监测和预报数据空间分辨率难以满足空间分布描述要求,造成城市洪涝模拟和预测结果存在不确定性。本文选择深圳市城区的3个流域,基于118场实测降雨数据,通过逐步增大网格尺寸以达到降低降雨空间分辨率的效果,同时以流域边界作为限制,保证流域内面平均雨量不变,然后将不同空间分辨率的降雨数据分别作为城市洪涝模型的输入条件,对流域出口断面的洪水过程进行模拟计算,每场降雨得到6种不同空间分辨率下的洪峰流量。结合降雨中心、流域几何中心等空间特征参数,分析降雨空间分辨率对流域洪峰的影响。研究结果表明,针对118场实测降雨,随着降雨数据空间分辨率逐渐降低,3个流域的出口断面的洪峰变化幅度逐渐增大;如果忽略了流域内部降雨数据的空间分布差异,洪峰变化幅度和方向与降雨中心和流域几何中心的空间关系具有相关性,降雨中心在流域几何中心上游方向的距离越大,洪峰降低的幅度越大。本文基于3个城市流域得到了相似的研究结论,研究方法可为城市流域洪涝模拟提供借鉴,研究结果可为河道洪水风险评价提供参考。
Due to climate change and urbanization, rainstorms are becoming more and more frequent and highly unevenly distributed in urban areas. However, it is difficult to have sufficient monitoring data for rainfall events because of insufficient installments of monitoring stations. Usually, the spatial resolution of meteorological forecast data is still coarse, which leads to the low accuracy of simulation and prediction results from urban flood models. Therefore, it is necessary to improve the spatial resolution of rainfall data to enhance the accuracy of urban flood simulation. In this paper, three catchment basins in Shenzhen River Basin are selected. Analytical data are extracted from 118 rainfall events lasting no less than 5 minutes from 31 meteorological stations within and around the study area during 2018—2020. The discrete observation data from meteorological stations are interpolated into continuous grids. According to the drainage zoning area, the grid size is initially set as 200 m×200m.The gridded data is then aggregated into 400 m×400 m, 800 m×800 m, 1600 m×1600 m, 3200 m×3200 m, and6400 m × 6400 m to achieve coarser spatial resolution rainfall datasets. The basin boundary is used during the aggregation to ensure that the average rainfall in the basin remains constant. The gridded rainfall data at different spatial resolutions are used as the input of an urban flood model to simulate the flooding processes of outlet sections in three watersheds. The model results of three watersheds are compared finally. By comparing the changes of flood peak at the outlets of each basin, the influence of rainfall spatial resolution on river flood peak is further analyzed by combing the spatial parameters such as rainfall center and basin center. The results of three watersheds show that for 118 rainfall processes, with the decrease of spatial resolution, the amplitude of flood at the watershed outlets gradually increases. When rainfall is evenly distributed in the whole basin, the variation ranges of flood peaks in the three basins are 5.04%, 8.73%, and 7.11%, respectively, compared to the rainfall data with 200m × 200 m grid size. The influence of spatial resolution is strongly correlated with the relationship between rainfall center and watershed geometric center, which strongly relates to the direction from watershed geometric center to watershed outlet. The research provides a reference for improving the accuracy of urban flood models by involving the variable of rainfall, which enable researchers to better assess the risk of river floods.
作者
刘业森
刘媛媛
李敏
李匡
LIU Yesen;LIU Yuanyuan;LI Min;LI Kuang(China Institute of Water Resources and Hydropower Research,Beijing 100038,China)
出处
《地球信息科学学报》
CSCD
北大核心
2022年第7期1326-1336,共11页
Journal of Geo-information Science
基金
国家自然科学基金项目(52009147)。
作者简介
刘业森(1980一),男,山东临沂人,博士,高级工程师。从事防洪减灾研究。E-mail:liuys@iwhr.com;通讯作者:刘媛媛(1978一),女,天津人,博士,正高级工程师。从事防洪减灾研究。E-mail:liuyy@iwhr.com。
