北京地区景观城市化进程对暴雨过程的影响——以“7·21”暴雨为例

利用美国环境预测中心（NCEP）和美国国家大气研究中心（NCAR）等美国科研机构开发的气象模式WRF 3.8版本,采用北京地区不同时期的土地利用数据,选取影响北京的一次典型暴雨过程,应用包含多层城市穹顶模式的模式参数化方案对其进行模拟研究。从小时降水模拟结果来看,景观城市化区域（城市下垫面）的扩张使得暴雨持续更久,使用2010年土地利用数据模拟的2012年7月21日暴雨过程小时降水量大于16 mm的时长较使用1990年土地利用数据模拟的结果增加了1 h;从累积降水结果来看,使用2010年土地利用数据模拟的24 h累积降水大于150 mm的区域较使用1990年土地利用数据模拟的结果增加了1534 km ²。本文中模拟的逐小时降水与实际情况存在一定的差距,未来的工作会深入研究模式的参数化方案和降水产生的机理进而深入地研究景观城市化进程对暴雨过程的影响。进一步研究需针对城市人为活动产生的大气气溶胶粒子、景观城市化密度变化等因子,探究景观城市化对暴雨的可能影响。

The impact of the urbanization process on rainfall in Beijing:A case study of 7.21 rainstorm

This article used the Weather Research and Forecasting Model(WRF)version 3.8 and simulated rainfall event in the period of July 21 to 22,2012 in Beijing as a case study,with consideration of different land use and cover data.The rainfall event was simulated using a physical parametrization scheme that included a multi-layered city dome model.The results of the hourly and accumulative rainfall simulation indicated that the expansion of the urban area made the rainfall last longer and it also led to bigger affected area by the rainfall.Based on the simulated rainfall event,the duration of hourly rainfall of more than 16 mm increased by 1 h between 1990 test and 2010 test,and the area of accumulative precipitation exceeding 150 mm over 24 h increased by 1534 km^2 over the same period.Further research is needed to determine the possible impact of changes in atmospheric aerosol particles produced by human activities in the urban area and the changes in landscape urbanization density on rainfall.Identifying the effect of landscape urbanization in metropolitan areas on rainfall will improve countermeasures for prevention of urban flooding and waterlogging risk.Future research will focus on improving the simulation effect of the model on the precipitation process.There was some discrepancy between the simulated and actual hourly precipitation in this study.Future work will investigate the parametric scheme of the model and the precipitation mechanisms it uses.