摘要:
以新中国成立以来北京地区发生单日最大降雨的2012年“北京7 ·21暴雨事件”作为研究对象,采用热带降雨观测计划(tropical rainfall measuring missio,TRMM)降雨数据、气象观测降雨数据和中分辨率成像光谱仪(MO-DIS)的地表温度(land surface temperature,LST)产品,利用空间插值、空间降尺度、精度评价及相关分析等方法分析北京7月21日暴雨的时空分布特点,定量研究城市“热岛-雨岛”时空响应关系.结果表明:从空间分布来看,强降雨发生北京南部;从TRMM的3h降雨数据来看,随着时间推移最强雨带自西向东推进;经气象数据验证,降尺度的TRMM 3B42数据精度有所提高;LST对暴雨的影响表明热岛与雨岛在空间分布上存在一致性,且在雨强最大时段两者相关性最好.
Abstract:
In this paper,the authors selected July 21,2012,the biggest rainfall day since the founding of People's Republic China in Beijing,as the study target.The rainfall data from both Tropical Rainfall Measuring Mission (TRMM) and meteorological observations and MODIS LST products were mainly used to study the spatiotemporal distribution of rainstorm and the relationship between urban heat island (UHI) and urban rain island (URI).The spatial interpolation,spatial downscaling,accuracy assessment and correlation analysis were used in the study.Some conclusions have been reached.Firstly,the heavy rainfall area was located mainly in southern Beijing.The rainfall process moved from west to east,as shown by tracking the rainfall maxima of 3 h TRMM data.Secondly,the accuracy of TRMM data was improved by downscaling,as evidenced by the fact that the correlation between TRMM data and observational data was improved and RMSE decreased simultaneously.Finally,the spatial distribution of URI is consistent with UHI and the correlation between the two can produce optimal result in the maximum rainfall periods.
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