浙江东部GPM卫星数据捕捉降水事件要素能力研究与评价

Study and Evaluation on Capability of Precipitation Event Properties Captured by GPM Data in Eastern Zhejiang Province

为了系统研究GPM IMERG数据对降水事件要素(降水次数、降水历时、降水事件间隔、平均降水强度和总雨量等)的捕捉能力,选择椒江流域和富春江流域两个典型流域,在事件尺度上,通过与2014~2019年地面站点实测数据对比,评估了GPM数据对各降水事件要素及雨型的捕捉能力。结果表明,GPM IMERG数据在月雨量方面与地面实测数据有着较好的相关性,总体效果较好;但GPM数据对降水历时存在高估现象,对月平均降水强度的监测与地面数据的相关性不好,尤其是台汛期的高雨强降水事件,总体低估了降水事件的平均降水强度;从雨型曲线可看出,GPM IMERG数据较实测数据探测的降水事件存在更大的可变性,对小雨强降水的探测较为敏锐。

In order to systematically study the ability of GPM IMERG data to capture precipitation event properties(precipitation frequency, precipitation duration, precipitation event interval, average precipitation intensity and total rainfall), this paper selected two typical basins of Jiaojiang River Basin and Fuchun River Basin, and compared the measured data with the ground stations during 2014-2019 on the event scale to evaluate the ability of GPM data to capture precipitation event properties and storm patterns. The results show that the GPM IMERG data has a good correlation with the ground measured data in terms of monthly rainfall, and the overall effect is good. However, the GPM data overestimated the precipitation duration, and the correlation in terms of the monitoring of monthly mean precipitation intensity between GPM and the measured data was not good. Especially, the average precipitation intensity of heavy precipitation events in the typhoon season was generally underestimated. It can be seen from the storm pattern curve that the GPM IMERG data has greater variability in precipitation events than the measured data, and is more sensitive to the detection of light precipitation events.