GPM降水资料在祁连山地区的适用性分析

Analysis of the applicability of GPM precipitation data in Qilian Mountain region

摘要:

西北地区是我国干旱最严重的地区之一,对该地区降水的研究有重要科学意义,高时空分辨率的GPM(Global Precipitation Measurement)卫星降水资料对西北地区观测资料稀疏复杂地形条件下降水过程的深入研究提供有益的科学补充。本文利用祁连山地区甘肃省境内的加密地面观测资料,采用TS(Threat Score)评分、一致性指数与CSI(Critical Success Index)等对GPM降水进行了客观评估。结果表明:(1)GPM资料能够表征祁连山地区不同季节降水的主要落区,同时该资料低估了弱降水区的量值,高估了强降水区的量值；(2)观测资料显示,祁连山地区形成小雨的频率最高,达85.95%,中雨、大雨和暴雨的频次较少,分别为12.04%、1.89%和0.1%；GPM资料探测结果与观测较为一致；(3)GPM资料也可以较好地表征祁连山地区降水的日变化特征,该资料能够较好捕捉到夏、秋季节降水主要集中在早晨和夜间的特征,冬季的效果最差。总体上看,GPM资料能够以较高的准确度探测西北复杂地形下的降水过程。[1]

Abstract:

Northwest China is one of the most serious drought areas in China, and the study of precipitation in this region is of great scientific significance. The high temporal and spatial resolution of the GPM (Global Precipitation Measurement) satellite precipitation data provides a useful scientific supplement to the in-depth study of the precipitation process in the Northwest China region under sparse and complex terrain conditions. In this paper, the intensive surface observations within Gansu Province in the Qilian Mountains region were utilized to objectively assess the GPM precipitation using TS (Threat Score) scores, consistency indices and CSI (Critical Success Index) etc. The results show that: (1) the GPM data can characterize the main fallout areas of precipitation in different seasons in the Qilianshan region, and at the same time, the data underestimates the amount of weak precipitation areas and overestimates the amount of strong precipitation areas; (2) the observation data show that the Qilianshan region has the highest frequency of forming drizzle, which is 85.95%, and the frequencies of medium rain, heavy rain and heavy rain are less frequent, which are 12.04%, 1.89% and 0.1%, respectively; The GPM data detection results are more consistent with the observations; (3) the GPM data can also well characterize the daily change of precipitation in the Qilian Mountain region, and the data can better capture the characteristics of summer and autumn seasons when precipitation is mainly concentrated in the morning and at night, and the effect is the worst in winter. Overall, the GPM data can detect the precipitation process under the complex terrain of Northwest China with high accuracy