基于遥感降水产品的西南地区降水时空动态分析

Analysis of Spatiotemporal Dynamics of Precipitation in Southwest China Based on Remote Sensing Precipitation Products

[目的]探究遥感降水产品在西南地区的适用性,揭示区域降水时空特征,为西南地区旱涝灾害评估及水资源利用等提供科学参考依据。[方法]首先结合西南地区内100个地面气象站点降水数据,从多年平均和年际两种时间尺度以及气象站点空间尺度评价了2001—2019年TRMM降水产品和GPM降水产品的适用性,然后基于优选的降水产品,采用变异系数法、Theil-Sen Median趋势分析耦合Mann-Kendall显著性检验方法及Hurst指数法进行降水时空变化及其可持续性分析,并预测了未来降水趋势。[结果](1)GPM,TRMM在西南地区均表现出较好的一致性和适用性,虽然都存在一定的高估现象,但GPM的降水空间细节表征能力优于TRMM,在整体上更接近实测数据。(2)19年间西南地区整体降水波动变化并不突出,主要表现出较低波动变化和中等波动变化,共占全域的87.54%;近19年西南地区降水变化趋势整体上表现为增加,降水增加区域占全域的83.71%,降水变化趋势以弱(50.38%)、中(24.30%)持续性为主;未来西南地区62.24%的区域降水趋势将持续增加,主要分布在西南地区中部和北部地区,13.23%的区域降水趋势将持续减少,主要分布在云南中部和四川西南部地区。[结论]GPM比TRMM更适合表征西南地区的降水特征,能有效用于开展降水的时空动态分析。

[Objective] The aims of this study are to explore the applicability of remote sensing precipitation products in southwest China,to reveal the spatial and temporal characteristics of precipitation in Southwest China,and to provide scientific references for the assessment of droughts and floods in southwest China and the utilization of water resources.[Methods] Firstly,combined with precipitation data from 100 ground-based meteorological stations in the study region,the applicability of TRMM and GPM precipitation products were evaluated on both the multi-year average and inter-annual scales,as well as the meteorological station scale.Subsequently,based on the preferred remote sensing precipitation product,the coefficient of variation method,Theil-Sen median trend analysis coupled with Mann-Kendall significance test and Hurst exponent were adopted to analyze spatiotemporal changes of precipitation and assess their sustainability.Moreover,our effort predicted the precipitation trends in the future.[Results](1) Both TRMM and GPM products demonstrated good consistency and applicability in southwest China,albeit with some overestimation.However,compared with TRMM,GPM displayed a higher spatial resolution and better data quality,which was overall closer to the measured data.(2) Precipitation in southwest China had experienced low and moderate fluctuations over the past 19 years,with 87.54% of the region.The trend for precipitation changes in this region had mostly been increasing(83.71%),mainly weak to moderate sustainability(50.38% weak,24.30% moderate).The prediction for future precipitation trend as a whole suggested a general increase in precipitation,with 62.24% of the region showing increasing trends,mainly in the central part of the study region,and 13.23% showing trends,mainly in the central Yunnan and southwestern Sichuan regions.This effort provided valuable insights for decision-making related to agricultural production and water resources management in southwest China.[Conclusion] GPM is more suitable than TRMM to characterize the precipitation characteristics in southwest China and can be effectively used to carry out spatiotemporal dynamic analysis of precipitation.