长江上游卫星反演与再分析降水数据的适用性评估

为评估不同降水数据在长江上游的适用性,基于气象站点观测数据,采用多种评价指标,定量评估了卫星反演降水数据(IMERG-Final、GSMaP-Gauge)及再分析降水数据(ERA5-Land)在长江上游的应用精度,并分析了各降水数据在不同等级降水的误差结构。结果表明:3套降水数据均能准确捕捉流域降水东高西低的空间格局,与观测降水有着良好的相关性,且2015—2019年表现平稳,有可长期应用的潜力；各降水数据时间分辨率越高,误差相对越大,在流域地形变化剧烈的中部误差更大；对弱降水易错报高估,对强降水的低估随降水强度上升而加剧；两套卫星反演降水数据总体误差较小,适用性良好,IMERG-Final有更好的误差控制能力,GSMaP-Gauge对降水发生的识别更为准确；ERA5-Land明显高估流域降水,尤其在西南部地区。

Applicability evaluation of satellite and reanalysis precipitation products in upper Yangtze River Basin

In order to assess the applicability of different precipitation products in the upper Yangtze River Basin, based on meteorological station data, using multiple evaluation indicators, a quantitative assessment was conducted on the application accuracy of satellite retrieval(IMERG-Final and GSMaP-Gauge) and reanalysis (ERA5-Land) precipitation data in the upper Yangtze River Basin, and the error structures of different intensity precipitation in each dataset were analyzed. The results show that all three sets of products are able to accurately capture the spatial pattern of higher precipitation in the east and lower precipitation in the west of the basin, showing good correlation with observed precipitation and stable performance during 2015-2019, which indicates the potential of long-term application. Products with higher temporal resolution perform worse, larger errors occur in the central region with drastic changes in basin topography, and there is a tendency to overestimate weak precipitation and underestimate strong precipitation, with underestimation increasing with precipitation intensity. The overall errors of the two satellite products are small, with good applicability. IMERG-Final demonstrates better error control capability, while GSMaP-Gauge shows more accurate identification of precipitation events and ERA5-Land significantly overestimates basin precipitation, particularly in the southwest.