Evaluation of satellite rainfall estimates over the Lake Tana basin at the source region of the Blue Nile River
Evaluation of satellite rainfall estimates over the Lake Tana basin at the source region of the Blue Nile River
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青尼罗河源区塔纳湖盆地卫星降雨估算评估
DOI：
10.1016/j.atmosres.2018.05.009
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发表时间：
2018
影响因子：
5.5
通讯作者：
K
中科院分区：
文献类型：
--
作者：
Fenta;AA.;Yasuda;H.;Shimizu;K.;Ibaraki;Y.;Haregeweyn;N.;Kawai;T.;Belay;AS.;Sultan;D.;Ebabu;K
卫星降雨量估计(SRE)已经成为几种应用的降雨量数据的替代来源。然而，SRE的准确性可能因地区而异，必须在当地基础上进行评估。这项研究评估了埃塞俄比亚西北部塔纳湖盆地三个SRE的准确性。该盆地的特点是地形复杂，既有低地也有高地。这三个小岛屿发展中国家是利用卫星数据和地面观测的气象学热带应用(TAMSAT)、气候灾害红外降水与站(CHIRPS)和非洲降雨气候学(ARC)。在1995年至2010年期间，在每日、Dekadal(10 天)、每月和季节周期的点到像素的基础上，将SRE与低地和高地地区的测量结果进行了比较。结果表明，三个SRE都低估了降雨事件，但TAMSAT较好地捕捉到了这两个地区的降水发生。ARC比TAMSAT和Chirps更好地估计小雨速率(1-5 mm d−1)；然而，所有SRE都明显低估了中雨和大雨速率(≥10 mm d−1)。TAMSAT和CHIRPS在日、日和月的时间尺度上对降雨量进行了相当好的估计(高效率、低随机误差和偏差10%)，而ARC在任何时间尺度上的表现都不令人满意(高随机误差、低效率和偏差20%)。在季节尺度上，CHIRPS对次雨季(3-5月)降雨量的估计比ARC和TAMSAT更好，而TAMSAT在主雨季(6-9月)比CHIRPS和ARC都要好。总体而言，SRE的降雨探测能力和降雨量估计均好于低地，累积降雨量估计值倾向于随着积分时间的增加而改善(即从每日总数到季节总数)。
Satellite rainfall estimates (SREs) have become alternative sources of rainfall data for several applications. However, the accuracy of the SREs is likely to vary from region to region and must be evaluated on a local basis. This study evaluated the accuracy of three SREs for the Lake Tana basin in northwestern Ethiopia. This basin is characterized by complex topography comprising both lowlands and highlands. The three SREs were the Tropical Applications of Meteorology using SATellite data and ground-based observations (TAMSAT), the Climate Hazard Infrared Precipitation with Stations (CHIRPS), and the Africa Rainfall Climatology (ARC). The SREs were compared with gauge measurements in lowland and highland regions during the period 1995–2010 on a point-to-pixel basis at daily, dekadal (10 days), monthly, and seasonal periodicities. The results show that the three SREs underestimated rainy events, but TAMSAT captured rainfall occurrence relatively well in both regions. ARC better estimated light rain rates (1–5 mm d−1) than did TAMSAT and CHIRPS; however, all the SREs markedly underestimated moderate and heavier rain rates (≥10 mm d−1). TAMSAT and CHIRPS estimated the amount of rainfall reasonably well (high efficiency, low random errors, and bias <10%) at daily, dekadal, and monthly time scales, whereas ARC did not perform satisfactorily (high random errors, low efficiency, and bias >20%) at any time scale. On a seasonal scale, CHIRPS estimated the secondary rainy season (March–May) rainfall better than did ARC and TAMSAT, whereas TAMSAT outperformed both CHIRPS and ARC during the primary rainy season (June–September). Overall, the rainfall detection capabilities and rainfall amount estimates of the SREs were better over the lowlands, and the cumulative rainfall estimates tended to improve with increasing integration time (i.e., from daily to seasonal totals).