Gyasi-Agyei Yeboah, Obuobie Emmanuel, Yu Bofu, Addi Martin, Yahaya Bashiru
School of Engineering and Built Environment, Griffith University, Nathan, Australia.
Water Research Institute, Council for Scientific and Industrial Research, Accra, Ghana.
Sci Rep. 2023 Oct 4;13(1):16702. doi: 10.1038/s41598-023-43075-0.
Thirteen satellite precipitation products (SPPs), re-gridded to 1 km resolution, were evaluated in terms of the structural similarity index (SSI) over the Pra catchment in Ghana. Three SPP scenarios were considered: Scenario one (S1) was the original SPPs; Scenario two (S2) was bias-corrected SPPs; and Scenario three (S3) was the better of S1 and S2 for each wet day. For each scenario, the best SPP was selected to constitute the 14th SPP referred to as the BEST SPP. Each SPP was evaluated in terms of SSI against the rain gauge rainfield for each wet day. For S1, the top three SPPs were TMPA, GSMAP and CMORPH; for S2, CMORPH, PERCCS and MSWEP were the top three; and for S3, CMORPH, PERCCS and TMPA came out on top in order of decreasing performance. Bias correction led to improvement in the overall SSI measure (SSIM) for 73% of wet days. The BEST SPP increased the SSIM of the best individual SPP by over 50% for S1, and over 30% for both S2 and S3. Comparing the BEST SPP of the three scenarios, S2 increased the SSIM statistic by 20% over that for S1, and SSIM was further improved by 4% for S3. It is highly recommended to use BEST SPP (S3) to generate the required 1 km × 1 km rainfields for the Pra, or other catchments around the world with a sparse rain gauge network, through conditional merging with rain gauge data as demonstrated.
对13种重网格化至1公里分辨率的卫星降水产品（SPP），在加纳普拉集水区，依据结构相似性指数（SSI）进行了评估。考虑了三种SPP情景：情景一（S1）为原始SPP；情景二（S2）为偏差校正后的SPP；情景三（S3）为每个降雨日中S1和S2里表现较好的那个。对于每种情景，选择最佳的SPP构成第14种SPP，称为最佳SPP。针对每个降雨日，依据SSI将每种SPP与雨量计降雨场进行评估。对于S1，排名前三的SPP是TMPA、GSMAP和CMORPH；对于S2，排名前三的是CMORPH、PERCCS和MSWEP；对于S3，CMORPH、PERCCS和TMPA按性能递减顺序位列前茅。偏差校正使73%的降雨日的整体SSI度量（SSIM）得到改善。最佳SPP使最佳单个SPP的SSIM在S1中提高了50%以上，在S2和S3中均提高了30%以上。比较三种情景的最佳SPP，S2使SSIM统计值比S1提高了20%，S3使SSIM进一步提高了4%。强烈建议使用最佳SPP（S3），通过如所示与雨量计数据进行条件合并，来生成普拉集水区或世界其他雨量计网络稀疏的集水区所需的1公里×1公里降雨场。
