Awange J L, Hu K X, Khaki M
School of Earth and Planetary Science, Spatial Science Discipline, Curtin University, Perth, Australia.
School of Earth and Planetary Science, Spatial Science Discipline, Curtin University, Perth, Australia.
Sci Total Environ. 2019 Jun 20;670:448-465. doi: 10.1016/j.scitotenv.2019.03.148. Epub 2019 Mar 14.
The Australian and African continents, regions prone to hydroclimate extremes (e.g., droughts and floods), but with sparse distribution of rain-gauge that are limited in time, rely heavily on complementary satellite and reanalysis data to provide important crucial information necessary for informing policies and management. The problem, however, is that satellite products suffer from systematic biases while reanalysis products carry over uncertainties from their forcing parameters. Multi-Source Weighted-Ensemble Precipitation (MSWEP) is a new global rainfall-product that merges satellite, rain-gauge and re-analysis data to exploit their advantages and minimise their disadvantages. Although MSWEP has been validated globally, this product, together with its potential applications, e.g., in water storage fluxes, river discharge and climate impacts studies over Australia and Africa, regions with urgent need of reliable products, has however, not been verified. Using GRACE satellite products, GLDAS model data, GRDC runoff products, and ENSO/IOD climate indices; five rainfall products - FLUXNET, BoM, GPCC, CHIRPS, and AgCFSR; and a suite of statistical methods (Pearson, Kolmogorov-Smirnov, PCA and Three-Corner-Hat (TCH)), this study (i) evaluates monthly MSWEP-V2.1 data (1981-2016), and (ii), assesses its potential applications to water storage flux (within the water balance framework), river discharge analysis, and climate impacts studies. The results show good MSWEP correlations and cumulative distribution with BoM product over most of Australia except in regions with heavy monsoonal rainfall, e.g., northern and north-western Australia where it tends to underestimate. Over Africa, MSWEP has no obvious advantages compared to insitu-GPCC, satellite-CHIRPS or reanalysis-AgCFSR. Furthermore, it is unable to reflect on major hydro-climate extremes over west, east and southern Africa, where it underestimates compared to CHIRPS. Its potential applications to water storage flux, discharge and climate impacts over the two continents show better suitability for water storage flux in Africa, while no advantages are seen compared to other rainfall products on other aspects.
澳大利亚和非洲大陆容易出现极端水文气候（如干旱和洪水），但雨量计分布稀疏且时间有限，严重依赖卫星和再分析数据的补充，以提供政策和管理所需的重要关键信息。然而，问题在于卫星产品存在系统偏差，而再分析产品则继承了其强迫参数带来的不确定性。多源加权集合降水（MSWEP）是一种新的全球降雨产品，它融合了卫星、雨量计和再分析数据，以发挥其优势并尽量减少其劣势。尽管MSWEP已在全球范围内得到验证，但该产品及其潜在应用，例如在澳大利亚和非洲的蓄水通量、河流流量和气候影响研究中，这些地区迫切需要可靠的产品，然而尚未得到验证。本研究使用GRACE卫星产品、GLDAS模型数据、GRDC径流产品和ENSO/IOD气候指数；五种降雨产品——FLUXNET、BoM、GPCC、CHIRPS和AgCFSR；以及一套统计方法（皮尔逊、柯尔莫哥洛夫-斯米尔诺夫检验、主成分分析和三角帽法（TCH）），（i）评估了1981 - 2016年月度MSWEP-V2.1数据，（ii）评估了其在蓄水通量（在水平衡框架内）、河流流量分析和气候影响研究中的潜在应用。结果表明，除了在季风降雨量大的地区，如澳大利亚北部和西北部，MSWEP与BoM产品在澳大利亚大部分地区具有良好的相关性和累积分布，但在这些地区MSWEP往往低估降雨量。在非洲，与现场观测的GPCC、卫星观测的CHIRPS或再分析的AgCFSR相比，MSWEP没有明显优势。此外，它无法反映非洲西部、东部和南部的主要水文气候极端情况，与CHIRPS相比，它在这些地区低估了降雨量。其在两大洲的蓄水通量、流量和气候影响方面的潜在应用表明，它在非洲的蓄水通量方面适用性更好，而在其他方面与其他降雨产品相比没有优势。
