Annual total rainfall (mm per year) change from the 90% percentile, projected for 2036 - 2065 relative to the present (1976-2005) under the of the RCP 8.5 pathway conditions.

Annual total rainfall (mm per year) change from the 90% percentile projected for 2036-2065, relative to present (1976 - 2005), under the RCP 8.5 pathway for the southern African region. To generate the image, nine coarse General Circulation Models (GCM) are downscaled to a finer spatial resolution (0.44°x 0.44°) using the Rossby Centre regional model (RCA4) forcing its lateral boundaries. The model simulated daily rainfall averages, which are used to generate projections of annual change. The projections are generated using the high (RCP8.5) pathway which associates CO2 concentrations of approximately 950ppm by the year 2100. The associated RMSD it calculated and shows the uncertainty range of the projected model simulated residual values, and gives a relative perspective of spatial areas associated with higher and lower projection uncertainties.

本数据集表征南部非洲区域在典型浓度路径8.5（Representative Concentration Pathway 8.5，RCP8.5）情景下，2036-2065年的年总降雨量（单位：毫米/年）相较于基准期（1976-2005年）90%分位数预测值的变化量。为生成该图像，本研究采用罗斯比中心区域气候模式（RCA4）对9个粗分辨率大气环流模式（General Circulation Models, GCM）进行降尺度处理，将其空间分辨率提升至0.44°×0.44°，并以该模式作为侧边界强迫场。该模式模拟的日降雨量平均值被用于计算年降雨量变化的预测结果。本次预测基于高排放情景RCP8.5开展，该情景下至2100年大气二氧化碳浓度将达到约950ppm。研究同时计算了对应的均方根误差（Root Mean Square Deviation, RMSD），该指标可表征模式模拟残差预测值的不确定性范围，并能相对展示出预测不确定性高低各异的空间区域分布特征。