Annual total rainfall (mm per year) change from the 10% percentile, projected for 2036 - 2065 relative to the present (1976-2005) under the of the RCP 4.5 pathway conditions.

Annual total rainfall (mm per year) change from the 10% percentile projected for 2036-2065, relative to present (1976 - 2005), under the RCP 4.5 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 medium to low (RCP4.5) pathway which associates CO2 concentrations of approximately 560ppm 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.

针对南部非洲区域，在典型浓度路径4.5（RCP 4.5）情景下，2036-2065年预估的年总降雨量（单位：毫米/年）相较于基准期（1976-2005年）的10%分位数的变化量。为生成该数据集的可视化成果，研究团队采用罗斯比中心区域模式（RCA4），将9个粗分辨率大气环流模式（General Circulation Models, GCM）的数据降尺度至0.44°×0.44°的精细空间分辨率，该模式以自身输出作为侧边界强迫场。该模式模拟的日降雨量平均值被用于生成年降雨量变化的预估结果。本次预估基于中低排放典型浓度路径4.5（RCP 4.5）情景，该情景预计到2100年大气二氧化碳浓度将达到约560ppm。本次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估结果的不确定性范围，并能相对展示出预估不确定性高低各异的空间区域分布特征。