Annual total rainfall (mm per year) change from the 10% percentile, projected for 2066 - 2095 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 2066-2095, 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.南非地区在典型浓度路径4.5（Representative Concentration Pathway 4.5，RCP4.5）情景下，2066-2095年的预估年总降雨量（单位：毫米/年）相较于基准期（1976-2005年）10%分位数的变化量。为生成该可视化成果，本研究采用罗斯比中心区域模式（Rossby Centre regional model，RCA4）作为侧边界强迫场，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°。基于该模式模拟的日降雨量平均值，可推算得到年降雨量变化的预估结果。本次预估基于中等至低排放情景（RCP4.5），该情景预计到2100年大气二氧化碳浓度约为560ppm。研究同时计算了对应的均方根误差（Root Mean Square Deviation，RMSD），该指标可反映模式模拟残差预估结果的不确定性范围，并能相对展示不同空间区域预估不确定性的高低分布特征。