Root Mean Square Difference between the nine ensemble member change anomalies of the annual total rainfall for the median for 2066 - 2095 relative to 1976-2005, under the RCP 8.5 pathway

Root Mean Square Difference for annual total rainfall (mm per year) change from the median projected for 2066-2095, 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.

本数据集为南部非洲区域在典型浓度路径8.5（Representative Concentration Pathway 8.5，RCP8.5）下，以当前基准时段（1976-2005年）为参照，2066-2095年预测中值对应的年总降水量（毫米/年）变化的均方根差（Root Mean Square Difference，RMSD）。为生成该图像，我们使用罗斯比中心区域模式（Rossby Centre Regional Model，RCA4）为其侧边界提供强迫场，将9个粗分辨率大气环流模式（General Circulation Models，GCM）降尺度至0.44°×0.44°的更高空间分辨率。该模式模拟的日降水量平均值被用于生成年变化的预测结果。本次预测基于高排放情景（RCP8.5），该情景预计到2100年二氧化碳浓度将达到约950ppm。本次计算得到的相关均方根差可展示模式模拟预测残差的不确定性范围，并能相对直观地呈现出预测不确定性高低各异的空间区域分布特征。