Annual total rainfall percentage(%) change from the median, projected for 2066 - 2095 relative to the present (1975 - 2005), under the RCP 8.5 pathway.

Annual total rainfall percentage(%) change from the median, projected for 2066 - 2095 relative to the present (1975 - 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 thehigh (RCP8.5) pathway which associates CO2 concentrations of approximately 900ppm 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（RCP 8.5）情景下，2066—2095年相较于基准期（1975—2005年）的年总降雨量较中位数的百分比变化。本图像的生成流程为：选取9个粗分辨率全球环流模式（General Circulation Models, GCM），通过罗斯比中心区域模式（RCA4）对其侧边界进行强迫，将其降尺度至0.44°×0.44°的更高空间分辨率。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。本次预估基于高排放情景（RCP 8.5）生成，该情景预计到2100年大气二氧化碳浓度将达到约900ppm。本次计算得到的均方根误差（Root Mean Square Deviation, RMSD）可展示模式模拟残差预估结果的不确定性范围，并可相对呈现预估不确定性高低的空间分布区域。