Seasonal total rainfall (mm per 3-month season) change from the 90% percentile projected for 2066-2095, relative to present (1976 - 2005), for DJF season under the RCP 8.5 pathway

Seasonal (DJF) rainfall (mm per month) change from the 90% percentile 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 seasonal 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.

本数据集聚焦南非区域，展示了在典型浓度路径8.5（RCP 8.5）排放情景下，2066-2095年季节降水（DJF，即12月至次年2月）的逐月降雨量（单位：毫米/月）相对于1976-2005年当前基准期的预估变化量，该变化以90%百分位为参照基准。
为生成该可视化图像，研究团队利用罗斯比中心区域气候模式（Rossby Centre regional model, RCA4），将9套粗分辨率全球环流模式（General Circulation Models, GCM）的模拟结果降尺度至0.44°×0.44°的更高空间分辨率，并以RCA4模式作为侧边界强迫场。
该模式的逐日降雨量模拟平均值被用于生成季节降水变化的预估结果。
本次预估基于高排放情景（RCP 8.5）路径开展，该情景预计到2100年大气二氧化碳浓度将达到约950ppm。
研究中计算了对应的均方根偏差（Root Mean Square Deviation, RMSD），其结果可用于展示预估模型模拟残差的不确定性范围，并从相对视角区分预估不确定性较高与较低的空间区域。