Root Mean Square Difference between the nine ensemble member change anomalies of the seasonal total rainfall for the 90% percentile for 2036 - 2065 relative to 1976-2005, for the JJA season, under the RCP 8.5 pathway

Root Mean Square Difference for seasonal (JJA) rainfall (mm per month) change from the 90% percentile projected for 2036-2065, 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.

本数据集聚焦南部非洲地区，计算了典型浓度路径8.5（Representative Concentration Pathway 8.5，RCP8.5）下，2036-2065年季节（JJA，即6、7、8月）降雨量（单位：毫米/月）的90%分位数预测值相较于基准期（1976-2005年）的变化的均方根差（Root Mean Square Difference，RMSD）。
为生成该可视化图像，研究通过罗斯比中心区域模式（Rossby Centre regional model, RCA4）强迫侧边界条件，将9套粗分辨率全球环流模式（General Circulation Models, GCM）降尺度至0.44°×0.44°的精细空间分辨率。该模式模拟的日降雨量平均值被用于生成季节降雨变化的预测结果。
本次预测采用RCP8.5高排放情景，该情景预计至2100年大气二氧化碳浓度将达到约950ppm。
本次计算得到的对应均方根差，可展示模式模拟预测残差的不确定性范围，并直观呈现空间区域内预测不确定性的高低分布特征。