Root Mean Square Difference between the nine ensemble member change anomalies of the seasonal mean near-surface (2m) temperature for the 10% percentile for 2066 - 2095 relative to 1976-2005, for the JJA season, under the RCP 8.5 pathway

Root Mean Square Difference for seasonal (JJA) mean near-surface (2m) temperature (°C) change from the 10% 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 temperature 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.

本数据集为南非地区在RCP 8.5典型浓度路径（Representative Concentration Pathway, RCP）下，相对于基准期（1976-2005年），2036-2065年季节（JJA，即6、7、8月）平均近地面（2米）气温（单位：℃）预估变化的10%分位数对应的均方根差（Root Mean Square Difference, RMSD）。为生成该图像，研究团队利用罗斯比中心区域模式（Rossby Centre regional model, RCA4），通过强迫其侧边界条件，将9个粗分辨率全球环流模式（General Circulation Models, GCM）降尺度至0.44°×0.44°的更高空间分辨率。该模式模拟的逐日气温平均值被用于生成季节尺度气温变化的预估结果。本次预估采用高排放情景RCP8.5，该情景预计到2100年大气二氧化碳浓度将达到约950ppm。本次计算得到的均方根差（RMSD）可展示模式模拟预估残差的不确定性范围，并能相对直观地呈现出预估不确定性高低各异的空间区域分布。