Root Mean Square Difference between the nine ensemble member change anomalies of the seasonal mean near-surface (2m) temperature for the median for 2036 - 2065 relative to 1976-2005, for the JJA season, under the RCP 4.5 pathway

Root Mean Square Difference for seasonal (JJA) mean near-surface (2m) temperature (°C) change from the median projected for 2036-2065, relative to present (1976 - 2005), under the RCP 4.5 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 medium to low (RCP4.5) pathway which associates CO2 concentrations of approximately 560ppm 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.

本数据集表征南部非洲区域在典型浓度路径4.5（RCP 4.5）情景下，相较于基准时段（1976-2005年），2036-2065年季节（JJA，即6、7、8月）平均近地表（2米高度）气温（℃）变化的预估中值的均方根差（Root Mean Square Difference）。
为生成该数据集配套的可视化图像，研究采用罗斯比中心区域模式（RCA4）为侧边界提供强迫场，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。
该模式模拟的日平均气温数据被用于生成季节气温变化的气候预估结果。
本次预估基于中低强度的RCP 4.5排放情景，该情景预计到2100年大气二氧化碳浓度约为560ppm。
由此计算得到的均方根差（RMSD, Root Mean Square Difference）可展示模式模拟预估残差的不确定性范围，并直观反映空间区域内预估不确定性的高低分布特征。