Root Mean Square Difference between the nine ensemble member change anomalies of the annual mean near-surface (2m) temperature for the 10% percentile for 2036 - 2065 relative to 1976-2005, under the RCP 4.5 pathway

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

本数据集为南部非洲区域在典型浓度路径4.5（RCP 4.5）情景下，相对于当前基准时段（1976-2005年），2036-2065年预估的10%百分位所对应的年平均近地面（2米）气温（°C）变化的均方根差（Root Mean Square Difference, RMSD）。
为生成该可视化图像，研究借助罗斯比中心区域模式（Rossby Centre regional model, RCA4）对9个粗分辨率全球环流模式（General Circulation Models, GCM）进行降尺度处理，将其空间分辨率提升至0.44°×0.44°，并以该区域模式为基准提供侧边界强迫。该模式模拟的日平均气温数据被用于生成年变化预估结果。
本次预估采用中低（RCP4.5）情景，该情景预计到2100年时大气二氧化碳浓度约达560ppm。本次计算得到的对应均方根差可展示预估模式模拟残差的不确定性范围，并能相对呈现不同空间区域预估不确定性的高低分布格局。