Root Mean Square Difference between the nine ensemble member change anomalies of the seasonal mean near-surface (2m) temperature for the 90% percentile for 2066 - 2095 relative to 1976-2005, for the DJF season, under the RCP 8.5 pathway

Root Mean Square Difference for seasonal (DJF) mean near-surface (2m) temperature (°C) 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 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.

本数据集表征南部非洲区域在典型浓度路径8.5（RCP 8.5）情景下，相较于基准期（1976-2005年），2066-2095年冬季（12月、1月、2月，DJF）近地表（2米）气温季节平均预估变化相对于90%百分位的均方根差（Root Mean Square Difference, RMSD）。为生成该数据集对应的可视化图像，研究采用罗斯比中心区域模式（RCA4）对9个粗分辨率大气环流模式（GCM）进行降尺度处理，将其空间分辨率提升至0.44°×0.44°，并以该模式作为侧边界强迫场。该模式模拟得到逐日气温平均值，以此生成季节气温变化的预估结果。本次预估基于高排放情景（RCP8.5），该情景预计到2100年二氧化碳浓度将达到约950ppm。本次计算得到的均方根差可反映模式模拟预估残差的不确定性范围，能够直观展现不同空间区域预估不确定性的高低差异。