Seasonal mean near-surface (2m) temperature (°C) change from the 90% percentile projected for 2036-2065, relative to present (1976 - 2005), for JJA season under the RCP 8.5 pathway

Seasonal (JJA) mean near-surface (2m) temperature (°C) 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 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.

针对南部非洲区域，在典型浓度路径8.5（Representative Concentration Pathway 8.5, RCP 8.5）情景下，相对于基准期（1976-2005年），2036-2065年预估的90%分位值对应的季节（JJA，即6-8月）近地表（2米高度）气温（单位：℃）变化量。本数据集可视化图像的生成流程如下：将9个粗分辨率全球环流模式（General Circulation Models, GCM）的模拟结果，通过罗斯比中心区域模式（Rossby Centre regional model, RCA4）进行降尺度处理，将空间分辨率提升至0.44°×0.44°，并以RCA4模式作为侧边界强迫场。该模式模拟的日平均气温数据，被用于生成季节尺度气温变化的预估结果。本次预估基于高排放情景（RCP8.5）开展，该情景预计至2100年大气二氧化碳浓度将达到约950ppm。研究同时计算了相关的均方根误差（Root Mean Square Deviation, RMSD），用以表征模式模拟残差预估结果的不确定性范围，并直观呈现预估不确定性高低不同的空间区域分布特征。