Seasonal mean near-surface (2m) temperature (°C) change from the 90% percentile projected for 2066 - 2095, relative to present (1976 - 2005), for MAM season under the RCP 4.5 pathway

Seasonal (MAM) mean near-surface (2m) temperature (°C) change from the 90% percentile projected for 2066-2095, 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.

针对南部非洲区域，在典型浓度路径4.5（RCP 4.5）情景下，相对于基准时段（1976-2005年），2066-2095年季节（MAM，即三月、四月、五月）平均近地面（2米高度）气温（℃）的变化量为该时段预测值的90%分位相对基准期的差值。为生成该数据集对应的可视化图像，研究人员采用罗斯比中心区域模式（RCA4），通过为其施加侧边界强迫条件，将9套粗分辨率全球环流模式（GCM）的结果降尺度至0.44°×0.44°的更高空间分辨率。该区域模式模拟得到的日平均气温数据，被用于生成季节尺度气温变化的预测结果。本次预测基于中低排放情景（RCP4.5）构建，该情景预计到2100年大气二氧化碳浓度将达到约560ppm。研究同时计算了对应的均方根偏差（RMSD），该指标可表征模式模拟残差预测值的不确定性范围，并能直观展现不同空间区域的预测不确定性高低分布特征。