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

Seasonal (SON) 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.

本数据集表征南非区域在典型浓度路径8.5（Representative Concentration Pathway 8.5，简称RCP 8.5）情景下，相较于基准期（1976-2005年），2036-2065年季节平均（SON，即9月、10月、11月）近地面2米气温（摄氏度）预估结果的90%分位数对应的变化量。为生成该可视化成果，研究采用罗斯比中心区域气候模式（Rossby Centre Regional Climate 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计算季节尺度气温变化的预估结果。本次预估采用的高排放情景（RCP8.5）预计到2100年时，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），其可表征模式模拟残差预估结果的不确定性范围，并能直观反映不同空间区域预估不确定性的高低分布特征。