This study compared the historical simulations and future projections of precipitation and temperature of Coupled Model Intercomparison Project (CMIP)5 and CMIP6 general circulation models (GCMs) to quantify the differences in the projections due to differences in scenarios. Five performance indicators were used to quantify the model reproducibility of the observed precipitation levels at 22 stations for the historical period of 1970–2005. The percentages of change in precipitation and temperature were estimated for the near (2025–2060) and far future (2065–2100) for two Representative Concentration Pathway (RCP)4.5 and RCP8.5 scenarios of CMIP5 and two Shared Socioeconomic Pathway (SSP)2–4.5 and SSP5-8.5 scenarios of CMIP6. The uncertainty in the projection in each case was calculated using the reliability ensemble average (REA) method. As a result, the CMIP6 GCMs showed an improvement compared with the CMIP5 GCMs with regard to the ability to simulate the historical climate. The uncertainty in the precipitation projections was higher for SSPs than that in RCPs. With regard to the temperature, the uncertainty was higher for RCPs than for SSPs. The ensemble means of the precipitation and temperature showed higher changes in the far future compared with the near future for both RCPs and SSPs. This study contributes to improvement in the confidence of future projections using CMIP6 GCMs and bolsters our understanding of the relative uncertainty in SSPs and RCPs.

中文翻译：

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CMIP6 和 CMIP5 大气环流模型对韩国降水和气温预测的时空差异和不确定性

本研究比较了耦合模式比对项目 (CMIP)5 和 CMIP6 大环流模式 (GCM) 的降水和温度的历史模拟和未来预测，以量化由于情景差异导致的预测差异。五个性能指标用于量化 1970-2005 年历史时期 22 个站点观测到的降水水平的模型再现性。针对 CMIP5 的两个代表性浓度路径 (RCP)4.5 和 RCP8.5 情景以及两个共享社会经济路径 (SSP)，估计了近期 (2025-2060) 和远未来 (2065-2100) 降水和温度变化的百分比CMIP6 的 2-4.5 和 SSP5-8.5 场景。每种情况下投影的不确定性是使用可靠性集合平均 (REA) 方法计算的。因此，与 CMIP5 GCM 相比，CMIP6 GCM 在模拟历史气候的能力方面表现出改进。SSP 的降水预测的不确定性高于 RCP。关于温度，RCP 的不确定性高于 SSP。与近期相比，RCP 和 SSP 的降水和温度的集合均值在远期表现出更高的变化。这项研究有助于提高使用 CMIP6 GCM 进行未来预测的信心，并增强我们对 SSP 和 RCP 中相对不确定性的理解。关于温度，RCP 的不确定性高于 SSP。与近期相比，RCP 和 SSP 的降水和温度的集合均值在远期表现出更高的变化。这项研究有助于提高使用 CMIP6 GCM 进行未来预测的信心，并增强我们对 SSP 和 RCP 中相对不确定性的理解。关于温度，RCP 的不确定性高于 SSP。与近期相比，RCP 和 SSP 的降水和温度的集合均值在远期表现出更高的变化。这项研究有助于提高使用 CMIP6 GCM 进行未来预测的信心，并增强我们对 SSP 和 RCP 中相对不确定性的理解。