Intermodel CMIP5 relationships in the baseline Southern Ocean climate system and with future projections
Intermodel CMIP5 relationships in the baseline Southern Ocean climate system and with future projections
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南大洋气候系统基线和未来预测的 CMIP5 模型间关系
DOI：
10.1002/essoar.10504633.1
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Kajtar J
中科院分区：
文献类型：
--
作者：
Kajtar J
气候模式对全球气候的模拟特性有很大的差异。在早期历史时期，为耦合模式相互比较项目（CMIP 5）第五阶段做出贡献的模式的绝对全球平均表面气温范围为~12-15 °C。其他气候参数与全球平均温度有关，例如海冰面积、大气环流模式，进而云量、降水量和反照率。基线气候状态的准确表示对于有意义的未来气候预测至关重要，因为基线条件可能决定变化的能力。例如，最初海冰面积较小的模型随着地球变暖而失去海冰的可能性较小。在CMIP 5模式中，发现在基线气候状态下，南大洋温度、短波辐射、云量、中纬度涡动急流位置和南极海冰面积之间存在相关性。基线温度关系延伸到同一组变量的预测未来变化。因此，南大洋表面温度最初较低的模型倾向于表现出更多的全球变暖，反之亦然，最初较暖的模型，可以与基线南大洋气候系统偏差。对CMIP 6新数据的初步研究显示，趋势向南极地区转移，这可能与南大洋偏差的减少有关，随着更多CMIP 6模型数据的可用，这促使对南极地区偏差的审查。
Climate models exhibit a broad range in the simulated properties of the global climate. In the early historical period, the absolute global mean surface air temperature of models contributing to the fifth phase of the Coupled Model Intercomparison Project (CMIP5) spans a range of ~12-15 °C. Other climate parameters are linked to the global mean temperature, such as sea ice area, atmospheric circulation patterns, and by extension cloudiness, precipitation and albedo. Accurate representation of the baseline climate state is crucial for meaningful future climate projections, since the baseline conditions may dictate the capacity for change. For example, a model with initially smaller sea ice area has less potential to lose sea ice as the planet warms. Amongst the CMIP5 models, it is found that in the baseline climate state there are coherences between Southern Ocean temperature, outgoing shortwave radiation, cloudiness, the position of the mid-latitude eddy-driven jet, and Antarctic sea ice area. The baseline temperature relationship extends to projected future changes in the same set of variables. The tendency for models with initially cooler Southern Ocean surface temperature to exhibit more global warming, and vice versa for initially warmer models, can therefore be linked to baseline Southern Ocean climate system biases. A first look at emerging data from CMIP6 reveals a shift of the tendency towards the Antarctic region, potentially linked to a reduction in biases over the Southern Ocean, which prompts an examination of biases in the Antarctic region as more CMIP6 model data becomes available.