Representation of Southern Ocean Properties across Coupled Model Intercomparison Project Generations: CMIP3 to CMIP6
Representation of Southern Ocean Properties across Coupled Model Intercomparison Project Generations: CMIP3 to CMIP6
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DOI：
10.1175/jcli-d-19-0970.1
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发表时间：
2020-08-01
影响因子：
4.9
通讯作者：
Pandde, Amarjiit
中科院分区：
文献类型：
--
作者：
Beadling, R. L.;Russell, J. L.;Pandde, Amarjiit
南大洋海气热交换和碳交换对气候状态起着重要的调节作用。SO在储存人类活动产生的热量和碳方面所起的主导作用是那里存在的独特而复杂的海洋环流的直接结果。前几代的气候模式一直在努力准确地表示影响大尺度海洋环流的关键SO属性和过程。这导致前几代模型对二十一世纪SO状态的预测信心较低。这项分析提供了一个详细的评估模型的能力，有助于第六阶段的耦合模型相互比较项目（CMIP 6）代表重要的观测为基础的SO属性。此外，还介绍了CMIP 6相对于CMIP 3和CMIP 5的性能的全面概述。CMIP 6模型在表面风应力强迫方面表现出更好的性能，模拟了更强和更少的赤道偏置风场，转化为德雷克通道纬度上Ekman上升流的改进表示。越来越多的模型模拟南极绕极流（ACC）运输的观测不确定性相对于前几代，但是，几个模型表现出非常弱的运输。一般来说，上层SO相对于观测结果仍然偏暖和新鲜，南极海冰的范围仍然很差。虽然在许多指标中发现了代际改进，但强调了持续的系统性偏差，这应该是模型开发期间的优先事项。在解释该区域的预测趋势或地球化学性质时，需要考虑这些偏差。
The air-sea exchange of heat and carbon in the Southern Ocean (SO) plays an important role in mediating the climate state. The dominant role the SO plays in storing anthropogenic heat and carbon is a direct consequence of the unique and complex ocean circulation that exists there. Previous generations of climate models have struggled to accurately represent key SO properties and processes that influence the large-scale ocean circulation. This has resulted in low confidence ascribed to twenty-first-century projections of the state of the SO from previous generations of models. This analysis provides a detailed assessment of the ability of models contributed to the sixth phase of the Coupled Model Intercomparison Project (CMIP6) to represent important observationally based SO properties. Additionally, a comprehensive overview of CMIP6 performance relative to CMIP3 and CMIP5 is presented. CMIP6 models show improved performance in the surface wind stress forcing, simulating stronger and less equatorward-biased wind fields, translating into an improved representation of the Ekman upwelling over the Drake Passage latitudes. An increased number of models simulate an Antarctic Circumpolar Current (ACC) transport within observational uncertainty relative to previous generations; however, several models exhibit extremely weak transports. Generally, the upper SO remains biased warm and fresh relative to observations, and Antarctic sea ice extent remains poorly represented. While generational improvement is found in many metrics, persistent systematic biases are highlighted that should be a priority during model development. These biases need to be considered when interpreting projected trends or biogeochemical properties in this region.