Insights into Decadal North Atlantic Sea Surface Temperature and Ocean Heat Content Variability from an Eddy-Permitting Coupled Climate Model
Insights into Decadal North Atlantic Sea Surface Temperature and Ocean Heat Content Variability from an Eddy-Permitting Coupled Climate Model
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DOI：
10.1175/jcli-d-18-0709.1
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发表时间：
2019-08
影响因子：
4.9
通讯作者：
B. Moat;B. Sinha;S. Josey;J. Robson;P. Ortega;F. Sévellec;N. P. Holliday;G. McCarthy;A. New;J. Hirschi
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文献类型：
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作者：
B. Moat;B. Sinha;S. Josey;J. Robson;P. Ortega;F. Sévellec;N. P. Holliday;G. McCarthy;A. New;J. Hirschi
海洋混合层热收支方法是用来调查的物理过程，确定副极地北大西洋（SPNA）的海表温度（SST）和海洋热含量（OHC）的变化在十年到几十年的时间尺度上使用的国家的最先进的气候模式HadGEM 3-GC 2。新元素包括发展方程的异常SST的演变为年际和更长的时间尺度的形式类似于OHC，参数化的扩散热通量在混合层的基础上，和分析的复合大西洋纬向翻转环流（AMOC）事件。从两个来源的OHC和SST变率的贡献进行了评估：1）净海洋-大气热通量和2）所有其他过程，包括平流，扩散，并夹带SST。OHC趋势的异常在SPNA周围的几十年时间尺度上的传播具有明显的关系，以AMOC的阶段。在SPNA东部和西部，AMOC异常导致SST趋势，SST趋势反过来导致OHC趋势。在SPNA的OHC和SST的变化在十年的时间尺度上占主导地位的AMOC的变化，因为它控制平流的变化，这被证明是占主导地位的条款在OHC预算。OHC和SST之间的滞后被追溯到OHC的平流项和SST的平流夹带项之间的差异。新的结果对解释CMIP 6气候模式评估中大西洋热量吸收的变化具有影响。
An ocean mixed layer heat budget methodology is used to investigate the physical processes determining subpolar North Atlantic (SPNA) sea surface temperature (SST) and ocean heat content (OHC) variability on decadal to multidecadal time scales using the state-of-the-art climate model HadGEM3-GC2. New elements include development of an equation for evolution of anomalous SST for interannual and longer time scales in a form analogous to that for OHC, parameterization of the diffusive heat flux at the base of the mixed layer, and analysis of a composite Atlantic meridional overturning circulation (AMOC) event. Contributions to OHC and SST variability from two sources are evaluated: 1) net ocean–atmosphere heat flux and 2) all other processes, including advection, diffusion, and entrainment for SST. Anomalies in OHC tendency propagate anticlockwise around the SPNA on multidecadal time scales with a clear relationship to the phase of the AMOC. AMOC anomalies lead SST tendencies, which in turn lead OHC tendencies in both the eastern and western SPNA. OHC and SST variations in the SPNA on decadal time scales are dominated by AMOC variability because it controls variability of advection, which is shown to be the dominant term in the OHC budget. Lags between OHC and SST are traced to differences between the advection term for OHC and the advection–entrainment term for SST. The new results have implications for interpretation of variations in Atlantic heat uptake in the CMIP6 climate model assessment.