Impact of Barrier Layer Thickness on SST in the Central Tropical North Atlantic
Impact of Barrier Layer Thickness on SST in the Central Tropical North Atlantic
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DOI：
10.1175/2008jcli2308.1
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发表时间：
2009-01
影响因子：
4.9
通讯作者：
G. Foltz;M. Mcphaden
中科院分区：
文献类型：
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作者：
G. Foltz;M. Mcphaden
利用三个长期系泊浮标的测量数据，研究了屏障层厚度（BLT）对热带北大西洋中部海表温度（SST）季节周期的影响。研究发现，BLT的季节变化通过对混合层底部垂直热通量的调制对海表温度产生了相当大的影响，其估计为混合层热平衡中的残余。当阻挡层较薄且混合层底部的垂直温度梯度较强时，与此相关的冷却效果最强。相反，厚屏障层与混合层底部垂直温度梯度的显著降低有关，这抑制了较冷的水向上转移到混合层。强迫海洋和耦合海洋-大气模式如果不能正确模拟屏障层，可能难以再现观测到的热带北大西洋海温的季节循环。
Measurements from three long-term moored buoys are used to investigate the impact of barrier layer thickness (BLT) on the seasonal cycle of sea surface temperature (SST) in the central tropical North Atlantic Ocean. It is found that seasonal variations of the BLT exert a considerable influence on SST through their modulation of the vertical heatflux at the base of the mixed layer, estimated as the residual in the mixed layer heat balance. Cooling associated with this term is strongest when the barrier layer is thin and the vertical temperature gradient at the base of the mixed layer is strong. Conversely, thick barrier layers are associated with a significant reduction in the vertical temperature gradient at the base of the mixed layer, which suppresses the upward transfer of cooler water into the mixed layer. Forced ocean and coupled ocean‐ atmosphere models that do not properly simulate the barrier layer may have difficulty reproducing the observed seasonal cycle of SST in the tropical North Atlantic.