Title: Contributions of the Bering Strait Throughflow to Oceanic Meridional Heat Transport under Modern and Last Glacial Maximum Climate Conditions

Journal: Journal of Oceanology and Limnology,37 (2): 398-409

Authors: ZHANG C. -J., and X. -P. Lin*

Abstract: Paleo reconstructions and model simulations have suggested the Bering Strait plays a pivotal role in climate change. However, the contribution of the Bering Strait throughfl ow to oceanic meridional heat transport (OMHT) is about 100 times smaller than the OMHT at low latitudes in the modern climate and it is generally ignored. Based on model simulations under modern and Last Glacial Maximum (LGM, ~21 ka; ka=thousand years ago) climate conditions, this study highlights the importance of the Bering Strait throughfl ow to OMHT. The interbasin OMHT induced by the Bering Strait throughfl ow is estimated by interbasin-intrabasin decomposition. Similar to barotropic-baroclinic-horizontal decomposition, we assume the nonzero net mass transport induced by interbasin throughfl ows is uniform across the entire section, and the interbasin term is separated to force zero net mass transport for the intrabasin term. Based on interbasinintrabasin decomposition, the contribution of the Bering Strait throughfl ow is determined as ~0.02 PW (1 PW=10¹⁵ W) under the modern climate, and zero under the LGM climate because the closed Bering Strait blocked interbasin throughfl ows. The contribution of the Bering Strait throughfl ow to OMHT is rather small, consistent with previous studies. However, comparisons of OMHT under modern and LGM climate conditions indicate the mean absolute changes are typically 0.05 and 0.20 PW in the North Atlantic and North Pacifi c, respectively. Thus, the contribution of the Bering Strait throughfl ow should not be ignored when comparing OMHT under diff erent climate conditions.