Locally enhanced wintertime air-sea interaction and deep oceanic mixed layer formation associated with the subarctic front in the North Pacific

Abstract

[1] Satellite-derived high-resolution air-sea flux data and Argo float data were analyzed to reveal the fine-scale spatial structures of air-sea turbulent heat and momentum fluxes and their relationship with the deep oceanic mixed layer around the subarctic front (SAF) in the North Pacific. An important feature inferred from the satellite-derived dataset is the presence of a pair of positive and negative air-sea flux anomaly bands with a width of 100–200 km on both sides of the SAF. Such a fine-scale structure in air-sea fluxes has not been captured in previous datasets. The SAF plays a significant role in determining the fine-scale structure of air-sea fluxes. The oceanic mixed layer is deeper to the south of the SAF, and the maximum mixed layer depth is observed near the positive anomaly band in air-sea fluxes. This study concludes that active air-sea interactions due to the presence of the SAF enhances upward air-sea heat and momentum fluxes to the south of SAF and selectively produces a deep oceanic mixed layer where the formation of Transition Region Mode Water occurs.