第七届青年地学论坛

Data from a mooring array on the eastern shelfbreak/upper-slope of the Chukchi Sea from fall 2013 to fall 2014 and two moorings in the west (at 166°W) from summer 2002 to fall 2004 are used to describe and quantify the circulation of the region. The timeseries from northeastern mooring array revealed the year-round existence of the eastward-flowing shelfbreak jet and, seaward of this, the westward-flowing Chukchi Slope Current. In the mean the slope current is estimated to transport 0.57 ± 0.04 Sv of Pacific water, while the bottom-intensified shelfbreak jet transports 0.009 ± 0.003 Sv towards Barrow Canyon. The slope current is surface-intensified in summer and fall, and in winter and spring it becomes middepth-intensified, moves shoreward, and weakens. Two extreme states of the circulation were identified: (1) an enhanced slope current and reversed (westward flowing) shelfbreak jet; and (2) a strong eastward-flowing shelfbreak jet and weak slope current. The former state occurs when the wind stress curl on the Chukchi shelf is positive, and the latter state occurs when the curl is negative. A simple theoretical model is used to determine the changes in sea surface height due to such wind stress curl forcing, which is consistent with the observed changes in flow seaward of the shelf – both in amplitude and phase – via geostrophic set up. In the west, the mean velocity at the inshore mooring is eastward and bottom intensified, which is regarded as the signature of Chukchi shelfbreak jet. At the offshore site the mean flow is westward and surface-intensified over the two-year period, which is regarded as at the location between the shelfbreak jet and outer slope current, resulting in the flow here affected by both currents. 

circulation; Chukchi Sea; slope current; shelfbreak jet