Synoptic forcing of wave states in the southeast Chukchi Sea, Alaska, at an offshore location

A bottom-mounted Recording Doppler Current Profiler was placed at an offshore location (depth of 34 m) in the southeast Chukchi Sea, Alaska, from July through December 2007 (UTC) with the objective of linking observed wave activity—wind-sea and swells—to their synoptic drivers. A total of 47 intervals of elevated wave state were recorded: 29 exceeding 1 m significant wave height (SWH), 16 exceeding 2 m SWH, and 3 m exceeded on two occasions; during one of those, a SWH of 4 m was observed. Detailed analysis of the two large events, including comparison with high-resolution reanalysis wind data (North America Regional Reanalysis), showed wave direction from the east, varied about 15° to the north (counterclockwise) from the wind direction, and current flow in the opposite direction (from the west). This is thought to be the influence of a strong “wind-sea” presence. Regarding classic wave limitations, although the SE Chukchi Sea is a large embayment bordered by land to the east, fetch limitations from the northeast and southeast did not appear to be a constraint for the wind speeds indicated by reanalysis. These two events appeared to be driven by winds associated with cyclonic systems that moved into the eastern Bering Sea and stalled. Examination of smaller waves associated with these events suggested that waves of 1.5 m SWH or less are likely part of another regime and can either be swell or wind-sea, moving in from the open Chukchi Sea to the northwest or through the Bering Strait to the south. Copyright The Author(s) 2012