|Institution:||University of Victoria|
|Keywords:||coastal; surge; Alaska; Red Dog; synoptic; flooding; EOF|
|Full text PDF:||http://hdl.handle.net/1828/6020|
The southern Chukchi and Bering Sea region regularly experiences powerful storms that bring high winds that cause positive and negative water level set-up (storm surges) events. Positive set-up events can cause coastal inundation, sometimes extending far inland for low-relief locations, and negative set-up events can be problematic for shallow-draft marine equipment, such as barges. A ten year record (2004-2014) of water level data is available from a NOAA tide gauging station situated at the Teck Alaska Inc. Red Dog Mine Port Facility located to the north of the Bering Strait on the southwest Chukchi Sea coast. In this thesis these data are used to develop a database of water level set-up (storm surge) events using a novel identification methodology; by adapting fundamental wind storm identification concepts used by Atkinson (2005) and applying them to a water level dataset. The surge event database is then analyzed to identify primary types of events, to derive seasonal patterns and frequencies of occurrence, and to determine likely atmospheric driving mechanisms. There were 44 surge events identified – 21 positive, 23 negative – that tended to occur during the months of November, December, and January; none were recorded in the months May through August. The event typing work suggested four distinct surge patterns. Analysis of weather drivers, performed through visual interpretation of the temporal shape/form of the events and via use of an Empirical Orthogonal Function (EOF) analysis, suggested favoured locations for storm systems – the far eastern Chukotka Peninsula for positive set up events (west of Red Dog Dock), and the Alaska Peninsula for negative set ups (south of Red Dog Dock). A storm system situated to the west of the port generates southwest winds that drive positive set-up events, and a storm situated to the south generates easterly winds that drive negative set-up events. The sea level pressure weather patterns for positive set-up surge events are much stronger and shorter lived than for negative set-up events. This work has established an improved understanding of seasonal storm surge for the region and offers a potential basis for the improved forecasting of both positive and negative set-up surge events in the future.