Developing novel storminess metrics and evaluating seasonal predictability of storminess indicators in the north Pacific and Alaskan regions

• Main Author: Shippee, Norman
• Other Authors: Atkinson, David
• Format: Thesis
• Language: English
• Published: 2016
• Subjects: Climate; Extratropical Cyclones; Storminess; Wind Events; North Pacific; Alaska; Arctic; Pacific
• Online Access: http://hdl.handle.net/1828/7519

Extratropical cyclones (ETCs) are a common feature of mid- and high-latitudes which, on a large scale, are a primary mechanism by which heat and moisture are transported from equator to pole. ETCs also exert a major impact at smaller scales. Communities along the western coast of Alaska face many types of impacts generated by the winds associated with ETCs, including storm surges, sea water intrusion into fresh water stores, and coastal erosion. Such “strong wind events”, which can occur independent of an ETC, can also generate hazardous sea states and associated impacts on shipping. With no roads, coastal Alaska relies heavily on marine and air transportation. Hazards posed to marine and air travel are often related to two main types of weather: wind and fog. Consultations with stakeholders in the marine transportation community have indicated more precisely specific aspects of poor weather, such as high wind events, that are problematic, including the idea that the periods between strong wind events, defined as lull periods, represent an important metric when planning travel between points of safe harbour. Three separate studies of storminess metrics in the North Pacific and Alaskan regions are presented. The first study presents both a comparison of two storm identification and tracking algorithms and an evaluation of the general characteristics of extratropical cyclones for the North Pacific as portrayed in two reanalyses. The second study applies a modified wind event identification algorithm to reanalysis data to evaluate the spatial climatological patterns of wind events in the circum-Arctic. The third study tests the statistical relationships and predictability of two measures of storm activity - cyclone track density (TDEN) and wind event frequency - in the North Pacific using teleconnection indices exhibiting local influence. The first study showed that the general patterns and trends of cyclone characteristics are similar between the two methods, though with increased values of cyclogenesis density, ...