Exploring integrated kinetic energy of polar mesoscale storms to estimate sea ice formation and salt fluxes in the Weddell Sea
Date
2015
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Publisher
University of Delaware
Abstract
This dissertation examines the relationship between polar cyclones and sea ice cover. Through this research, an archive of polar cyclones is created. The archive contains storms for the time period 01 January 1979 through 31 August 2014 for the Weddell Sea, a region east of the Antarctic Peninsula extending to where the Southern Ocean and Indian Ocean meet. The four defined properties of polar cyclones used in this work are: high wind speeds, low pressures, short duration, and small spatial scales. The storm strength is expressed specifically through the maximum wind speed and minimum sea level pressure. The archive additionally includes characteristics of individual storms including the storm date, duration, strength, and size which are analyzed and compared to changes in sea ice cover during each storm. Subsequently, this research quantifies linkages between polar cyclones and sea ice by computing each storm's integrated kinetic energy as a measure of the size, duration, and wind speeds. Specific linkages include the surface energy balance, sea ice growth rate, and the quantity of brine rejected to the top of the water column. The results show that the area of open water is the biggest contributor to sea ice growth and brine production through new ice formation. The ejected brine from the ice increases the density of sea water in the nearby upper ocean layers which contribute to the destabilization of the water column. Subsequently, the destabilization of the water column helps to form Weddell Sea Bottom Water - the coldest and densest water mass on the planet and major contributor to the global ocean circulation. Hence, the storm climatology developed herein provides a new quantitative resource for establishing significant links between polar storms and Weddell Sea deep water formation.