Date of Award

Spring 1-1-2014

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Atmospheric & Oceanic Sciences

First Advisor

John J. Cassano

Second Advisor

Julie K. Lundquist

Third Advisor

James A. Maslanik

Fourth Advisor

Andrew J. Monaghan

Fifth Advisor

Nicole S. Lovenduski

Abstract

In September 2009, several unmanned aerial vehicles (UAV) flew over Terra Nova Bay (TNB), Antarctica to collect measurements of the three dimensional properties of the atmospheric boundary layer. TNB has important implications on the atmosphere, ocean, and cryosphere due to an open water polynya in the region. Within the area of lower sea ice concentrations, significant air-sea interactions occur. Until September 2009, observations of the wintertime atmospheric boundary layer over the polynya had not been collected. The UAVs captured important information on the structure, moistening, and warming of the atmosphere due to the presence of the polynya.

This study seeks to increase our understanding of the air-sea interactions in TNB by estimating and assessing the primary forcing mechanisms of heat exchange in the region. Three flights in September 2009 collected measurements designed to capture the evolution of the atmospheric boundary layer as the continental air passed over the relatively warmer and moister surface of the polynya. This dissertation first analyzes climatological observations to put the field season observations into a broader context, showing September 2009 was an anomalous year. Next, a new and innovative methodology, based only on atmospheric data, estimates heat fluxes over TNB. Finally, UAV and satellite data are synthesized to identify the primary forcing mechanisms controlling the fluxes in TNB. The structure of the atmospheric boundary layer is also studied as the continental air mass moves over the polynya.

This work is significant for several reasons. First, the UAV data collected are the first in-situ observations gathered during the wintertime months over the polynya. This information is key for understanding the significant air-sea interactions that occur during this season. Second, the methodology developed to estimate heat exchange from the in situ UAV data provides a unique approach for quantifying air-sea interactions without bulk flux algorithms that have large uncertainty. Finally, a better understanding of the forcing mechanisms of energy exchange in this region has widespread applicability toward other polynyas in the Arctic and Antarctic, and in areas of cold air outbreaks. This work also has potential to improve the uncertainty of bulk flux algorithms in model output.

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Meteorology Commons

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