Date of Award

2013

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Environmental Science

First Advisor

Zhang, Jing

Abstract

The Weather Research and Forecasting model and its variational Data Assimilation system WRFDA has been applied to the Arctic marginal ice zone along the Chukchi-Beaufort Seas for High-resolution Atmospheric Reanalysis (CBHAR) study. To ensure the best reanalysis quality, WRFDA is optimized for the study area through a set of assimilation sensitivity experiments. The sensitivity of WRFDA to model background errors (BE), and the assimilation of various observational datasets, including both in situ observations and satellite retrievals is examined. It's found that a customized BE is necessary in order to achieve positive impacts with WRFDA. A careful selection of data to be assimilated is also essential. To improve our understanding of temporal and spatial structures of the area's surface wind, an important parameter linking dynamical processes among different components of the environmental system, the newly developed CBHAR reanalysis is used to analyze the area's mesoscale wind climatology for the data period of 1979 to 2009. In the study area, sea breezes, up/downslope winds, and mountain barrier effects are clearly captured by CHBAR. Upslope winds occur from March to September. Sea breeze begins in May, reaches its maximum in July. Mountain barrier effects are profound along the Chukotka Mountains and in the Chukchi Sea during cold seasons. The impacts of synoptic weather patterns including Arctic storm and Beaufort High on the area's mesoscale circulations are analyzed. Strong storm activity reduces the strength of sea breeze and eastward location of Beaufort High weakens the mountain barrier effect in the Chukchi Sea.

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