Date of Award

2013

Degree Type

Thesis

Degree Name

Master of Science in Oceanography

Department

Oceanography

First Advisor

John T. Merrill

Abstract

A comprehensive analysis of regional near-surface wind speed characteristics is presented based on data from 9 coastal sites, extending over periods of 20 to 39 years, with a mean duration of 33 years. Six terrestrial data sets were obtained from the National Climatic Data Center (NCDC), and 3 additional buoy data sets came from the National Data Buoy Center (NDBC). Data sets contain either sub-hourly or hourly wind speed averages from near-surface, single height anemometers. Extensive quality checks were performed to account for anemometer height changes, missing data, and flagged data.

Analyses focus on long-term temporal trends. Monthly, seasonal, and interannual long-term trends are analyzed utilizing low-order Gaussian moments and the Ordinary Linear Regression (OLR) technique; data autocorrelation is accounted for and additional statistical analysis is performed herein. Four sites exhibit statistically significant negative wind speed trends, 2 sites show statistically significant increased trends, and no trend is observed at 3 sites. Further data analyses include calculation of the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles of annual wind speeds and long-term temporal trends in the Weibull Probability Density Function (PDF) and the shape and scale parameters that describe the form of the distribution. The spatial variation of near-surface wind speed characteristics and regional wind speed climatology are also investigated.

Results indicate marked stilling in the annual mean, Weibull scale parameter, and 5th and 95th percentile values of wind speed at most terrestrial sites; opposite trends are generally observed at buoys and marine sites. Possible attributions of the source of the wind speed trends are also discussed.

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