Date of Award

2-29-2016

Document Type

Restricted Access Thesis

Degree Name

Master of Science in Applied Meteorology

Department

Department of Atmospheric Sciences and Chemistry

Thesis Advisor

Samuel T. K. Miller

Committee Member

Eric G. Hoffman

Committee Member

Barry D. Keim

Abstract

This study aimed to find relationships between planetary scale forcing patterns, specifically the PNA and NAO, and meso-alpha scale meteorological variation in sea level pressure, temperature, and vapor pressure fields in the New England region. Through Principal Component Analysis, it was found that only three Principal Components per variable were necessary to reach ~ 99% of the total variance in each of the meso-alpha meteorological fields. Correlation values calculated between the global climate indices, the PNA and NAO, and Empirical Orthogonal Functions sampled from centers of variation within the Principal Components of sea level pressure, temperature, and vapor pressure, varied greatly in magnitude. Results generated from the NAO were much larger than those found for the PNA, and were therefore the primary focus of the discussion in this study. Results showed that the first set of Principal Components for each sea level pressure, temperature, and vapor pressure accounted for the large amounts of variation in their fields, 90.40%, 95.40%, and 95.57%, respectively. Each of these Principal Components had strong, statistically significant cross-correlation values at a zero day time lag, indicating that the response in the meteorological variable field occurred at the same time as the NAO forcing pattern was present. The strongest of these cross correlations was a ~ 30% correlation between the NAO and the first Principal Component of sea level pressure. Spectral analysis of daily values of the NAO and all of the first Empirical Orthogonal Functions of the first Principal Components of sea level pressure, temperature, and vapor pressure showed clear spectral peaks above the 95%confidence level near 126 days, roughly 4 months, in all four time series. Additional results from the remaining two Principal Components of each meteorological variable, and their correlations to the NAO and associated time lags, were analyzed using a “top down” method order to find synoptic scale flow patterns involving jet stream position and amplitude, movement of surface pressures, and temperature advection that connected the phase of the planetary NAO forcing to the mesoscale response seen in the variance fields shown in the Principal Components. It was found that the position of the trough immediately upstream of the location of the NAO pressure dipole was a primary factor in the relationship between the NAO and mesoscale variation. Finally, the meteorological winter for 2004-05 was analyzed using the same methodology to provide additional results that would aid in determining if significant differences in variance patterns seen in Principal Component fields existed in one part of the year versus another. These results were listed as a starting point for further research.

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