Document type: DU ETD
Collection: Geology Theses  
Title Synoptic Associations of Exceptional Snowfall Seasons in New England
Author(s) Hartley, Suzanne
School/Department Department of Geography
Institution University of Denver
Degree Type Doctoral
Degree Name Ph.D.
Type of Resource text
Degree Date 1996 June
Digital Origin reformatted digital
Rights Statement All Rights Reserved
Reason for Restrictions No restrictions
Type of Restriction No restrictions
Keyword(s) Geography
Genre Dissertations, Academic
Abstract Seasonal snowfall in New England has exhibited wide variations over the last few decades, the underlying causes of which have not been identified. This research examines how interactions among the large-scale atmospheric circulation and associated sea-level pressure patterns, cyclonic activity and storm track preferences, and North Atlantic sea-surface temperatures contribute to exceptional winter snowfall totals in New England. Unrotated principal components analyses of winter (December-March) precipitation, temperature and snowfall at 27 stations across New England identified regional indices of these variables. Composite anomaly maps of 700-mb heights and sea-level pressure (over North America and adjacent regions of the Pacific and Atlantic Oceans) and western Atlantic sea-surface temperatures were generated for extreme-valued winters on each of the regional climate indices. Possible associations between the regional climatic indices and indices of the Pacific-North American (PNA), North Atlantic Oscillation (NAO) and Southern Oscillation (SOl) atmospheric patterns were explored by correlation and regression analysis. The climatic, atmospheric, and oceanic data fields were analyzed in a multivariate framework to identify dominant modes of joint variability. Finally, comparisons were made of pairs of winters with similar. seasonal temperature and precipitation, but dissimilar snowfall totals. High winter snowfall totals are associated with a meridional circulation regime, as indicated by a negative NAO index and negative 700-mb height anomalies over the eastern United States. Anomalously high surface pressure over northern Canada promotes advection of cold air into the region, and the preferred storm track is along or just to the south of the New England coast. Low winter snowfall totals are associated with no unique set of circumstances, but a positive NAO index and more zonal circulation is indicated, along with weaker high pressure over Canada, and a storm track over interior New England rather than along the coast. There is no direct association with the PNA index and only a weaklag association with the SOl is indicated. In extreme southern New England, high (low) winter snowfall totals are associated with negative (positive)sea-surface temperature anomalies along the Atlantic seaboard.
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