84th AMS Annual Meeting

Wednesday, 14 January 2004
The impact of teleconnection patterns on air mass frequency and character in North American winters
Hall 4AB
Melissa Lynn Malin, Center for Climatic Research, University of Delaware, Newark, DE
An integral part of synoptic climatological research is aimed at understanding the ways in which teleconnection patterns influence the North American weather and climate system. An important role within the field of synoptic climatology includes correlating teleconnection phases to the cyclical nature of other phenomena. Teleconnections are usually responsible for anomalous weather conditions that not only span great distances but also can persist for several years. In North America, it is widely believed that teleconnection patterns influence the wavelength and amplitude of passing ridge-trough systems along with vertical motion differentials occurring in the atmosphere. The positioning of these systems across the continent determines where the more likely intrusion of particular air masses will occur throughout the year.

This research examines the impact of four teleconnection patterns (the El Niņo Southern Oscillation, Pacific Decadal Oscillation, Pacific/North American pattern , and North Atlantic Oscillation ) on air mass character and frequency in northern United States and southern Canadian winters, from 1948 to the present. Character and frequency differentials are acquired and tested for statistical significance. Results are spatially interpolated and inputted into GIS maps to assess the spatial variability between sets of normal air mass conditions and positive/ negative teleconnection phases. Finally, the modification of air mass character and frequency due to climate change is examined. Recent winters have been compared to those of 40-50 years ago with similar teleconnection and wave patterns to determine whether notable air mass changes have occurred.

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