The interannual variability of storms associated with extratropical and tropical climate forcings in the southeastern United States and a loss assessment, 1990 to 1998.

摘要

This research examined the relationships between selected tropical and extratropical long-wave teleconnection patterns, synoptic-scale storm intensities and frequencies, and mesoscale storm frequencies. Five teleconnection patterns were selected: the Pacific/North American (PNA) index; the North Atlantic Oscillation (NAO); the North Pacific Oscillation (NPO); the West Pacific (WP) index; and the Southern Oscillation Index (SOI).; Cumulative annual values for the atmospheric indices were calculated by totaling the average monthly values for each index by calendar year from January to December. Similarly, the Laplacian of central pressure, a measure of storm intensity, was averaged by month and those values were totaled for the year. Synoptic-scale and mesoscale storm frequency was calculated by counting the number of storms in the Southeast from 1990 to 1998.; Spearman Rank Order Correlation statistic was used to answer both research questions: (1) Are intensity changes in selected global-scale, atmospheric teleconnection indices related to intensity and/or frequency changes in synoptic-scale and mesoscale storms in the US from 1990 to 1998? (2) Are synoptic-scale storm intensities and frequencies are related to the frequency of damaging synoptic-scale and mesoscale storms in the southeastern US from 1990 to 1998? Any correlation value exceeding ±0.7 was considered to be significant at the 95% confidence level.; The North Atlantic Oscillation was shown to be more indicative of storm intensity, storm frequency, and the number of damaging storms in the Southeast USA from 1990 to 1998 than all other indices. The Southern Oscillation Index is significantly correlated with synoptic-scale storm intensity and the North Pacific index is significantly associated with synoptic-scale storm frequency. None of the other indices investigated had statistically significant results.; The results of this study suggest that more attention be given to the North Atlantic Oscillation and the North Pacific pattern as possible means of better predicting weather events. It is suggested that this study be expanded to include all available data prior to 1990. If it is shown that the relationships between meteorological variables and the atmospheric indices are valid in the years before 1990, the study should be expanded geographically to include other areas of the continental United States.