Enso Influence on Atlantic Basin Tropical Cyclone Regional Landfall Counts
Open Access
- Author:
- Imhoff, Kyle Alexander
- Graduate Program:
- Meteorology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- April 30, 2014
- Committee Members:
- George Spencer Young, Thesis Advisor/Co-Advisor
- Keywords:
- El Nino
Southern Oscillation
Tropical Cyclones
Atlantic
Self-organizing maps
regional
landfall
climatology
hurricane - Abstract:
- A climatological analysis investigates Atlantic basin tropical cyclone tracks and landfall patterns and their connections to synoptic patterns and the phase of the El Nino-Southern Oscillation (ENSO). Thirty-three years (1979-2011) of tropical cyclone activity are examined using storm positions from the North Atlantic Hurricane Database. The ENSO phase is determined by the Oceanic Nino Index, and mean sea level pressure (MSLP) patterns are analyzed using the National Center for Environmental Prediction Reanalysis 2 dataset. A cluster analysis technique, called self-organizing maps, is performed on the MSLP patterns across the North Atlantic Basin at the time when tropical cyclones made landfall. From this technique, statistical comparisons are made between landfall patterns during each ENSO phase and a computed climatological average for each cluster. Results of this analysis indicate that two distinct high pressure centers are present during La Nina events – one center over the subtropical Atlantic and one over the central United States (US). Only one large high pressure center is present over the Atlantic during El Nino events. Because of these pressure patterns, during La Nina events when more tropical cyclones are favored to form over the Atlantic Basin, greater increases in landfall probabilities exist for Canada and Central America than in the US. During El Nino events when tropical cyclones are less likely to form, smaller decreases in landfall probabilities exist for the US than for Canada and Central America. Thus, landfall activity in the US is less influenced by the ENSO phase than the remainder of the continent.