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Curriculum Vitae |
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Home | Curriculum Vitae | Research | Presentations | Related Links | Contact Information |
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Research |
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Angela Colbert—Meteorology and Physical Oceanography |
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PhD Dissertation |
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Sensitivity of North Atlantic Tropical Cyclones to Climate Variability and Climate Change Master’s Thesis Defense was held on June 7, 2010. Master’s Thesis Approved August 2010. Committee Chair and Advisor: Dr. Brian Soden Committee Members: Dr. Christopher Landsea and Dr. David Nolan |
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Dr. Brian Soden and I investigated the relationship between tropical cyclone (TC) tracks and climatological variations in large-scale environmental parameters associated with the TC steering flow. Using the Atlantic hurricane database for 1950-2010, TCs which form in the Main Development Region (MDR) are categorized into one of three track types: straight-moving, recurving landfall, or recurving ocean. As expected, the straight moving storms are associated with a westward extension and strengthening of the subtropical high, whereas the recurving ocean storms are associated with a weakening of the high. The presence of El Niño conditions in the tropical Pacific is shown to be associated with a weakening of the high, an increase in the percentage of recurving ocean TCs, and a decrease in the percentage of recurving landfall TCs. Positive phases of the Atlantic Meridional Mode are associated with an increase in the percentage of recurving ocean TCs and a decrease in the percentage of straight moving TCs. Synthetic tracks are simulated for each storm using a beta and advection model. Sensitivity experiments using both observed and uniformly-seeded genesis locations indicate that the path of straight-moving TCs is largely a reflection of their tendency to form in the southwest portion of the MDR rather than to differences in steering flow. These experiments also suggest that the shift in TC tracks associated with El Niño/La Niña conditions is largely attributable to changes in the steering flow, whereas the track changes associated with variations in the Atlantic Meridional Mode are due to a systematic shift in genesis location. To help understand the potential impacts of rising CO2 on TCs, climate model simulations are examined for changes in track density associated with variations in the large-scale steering flow and genesis location. For the 17 model ensemble mean, changes in the winds fields and Genesis Potential Index (GPI) result in a decrease in the projected track density for the Southern Gulf of Mexico and Caribbean and increase throughout the Mid-Atlantic. When the influences of the large-scale steering flow and genesis are combined, a statistically significant decrease of 7.8% in SM TCs and increase of 6.3% in RCO TCs. |
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Publications |
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Colbert, A. J., B. J. Soden, G. A. Vecchi, and B. P. Kirtman, 2012. Impacts of Climate Change on North Atlantic Tropical Cyclone Tracks. Will be submitted to Geophysical Research Letters soon. |
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Master’s Thesis |
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Attribution of Changes in Tropical Cyclone Tracks to Climate Variability Committee Chair and Advisor: Dr. Brian Soden Committee Members: Drs. Amy Clement, Ben Kirtman, Gabriel Vecchi, and Christopher Landsea |