The Effects of Vertical Wind Shear and Sea Surface Temperature on the Cyclogenesis and Intensity of Hurricanes
Open Access
- Author:
- Gowan, Thomas Michael
- Area of Honors:
- Meteorology
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Fuqing Zhang, Thesis Supervisor
Fuqing Zhang, Thesis Honors Advisor
Kenneth James Davis, Faculty Reader - Keywords:
- meteorology
vertical wind shear
sea surface temperature
hurricane
cyclogenesis
moisture
tropical cyclone - Abstract:
- Although great strides have been made in forecasting the track of hurricanes over the past 25 years, there has been almost no improvement in forecasting their intensities. A poor understanding of hurricane dynamics is to blame for this lack of progress. The goal of this experiment was to perform a reanalysis of Dr. Kerry Emanuel’s Maximum Potential Hurricane Intensity (MPI) Theory and to relate my findings to other studies on hurricane dynamics. The effects of the magnitude of environmental vertical wind shear and sea-surface temperatures on the formation and maximum intensities of hurricanes were investigated during the reanalysis. This was done by running simulations using the Weather Research and Forecasting Model. Simulations with environmental vertical wind shear values of 0 m/s, 1 m/s, 5 m/s, and 7.5 m/s (2 km to 12 km), with all other environmental factors held constant, were used to analyze the effects of vertical wind shear. To determine the effects of sea surface temperature, simulations with sea surface temperatures of 27°C and 29°C were run with all other environmental factors held constant. Rapid intensification was found to start once the relative humidity values exceeded 70 percent above an approximate height of 6 km in all simulations. The greater the magnitude of the environmental vertical wind shear and the lower the sea surface temperature, the longer it took for this relative humidity criteria to be reached. It was determined that the magnitude of the environmental vertical wind shear affected the timing hurricane formation, but had little effect on the maximum intensity of the hurricane. On the other hand, the sea surface temperature had little effect on the development of the hurricane, but had a noticeable effect on the maximum intensity of the hurricane.