Tropical Cyclone Hazards in Relation to Propagation Speed

• Main Author: Huang, Jiehao
• Format: Thesis
• Language: English
• Published: CUNY Academic Works 2020
• Subjects: Tropical Cyclone; propagation speed; intensity; Analysis; Applied Mathematics; Applied Statistics; Geology; Longitudinal Data Analysis and Time Series; North Atlantic
• Online Access: https://academicworks.cuny.edu/cc_etds_theses/826; https://academicworks.cuny.edu/cgi/viewcontent.cgi?article=1890&context=cc_etds_theses

As the population and infrastructure along the US East Coast increase, it becomes increasingly important to study the characteristics of tropical cyclones that can impact the coast. A recent study shows that the propagation speed of tropical cyclones has slowed over the past 60 years, which can lead to greater accumulation of precipitation and greater storm surge impacts. The study presented herein is meant to examine and analyze the relationships that exist between the propagation speed of tropical cyclones, their surface wind strength, displacement angles, and cyclone averaged winds. This analysis is focused on tropical cyclones spanning from 1950-2015 in the North Atlantic. We first confirm with other research that the temporal trends of intensity of tropical cyclones do not show a consistent temporal signal over the entire record. This inconsistency may be due to the lack of data in the era before satellite-retrieved weather data was readily available. A correlation analysis is applied for the propagation speed versus intensity of cyclone to examine which height of the wind best affect the cyclone propagation. The results show a strong positive correlation between propagation speed and cyclone averaged wind at 700-hPa with a size of 150 km radius away from storm center, especially when the cyclone moves eastward. To aid in the study of the movement of cyclones, a new metric is developed: the displacement angle analysis of cyclone paths. This metric examines the abrupt change of angles for each successive two instance cyclones, and the time series of displacement angle analysis shows a significant increasing trend due to the high frequency of top 10% events in recent decades. This research highlights an interesting question about the trends in tropical cyclones over the past 60 years related to the subtle differences in the behavior of the propagation speed and its wind strength.