The control of tropical sea surface temperatures on tropical cyclones in the Northern Hemisphere
Tropical cyclones (TCs) can cause severe damages (primarily via high winds, heavy rainfall, and storm surge) to coastal communities when making landfall, and their induced damages have been increasing in recent decades, attracting more attention to a better understanding and prediction of TC activit...
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| Other Authors: | , , , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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University of North Carolina at Chapel Hill Graduate School
2023
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| Online Access: | https://doi.org/10.17615/43ec-0y51 https://cdr.lib.unc.edu/downloads/rr172750b?file=thumbnail https://cdr.lib.unc.edu/downloads/rr172750b |
| Summary: | Tropical cyclones (TCs) can cause severe damages (primarily via high winds, heavy rainfall, and storm surge) to coastal communities when making landfall, and their induced damages have been increasing in recent decades, attracting more attention to a better understanding and prediction of TC activity. Given the strong modulation of TCs by their large-scale atmospheric environment that is in turn tied to the variability of tropical sea surface temperatures (SSTs), a thorough and in-depth understanding of the connections between TC activity and tropical SSTs is crucial to improving TC prediction. The focus of my dissertation is to provide a comprehensive examination of the modulation of basin-wide TC genesis frequency (TCGF) as well as TC genesis density in the Northern Hemisphere by tropical SSTs using both observations and high-resolution atmospheric simulations from the Database for Policy Decision Making for Future Climate Change (d4PDF) and Coupled Model Intercomparison Project Phase 6 (CMIP6) High Resolution Model Intercomparison Project (HighResMIP).The first part quantifies the contributions of tropical SST variations, represented by the seven leading modes extracted using the empirical orthogonal function analysis, to the interannual-to-decadal variability in TCGF over the Northern Hemisphere ocean basins. These modes account for approximately 58%, 50%, and 56% of the variance in basin-wide TCGF during 1969–2018 in the North Atlantic (NA), northeast Pacific (NEP), and northwest Pacific (NWP), respectively. In the second part, using both observations and atmospheric simulations from the CMIP6 HighResMIP, we show that El Niño–Southern Oscillation (ENSO) has been playing a substantially increasing role in modulating TCGF in the tropical NA, NEP, and NWP, particularly after the 1990s. In the last part, a large ensemble of high-resolution atmospheric simulations from the d4PDF is employed to characterize the spatial structure and temporal evolution of TC genesis density in the NWP and explore the seasonal ... |
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