Physically based storm transposition of four Atlantic tropical cyclones

Area of Science:

• Atmospheric Science
• Meteorology
• Climate Modeling

Background:

• Tropical cyclones pose significant risks due to extreme precipitation events.
• Accurate simulation of tropical cyclone impacts, particularly precipitation, is crucial for disaster preparedness.
• Existing storm transposition methods may lack physical basis, affecting simulation accuracy.

Purpose of the Study:

• To present a novel, physically based storm transposition method for tropical cyclones.
• To conserve fundamental physical properties (mass, momentum, energy) during storm transposition.
• To assess the impact of spatial shifting of tropical cyclone initial conditions on precipitation fields and tracks.

Main Methods:

• Utilized a regional atmospheric model for reconstructing precipitation depth fields.
• Implemented a physically based storm transposition by spatially shifting the tropical cyclone vortex in initial conditions.
• Applied the method to four historical hurricanes (Floyd, Frances, Ivan, Isaac) impacting the United States.

Main Results:

• Physically based storm transposition significantly altered precipitation depth fields in structure and intensity.
• Tropical cyclone tracks exhibited high sensitivity to initial condition changes, a characteristic of nonlinear dynamics.
• Small shifts in the initial vortex location led to substantially different tracks and precipitation distribution.

Conclusions:

• The developed physically based storm transposition method provides a more accurate simulation of tropical cyclone precipitation.
• This method allows for repositioning precipitation fields over target areas by adjusting initial conditions.
• Findings highlight the importance of precise initial conditions for predicting tropical cyclone impacts.