27th Conference on Hurricanes and Tropical Meteorology


Tropical cyclone inner core energetics and its relation to storm structural changes

Katherine S. Maclay, Colorado State Univ., Fort Collins, CO

Tropical cyclone intensity is traditionally based on either maximum wind speed or minimum central pressure, but the actual destructive potential is also highly dependent on the storm's structure. Therefore, it is important to understand and forecast a storm's structural evolution. In this study the inner core (0-200km) wind fields of tropical cyclones from 1995 to the present, derived from the aircraft flight level data, are used to calculate the low level inner core kinetic energy. The kinetic energies for the entire dataset are plotted against the intensities (maximum winds) revealing a general trend of kinetic energy (KE) compared to intensity. However, individual storms rarely follow this trend, and these deviations can indicate potential changes in the storm size and/or intensity. Significant changes in storm size or intensity seldom (if ever) occur simultaneously. Instead, hurricanes often either grow and weaken or maintain their intensity, or strengthen, but do not grow at the same time. A synoptic study is carried out of those storms which deviate most significantly, either positively or negatively, from the standard KE versus intensity distribution. NCEP reanalysis data are used to identify environmental conditions associated with storms that have large KE increases and those that don't. Finally, a new storm classification based on inner core KE is proposed to compliment the Saffir-Simpson scale.

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Session 2B, Tropical Cyclone Structure II
Monday, 24 April 2006, 10:30 AM-12:00 PM, Regency Grand BR 1-3

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