P2.20 The Contribution of the Non-axisymmetrical Component in Inner Core to the Maximum Intensity of the Simulated Tropical Cyclones

Wednesday, 18 April 2012
Heritage Ballroom (Sawgrass Marriott)
Satoki Tsujino, Nagoya University, Nagoya, Japan; and K. Tsuboki

Handout (790.2 kB)

This study was to quantitatively estimate the contribution of the non-axisymmetrical component to the maximum intensity (maximum wind) of numerically simulated tropical cyclones (TCs) having the different maximum intensity, by analyzing the angular momentum budget of axisymmetrical wind.

In this study, the TCs are simulated using the Cloud Resolving Storm Simulator (CReSS model) which was developed in Hydrospheric Atmospheric Research Center (HyARC).

To analyze the TCs having the different maximum intensity, this study performed the experiments for the some values of the momentum and heat exchange coefficients.

Because these coefficients have sensitivity for the TC's maximum intensity, according to Bryan and Rotunno (2009).

The method of the analysis of the angular momentum budget was used in the method of Wang (2002), except for z-coordinate version.

The result of the analysis of the angular momentum budget shows that the acceleration of axisymmetrical flow due to the asymmetrical component near the radius of maximum wind (RMW) is negative (i.e. decelerating the axisymmetrical flow), while the acceleration due to axisymmetrical component is positive (i.e. accelerating the axisymmetrical flow).

For all TCs in this study, the magnitude of the deceleration due to asymmetrical component near the RMW is about 10% that of the acceleration due to axisymmetrical component.

It shows that the maximum deceleration due to the asymmetrical component tend to vary with the maximum intensity (i.e. axisymmetric wind).

In this study, the Vortex Rossby Wave with the low wave number is thought as the asymmetrical component in inner core.

It shows that the azimuthal propagating speed is approximately the same speed of the theoretical result of Montgomery and Kallenbach (1997), using the Fourier analysis.

The future subject is to show how (or why) the deceleration due to asymmetrical component relate to the maximum intensity.

- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner