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Feedback Between Convective Heating and Dynamics and Movements of Tropical Cyclones

Chandrasekar, A and Goswami, BN (1996) Feedback Between Convective Heating and Dynamics and Movements of Tropical Cyclones. In: Meteorolgoy and Atmospheric Physics, 61 (1-2). pp. 55-64.

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Abstract

It is shown that there exists a mechanism that can cause north-northwest movement of tropical cyclones in addition to already recognised mechanisms such as steering current and beta drift. This mechanism depends on the interaction between organised convection and dynamics. In the initial stages of formation of a cyclone, it is assumed that the hydrodynamic instabilities result in an incipient disturbance that organises some convection giving rise to a heat source. The atmospheric response to a localized heat source located off the equator in the northern hemisphere produces a low level vorticity field with a maximum in the northwest sector of the original heat source. If the 'Ekman-CISK' which depends on the low level vorticity, was the dominating mechanism for moisture convergence, the location of the heat source would move to the new location of vorticity maximum. A repetition of this process would result in a northwest movement of the heat source and hence that of the cyclone. The movement of a tropical vortex under the influence of this mechanism which depends on asymmetries created by linear dispersion of Rossby waves is first illustrated using a linear model. It is then demonstrated that this process also enhances the motion of a tropical vortex in a nonlinear model. Importance of this feedback and the resulting movements of a tropical vortex in determining the actual track of a cyclone and in bogusing an initial Vortex for prediction models are illustrated.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Springer.
Department/Centre: Division of Physical & Mathematical Sciences > Astronomy and Astrophysics Programme
Date Deposited: 20 Jul 2009 12:53
Last Modified: 19 Sep 2010 05:26
URI: http://eprints.iisc.ernet.in/id/eprint/18926

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