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| Titel |
The motion of Hurricane-like vortices determined by multi-scale interactions between the mesoscale vortex flow and its large-scale environment: a theoretical model |
| VerfasserIn |
E. Päschke, R. Klein |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250026848
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| Zusammenfassung |
| Research in recent years have shown that multi-scale processes play a nontrivial role
in tropical cyclone development, motion and structure. For example, important
multi-scale processes that determine these vortex features arise from interactions
between the vortex flow itself, its environmental flow, the Coriolis force due to
the earth’s rotation and diabatic effects as a consequence of moisture conversion
processes occuring in convective cloud systems. Concerning the vortex motion it is well
known that the large-scale environmental flow acts as a steering flow. Beta-gyres
arising from interactions between the vortex flow and the earth’s vorticity field
contribute to a deviation of the storm track from the steering flow. Interactions
between mesoscale vortices and small scale convective systems are assumed to be
responsible for the tendency of tropical cyclones to meander about a mean path, which
can be seen in long-range observations based on modern satellite techniques. The
structure and intensity changes of tropical cyclones strongly depend from both diabatic
effects and the environmental flow. For instance, it is observed that an unfavourable
condition for a hurricane to develop or survive is given by a strong vertical shear in
the environmental flow. One common explanation for this is that the dispersion of
heat as a consequence of disruption of organized pattern of convection by strong
winds aloft is responsible for a weakening or limiting of the development of mature
storms.
We present a threedimensional model to describe the motion and structure of Hurricane
strength H1/H2 vortices. From a theoretical point of view this model gives deeper insight how
the mesoscale structure of the vortex itself affects the synoptic scale vortex motion and vice
versa, while taking the influence of a vertically sheared environmental flow and diabatic
effects due to moisture conversion processes into account. The derivation of the model
equations is based on matched asymptotic expansions which have been carried out within the
framework of an unified approach to meteorological modelling developed by Klein
(2004).
Klein, R. (2004): An Applied Theoretical View of Theoretical Meteorology. in: Applied
mathematics Entering the 21st century; Invited talks from the ICIAM 2003 Congress. SIAM
Proceedings in Applied Mathematics, vol. 116 |
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