16D.2
Interaction of tropical cyclone outflow and an extratropical baroclinic zone: idealized simulations with MM5
Michael Riemer, NPS, Monterey, CA
A tropical cyclone (TC) may interact with the extratropical flow in a number of ways. One mechanism is the modification of the extratropical tropopause by low PV originating in the outflow of a TC. Downstream of the TC the modified tropopause may initiate explosive extratropical cyclogenesis or promote the formation of a cut-off low that may move back into the tropics exciting tropical convection or initiating tropical cyclogenesis.
In this presentation we use idealized numerical simulations with the PSU/NCAR MM5 model suite to investigate the interaction of the outflow of a TC with a midlatitude baroclinic zone. The full non-hydrostatic equations including moist processes, convective parameterization and a radiation scheme are used. The domain is a channel with periodic boundaries in the zonal direction. We initialize the model with a zonal jet at the tropopause in thermal wind balance with a meridional temperature gradient. A TC is inserted south of the baroclinic zone. The remote influence of the TC on the midlatitude is investigated relative to the separation of the baroclinic zone and the TC.
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Session 16D, Tropical cyclone extratropical transition I
Friday, 7 May 2004, 8:00 AM-9:45 AM, Napoleon III Room
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