A unified view of tropical cyclogenesis and intensification
Smith, Roger K.
Montgomery, Michael T.
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Idealized high-resolution numerical simulations of tropical cyclogenesis are presented in a model that represents deep convection by a warm rain process only. Starting with an initially weak, cloud-free, axisymmetric warm-cored vortex (maximum wind speed 5 m s−1 at a radius of 100 km), rapid vortex intensification begins after a gestation period on the order of 2 days. From a three-dimensional perspective, the genesis process is similar to that in the rotating convection paradigm for vortex intensification starting with a much stronger initial vortex (Vmax = 15 m s−1). The patterns of deep convection and convectively amplified cyclonic relative vorticity are far from axisymmetric during the genesis period. Moreover, the organization of the cyclonic relative vorticity into a monopole structure occurs at relatively low wind speeds, before the maximum local wind speed has increased appreciably. Barotropic processes are shown to play an important role in helping to consolidate a single-signed vorticity monopole within a few hours near the intensification begin time. The rotating convection paradigm appears adequate to explain the basic genesis process within the weak initial vortex, providing strong support for a hypothesis of Montgomery and Smith that the genesis process is not fundamentally different from that of vortex intensification. In particular, genesis does not require a ‘trigger’ and does not depend on the prior existence of a mid-level vortex.
Quarterly Journal of the Royal Meteorological SocietyThe article of record as published may be found at http://dx.doi.org/10.1002/qj.2934
Showing items related by title, author, creator and subject.
Kilroy, Gerard; Smith, Roger K.; Montgomery, Michael T. (Wiley, 2017-01);Idealized high-resolution numerical simulations of tropical cyclogenesis are presented in a model that represents deep convection by a warm rain process only. Starting with an initially weak, cloud-free, axisymmetric ...
Persing, J.; Montgomery, M.T.; McWilliams, J.C.; Smith, R.K. (Copernicus Publications, 2013);We present the results of idealized numerical experiments to examine the difference between tropical cyclone evolution in three-dimensional (3-D) and axisymmetric (AX) model configurations. We focus on the prototype ...
Bell, Michael M.; Montgomery, Michael T. (American Meteorological Society (AMS), 2010);Observations from the Pre-Depression Investigation of Cloud Systems in the Tropics (PREDICT), Genesis and Rapid Intensification Processes (GRIP), and Intensity Forecast Experiment (IFEX) field campaigns are analyzed to ...