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A unified view of tropical cyclogenesis and intensification
Author(s) -
Kilroy Gerard,
Smith Roger K.,
Montgomery Michael T.
Publication year - 2016
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.2934
Subject(s) - vortex , tropical cyclogenesis , vorticity , convection , physics , cyclogenesis , tropical cyclone , barotropic fluid , potential vorticity , mechanics , atmospheric sciences , meteorology , geology , climatology , cyclone (programming language) , field programmable gate array , computer science , computer hardware
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 ( V max = 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.