Open AccessEffects of Environmentally Induced Asymmetries on Hurricane Intensity: A Numerical Study
Author(s) -
Liguang Wu,
Scott A. Braun
Publication year - 2004
Publication title -
journal of the atmospheric sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.853
H-Index - 173
eISSN - 1520-0469
pISSN - 0022-4928
DOI - 10.1175/jas-3343.1
Subject(s) - inflow , outflow , troposphere , atmospheric sciences , potential vorticity , secondary circulation , tropical cyclone , environmental science , convection , hydrostatic equilibrium , context (archaeology) , climatology , thermal wind , wavenumber , mechanics , wind shear , vortex , physics , geology , vorticity , meteorology , wind speed , paleontology , quantum mechanics , optics
The influence of uniform large-scale flow, the beta effect, and vertical shear of the environmental flow on hurricane intensity is investigated in the context of the induced convective or potential vorticity asymmetries in the core region with a hydrostatic primitive equation hurricane model. In agreement with previous studies, imposition of one of these environmental effects weakens the simulated tropical cyclones. In response to the environmental influence, significant wavenumber-1 asymmetries develop. Asymmetric and symmetric tendencies of the mean radial and azimuthal winds and temperature associated with the environment-induced convective asymmetries are evaluated. The inhibiting effects of environmental influences are closely associated with the resulting eddy momentum fluxes, which tend to decelerate tangential and radial winds in the inflow and outflow layers. The corresponding changes in the symmetric circulation tend to counteract the deceleration effect. The net effect is a moderate weakening of the mean tangential and radial winds. The reduced radial wind can be viewed as an anomalous secondary radial circulation with inflow in the upper troposphere and outflow in the lower troposphere, weakening the mean secondary radial circulation.