26th Conference on Hurricanes and Tropical Meteorology

Friday, 7 May 2004: 8:00 AM
On the dynamics of two day equatorial disturbances
Napoleon I Room (Deauville Beach Resort)
Patrick T. Haertel, University of North Dakota, Grand Forks, ND; and G. N. Kiladis
Poster PDF (109.6 kB)
The speaker tests the hypothesis that the wind and temperature perturbations associated with the two day equatorial disturbance are linear responses to convective heating and cooling. Data collected during the Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment are used to construct a statistical composite of the disturbance's kinematic and thermodynamic structure. A linear model is used to simulate the atmospheric response to the composite disturbance's convective heating and cooling. The simulated temperature and wind perturbations are compared to the observed fields for the composite disturbance. The simulation is then repeated using a simplified dynamical system that includes just two vertical modes. This exercise reveals much about the dynamics of 2-day disturbances and provides a plausible explanation for the observed dispersion diagrams for a broad range of convectively-coupled tropical waves.

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