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SEMINAR: MPO Seminar: Mike McGauley, TODAY, at 10:30 a.m., MSC 343

From: Sandrine Apelbaum <sapelbaum@rsmas.miami.edu>
Subject: SEMINAR: MPO Seminar: Mike McGauley, TODAY, at 10:30 a.m., MSC 343
Date: Fri, 17 Feb 2012 08:33:42 -0500

MPO STUDENT SEMINAR

 

 

Mike McGauley


 Title: "Analyzing environmental favorableness of tropical cyclogenesis 

by examination of threshold parameters"


Friday, February 17, 10:30 a.m.

 MSC 343


Abstract:

A unique approach is proposed that utilizes threshold values in potential intensity, wind shear, vorticity, and saturation deficit. Prior statistical methods generally involve creating an index or equation based on averages of important meteorological parameters for a given region. The new method assumes there exist threshold values for each important parameter for which cyclogenesis is unlikely to develop. This technique is distinct from previous approaches that seek to determine how each of these parameters interdependently favors cyclogenesis. For predicting regional and monthly variations in frequency of genesis, this approach is shown to generally meet or exceed the predictive skills of earlier statistical attempts with some failure only during several off-season months. This method also provides a more intuitive rationale of the results.

An attempt is also made to provide a physical explanation as to why one of the threshold parameters, namely vorticity, inhibits cyclogenesis below a certain value. By analyzing model simulations at various latitudes, budgets of water vapor, mass and momentum reveal that below the threshold vorticity the storm does not have enough inertial stability to allow for development even though there is adequate inward advection of water vapor. Interestingly, beyond approximately 15 degrees latitude, the time for storm development is not accelerated even with additional absolute vorticity. This is due to the fact there is less advection of water vapor at higher latitudes due to a decrease in Ekman transport.


Sandrine Apelbaum
Meteorology and Physical Oceanography 
Rosenstiel School of Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami, FL 33149-1098
Tel     (305) 421-4057
Fax     (305) 421-4696