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Examination of the Differences in Tropical Cyclone Pressure-Wind Relationships Among Observations, Model Analyses, and Model Forecasts

Title: An Examination of the Differences in Tropical Cyclone Pressure-Wind Relationships Among Observations, Model Analyses, and Model Forecasts.
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Name(s): Visin, Lauren, author
Department of Earth, Ocean and Atmospheric Sciences
Type of Resource: text
Genre: Text
Issuance: serial
Date Issued: 2014
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Despite significant advances in tropical cyclone (TC) track forecasting over the past few decades, intensity forecasts remain problematic, even for high-resolution computer models uniquely developed and tailored to TC prediction. This study examines the ability of two of these models, the Geophysical Fluid Dynamics Laboratory (GFDL) model and the Hurricane Weather Research and Forecasting (HWRF) model, to analyze and predict one measure of TC structure in the Atlantic Basin. Instead of more conventional evaluations based solely on a TC's maximum wind speed or minimum sea level pressure (MSLP), the relationship between these two variables is used: a TC's pressure-wind relationship (PWR), which gives a more detailed look at how well each model analyzes and forecasts TC structure. The analysis begins in 2007, the year the GFDL was initially "frozen" (development and improvements were ceased) and also the first year that the HWRF was used for operational forecasting. Comparison of both GFDL and HWRF analyses and forecasts to the National Hurricane Center's (NHC) "best track" (database of 6-hourly observations of vital statistics such as maximum wind speed and MSLP for all TCs) revealed that, while both models produced errors in their analyses and forecasts, the GFDL outperformed the HWRF in both analysis and forecasting of TC PWR's for Atlantic Basin hurricanes from 2007-2013.. There was a subsection of particularly strong TCs (maximum winds above 120kt, MSLP lower than 950mb) whose structure was forecast especially poorly. The forecast PWR's produced by the HWRF fell largely outside the "best track" for this set of intense TCs, suggesting that the structures produced by the HWRF are inconsistent with our best estimates of observations in the Atlantic Basin and given current climate conditions. The PWR distribution evolved considerably for the HWRF over time, presumably as model improvements were made (including a decrease in model gridspacing). This has led to the model analysis PWR becoming more consistent with the model forecast PWR envelope. Nonetheless, both often fall outside the best-track estimates of PWR and potential explanations for this disparity are presented.
Identifier: FSU_migr_uhm-0386 (IID)
Keywords: tropical cyclone, pressure-wind relationship, HWRF, GFDL, best track, model analyses, model forecasts, Atlantic, Dean 2007, Bill 2009
Submitted Note: A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the requirements for the degree of Honors in the Major.
Degree Awarded: Spring Semester, 2014.
Date of Defense: April 23, 2014.
Subject(s): Atmospheric physics
Atmospheric sciences
Meteorology
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_migr_uhm-0386
Owner Institution: FSU
Is Part of Series: Honors Theses.

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Visin, L. (2014). An Examination of the Differences in Tropical Cyclone Pressure-Wind Relationships Among Observations, Model Analyses, and Model Forecasts. Retrieved from http://purl.flvc.org/fsu/fd/FSU_migr_uhm-0386