Jason Godwin's Research Projects

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Observations of Supercell Structures in Hurricane Irene (2012)

On 27 August 2011, Hurricane Irene made landfall on the Outer Banks of North Carolina. A team of researchers from the University of Oklahoma with mobile radars intercepted the storm, obtaining a vast amount of dual-polarimetric, Doppler radar data. Several small, supercell-like structures embedded in Irene's outer rainbands moved very near the radar sites. Some of these storms produced tornadoes. In this research, the storm environment which favored the development of the tropical cyclone-induced tornadoes (TCs) was examined. The results were compared to the findings in McCaul (1991), and a dual-Doppler wind retrieval on one of these supercell-like structures was performed. It was determined that (1) the storm environment was very similar to that described by McCaul (1991) and (2) there is a correlation between the location/intensity of the updraft and a differential reflectivity (ZDR) ring that was observed multiple times by dual-polarimetric radars in the area. In comparison to McCaul and Weisman's (1996) simulation of strong vertical velocities below 1.5 km of the supercell's updraft exceeding the magnitude of Great Plains storms, the dual-Doppler analysis was able to verify this claim. It is likely that these strong low level vertical velocities are the cause for the coalescence of raindrops in a stratiform environment, hence the cause for the ZDR rings. Later work in this field could include an improved dual-Doppler wind retrieval, numerical simulations, and microphysical modeling.

  • Team members: Jason Godwin, Brian Squitieri, and Bryan Trachier
  • Mentor: Dr. Michael Biggerstaff
Final Paper

Multidimensional Radar Analysis of Summertime Pulse Thunderstorms (2011)

This presentation was given at the National Oceanic and Atmospheric Administration (NOAA) headquarters in Silver Spring, Maryland on August 2, 2011. The research was conducted between May and August of 2011 at the National Weather Service Weather Forecast Office in Charleston, South Carolina under the supervision of Science and Operations Officer Frank Alsheimer. Special thanks to the NWS Charleston, SC, NOAA's Warning Decision Training Branch (WDTB), the National Severe Storms Laboratory (NSSL), and the NOAA Office of Education.

Abstract: One of the most difficult aspects of weather forecasting in the southeastern United States is the prediction and warning of severe pulse thunderstorms. Pulse thunderstorms are typically short-lived and disorganized, but can produce severe damaging winds and/or large hail within as little as 20-30 minutes of first being detected by radar. The purpose of this research was to document the evolution of a pulse thunderstorm and develop a warning criteria for large hail detection.

Download the Presentation: PDF Format (2.9 MB, .pdf)


MATLAB Dual-Polarimetic Radar Project (2011)

This project was my term project for METR 4330 (Information Technology Skills for Meteorologists). This independent-learning course was supervised by Dr. Brian Fiedler at the University of Oklahoma. This program was also created for use at the Radar Operations Center in Norman, Oklahoma. I received a grade of "A" on this project as well as the course.

Abstract: The MATLAB software was used to develop a program that will plot an average reflectivity (Z) versus differential reflectivity (ZDR) for dual-polarimetric radar. This program serves two purposes: exploring the expected values of ZDR for a given value of Z and determining the calibration of the ZDR by testing it against known values.

Project Webpage


A Case Study on Diurnal Boundary Layer Evolution (2010)

This paper (unpublished) was my term project for METR 3613 (Meteorological Measurement Systems). This course was taught by Dr. Petra Klein at the University of Oklahoma. Team members included fellow School of Meteorology students Sam Irons, Charles Kuster, Nathan New, and Stefan Rahimi. While we all worked on the project together, each student submitted their own paper. The purpose of this project was to learn about a specialized meteorological measurement system (in our case, upper-air observations) and to be introduced to the research process and the process of writing a scientific paper. My grade on this paper was a 95% A.

Abstract: In this project, data from four different soundings over Norman, Oklahoma from September 17, 2010 was used to evaluate changes in the boundary layer. The boundary layer was identified by determining the height of an inversion layer and other thermal properties of the low levels of the atmosphere. It was determined that as the day progressed, the boundary layer deepened as the inversion layer rose and low-level lapse rates steepened. The depth of the boundary layer has important applications in forecasting daily weather conditions and severe weather phenomena.

Sounding Paper for METR 3613