Scientific Research

MISSION #1: Conduct observational, theoretical, and experimental research to generate new knowledge and advance the frontiers of meteorology by leveraging multiple data sources and expertise in the field. Maintain professional collaborations with organizations and agencies in all sectors.

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Research in atmospheric dynamics often requires the use of multivariate and differential calculus equations as an application of fluid dynamics theory.





QUICK LINKS: Ongoing Research | Field Experience | Other Previous Research




Ongoing Research

 

Upper-Tropospheric Influences on Tropical Cyclone Intensity

The objective of my current meteorological research, in fulfillment of my Ph.D. dissertation requirements at the University of Hawai’i, is to improve our scientific understanding of the dynamics that govern tropical cyclone intensity change, particularly with regard to upper-tropospheric influences. Of interest is the long-known but poorly-understood and sometimes controversial upper-tropospheric atmospheric phenomenon called the Tropical Upper-Tropospheric Trough (TUTT). The TUTT is a semi-permanent, mid-oceanic feature of the monthly mean climatological tropical circulation. Within these troughs, concentrated areas of vorticity often develop, which persist as upper-tropospheric, cold-core cyclones, or “TUTT cells” (TUTTcs). Since the early years of atmospheric streamline analyses over the tropical and subtropical oceans, the TUTT has been observed to play an important role in the synoptic and large-scale interactions between the tropics and mid-latitudes. Tropical cyclones (TCs) are routinely influenced by upper-tropospheric phenomena, which have been shown to affect TC development and behavior, particularly TC intensity change. Operational TC forecasters have frequently expressed uncertainty in TC intensity forecasts when a TUTT or TUTTc is nearby. As we seek to advance our understanding of TCs and to improve TC track and intensity forecasting in an era of high-resolution global modeling, interactions between TCs and TUTTcs must be objectively quantified. There have been many studies about mid-latitude upper-tropospheric trough/low interaction with TCs, but few have focused on TUTTs/TUTTcs. It is evident that the westward motion of TUTTcs and their separation from mid-latitude westerlies by the subtropical ridge can contribute to their longevity and subsequent interaction time with TCs. Furthermore, TCs are typically recurving in the case of mid-latitude trough interaction, whereas TUTTc interaction may occur at lower latitudes, where other conditions (e.g., sea surface temperatures, ocean heat content) support more rapid intensification. To better understand these relationships, an objective TUTTc tracker is currently being developed for use with NWP analyses, forecasts, and climate simulations. For a semi-daily discussion of TUTTc interactions with TCs, please see my 2012 TUTT Log.

Collaborators: UH Department of Meteorology | NOAA Earth System Research Laboratory | U.S. Navy/Air Force Joint Typhoon Warning Center

 

Cities and Storms

In addition to atmospheric dynamics, another pressing area of research rests at the intersection of meteorology, urban planning, and hazards risk reduction. Each year, weather is responsible for hundreds of fatalities and hundreds of billions of dollars of the U.S. economy. As urbanization and globalization continue, together with coastal vulnerability in an era of rising sea levels, we face a unique public safety challenge that requires the cooperation of the physical, social, and policy science communities. Locally, extreme events such as the El Reno, Oklahoma tornado of May 31, 2013 painfully illustrate the challenge of urban resilience in the face of natural hazards. Research is currently being conducted into the unique combination of meteorological conditions and traffic management issues ahead of the tornado. In part because of a controversial call by some broadcast meteorologists to evacuate ahead of the storm, highways came to a standstill ahead of what became the largest tornado in recorded U.S. history. Seven out of nine fatalities occurred in vehicles.

Collaborators: National Disaster Preparedness Training Center | UH Department of Urban & Regional Planning | National Domestic Preparedness Consortium




Field Experience

 

Owen_shipDYNAMO: Dynamics of the Madden-Julian Oscillation

In the late fall of 2011, I had the privilege of spending over a month at sea in the equatorial Indian Ocean to participate in the DYNAMO Field Experiment. I served as one of two radar scientists responsible for the operation of the TOGA C-band Doppler radar aboard the ship R/V Roger Revelle as part of an international effort to better understand the convective-scale and boundary layer evolution of the Madden-Julian Oscillation (MJO). The objective of this project was to collect data through a multi-platform approach to improve our understanding of the genesis of convection associated with the MJO. I was stationed on the ship for 5 weeks in the equatorial Indian Ocean from November into December 2011. The extended period at sea without seeing any land was an adventure in itself, which I captured in a series of personal essays. For more information, please visit the DYNAMO website.

 

vortex-1VORTEX 2: Verification of the Origins of Rotation in Tornadoes Experiment 2

In the spring of 2009 and 2010, I was put in charge of navigating an NSSL mobile mesonet to collect data within tornadic supercell thunderstorms for the Verification of the Origins of Rotation in Tornadoes Experiment 2 (VORTEX 2). The purpose of the project was to help us better understand the dynamics of tornadogenesis, particularly the source of the strong, low-level vorticity in supercells that can result in tornadoes. Under the guidance of Dr. Paul Markowski and Dr. Yvette Richardson, the project afforded me the opportunity and responsibility to make critical, sometimes life-or-death decisions under time pressure for the sake of scientific data collection. No other project has been as physically and mentally demanding, and the leadership and teamwork skills that I gained from this experience on the scientific frontier was priceless. For more information, please visit the VORTEX2 website.

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Ike_rainIke_deployment_radarHurricane Ike (2008) Radar Deployment

In the fall of 2008, I participated in a University of Oklahoma (OU) and National Severe Storms Laboratory (NSSL) intercept of Hurricane Ike at landfall. Our team deployed the NO-XP Dual-Polarization Mobile Doppler Radar on its “maiden voyage” to study the inner rainbands and boundary layer structure of the hurricane. Under the direction of Dr. Michael Biggerstaff, we spent a full night at the Brazoria County Airport collecting data while getting pummeled by wind-driven rain at hurricane force. It was definitely a night that I will never forget.

 




Other Previous Research

 

“Hurricane Graveyard” in the eastern Caribbean

As part of the senior honors thesis program at Cornell University, I investigated the long-known but mysterious minimum in tropical cyclogenesis in the eastern Caribbean Sea. By analyzing wind data from NCEP/NCAR Reanalysis and conducting statistical tests, I identified pre-existing low-level divergence in the region associated with the Caribbean Low-Level Jet as a contributing factor. This research was peer-reviewed and published in the February 2010 issue of the Bulletin of the American Meteorological Society and has been widely cited by other research papers and even in public blogs. I was awarded the Father James B. Macelwane Award by the American Meteorological Society for best undergraduate research paper in the nation.

 

Supercells in a High-Resolution Hurricane Simulation

I investigated the structure and evolution of a supercell in the outer-rainband region of a high-resolution, numerically simulated tropical cyclone (Dx = Dy= 667 m) as part of my degree requirements toward an M.S. in Meteorology at the University of Oklahoma. The simulations were conducted using the three-dimensional, non-hydrostatic Straka Atmospheric Model. The simulated supercell structures resembled observed tropical cyclone supercells, and I hypothesized that vertical tilting of baroclinically-generated horizontal vorticity may be an important factor in the development of TC supercells.

 

Numerical Model Diagnostics for Hurricane Ike (2008)

I spent the summer of 2010 with the Forecast Applications Branch within the Global Systems Division of NOAA Earth System Research Lab in Boulder, CO writing and organizing GrADS scripts for use with Diapost, an HWRF visualization tool from the Hurricane Research Division in Miami, FL, to analyze the structure of Hurricane Ike (2008). This was in support of the Unmanned Aerial Systems – Observing System Simulation Experiment (UAS-OSSE), a project aimed at improving our observations of hurricanes and the dynamics behind rapid intensification.

 

Quantitative Precipitation Estimation

I was selected as a NOAA Hollings Scholar during the first year of the program and was assigned to the NOAA National Severe Storms Lab in Norman, OK in the summer of 2006. I worked with the hydrometeorology group by assimilating 2003-2006 rain gauge data for use in the lab’s Tar River Basin project of North Carolina (Coastal and Inland and Flood Observation and Warning Project) and evaluated biases in the lab’s Quantitative Precipitation Estimate products through a case study.