Ph.D. Defense
Name: Kyungmin Park
Title: Drivers of Coastal Sea Level and Flooding along the East Coast of the United States
Date & Time: Monday, November 21, 2022, 1:00 pm
Location:
In person ES&T L1114
Virtual https://gatech.zoom.us/j/7184656594?pwd=eXdidmkzNm40ekxhcHFIc2dkdmNLQT09
Thesis Advisor: Dr. Emanuele Di Lorenzo (EAS)
Committee Members: Dr. Kevin A. Haas (CEE), Dr. Alexander Robel (EAS), Dr. Joel Kostka
(BIOS), Dr. Tal Ezer (ODU), Dr. Nadia Pinardi (UB)
Summary
Coastal cities and communities are on the frontline as sea-level rise induced by climate change
expands the oceans and re-draws the maps of the coastline. Despite the emerging threats of sealevel
rise and flooding, the current water level observational networks and the modeling
approaches for the U.S. East Coast are inadequate to resolve the combined effects of watershed
loading, the spatiotemporal variations of the extreme water level, and the compound flooding at
the scale of rivers, tributaries, creeks, and City’s block during hurricane events. These limitations
pose challenges for understanding, predicting, and mitigating the regional and city-scale impacts
of climate extremes and flooding on coastal communities. They also imply that coastal decisionmakers
and planners are not equipped with adequate tools to inform coastal protection and
management strategies. The main goals of this thesis are to develop large-scale, three-dimensional,
high-resolution coastal models to overcome the limitations of existing technologies and use them
to diagnose the role of extreme water level drivers along the East Coast of the United States.
Accordingly, chapter 1 introduces the drivers of extreme water levels along the U.S. East Coast.
In chapter 2, I present a new modeling system that has been implemented to deliver a 3-day forecast
system in Chatham County (GA). This system that has been operational since 2019 is currently
being used by the Chatham Emergency Management Agency and the City of Savannah to design
new emergency protocols and advance a city-wide resilience planning process. In Chapter 3 I use
this modeling system to conduct a series of hurricane hindcast and sensitivity experiments to
examine the relative roles of extreme water level drivers during major coastal storms and quantify
its contributions to the spatial and temporal patterns of extreme water levels. Specifically, this
chapter investigates the important oceanic responses to hurricane forcing (e.g., change in Gulf
Stream, Ekman transport and Coastally Trapped Waves) compared to the local atmospheric wind
and pressure forcing on the U.S. southeast coast. In Chapter 4, I expand the numerical modeling
capability and domain over the entire U.S. East Coast to examine the persistent high water level
following a hurricane. I find that baroclinic drivers linked to an oceanic adjustment cause the
abnormal increase in water levels even after hurricanes have dissipated, which is twice as high as
the sea-level rise in 100 years (≈34 cm) on the Georgia coast. In Chapter 5, I conclude the works
by discussing how these new insights into the multiple drivers of abnormal water levels, both
during and after hurricane events, fill critical knowledge gaps and data needs necessary to inform
best practices to scientists, engineers and policymakers.