DATA-MODEL COMPARISONS OF STORM PROCESSES DURING HURRICANE HARVEY

Katherine Anarde,Fengyan Shi,Wei Cheng,Jens Figlus,Patrick Lynett,Marion Tissier,Juan Horrillo

doi:10.9753/icce.v36v.waves.40

Abstract

During tropical cyclones, processes including dune erosion, overwash, inundation, and storm-surge ebb can rapidly reshape barrier islands, thereby increasing coastal hazards and flood exposure inland. Relatively few measurements are available to evaluate the physical processes shaping coastal systems close to shore during these extreme events as it is inherently challenging to obtain reliable field data due to energetic waves and rapid bed level changes which can damage or shift instrumentation. However, such observations are critical toward improving and validating model forecasts of coastal storm hazards. To address these data and knowledge gaps, this study links hydrodynamic and meteorological observations with numerical modeling to 1) perform data-model inter-comparisons of relevant storm processes, namely infragravity (IG) waves, storm surge, and meteotsunamis; and 2) better understand the relative importance of each of these processes during hurricane impact.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/kUizy8nK3TU

Highlights

During tropical cyclones, processes including dune erosion, overwash, inundation, and storm-surge ebb can rapidly reshape barrier islands, thereby increasing coastal hazards and flood exposure inland
IG waves were found to dominate over gravity waves during shallow flooding and overwash, consistent with the general assumption of morphodynamic models used to simulate hurricane impact (e.g., Roelvink et al, 2009)
IG energy loss across the barrier-island cut was found to be frequencydependent, with a larger percent decrease in energy flux for the lowest frequency IG waves (47-97%), below 0.01 Hz. This dominance of low frequency IG energy on the seaside of the barrier island is hypothesized to be the result of nonlinear energy transfers, energy dissipation by IG wave breaking, and wave reflection as IG waves propagated across the island during overwash

Summary

Introduction

Processes including dune erosion, overwash, inundation, and storm-surge ebb can rapidly reshape barrier islands, thereby increasing coastal hazards and flood exposure inland. INFRAGRAVITY WAVE DYNAMICS Field measurements of wave fields on either side of two barrier islands along the Texas Gulf coast (U.S.A) during Hurricane Harvey (2017) revealed that IG waves (0.0030.04 Hz) were an important component of the nearshore wave field during this relatively low-surge event.

Results

Conclusion