Abstract
Improved understanding of storm-driven processes near the water-land interface (nearshore) during strong nor’easters and hurricanes is important to predicting rapid beach- and dune-erosion, and ultimately to reducing risks to populated areas. However, measurements are difficult to obtain during major storms. Terrestrial lidar (light detecting and ranging) is a remote sensing method that enables simultaneous measurements of nearshore wave-driven processes and topographic (subaerial) evolution. Lidar estimates of nearshore wave heights, setup (the wave-driven increase in the mean water level), and swash (the wave-driven shoreline fluctuations) are shown to agree well with those from buried pressure sensors during moderate wave conditions. In addition, lidar estimates of the beach and dune topography agree with GPS-based measurements. Lidar measurements collected nearly continuously during the passage of Hurricanes Joaquin (2015), Hermine and Matthew (2016), and Jose and Maria (2017) suggest setup and swash depend on the bathymetry in 1- to 5-m water depth, as well as the intertidal beach slope and offshore wave height (which are the primary variables in many existing parameterizations). The alongshore-dependent maximum shoreline water level estimated with updated parameterizations based on the lidar measurements (and offshore post-storm bathymetry) are correlated with the regions of maximum dune erosion along 500 m of the coast for each storm.
Presenter Bio
Britt Raubenheimer is a Senior Scientist at the Woods Hole Oceanographic Institution. After receiving a Bachelor's degree in Physics from Middlebury College, VT, in 1987, and spending a year skiing and hang gliding, Raubenheimer began her career in coastal oceanography working with the St. Petersburg, FL, USGS to study the processes driving the evolution of the Isle Dernieres Barrier Islands, LA. This work inspired her to get a Ph.D., which she received from Scripps Inst. Oceanography in 1996. Raubenheimer’s research interests include surf and swash-zone hydrodynamics, interactions between ocean waves and the coastal groundwater, and morphological evolution of beaches, tidal flats, and inlets. Recently, she and her students and collaborators have focused on feedbacks between oceanographical, morphological, hydrogeological, and geo-technical processes during major storms.
Publication Date
4-26-2019
Document Type
Presentation
Recommended Citation
Raubenheimer, Britt, "Lidar Measurements of Nearshore Waves, Setup, Swash, and Dune Erosion" (2019). Seminars. 279.
https://scholars.unh.edu/ccom_seminars/279