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Abstract The dissipation of wave energy is important to nearshore circulation and beach profile evolution. Here, radar measurements of wave dissipation at the water surface across the surfzone are used to estimate water velocities and sediment transport in the lower water column to drive an energetics model for morphological change. The radar‐driven model accurately simulates both the 25‐m onshore and the 50‐m offshore migration of a sand bar observed on an Atlantic Ocean beach with a single set of calibration coefficients. Similar to previous studies, wave asymmetry dominated during mild wave conditions when the bar migrated shoreward, and undertow dominated during energetic conditions when the bar migrated seaward. Model results were improved by accounting for both wave bottom boundary layer effects near the sand bar (especially during onshore migration) and the vertical extent of sediment suspension in the undertow transport (especially during offshore migration). 

This dataset contains radar-derived surfzone surface roller energy flux and dissipation data used in: Grossmann, F., Streßer, M., Raubenheimer, B. & Elgar, S. (2025). Radar estimates of surfzone dissipation drive a morphological evolution model, Manuscript submitted for publication. The study investigates the morphological evolution of a sandbar between consecutive bathymetric surveys in environmental conditions that cause onshore (denoted ON1 and ON2) and offshore (denoted OFF) bar migration. The coherent marine radar (CMR) deployment at the U.S. Army Corps of Engineers Research and Development Center's Field Research Facility (FRF) in Duck, North Carolina, USA, was initiated as part of the During Nearshore Event Experiment (DUNEX). A detailed description of the deployment setup is available in: Streßer, M., Collins, C. O. I., Lund, B., Humbertson, J., Horstmann, J., Carrasco, R., Spore, N., & Brodie, K. (2024). Coherent Marine X-Band Radar Deployment during DUNEX (Techreport No. ERDC/CHL TR-24-16). US Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory. https://doi.org/10.21079/11681/49218 The data was processed using the methodology described in: Streßer, M., Horstmann, J., & Baschek, B. (2022). Surface Wave and Roller Dissipation Observed With Shore-Based Doppler Marine Radar. Journal of Geophysical Research: Oceans, 127(8), e2022JC018437. https://doi.org/10.1029/2022JC018437 Specifically, the roller energy was computed using equation 14, flux of roller energy using equation 15, and the dissipation of roller energy using equation 17 of Streßer et al. (2022). The radar roller dissipation scaling factor was set to Br = 0.013. The roller slope parameter was set to βs = 0.1. All quantities are computed from 7-min long coherent radar records with a static antenna pointing to 60° from North (nautical convention, i.e. counter-clockwise from North). The radar was located at Latitude/Longitude = 36.1822972/−75.7511785. The antenna was located at an elevation of approx. 15 m (relative to NorthAmerican Vertical Datum of 1988).   As in Streßer et al. (2022), roller energy and dissipation were smoothed using a 5-point moving average filter (in space) to mitigate measurement noise. The unsmoothed raw values are also included in the data set.   Variables in CMR data structure: t: UTC time in Matlab datetime format r: range, i.e. distance from radar antenna [m] xFRF: cross-shore coordinate of FRF local reference system [m] yFRF: alongshore coordinate of FRF local reference system [m] Er: roller energy [J m^(-2)] Fr: flux of roller energy [W m^(-2)] Dr: roller dissipation [W m^(-2)] Er_raw, Fr_raw, and Dr_raw are raw quantities before spatial smoothing.The data is stored in Matlab® v7.3 format.