High-Resolution Airborne Light Detection and Ranging (LiDAR) Scans of the Bristol Channel and Severn Estuary, UK (April - June 2023).

This dataset contains high-resolution water surface elevation (WSE) measurements from five airborne LiDAR surveys of an estuarine system conducted between April and June 2023. The surveys were strategically timed to coincide with Surface Water and Ocean Topography (SWOT) satellite overpasses and captured a comprehensive range of tidal conditions, spanning from - 5.1 m to + 5.4 m relative to the EGM2008 geoid during both flood and ebb tides. Two Leica LiDAR systems were deployed: the Hyperon system for three longitudinal flights (May 16, June 24, June 29) covering 55 km along the estuary axis, and the T500 system for two cross-estuary flights (April 7, 25) spanning 35 km perpendicular to the main channel. Each survey was flown at approximately 3 km altitude with a ~ 1 km swath width, achieving point densities of 4 - 10 points/m² and WSE accuracy of ~ 0.1 m resolution. Flight durations were up to 20 minutes per survey. These measurements provide critical validation and calibration data for satellite-based WSE observations in tidally influenced coastal environments, supporting improved understanding of estuarine hydrodynamics and remote sensing validation efforts. This dataset was collected under the Surface Water and Ocean Topography (SWOT) mission (https://noc.ac.uk/projects/swot-uk) and was funded by the UK Natural Environment Research Council and the UK Space Agency (NE/V009168/1).