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Lidar
In a cooperative research program, the U.S. Geological Survey, NASA and the U.S. Army Corps of Engineers have been mapping the coastlines of the United States using airborne laser altimeters, or lidar (light detection and ranging). The laser altimeter scans a several hundred meter wide swath of the earth's surface acquiring an estimate of ground elevation every few square meters. Baseline surveys conducted during periods of calm weather are compared to surveys collected following extreme storm events in order to quantify the resulting coastal change. (Examples of lidar-measured coastal change: a Nor'easter on Assateague island and Hurricane Katrina's impact on Dauphin Island.)
Two instruments are currently used for the majority of our surveying efforts: NASA's EAARL (Figures 1 and 2) and the U.S. Army Corps' CHARTS. These instruments survey hundreds of kilometers of coast in a single day with data densities that cannot be achieved with traditional survey technologies. Specifications for the lidar instruments can be found on the individual websites for NASA's EAARL and U.S. Army Corps' CHARTS. Airborne scanning laser surveys are providing unprecedented data to investigate the magnitude and causes of coastal changes that occur during severe storms.
For additional information on the EAARL instrument and processing of EAARL data, please refer to the website for the USGS Integrated Remote Sensing and Modeling Group.
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U.S. Department of the Interior |
U.S. Geological Survey
