Remote Sensing of the Arctic Coast of Alaska Using Airborne Lidar Data

As part of a U.S. Geological Survey assessment of coastal change hazards, over 11,000 km² of airborne lidar elevation data were collected along the Arctic coast of Alaska between 2009 and 2012. Data coverage includes the barrier islands and mainland coast between Icy Cape and the U.S.-Canadian border, from the shoreline to ~1.5 km inland. Data coverage extends further inland to around 3 km on the Barrow Peninsula and along the coast of the Teshekpuk Lake Special Area (TLSA) where coastal erosion rates are among the highest in the world (> 18 m/yr). Nominal point density is 1.5 m and vertical accuracy is better than 30 cm. Data were not collected over most river deltas or large embayments, with the exception of Admiralty Bay, Smith Bay (Ikpikpik Delta), Kogru River, and the Fish Creek portion of Colville River Delta. The primary use of the lidar data is to establish a modern shoreline position to be used for change analyses with historical shoreline positions. However, the lidar DEM provides a wealth of topographic and intensity data that can be used for morphological mapping of the remote arctic coast. This is one of the first comprehensive lidar datasets collected in a continuous permafrost environment. Many periglacial landscape features, such as patterned ground, ice-wedge polygons, and thermokarst lakes and former lake basins (recent and relict) are discernible in the dataset. Traditional coastal landscape features including shoreline position, beach width, slope, and bluff height and morphology are also distinct. Here we present an overview of the dataset and an assessment of methodologies developed for characterizing and classifying a variety of landscape features including overall complexity, geometry and morphology of polygonal tundra (polygon spacing, high center vs. low center), coastal bluff morphology (vertical or overhanging, convex vs. concave), drainage patterns and hydrologic connectivity. We also investigate the dataset to estimate offsets between ellipsoid and sea-level elevations, which is necessary for evaluating the vulnerability of the coast to inundation associated with storm surge, sea-level rise, oil spills and other marine-associated hazards.