A DEMONSTRATION OF LIDAR METRICS ANALYSIS AND BARRIER ISLAND MORPHODYNAMIC CLASSIFICATION, NORTH ASSATEAGUE ISLAND, MARYLAND

A multi-temporal airborne lidar change analysis of north Assateague Island, Maryland has been undertaken to demonstrate the calculation of lidar metrics that condense barrier island morphology and morphological change into attributed linear features that may be used to analyze trends in coastal evolution. These methods are also of significant practical value, because lidar metric analysis reduces large volumes of point elevations into linear features attributed with essential morphological variables that are ideally suited for inclusion in Geographic Information Systems.

Lidar change metrics calculated for north Assateague Island were applied in a pattern recognition procedure that yielded a morphodynamic classification for a recent annual cycle. This analysis revealed the relative magnitude and fine scale alongshore variation in the importance of coastal changes over the study area during a defined time period between two airborne lidar surveys. More generally, this analysis demonstrates the value of lidar metrics in both examining large lidar data sets for coherent trends, and in building hypotheses on processes of barrier island evolution.

Recent advances in airborne lidar instrumentation have the potential to enhance multi-temporal lidar change analysis of barrier islands by enabling the simultaneous surveying of "bald earth" topography and adjacent shallow bathymetry. The NASA Experimental Advanced Airborne Research Lidar (EAARL) provides cross-environment surveys by the use of a scanning pulsed blue-green wavelength laser combined with a receiver that records the entire waveform of each reflected laser pulse. In addition to integrated topographic/bathymetric surveying, the NASA EAARL enables discrimination of ground surface elevations in the presence of some vegetation, and thereby removes a significant potential source of error in lidar-based analyses of geomorphic change.