Landcover change analysis for Assateague Island National Seashore following Hurricane Sandy

Assateague Island is a barrier island off the coast of the East Coast of the U.S that provides a number of unique habitats that support a wide variety of wildlife including several federally endangered species as well as offers numerous recreational activities for visitors. Resource managers tasked with developing effective resource strategies rely on updated land cover information to make effective decisions. In addition, with the frequency and intensity of extreme storm events expected to increase due to climate change, the assessment of storm damages is critically important if managers are to understand climate change impacts on their lands and improve management strategies to mitigate its effects. This study was performed to detect land cover change on Assateague Island as a result of Hurricane Sandy that struck the east coast in October 2012. Two types of Landsat data were utilized, Landsat 5 TM and the new Landsat 8 which carries the Operational Land Imager (OLI) sensor with increased radiometric resolution as well as several new bands. In addition to detecting land cover change several additional objectives were established including, evaluating the contribution of the new Landsat 8 bands to classification accuracy, comparing the performance of Landsat 8 for land cover classification with Landsat 5, and comparing object-based and pixel-based classification using moderate resolution data. Several single-date classifications were performed for each date of imagery using both the pixel-based and object-based approach. The Random Forest classifier was used for all classifications. Following the assessment of the single-date maps, univariate image differencing was used to conduct the change detection. This study found that the addition of the coastal blue band to the OLI sensor did not improve classification accuracy and there was also no statistically significant improvement in classification accuracy using Landsat 8 compared to Landsat 5 for this classification. Furthermore, there was no significant difference found between object-based and pixel-based classification. Change totals were estimated on Assateague Island following Hurricane Sandy and were found to be minimal, occurring predominately in the most active sections of the island in terms of land cover change.