EVALUATION OF PERMAFROST DEGRADATION IN THE NORTH SLOPE BOROUGH, ALASKA, USING ARCTICDEM AS TIME SERIES

Permafrost degradation in the Arctic is negatively effecting the environment, structures, and livelihoods of residents in Arctic areas. Melting of permafrost from increased global temperatures causes inconsistent land subsidence and compromises infrastructure, including buildings, roads, and energy pipelines. This study utilizes ArcticDEM data, created by the Polar Geospatial Center from DigitalGlobe, Inc. imagery, to calculate land subsidence in the north central section of the North Slope Borough in Alaska. DEM (digital elevation model) strips located around 70° N 156° W and created from imagery collected in 2010, 2011, 2012, 2015, 2016, and 2017 were utilized. The strips were calibrated to each other using unchanging elevation points and adjusting the DEMs by the difference in those areas. The DEM strips were then subtracted from each other to obtain maps of the amount of elevation change occurring in the study area over time. Areas of change due to fluvial and anthropogenic sources are identified and excluded from the change maps in order to focus on land subsidence from permafrost degradation. The remaining land subsidence is then associated with changes in the permafrost active layer and can be identified on the change maps. This type of time-series analysis improves our understanding of changes in permafrost over the past nine years and assists in mitigating the effects on future infrastructure as well as understanding the rapidly changing conditions in the Arctic. Future work will include seasonal analyses and expanded study areas.