Monitoring Arctic and boreal ecosystems through the assimilation of field-based studies, remote sensing, and modelling

Trends in mean annual temperature anomalies from the long-term mean (1950 to 2015) in Alaska; (b) plots of annual temperature anomalies and trends for all of Alaska overlain by annual anomalies of the Pacific Decadal Oscillation (PDO) Index (http://research.jisao.washington.edu/pdo/) as represented by a dashed line, and; (c) plots of anomalies and trends in Landscape Conservation Cooperatives (LCCs) Region (Pastick, 2018)

(Public domain.)

The following is a brief overview of focal areas of EROS’ research on Arctic and boreal landscapes in Alaska:

Permafrost characterization:

Permafrost – permanently frozen ground – is estimated to underly nearly a quarter of the northern circumpolar and is vulnerable to thaw with continued climate warming. Changes in permafrost distribution can impact ecological, hydrological and topographical conditions, thereby disrupting communities, infrastructure, and fish and wildlife populations. Permafrost is difficult to monitor and map, however, because it is a subsurface phenomenon that is typically covered by surface organic material (e.g. vegetation).  To address ecological and spatial complexities inherent when characterizing permafrost-affected soils, our team leverages state-of-the-art modelling tools and remote sensing data to extend geophysical surveys to the larger landscape. Our quantitative modeling approaches have enabled a new generation of permafrost maps and techniques needed by land resource managers and modelers to better understand Alaska’s changing landscape.

Projected near-surface (within 1 m) permafrost probabilities for Alaska, using downscaled climate forcing data from an average of five general circulation model outputs with an A1B emission scenario for the 21^st century (Pastick et al. 2015).

(Public domain.)

Deploying geophysical equipment in interior Alaska to assess the effect of wildfire on permafrost. Small electrical signals are injected into the ground through metal stakes connected to the orange cable in the foreground. The measured response is used to detect belowground permafrost conditions.

(Public domain.)

Land and surface-water dynamics:

Terrestrial and aquatic ecosystem modelling provides a means for documenting and understanding historical and potential ecosystem changes in the face of climate warming.  Our studies on land and surface waters range in scope from modelling and mapping of terrestrial biomass, which is a key biophysical parameter in the studies of Alaska's ecosystems, to the quantification of ecological, hydrological, and geomorphological change using remote sensing and process-based models. By incorporating field and geospatial data into modeling frameworks, we continue to investigate the interconnected responses in vegetation productivity, composition, surface-water dynamics and disturbances to climate warming.  Current work addresses the characterization and implications of earth-surface dynamics on permafrost-affected landscapes and communities, including thermokarst, lacustrine dynamics, wildfire, and erosion and deposition.

Time series imagery of the Ninglick River encroaching on Newtok, a village of 350 located in south western Alaska. (Credit: Neal J. Pastick)

(Public domain.)

Map of Alaska showing probability (%) of change occurrence from 1984 to 2015. Insets show fire boundaries from the Bureau of Land Management (BLM) Large Fire Database and Landsat 8 imagery (bottom right; 2016) north of Fairbanks, Alaska (Pastick et al. 2018)

(Public domain.)

Funding

This research has been funded by the U.S. Geological Survey Land Change Science, Biological Sequestration (LandCarbon), National Research, and Climate Land Use Research and Development Programs, as well as NASA’s Arctic-Boreal Vulnerability Experiment (ABoVE) and the Fish & Wildlife Service.