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We mosaicked twelve LandSat-8 OLI satellite images taken during the summer of 2014, which were used in an object based image analysis (OBIA) to classify the landscape. We mapped seventeen of the most dominant geomorphic land cover classes on the Alaskan Coastal Plain (ACP): **value** | **class name** 1 | Coastal saline waters 2 | Large lakes 3 | Medium lakes 4 | Small lakes 5 | Ponds 6 | Rivers 7 | Nonpatterned Drained Thaw Lake Basins 8 | Coalescent low-center polygons 9 | Low-center polygons 10 | Flat-center polygons 11 | High-center polygons 12 | Drained slope 13 | Sandy barrens 14 | Sand dunes 15 | Riparian corridors 16 | Ice 17 | Urban (i.e. towns and roads)
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Abstract (from http://onlinelibrary.wiley.com/doi/10.1111/gcb.12757/abstract): The landscape of the Barrow Peninsula in northern Alaska is thought to have formed over centuries to millennia, and is now dominated by ice-wedge polygonal tundra that spans drained thaw-lake basins and interstitial tundra. In nearby tundra regions, studies have identified a rapid increase in thermokarst formation (i.e., pits) over recent decades in response to climate warming, facilitating changes in polygonal tundra geomorphology. We assessed the future impact of 100 years of tundra geomorphic change on peak growing season carbon exchange in response to: (i) landscape succession associated with the thaw-lake cycle; and (ii) low, moderate,...
Categories: Publication;
Types: Citation;
Tags: Alaska CASC,
Data Visualization & Tools,
Science Tools for Managers,
arctic,
carbon balance, All tags...
classification,
climate warming,
negative feedback,
polygonal tundra,
thaw-lake cycle,
thermokarst, Fewer tags
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Normalized difference vegetation index (NDVI) trend map was computed for the Alaskan Arctic Coastal Plain between 1999 and 2014. The decadal trend of each pixel was computed using 40-110 individual Landsat (TM, ETM+, OLI) satellite images acquired during July or August.
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Abstract (from http://www.ncbi.nlm.nih.gov/pubmed/26463267): Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic of fens, collapse-scar bogs, low shrub/scrub, and forests growing on elevated ice-rich permafrost soils. Thermokarst has affected the lowlands of the Tanana Flats in central Alaska for centuries, as thawing permafrost collapses forests that transition to wetlands. Located within the discontinuous permafrost zone, this region has significantly warmed over the past half-century, and much of these carbon-rich permafrost soils are now within ~0.5 °C of thawing. Increased permafrost thaw in lowland boreal forests in response to warming may have consequences for...
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