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The global mean surface temperature increased 0.85°C during the period 1880 – 2012. Some climate models predict an additional warming of up 2 to 4 ◦ C over the next 100 years for the primary breeding grounds for North American ducks. Such an increase has been predicted to reduce mid - continent breeding duck populations by >70%. Managing continental duck populations in the face of climate change requires understanding how waterfowl have responded to historical spatio - temporal climatic variation. However, such responses to climate may be obscured by how ducks respond to variation in land cover. We estimated effects of climate on settlement patterns of breeding ducks in the Prairie - Parkland Region (PPR), boreal...
Abstract (from http://onlinelibrary.wiley.com/doi/10.1111/gcb.12875/abstract): Permafrost thaw can alter the soil environment through changes in soil moisture, frequently resulting in soil saturation, a shift to anaerobic decomposition, and changes in the plant community. These changes, along with thawing of previously frozen organic material, can alter the form and magnitude of greenhouse gas production from permafrost ecosystems. We synthesized existing methane (CH 4) and carbon dioxide (CO 2) production measurements from anaerobic incubations of boreal and tundra soils from the geographic permafrost region to evaluate large-scale controls of anaerobic CO 2 and CH 4 production and compare the relative importance...
Abstract: P-band interferometric synthetic aperture radar (InSAR) data at 5 m resolution from Kahiltna Glacier, the largest glacier in the Alaska Range, Alaska, USA, show pronounced spatial variation in penetration depth, δ P. We obtained δ P by differencing X- and P-band digital elevation models. δ P varied significantly over the glacier, but it was possible to distinguish representative zones. In the accumulation area, δ P decreased with decreasing elevation from 18±3 m in the percolation zone to 10±4 m in the wet snow zone. In the central portion of the ablation area, a location free of debris and crevasses, we identified a zone of very high δ P (34±4 m) which decreased at lower elevations (23±3 m in bare ice...
Abstract (from http://www.sciencedirect.com/science/article/pii/S1873965215000110): The goal of this study was to assess the importance of the 2007 sea ice retreat for hydrologic conditions on the Alaskan North Slope, and how this may have influenced the outbreak of tundra fires in this region. This study concentrates on two years, 2007 and 1996, with different arctic sea ice conditions and tundra fire activity. The year of 2007 is characterized by a low summer sea ice extent (second lowest) and high tundra fire activity, while 1996 had high sea ice extent, and few tundra fires. Atmospheric lateral boundary forcing from the NCEP/NCAR Reanalysis drove the Weather Research and Forecast (WRF) model, along with varying...
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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The Jago, Okpilak, and Hulahula rivers in the Arctic are heavily glaciated waterways that are important for fish and wildlife as well as human activities including the provision of food, recreation, and, potentially, resource extraction on the coastal plain. If current glacial melting trends continue, most of the ice in these rivers will disappear in the next 50-100 years. Because of their importance to human and natural communities, it is critical to understand how these rivers and their surrounding environments will be affected by climate change and glacier loss. The overarching goal of this project was to research (1) the amount of river water, sediment, nutrients, and organic matter in the Jago, Okpilak, and...
Abstract: To test the effects of altered hydrology on organic soil decomposition, we investigated CO2 and CH4 production potential of rich-fen peat (mean surface pH = 6.3) collected from a field water table manipulation experiment including control, raised and lowered water table treatments. Mean anaerobic CO2 production potential at 10 cm depth (14.1 ± 0.9 μmol C g-1 d-1) was as high as aerobic CO2 production potential (10.6 ± 1.5 μmol C g-1 d-1), while CH4 production was low (mean of 7.8 ± 1.5 nmol C g-1 d-1). Denitrification enzyme activity indicated a very high denitrification potential (197 ± 23 μg N g-1 d-1), but net reduction suggested this was a relatively minor pathway for anaerobic CO2 production. Abundances...
Abstract (from: http://www.igsoc.org/journal/60/221/j13J176.html): The Randolph Glacier Inventory (RGI) is a globally complete collection of digital outlines of glaciers, excluding the ice sheets, developed to meet the needs of the Fifth Assessment of the Intergovernmental Panel on Climate Change for estimates of past and future mass balance. The RGI was created with limited resources in a short period. Priority was given to completeness of coverage, but a limited, uniform set of attributes is attached to each of the ~198 000 glaciers in its latest version, 3.2. Satellite imagery from 1999–2010 provided most of the outlines. Their total extent is estimated as 726 800 +/- 34 000 km2. The uncertainty, about +/-...
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Ducks and other waterfowl in the U.S. are valued and enjoyed by millions of birdwatchers, artists, photographers and citizens for their beauty and appeal. Waterfowl also provide game for hunters throughout the country and act as an important source of revenue for states and local communities. Loss of habitat and migration corridors due to land use changes and changes in climate threaten these birds, however more scientific information is needed to understand these processes. This project used available annual surveys of duck counts, along with data on the location and availability of ponds and temperature and precipitation patterns, to model where across the continental landscape waterfowl were present and if their...
Streamwater dissolved oxygen (DO) concentrations are driven by interacting physical and biotic parameters. Future DO depletion events in small, coastal salmon streams are therefore likely to be driven by changes in hydrology in addition to atmospheric warming. We measured DO, temperature, discharge and spawning salmon abundance in upstream (reference reach) and downstream salmon bearing reaches of four streams in southeast Alaska to determine how multiple physical and biotic factors interact to control streamwater DO. Stream temperature ranged from 5.1 to 15.8 °C and fell within the optimum range that is considered favorable for salmon physiology. Concentrations of DO ranged from 2.8 to 12.3 mg/L, with concentrations...
Abstract: Arctic tundra ecosystems have experienced unprecedented change associated with climate warming over recent decades. Across the Pan-Arctic, vegetation productivity and surface greenness have trended positively over the period of satellite observation. However, since 2011 these trends have slowed considerably, showing signs of browning in many regions. It is unclear what factors are driving this change and which regions/landforms will be most sensitive to future browning. Here we provide evidence linking decadal patterns in arctic greening and browning with regional climate change and local permafrost-driven landscape heterogeneity. We analyzed the spatial variability of decadal-scale trends in surface greenness...
Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/hyp.9934/abstract): Adaptation planning in Alaska, as in other snowy parts of the world, will require snow projections, yet snow is a challenging variable to measure, simulate and downscale. Here we describe the construction and evaluation of 771-m-resolution gridded historical and statistically downscaled projections of snow/rain partitioning for the state of Alaska at decadal temporal resolution. The method developed here uses observational data to describe the relationship between average monthly temperature and the fraction of wet days in that month receiving snow, the snow-day fraction. Regionally and seasonally specific equations were developed to...
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Rates of glacier loss in the northern Pacific coastal temperate rainforest (PCTR) are among the highest on Earth. These changes in glacier volume and extent will affect the flow and chemistry of coastal rivers, as well as the nearshore marine ecosystem of the Gulf of Alaska (GOA). Runoff from glaciers accounts for about half of the land-to-ocean movement of freshwater into the GOA, strongly influencing the freshwater and marine ecosystems along the coast. Runoff from glaciers, for example, significantly impacts the water temperature and clarity of aquatic habitats, which are important conditions for salmon reproduction. Moreover, runoff from glaciers along the GOA is an important factor in the structure of the...
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Ongoing climate change has the potential to negatively impact Alaska’s ecosystems and the critical services that they provide. These ecosystem services include supplying food and fiber for Alaskan communities, offering opportunities for recreational, cultural, and spiritual activities, and regulating temperature and water flow (runoff, flooding, etc.). Scientists build models to better understand processes and interactions in the natural environment and to use what we know to predict what will happen in the future, so that we can plan for it. Researchers from multiple institutions and disciplines developed an Integrated Ecosystem Model (IEM) for Alaska and Northwest Canada. The model helps forecast how climate...
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Ongoing and future climate change throughout Alaska has the potential to affect terrestrial ecosystems and the services that they provide to the people of Alaska and the nation. These services include the gathering of food and fiber by Alaskan communities, the importance of ecosystems to recreation, cultural, and spiritual activities of people in Alaska, and the way that land cover and vegetation in ecosystems affect temperature and water flow (runoff, flooding etc.) throughout the state. Assessments of the effects of climate change on these “ecosystem services” have been hindered by a lack of tools (e.g. computer models) capable of forecasting future landscapes in a changing climate while taking into account numerous...
Abstract (from http://www.sciencedirect.com/science/article/pii/S0168192316303446): Across a global network of eddy covariance flux towers, two relatively new open-path infrared gas analyzers (IRGAs), the IRGASON and the EC150, are increasingly used to measure net carbon dioxide (CO2) fluxes (Fc_OP). Differences in net CO2 fluxes derived from open- and closed-path IRGAs in general remain poorly constrained. In particular, the performance of the IRGASON and the EC150 for measuring Fc_OP has not been characterized yet. These IRGAs measure CO2 absorption, which is scaled with air temperature and pressure before converting it to instantaneous CO2 density. This sensor-internal conversion is based on a slow-response thermistor...
map background search result map search result map Development of the Alaska Integrated Ecosystem Model to Illustrate Future Landscape Change Understanding the Links between Climate and Waterbirds Across North America Understanding the Impacts of Permafrost Change: Providing Input into the Alaska Integrated Ecosystem Model The Impacts of Glacier Change on the Jago, Okpilak, and Hulahula Rivers in the Arctic Assessing Links between Glaciers and the Northern Pacific Coastal Temperate Rainforest Ecosystem The Impacts of Glacier Change on the Jago, Okpilak, and Hulahula Rivers in the Arctic Assessing Links between Glaciers and the Northern Pacific Coastal Temperate Rainforest Ecosystem Development of the Alaska Integrated Ecosystem Model to Illustrate Future Landscape Change Understanding the Impacts of Permafrost Change: Providing Input into the Alaska Integrated Ecosystem Model Understanding the Links between Climate and Waterbirds Across North America