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The CA Academy of Science and Point Blue Conservation Science conducted a systematic analysis of uncertainty in modeling the future distributions of ~50 California endemic plant species and ~50 California land birds, explicitly partitioning among 5 alternative sources of variation and testing for their respective contributions to overall variation among modeled outcomes. They mapped the uncertainty from identified sources, which can guide decisions about monitoring, restoration, acquisition, infrastructure, etc., in relation to climate change.
The agro-hydrologic VegET (VegetationEvapotranspiration) model uses a water balance approach to simulate daily soil moisture (SM), actual evapotranspiration (ETa), and runoff (R). We enhanced the model to include snow accumulation and melt processes along with the separation of runoff into surface runoff and deep drainage and implemented the code using cloud technology. This publication is providing the supporting data for the updated methods and provides evaluation results for the United States and the Greater Horn of Africa.
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NWFP-20 - Northwest Forest Plan Effectiveness Monitoring (20-Year Report)Estimated completion June 2015This project is a continuation of research completed for the 15-year Report for NWFP Effectiveness Monitoring. We are continuing to develop and refine modeling techniques and data, to provide improved multi-date GNN maps of forest vegetation and older forest. Key improvements to GNN modeling to be implemented in this project are: (1) addition of more inventory plots, with yearly matching of plots to LandTrendr imagery for model development; (2) incorporation of measures of disturbance history, derived from LandTrendr algorithms, as spatial predictors; (3) improved GNN outlier analysis using TimeSync; and (4) additional...
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A combination of remote sensing and ecosystem modeling is used to examine the trends in NEP and net ecosystem carbon balance (NECB) in this region over the 1985 - 2007 period, with particular attention to land ownership since management now differs widely between public and private forestland. In the late 1980s, forestland in both ownership classes was subject to high rates of harvesting, and consequently the land was a carbon source (i.e. had a negative NECB). After the policy driven reduction in the harvest level, public forestland became a large carbon sink driven in part by increasing NEP whereas private forestland was close to carbon neutral.
Basal Temperature of Snow (BTS) measurements were used as the primary inputs to a high resolution (30 x 30 m grid cells) empirical-statistical regional permafrost probability model for the southern and central Yukon, and northernmost British Columbia (59° - 65°N). Data from seven individual study areas distributed across the region were combined using a blended distance decay technique, with an eighth area used for validation. The model predictions are reasonably consistent with previous permafrost maps for the area with some notable differences and a much higher level of detail. The modelling gives an overall permafrost probability of 52%. North of 62°N, permafrost becomes more extensive in the lowland areas whereas...
Much of northern North America (more than 6 million square kilometers) is characterized by the presence of permafrost (soils or rocks that remain frozen for at least two consecutive years). This permafrost region contains approximately 25% of the world's total soil organic carbon, a massive pool of carbon that is vulnerable to release to the atmosphere as carbon dioxide in response to an already detectable polar warming. The soils of the permafrost region of North America contain 213 billion tons of organic carbon, approximately 61% of the carbon in all soils of North America. The soils of the permafrost region of North America are currently a net sink of approximately 11 million tons of carbon per year. The soils...
The article describes some observations on the rise of permafrost temperatures in Alaska and Russia as of 2010. Alaska has experienced significant warming during the last two decades. In northern Russia, permafrost temperature rose by 1 to 2;° during the last three and a half decades. The similarity between Alaska and Russia is the significant warming during cold permafrost than in warm permafrost. (Copyright applies to all Abstracts.)
Air and surface temperatures were measured for one year at five sites with different permafrost conditions near Mayo, Yukon Territory, to examine the behaviour of freezing and thawing n-factors and the relations between air and surface temperatures. During the freezing season, surface temperatures were lower where the snow cover was thin. Where snow covers were similar, surface temperatures were lower where permafrost was present. The freezing n-factor is controlled primarily by snow, but also by subsurface thermal conditions. During the thawing season, surface temperatures were higher where the near-surface thermal diffusivity allowed for rapid descent of the frost table. The thawing n-factor is primarily controlled...
The Geological Survey of Canada (GSC), in collaboration with other government partners, has been developing and maintaining a network of active-layer and permafrost thermal monitoring sites which contribute to the Canadian Permafrost Monitoring Network and the Global Terrestrial Network for Permafrost. Recent results from the thermal monitoring sites maintained by the GSC and other federal government agencies are presented. These results indicate that the response of permafrost temperature to recent climate change and variability varies across the Canadian permafrost region. Warming of shallow permafrost temperatures of between 0.3 and 0.6°C per decade has occurred since the mid- to late 1980s in the central and...
The boundary between forest and tundra in mountainous areas, alpine treeline, is expected to advance as climate warming continues and change is likely to be pronounced in northern latitudes. I studied the white spruce ( Picea glauca (Moench) Voss) treeline in the Kluane region of southwest Yukon, Canada, with the objectives of: (i) characterizing its responses to past climate change, and (ii) assessing the influence of different environmental variables on spruce growth and treeline dynamics. Four investigations were conducted, each employing fundamentally different methodologies and occupying distinct levels within a hierarchical, scale-based, analytical framework. At the landscape scale, I mapped spruce distribution...
Thermokarst is developing in the boreal forests of Alaska where ice-rich discontinuous permafrost is thawing. Thawing destroys the physical foundation (ice-rich soil) on which boreal forest ecosystems rest causing dramatic changes in the ecosystem. Impacts on the forest depend primarily on the type and amount of ice present in the permafrost and on drainage conditions. At sites generally underlain by ice-rich permafrost, forest ecosystems can be completely destroyed. In the Mentasta Pass area, wet sedge meadows, bogs, thermokarst ponds, and lakes are replacing forests. An upland thermokarst site on the University of Alaska Campus consists of polygonal patterns of troughs and pits caused by thawing ice-wedge polygons....
Climate models and studies indicate that the changes in the northern latitudes will be serious and accelerated. Climate warming may impact structures in the northern latitudes through permafrost settlement affecting the performance of infrastructure and increasing costs for maintenance. The material presented is organized in three main chapters. Chapter 1 describes the motivation for the research. Chapter 2 addresses the permafrost settlement hazard in Alaska. I developed the Permafrost Settlement Hazard Index, which considered anticipated climate warming and ecological characteristics which regulate permafrost settlement. I found that the discontinuous permafrost region is at more risk due to permafrost settlement...
Understanding the role of permafrost in controlling groundwater flow paths and fluxes is central in studies aimed at assessing potential climate change impacts on vegetation, species habitat, biogeochemical cycling, and biodiversity. Recent field studies in interior Alaska show evidence of hydrologic changes hypothesized to result from permafrost degradation. This study assesses the hydrologic control exerted by permafrost, elucidates modes of regional groundwater flow for various spatial permafrost patterns, and evaluates potential hydrologic consequences of permafrost degradation. The Yukon Flats Basin (YFB), a large (118,340 km super(2)) subbasin within the Yukon River Basin, provides the basis for this investigation....
Over the past 50 years, Alaska has experienced a warming climate with longer growing seasons, increased potential evapotranspiration, and permafrost warming. Research from the Seward Peninsula and Kenai Peninsula has demonstrated a substantial landscape-level trend in the reduction of surface water and number of closed-basin ponds. We investigated whether this drying trend occurred at nine other regions throughout Alaska. One study region was from the Arctic Coastal Plain where deep permafrost occurs continuously across the landscape. The other eight study regions were from the boreal forest regions where discontinuous permafrost occurs. Mean annual precipitation across the study regions ranged from 100 to over...
map background search result map search result map Landscape Ecology, Modeling, Mapping & Analysis (LEMMA) Project Links Forest net ecosystem production for the Pacific Northwest, USA (gC/m2yr) Forest net ecosystem production for the Pacific Northwest, USA (gC/m2yr) Landscape Ecology, Modeling, Mapping & Analysis (LEMMA) Project Links