Skip to main content
Advanced Search

Filters: Tags: Alaska CASC (X)

176 results (211ms)   

Filters
Date Range
Extensions
Types
Contacts
Categories
Tag Types
Tag Schemes
View Results as: JSON ATOM CSV
thumbnail
Birds are appreciated and enjoyed by thousands of people and also play important roles in the ecosystem as predators, prey, and pollinators. Alaska provides important breeding ground for hundreds of migratory bird species that travel thousands of miles in their annual migrations between breeding and wintering spots. Understanding how climate and land use changes affect migratory bird populations is crucial; however this information is also very difficult to collect. Migration routes expose birds to a wide range of landscapes and habitats, which are often experiencing varying degrees of climate and land use change (e.g. warmer temperatures or increased housing developments). Moreover, climate change in the future...
thumbnail
This collection includes several datasets related to the fraction of precipitation days that are snowy (vs. rainy) and the amount of precipitation that likely falls as snow across Alaska. Both historical and future projections are included. Files include: Climatological summaries of downscaled historical and projected decadal average monthly snowfall equivalent ("SWE", in millimeters), the ratio of snowfall equivalent to precipitation, and future change in snowfall for October to March at 771 meter spatial resolution across the state of Alaska. Historical downscaled estimates of decadal average monthly snow-day fraction ("fs", units = percent probability from 1 to 100) for each month of the decades from 1900 through...
Abstract (from http://www.nature.com/nature/journal/v521/n7551/full/nature14238.html): Over 20% of Earth’s terrestrial surface is underlain by permafrost with vast stores of carbon that, once thawed, may represent the largest future transfer of carbon from the biosphere to the atmosphere1. This process is largely dependent on microbial responses, but we know little about microbial activity in intact, let alone in thawing, permafrost. Molecular approaches have recently revealed the identities and functional gene composition of microorganisms in some permafrost soils2, 3, 4 and a rapid shift in functional gene composition during short-term thaw experiments3. However, the fate of permafrost carbon depends on climatic,...
thumbnail
These files include a derived 50 meter spatial resolution Compound Topographic (or Wetness) Index ([CTI or TWI](https://en.wikipedia.org/wiki/Topographic_Wetness_Index)) and Flow Accumulation (as represented by specific catchment area, SCA) calculated from a continuous, transboundary DEM developed across the Alaska perhumid coastal temperate rainforest (AKPCTR). The extent of this dataset includes all of the Alaska and Canada watersheds that discharge into southeast Alaska coastal waters, which covers essentially the northern half of the full PCTR. The transboundary DEM used to calculate the CTI can be here: [link](http://ckan.snap.uaf.edu/dataset/a-continuous-transboundary-50-meter-dem-for-the-alaska-perhumid-coastal-temperate-rainforest-ak06b59)...
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,...
thumbnail
AKPCTR_DEM is a 50-meter resolution, bare-earth digital elevation model (DEM) in raster (geotiff) format. The perhumid (wettest) region of the North American coastal temperate rainforest (PCTR) extends along the coast of British Columbia and southeast Alaska between approximately 50.57 and 59.6 degrees north latitude.The extent of this dataset includes all of the Alaska and Canada watersheds that discharge into southeast Alaska coastal waters, which covers essentially the northern half of the PCTR. **General Methods:** Using Desktop ArcGIS version 10.3.1, the following three elevation datasets were combined to create a continuous DEM for the Alaska perhumid coastal temperate rainforest (AKPCTR) watersheds: 1)...
thumbnail
Permafrost – the thick layer of permanently frozen soil found in Arctic regions – has been thawing rapidly over the past century due to climate change. When permafrost thaws unevenly, it produces thermokarst landscapes, irregular surfaces of small hills interspersed with hollows. The processes that produce thermokarst can lead to significant changes within the surrounding ecosystems, altering water quality, vegetation, and water, carbon, and nutrient storage and flows. These changes can have substantial implications for fish and wildlife populations and disrupt rural communities and infrastructure. The goal of this project was to better understand the extent of thermokarst processes and the rate at which they...
thumbnail
Retreating glaciers are an iconic image of climate change;yet not all glaciers in Alaska are actively retreating, and a few glaciers are even advancing. While this contrasting behavior can be misleading for the casual observer, variable responses between glaciers in a changing climate are expected. Glaciers act as conveyor belts that transport snow and ice from high elevations, where it does not melt, down to low elevations, where it does melt. A change in climate can impact the amount of snow and ice that accumulates (accumulation), the way snow and ice melt (ablation), or the conveyor belt (ice dynamics). While these impacts vary with elevation and glacier shape, glacier changes have major implications for downstream...
thumbnail
Major floods in Southeast Alaska and Hawaiʻi that potentially threaten life, property, and culturally significant resources and ecosystems are caused by mechanisms related to intense precipitation for both locations as well as snow melt-based processes for Alaska. Small, high-gradient, and heavily vegetated watersheds with direct contribution to the ocean are common in both locations. To understand how climate change may affect flooding in these regions, an analysis of the underlying mechanisms that cause flooding is needed. The scope of this study includes an analysis of annual peak-streamflow records from long-term streamgages in Southeast Alaska and Hawaiʻi to determine whether the main flood-producing mechanisms...
thumbnail
Alaska’s land, water, plants, wildlife, and seasons are undergoing a great upheaval, and its people, especially the communities living in remote villages are directly and severely impacted by these widespread environmental changes. These changes are not only widespread but also often so rapid that we cannot possibly have enough scientists and professionals on the ground to detect and predict these changes before their effects are obvious. Especially environmental changes occurring in and around the remote communities in Alaska are directly affecting the subsistence resources and practices, thus have the most impact on the socio-economic conditions of these communities. In order to detect, monitor, and forecast these...
thumbnail
Stream discharge and temperature patterns are being altered by climate change, but documenting these changes on the community level is challenging without community partners trained in suitable data collection techniques. The USGS Juneau Field Office is collaborating with the Yakutat Tlingit Tribe (YTT), the Southeast Alaska Tribal Ocean Research (SEATOR) network, and the Southeast Alaska Watershed Coalition (SAWC) to integrate stream discharge and stream temperature monitoring into ongoing Tribal-led climate adaptation, water quality, and species management projects. Stream discharge and temperature data is limited in Southeast Alaska and improving the spatial coverage of this data would be mutually beneficial...
thumbnail
Caribou populations in Alaska are important to both resident and visiting hunters and provide a large source of income for commercial operators and local communities who provide services to these hunters. Caribou have also provided a traditional staple food source for native Alaskan communities. Moreover, caribou are important prey for wolves and bears and their health and population size impact the entire food web in the region. The 2013 Arctic Report Card from NOAA reported declining populations of caribou throughout Alaska. Several possible mechanisms may be responsible for the declines, including changes in climate. This project aimed to form a research consortium to bring together scientists and partners...
thumbnail
In Alaska, extreme climate events such as very warm days, very cold days, and intense storms can have a range of impacts, from damaging infrastructure to disrupting the tourism economy. For example, in 2013, a colder than normal spring led to late ice break-up and rapid thaw, causing massive flooding along the Yukon River that displaced roughly 500 residents in a single town. Meanwhile, in Denali, cold May temperatures delayed openings for some tourist-related businesses. Previous work has identified which atmospheric circulation patterns are associated with extreme events, information which can help refine forecasts and downscale future climate projections. The goal of this project is to test whether these patterns...
thumbnail
The eulachon is a small fish that is both highly nutritious and culturally significant to the Chilkat and Chilkoot peoples of the Tlingit Nation in Southeast Alaska, for whom it is a traditional food. Tribal members are increasingly concerned about how climate change might stress the health and abundance of eulachon populations, which are already perceived as being low. In order to successfully manage these fisheries in light of climate change, tribal communities need information about how euchalon are vulnerable and which management strategies will help the species adapt. For this project, researchers used climate projections, monitoring data, and traditional ecological knowledge to assess the climate change vulnerability...
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.
Abstract (from RMetS): Snowfall and snow season length across Alaska control the surface hydrology and underlying soil properties and also influence near‐surface air temperature by changing the energy balance. Current projections of warming suggest that considerable change will occur to key snow parameters, possibly contributing to extensive infrastructure damage from thawing permafrost, an increased frequency of rain‐on‐snow events and reduced soil recharge in the spring due to shallow end‐of‐winter snowpack. This study investigates projected changes to mean annual snowfall, dates of snow onset and snowmelt and extreme snowfall for Alaska, using dynamically downscaled reanalysis and climate model simulations. These...
Abstract (from http://www.sciencedirect.com/science/article/pii/S0309170815002444): The northern portion of the Pacific coastal temperate rainforest (PCTR) is one of the least anthropogenically modified regions on earth and remains in many respects a frontier area to science. Rivers crossing the northern PCTR, which is also an international boundary region between British Columbia, Canada and Alaska, USA, deliver large freshwater and biogeochemical fluxes to the Gulf of Alaska and establish linkages between coastal and continental ecosystems. We evaluate interannual flow variability in three transboundary PCTR watersheds in response to El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Arctic...
Abstract (from http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0132652): Climate warming is likely to cause both indirect and direct impacts on the biophysical properties of stream ecosystems especially in regions that support societally important fish species such as Pacific salmon. We studied the seasonal variability and interaction between stream temperature and DO in a low-gradient, forested stream and a glacial-fed stream in coastal southeast Alaska to assess how these key physical parameters impact freshwater habitat quality for salmon. We also use multiple regression analysis to evaluate how discharge and air temperature influence the seasonal patterns in stream temperature and DO. Mean daily...
map background search result map search result map Linking Climate, Vegetation, and Caribou Dynamics Across the Alaska Region Monitoring Thermokarst on the Landscapes of Northern Alaska Identifying Climate Vulnerabilities and Prioritizing Adaptation Strategies for Eulachon Populations in Southeast Alaska Developing a Coordinated, Multi-Region Effort to Understand the Effects of Climate Change on Migratory Birds Compound Topographic Index and Specific Catchment Area for the Alaska Perhumid Coastal Temperate Rainforest A Continuous, Transboundary, 50-meter DEM for the Alaska Perhumid Coastal Temperate Rainforest (AKPCTR_DEM) The Arctic in the Classroom: Study of Landscape Change in Remote Communities of Alaska: A K-12 Citizen Science Initiative toward Sustained Arctic Observations Collection: Historical and Projected Estimates of Snow Fraction and and the Amount of Precipitation that Likely Falls as Snow Across Alaska Characterizing Variability in the Drivers of Extreme Climate Events in Alaska Assessing the Vulnerability of Alaska’s Glaciers in a Changing Climate Characterization of Flood-Producing Mechanisms in Watersheds with a High-Elevation Area in Southeast Alaska and Hawaiʻi Integrating Stream Discharge and Temperature Monitoring for Tribal Partners in Southeast Alaska Identifying Climate Vulnerabilities and Prioritizing Adaptation Strategies for Eulachon Populations in Southeast Alaska Integrating Stream Discharge and Temperature Monitoring for Tribal Partners in Southeast Alaska Compound Topographic Index and Specific Catchment Area for the Alaska Perhumid Coastal Temperate Rainforest Monitoring Thermokarst on the Landscapes of Northern Alaska A Continuous, Transboundary, 50-meter DEM for the Alaska Perhumid Coastal Temperate Rainforest (AKPCTR_DEM) The Arctic in the Classroom: Study of Landscape Change in Remote Communities of Alaska: A K-12 Citizen Science Initiative toward Sustained Arctic Observations Characterizing Variability in the Drivers of Extreme Climate Events in Alaska Assessing the Vulnerability of Alaska’s Glaciers in a Changing Climate Characterization of Flood-Producing Mechanisms in Watersheds with a High-Elevation Area in Southeast Alaska and Hawaiʻi Linking Climate, Vegetation, and Caribou Dynamics Across the Alaska Region Developing a Coordinated, Multi-Region Effort to Understand the Effects of Climate Change on Migratory Birds Collection: Historical and Projected Estimates of Snow Fraction and and the Amount of Precipitation that Likely Falls as Snow Across Alaska