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Snow Cover Monitoring with MODIS Satellite Data in the Arctic Inventory and Monitoring Network, Alaska, 2000-2013 (Jun 30, 2014)

Snow cover was monitored in the five National Park Service (NPS) units of the Arctic Inventory and Monitoring Network (ARCN) from the fall of 2000 through the spring of 2013, using 500 m resolution daily data from the MODIS Terra satellite. The MODIS data were processed by the National Snow and Ice Data Center (NSIDC) and the Geographic Information Network for Alaska (GINA) at the University of Alaska Fairbanks to detect the first and last snow days of each season, and the start and end of the continuous snow season (CSS).

The median first snow day was in October over most of the low-elevation areas (<2000 feet, 620 m) of ARCN and mainly in September at higher elevations, except at elevations above 3000 feet (914 m) along the north side of the Brooks Range, where the first snow came in August. The start of the CSS was within 2 weeks of the first snow day over most of ARCN: late October in the lowlands (<1000 feet, 305 m) of western ARCN and early October elsewhere, except at elevations above 3000 feet (914 m), where the CSS began in September. In years with late snow cover establishment and cloudy fall weather, the date of first snow and the start of the CSS were not detected in some parts of ARCN before winter darkness and long terrain shadows obscured the ground. While this problem appears to not have substantially affected the long-term median values for first snow day and start of CSS, it prevented analysis of year-to-year variability in these two metrics.

The median length of the continuous snow season was 6 to 7 months in most lowland areas (below 1000 feet, 305 m), 7 to 8 months at most mid-elevations, and 8 to 9 months at most high elevations (above 4000 feet, 1219 m). The median last snow day and median last day of the CSS were less than a week apart in May over most of ARCN. Higher elevations in ARCN generally had later snow-off dates, though there was some interesting variability within this overall pattern. Snow usually disappeared ... [Read full article]

Warm Winter & Early Caribou Migration (May 13, 2014)

Western Alaska experienced an incredibly warm winter (December 2013 - March 2014), with temperatures 6-8 oF warmer than average. Warm and dry conditions continue into spring; coupled with low winter snowfall and rain events, these conditions led to many areas of the winter range of Western Arctic Herd having little or no snow. The herd calves in the Utukok Uplands, north of the Brooks Range, in early June. Right now, the herd’s spring migration to the calving grounds is much earlier (1-3 weeks) than other years the NPS has been tracking its timing.

What are pingos, tussocks, and ice-wedge polygons? (Dec 19, 2013)

Learn about pingos, tussocks, and ice-wedge polygons by using the Arctic Network's new interactive video website. Six videos explain what these fascinating features of the northern landscape are and how the function as part of the arctic ecosystem.

Vegetation Sampling in the Arctic Inventory and Monitoring Network, 2013 Progress Report (Nov 20, 2013)

The National Park Service, Arctic Inventory and Monitoring Network (ARCN) is nearing completion
of the initial round of sampling a system of permanent vegetation monitoring plots across 5 roadless
National Park Service (NPS) units in northern Alaska. Plots are located at “nodes”, which consist of
a base camp and approximately 20 plots accessible by foot or boat from the camp. Node locations are
chosen for accessibility via fixed-wing aircraft and proximity to a variety of ecosystems. Plot
locations are systematic along transects with a randomized start within stra ta based on major
landforms. The main sampling element is plant cover and height by the point intercept method; data
are recorded by species of vascular plants and by species or species-group of non-vascular plants.
Additional data elements include tree diameters and a list of all vascular species on a fixed-area plot,
and a soil and site description.

In 2013 we sampled 141 plots at 7 nodes. The total for the project is now 442 plots at 23 nodes
sampled mainly in 2011-13. We anticipate sampling approximately 45 more plots at 2 nodes in 2014,
at which point the first round of sampling will be considered complete. However, sampling of up to 5
additional nodes in the next several years is possible if data gaps are identified.

Coverage of the major ecological gradients by the plots was generally satisfactory. The distribution
of plots by elevation shows some bias toward lower elevations. This is due to the fact that our
landing sites (mainly lakes and river gravel bars) are concentrated a low elevatio ns, and highelevation areas are largely unvegetated and difficult to access. Ecotypes identified on an existing
ARCN-wide map are generally well represented, with deficiencies noted in the coverage of alpine
barren areas and tall shrub communities. For reasons of access efficiency and safety, these types are
likely to remain under-sampled.

Digital Surficial Geologic Map of Gates of the Arctic National Park and Preserve Published (Sep 18, 2013)

The Geologic Resources Inventory (GRI) Team is pleased to announce the completion and availability of digital geologic map coverage for Gates of the Arctic National Park and Preserve (GAAR). Providing parks with digital geologic maps meets the geologic inventory goal defined and funded by the NPS Inventory and Monitoring Program. This map is provided in full GIS coverage and can be found at:

The GRI map

Digital Surficial Geologic Map of Gates of the Arctic National Park and Preserve, Alaska (GRI MapCode GSUR)

The GRI GAAR IRMA project record

Potential effects of warming climate on visitor use in three Alaskan national parks (Sep 6, 2013)

Alaska’s national parks draw millions of people annually to enjoy wildlife, breathtaking scenery, and recreational adventure. Visitor use is highly seasonal and occurs primarily during the summer months when temperatures are warm and daylight is long. Climate is an important consideration when planning a trip to Alaska’snational parks because of the great distances and associatedcosts of travel for many visitors. As a result of projected climatewarming, peak visitor season of use in Alaska’s national parksmay expand. To examine the potential effects of warming climate on park visitor season of use, we used regression analyses to quantify the relationship between historical (1980–2009) visitoruse and monthly temperatures for three Alaskan national parks and identi? ed the monthly mean temperatures at which the peakvisitor season of use occurred in each park. We compared thesecontemporary temperatures with projected future average monthlymean temperatures for 2040–2049 and 2090–2099 to providecontext for how visitation might be affected by warming climate.Based on historical relationships among temperature, visitor use, and increased temperatures associated with climate change, ouranalysis suggests that peak season of visitor use could expand into May and September depending on the park, the climate scenario,and the time period. As a consequence of a warming climate, planning by the National Park Service and other stakeholders mayneed to consider this transition in temperatures and the potentialfor an extended peak season of visitor use, along with otherclimate-related changes (e.g., extreme weather), climate-inducedenvironmental changes, and shifts in recreational opportunities that will likely accompany climate change.

New Approach to Dall’s Sheep Monitoring Better, Cheaper (Jul 8, 2013)

FAIRBANKS, AK— Scientists with the National Park Service have developed new methods for monitoring Dall’s sheep in Alaska that are providing better information while reducing costs by as much as 80% over existing survey approaches.

The methods and survey results are described in an article published in the current issue of the Journal of Wildlife Management (Schmidt and Rattenbury 2013) as well as in an article published in the same journal last year (Schmidt et al. 2012).

The majority of sheep habitat in seven national park units, including Denali, Gates of the Arctic, Noatak, Kobuk Valley, Cape Krusenstern, Wrangell-St. Elias, and Lake Clark, was surveyed in 2010-12 using the new technique, and the estimated population for the surveyed park units is currently 27,000-28,000 individuals—similar to the number present in the early 1980s when many of the park units were formed.

“Designing a monitoring program that provides accurate results in these large, remote areas is a challenge,” said Kumi Rattenbury, Ecologist with the National Park Service in Fairbanks. “We’re excited about this new approach because it means we can do a better job tracking the status of this iconic species over a huge area.

”The approach uses aerial distance sampling techniques to estimate overall population size as well as the composition (lambs, ewes, full curl rams, and < full-curl rams) of each population. It was first implemented by the National Park Service in Gates of the Arctic National Park and Preserve in 2009 where park-wide surveys were completed for the first time in nearly 30 years.

“This is one of the few ways to get a rigorous estimate of both abundance and composition from the same survey,” said Joshua Schmidt, National Park Service Biometrician and lead author on the two articles describing the new methods. “The higher quality data and lower costs will allow us to more consistently monitor populations and improve sheep ... [Read full article]

Reducing Effort While Improving Inference: Estimating Dall’s Sheep Abundance and Composition in Small Areas. (Jun 26, 2013)

National Park Service wildlife biologist Kumi Rattenbury and Biometrician Josh Schmidt recently published a new article in the Journal of Wildlife Management titled 'Reducing Effort While Improving Inference: Estimating Dall’s Sheep Abundance and Composition in Small Areas'.

Arctic Network Summer 2013 Newsletter (Jun 14, 2013)

If you want to know how and where the NPS Arctic Network monitor shallow lakes, rivers and streams, and coastal lagoons or what field work we are doing this summer, then please check out our Summer 2013 newsletter!

Alaskan Arctic National Parks Landscape Viewer (Apr 22, 2013)

The National Park Service Arctic Network Inventory and monitoring program announces a new rich internet map service. The "Alaskan National Parks Landscape Viewer" is a new interactive Internet feature that provides a birds-eye view of 5 National Parks in northern Alaska. It features satellite images and aerial photographs draped over topography to simulate a 3D view from above. Users can fly to points of interest by selecting them from a menu that also provides a written narrative. They can also explore on their own with interactive pan, zoom, and tilt. The viewer utilizes open source software developed by the Open Web Globe project, based at the Institute of Geomatics Engineering at the University of Applied Sciences and Arts Northwestern Switzerland. Anyone with a WebGL-enabled browser, such as Google Chrome or Mozilla Firefox, and a reasonably fast Internet connection can use it. Access the viewer at

Last Updated: June 30, 2014 Contact Webmaster