Climate summary for the Arctic parks: Arctic Inventory and Monitoring Network

Sousanes, Pamela; Hill, Ken

Climate is one of the key vital signs being monitored as part of the National Park Service (NPS) Arctic Inventory and Monitoring Network (ARCN). Seventeen new climate stations were installed between 2011 and 2014 across the five Arctic parks to provide relevant and credible weather data that could be used to look at long and short term climate trends that influence every aspect of park ecosystems. The data from weather stations at Bettles, Kotzebue, and Nome, with observations dating back >50 years, are used to provide the climate context for the park units. Annual and seasonal climate statistics and trends from the long-term records are summarized (through the fall of 2016) along with the first few years of data from the park sites. Temperature trends across the region are non-monotonic with variability on seasonal, annual, and decadal scales primarily influenced by large-scale oceanic and atmospheric circulation patterns. Warm sea surface temperatures off the coast of Alaska in 1976 led to an abrupt upward shift in temperatures that was evident statewide, for the next few decades the temperatures were relatively stable, until recently. Over the past few years another uptick in temperatures has occurred with anomalously warm sea surface temperatures and air temperatures being observed over Alaska from 2014 through 2016. Meanwhile, sea ice continues to decrease with the influx of warm waters in northern latitudes, setting off a cascade of impacts that would be difficult to reverse. The temperature patterns at the new park stations track very well with the index sites, for example a warm winter in Bettles generally means a warm winter at the higher elevation mountain sites, however the absolute values differ. Mountain sites, as expected, are cooler in the summer and warmer in the winter due to persistent inversions. Coastal site temperatures depend on the presence or absence of sea ice to moderate temperatures and provide moisture availability. As we obtain more data we can start to understand the gradients between the coastal and interior sites and tease out the North Slope effect on these high-latitude parks. Precipitation is much more variable and difficult to measure at remote locations. Summer rainfall and snow depth is measured at the NPS stations, and in general, there seems to be more precipitation in the high mountains in summer and at mid-elevation coastal sites. Snowfall in the Arctic is relatively low, and what does fall is often redistributed by the wind. There is more persistent snow in areas of the parks within the boreal forest, where trees and vegetation can hold the snowpack. Mountain ridgelines and open tundra areas are often scoured free of snow, even in mid-winter. This was part of a larger effort to assess the current condition of park resources to promote the ongoing effort towards an integrated and strategic approach to resource planning and decision making. See more on the Natural Resource Condition Assessment Program at: https://www.nps.gov/orgs/1439/nrca.htm.

Climate summary for the Arctic parks: Arctic Inventory and Monitoring Network

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