Glacier monitoring in the Central Alaska Network: Protocol narrative, version 1.0

Loso, Michael

doi:10.36967/2308209

Two of the three national parks that comprise the National Park Service Inventory & Monitoring Program’s Central Alaska Network (CAKN) are covered by large quantities of glacier ice. Wrangell-St. Elias National Park and Preserve has 3,121 glaciers and Denali National Park and Preserve has 881. These glaciers cover significant portions of the parks and exert substantial influence over the surrounding landscapes with impacts on weather, vegetation, animal migration, river flow, aquatic life, and even downstream marine ecosystems. They also provide a significant attraction—and hazard—for visitors. These glaciers are changing rapidly, primarily due to the influence of warming air temperatures. The impacts of glaciers on park resources and park visitors are not only important, but quickly evolving, with important consequences for park management. For all these reasons, the Central Alaska Network has identified glaciers as one of the vital signs that should undergo long-term monitoring. This document describes the protocol for conducting that monitoring program. Glacier monitoring in the CAKN parks began in 1991 with measurements of mass balance (snow accumulation and melt) and surface elevation at one site on Denali’s Kahiltna Glacier. The monitoring has evolved since that time to include mass balance measurements on a second large glacier (Kennicott Glacier) in Wrangell-St. Elias. Those two glaciers are highly visited, compared to most other glaciers in the parks, and are relatively accessible for monitoring purposes. The objectives of these measurements are to document seasonal and interannual changes in the primary climatic forces that control glacier change: snow accumulation and melt. Combined with periodic remeasurements of the glacier boundaries and surface elevations, the protocol records mass balances of these two glaciers with both glaciological and geodetic methods, allowing analysis of total mass balance with accompanying understanding of the climatic forces behind it. The glacier monitoring protocol also calls for the use of increasingly available remote sensing techniques to document changes in glacier areas, surface elevations, and surface velocities for a broad collection of park glaciers. Outside the scope of the CAKN protocol, boundaries of all park glaciers have been digitized twice over the last decade, and this protocol calls for continuation of that decadal inventory using whatever remote sensing data and techniques are most applicable at each decadal time step. A subset of the largest park glaciers is also slated for measurement of surface elevations every 4-6 years, continuing the measurements made by Operation IceBridge since the mid-1990s.

Glacier monitoring in the Central Alaska Network: Protocol narrative, version 1.0

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