wa.water.usgs.gov The USGS Benchmark Glacier Program: 50-Year Record of Glacier Mass Balance Reveals Shifting Climate in the Pacific Northwest and

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2007
• Subjects: Cascade Glacier; Meier; Pacific; glacier; glaciers; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.173.2093; http://quickplace.mtri.org/QuickPlace/bering/PageLibrary85256E4500721A82.nsf/h_Index/0446ECA09A35F7A08525745C006D5DA9/%24file/GlacierHandout_WA_AK.pdf/

began in 1957 as a result of research efforts during the International Geophysical Year (Meier and others, 1971). After 50 years of study, the USGS now has three glacier mass balance records that show the recent dramatic shrinkage of glaciers in three different climatic regions of the United States: South Cascade Glacier in the North Cascade Mountains of Washington, Figure 2. Retreat of South Cascade Glacier, Washington, during the last century. Wolverine Glacier near the southern coast of Alaska, and Gulkana Glacier in the interior of Alaska (Figure 1). These glaciers represent a large number of glaciers within each region. Glaciers respond to climate changes by thickening and advancing down-valley towards warmer lower altitudes or by thinning and retreating up-valley to higher altitudes. They average changes in climate over space and time and provide a picture of climate trends in remote mountainous regions. The most direct way to observe changes in a glacier is to measure its mass balance: the difference between the mass of snow that accumulates on the glacier, termed accumulation, and the mass of snow and ice that melts and runs off or is lost as water vapor, collectively termed ablation. If a glacier has a positive mass balance, its