Alaska Science Center

 

Geodetic Data for USGS Benchmark Glaciers: Orthophotos, Digital Elevation Models, and Glacier Boundaries

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to complement data collected by the Juneau Icefield Research Program (JIRP; Pelto and others, 2013). Direct field measurements are combined with weather data and imagery analyses to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). The analysis framework (O'Neel, 2019, van Beusekom and others, 2010) is identical at each glacier to enable cross-comparison between output time series. Vocabulary used follows Cogley and others (2011) Glossary of Glacier Mass Balance.

This portion of the data release includes geodetic data used in mass balance analyses. The USGS uses geodetic data to quantify glacier area, glacier hypsometry, and the change in glacier volume and mass (e.g., Cogley and others 2011; Zemp and others 2013; van Beusekom and others, 2010; O’Neel and others 2014). Here we describe these basin-scale data, how they are produced, and the format in which they are preserved and disseminated.

Gridded products comprise the first class of data and include orthorectified images and Digital Elevation Models (DEMs). Prior to the early 2000s, these grids were derived from aerial stereo photography or historic topographic maps. More recently, high-resolution space-borne imagery facilitated DEM and ortho-image production using approaches described herein.

The second class of data are vector geospatial files of glacier margins. These are interpreted products, produced via manual digitization of the boundary between rock and ice identified from ortho-rectified images, or the boundary between neighboring glaciers identified from ice divide velocity maps.

Suggested Citation: McNeil, C. J., Florentine, C. E., Bright, V. A. L., Fahey, M. J., McCann, E., Larsen, C. F., Thoms, E. E., Shean, D. E., McKeon, L. A., March, R. S., Keller, W., Whorton, E. N., O'Neel, S.,and Baker, E. H., 2019, Geodetic data for USGS benchmark glaciers: orthophotos, digital elevation models, and glacier boundaries (ver 1.0, September 2019): U.S. Geological Survey data release, https://doi.org/10.5066/P9R8BP3K.

Metadata

Version History:
First release: September 2019

Glacier Year Orthophotos DEMs
Gulkana
Boundaries
1957 Zip file [120MB]
1967 Zip file [618MB] Zip file [25MB]
1974 Zip file [261MB] Zip file [17MB]
1979 Zip file [1.5GB] Zip file [50MB]
1993 Zip file [517MB] Zip file [197MB]
2005 Zip file [3.7GB] Zip file [83MB]
2007 Zip file [114MB] Zip file [31MB]
2014 Zip file [2.7GB] Zip file [152MB]
2016 Zip file [5.4GB] Zip file [144MB]
Lemon Creek
Boundaries
1948 Zip file [101MB]
1957 Zip file [1GB] Zip file [45MB]
1966 Zip file [152MB]
1974 Zip file [907MB] Zip file [7MB]
1979 Zip file [874MB] Zip file [8MB]
1989 Zip file [630MB] Zip file [25MB]
2014 Zip file [2.2GB]
2016 Zip file [3.8GB]
South Cascade
Boundaries
1958 Zip file [98MB] Zip file [6MB]
1970 Zip file [147MB] Zip file [202MB]
1979 Zip file [592MB] Zip file [276MB]
1986 Zip file [118MB] Zip file [52MB]
1992 Zip file [953MB] Zip file [104MB]
2001 Zip file [2.2GB] Zip file [396MB]
2004 Zip file [1MB]
2008 Zip file [87MB] Zip file [510MB]
2015 Zip file [237MB] Zip file [16MB]
Sperry
Boundaries
1950 Zip file [500KB]
1960 Zip file [500KB]
2005 Zip file [500KB]
2014 Zip file [33MB] Zip file [600KB]
Wolverine
Boundaries
1950 Zip file [101MB] Zip file [2.2MB]
1969 Zip file [197MB] Zip file [74MB]
1972 Zip file [315MB] Zip file [126MB]
1974 Zip file [378MB] Zip file [44MB]
1978 Zip file [998MB]
1979 Zip file [1.2GB] Zip file [10MB]
1995 Zip file [1GB] Zip file [39MB]
1998 Zip file [1GB]
2006 Zip file [94MB] Zip file [47MB]
2008 Zip file [2.5MB]
2011 Zip file [79MB] Zip file [48MB]
2012 Zip file [1.4GB] Zip file [811MB]
2015 Zip file [527MB] Zip file [651MB]
2018 Zip file [3.3GB] Zip file [302MB]