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Glacier-Wide Mass Balance and Compiled Data Inputs: Juneau Icefield Glaciers

Data Download [473KB] | Metadata | AK Science Portal | Project Site | Date Range: 1945 - 2019

Since the 1940s, the Juneau Icefield Research Program (JIRP) has been measuring surface mass balance on the Juneau Icefield. This is the longest ongoing program of its kind in North America. The program nominally occurs between late June and late August, traversing between Juneau, Alaska and Atlin, British Columbia. JIRP has examined the surface mass balance of the Juneau Icefield since 1946, with principal efforts focused on Lemon Creek Glacier and Taku Glacier. Glaciological, geodetic, and meteorological data have been collected by JIRP to characterize the interaction between the climate and glaciers of the Juneau Icefield. Direct field measurements of point glaciological data are combined with weather and geodetic data to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). The basic analysis framework (O'Neel, 2019; McNeil et. al, 2019) is the same at each glacier to enable cross-comparison between output time series. For Taku and Lemon Creek glaciers, temperature lapse rates are optimized using on-icefield weather data. This changes the degree day factor in the melt model, giving small post-geodetic calibration differences on the order of 2-3 cm. Details are described in McNeil (2019). Vocabulary used follows Cogley and others (2011) Glossary of Glacier Mass Balance. This portion of the data release includes glacier wide mass balance solutions for Taku and Lemon Creek Glaciers, as well as the refined inputs used in these calculations. Input data are of three types: 1) time-variable area altitude distribution (AAD); 2) time series of point water balance at long term sites (with secondary sites given in recent years); 3) weather data from nearby stations, either installed along the glacier margins or taken from a nearby site if continuous glacier-adjacent data is unavailable. The USGS runs a coded analysis to transform the three input data types to the output glacier-wide data. Output data represent surface mass balance estimates. The output solution is a geodetically calibrated, conventional glacier-wide mass balance, which represents our preferred solution. Conventional glacier-wide mass balance from direct observations without calibration can be easily derived by using the geodetic calibration coefficients provided, if desired. We do not explicitly account for basal or englacial accumulation or ablation. Mass balances are reported in water equivalent (w.e.) units, and often represent integration of multiple field measurements. Whenever possible, we average multiple field measurements to account for surface roughness and measurement errors. Additional data for Lemon Creek Glacier, part of the Juneau Icefield, is available in a separate data release of USGS Benchmark Glacier data at It is not included here to avoid duplication.

Provisional data for the current year are included in this version of the release. In the next update, following glacier fieldwork in Spring of the following calendar year, numbers for the current year will be finalized and re-released. In cases where fall fieldwork in the current year preceded the end of the summer melt season, the amount of ablation in the current years' summer is likely underestimated.

Author(s): McNeil, C. J.; Campbell, S. W.; O'Neel, S. R.; Baker, E. H.

Suggested Citation:
McNeil, C. J., Campbell, S. W., O'Neel, S. R. and Baker, E. H., 2019, Glacier-wide mass balance and compiled data inputs: Juneau Icefield glaciers (ver. 2.0, March 2021): U.S. Geological Survey data release,

Version History:
First release: November 2019
Revised: March 2021 (ver. 2.0)

DataID: 262 | doi:10.5066/P9YBZ36F | Date Posted Online: 2019-11-12 | Last Updated: 2021-04-07 13:01:17

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