Quantifying the effects of climate and surface change on glacier mass balance

Abstract

When a mass balance is computed using an outdated map, that computation does not reveal the actual mass change. But older maps often must be used for practical reasons. We present a method by which, with a few additional measurements each year, a mass balance computed with an outdated map can be transformed into an actual mass change. This is done by taking into account the influence of changes in areal extent and changes in the surface elevation of the glacier since the map was made. This method is applied to South Cascade Glacier, Washington, U.S.A., as an example. The computed cumulative mass balance from 1970 to 1997 would have been 16% too negative if the 1970 map had not been updated.While the actual volume change of a glacier is relevant to hydrological studies, the change that would have occurred on a constant (or static) surface is more relevant to certain glacier dynamics problems and most climate problems. We term this the reference-surface balance and propose that such a balance, which deliberately omits the influence of changes in area and surface elevation, is better correlated to climatic variations than the conventional one, which incorporates those influences.

Analysis of the mass balance time series of glaciers in the Italian Alps

“…Rapid geometric changes may also lead to a nonlinear response of B a to atmospheric changes, at least for some glaciers (Elsberg et al, 2001;Paul, 2010). For example, the multiple regression residuals of the Careser Glacier, which were mostly positive in the 1980s, 1990s and 2000s, became predominantly negative after 2008 (Fig.…”

“…This assessments can be obtained using modern techniques, such as the multi-temporal differencing of digital elevation models, which enable the comparison of mass loss rates in the last years/decades, by means of the geodetic method, over entire regions or mountain ranges (e.g., Paul and Haeberli, 2008;Abermann et al, 2011;Carturan et al, 2013b;Berthier et al, 2014;Fischer et al, 2015). The geodetic mass balance should also help to control the glacier-wide B a series measured with the direct glaciological method and to construct a constant-geometry mass balance record (Elsberg et al, 2001) to be connected to climatic drivers.…”

Mass balance of glaciers and ice caps: Consensus estimates for 1961–2004

“…[16] Although single-glacier balance estimates usually account for temporal changes of the glacier's area (that is, they are not ''reference-surface balances'' as defined by Elsberg et al [2001]), little is known of regional changes in extents of glacierization. Observed rates range from À0.03% a À1 for the Russian Arctic (1952Glazovskiy and Macheret [2006]) to À0.62% a À1 for the Swiss Alps (1973-1999Paul et al [2004]).…”

Quantifying changes and trends in glacier area and volume in the Austrian Ötztal Alps (1969-1997-2006)

“…Besides forming an important source for the determination of glacier extent as its main purpose, periodically updated glacier boundaries are a necessary input for accurate mass balance studies (e.g. Elsberg et al, 2001;Fischer et al, 2009) and modelling of the future glacier extent. A sequence of glacier inventories allows for the quantification of the accelerated glacier change in the context of a changing climate.…”

“…Detailed maps of selected glaciers in the study area were produced between 1969 and 1997 (e.g. Hintereisferner: Kuhn, 1979, or Vernagtferner: Heipke et al, 1994Endres, 2001).…”