Spatial and temporal variability of annual glacier equilibrium line altitudes in the Southern Alps, New Zealand

Abstract

Assessments of the contribution of meltwater to sea-level rise from mountain glaciers cannot presently account for the considerable spatial inter-catchment and temporal inter-annual variations in annual net glacier mass balance. We therefore analyse annual equilibrium line altitudes (ELAs) to infer the controls on annual net glacier mass-balance variability for 34 glaciers in the central Southern Alps, New Zealand. Elevation, curvature and mean solar radiation receipt (both direct and indirect) during the ablation season can in combination account for up to 95% of the (temporal) variability in the long term ELA and up to c. 85% for a given year. It appears that long-term glacier net mass balance in the Southern Alps is controlled by ablation processes as a function of air temperature which decreases with elevation, and shortwave radiation which causes a positive feedback in ablation by reducing snow and ice cover and increasing albedo. In detail however, the degree to which local topographic variables can explain the differences in (i) the patterns and (ii) in the magnitudes of departures from the trend varies considerably from year to year and across the study region. At least 15Á35% of annual ELA temporal variability is apparently associated with regional weather patterns. Our basic quantification of the interaction on multiple scales of topographic influences on annual ELA and ELAo (steady-state ELA) has implications for understanding inter-and intra-catchment variability in glacier responses to climatic change.

Decadal‐scale changes of the ödenwinkelkees, central austria, suggest increasing control of topography and evolution towards steady state

“…One of the simpler remote sensing approaches is that of the repeated observations of glacier transient snow lines (Chinn ), which at the end of the summer can approximate the equilibrium line altitude ( ELA ), and which can permit high‐resolution spatiotemporal analyses (e.g. Carrivick and Chase ). Perhaps the ultimate expression of the remote sensing approach is represented by glacier inventories, such as the Austrian glacier inventories of 1969 (Gross ) and 1998 (Lambrecht and Kuhn ) and the recently revisited French glacier inventories (Gardent et al .…”

Modelling the evolution of Vadret da Morteratsch, Switzerland, since the Little Ice Age and into the future

“…In addition, these ice losses have an important impact on the local water supply and the hydrological cycle others, 2010, 2012;Kaser and others, 2010;Farinotti and others, 2012), tourism (Elsasser and Bürki, 2002;Pütz and others, 2011) and risk management (Haeberli and others, 1989;Frey and others, 2010;Werder and others, 2010). The rate of glacier retreat is, however, regionally variable and depends on local factors such as mass balance, glacier geometry, debris cover and orientation (Carrivick and Chase, 2011). The resulting variety in glacier settings strongly complicates general statements about the future evolution of glaciers worldwide.…”

Quantifying uncertainty in using multiple datasets to determine spatiotemporal ice mass loss over 101 years at kårsaglaciären, sub‐arctic sweden

“…Balance ratio values borrowed from a nearby glacier will not necessarily be representative because of intercatchment variability in glacier responses to climate change (e.g. Carrivick and Brewer 2004;Carrivick and Rushmer 2009;Carrivick and Chase 2011). Furthermore, the ELA is a long-term average and so for a single time is only valid under steady-state conditions.…”