References Flashcards
ELA = where over one year accumulation of snow = ablation
Benn and Lehmkuhl 2000
Former ELAs = powerful method of quantifying palaeoclimates if e.g. other evidence is lacking
Benn and Lehmkuhl 2000
Knowledge of glacier ELAs = palaeoclimatic data = predict future glacier response to climatic change
Maisch 1995
Mass balance characteristics of glaciers in high-mountain environments complicate the relationship between ELAs and precipitation/air T
- avalanches/debris cover/topographic effects
Benn and Lehmkuhl 2000
Study of glacier mass balance 1946-1995 for 246 glaciers
Western Europe, North America and USSR
Biased towards wetter conditions
Braithwaite 2002
Direct stakes/snowpits method - recognised integration with geodetic/remote sensing would be more useful
Braithwaite 2002
Glaciers mainly gain mass (accumulation) as snow and mostly lose mass (ablation) by melting and iceberg calving
Braithwaite 2002
Local importance of glaciers to societies e.g. HEP or irrigation, or hazards
Braithwaite 2002
Modelling ice/snow melt important for issues e.g. water resource management, avalanche forecasting, glacier dynamics, hydrology/hydrochemistry, climate change
Hock 2005
Modelling of turbulent fluxes and spatial/temporal variability in albedo = major uncertainties
Hock 2005
Typical characteristics of glacier runoff = melt-induced diurnal cyclicality and concentration of annual flow during melt season
Hock 2005
Modelling: High temporal resolution essential for predicting peak flows in glacierised/snow-covered basins
High spatial resolution needed to account for large spatial heterogeneity w.r.t. ice/snow melt due to topography
Hock 2005
Energy balance melt models more properly describe physical processes at glacier surface than temperature-index methods but require much more data
Hock 2005
Further research needed in modelling to focus on links between different energy fluxes and synoptic weather pattern, and investigate potential for operational use in melt forecasting
Hock 2005
Glaciers/ice caps = important contributors to global mean SLR
Jacob et a 2012
Monthly GRACE method from Jan 2003-Dec 2010 for inversion of mass change over all ice-covered regions larger than 100km2
Results:
- GIC excluding Greenland and Antarctica peripheral glaciers and ice caps contributed 0.41+/-0.08mm/yr
- with G/A = 1.06+/-0.19mm/yr
Total agreed with independent estimates within error bars
Jacob et al 2012
Ablation under a debris layer could be estimated from meteorological variables if surface T data (estimation of thermal resistance) of layer is available
Generally good method but surface roughness (large at stagnant areas near glacier terminus) should be noted with care
Nakawo and Young 1982
Understanding water movement through glacier is fundamental to e.g. glacier dynamics/glacier-induced floods/runoff predictions
Fountain and Walder 1998
Firn temporarily stores water and smooths out variations in supply rate (accumulation zone)
In ablation zone, flux of water depends directly on rate of surface melt/rainfall = varies greatly
Fountain and Walder 1998
Describes water flow in a “nonarborescent network”, poorly connected to a well-connected aborescent channel network
Fountain and Walder 1998
Stored water may be released abruptly and catastrophically in the form of outburst floods
Fountain and Walder 1998
Episodic surging of some glaciers due to temporal changes in subglacial hydrology
Fountain and Walder 1998
Near-surface, englacial and subglacial water flow are coupled
Fountain and Walder 1998
Hydrological system components = snow, firn, surface streams; crevasses, moulins and other englacial passages; and basal channels, cavities and till
Fountain and Walder 1998