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1. Introduction The sea level equivalent volumes of the Greenland and Antarctic ice sheets are 7.3 and 56.6 m, respectively, whereas the combined volume of glaciers and small ice caps is far less. Yet, over the next 100 yr their 0.15–0.37-m contribution to sea level rise ( Lemke et al. 2007 ) is expected to dominate that from shrinkage of the great ice sheets (e.g., Ohmura 2004 ; Meier et al. 2007 ). Despite such compelling reasons to be interested in the volumes of glaciers and ice caps
1. Introduction The sea level equivalent volumes of the Greenland and Antarctic ice sheets are 7.3 and 56.6 m, respectively, whereas the combined volume of glaciers and small ice caps is far less. Yet, over the next 100 yr their 0.15–0.37-m contribution to sea level rise ( Lemke et al. 2007 ) is expected to dominate that from shrinkage of the great ice sheets (e.g., Ohmura 2004 ; Meier et al. 2007 ). Despite such compelling reasons to be interested in the volumes of glaciers and ice caps
1. Introduction a. Glaciers and climate variability Variations in climate occur in response to both external forcing and internally generated variability. External forcings are generally defined as mechanisms outside of the climate system that change the underlying radiative balance of the planet; such forcings can be natural (e.g., changes in volcanic or solar activity) or anthropogenic (e.g., greenhouse gas and aerosol emissions and changes in land use) in origin (e.g., IPCC 2013 ). Internal
1. Introduction a. Glaciers and climate variability Variations in climate occur in response to both external forcing and internally generated variability. External forcings are generally defined as mechanisms outside of the climate system that change the underlying radiative balance of the planet; such forcings can be natural (e.g., changes in volcanic or solar activity) or anthropogenic (e.g., greenhouse gas and aerosol emissions and changes in land use) in origin (e.g., IPCC 2013 ). Internal
1. Introduction Melt models are valuable tools for assessing the impact of climate change on glacier mass balance, changes in regional hydrology, and eustatic sea level rise (e.g., Hock 2005 ; Lemke et al. 2007 ). Glacier melt models have been applied over vast regions—even globally—by calibrating the models to well-studied glaciers and applying them unchanged over much larger areas (e.g., De Woul and Hock 2005 ; Oerlemans et al. 2005 ; Raper and Braithwaite 2006 ; Schneeberger et al
1. Introduction Melt models are valuable tools for assessing the impact of climate change on glacier mass balance, changes in regional hydrology, and eustatic sea level rise (e.g., Hock 2005 ; Lemke et al. 2007 ). Glacier melt models have been applied over vast regions—even globally—by calibrating the models to well-studied glaciers and applying them unchanged over much larger areas (e.g., De Woul and Hock 2005 ; Oerlemans et al. 2005 ; Raper and Braithwaite 2006 ; Schneeberger et al
1. Introduction Near-surface air temperature is one of the most important meteorological variables for hydrological and glaciological models in glacierized regions. Turbulent exchange of energy and water vapor fluxes between the glacier surface and the atmosphere can be significantly affected by the surface air temperature ( Ohmura 2001 ). In addition, surface air temperature is a modulating factor of precipitation phase changes (e.g., rain, snow, and sleet), which has remarkable effects
1. Introduction Near-surface air temperature is one of the most important meteorological variables for hydrological and glaciological models in glacierized regions. Turbulent exchange of energy and water vapor fluxes between the glacier surface and the atmosphere can be significantly affected by the surface air temperature ( Ohmura 2001 ). In addition, surface air temperature is a modulating factor of precipitation phase changes (e.g., rain, snow, and sleet), which has remarkable effects
1. Introduction A major goal in current climate research lies in understanding patterns in climate and how they translate to climate proxies. Glaciers are among the most closely studied of these proxies because they respond directly to both snow accumulation and surface energy balance. These, in turn, reflect the precipitation and melt-season temperature of the regional climate ( Ohmura et al. 1992 ). A glacier’s response to this climate is most often characterized by a change in the position
1. Introduction A major goal in current climate research lies in understanding patterns in climate and how they translate to climate proxies. Glaciers are among the most closely studied of these proxies because they respond directly to both snow accumulation and surface energy balance. These, in turn, reflect the precipitation and melt-season temperature of the regional climate ( Ohmura et al. 1992 ). A glacier’s response to this climate is most often characterized by a change in the position
1. Introduction Global climate models consistently predict that climate warming associated with increasing atmospheric concentrations of greenhouse gases will be largest in northern high latitudes ( Houghton et al. 2001 ; Johannessen et al. 2004 ). The response of Arctic glaciers, ice caps, and ice sheets to this warming may therefore be a significant influence on the eustatic component of global sea level rise. In the long term, changes in the volume of the Greenland Ice Sheet are likely to
1. Introduction Global climate models consistently predict that climate warming associated with increasing atmospheric concentrations of greenhouse gases will be largest in northern high latitudes ( Houghton et al. 2001 ; Johannessen et al. 2004 ). The response of Arctic glaciers, ice caps, and ice sheets to this warming may therefore be a significant influence on the eustatic component of global sea level rise. In the long term, changes in the volume of the Greenland Ice Sheet are likely to
1. Introduction Unlike many climate proxy data that are linked to biotic processes, the behavior of glaciers follows physical laws exclusively. The immediate impact of weather and climate governs the glacier volume, through mass and energy exchanges between glacier surface and atmosphere, while the change in glacier extent is the delayed response to these exchanges through ice flow dynamics. A correct understanding of the glacier–climate interaction therefore allows one to infer climate change
1. Introduction Unlike many climate proxy data that are linked to biotic processes, the behavior of glaciers follows physical laws exclusively. The immediate impact of weather and climate governs the glacier volume, through mass and energy exchanges between glacier surface and atmosphere, while the change in glacier extent is the delayed response to these exchanges through ice flow dynamics. A correct understanding of the glacier–climate interaction therefore allows one to infer climate change
; Hansen et al. 2008 ). A realistic description of the spatiotemporal air temperature variation over complex topography influenced by air temperature inversions is essential for snow and ice melt calculations, glacier mass-balance estimates, river breakup simulations, ecological studies, water resource predictions, and for dispersion of pollutants in mountain and basin areas (e.g., Whiteman 1982 ; Chen et al. 1999 ; Singh 1999 ; Whiteman et al. 1999 ; Archer 2004 ; Lundquist and Cayan 2007
; Hansen et al. 2008 ). A realistic description of the spatiotemporal air temperature variation over complex topography influenced by air temperature inversions is essential for snow and ice melt calculations, glacier mass-balance estimates, river breakup simulations, ecological studies, water resource predictions, and for dispersion of pollutants in mountain and basin areas (e.g., Whiteman 1982 ; Chen et al. 1999 ; Singh 1999 ; Whiteman et al. 1999 ; Archer 2004 ; Lundquist and Cayan 2007
1. Introduction Glaciers are key indicators of climate change because of their proximity to melting conditions and the related sensitivity to small climatic fluctuations ( Solomon et al. 2007 ). In particular, the glaciers in the European Alps exhibited strong decreases in extent and thickness during the past two decades, as revealed by satellite observations ( Paul et al. 2007a ) and by comparison of digital elevation models from different points in time ( Bauder et al. 2007 ; Paul and
1. Introduction Glaciers are key indicators of climate change because of their proximity to melting conditions and the related sensitivity to small climatic fluctuations ( Solomon et al. 2007 ). In particular, the glaciers in the European Alps exhibited strong decreases in extent and thickness during the past two decades, as revealed by satellite observations ( Paul et al. 2007a ) and by comparison of digital elevation models from different points in time ( Bauder et al. 2007 ; Paul and
1. Introduction Mass loss from glaciers and ice caps is likely the second largest contribution to global sea level rise after ocean thermal expansion ( Meier et al. 2007 ). Quantifying past contributions from this source is challenging because of the limited availability of measurements of glacier surface mass balance and rates of iceberg calving. Glacier surface mass balance models are widely used to compensate for this lack of measurements and can be used to predict how climate change will
1. Introduction Mass loss from glaciers and ice caps is likely the second largest contribution to global sea level rise after ocean thermal expansion ( Meier et al. 2007 ). Quantifying past contributions from this source is challenging because of the limited availability of measurements of glacier surface mass balance and rates of iceberg calving. Glacier surface mass balance models are widely used to compensate for this lack of measurements and can be used to predict how climate change will
