Modelled climate sensitivity of the mass balance of Morteratschgletscher and its dependence on albedo parameterization

Abstract

This paper presents a study of the climate sensitivity of the mass balance of Morteratschgletscher in Switzerland, estimated from a two-dimensional mass balance model. Since the albedo scheme chosen is often the largest error source in mass balance models, we investigated the impact of using different albedo parameterizations on the climate sensitivity of the mass balance. We first ran the mass balance model for the period 1980 to 2002 and calculated the mass balance sensitivity by perturbing the air temperature by values ranging from −2 to +2 K and precipsitation by values ranging from −20 to +20%. The albedo parameterization that we used for these simulations relates the snow albedo to snow age and snow depth, whereas it considers the ice albedo constant in time and space. The mass balance sensitivity to temperature and precipitation was estimated at −59 cmWE year −1 K −1 and at 17 cmWE year −1 per 10% respectively (cmWE: centimetres water equivalent). Then, we used three other albedo parameterizations. One parameterization uses ice albedo values that vary in space and were acquired from a Landsat image. Another parameterization calculates the snow albedo from accumulated daily maximum temperatures since snowfall. The third parameterization is the simplest and uses two constant albedo values, one for snow and one for ice. The differences between sensitivities calculated from the different albedo parameterizations were generally small. However, when the simplest parameterization was used, the mass balance sensitivity to temperature decreased to −52 cmWE year −1 K −1 . This is mainly due to the constant snow albedo, which implies that the albedo feedback is not fully considered. For an accurate estimate of the mass balance sensitivity, the albedo parameterization should capture the process of a decreasing snow albedo when a snow pack gets older or thinner.

Climate trends and glacier retreat in the Cordillera Blanca, Peru, revisited

“…The aim is to estimate the amount of precipitation needed to balance an observed rise in the snowline during precipitation events. The sensitivity of the glacier mass balance to albedo changes is estimated similar to Klok and Oerlemans (2004). The main assumption of this experiment is that the elevation of the snowline has increased and the elevation band between the former and the current snowline has changed from snow-covered to bare ice.…”

“…This example based on Shallap glacier is very simple and the sensitivity of glaciers to changes in temperature and precipitation depends on several factors. For example, glaciers with a large accumulation area are more sensitive to changes in precipitation and would benefit more from an increase (Klok and Oerlemans, 2004).…”

Imaging spectroscopy to assess the composition of ice surface materials and their impact on glacier mass balance

“…However, albedo is known to be a crucial parameter for glacier ablation (e.g. Jonsell, Hock, & Holmgren, 2003;Klok & Oerlemans, 2004). We therefore tested the impact of using spatially distributed albedo maps (Fig.…”

Air temperature variability over three glaciers in the Ortles–Cevedale (Italian Alps): effects of glacier fragmentation, comparison of calculation methods, and impacts on mass balance modeling

“…It regulates the accumulation processes via the snowfall elevation limit and the snowpack metamorphism (which affect redistribution phenomena) and regulates the ablation processes via turbulent fluxes and long-wave radiation. It is also closely related to important feedbacks such as albedo, the mass balanceelevation feedback, and the glacier cooling effect, which changes as glaciers adjust their size in response to climatic fluctuations (Khodakov, 1975;Klok and Oerlemans, 2004;Paul et al, 2005;Raymond and Neumann, 2005;Haeberli et al, 2007;Fischer, 2010;Paul, 2010;Carturan et al, 2013).…”