Extreme firn metamorphism: impact of decades of vapor transport on near-surface firn at a low-accumulation glazed site on the East Antarctic plateau

Abstract

ABSTRACT. Snow and firn properties control the transport of vapor, gases and water between the atmosphere and the underlying strata. An understanding of this transport and the properties that control it is important for predicting air-snow transfer of chemical species and for interpreting ice cores. Remote-sensing images of East Antarctica show large areas of alternating light and dark bands. These low-amplitude, long-wavelength features have glazed downwind faces and rough upwind faces and are called megadunes. The first linked measurements of the permeability and the associated microstructure for a glazed area within a well-defined megadune area are reported in this paper. Permeability and density were measured, along with grain-scale properties derived from digital image processing of preserved thick sections, at this cold, low-accumulation glazed site. A clear layering pattern exists. In the top meter the firn density ranges from 0.24 to 0.50 g cm -3

Summertime evolution of snow specific surface area close to the surface on the Antarctic Plateau

“…More generally, shortcomings in parameterizing the surface boundary layer on the Antarctic Plateau sometimes conduct to poorly simulated air temperature and wind profiles (Genthon et al, 2010), which probably explains part of these difference as well. Indeed, besides precipitation, surface snow at Dome C is also largely shaped by snow drift, which redistributes snow and controls density and SSA in the topmost centimetres (Gallée et al, 2001;Albert et al, 2004). Snow drift also generates spatial variability of snow properties close to the surface because it can accumulate fresh snow at some locations and make apparent older snow at other locations through erosion (Libois et al, 2014a), which is illustrated by the large standard deviation of surface SSA measurements in Fig.…”

“…The resulting dependence between snow physical properties and the energy budget of the snowpack gives rise to feedbacks (e.g. Albert et al, 2004) and is therefore of great interest to climate studies. This highlights the need to identify the main processes which drive surface snow evolution on the Antarctic Plateau.…”

Tomography-based monitoring of isothermal snow metamorphism under advective conditions

“…In addition, Colbeck (1997b) confirmed the rapid decrease of airflow velocities inside a snowpack. Advective flow of air may have a direct effect on snow-air exchange processes related to atmospheric chemistry (Clifton et al, 2008;Grannas et al, 2007), and snow metamorphism (Albert and Gilvary, 1992;Albert et al, 2004), and can change the chemical composition of trapped atmospheric gases in ice cores (Legrand and Mayewski, 1997;Neumann and Waddington, 2004;Severinghaus et al, 2010). However, no prior studies have experimentally analyzed the effect of saturated airflow on the vapour transport and the recrystallization of the snow crystals using non-destructive technique in time-lapse experiments.…”

An automated system for continuous measurements of trace gas fluxes through snow: an evaluation of the gas diffusion method at a subalpine forest site, Niwot Ridge, Colorado

“…Uncertainties in flux estimates using the diffusion model Snow permeability and gas transport are related to snow density (Albert and Hardy 1995;Albert and Shultz 2002;Albert et al 2004) as permeability is affected by porosity and tortuosity, even though there is no direct relationship between porosity, tortuosity, and permeability . In our flux calculation, gas diffusivity, following Eq.…”