Results 21 to 30 of about 795 (198)
Firn microstructure in the lock-in zone for three polar ice cores [PDF]
, 2017 Abstract. In order to interpret the paleoclimatic record stored in the air enclosed in polar ice cores, it is crucial to understand the fundamental lock-in process. Within the porous firn, bubbles are sealed continuously until the respective horizontal layer reaches a critical porosity. Present-day firn models use a postulated temperature dependence of
Christoph Florian Schaller +2 more
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Modeling enhanced firn densification due to strain softening [PDF]
The Cryosphere, 2022 In the accumulation zone of glaciers and ice sheets snow is transformed into glacial ice by firn densification. Classically, this process is assumed to solely depend on temperature and overburden pressure, which is controlled by the accumulation rate ...
F. M. Oraschewski +2 more
doaj +1 more source
The Community Firn Model (CFM) v1.0 [PDF]
Geoscientific Model Development, 2020 Models that simulate the evolution of polar firn are important for several applications in glaciology, including converting ice-sheet elevation change measurements to mass change and interpreting climate records in ice cores.
C. M. Stevens +8 more
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Pure rotational Raman spectroscopy applied to N2/O2 analysis of air bubbles in polar firn
Journal of Glaciology, 2021 Earlier gas measurements of firn air (atmosphere in open pore channels) at polar sites have revealed the occurrence of gas fractionation phenomena during bubble close-off, in addition to well-known thermal and gravitational gas separation.
Hiroshi Ohno +2 more
doaj +1 more source
Antarctic Firn Characterization via Wideband Microwave Radiometry
Remote Sensing, 2022 Recent studies have demonstrated that wideband microwave radiometers provide significant potential for profiling important subsurface polar firn characteristics necessary to understand the dynamics of the cryosphere and predict future changes in ice and ...
Rahul Kar +4 more
doaj +1 more source
Methyl bromide, other brominated methanes, and methyl iodide in polar firn air [PDF]
Journal of Geophysical Research, 2001 W T Sturges, S A Penkett, J Chappellaz
exaly +2 more sources
Modelling of the densification of polar firn: characterization of the snow–firn transition [PDF]
Annals of Glaciology, 1998 The transformation of dry snow to firn is described by the transition between densification by deformationless restacking and densification by power-law creep. The observed decrease with temperature of the density at the snow-firn transition seems to result from the competition between grain-boundary sliding and power-law creep. These two densification
Arnaud, Laurent +4 more
openaire +3 more sources
Impact of physical properties and accumulation rate on pore close-off in layered firn [PDF]
The Cryosphere, 2014 Investigations into the physical characteristics of deep firn near the lock-in zone through pore close-off are needed to improve understanding of ice core records of past atmospheric composition. Specifically, the permeability and microstructure profiles
S. A. Gregory, M. R. Albert, I. Baker
doaj +1 more source
Polar Firn Densification and Grain Growth [PDF]
Annals of Glaciology, 1982 A 50 m firn core from Dome C, East Antarctica, was found to consist of coarse firn, which comprised 90 to 95% of the core, and fine firn. Coarse firn was characterized by large crystals with a vertical shape orientation near the surface, connected to nearest neighbors by relatively large necks in a structure different from closest packing.
Richard B. Alley +2 more
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Crystal growth rates in polar firn [PDF]
Annals of Glaciology, 1993 Continuous crystal-size measurements made on the G6 Antarctic ice core (100m deep) show enhanced growth rates above a depth of 30 m (Zone 1) and in the interval between 70 and 80 m (Zone 2). Crystal growth in Zone 1 most probably takes place by a process of sublimation and condensation.
Hitoshi Shoji +3 more
openaire +1 more source