Results 11 to 20 of about 7,958 (231)
Evidence of dynamic recrystallization in polar firn [PDF]
Journal of Geophysical Research: Solid Earth, 2009 Microstructural analyses have been performed on polar firn from the European Project for Ice Coring in Antarctica drilling site in Dronning Maud Land, Antarctica. The results derived from images of the firn structure in microscopic resolution indicate that dynamic recrystallization is active in firn at all depths, and it dominates the evolution of the ...
Sepp Kipfstuhl +8 more
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Microwave Emissivity and Accumulation Rate of Polar Firn [PDF]
Journal of Glaciology, 1977 AbstractRadiative transfer theory is formulated to permit a meaningful definition of emissivity for bulk emitting media such as snow. The emissivity in the Rayleigh-Jeans approximation is then the microwave brightness temperature TB divided by an effective physical temperature 〈T〉.
H. Jay Zwally
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Concerning the Deposition and Diagenesis of Strata in Polar Firn [PDF]
Journal of Glaciology, 1988 AbstractDepth hoar in polar firn forms when large temperature gradients act on low-density firn, but high-density firn does not develop into depth hoar. Low densities in firn may be depositional (burial of surface hoar or still-air snowfall) or diagenetic (mass loss to the free atmosphere, typically in autumn); however, diagenesis is sufficiently ...
Richard B. Alley
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The densification of layered polar firn [PDF]
Journal of Geophysical Research: Earth Surface, 2011 High-resolution density profiles of 16 firn cores from Greenland and Antarctica are investigated in order to improve the understanding of densification of layered polar firn.A resolution of 1 to 5 mm enables us to study the detailed densification processes and the evolution of the layering and the resulting variability in density with increasing depth.
M. W. Hörhold +4 more
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Long-lived halocarbon trends and budgets from atmospheric chemistry modelling constrained with measurements in polar firn [PDF]
Atmospheric Chemistry and Physics, 2009 The budgets of seven halogenated gases (CFC-11, CFC-12, CFC-113, CFC-114, CFC-115, CCl<sub>4</sub> and SF<sub>6</sub>) are studied by comparing measurements in polar firn air from two Arctic and three Antarctic sites, and ...
P. Martinerie +8 more
doaj +3 more sources
Annual layers in polar firn detected by Borehole Optical Stratigraphy [PDF]
Geophysical Research Letters, 2003 We have developed a system called Borehole Optical Stratigraphy which can detect annual layers in boreholes in polar firn. Borehole Optical Stratigraphy consists of a downhole camera package and post‐processing routines, which allow us to measure the intensity of light emitted from an on‐board source and returned from the borehole wall.
R. L. Hawley +3 more
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Kinematic waves in polar firn stratigraphy [PDF]
Journal of Glaciology, 2011 AbstractRadar studies of firn on the ice sheets have revealed complex folds on its internal layering that form from the interplay of snow accumulation and ice flow. A mathematical theory for these fold structures is presented, for the case where the radar cross section lies along the ice-flow direction and where the accumulation rate and ice-flow ...
Felix Ng, Edward C. King
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Kinetic fractionation of gases by deep air convection in polar firn [PDF]
Atmospheric Chemistry and Physics, 2013 A previously unrecognized type of gas fractionation occurs in firn air columns subjected to intense convection. It is a form of kinetic fractionation that depends on the fact that different gases have different molecular diffusivities.
K. Kawamura +7 more
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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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