Results 41 to 50 of about 795 (198)

Gas diffusivity and permeability through the firn column at Summit, Greenland: measurements and comparison to microstructural properties [PDF]

The Cryosphere, 2014
The physical structure of polar firn plays a key role in the mechanisms by which glaciers and ice sheets preserve a natural archive of past atmospheric composition. This study presents the first measurements of gas diffusivity and permeability along with
A. C. Adolph, M. R. Albert
doaj   +1 more source

Modelling L-band microwave brightness temperature time series for firn aquifers [PDF]

The Cryosphere
Firn aquifers are important in polar ice sheet hydrology and the associated mass and energy transport processes. Although the firn aquifer extent has been mapped using passive microwave satellite observations, models for predicting the L-band brightness ...
H. Xu, L. Tsang, J. Miller, B. C. Medley, J. T. Johnson   +4 more
doaj   +1 more source

From atmospheric water isotopes measurement to firn core interpretation in Adélie Land: a case study for isotope-enabled atmospheric models in Antarctica [PDF]

The Cryosphere, 2023
In a context of global warming and sea level rise acceleration, it is key to estimate the evolution of the atmospheric hydrological cycle and temperature in polar regions, which directly influence the surface mass balance of the Arctic and Antarctic ice ...
C. Leroy-Dos Santos, C. Leroy-Dos Santos, E. Fourré, C. Agosta, M. Casado, A. Cauquoin, M. Werner, B. Minster, F. Prié, O. Jossoud, L. Petit, A. Landais   +11 more
doaj   +1 more source

Modelling the transition from grain-boundary sliding to power-law creep in dry snow densification

Journal of Glaciology, 2022
This paper presents a physics-based macroscale model for the densification of dry snow which provides for a smooth transition between densification by grain-boundary sliding (stage 1) and densification by power-law creep (stage 2).
Elizabeth M. Morris, Lynn N. Montgomery, Robert Mulvaney   +2 more
doaj   +1 more source

Comparison of elastic moduli from seismic diving-wave and ice-core microstructure analysis in Antarctic polar firn

Annals of Glaciology, 2019
We compared elastic moduli in polar firn derived from diving wave refraction seismic velocity analysis, firn-core density measurements and microstructure modelling based on firn-core data.
Rebecca Schlegel, Anja Diez, Henning Löwe, Christoph Mayer, Astrid Lambrecht, Johannes Freitag, Heinrich Miller, Coen Hofstede, Olaf Eisen   +8 more
doaj   +1 more source

Can the carbon isotopic composition of methane be reconstructed from multi-site firn air measurements? [PDF]

Atmospheric Chemistry and Physics, 2013
Methane is a strong greenhouse gas and large uncertainties exist concerning the future evolution of its atmospheric abundance. Analyzing methane atmospheric mixing and stable isotope ratios in air trapped in polar ice sheets helps in reconstructing the ...
C. J. Sapart, P. Martinerie, E. Witrant, J. Chappellaz, R. S. W. van de Wal, P. Sperlich, C. van der Veen, S. Bernard, W. T. Sturges, T. Blunier, J. Schwander, D. Etheridge, T. Röckmann   +12 more
doaj   +1 more source

Vertical profile of snow-firn density in the vicinity of Vostok station, Central Antarctica

Лëд и снег, 2023
The density of the snow and firn thickness is one of the fundamental and most important physical properties of the polar ice sheets. The data on density is used for reconstructing the past snow accumulation rate variability based on firn core studies ...
A. A. Ekaykin, K. B. Tchikhatchev, A. N. Veres, V. Ya. Lipenkov, N. A. Tebenkova, A. V. Turkeev   +5 more
doaj   +1 more source

Texture of Polar Firn for Remote Sensing [PDF]

Annals of Glaciology, 1987
Knowledge of the texture of polar firn is necessary for interpretation of remotely sensed data. We find that dry polar firn is an irregularly stratified, anisotropic medium. Grains in firn may be approximated as prolate spheroids with average axial ratios as high as 1.2 or greater and with a preferred orientation of long axes clustered around the ...
openaire   +2 more sources

Transformation process observations of polar firn to ice [PDF]

Annals of Glaciology, 1993
The transformation of snow to ice under compressive stress is a very slow process unless meltwater is present. A qualitative measure of permeability variation with depth was continuously determined for various shallow-ice cores from the dry-snow zones in both Greenland and Antarctica to investigate this transformation process.
Langway, C.C. jr., Shoji, H., Mitani, A., Clausen, Henrik B.   +3 more
openaire   +1 more source

A record of volcanic eruptions over the past 2,200 years from Vostok firn cores, central East Antarctica

Frontiers in Earth Science, 2023
Introduction: The products of volcanic eruptions found in the snow, firn and ice deposits of the polar ice sheets are precious sources of information on the volcanic forcing of the climate system in the recent or remote past.
Arina N. Veres, Alexey A. Ekaykin, Alexey A. Ekaykin, Liudmila P. Golobokova, Tamara V. Khodzher, Olga I. Khuriganowa, Alexey V. Turkeev   +6 more
doaj   +1 more source