Effects of molecular diffusion on trapped gas composition in polar ice cores

Ikeda-Fukazawa, Tomoko; Fukumizu, Kenji; Kawamura, Kenji; Aoki, Shuji; Nakazawa, Takakiyo; Hondoh, Takeo

doi:10.1016/j.epsl.2004.11.011

Cited by 77 publications

(132 citation statements)

References 28 publications

Supporting

Mentioning

108

Contrasting

Order By: Relevance

“…Again at 216 K, X n of O 2 and N 2 within ice lattice are 2.3 Â 10 À10 and 1.4 Â 10 À10 mol m ice À3 Pa À1 , respectively [Ikeda-Fukazawa et al, 2005]. Then, the permeation coefficient D n X n is 3.6 Â 10 À21 and 1.6 Â 10 À21 mol m ice À1 s À1 Pa…”

Section: Typical Changes Of Tmentioning

confidence: 96%

“…For example, overburden pressures were estimated from the density profile in Figure 3a and they are higher than the atmospheric pressure by 0.45 MPa and 0.65 MPa at z s = 78 m and z c = 104 m, respectively. It has been presumed that the differences in pressure between closing/ closed air bubbles and air in open pores drive two processes: effusion of air from closing bubbles to open pores through a small opening [Bender, 2002] and permeation of gas molecules from closed bubbles to open pores through the ice lattice [Huber et al, 2006;Ikeda-Fukazawa et al, 2005;Severinghaus and Battle, 2006]. The former process, Dp-driven effusion, was proposed by Bender [2002] as a mechanism for gas fractionation.…”

Section: A Model For Modulation Of Conditions For Gas Transport By Lomentioning

confidence: 99%

“…In contrast, the latter process, Dp-driven permeation of gas molecules, causes both fractionation of gas molecules and a decrease in the air content of bubbles. Size-dependent fractionation occurs due to the preferential exclusion of small gases from shrinking bubbles by molecular diffusion through the ice lattice [Huber et al, 2006;Ikeda-Fukazawa et al, 2005;Severinghaus and Battle, 2006]. Thus, both accumulation of O 2 -enriched gas in the residual firn air and depletion of O 2 /N 2 ratio in air bubbles occur in the bubble formation zone.…”

Section: A Model For Modulation Of Conditions For Gas Transport By Lomentioning

confidence: 99%

“…[49] Ikeda-Fukazawa et al [2004, 2005 estimated the diffusion coefficients of O 2 and N 2 within an ice lattice based on molecular dynamics simulations. The diffusion coefficients of O 2 and N 2 within ice lattice are 1.6 Â 10 À11 m 2 s À1 and 1.2 Â 10 À11 m 2 s À1 , respectively, at 216 K, at the average present temperature at Dome Fuji .…”

Section: Diffusion Lengthmentioning

confidence: 99%

“…This size-dependent fractionation occurs in response to the preferential exclusion of small gases from shrinking bubbles to the residual firn air (open pores) by molecular diffusion through the ice lattice driven by pressure differences [Huber et al, 2006;IkedaFukazawa et al, 2005;Severinghaus and Battle, 2006]. Fractionation of the O 2 /N 2 ratio also occurs between bubbles and clathrate hydrate crystals within the ice sheet [Bender et al, 1995;Ikeda-Fukazawa et al, 2001;Ikeda et al, 1999] and between clathrate hydrate crystals and the atmosphere during the storage of ice cores after drilling [Ikeda-Fukazawa et al, 2004;Ikeda-Fukazawa et al, 2005]. Bender [2002] discovered that variations in the O 2 / N 2 ratio of trapped gases occur cyclically, with ages between ca 160 -385 ka in the Vostok (Figure 1) ice core.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off

et al. 2009

Self Cite

View full text Add to dashboard Cite

[1] The evolution of the structure of a 112.59 m long firn core recovered at Dome Fuji, East Antarctica, was investigated in order to improve understanding of firn densification and bubble formation processes, which are important for interpreting local insolation proxies used for astronomical dating of deep ice cores. Using selected samples, we measured physical properties including (1) the relative dielectric permittivities in both the vertical and horizontal planes, (2) the bulk density at a resolution of millimeters, (3) the three-dimensional geometric structure of pore space, and (4) crystal orientation fabrics. We found that the firn at Dome Fuji contains horizontal strata with thicknesses of several centimeters. Near the surface of the ice sheet, these strata are characterized by contrasting bulk density. Earlier field studies suggest that summer insolation causes densification of surface firn. Down to $30 m, density maxima exhibited a clear positive correlation with the strength of structural anisotropy and c axis clustering around the vertical. In contrast, the correlation is negative in deeper firn, confirming previous findings that initially less dense firn became denser than initially dense firn. In addition, numerous examples of textures indicating that deformation preferentially occurred in weaker layers were found. Moreover, the initially dense firn layers were more permeable for air near the bottom of firn. We propose a model linking firn properties with conditions for the gas transport processes near the bottom of firn. The model explains how stronger insolation can lead to bulk ice with a lower O 2 /N 2 ratio and smaller total gas content.Citation: Fujita, S., J. Okuyama, A. Hori, and T. Hondoh (2009), Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off,

show abstract

Section: Typical Changes Of Tmentioning

confidence: 96%

Section: A Model For Modulation Of Conditions For Gas Transport By Lomentioning

confidence: 99%

Section: A Model For Modulation Of Conditions For Gas Transport By Lomentioning

confidence: 99%

Section: Diffusion Lengthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off

et al. 2009

Self Cite

View full text Add to dashboard Cite

show abstract

Arctic and Antarctic sea ice acts as a sink for atmospheric CO₂ during periods of snowmelt and surface flooding

et al. 2013

View full text Add to dashboard Cite

[1] In this study, we present evidence that Antarctic and Arctic sea ice act as sink for atmospheric CO 2 during periods of snowmelt and surface flooding. The CO 2 flux measured directly at the flooded sea ice surface (F flood ) constituted a net CO 2 sink of À1.1 6 0.9 mmol C m À2 d À1 (mean 6 1 SD), which was an order of magnitude higher than the flux measured at the snow-air surface (F snow ) and bare ice surface (F ice ). The F snow /F flood ratio decreased with increasing water equivalent of snow and superimposed-ice, suggesting that the properties of snow and superimposed-ice formation affect the magnitude of the CO 2 flux. The F snow /F flood ratio ranged from 0.1 to 0.5, illustrating that 50-90% of the potential flux at the flooded surface was reduced due to the presence of snow/superimposed-ice. Hence, snow cover properties and superimposed-ice play an important role in the CO 2 fluxes across the sea ice-snow-atmosphere interface.Citation: Nomura, D., M.A. Granskog, P.Assmy, D. Simizu, and G. Hashida (2013), Arctic and Antarctic sea ice acts as a sinkfor atmospheric CO 2 during periods of snowmelt and surface flooding,

show abstract

Evolution of the stable carbon isotope composition of atmospheric CO₂ over the last glacial cycle

et al. 2016

View full text Add to dashboard Cite

We present new 13 C measurements of atmospheric CO 2 covering the last glacial/interglacial cycle, complementing previous records covering Terminations I and II. Most prominent in the new record is a significant depletion in 13 C(atm) of 0.5‰ occurring during marine isotope stage (MIS) 4, followed by an enrichment of the same magnitude at the beginning of MIS 3. Such a significant excursion in the record is otherwise only observed at glacial terminations, suggesting that similar processes were at play, such as changing sea surface temperatures, changes in marine biological export in the Southern Ocean (SO) due to variations in aeolian iron fluxes, changes in the Atlantic meridional overturning circulation, upwelling of deep water in the SO, and long-term trends in terrestrial carbon storage. Based on previous modeling studies, we propose constraints on some of these processes during specific time intervals. The decrease in 13 C(atm) at the end of MIS 4 starting approximately 64 kyr B.P. was accompanied by increasing [CO 2 ]. This period is also marked by a decrease in aeolian iron flux to the SO, followed by an increase in SO upwelling during Heinrich event 6, indicating that it is likely that a large amount of 13 C-depleted carbon was transferred to the deep oceans previously, i.e., at the onset of MIS 4. Apart from the upwelling event at the end of MIS 4 (and potentially smaller events during Heinrich events in MIS 3), upwelling of deep water in the SO remained reduced until the last glacial termination, whereupon a second pulse of isotopically light carbon was released into the atmosphere.

show abstract

Effects of molecular diffusion on trapped gas composition in polar ice cores

Cited by 77 publications

References 28 publications

Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off

Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off

Arctic and Antarctic sea ice acts as a sink for atmospheric CO₂ during periods of snowmelt and surface flooding

Evolution of the stable carbon isotope composition of atmospheric CO₂ over the last glacial cycle

Contact Info

Product

Resources

About

Effects of molecular diffusion on trapped gas composition in polar ice cores

Cited by 77 publications

References 28 publications

Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off

Metamorphism of stratified firn at Dome Fuji, Antarctica: A mechanism for local insolation modulation of gas transport conditions during bubble close off

Arctic and Antarctic sea ice acts as a sink for atmospheric CO2 during periods of snowmelt and surface flooding

Evolution of the stable carbon isotope composition of atmospheric CO2 over the last glacial cycle

Contact Info

Product

Resources

About

Arctic and Antarctic sea ice acts as a sink for atmospheric CO₂ during periods of snowmelt and surface flooding

Evolution of the stable carbon isotope composition of atmospheric CO₂ over the last glacial cycle