Snow Stratigraphic Studies At Dome C, East Antarctica: An Investigation Of Depositional and Diagenetic Processes

Palais, Julie M.; Whillans, I. M.; Bull, C.

doi:10.1017/s0260305500002846

Cited by 34 publications

(30 citation statements)

References 1 publication

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“…A number of other meteorological properties a¡ect physical properties of snow and could therefore in£uence O 2 / N 2 . Winds produce high-density surface snow crusts [28,29]. They also induce convection in the snowpack, leading to water vapor transport and the formation of faceted crystals [30].…”

Section: Relationship Between O 2 /N 2 and Insolationmentioning

confidence: 99%

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Orbital tuning chronology for the Vostok climate record supported by trapped gas composition

Bender

2002

Earth and Planetary Science Letters

222

155

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We present data on the O 2 /N 2 ratios of trapped gas samples for the entire length of the Vostok climate record. As in other cores, O 2 /N 2 ratios in these samples are less than the atmospheric ratio, by a small and variable amount, because O 2 is selectively excluded during the gas trapping process, and because O 2 is also preferentially lost in poorly preserved core samples. Samples younger than 150 ka have large and variable O 2 depletions. Samples older than 200 ka have O 2 /N 2 ratios that replicate well and vary smoothly with depth. We plot O 2 /N 2 ratios of well replicated samples older than 160 ka, using a chronology derived by matching the N 18 O of paleoatmospheric O 2 (N 18 O atm ) to northern hemisphere June insolation. On this timescale, O 2 /N 2 varies coherently with local (78 ‡S) summertime insolation. Based on time series analysis of the O 2 /N 2 record and the dynamics of snow metamorphism at the surface, we conclude that summertime insolation influences physical properties of ice grains that control the degree of O 2 exclusion during bubble closeoff. O 2 /N 2 in Vostok is thus arguably a property that records local summertime insolation and can be used to test independent chronologies for the core. We show that the N 18 O atm chronology, supported by the coincidence of O 2 /N 2 ratios with insolation, is also compatible with recent radiometric dating of corals from high sea stands. We further successfully test the N 18 O atm tuning chronology by showing that it predicts a chronology for the GISP2 core which is essentially indistinguishable from the standard GISP2 chronology and, therefore, in excellent agreement with the radiometric chronology of Hulu Cave, China. An accurate chronology for the Vostok ice core is now in place. ß

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Section: Relationship Between O 2 /N 2 and Insolationmentioning

confidence: 99%

“…This increase induces sublimation (depth hoar formation), upward migration of water vapor, and its subsequent deposition in colder, shallower snow (e.g., [29]). Depth hoar layers are common features of snow on the Antarctic Plateau [28,37].…”

Section: Variable Insolation and The Surface Metamorphism Of Snowmentioning

confidence: 99%

Orbital tuning chronology for the Vostok climate record supported by trapped gas composition

Bender

2002

Earth and Planetary Science Letters

222

155

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“…Depth hoar formation, for example, has been seen at Taylor Dome and Dome C (Alley et al 1982;Palais et al 1982;Waddington and Morse 1994). In the ®rn, depth hoar will be isotopically heavier than vapour because of non-equilibrium fractionation during condensation.…”

Section: Possible Mechanisms For High-frequency Deuterium Excess¯uctumentioning

confidence: 99%

Holocene hydrological cycle changes in the Southern Hemisphere documented in East Antarctic deuterium excess records

et al. 2001

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Four Holocene-long East Antarctic deuterium excess records are used to study past changes of the hydrological cycle in the Southern Hemisphere. We combine simple and complex isotopic models to quantify the relationships between Antarctic deuterium excess uctuations and the sea surface temperature (SST) integrated over the moisture source areas for Antarctic snow. The common deuterium excess increasing trend during the ®rst half of the Holocene is therefore interpreted in terms of a warming of the average ocean moisture source regions over this time. Available Southern Hemisphere SST records exhibit opposite trends at low latitudes (warming) and at high latitudes (cooling) during the Holocene. The agreement between the Antarctic deuterium excess and low-latitude SST trends supports the idea that the tropics dominate in providing moisture for Antarctic precipitation. The opposite trends in SSTs at low and high latitudes can potentially be explained by the decreasing obliquity during the Holocene inducing opposite trends in the local mean annual insolation between low and high latitudes. It also implies an increased latitudinal insolation gradient that in turn can maintain a stronger atmospheric circulation transporting more tropical moisture to Antarctica. This mechanism is supported by results from a mid-Holocene climate simulation performed using a coupled ocean-atmosphere model.

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“…Snow is transported by the wind before it is permanently added to the underlying snow cover. The snow cover at Dome C is therefore highly influenced by the wind (for example, Palais et al, 1982). A lot of effort has gone into describing the effect of the wind on the surface mass balance and the snow microstructure and stratigraphy (for example, Brun et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…During a traverse between Syowa Station and the South Pole, surface density was measured at several stakes and was never found to be less than 210 kg m −3 (Fujiwara and Endo, 1971). Palais et al (1982) made several 3 m snow profiles at Dome C and found a strong stratigraphic layering. Besides visible stratigraphy, gross β-radioactivity and microparticles were used to date the layers.…”

Section: Introductionmentioning

confidence: 99%

Event-driven deposition of snow on the Antarctic Plateau: analyzing field measurements with SNOWPACK

Zwaaftink

Cagnati²,

Crepaz³

et al. 2013

The Cryosphere

103

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Abstract. Antarctic surface snow has been studied by means of continuous measurements and observations over a period of 3 yr at Dome C. Snow observations include solid deposits in form of precipitation, diamond dust, or hoar, snow temperatures at several depths, records of deposition and erosion on the surface, and snow profiles. Together with meteorological data from automatic weather stations, this forms a unique dataset of snow conditions on the Antarctic Plateau. Large differences in snow amounts and density exist between solid deposits measured 1 m above the surface and deposition at the surface. We used the snow-cover model SNOWPACK to simulate the snow-cover evolution for different deposition parameterizations. The main adaptation of the model described here is a new event-driven deposition scheme. The scheme assumes that snow is added to the snow cover permanently only during periods of strong winds. This assumption followed from the comparison between observations of solid deposits and daily records of changes in snow height: solid deposits could be observed on tables 1 m above the surface on 94 out of 235 days (40 %) while deposition at the surface occurred on 59 days (25 %) during the same period, but both happened concurrently on 33 days (14 %) only. This confirms that precipitation is not necessarily the driving force behind non-temporary snow height changes. A comparison of simulated snow height to stake farm measurements over 3 yr showed that we underestimate the total accumulation by at least 33 %, when the total snow deposition is constrained by the measurements of solid deposits on tables 1 m above the surface. During shorter time periods, however, we may miss over 50 % of the deposited mass. This suggests that the solid deposits measured above the surface and used to drive the model, even though comparable to ECMWF forecasts in its total magnitude, should be seen as a lower boundary. As a result of the new deposition mechanism, we found a good agreement between model results and measurements of snow temperatures and recorded snow profiles. In spite of the underestimated deposition, the results thus suggest that we can obtain quite realistic simulations of the Antarctic snow cover by the introduction of event-driven snow deposition.

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Snow Stratigraphic Studies At Dome C, East Antarctica: An Investigation Of Depositional and Diagenetic Processes

Cited by 34 publications

References 1 publication

Orbital tuning chronology for the Vostok climate record supported by trapped gas composition

Orbital tuning chronology for the Vostok climate record supported by trapped gas composition

Holocene hydrological cycle changes in the Southern Hemisphere documented in East Antarctic deuterium excess records

Event-driven deposition of snow on the Antarctic Plateau: analyzing field measurements with SNOWPACK

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