Antarctic blue ice areas - towards extracting palaeoclimate information

Sinisalo, Anna; Moore, John C.

doi:10.1017/s0954102009990691

Cited by 52 publications

(67 citation statements)

References 82 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This makes BIAs an ideal location to obtain "horizontal ice cores" -that is, collecting samples for analysis along a shallow surface trench rather than traditional deep drilling -which may contain a record of climate record spanning the Holocene and perhaps longer (Moore et al, 2006;Sinisalo and Moore, 2010). Presently, however, the problems in dating and interpreting climate records from horizontal ice cores have largely precluded their usefulness as climate archives (Sinisalo and Moore, 2010). Chief among these difficulties is an understanding of the long-term stability of the blue ice as the surrounding ice sheet changes through a glacial cycle.…”

Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

“…However the complex geometry, usually including large ice thickness variations along the blue ice field, suggests that a three-dimensional, higher order or full-Stokes model is needed to produce realistic ice flow simulations. Scharffenbergbotnen is the best-studied BIA with a long history of observations including ice depth, surface velocities, mass balance, ice dating, ice temperature measurements, and both vertical and horizontal ice core archives of ice chemistry and water isotopes (the data sets are summarized in Sinisalo and Moore, 2010). Hence this BIA is a suitable test bed for numerical simulation using advanced flow modeling, which could provide insights on the dynamical evolution of the region since the last glacial.…”

Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

“…2). The middle part of this ice core was dated to 4426 ± 215 calendar years BP (Sinisalo and Moore, 2010). A longer horizontal core (2.7 km) was collected in 2006/07 (the complete blue line in Fig.…”

Section: Study Area: Heimefrontfjella Scharffenbergbotnenmentioning

confidence: 99%

See 2 more Smart Citations

Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area

et al. 2014

View full text Add to dashboard Cite

Abstract. We use a full-Stokes thermo-mechanically coupled ice-flow model to study the dynamics of the glacier inside Scharffenbergbotnen valley, Dronning Maud Land, Antarctica. The domain encompasses a high accumulation rate region and, downstream, a sublimation-dominated bare ice ablation area. The ablation ice area is notable for having old ice at its surface since the vertical velocity is upwards, and horizontal velocities are almost stagnant there. We compare the model simulation with field observations of velocities and the age distribution of the surface ice. No satisfactory match using an isotropic flow law could be found because of too high vertical velocities and much too high horizontal ones in simulations despite varying enhancement factor, geothermal heat flux and surface temperatures over large ranges. However, the existence of a pronounced ice fabric may explain the observed present-day surface velocity and mass balance distribution in the inner Scharffenbergbotnen blue ice area. Near absence of data on the temporal evolution of Scharffenbergbotnen since the Late Glacial Maximum necessitates exploration of the impact of anisotropy using prescribed ice fabrics: isotropic, single maximum, and linear variation with depth, in both two-dimensional and threedimensional flow models. The realistic velocity field simulated with a noncollinear orthotropic flow law, however, produced surface ages in significant disagreement with the few reliable age measurements and suggests that the age field is not in a steady state and that the present distribution is a result of a flow reorganization at about 15 000 yr BP. In order to fully understand the surface age distribution, a transient simulation starting from the Late Glacial Maximum including the correct initial conditions for geometry, age, fabric and temperature distribution would be needed. This is the first time that the importance of anisotropy has been demonstrated in the ice dynamics of a blue ice area and demonstrates the need to understand ice flow in order to better interpret archives of ancient ice for paleoclimate research.

show abstract

Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

Section: Published By Copernicus Publications On Behalf Of the Europementioning

confidence: 99%

See 1 more Smart Citation

Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Petrenko et al, 2006Petrenko et al, , 2009. Blue ice areas, where ancient ice is brought to the surface by ice flow, and especially continental ice margins have been recognized as valuable, inexpensive archives of paleo-climate information, which are not encumbered by sample size restrictions (Sinisalo and Moore, 2010;Petrenko, 2013).…”

Section: Introductionmentioning

confidence: 99%

Atmospheric gas records from Taylor Glacier, Antarctica, reveal ancient ice with ages spanning the entire last glacial cycle

et al. 2017

View full text Add to dashboard Cite

Abstract.Old ice for paleo-environmental studies, traditionally accessed through deep core drilling on domes and ridges on the large ice sheets, can also be retrieved at the surface from ice sheet margins and blue ice areas. The practically unlimited amount of ice available at these sites satisfies a need in the community for studies of trace components requiring large sample volumes. For margin sites to be useful as ancient ice archives, the ice stratigraphy needs to be understood and age models need to be established. We present measurements of trapped gases in ice from Taylor Glacier, Antarctica, to date the ice and assess the completeness of the stratigraphic section. Using δ 18 O of O 2 and methane concentrations, we unambiguously identify ice from the last glacial cycle, covering every climate interval from the early Holocene to the penultimate interglacial. A high-resolution transect reveals the last deglaciation and the Last Glacial Maximum (LGM) in detail. We observe large-scale deformation in the form of folding, but individual stratigraphic layers do not appear to have undergone irregular thinning. Rather, it appears that the entire LGM-deglaciation sequence has been transported from the interior of the ice sheet to the surface of Taylor Glacier relatively undisturbed. We present an age model that builds the foundation for gas studies on Taylor Glacier. A comparison with the Taylor Dome ice core confirms that the section we studied on Taylor Glacier is better suited for paleo-climate reconstructions of the LGM due to higher accumulation rates.

show abstract

“…In blue-ice areas (BIAs), however, no firn layer exists and glacier ice is exposed at the surface (Bintanja, 1999;Sinisalo and Moore, 2010). Various observational and model studies show that 0.8-1.6% of the AIS surface can be classified as a BIA (e.g.…”

Section: Introductionmentioning

confidence: 99%

On the formation of blue ice on Byrd Glacier, Antarctica

Ligtenberg¹,

Lenaerts²,

Broeke³

et al. 2014

J. Glaciol.

View full text Add to dashboard Cite

ABSTRACT. Blue-ice areas (BIAs) cover $1% of the East Antarctic ice sheet and are visual evidence of persistent ablation. In these regions, more snow is sublimated and/or eroded than is accumulated. The physical processes driving the formation of BIAs are poorly understood. Here we combine a firndensification model with high-resolution (5.5 km) maps of surface mass balance and ice velocity to simulate the build-up and removal of a firn layer along an ice flowline passing Byrd Glacier. A BIA is formed once the complete firn layer is removed. Feedback processes, which enhance blue-ice formation through the difference in surface characteristics of snow and ice, are examined using sensitivity simulations. The presence of blue ice on Byrd Glacier is found to be mainly determined by (1) ice velocity, (2) surface mass balance and (3) the characteristics (thickness, mass) of the firn layer prior to entering the ablation area. With a moderate decrease of the surface mass balance, the location and extent of the simulated BIA on Byrd Glacier is found to be in good qualitative agreement with MODIS optical imagery.

show abstract

Antarctic blue ice areas - towards extracting palaeoclimate information

Cited by 52 publications

References 82 publications

Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area

Influence of anisotropy on velocity and age distribution at Scharffenbergbotnen blue ice area

Atmospheric gas records from Taylor Glacier, Antarctica, reveal ancient ice with ages spanning the entire last glacial cycle

On the formation of blue ice on Byrd Glacier, Antarctica

Contact Info

Product

Resources

About