The variability of surface radiation fluxes over landfast sea ice near Zhongshan station, east Antarctica during austral spring

Abstract The surface spectral albedo was measured over coastal landfast sea ice in Prydz Bay (off Zhongshan Station), East Antarctica from 5 October to 26 November of 2016. The mean albedo decreased from late-spring to early-summer, mainly responding to the change in surface conditions from dry (phase I) to wet (phase II). The evolution of the albedo was strongly influenced by the surface conditions, with alternation of frequent snowfall events and katabatic wind that induce snow blowing at the surface. The two phases and day-to-day albedo variability were more pronounced in the near-infrared albedo wavelengths than in the visible ones, as the near-infrared photons are more sensitive to snow metamorphism, and to changes in the uppermost millimeters and water content of the surface. The albedo diurnal cycle during clear sky conditions was asymmetric with respect to noon, decreasing from morning to evening over full and patchy snow cover, and decreasing more rapidly in the morning over bare ice. We conclude that snow and ice metamorphism and surface melting dominated over the solar elevation angle dependency in shaping the albedo evolution. However, we realize that more detailed surface observations are needed to clarify and quantify the role of the various surface processes.

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Sea ice-related halogen enrichment at Law Dome, coastal East Antarctica

10.5194/cp-2016-74 ◽

2016 ◽

Cited By ~ 1

Author(s):

Paul Vallelonga ◽

Niccolo Maffezzoli ◽

Andrew D. Moy ◽

Mark A. J. Curran ◽

Tessa R. Vance ◽

...

Keyword(s):

Sea Ice ◽

20Th Century ◽

East Antarctica ◽

Austral Spring ◽

High Accumulation ◽

Low Levels ◽

The Law ◽

Western Side ◽

The Antarctic ◽

Firn Core

Abstract. The Law Dome site is ideal for the evaluation of sea ice proxies due to its location near to the Antarctic coast, regular and high accumulation throughout the year, an absence of surface melting or remobilization, and minimal multiyear sea ice. We present records of bromine and iodine concentrations and their enrichment beyond seawater compositions, arguing that halogen enrichment is indicative of the local sea ice area, particularly the 90–110° E sector of the Wilkes coast. Our findings support the results of previous studies of sea ice variability from Law Dome, indicating that Wilkes coast sea ice area is currently at its lowest level since the start of the 20th century. From the Law Dome DSS1213 firn core, 26 years of monthly deposition data indicate that the period of peak bromine enrichment is during Austral spring-summer, from November to February. Results from a traverse along the lee (Western) side of Law Dome show low levels of sodium and bromine deposition, with the greatest fluxes in the vicinity of the Law Dome summit. Finally, iodine enrichment is well correlated to that of bromine, indicating a common, sea ice source for their enrichment.

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Modelling landfast sea ice and its influence on ocean-ice interactions in the area of the Totten Glacier, East Antarctica

10.5194/egusphere-egu21-8846 ◽

2021 ◽

Author(s):

Guillian Van Achter ◽

Thierry Fichefet ◽

Hugues Goosse ◽

Charles Pelletier ◽

Jean Sterlin ◽

...

Keyword(s):

Sea Ice ◽

Climate Models ◽

Mixed Layer Depth ◽

Global Climate Models ◽

East Antarctica ◽

Ice Shelf ◽

Sea Ice Extent ◽

Coastal Polynya ◽

Landfast Sea Ice ◽

The Impact

The Totten Glacier in East Antarctica is of major climate interest because of the large fluctuation of its grounding line and of its potential vulnerability to climate change. The ocean above the continental shelf in front of the Totten ice shelf exhibits large extents of landfast sea ice with low interannual variability. Landfast sea ice is mostly not or sole crudely represented in current climate models. These models are potentially omitting or misrepresenting important effects related to this type of sea ice, such as its influence on coastal polynya locations. Yet, the impact of the landfast sea ice on the ocean &#8211; ice shelf interactions is poorly understood. Using a series of high-resolution, regional NEMO-LIM-based experiments including an explicit treatment of ocean &#8211; ice shelf interactions over the years 2001-2010, we simulate a realistic landfast sea ice extent in the area of Totten Glacier through a combination of a sea ice tensile strength parameterisation and a grounded iceberg representation. We show that the presence of landfast sea ice impacts seriously both the location of coastal polynyas and the ocean mixed layer depth along the coast, in addition to favouring the intrusion of mixed Circumpolar Deep Water into the ice shelf cavities. Depending on the local bathymetry and the landfast sea ice distribution, landfast sea ice affects ice shelf cavities in different ways, either by increasing the ice melt (+28% for the Moscow University ice shelf) or by reducing its seasonal cycle (+10% in March-May for the Totten ice shelf). This highlights the importance of including an accurate landfast sea ice representation in regional and eventually global climate models

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Observation and thermodynamic modeling of the influence of snow cover on landfast sea ice thickness in Prydz Bay, East Antarctica

10.5194/egusphere-egu2020-1715 ◽

2020 ◽

Author(s):

Jiechen Zhao ◽

Bin Cheng ◽

Timo Vihma ◽

Qinghua Yang ◽

Fengming Hui ◽

...

Keyword(s):

Sea Ice ◽

Snow Cover ◽

Annual Cycle ◽

Snow Depth ◽

Snow Accumulation ◽

East Antarctica ◽

Prydz Bay ◽

Ice Thickness ◽

Sea Ice Thickness ◽

Landfast Sea Ice

The observed snow depth and ice thickness on landfast sea ice in Prydz Bay, East Antarctica, were used to determine the role of snow in (a) the annual cycle of sea ice thickness at a fixed location (SIP) where snow usually blows away after snowfall and (b) early summer sea ice thickness within the transportation route surveys (TRS) domain farther from coast, where annual snow accumulation is substantial. The annual mean snow depth and maximum ice thickness had a negative relationship (r = &#8722;0.58, p < 0.05) at SIP, indicating a primary insulation effect of snow on ice thickness. However, in the TRS domain, this effect was negligible because snow contributes to ice thickness. A one-dimensional thermodynamic sea ice model, forced by local weather observations, reproduced the annual cycle of ice thickness at SIP well. During the freeze season, the modeled maximum difference of ice thickness using different snowfall scenarios ranged from 0.53&#8211;0.61 m. Snow cover delayed ice surface and ice bottom melting by 45 and 24 days, respectively. The modeled snow ice and superimposed ice accounted for 4&#8211;23% and 5&#8211;8% of the total maximum ice thickness on an annual basis in the case of initial ice thickness ranging from 0.05&#8211;2 m, respectively.

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Observation and thermodynamic modeling of the influence of snow cover on landfast sea ice thickness in Prydz Bay, East Antarctica

Cold Regions Science and Technology ◽

10.1016/j.coldregions.2019.102869 ◽

2019 ◽

Vol 168 ◽

pp. 102869 ◽

Cited By ~ 1

Author(s):

Jiechen Zhao ◽

Bin Cheng ◽

Timo Vihma ◽

Qinghua Yang ◽

Fengming Hui ◽

...

Keyword(s):

Sea Ice ◽

Snow Cover ◽

Thermodynamic Modeling ◽

East Antarctica ◽

Prydz Bay ◽

Ice Thickness ◽

Sea Ice Thickness ◽

Landfast Sea Ice

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Annual cycle of landfast sea ice in Prydz Bay, east Antarctica

Journal of Geophysical Research Atmospheres ◽

10.1029/2008jc005223 ◽

2010 ◽

Vol 115 (C2) ◽

Cited By ~ 35

Author(s):

Ruibo Lei ◽

Zhijun Li ◽

Bin Cheng ◽

Zhanhai Zhang ◽

Petra Heil

Keyword(s):

Sea Ice ◽

Annual Cycle ◽

East Antarctica ◽

Prydz Bay ◽

Landfast Sea Ice

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Glacial and tidal strain of landfast sea ice in Terra Nova Bay, East Antarctica, observed by interferometric SAR techniques

Remote Sensing of Environment ◽

10.1016/j.rse.2018.02.033 ◽

2018 ◽

Vol 209 ◽

pp. 41-51 ◽

Cited By ~ 3

Author(s):

Hyangsun Han ◽

Hoonyol Lee

Keyword(s):

Sea Ice ◽

East Antarctica ◽

Terra Nova Bay ◽

Terra Nova ◽

Landfast Sea Ice ◽

Interferometric Sar

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Simultaneous disintegration of outlet glaciers in Porpoise Bay (Wilkes Land), East Antarctica, driven by sea ice break-up

The Cryosphere ◽

10.5194/tc-11-427-2017 ◽

2017 ◽

Vol 11 (1) ◽

pp. 427-442 ◽

Cited By ~ 25

Author(s):

Bertie W. J. Miles ◽

Chris R. Stokes ◽

Stewart S. R. Jamieson

Keyword(s):

Sea Ice ◽

East Antarctica ◽

High Temporal Resolution ◽

Ice Flow ◽

Envisat Asar ◽

Glacier Terminus ◽

Wilkes Land ◽

Break Up ◽

Atmospheric Circulation Anomalies ◽

Landfast Sea Ice

Abstract. The floating ice shelves and glacier tongues which fringe the Antarctic continent are important because they help buttress ice flow from the ice sheet interior. Dynamic feedbacks associated with glacier calving have the potential to reduce buttressing and subsequently increase ice flow into the ocean. However, there are few high temporal resolution studies on glacier calving, especially in East Antarctica. Here we use ENVISAT ASAR wide swath mode imagery to investigate monthly glacier terminus change across six marine-terminating outlet glaciers in Porpoise Bay (76° S, 128° E), Wilkes Land (East Antarctica), between November 2002 and March 2012. This reveals a large near-simultaneous calving event in January 2007, resulting in a total of ∼  2900 km2 of ice being removed from glacier tongues. We also observe the start of a similar large near-simultaneous calving event in March 2016. Our observations suggest that both of these large calving events are driven by the break-up of the multi-year sea ice which usually occupies Porpoise Bay. However, these break-up events appear to have been driven by contrasting mechanisms. We link the 2007 sea ice break-up to atmospheric circulation anomalies in December 2005 weakening the multi-year sea ice through a combination of surface melt and a change in wind direction prior to its eventual break-up in January 2007. In contrast, the 2016 break-up event is linked to the terminus of Holmes (West) Glacier pushing the multi-year sea ice further into the open ocean, making the sea ice more vulnerable to break-up. In the context of predicted future warming and the sensitivity of sea ice to changes in climate, our results highlight the importance of interactions between landfast sea ice and glacier tongue stability in East Antarctica.

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