scholarly journals The growth of sublimation crystals and surface hoar on the Antarctic plateau

2014 ◽  
Vol 8 (4) ◽  
pp. 1205-1215 ◽  
Author(s):  
J.-C. Gallet ◽  
F. Domine ◽  
J. Savarino ◽  
M. Dumont ◽  
E. Brun
Keyword(s):  
Energy Budget ◽  
Temperature Drop ◽  
Snow Surface ◽  
Surface Mass ◽  
Antarctic Plateau ◽  
Time Variations ◽  
Sunny Weather ◽  
Frost Flowers ◽  
Snow Model ◽  
The Antarctic

Abstract. On the Antarctic plateau, precipitation quantities are so low that the surface mass budget is for an important part determined by exchanges of water vapor between the snow surface and the atmosphere surface. At Dome C (75° S, 123° E), we have frequently observed the growth of crystals on the snow surface under calm sunny weather. Here we present the time variations of specific surface area (SSA) and density of these crystals. Using the detailed snow model Crocus, we conclude that the formation of these crystals was very likely due to the nighttime formation of surface hoar crystals and to the daytime formation of sublimation crystals. These latter crystals form by processes similar to those involved in the formation of frost flowers on young sea ice. The formation of these crystals impacts the albedo, mass and energy budget of the Antarctic plateau. In particular, the SSA variations of the surface layer can induce an instantaneous forcing at the snow surface up to −10 W m−2 at noon, resulting in a surface temperature drop of 0.45 K. This result confirms that snow SSA is a crucial variable to consider in the energy budget and climate of snow-covered surfaces.

scholarly journals The growth of sublimation crystals and surface hoar on the Antarctic plateau

2013 ◽  
Vol 7 (6) ◽  
pp. 5971-5999
Author(s):  
J.-C. Gallet ◽  
F. Domine ◽  
J. Savarino ◽  
M. Dumont ◽  
E. Brun
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Temperature Drop ◽  
Antarctic Plateau ◽  
Snow Crystal ◽  
Time Variations ◽  
Frost Flowers ◽  
Snow Model ◽  
The Antarctic

Abstract. On the Antarctic plateau, the budget of water vapor and energy is in part determined by precipitation, but these are so low that the dynamic of snow crystal growth and sublimation at the surface can be important factors. At Dome C (75° S, 123° E), we have frequently observed the growth of crystals on the snow surface under calm sunny weather. Here, we present the time variations of specific surface area and density of these crystals. Using the detailed snow model Crocus, we conclude that these crystals were very likely due to the nighttime formation of surface hoar crystals and to the daytime formation of sublimation crystals. These latter crystals form by processes similar to those involved in the formation of frost flowers on young sea ice. The formation of these crystals impact the albedo, mass and energy budget of the Antarctic plateau. In particular, the specific surface area variations of the surface layer can induce an instantaneous forcing of up to −10 W m−2 at noon, resulting in a surface temperature drop of 0.45 K.

scholarly journals The Heat and Mass Balance of Snow Dunes on the Central Antarctic Plateau

1969 ◽  
Vol 8 (53) ◽  
pp. 277-284 ◽  
Author(s):  
G. Weller
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Heat Balance ◽  
Snow Surface ◽  
Accumulation Pattern ◽  
Antarctic Plateau ◽  
The Antarctic ◽  
The Heat Balance

The heat-balance components of the faces of snow blocks were measured at “Plateau” station on the Antarctic plateau using micro-meteorological instrumentation. Heat-balance considerations and sublimation observations indicate considerable mass loss from the sloping snow surfaces during summer but little loss from horizontal surfaces. This process tends to level the irregularities of the snow surface. The conclusions are applicable to the snow dunes forming the general accumulation pattern on the Antarctic plateau.

scholarly journals Do climate models underestimate snow accumulation on the Antarctic plateau? A re-evaluation of/from in situ observations in East Wilkes and Victoria Lands

2009 ◽  
Vol 50 (50) ◽  
pp. 61-65 ◽  
Author(s):  
C. Genthon ◽  
O. Magand ◽  
G. Krinner ◽  
M. Fily
Keyword(s):  
Climate Models ◽  
Snow Accumulation ◽  
Surface Mass ◽  
Antarctic Plateau ◽  
Clear Sky ◽  
Quality Control Criteria ◽  
The Cost ◽  
Control Criteria ◽  
The Antarctic

AbstractIt has been suggested that meteorological and climate models underestimate snow accumulation on the Antarctic plateau, because accumulation (or surface mass balance (SMB)) is dominated by clear-sky precipitation while this process is not properly taken into account in the models. Here, we show that differences between model and field SMB data are much reduced when the in situ SMB reports used to evaluate the models are filtered through quality-control criteria and less reliable reports are subsequently left out. We thus argue that, although not necessarily unsupported, model biases and their interpretations in terms of clear-sky vs synoptic precipitation on the Antarctic plateau may have been overstated in the past. To avoid such misleading issues, it is important that in situ SMB reports of insufficient or unassessed reliability are discarded, even at the cost of a strong reduction in spatial sampling and coverage.

scholarly journals Long-Term Snow Height Variations in Antarctica from GNSS Interferometric Reflectometry

2021 ◽  
Vol 13 (6) ◽  
pp. 1164
Author(s):  
Elisa Pinat ◽  
Pascale Defraigne ◽  
Nicolas Bergeot ◽  
Jean-Marie Chevalier ◽  
Bruno Bertrand
Keyword(s):  
Ice Sheet ◽  
Snow Accumulation ◽  
Surface Elevation ◽  
Snow Surface ◽  
Antarctic Ice Sheet ◽  
West Antarctic Ice Sheet ◽  
Surface Mass ◽  
West Antarctic ◽  
The Antarctic

Acquiring reliable estimates of the Antarctic Ice Sheet surface mass balance is essential for trustworthy predictions of its evolution and future contribution to sea level rise. Snow height variations, i.e., the net change of the surface elevation resulting from a combination of surface processes such as snowfall, ablation, and wind redistribution, can provide a unique tool to constrain the uncertainty on mass budget estimations. In this study, GNSS Interferometric Reflectometry (GNSS-IR) is exploited to assess the long-term variations of snow accumulation and ablation processes. Eight antennas belonging to the Polar Earth Observing Network (POLENET) network are considered, together with the ROB1 antenna, deployed in the east part of Antarctica by the Royal Observatory of Belgium. For ROB1, which is located on an ice rise, we highlight an annual variation of snow accumulation in April–May (~30–50 cm) and ablation during spring/summer period. A snow surface elevation velocity of +0.08 ± 0.01 ma−1 is observed in the 2013–2016 period, statistically rejecting the “no trend” null hypothesis. As the POLENET stations are all located on moving glaciers, their associated downhill motion must be corrected for using an elevation model. This induces an increased uncertainty on the snow surface elevation change determined from GNSS-IR. Among the eight stations analyzed, only three of them show a long-term snow height variation larger than the uncertainties. One is located on the Flask Galcier in the Antarctic Peninsula, with a decrease of more than 4 m between 2012 and 2014, with an uncertainty of 2.5 m. The second one is located on the Lower Thwaites Glacier where we observe, between 2010 and 2020, a snow surface drop of 10 m, with a conservative uncertainty of 1 m. The third station, located on the West Antarctic Ice Sheet (WAIS) divide, shows on the opposite an upward motion from 2005 to 2019, of 1.2 m with an uncertainty of 0.4 m. The snow surface change of the other POLENET stations analyzed is smaller than the uncertainty associated with the glacier slope.

scholarly journals The Heat and Mass Balance of Snow Dunes on the Central Antarctic Plateau

1969 ◽  
Vol 8 (53) ◽  
pp. 277-284 ◽  
Author(s):  
G. Weller
Keyword(s):  
Mass Loss ◽  
Mass Balance ◽  
Heat Balance ◽  
Snow Surface ◽  
Accumulation Pattern ◽  
Antarctic Plateau ◽  
The Antarctic ◽  
The Heat Balance

The heat-balance components of the faces of snow blocks were measured at “Plateau” station on the Antarctic plateau using micro-meteorological instrumentation. Heat-balance considerations and sublimation observations indicate considerable mass loss from the sloping snow surfaces during summer but little loss from horizontal surfaces. This process tends to level the irregularities of the snow surface. The conclusions are applicable to the snow dunes forming the general accumulation pattern on the Antarctic plateau.

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