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Author Topic: EAIS Contributions to SLR by 2100  (Read 62688 times)


AbruptSLR

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Re: EAIS Contributions to SLR by 2100
« Reply #151 on: December 16, 2016, 09:30:43 PM »
observations re Totten glacier


For those of you who hesitate to click on links, I provide the following information; which helps to quantify the extent of recent ocean-ice interaction with the Totten Ice Shelf.

Stephen Rich Rintoul, Alessandro Silvano,  Beatriz Pena-Molino,  Esmee van Wijk,  Mark Rosenberg,  Jamin Stevens Greenbaum and Donald D. Blankenship (16 Dec 2016), "Ocean heat drives rapid basal melt of the Totten Ice Shelf", Science Advances, Vol. 2, no. 12, e1601610, DOI: 10.1126/sciadv.1601610

http://advances.sciencemag.org/content/2/12/e1601610

Abstract: "Mass loss from the West Antarctic ice shelves and glaciers has been linked to basal melt by ocean heat flux. The Totten Ice Shelf in East Antarctica, which buttresses a marine-based ice sheet with a volume equivalent to at least 3.5 m of global sea-level rise, also experiences rapid basal melt, but the role of ocean forcing was not known because of a lack of observations near the ice shelf. Observations from the Totten calving front confirm that (0.22 ± 0.07) × 106 m3 s−1 of warm water enters the cavity through a newly discovered deep channel. The ocean heat transport into the cavity is sufficient to support the large basal melt rates inferred from glaciological observations. Change in ocean heat flux is a plausible physical mechanism to explain past and projected changes in this sector of the East Antarctic Ice Sheet and its contribution to sea level."
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georged

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Re: EAIS Contributions to SLR by 2100
« Reply #152 on: December 17, 2016, 12:18:43 PM »

Observations from the Totten calving front confirm that (0.22 ± 0.07) × 106 m3 s−1 of warm water enters the cavity through a newly discovered deep channel.


If my math is right, that's 220,000 cumec/s. Which is equivalent to 1000 of this: http://www.greatlaketaupo.com/things-to-do/must-do/huka-falls/

AbruptSLR

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Re: EAIS Contributions to SLR by 2100
« Reply #153 on: December 17, 2016, 04:38:55 PM »
The linked article is entitled: "East Antarctica is Melting From Above and Below".

http://www.climatecentral.org/news/east-antarctica-melting-climate-change-20986

Extract: "East Antarctica is remote even by Antarctic standards. Harsh winds and ocean currents have largely cut off the region from the rest of the world.

That’s left its massive stores of ice largely intact, especially compared to West Antarctica where a massive meltdown is underway that could raise seas by 10 or more feet in the coming centuries. But as carbon pollution warms the air and the ocean, there are signs that the region’s stability is under threat. Two new studies of different ice shelves — tongues of ice that essentially act as bathtub plugs — have seen major melting that could portend a less stable future for the region."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: EAIS Contributions to SLR by 2100
« Reply #154 on: January 03, 2017, 06:28:08 PM »

The linked reference is entitled: "Validation of satellite altimetry by kinematic GNSS in central East Antarctica", and it discusses how radar altimetry was used to improve the accuracy of ice-surface elevations in the central East Antarctica area.

Schröder, L., Richter, A., Fedorov, D. V., Eberlein, L., Brovkov, E. V., Popov, S. V., Knöfel, C., Horwath, M., Dietrich, R., Matveev, A. Y., Scheinert, M., and Lukin, V.: Validation of satellite altimetry by kinematic GNSS in central East Antarctica, The Cryosphere Discuss., doi:10.5194/tc-2016-282, in review, 2017.

http://www.the-cryosphere-discuss.net/tc-2016-282/

Abstract. Ice-surface elevation profiles of more than 30.000 km in total length are derived from kinematic GNSS observations on sledge convoy vehicles along traverses between Vostok station and the East Antarctic coast. The profiles have accuracies between 4 and 9 cm. They are used to validate elevation datasets from both radar and laser satellite altimetry as well as four digital elevation models. A crossover analysis with three different Envisat radar altimetry datasets yields a clear preference for the relocation method over the direct method of slope correction and for threshold retrackers over functional fit algorithms. The validation of Cryosat-2 low-resolution mode and SARIn mode datasets documents the progress made from baseline B to C elevation products. ICESat laser altimetry data are demonstrated to be accurate to a few decimeters over wide range of surface slopes. A crossover adjustment above subglacial Lake Vostok combining ICESat elevation data with our GNSS profiles yields a new set of ICESat laser campaign biases and provides new, independent evidence for the stability of the ice-surface elevation above the lake. The evaluation of digital elevation models reveals the importance of radar altimetry for the reduction of interpolation errors.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: EAIS Contributions to SLR by 2100
« Reply #155 on: January 16, 2017, 06:11:38 PM »
The linked article is entitled: "Epic Antarctic voyage maps seafloor to predict ocean rise as glacier the size of California melts".  It will be interesting to eventually read about what the research team finds-out about the long-term melting patterns for Totten.

https://www.theguardian.com/world/2017/jan/15/totten-glacier-antarctic-voyage-to-map-seafloor-hobart-invstigator

Extract: "In East Antarctica, 3,000km south of the West Australian town of Albany, an ice shelf the size of California is melting from below.

The concerning trend was confirmed by Australian scientists in December, who reported that warming ocean temperatures were causing the rapid melt of the end of the Totten glacier, which is holding back enough ice to create a global sea rise of between 3.5 metres and six metres.

On Saturday, a team of international scientists left Hobart aboard the Australian research ship Investigator to map the seafloor ahead of the glacier to trace its history back to the last ice age, in the hopes of predicting its future melting patterns."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

solartim27

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Re: EAIS Contributions to SLR by 2100
« Reply #156 on: January 21, 2017, 05:12:10 AM »
This post got me thinking of Amery, and I found an old Sentinel from Nov 2015 to compare. 
Some calving of the Amery ice shelf in Prydz Bay, near the 'loose tooth'.

Not the best match for the gif, I tried to align the blue masking layer, darker image is 2017.   The big rift change makes me think we may be getting another huge berg floating about soon (it's all relative, 2018 or 19 time frame?).
http://www.polarview.aq/images/105_S1jpgfull/S1B_EW_GRDM_1SSH_20170115T151915_FB58_S_1.final.jpg (62 MB)

S1A_EW_GRDM_1SSH_20151109T152805_82F0_S_1.final.jpg
FNORD

AbruptSLR

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Re: EAIS Contributions to SLR by 2100
« Reply #157 on: January 23, 2017, 07:39:44 PM »
The linked reference indicates that East Antarctic ice shelves are more vulnerable than previously thought, with continued anthropogenic global warming:
 
Martin Siegert (2017), "Glaciology: Vulnerable Antarctic ice shelves", Nature Climate Change, Volume: 7, Pages: 11–12, doi:10.1038/nclimate3189

http://www.nature.com/nclimate/journal/v7/n1/full/nclimate3189.html

Summary: "The decay of floating ice shelves around Antarctica speeds up ice flow from the continent and contributes to increased sea-level rise. Now, meltwater attributed to warm winds has been discovered on an East Antarctic ice shelf, suggesting greater vulnerability than previously thought."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson