Greenland - What Do We Know, What Is The Long Term Future And Is There Any Evidence Of A Melt Out?

[knocker]

Jason Box â€@climate_ice 3h3 hours ago

wet weather and rain speeds Greenland... I contributed climatology/meteorology to a new article out in

 

@NatureGeosci 

 

http://sciencenordic.com/heavy-summer-rain-greenland-speeds-ice-melt â€¦

[knocker]

Modern solar maximum forced late 20^th century Greenland cooling

 

The abrupt Northern Hemispheric (NH) warming at the end of the 20^th century has been attributed to an enhanced greenhouse effect. Yet, Greenland and surrounding subpolar North Atlantic remained anomalously cold in 1970s- early 1990s. Here, we reconstructed robust Greenland temperature records (NGRIP and GISP2) over the past 2100 years using argon and nitrogen isotopes in air trapped within ice cores, and show that this cold anomaly was part of a recursive pattern of antiphase Greenland temperature responses to solar variability with a possible multidecadal lag. We hypothesize that high solar activity during the modern solar maximum (ca. 1950s-1980s) resulted in a cooling over Greenland and surrounding subpolar North Atlantic through the slow-down of Atlantic Meridional Overturning Circulation (AMOC) with atmospheric feedback processes.

 

http://onlinelibrary.wiley.com/doi/10.1002/2015GL064764/full?campaign=wlytk-41855.5282060185

 

Synopsis

 

http://news.agu.org/press-release/suns-activity-controls-greenland-temperatures/

 

Also from Jason Box

 

Worked on this study: Climate scientists find another reason for faster Greenland meltdown

 

Amplified melt and flow of the Greenland icesheet driven by late-summer cyclonic rainfall

 

 

Intense rainfall events significantly affect Alpine and Alaskan glaciers through enhanced melting, ice-flow acceleration

and subglacial sediment erosion, yet their impact on the Greenland ice sheet has not been assessed. Here we present

measurements of ice velocity, subglacial water pressure and meteorological variables from the western margin of the

Greenland ice sheet during a week of warm, wet cyclonic weather in late August and early September 2011. We find that

extreme surface runoff from melt and rainfall led to a widespread acceleration in ice flow that extended 140 km into the

ice-sheet interior. We suggest that the late-season timing was critical in promoting rapid runoff across an extensive bare ice

surface that overwhelmed a subglacial hydrological system in transition to a less-efficient winter mode. Reanalysis data reveal

that similar cyclonic weather conditions prevailed across southern and western Greenland during this time, and we observe

a corresponding ice-flow response at all land- and marine-terminating glaciers in these regions for which data are available.

Given that the advection of warm, moist air masses and rainfall over Greenland is expected to become more frequent in the

coming decades, our findings portend a previously unforeseen vulnerability of the Greenland ice sheet to climate change

 

http://www.nature.com/articles/ngeo2482.epdf?referrer_access_token=jGeTVjjn1pANDha6n3NFU9RgN0jAjWel9jnR3ZoTv0N4A4pKJktVLNTbr8j198gD2ZdPpnp4rCF-lqPb2NxoG3-UgYS2WgeS0lQaRVHsaN_iytcyHC1vt3oTmyaRo5aV_IwJe1AxjIDh7JRrHEeKSIIHA70NO4XbzMFeklM7tju3zLKr-xt8Tz768DbfBpW5McFi727Y3GDtoTLoI1mjWSVFHFiCZknMYhEKk9_vISGj7pLckKPBJWf_LuDevaz0pQwm8S0Gsh-N5XLbWdRfIJcJCTKMM6dyh50IhEwsRIk%3D&tracking_referrer=www.washingtonpost.com

Edited July 16, 2015 by knocker

[knocker]

Summer heat hits cold ice sheet

 

Warm conditions arrived on the Greenland Ice Sheet in late June, causing a sudden spike in melting that increased in early July and led to a sharp reduction in surface albedo (brightness of the snow). However, as of mid-July surface melt remained less extensive than during 2012, the record melt summer.

[knocker]

High melt rates this week really show in accumulated curve. Ice sheet making up for lost time

http://polarportal.dk/en/groenlands-indlandsis/nbsp/isens-overflade/

Edited July 18, 2015 by knocker

[knocker]

 

Greenland Ice Sheet “Thermal-Viscous Collapseâ€

 

We have a new study in the AGU open access journal Earth’s Future this month, which introduces the notion of thermal-viscous collapse of the Greenland ice sheet¹. While people tend to think of ice as a solid, it is actually a non-Newtonian fluid, because it deforms and flows over longer time-scales. Of the many strange material properties of ice, the non-linear temperature dependence of its viscosity is especially notable; ice at 0 °C deforms almost ten times more than ice at -10 °C at the same stress. This temperature-dependent viscosity makes ice flow very sensitive to ice temperature. We know that the extra meltwater now being produced at the surface of the Greenland ice sheet, relative to 50 or 100 years ago, contains tremendous latent heat energy. So, in the study, we set out to see if the latent heat in future extra meltwater might have a significant impact on future ice sheet form and flow.

 

[Gray-Wolf]

So if Solar max protected Greenland what will the supposed slow down of solar output bring??..........

[knocker]

Petermann Glacier Tidal Heaving

 

Some glaciers float on the ocean around Antarctica and Greenland. Petermann Gletscher in North Greenland is one of these. It spawned massive Manhattan-sized ice islands in 2010 and 2012. Could tides influence when and where such break-ups occur? After all, the tides under the floating glacier move the ice up and down. But how does a 50 km long, 15 km wide, and 300 m thick floating glacier pivots about its “hinge?†Does it do so like a rigid plate of steel or does it bend and buckle like jelly? I do not know, because nobody has measured the tidal motions of Petermann’s floating ice. So, one of many projects this summer will be to measure tides on Petermann with fancy GPS systems.

 

http://icyseas.org/2015/07/20/petermann-glacier-tidal-heaving/

[knocker]

Jason Box â€@climate_ice Aug 3

July, when most melting happens in Greenland, had the 2nd lowest reflectivity on record, tied with 2011

 

[stewfox]

Surface melt season now looks like coming to a end in Greenland

 

A interesting summer for sure

 

 

[Gael_Force]

Surface melt season now looks like coming to a end in Greenland

 

A interesting summer for sure

This big melt has been mooted as enhancing the cold pool in the Atlantic; I wonder if we'll see a relaxing of the anomaly or has the fresh water caused a disruption to the overturning that will be more permanent?

[BornFromTheVoid]

Surface melt season now looks like coming to a end in Greenland

 

A interesting summer for sure

 

Probably best not to get ahead of yourself Stew, don't forget your comments last month.

 

 

And now its on the way down as the brief melt season comes to an end

 

We often see the 'refreeze'  start by mid July in Greenland.

 

[knocker]

The spectacular glaciated summit plateau of Saunders Island in NW Greenland surrounded by sea ice

Image NASA

Edited August 9, 2015 by knocker

[stewfox]

 

Probably best not to get ahead of yourself Stew, don't forget your comments last month.

 

 

The melt always drops of dramatically post mid July as it did this year, given the plateau height

 

If we go above 2sd during the rest if the summer ill eat my hat.

[knocker]

Nasa’s Oceans Melting Greenland study will deploy 200 robot probes to measure the full extent of Arctic climate change

 

 

An urgent attempt to study the rate at which Greenland’s mighty ice sheets are melting has been launched by Nasa. The aim of the six-year project, called Oceans Melting Greenland (OMG), is to understand how fast the world’s warming seas are now eroding the edges of the island’s vast icecaps. Warming air temperatures are already causing considerable glacier loss there, but the factors involving the sea that laps the bases of its great ice masses, and which is also heating up, are less well understood.

 

http://www.theguardian.com/environment/2015/aug/09/omg-nasa-project-oceans-melting-greenland?utm_source=Daily+Carbon+Briefing&utm_campaign=9364e396b8-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-9364e396b8-303447709

[keithlucky]

The melt always drops of dramatically post mid July as it did this year, given the plateau height

 

If we go above 2sd during the rest if the summer ill eat my hat.

Green land refreeze has started http://beta.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

Edited August 10, 2015 by keithlucky

[knocker]

Wow that's some calving event.

 

Jakobshavn record retreat

http://neven1.typepad.com/blog/2015/08/jakobshavn-record-retreat.html

Edited August 17, 2015 by knocker

[knocker]

Greenland melt analysis

 

http://nsidc.org/greenland-today/2015/08/cornering-the-heat-on-the-ice-sheet/

 

[stewfox]

Green land refreeze has started http://beta.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

 

In need we are seeing a rapid re freeze of surface melt and any melting left is now more then 2 SD below normal, an amazing turn around. The melt season was very short this year , with a short peak.

Edited August 23, 2015 by stewfox

[knocker]

It's not obvious to me how short, cryptic posts can add anything to the more in depth NSIDC analysis posted above unless they are disagreeing with the latter. The NSIDC report seems perfectly clear to me.

 

Although perhaps an albedo update which has rocketed back to normal after a dark July.

 

Edited August 23, 2015 by knocker

[knocker]

A few people may still not be aware of the rate of mass loss from Greenland Ice Sheet from NASA gravity satellites

 

https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CD8QFjAFahUKEwjGx6Ghk8DHAhUDaxQKHfJlBnw&url=http%3A%2F%2Fcongrexprojects.com%2Fdocs%2F12c20_docs2%2F2-grace_esa-clic_forsberg.pdf%3Fsfvrsn%3D2&ei=WjvaVcayGYPWUfLLmeAH&usg=AFQjCNG20oalSh-UjadcT6GzBEBcafuOSQ&sig2=J7JsypCHD5VCXq57-J5HvA&cad=rja

[Methuselah]

I counted no less than ELEVEN recoveries on that graph, Malc!

[stewfox]

It's not obvious to me how short, cryptic posts can add anything to the more in depth NSIDC analysis posted above unless they are disagreeing with the latter. The NSIDC report seems perfectly clear to me.

 

Although perhaps an albedo update which has rocketed back to normal after a dark July.

 

Its the surface melt figures for Greenland for the year. The graphs speak for themselves and have been discussed all summer. I'm sure it belongs in the Greenland melt out thread.

[knocker]

Of course it belongs in the Greenland thread but I just thought your 'The melt season was very short this year , with a short peak' could have been qualified with 'Surface melting was significantly more frequent and more extensive than average on the Greenland Ice Sheet in July, especially around the northwestern coast'. Otherwise, heaven forbid, people might gain the false impression you were trying to put some spin on it.

[knocker]

What massive Greenland iceberg calving looks like from the air

 

http://jasonbox.net/what-massive-greenland-iceberg-calving-looks-like-from-the-air/ â€¦

 

 

[knocker]

Guest post: The state of the Greenland ice sheet in 2015

A guest post from climate scientists Dr Ruth Mottram and Dr Peter Langen from the Danish Meteorological Institute.

 

http://www.carbonbrief.org/blog/2015/09/guest-post-the-state-of-the-greenland-ice-sheet-in-2015/?utm_source=Daily+Carbon+Briefing&utm_campaign=24fe6aac6d-cb_daily&utm_medium=email&utm_term=0_876aab4fd7-24fe6aac6d-303447709

Edited September 7, 2015 by knocker