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PhillipS

Greenland Melt Discussion

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Looks as if melt is below average to start August, and should remain that way with cold air pooling over Greenland. Might get a brief spike from WAA as the low from the Beaufort approaches, but then a strong high pressure with -10C 850s settles over the ice sheet, keeping it cold...GFS shows 2m temps of -20C in the higher elevations atop Greenland. 

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Doesn't look like it got higher than low 50s. Obviously still a huge melt from mid June to late July, though.

What a turnaround for Greenland from June/July. Huge dropoff in melt. How does this August compare to previous years?

Yes, a huge turnaround. We went from way above average melt to average/ very slightly below average melt. His call of 55 - 65% looked pretty good to me based on melt percentage, it's not like he busted. I'm not sure what the point of your posts were.

The story of 2015 Greenland melt will be the highly anomolous melt in June/July. It won't be the near average melt that followed.

post-2727-0-20958700-1439249565_thumb.jp

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Yes, a huge turnaround. We went from way above average melt to average/ very slightly below average melt. His call of 55 - 65% looked pretty good to me based on melt percentage, it's not like he busted. I'm not sure what the point of your posts were.

The story of 2015 Greenland melt will be the highly anomolous melt in June/July. It won't be the near average melt that followed.

attachicon.gifimage.jpg

 

Looks like we briefly flirted with 55%. Regardless, any comparison to 2012 has been shut down in August. It's no longer even close. Three weeks ago, this was looking like it would be the second greatest melt year after 2012...not so sure about that now.

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If I was hunting for busts, it would have been this. ;)

 

Since the SMB is only one component of the GIS net mass balance, and not even the biggest component, it's a bit early to declare it a bust.  The DMI calculates the GIS melt season as Sept through August, and typically DMI posts a melt season summary late in the year that combines all factors.  Here is the current accumulated SMB

 

SMB_curves_LA_EN_20150809.png

 

In my estimation, 2015 will be a net 275 - 325 km3 mass loss for the GIS, well below the record in 2012 of around 400 km3.

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Since the SMB is only one component of the GIS net mass balance, and not even the biggest component, it's a bit early to declare it a bust.  The DMI calculates the GIS melt season as Sept through August, and typically DMI posts a melt season summary late in the year that combines all factors.  Here is the current accumulated SMB.

 

 

In my estimation, 2015 will be a net 275 - 325 km3 mass loss for the GIS, well below the record in 2012 of around 400 km3.

 

The statement was about strong melt in August with strong -NAO. That hasn't been the case. Still a lot of month, though.

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Greenland looks to get real cold in the next week...18z GFS shows -20C 850s atop the ice sheet at 180 hours. First sighting of the -20C isotherm in a few months:

 

attachicon.gifgreenland-20.gif

The deep freeze is coming. Greenland is about to be in the grasp of the long, cold, and dark winter season. I love this time of year as the cold builds, snow falls and summer retreats.

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Talk of a record calving event on Jacobsen recently. Would like to know more, obviously there is more than meets the eye in regards to the 2015 melt season.

 

Here is a comment on the recent Jakobshavn glacier at Nevins.  

 

And a Washington Post article that includes quotes from Jason Box and Richard Alley

 

And last, but certainly not least, is the NASA Earth Observatory post.

 

There is a lot of uncertainty in the estimates of the size of the calving event, but this size of event will have a big impact on the net mass balance analysis for the 2015 melt season.  Many estimates put it at around 125  12.5 km2 in area, so if the glacier is 1,000 meters thick at the calving site, that would mean a loss of roughly 125  12.5 Gtons of mass in four days.  And the calving goes on all year, unlike the surface melt.

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Here is a comment on the recent Jakobshavn glacier at Nevins.  

 

And a Washington Post article that includes quotes from Jason Box and Richard Alley

 

And last, but certainly not least, is the NASA Earth Observatory post.

 

There is a lot of uncertainty in the estimates of the size of the calving event, but this size of event will have a big impact on the net mass balance analysis for the 2015 melt season.  Many estimates put it at around 125 km2 in area, so if the glacier is 1,000 meters thick at the calving site, that would mean a loss of roughly 125 Gtons of mass in four days.  And the calving goes on all year, unlike the surface melt.

 

Nevins blog corrected their initial estimate to 12.5km2 down an order of magnitude from the original. Still a very significant event. With the calving, the glacier has retreated roughly 600m since last years max retreat (max retreat is usually in September) indicating that net mass losses continue in the glacier drainage.

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Greenland saw a steep, but brief, resurgence of surface melting

 

greenland_melt_area_plot_tmb.png

 

DMI shows the 2014 -2015 GIS melt season (which runs Sept through Aug) as being about 75 gigatons below the long term average, and about 250 gigatons above the record surface melt in 2011 - 2012.  

 

SMB_curves_LA_EN_20150901.png

 

So it was a strong, but not exceptional GIS surface melt season.  The overall net mass balance hasn't been announced yet - but with recent large calving events reported I would estimate a net mass loss for 2015 of between 300 and 400 gigatons.

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The freeze level over Southern GIS is currently at 2750M. Over Eastern GIS 3050M.

That's freaking unbelievable.

Lance MODIS shows vigorous melting is underway over the snow covered land areas along both sides upwards of 70N.

And surface snow melt well into the interior upwards of 2000M along the SW side but way up there going from the S side to about 64N then NE from there.

It's likely we see snow cover again over these areas but if we don't or only see very little it will have resulted in major preconditioning.

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http://polarportal.dk/en/nyheder/arkiv/nyheder/usaedvanlig-tidlig-afsmeltning-i-groenland/

 

Unusually Early Greenland Melt

By Ruth Mottram, DMI
April 12th 2016

 

An early melt event over the Greenland ice sheet occurred this week, smashing by a month the previous records of more than 10% of the ice sheet melting.

Based on observation-initialized weather model runs by DMI, almost  12% of the Greenland ice sheet had more than 1mm of melt on Monday 11th April, following an early start to melting the previous day. Scientists at DMI were at first incredulous due to the early date. “We had to check that our models were still working properly” said Peter Langen, a climate scientist at DMI. “Fortunately we could see from the PROMICE.dk stations on the ice sheet that it had been well above melting, even above 10 °C. This helped to explain the results”.   The former top 3 earliest dates for a melt area larger than 10% were previously all in May (5th May 2010, 8th May 1990, 8th May 2006).

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