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gerontocrat

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Greenland 2019-20 SMB (Snowfall & Melting) Year
« on: August 30, 2019, 02:33:13 PM »
I am starting this thread so these posts conform to the DMI Greenland Year September to August as in their website http://polarportal.dk/en/greenland/surface-conditions/.

Also, if I ever get to see new GRACE-FO data on overall Greenland Ice Sheet Mass this looks like a good place to put it.

The Greenland 2019 melting Season thread is staying open, as there will be many 2019 reports coming out to the end of the year and beyond.
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blumenkraft

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #1 on: August 30, 2019, 10:18:32 PM »
That naming will surely prevent weekly questions about the meaning of SMB. ;)
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #2 on: September 08, 2019, 01:57:40 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 7 September


MELT continues to fall in line with the average,

PRECIPITATION has been higher than average,

so as a result, in this first week of the new DMI Greenland year, SMB gain is above average
________________________________________________________________________
Quote from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
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P-maker

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #3 on: September 11, 2019, 07:35:59 AM »
Gerontocrat,

Thank you for keeping track of this. Please check the units and the numbers on your second graph. It sure seems like a lot ice per square km.

Thanks

Alexander555

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #4 on: September 11, 2019, 12:17:42 PM »
It's not that much. A ton is something close to 1 by 1 by 1 meter. A km2 is 1 million m2 . So a layer of 1 km2 and 1 meter thick is a million tons. That makes 7000 tons close to nothing.

nukefix

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #5 on: September 11, 2019, 12:21:30 PM »
1 gigaton of ice ~= 1km^3

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #6 on: September 11, 2019, 01:50:32 PM »
1 gigaton of ice ~= 1km^3

Late at night, I mixed up my gt, tons & '000s of tonnes when trying to do the analysis in a hurry.
That'll teach me..

So I am deleting the post and doing it again.

Damn & Blast, sorry all. Mea Culpa

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blumenkraft

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #7 on: September 11, 2019, 01:57:55 PM »
No worries, thanks for your great work! :)
“I’m an introvert. I’m just different that’s all. I’m so sorry. I don’t have a gun. I don’t do that stuff... All I was trying to do was to become better. I’ll do it... You all are phenomenal. You are beautiful. And I love you. Try to forgive me. I’m sorry.”

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Alexander555

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #8 on: September 11, 2019, 02:20:16 PM »
Are you sure it was wrong ? Normaly it can not be that much more than 7 mm a year. If i'm right the loss is from glaciers calving.

SteveMDFP

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #9 on: September 11, 2019, 02:35:38 PM »
1 gigaton of ice ~= 1km^3

Late at night, I mixed up my gt, tons & '000s of tonnes when trying to do the analysis in a hurry.
That'll teach me..

So I am deleting the post and doing it again.

Damn & Blast, sorry all. Mea Culpa

Well, what's a few orders of magnitude among friends?

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #10 on: September 11, 2019, 02:41:56 PM »
Try again...... Only got it wrong by a magnitude of 10^3
The per km2 calculations are now in million tons per km2, i.e. tons per m2. 1 ton per m2 equates to a water equivalent height change of 1 metre, or about 1.09 metres of solid freshwater ice.

_____________________________________________________________________
Apart from the DMI daily daily data, we have occasional papers such as this one....
https://www.pnas.org/content/116/19/9239
Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018

and hopefully GRACE-FO data on a monthly basis (still only up to May 2019).

There is of course, always a problem. The PNAS paper, which is incredibly good, and has a super spreadsheet to download, summarise the individual glacial sub-regions into 7 basins, as does  the GRACE-FO data. BUT, the boundaries are not quite the same. (see 1st image).

So the SMB, discharge and Net Mass Balance basin data in the PNAS paper cannot be matched simply to the GRACE-FO Net Mass Balance basin data. Scientists, bless 'em!
________________________________________________________________________
The PNAS paper analyses the Greenland ice sheet (GIS) mass balance change down to individual glacial basins and summarises the data into the 7 drainage basins.

I attach 2 graphs. One looks at cumulative ice mass loss by basin and in total, the other looks at mass change per km2.

The cumulative mass loss graph shows that
- the South West basin in recent years has switched from mass gain to mass loss,
- The North West and the South East are losing the greatest mass of ice,
- overall mass loss from 1972 to 2018 equivalent to nearly 14 mm of sea level rise,

The cumulative mass loss graph per KM2 shows that
- The North West (NW) and the South East (SE) are losing the greatest mass of ice per square kilometre by far,.
- average NW basin height loss 1972-2018 circa 5.5 metres (water equivalent),
- average SE basin height loss 1972-2018 circa 6.5 metres (water equivalent),
- overall GIS height loss 1972-2018 nearly 3 metres (water equivalent).

Of note also is that of the 260 sub-basins/glaciers in the PNAS data, in 1972 only about 35 were losing mass. In 2018, that figure is over 200. It is a different icesheet.

_______________________________________________________________________
I will be (I hope) working on comparing the PNAS data (which starts in 1972) with the GRACE-FO data from 2002. I also will be digging out the data on individual glaciers for posting on the threads for those glaciers.

Have I got it right this time?
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #11 on: September 11, 2019, 06:59:49 PM »
More data derived  from the PNAS paper  https://www.pnas.org/content/116/19/9239
Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018


I had a look at three individual glaciers mass loss from 1972 to 2018. The attached graph shows that the glaciers losing the most ice are not always the ones losing the most by area

e.g. JAKOBSHAVN_ISBRAE  has lost 100GT (335 GT) more ice than the 2nd highest, STEENSTRUP-DIETRICHSON (225 GT).

But when looked at as Million Tons per km2 (which equates to a water equivalent  loss in height in metres), the JAKOBSHAVN_ISBRAE loss is 4.3 MT per Km2, while the STEENSTRUP-DIETRICHSON loss is 23.4.

So while JAKOBSHAVN_ISBRAE is number 1 in total ice mass loss, on the per Km2 measure it is at No 130 out of 260, compared with STEENSTRUP at No. 2 and No. 32.

The PETERMANN_GLETSCHER has lost 56 GT, but due to its large size this is only 0.75 million tons per km2, making it 32nd highest it total mass loss, and no 200 out of 260 in loss per km2.

I.e. looking at only the cumulative mass loss of a glacier is not a good guide to intensity of its decay. Mass loss per unit of area matters more.
_____________________________________________________
Pure Speculation:-
The area calculated by the PNAS paper of the ice sheet is 1.81 million km2.
The area of the ice sheet quoted most often is 1.71 million km2

My speculation is that in 1972, that was the area of the ice sheet, suggesting in the nearly 50 years since, the ice sheet has retreated by 100,000 km2.

This is not a small area, and means that for at least part of the year, the energy from insolation is not being used for melting ice, but for heating the land, which quickly releases the heat to the atmosphere. This is a positive feedback? It must be happening to some extent, (e.g. the OK glacier in Iceland is now bare land for a good part of the year)

Of course, this 100,000 km2 might just be the result of problems in getting accurate data for 260 sub-regions of Greenland.

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Alexander555

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #12 on: September 11, 2019, 07:11:00 PM »
I see it now, it's cumulative mass loss. So the worst part, the green line. Lost 500 000 ton between Jan 2016 and Dec 2018. That's like 25 cm a year.
« Last Edit: September 11, 2019, 07:18:22 PM by Alexander555 »

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #13 on: September 23, 2019, 02:27:36 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 22 September


MELT continues to fall in line with the average to almost zero

PRECIPITATION  From now until spring next year, the story is only about snowfall, which has been up and own like a yo-yo so far. .

So as a result, in this first weeks of the new DMI Greenland year, SMB gain is around average
________________________________________________________________________
Quote from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
__________________________________________
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #14 on: September 24, 2019, 01:29:06 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 23 September

Warm & wet in Greenland..

MELT in the last 2 days refused to fall in line with the average to zero by the end of the month.

PRECIPITATION  From now until spring next year, the story is only about snowfall, which has been up and own like a yo-yo so far. . and in the last 2 days very high indeed

So as a result, in this first weeks of the new DMI Greenland year, SMB gain is around average with a blip up in the last 2 days.
________________________________________________________________________
Quote from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
__________________________________________
[/quote]
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Stephan

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #15 on: September 24, 2019, 07:44:36 PM »
The webcam on Freya Gletscher is working again.
Gerontocrat wrote "warm and wet", which is obviously true. New snow in the higher altitudes, and temperatures are now again slightly above melting (-12,4°C Sep20, -7,1°C Sep21, -2,8°C Sep22 and +1,2°C Sep23)
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #16 on: September 26, 2019, 12:03:32 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 25 September

Warm & wet in Greenland..

The Melting Season is refusing to die. High +ve temperature anomalies might keep it going to the end of the month.

PRECIPITATION It has been wet - but maybe not so much for the next few days.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
__________________________________________
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #17 on: September 29, 2019, 01:53:20 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 28 September

Warm & wet in Greenland..

Melt a tiny bit of melt

plus

PRECIPITATION very very low.

gives

SMB with an unusual though very small loss on this day.

Looks like Greenland will be very dry for the next few days with high +ve temp anomalies. Just might see very low SMB gains and even a loss or two.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
__________________________________________
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #18 on: September 30, 2019, 12:16:55 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 29 September

Melt a tiny bit of melt - almost zero

but

PRECIPITATION Greenland "drizabone"

gives

SMB with a 2nd unusual though very small loss on this day.

Looks like Greenland will be very dry for the next few days with high +ve temp anomalies. Just might see very low SMB gains and even a loss or two.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
__________________________________________
[/quote]
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Stephan

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #19 on: September 30, 2019, 02:26:28 PM »
News from Freya Webcam (1.053 m above sea level)
Three days ago temperature rose to +6.5°C. Rain had melted away all the snow. Then some snow fell again on Sep 28, but now the sky is bright and the sun - although much less powerful than in summer - managed to melt away most of it on the southern side of the mountains.

See attached photo
Link to this webcam: https://www.foto-webcam.eu/webcam/freya1/
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #20 on: September 30, 2019, 09:35:55 PM »
Hullo Stephan

What a beautiful photo - such clarity.
Given the weather outlook might be some more chances.

Do we know what webcams are operating on Greenland?
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oren

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #21 on: October 01, 2019, 02:37:06 AM »
Not many, a few listed in this link:
http://banquisaenelartico.blogspot.com/p/groenlandia.html
Including at Summit and at EastGRIP, a couple of others, and a second webcam at Freya.

More Arctic webcams in this link but no additional ones in Greenland itself:
http://banquisaenelartico.blogspot.com/p/webcams.html

There used to be the Hotel Arctic webcam (Ilulissat Ice fjord) but it seems to gone and the link is dead:
http://hotelarctic.com/om_hotel_arctic/webcam/

And the Helheim Glacier webcam also appears to be offline, maybe Espen knows more:
http://glacierresearch.com/locations/helheim/realtime-images-terminus.html

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #22 on: October 04, 2019, 02:31:17 PM »
SE Greenland has been getting a lot of precipitation, from the "back end" of lows.

I wonder how much is falling as rain, and how much as snow.
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #23 on: October 07, 2019, 09:15:20 PM »
When I named this thread I forgot to add to the title - Discharge and Mass Loss.

GRACE-FO are producing monthly data for Greenland and Antarctic Ice Sheet Mass Change (i.e. SMB less calving and melt from ocean water)

Germany is the best source - links....
http://gravis.gfz-potsdam.de/greenland
http://gravis.gfz-potsdam.de/antarctica
Nice maps and graphs

& Data @.....
ftp://isdcftp.gfz-potsdam.de/grace/GravIS/GFZ/Level-3/ICE/GIS
ftp://isdcftp.gfz-potsdam.de/grace/GravIS/GFZ/Level-3/ICE/AIS

Greenland in the 30 days Mid-June to Mid-July 2019 lost 210 GT of ice,  N.B. before the major melt event in late July early August.

The Raw Data graph also shows SMB going up and then down hugely in 2016
- data problems as the GRACE satellite showed its age, or was there a really big snowfall followed by major melt?
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #24 on: October 10, 2019, 01:16:42 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 9 October 2019

Accumulated Data 1 Sept to 9 October

Melt Very little and from now of zero consequence until next April

but

PRECIPITATION up & down like a yo-yo and slightly above average

gives

SMB slightly above average
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
__________________________________________
[/quote]
[/quote]
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #25 on: October 19, 2019, 01:22:16 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 9 October 2019

Accumulated Data 1 Sept to 18 October

Melt Very little and from now of zero consequence until next April

but

PRECIPITATION up & down like a yo-yo and at average

gives

SMB  gain is average. But this disguises the East - West Greenland contrast, below average SMB gain in the West, above average SMB gain in the East, especially the SE.

The Baffin Sea also has well above average SSTs. Perhaps this will keep calving and glacier melt at the ocean edge above average (not included in SMB data.  (S= Surface)).
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
__________________________________________
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Stephan

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #26 on: October 20, 2019, 10:45:27 AM »
An update from Freya Gletscher, E Greenland:
It has become quite cold. The sky is clear, but the valley with the glacier in it does not receive any sun beams, because the sun is already too low.
In that part of Greenland there are only a few cm of snow in the higher altitudes.
See attached photo.
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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #27 on: October 20, 2019, 11:49:21 AM »
News from Freya Webcam (1.053 m above sea level)
Three days ago temperature rose to +6.5°C. Rain had melted away all the snow. Then some snow fell again on Sep 28, but now the sky is bright and the sun - although much less powerful than in summer - managed to melt away most of it on the southern side of the mountains.

See attached photo
Link to this webcam: https://www.foto-webcam.eu/webcam/freya1/
Lovely photo again, Stephan.

Seem to be a lot of live webcams to be found from .... https://www.webcams.travel/popular/greenland

Here is one from Nuuk Harbour - not a lot of ice. When does winter come?
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #28 on: October 26, 2019, 08:33:57 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 25 October 2019


Nothing of consequence to report .... posted to remind myself to keep the thread alive.

Accumulated Data 1 Sept to 25 October

Melt Very little and from now of zero consequence until next April

but

PRECIPITATION up & down like a yo-yo and overall average

gives

SMB at average - with the usual less than average on the west and above average in the East (especially SE)
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
__________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
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Stephan

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #29 on: October 26, 2019, 08:55:22 PM »
Nothing new from Freya Gletscher Webcam too - apart from a temperature rise from -18.7°C (22 Oct) to -2.9°C (26 Oct). Not much snow, and it looks like sunset, but it is noon!

PS: Freya Webcam seems to have problems (once again). There are only around 10 days of pictures available for this month so far.
Link: https://www.foto-webcam.eu/webcam/freya1/
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #30 on: November 05, 2019, 12:13:47 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 4 November 2019


Nothing of consequence to report .... posted to remind myself to keep the thread alive.

Accumulated Data 1 Sept to 4 November

Melt From now of zero consequence until next April

but

PRECIPITATION up & down like a yo-yo and overall average or a bit below.

gives

SMB slightly below average - with the usual less than average on the west and above average in the East (especially SE), plus a unusual above average SMB area in he NW corner.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #31 on: November 12, 2019, 01:09:56 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 11 November 2019


Nothing of consequence to report .... posted to remind myself to keep the thread alive.

Accumulated Data 1 Sept to 11 November

Melt From now of zero consequence until next April

but

PRECIPITATION up & down like a yo-yo and back to overall average due to days of high snowfall in the South East.

gives

SMB close to average - with the usual much less than average on the west and much above average in the East (especially SE), and a blob of above average SMB in the NW.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_________________________________________
[/quote]
"Para a Causa do Povo a Luta Continua!"
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Darvince

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #32 on: November 16, 2019, 11:11:40 PM »
Strong and widespread storm dumping snow on Greenland right now...

http://polarportal.dk/fileadmin/polarportal/surface/SMB_combine_SM_day_EN_20191115.png

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #33 on: November 17, 2019, 01:07:32 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 16 November 2019

As Darvince posted, quite a dump of snow Nov 14 & 15 - highest this season so far.

Accumulated Data 1 Sept to 16 November

Melt From now of zero consequence until next April

but

PRECIPITATION up & down like a yo-yo and back to overall average due to days of high snowfall mostly in the South East.

But the latest snow dump means

SMB above average - with the usual much less than average on the west and much above average in the East (especially SE), and a blob of above average SMB in the NW.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_________________________________________
[/quote]
[/quote]
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #34 on: November 28, 2019, 09:06:18 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 27 November 2019


How average can you get?

Accumulated Data 1 Sept to 27 November

Melt From now of zero consequence until next April

and

PRECIPITATION up & down like a yo-yo as usual, result.....

SMB at average - with the average much less than average on the west and the average much above average in the East (especially SE), and a blob of above average SMB in the NW.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_______________________________________________________________--
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #35 on: December 05, 2019, 07:31:34 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 4 December 2019


Accumulated Data 1 Sept to 4 December

Melt From now of zero consequence until next April, but today a bit of sublimation in the SE

and

PRECIPITATION up & down like a yo-yo as usual, and i the last few day very much up - result.....

SMB abovt average - with the average much less than average on the west and the average much above average in the East (especially SE), and a the blob of above average SMB in the **NW becoming more substantial.

**Might be something to do with open water above average in Baffin Bay reaching as far as the Nares strait along the West coast.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_______________________________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #36 on: December 10, 2019, 11:21:38 PM »
Greenland is melting faster..

https://www.bbc.co.uk/news/science-environment-48387030
Climate change: Greenland ice melt 'is accelerating'
Quote
Greenland is losing ice seven times faster than it was in the 1990s. The assessment comes from an international team of polar scientists who've reviewed all the satellite observations over a 26-year period.

They say Greenland's contribution to sea-level rise is currently tracking what had been regarded as a pessimistic projection of the future.

It means an additional 7cm of ocean rise could now be expected by the end of the century from Greenland alone. "Storms, if they happen against a baseline of higher seas - they will break flood defences," said Prof Andy Shepherd, of Leeds University. "The simple formula is that around the planet, six million people are brought into a flooding situation for every centimetre of sea-level rise. So, when you hear about a centimetre rise, it does have impacts," he told BBC News.

Greenland is reacting to the Arctic's rapid warming. This is a part of the globe that has seen a 0.75C temperature rise in just the past decade.

https://www.nature.com/articles/s41586-019-1855-2  Paywalled
Quote
Abstract
In recent decades, the Greenland Ice Sheet has been a major contributor to global sea-level rise1,2, and it is expected to be so in the future3. Although increases in glacier flow4–6 and surface melting7–9 have been driven by oceanic10–12 and atmospheric13,14 warming, the degree and trajectory of today’s imbalance remain uncertain. Here we compare and combine 26 individual satellite measurements of changes in the ice sheet’s volume, flow and gravitational potential to produce a reconciled estimate of its mass balance. Although the ice sheet was close to a state of balance in the 1990s, annual losses have risen since then, peaking at 335 ± 62 billion tonnes per year in 2011. In all, Greenland lost 3,800 ± 339 billion tonnes of ice between 1992 and 2018, causing the mean sea level to rise by 10.6 ± 0.9 millimetres. Using three regional climate models, we show that reduced surface mass balance has driven 1,971 ± 555 billion tonnes (52%) of the ice loss owing to increased meltwater runoff. The remaining 1,827 ± 538 billion tonnes (48%) of ice loss was due to increased glacier discharge, which rose from 41 ± 37 billion tonnes per year in the 1990s to 87 ± 25 billion tonnes per year since then. Between 2013 and 2017, the total rate of ice loss slowed to 217 ± 32 billion tonnes per year, on average, as atmospheric circulation favoured cooler conditions15 and as ocean temperatures fell at the terminus of Jakobshavn Isbræ16. Cumulative ice losses from Greenland as a whole have been close to the IPCC’s predicted rates for their high-end climate warming scenario17, which forecast an additional 50 to 120 millimetres of global sea-level rise by 2100 when compared to their central estimate.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #37 on: December 20, 2019, 02:43:59 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 19 December 2019


Accumulated Data 1 Sept to 19 December

Melt From now of zero consequence until next April, but today a bit of sublimation in the SE

and

PRECIPITATION up & down like a yo-yo as usual, and in the last few day very much down, on this day more or less zero - result.....

SMB a bit below average - with the average much less than average on the west and the average much above average in the East (especially SE), and a the blob of above average SMB in the NW

ps: No monthly update of GRACE-FO data yet - very late arriving
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_______________________________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #38 on: December 27, 2019, 11:40:53 AM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 26 December 2019


Accumulated Data 1 Sept to 19 December

Melt From now of zero consequence probably until next April.

and

PRECIPITATION over the last week or so mostly well below average - result.....

SMB below average - with the average much above average in the coastal South East and the coastal NW. Elsewhere average of below average, well below average in coastal valleys.

ps: No monthly update of GRACE-FO data yet - very very late.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_______________________________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #39 on: January 13, 2020, 01:52:46 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 12 January 2020


Accumulated Data 1 Sept 2019 to 12 January 2020

Melt From now of zero consequence probably until next April.

and

PRECIPITATION over the last 2 weeks or so more below than above average - result.....

SMB below average - with the average much above average in the coastal SE, NE, & NW. Elsewhere average or below average, well below average in coastal valleys.

ps: No monthly update of GRACE-FO data yet - very very (2 months) late.
________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_______________________________________________________________
[/quote]
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #40 on: January 18, 2020, 03:32:36 AM »
After over 2 months, new data from GRACE-FO - at last.

Updated GRACE-FO ice mass fromftp://isdcftp.gfz-potsdam.de/grace/GravIS/GFZ/Level-3/ICE/GIS

Last measurement date mid-November 2019.
12 month ice mass loss 479 GT, i.e. 1.32 mm sea level rise.

Note the precipitous loss in ice sheet mass in the south/central coast of West Greenland (basin 306) since around 2017.

The lower than average snowfall over the last month or so might show an uptick in the 12 month change in ice sheet mass in the next month or two.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #41 on: February 01, 2020, 08:00:28 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 31January 2020


Accumulated Data 1 Sept 2019 to 31 January 2020

Melt From now of zero consequence probably until next April.

and

PRECIPITATION over the last 2 weeks or so a bit more below than above average - result.....

SMB below average - with the average much above average in the coastal SE, NE, & NW. Elsewhere average or below average.

________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_______________________________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #42 on: February 18, 2020, 06:10:59 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 17 February 2020


Accumulated Data 1 Sept 2019 to 17 February 2020

Melt From now of zero consequence probably until next April.

and

PRECIPITATION over the last 2 weeks or so a bit around average - result.....

SMB below average - with the average much above average in the coastal SE, NE, & NW. Elsewhere average or below average.

________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_______________________________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #43 on: February 18, 2020, 08:12:15 PM »
After exactly one month, new data from GRACE-FO
Updated GRACE-FO ice mass fromftp://isdcftp.gfz-potsdam.de/grace/GravIS/GFZ/Level-3/ICE/GIS

Last measurement date mid-December 2019.
12 month ice mass loss 480 GT, i.e. 1.33 mm sea level rise.

Note the precipitous loss in ice sheet mass in the south/central coast of West Greenland (basin 306) since around 2017.

In the last month a net increase of 22GT in Greenland Ice Mass, perhaps a bit less than the increase in SMB for that month. So maybe glacial melt was continuing at the coastal fringe.

I so so wish DMI would give numerical data on SMB change, because they have it, updated daily.
"Para a Causa do Povo a Luta Continua!"
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FrostKing70

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #44 on: February 24, 2020, 06:01:20 PM »
It is early in the year, but I am concerned about the trend line:

http://polarportal.dk/en/greenland/surface-conditions/

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #45 on: February 27, 2020, 11:21:14 PM »
http://polarportal.dk/en/greenland/surface-conditions/ as at 27 February 2020


Accumulated Data 1 Sept 2019 to 27 February 2020

Melt From now of zero consequence probably until next April.

and

PRECIPITATION the recent drought in snowfall continues - result.....

SMB well below average - with the average much above average in the coastal SE, NE, & NW. Elsewhere average or well below average.

________________________________________________________________________
Quotes from DMI
Quote
The Greenland Ice Sheet evolves throughout the year as weather conditions change. Precipitation increases the mass of the ice sheet, whilst greater warmth leads to melting, which causes it to lose mass. The term surface mass balance (SMB) is used to describe the isolated gain and loss of mass of the surface of the ice sheet – excluding the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Melting does not in itself necessarily give rise to mass loss, however. Much of the meltwater will refreeze in the surface snow layers rather than running off the ice sheet, and this process is included in the calculations of surface mass balance which is why the melt area plot may differ from the areas of negative mass balance seen on the map “Daily change”. Likewise, sublimation does not count as melting and surface mass balance can therefore occur with the surface temperature being far below the melting point.
_______________________________________________________________
[/quote]
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

FrostKing70

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #46 on: March 02, 2020, 09:29:49 PM »
I have a question that I do not know how to find the answer to, hoping some one here can point me in the correct direction!

At what elevation would we expect all of the snow from a given winter to melt and then run off the Greenland Ice Sheet?  In other words, at what elevation would we expect the ice sheet to no longer gain mass in a given year?

In my mental model, I am expecting the southwestern side of the GIS to melt first, and reach a point where the melting accelerates as the elevation gets lower and lower.

regards
FK

FrostKing70

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #47 on: March 02, 2020, 09:33:02 PM »
For the visual people (like me!), what is the elevation of the "white band" around the center of the GIS which represents no mass gain or loss?

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #48 on: March 02, 2020, 09:38:26 PM »

Tor Bejnar

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #49 on: March 02, 2020, 10:27:34 PM »
Here's a topo map from here approximately overlain on the Loss-Gain map you provided.  The elevation varies widely (under 2000 m. in SE to 3000 m. in the E)!
Arctic ice is healthy for children and other living things.