Arctic Sea Ice : Forum

Cryosphere => Greenland and Arctic Circle => Topic started by: gerontocrat on August 30, 2019, 02:33:13 PM

Title: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: blumenkraft on August 30, 2019, 10:18:32 PM
That naming will surely prevent weekly questions about the meaning of SMB. ;)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: P-maker 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
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Alexander555 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: nukefix on September 11, 2019, 12:21:30 PM
1 gigaton of ice ~= 1km^3
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: blumenkraft on September 11, 2019, 01:57:55 PM
No worries, thanks for your great work! :)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Alexander555 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: SteveMDFP 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?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.

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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?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Alexander555 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
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Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Stephan 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)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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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Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
__________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Stephan 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/
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on October 01, 2019, 02:37:06 AM
Not many, a few listed in this link:
http://banquisaenelartico.blogspot.com/p/groenlandia.html (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 (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/ (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 (http://glacierresearch.com/locations/helheim/realtime-images-terminus.html)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
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[/quote]
[/quote]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
__________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Stephan 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
__________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Stephan 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/
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
_________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Darvince 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
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
_______________________________________________________________--
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
_______________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
_______________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
_______________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
_______________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
_______________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 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/
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat 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]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 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
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 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?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 on March 02, 2020, 09:38:26 PM
Apparently, this is called the "equilibrium line":

https://arctic.noaa.gov/Report-Card/Report-Card-2016/ArtMID/5022/ArticleID/277/Greenland-Ice-Sheet

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Tor Bejnar on March 02, 2020, 10:27:34 PM
Here's a topo map from here  (https://www.flickr.com/photos/66103993@N00/130597590) approximately overlain on the Loss-Gain map you provided.  The elevation varies widely (under 2000 m. in SE to 3000 m. in the E)!
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 on March 02, 2020, 11:24:13 PM
Thank you, that was very helpful!   

As I look at the overlay, it appears the equilibrium line on the south side is close to the 1,500 meters mentioned in the article, and climbs upward the farther north we go on the ice sheet. 

Makes perfect sense now that I see it, but I was not mentally adjusting for how long the GIS is from south to north and the associated temperature and isolation differences!
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on March 03, 2020, 07:00:25 AM
Nice work Tor.
I would have thought the equilibrium elevation would be lower. You learn something new every day.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: sidd on March 03, 2020, 08:08:17 AM
I keep careful watch on the saddle at 67N between north and south domes. When ELA consistently exceeds that, saddle collapse has begun. We are very close.

sidd
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on March 11, 2020, 07:35:29 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 10 March 2020


Accumulated Data 1 Sept 2019 to 10 March 2020

Melt From now of zero consequence probably until next April.

and

PRECIPITATION Snowfall tending a bit more below than above average- result.....

SMB continues well below average, over 50 GT , circa 15% less than average

SMB 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]
[/quote]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: grixm on March 15, 2020, 11:32:35 AM
The Freya glacier webcam is back up and the sun has started to come out. There's not that much snow, either.

https://www.foto-webcam.eu/webcam/freya1/

PS: Is this thread just for SMB data? If so, there is no general 2020 greenland season thread yet.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on March 15, 2020, 12:45:28 PM

PS: Is this thread just for SMB data? If so, there is no general 2020 Greenland season thread yet.
Due to being in a hurry I forgot to add in the title GRACE-FO Greenland Ice Sheet (GIS) Mass Loss.
But this is where I post the GIS monthly data from the GRACE-FO project.

You are correct, there are a large number of threads about different specialised aspects of Greenland, but not a general thread.

But keep those images coming, please - makes the thread more interesting and a sunny day now means melt.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Stephan on March 16, 2020, 10:13:43 PM
grixm,
thank you for posting the Freya webcam picture. It was off-line for quite a while now, so I didn't notice it is working again.
I invite all of you to visit that website. You can easily play around and look at the situation in the previous years (2019 it was off). In my opinion the March 2020 snow is much less than in the year 2018 and less than in 2017 and 2016 (different position of the webcam).
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on March 17, 2020, 11:43:14 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 16 March 2020


Accumulated Data 1 Sept 2019 to 16 March 2020

Melt Not long until April - when will the first day of -ve SMB gain be?

and

PRECIPITATION Snowfall very much below average in the last week- result.....

SMB continues well below average, maybe 75 GT , circa 20% less than average

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

Dry days also mean sunny days - surface melt tends to reduce albedo of snow, though not enough melt yet for run-off?
________________________________________________________________________
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]
[/quote]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on March 21, 2020, 08:19:03 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 20 March 2020


Accumulated Data 1 Sept 2019 to 20 March 2020

Melt Not long until April - when will the first day of  SMB loss be?

and

PRECIPITATION Snowfall very much below average in the last week until this day - when snow drought ended. But GFS says precipitation low for the next 5 days result - see image of cumulative precipitation 21-26 March..... result being...

SMB remains well below average by maybe 75 GT , circa 20%.

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

Dry days also mean sunny days - surface melt tends to reduce albedo of snow, though not enough melt yet for run-off?
________________________________________________________________________
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.
_______________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on March 28, 2020, 12:55:59 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 27 March 2020


Accumulated Data 1 Sept 2019 to 27 March 2020

Melt Not long until April - when will the first day of  SMB loss be?
On Sunday 29th a brief spell of above freezing temps on the SW coast - but cloud and rain/snow mix, so not enough warmth for a net SMB loss?

and

PRECIPITATION Snowfall mostly below average in the last week.
GFS says precipitation snow/rain on the 28th and 29th, then a snow drought for the foreseeable future.

SMB remains well below average by maybe 75 GT , circa 20%.

SMB much above average in the coastal SE, NE, & NW.
Elsewhere mostly average to 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.
_______________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Tor Bejnar on March 28, 2020, 02:19:33 PM
I don't think of the Humboldt Glacier and doing much (off of Kane Basin in the NW part of Greenland - basically where the large light pink area is), but the light pink is suggestive more ice is moving that what meets the eye (or at least 'my eye').
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 03, 2020, 10:37:54 PM
I missed the first melt event of this year on March 30 & 31 (and an almost invisible spot on April 1.

Here is March 31...
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 11, 2020, 03:27:01 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 10 April 2020


Accumulated Data 1 Sept 2019 to 10 April 2020

Melt 3 weeks after Solstice - when will the first day of  SMB loss be?
On Sat 11th & Sunday 12th a spell of above freezing temps on the SW coast - enough warmth for a net SMB loss? Certainly should show up on the melt graphics.

and

PRECIPITATION A big dump a wekk ago and then snowfall mostly below average in the last week.

SMB remains well below average by maybe 75 GT..

SMB much above average in the coastal SE, NE, & NW.
Elsewhere mostly average to 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]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Tor Bejnar on April 11, 2020, 03:45:56 PM
IIRC from a discussion last year, the greyed areas on the Greenland melt charts (SMB daily and SMB annual accumulated) show a range from '2nd highest' to '2nd lowest' values.  Where the red 2011-12 line goes off by itself, it shows the record year off by itself.  On the daily record, the 2019 blue line is off by itself for a day at the end of September.  (See the spot of 'white' above the blue "V" on the attached enlargement.  There is also a record daily high earlier in the month, also shown.)  Other peaks and dips might also be records, but the lines are too thick to show any 'white'.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on April 12, 2020, 12:03:47 AM
Gerontocrat, thank you for these reliable updates. I noticed the last one did not include the 2018-19 line, if you could put it back it would be much appreciated. I am kinda hoping this year will pick up some extra snow soon, like last year did around this time.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 12, 2020, 02:28:50 PM
Gerontocrat, thank you for these reliable updates. I noticed the last one did not include the 2018-19 line, if you could put it back it would be much appreciated. I am kinda hoping this year will pick up some extra snow soon, like last year did around this time.
DMI took last year off the graph. They did the same last year.

No point in contacting them - they do not answer emails, e.g. I have asked for any chance of getting daily SMB data as a txt, csv, xls file. They have it, they obviously aren't inclined to give it.

So I have no numeric data from this site. Maybe I should try NSIDC ?

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 14, 2020, 02:17:43 PM
I missed the first day of SMB loss in calendar year 2020.

It was on April 11th - due to almost zero precipitation and, according to DMI, sublimation, i.e. not surface melt. Meanwhile NSIDC say there was surface melt on that day.

Sublimation makes sense as it is snow turning into vapour, which reduces snow mass (SMB). Surface melt, if in small quantities, is likely to just soak into the snow surface without run-off, i.e. no loss of mass.
__________________________
ps: On the 12th DMI shows surface melt - at the snowline edge near the SW coast..
But it also snowed, and likely rained at lower levels.

So no SMB loss, but the surface melt on this day likely to have been caused by rain at the lowest levels, not sunshine.

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 15, 2020, 03:22:51 PM
GRACE-FO data on the GIS mass change to Feb 2020 released
- ftp://isdcftp.gfz-potsdam.de/grace-fo/GravIS/GFZ/Level-3/ICE/GIS/

Annual GIS mass loss 431 GT (= 1.2 mm sea level rise), of which 256 GT was in the West (see map attached)
Total mass loss since 2002 3,800 GT (= 10.5 mm sea level rise).

i.e. last 12 month rate of SLR double the average of 2002-2020.

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 on April 16, 2020, 03:16:07 AM
The GRACE graph seems to be nearly linear for 3 years (2017 to 2019?), without the annual increase and decrease seen in all the other years.  Doesn't seem like real data, even though it meanders a bit towards the end.  Is there an explanation?

 
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: wdmn on April 16, 2020, 04:27:00 AM
The GRACE graph seems to be nearly linear for 3 years (2017 to 2019?), without the annual increase and decrease seen in all the other years.  Doesn't seem like real data, even though it meanders a bit towards the end.  Is there an explanation?

The GRACE mission ended 2017, and GRACE-FO was not launched until May 2018, so there was a period without any data collection.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 16, 2020, 02:00:18 PM
The GRACE graph seems to be nearly linear for 3 years (2017 to 2019?), without the annual increase and decrease seen in all the other years.  Doesn't seem like real data, even though it meanders a bit towards the end.  Is there an explanation?
GRACE started to die in mid 2017, many years beyond its expected life.
The regular monthly updates from GRACE-FO started from October 2018. Hence the odd bit on the graph for that period. Since my and LibreOffice's graphing skills are limited - that's all, folks.

This is the data for that interregnum (posh word, what?)
 
YEAR    Measure   DATE   Cumulative Mass Loss
2017.360   -1,631   May-2017   -3045.819
2017.440   -1,640   Jun-2017   -3054.616
2018.455   -1,825   Jun-2018   -3239.049
2018.520   -1,824   Jul-2018   -3238.588
2018.831   -1,915   Oct-2018   -3329.073
2018.873   -1,916   Nov-2018   -3330.541
2018.957   -1,897   Dec-2018   -3311.348
_______________________________________________
interregnum
noun
- a period when normal government is suspended, especially between successive reigns or regimes.
- the period in English history from the execution of Charles I in 1649 to the Restoration of Charles II in 1660.
- an interval or pause between two periods of office or other things.
"the interregnum between the discovery of radioactivity and its detailed understanding"
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 21, 2020, 03:33:17 PM
Melt from Rain

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

I for one, always associate melt in Greenland with Sunny Days, i.e. from insolation (+ a warmer atmosphere).

But last year I came across a paper entitled...
"Increased Greenland melt triggered by large-scale, year-round cyclonic moisture intrusions", i.e. rain. ( https://www.the-cryosphere.net/13/815/2019/ )

And here is an example - on the attached  the blue patch is intense precipitation on the 20th April. One assumes - SNOW!
But at the snowline edge, there was melt on that day, the little bits of red on the melt graph. It must be due to precipitation at the edge as rain, not snow.

So as the years go by, it could be rain, not sunny days, that causes a catastrophic increase in Greenland melt.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: kassy on April 21, 2020, 03:49:13 PM
Or they could take turns.  ;)

Cool find. Do you expect more of this in the coming month?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 21, 2020, 04:52:01 PM
Or they could take turns.  ;)

Cool find. Do you expect more of this in the coming month?
Yes - depending on the weather bringing warmth & moisture.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 21, 2020, 05:56:58 PM
SMB & melt Data

Ruth Mottram & The DMI have come up with a hhh...uuuuuu,,,,gggge basket of goodies.
& it is not my birthday.
Boredom of self-isolation at bay for a few days?
SMB data + Grace-FO data cshould be interesting

ps: When I wrote to them some time ago I gave the ASIF quite a big plug.
________________________________________

Quote
Ruth Mottram <rum@dmi.dk>
20 Apr 2020, 10:30 (1 day ago)
to me, info@polarportal.dk, Martin

Dear xxxxxx   
Quote
(Gerontocrat is being coy as to his identity today)
thanks very much for your message, and many apologies for the late response - I recently found the reply I thought I'd sent to you in my drafts folder, apparently it did not send.

However, the reason I was looking for your mail address was to let you know some good news. We have decided to make our datasets much more easily available and they are now once again up on our server. .
You can grab the daily updated numbers here:


http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/GSMB_2020.txt


and the previous years are available here:

http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


I'd liek to emphasise that these are model products and as we hopefully make clear in the disclaimer, they are provided only for information and may change. A different model may get slightly different results!

If you need more information or help in understanding the numbers, please don't hesitate to get in touch


Best wishes


Ruth Mottram
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: blumenkraft on April 21, 2020, 07:00:14 PM
Thanks so much, Ruth. And you too, Gero!
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 22, 2020, 10:56:05 PM
Another (bigger) dose of melt from rain.
Yet another fight between warmth & cold.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 23, 2020, 05:42:01 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 22 April 2020


Accumulated Data 1 Sept 2019 to 22 April 2020


Sublimation (on the West coast), MELT and precipitation (both on the East coast) all on the same day.

PRECIPITATION greater than melt so SMB daily increase mostly above average in recent days.

Accumulated SMB still somewhat below average.

WARMTH persisting until at least Sunday 26th April should produce more melt.
________________________________________________________________________
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 balan 2ce (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.
_______________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on April 23, 2020, 05:50:31 AM
Just like last year, the 2nd half of April is delivering some of the missing snow. Hopefully this will continue.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 25, 2020, 03:55:41 PM
http://polarportal.dk/en/greenland/surface-conditions/

The coast of the southern half of Greenland (i.e. at low altitude) is above freezing.

The 23rd saw much precipitation and much melt b= above average increase in SMB
the 23th saw almost no precipitation and much melt = almost zero increase in SMB.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Sublime_Rime on April 25, 2020, 07:51:44 PM
Melting events over past couple days seems to have reduced albedo (bluish tint) over the lower-altitude areas on the east and west coasts of central Greenland. Senior posters: Does this seem significantly early for this to occur? Likely to precondition continued melt in these areas?

Looks like forcast calls for another 3-4 days at least of significantly high temp anomalies for greenland as a whole, before returning to normal later in the week.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 26, 2020, 02:17:14 PM
http://polarportal.dk/en/greenland/surface-conditions/

A spike in melting April is earlier than average, but in these years it would feel strange not to have an event in April.

Meanwhile, the weather had a busy day yesterday (25 April), sublimation, melt and precipitation. Result - average SMB daily gain.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 27, 2020, 08:26:34 AM
First bash at SMB data released by DMI attached.
See http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Hope to be looking at the SMB data against GRACE-FO data later this week.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on April 27, 2020, 02:09:59 PM
Nice! Now they just need to add back the 1981-2010 mean.
And now I can see the late April upswing this year is smaller than last year.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 27, 2020, 04:46:19 PM
Nice! Now they just need to add back the 1981-2010 mean.
And now I can see the late April upswing this year is smaller than last year.
and to give the data split into the drainage basins.
But which drainage basin definition and map are they using?
There is the map used for GRACE-FO data, and there is the map used by e.g.
Eric Rignot et al in the PNAS paper "Forty-six years of Greenland Ice Sheet mass balance
from 1972 to 2018"  See attached

also attached is 1st bash at the melt data - which is in % area. The cumulative figure is a totally  unscientific rough guide to the intensity of the melting season. Simply put, if daily melt % is 25% for 4 days in a row, that gives a cumulative melt day of 1.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Stephan on April 27, 2020, 10:03:19 PM
very nice, gerontocrat.
Looks like there is a lot of spreadsheet work ahead of you. Good luck with that, and looking forward for further nice charts...
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 28, 2020, 08:21:41 PM
Sometimes it is good to look beyond the land to the surrounding seas.

To Greenland's West is Baffin Bay - with a sea ice area at lowest in the satellite record for the last 21 days, currently a country mile below 2nd placed 2005. The West coast is nearly sea ice free up to and beyond 70 North.

To the East is the Greenland Sea - and despite loads of ice export from the Fram, sea ice area on the southern coast (up to 70 North) is well below average, and north of that looking pretty ropy.

i.e. the Southern half of Greenland is totally (as near as makes no difference) exposed to weather coming in from an open water ocean. I do not know how this compares with an average year and the resulting impact of earlier open water ocean weather systems on snowfall, rain and melting (SMB) and glacial melt both on land and under marine terminating glaciers (total GIS mass balance). But I doubt it will do the Greenland Ice Sheet any favours.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on April 30, 2020, 10:59:37 PM
Linking DMI & GRACE-FO data

GRACE-FO gives us the changes  in the NET MASS BALANCE of Greenland.
DMI now gives us the change in surface Mass Balance (SMB)

So we now have a simple equation.

GROSS MASS Change = NET MASS loss (gain) + SMB gain (loss), and that mass change is (almost) always a mass loss.

The attached table and graph shows that the gross mass loss increases every month - even in winter. i.e. glacial melt, mostly from marine-terminating glaciers continues all winter by not a small amount.
__________________________________
ps: If DMI give data for years before 2018 (2017-18 were the years of no or sporadic GRACE data) then the table & graph can be extended backwards).
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 01, 2020, 03:13:18 PM
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Greenland SMB @ 30 April

In the last few days continuous melt on the coastal fringe of southern Greenland (especially the East coast) + a mixture of sublimation & precipitation & dry periods.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 09, 2020, 06:49:32 PM
http://polarportal.dk/en/greenland/surface-conditions/
https://climatereanalyzer.org/wx/fcst_outlook/

The somewhat substantial probable warming event in the Arctic for the next 5-10 days looks like having only a limited effect on Greenland.

Melting on the Southern coasts and maybe fairly dry except for in the usual place - the SE corner.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 12, 2020, 03:01:39 PM
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


So far melting remains modest, and SMB gain this season also well below average.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 on May 12, 2020, 04:22:00 PM
It will be interesting to see if the line this year remains below last years, and thus turns down in the next ~2 weeks.

Combine that with the predictions that this year has a 75% chance of being the warmest year on record, and it should make for an interesting summer in Greenland.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 14, 2020, 10:18:35 AM
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


So far melting remains modest,but persistent , and gradually increasing, while SMB gain this season also well below average.

With above average ocean open water, especially on the West coast, forecasts of a long hot year, the possibility of large mass losses from the GIS must be above average.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 16, 2020, 12:35:47 AM
On the melting season thread much talk about pre-conditioning.
Perhaps the same applies to the Greenland spring & summer.

The two images attached show how the southern half of Greenland is now totally exposed to open water ocean - and that ocean is already warming up. (Sea ice in Baffin Bay has been lowest in the satellite record for 38 days in a row.)

Weather arriving from the open water ocean is somewhat different from that which passes over an expanse of frozen water.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Frivolousz21 on May 16, 2020, 08:54:26 AM
On the melting season thread much talk about pre-conditioning.
Perhaps the same applies to the Greenland spring & summer.

The two images attached show how the southern half of Greenland is now totally exposed to open water ocean - and that ocean is already warming up. (Sea ice in Baffin Bay has been lowest in the satellite record for 38 days in a row.)

Weather arriving from the open water ocean is somewhat different from that which passes over an expanse of frozen water.

It's definitely seen huge preconditioning.



Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 16, 2020, 12:25:42 PM
http://polarportal.dk/en/greenland/surface-conditions/

Melt, though not large, is persistent, not quite enough to result in an SMB loss, but enough to keep daily surface mass gain very much below average.

Looking at the GFS forecast suggests many more days of the same - a slow burn.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 17, 2020, 11:19:22 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


SMB gain is zero on this day (16May).
But despite the considerable area of melt and little snowfall, surface mass did not reduce. I presume this is because the DMI model is assuming that much of the current melt is not leading to run-off, i.e. the water from melted surface snow is sinking into the top lowers of snow.

My guess is that this is a potential considerable uncertainty in the output from the model. I believe there is only one station with a long-term record of river discharge (Watson River discharging into Baffin Bay). Greenland needs more weather stations!

Accumulated SMB gain this year at 500GT is about 50GT below the average.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: paolo on May 17, 2020, 02:00:24 PM
But despite the considerable area of melt and little snowfall, surface mass did not reduce. I presume this is because the DMI model is assuming that much of the current melt is not leading to run-off, i.e. the water from melted surface snow is sinking into the top lowers of snow.

There is also the water that penetrates the glacier, but freezes or remains trapped inside the glacier without joining the sub-glacial water circulation system.
Which is actually very difficult to model
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 17, 2020, 04:55:36 PM
Meanwhile, GFS forecasts for the next 10 days

- West & Central Greenland will be dry as a bone. Even the modest precipitation in the East will be mostly confined to the coastal fringe. The usual exception is that small area in the SE Corner.

- AVERAGE (and the daily forecast) temperatures imply continual melting on the SW coastal quarter.

My guess is that some days will see a modest SMB loss - and if not, well below average SMB gain.

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 on May 17, 2020, 08:54:26 PM
Sounds like we are set up to nearly flat line on accumulation for the next 7 to 10 days, which will get us to the point in the year where, at least in recent years, we have tipped over to loss for the summer...
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 18, 2020, 12:43:18 PM
http://polarportal.dk/en/greenland/surface-conditions/ 17th May

A small SMB daily loss.

The SMB today image shows that it was a combination of low precipitation (blue), sublimation (pink), and the relatively small amount of run-off (red (& pink?)) that resulted from surface melt.

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 20, 2020, 09:09:18 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


Minuscule SMB losses in the last 4 days, the result of some melt + very low precipitation.
Accumulated SMB gain this year at 500GT is about 50GT below the average.

Modest precipitation and modest melt look set to continue to the end of the month.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 20, 2020, 10:13:20 AM
& attached is the graph that shows that if SMB gain has peaked, it has peaked about 2 weeks early & somewhere between 50 to 75 GT less than average.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 21, 2020, 09:13:26 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


Data as at 20th May 2020

Minuscule SMB losses in the last 5 days, the result of some melt + very low precipitation.
Accumulated SMB gain this year at 500GT is about 75GT below the average.

Modest precipitation and modest melt look set to continue to the end of the month.

If the SMB gain for this year has peaked at just almost 500GT, it is about 3 weeks early and nearly 100 GT below the average of nearly 600GT.
__________________________________
ps:- I have written to DMI & requested they download the average SMB & Melt daily data. I am hopeful for a +ve result next week
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 23, 2020, 08:30:26 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 22 May 2020


I didn't see this sort of melt coming at all. A large area of melt but an SMB gain. If you compare the daily SMB and melt maps you can see..
- In the West & North insolation causing both sublimation (inland)and run-off (coastal).
- in the SouthWest melt is associated with precipitation - but as  rain.

It is a reminder that at lower altitudes precipitation during the warmer months is likely to be a mixture of snow and rain.
__________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Stephan on May 23, 2020, 08:47:06 AM
- in the SouthWest melt is associated with precipitation - but as  rain.
Wet and not so warm times are expected in S Grønland. Forecast for Narsarsuaq for May 23 - June 05, 2020.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on May 28, 2020, 10:41:18 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 27 May 2020
SMB cumulative gain still dithering around the current max of 500 GT

The very large melt on 22nd May did not happen - DMI revised the data.

You can see from the maps where at lower altitudes precipitation during the warmer months is likely to be a mixture of snow and rain.

No significant acceleration in melt likely in the next 5 days - but after that GFS says maybe.
Ditto for precipitation.
__________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Stephan on May 28, 2020, 05:45:30 PM
Melting season makes a little pause as Freya Gletscher Webcam shows (May 26)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 02, 2020, 02:44:19 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 1 June 2020

SMB cumulative up by 5GT since the last posting.
SMB loss of 0.4GT on this day - low oprecip+average melt.

Looks like high afternoon temperatures will generate a significant melt in the next 3 days or so, but moderating after that.
__________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 03, 2020, 12:52:23 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 2 June 2020

High precipitation greater than above average melt = SMB gain

Note that in the south much precipitation falling as rain but mostly not resulting in run-off

Looks like even higher afternoon temperatures will generate a significant melt in the next 3 days or so, but moderating after that.

Also in the south - rain. If that persists increased run-off to be the result?
__________________________________
[/quote]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: paolo on June 03, 2020, 08:28:33 PM
Image Sentinel-2 of 02/06 (B8A/B03/B02) of SE Greenland.
The melt seems to be well established
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 04, 2020, 12:32:49 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 3 June 2020

Very high precipitation greater than much above average melt = SMB gain


Note that in the south west much precipitation falling as rain but mostly not resulting in run-off.

Looks like continuing high afternoon temperatures will generate a significant melt in the next 3 days or so.

Also in the south - more rain. If that persists increased run-off to be the result? Definitely will do some more damage to the ice sheet in any event.
__________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 05, 2020, 12:18:57 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 3 4 June 2020 - same as 3rd June

High precipitation greater than much above average melt = SMB gain (but much less than June 3)


Note that in the south west some precipitation falling as rain but mostly not resulting in run-off.

Looks like continuing high afternoon temperatures will continue the significant melt for the next 3 days or so.

Also in the south - a bit more rain/snow mix but getting dryer. If that high melt persists increased run-off to be the result? Definitely will do some more damage to the ice sheet in any event.
_________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 06, 2020, 01:18:08 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 3 5 June 2020 - same as 3rd & 4th June

High precipitation greater than much above average melt = SMB gain (but much less than June 3)


Note that in the south west some precipitation falling as rain but mostly not resulting in run-off.

In the south - a bit more rain/snow mix but getting dryer in the coming days.
But as Greenland gets dryer looks like temperatures a bit cooler, i.e. less melt.
_________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 07, 2020, 02:48:43 PM
I wonder if melt + precipitation as rain & snow on such a scale is unusual?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 09, 2020, 12:36:28 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 3 8 June 2020 - very much the same as 3rd to 7th June

i.e. High precipitation minus much above average melt still = SMB gain (but much less than June 3)


GFS 5 day forecast says afternoon temperatures still much above freezing, and quite a lot of precipitation. Will persistent melt force increasing run-off leading to net SMB loss?
_________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 10, 2020, 12:05:51 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 3 9 June 2020 - very much the same as 3rd to 8th June. Definitely a melting event & set to continue.

i.e. High precipitation minus much above average melt still = SMB gain (but only just)


GFS 5 day forecast says afternoon temperatures still much above freezing, and note the warmth that is developing in the Greenland Sea and the entire East coast of Greenland.

Precipitation, if anything looks like being even higher. But much must fall as rain at low and perhaps even higher altitudes.. Will this persistent melt, especially as rain, force increasing run-off leading to net SMB loss?

This is a very active weather picture. This is a warmer wetter Greenland (at the moment).
_________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 10, 2020, 07:36:04 PM
GRACE-FO - Greenland Ice Sheet (GIS) mass loss to mid-March 2020.

It looks like the scientists recalculated GIS mass loss going all the way back to 2002. Perhaps this was the cause of a 2 month delay in new data. Hopefully from now on we might get data a bit earlier.

In the period mid-Feb to mid-March SMB increased by 30 GT, while GIS mass reduced by 100GT.
That means in the dead of winter there was a gross mass loss of 130GT - i.e. below surface melting of marine-terminating glaciers does not stop.

The attached graph shows the cumulative GIS gross mass change, cumulative SMB change, and cumulative net GIS mass loss from October 2018. If we get previous year SMB data from DMI, I should be able to go back to previous years.

I also attach cumulative mass loss graphs from 2002 to date. (Note that many months GRACE  data between June 2017 and September 2018 were not collected as the GRACE satellites died before GRACE-FO was launched.)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 11, 2020, 11:56:46 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 10 June 2020 - very much the same as 3rd to 8th June. Definitely a melting event & set to continue.

On this day very high precipitation minus much above average melt, results in a  sgnifcant SMB gain


GFS 5 day forecast says afternoon temperatures still much above freezing, and warmth that is developing in the Greenland Sea and the entire East coast of Greenland.

Precipitation, looks like remaining high. But much must fall as rain at low and perhaps even higher altitudes.. Will this persistent melt, especially as rain, force increasing run-off leading to net SMB loss? NOT YET.

This is a very active weather picture. This is a warmer wetter Greenland (at the moment).
_________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 12, 2020, 12:39:57 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


Data as at 11 June 2020 - very much the same as 3rd to 10th June.

Definitely a real and very persistent melting event & set to continue.

On this day very high precipitation minus even more above average melt, results in a  significant SMB gain.

GFS 5 day forecast says afternoon temperatures still much above freezing, and yet more warmth  in the Greenland Sea and the entire East coast of Greenland.

Precipitation, looks like remaining high. But much must fall as rain at low and perhaps even higher altitudes.. Will this persistent melt, especially as rain, force increasing run-off leading to net SMB loss? NOT YET.

This is a very active weather picture. This is a warmer wetter Greenland at the moment, with no sign of any change - except perhaps getting even warmer).
_________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Stephan on June 12, 2020, 02:24:17 PM
mostly wet in the next days and then drier and warmer in the south. Forecast Narsarsuaq 12 through 25 June, 2020.

dry, mild and sunny and more melt ponds on Freya Gletscher in the (Northern) East of Grønland. It even looks as if the snow on the glacier is melting and bare ice is visible on its surface.

See attached pictures.

Edit: Just by chance I found that grixm has posted the same picture in the Greenland melt season thread.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 13, 2020, 08:57:06 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 12 June 2020 - very much the same as 3rd to 10th June.

Definitely a real and very persistent melting event, that looks like moderating a bit and then after 5 days set to increase again..

On this day  high precipitation minus even more well above average melt, results in a  significant SMB gain of just over 3GT.

Definitely a real and very persistent melting event, that looks like moderating a bit and then after 5 days 0r so may increase again..

Precipitation looks like remaining high for the duration.
_________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 14, 2020, 06:22:41 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 13 June 2020 - very much the same as 3rd to 12th June.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 15, 2020, 02:29:53 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


Data as at 14 June 2020 - very much the same as 3rd to 13th June.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on June 15, 2020, 06:32:15 PM
The SMB positive event is becoming quite prolonged, making up a bit of the ground lost during the lackluster accumulation season.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 16, 2020, 10:03:04 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 15 June 2020 - very much the same as 3rd to 13th June.

Despite these significant daily SMB gains at a time of high melting, the cumulative SMB gain for the year is still well below the long-term average.

Starting at the weekend melt may increase and precipitation decrease.

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 17, 2020, 12:51:42 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 16 June 2020 - very much the same as 3rd to 115th June.

Despite these significant daily SMB gains at a time of high melting, the cumulative SMB gain for the year is still well below the long-term average.

Starting at the weekend melt may increase and precipitation decrease. And Monday could be the first day this year for a major SMB net loss.(Very warm & very little precipitation.)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 18, 2020, 01:22:34 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


Data as at 17 June 2020 - very much the same as 3rd to 16th June.
But a bit dryer, so melt > precipitation = SMB loss.


Despite these significant daily SMB gains at a time of high melting, the cumulative SMB gain for the year is still well below the long-term average.

Starting at the weekend melt is very likely to increase and precipitation decrease. And SUNDAY could be the first day this year for a major SMB net loss.(Very warm & little precipitation, much as rain in the SE corner.)
[/quote]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 19, 2020, 12:56:32 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 18 June 2020 - very much the same as 3rd to 1th June.
But a bit wetter, so melt< precipitation = (a small) SMB loss.


Despite the recent significant daily SMB gains at a time of high melting, the cumulative SMB gain for the year is still well below the long-term average.

Starting at the weekend melt is very likely to increase and precipitation decrease. And SUNDAY could be the first day this year for a major SMB net loss.(Very warm & little precipitation, much as rain in the SE corner - as usual.)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 20, 2020, 12:32:42 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 19 June 2020 - very much the same as 3rd to 18th June.
But a bit dryer, so melt > precipitation = (a small) SMB loss.


Despite the recent significant daily SMB gains at a time of high melting, the cumulative SMB gain for the year is still well below the long-term average.

Starting at the weekend (i.e. today) melt is very likely to increase and precipitation decrease. And SUNDAY could be the first day this year for a decent SMB net loss. (Very warm & little precipitation, much as rain in the SE corner - as usual.)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 21, 2020, 12:10:12 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/


Data as at 20 June 2020 - very much the same as 3rd to 19th June.
But somewhat dryer, so even though melt is less than yesterday, it is still > precipitation = (a modest) SMB loss.


SUNDAY (today) could be the first day this year for a decent SMB net loss. (Very warm & little precipitation, much as rain in the SE corner - as usual.)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 22, 2020, 12:26:06 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/

Data as at 21 June 2020 - very much the same as 3rd to 20th June.
But sufficient precipitation , so that even though melt was highest so far (just) this year, the result was a merely a modest SMB loss.

Yesterday I wrote...
SUNDAY (today) could be the first day this year for a decent SMB net loss.

I was wrong. Ho hum.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 23, 2020, 12:31:03 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 22 June 2020 - very much the same as 3rd to 21st June,
except that melt rose to 29% of the surface area of Greenland,  while precipitation was a bet less than in recent days. The result was a merely an SMB loss of just above 3GT, well above average..

Sunday was supposed to be the first day this year for a decent SMB net loss.
Sunday became Monday


_________________________________________________
You have to click on each image to see it in its full glory - (forum software change - humph.)
___________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 24, 2020, 10:44:05 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 23 June 2020 - very much the same as 3rd to 22nd June,
except that melt rose to 32% of the surface area of Greenland,  while precipitation was also a bit more than in recent days. The result was an SMB loss of just above 1.3 GT, which is below average..

Precipitation and temperatures see to indicate more of the same for the next few days, with most precipitation on the  eastern half of Greenland, i.e. most SMB loss in the Western coastal region.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Freegrass on June 24, 2020, 11:18:38 PM
Shit just went bad on Greenland...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fnsidc.org%2Fgreenland-today%2Fimages%2Fgreenland_daily_melt_plot_tmb.png&hash=edf0882c366d5e22471b0d8a1ddbcd27)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 25, 2020, 12:37:51 AM
Shit just went bad on Greenland...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fnsidc.org%2Fgreenland-today%2Fimages%2Fgreenland_daily_melt_plot_tmb.png&hash=edf0882c366d5e22471b0d8a1ddbcd27)
The percentage area of melt is pretty much the same on the NSIDC Greenland Today graph and the DMI graph. High, but not that unusual

This year is nothing special SO FAR.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 25, 2020, 12:12:44 PM
Shit just went bad on Greenland...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fnsidc.org%2Fgreenland-today%2Fimages%2Fgreenland_daily_melt_plot_tmb.png&hash=edf0882c366d5e22471b0d8a1ddbcd27)
The percentage area of melt is pretty much the same on the NSIDC Greenland Today graph and the DMI graph. High, but not that unusual

This year is nothing special SO FAR.
Perhaps I will have to eat my words.....

Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 24 June 2020 - very much the same as 3rd to 23rd June,

except that melt rose again, now at 34.5% of the surface area of Greenland,  while precipitation stayed pretty strong. The result was an SMB loss of just above 2 GT, which is close to average..

Precipitation and temperatures seem to indicate more of the same for the next few days, with most precipitation on the  eastern half of Greenland, i.e. most SMB loss in the Western coastal region and also the far north.

But each day the melt gets stronger, and the temperature anomalies remain strongly +ve, especially in the north on both sides of the Nares strait. How the arch in the strait has survived given the strong meltwater runoff and warmth I do not know. Perhaps it will just dissolve in situ?

- it is this persistence in combined high melt and precipitation that is interesting -  has a pattern of higher-energy weather set in? (AGW + Polar amplification?)
_______________________________________-
ps For those with failing eyesight - e.g. me, click on the images for a clearer view.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 26, 2020, 09:34:47 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 25 June 2020 - very much the same as 3rd to 24th June,

except that melt rose yet again, now at 35.8% of the surface area of Greenland,  while precipitation stayed not as strong. The result was an SMB loss of nearly 3 GT, which is close to and a bit above average..

Precipitation and temperatures seem to indicate more of the same for the next few days, with most precipitation on the  eastern half of Greenland, i.e. most SMB loss in the Western coastal region and also the far north.

But each day the melt gets stronger, and the temperature anomalies remain strongly +ve, especially in the north on both sides of the Nares strait. How the arch in the strait has survived given the strong meltwater runoff and warmth I do not know. Perhaps it will just dissolve in situ?

- it is this persistence in combined high melt and precipitation that is interesting -  has a pattern of higher-energy weather set in? (AGW + Polar amplification?)
_______________________________________-
ps For those with less than perfect eyesight - e.g. me, click on the images for a clearer view.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 on June 26, 2020, 08:40:13 PM
Very early in the year, and we are about 100 GT below the average.  Is this the year we end up with a negative for SMB?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 27, 2020, 11:00:44 AM
Very early in the year, and we are about 100 GT below the average.  Is this the year we end up with a negative for SMB?
Below the average, yes, but above last year. I think it can only happen if precipitation in the next two months is well below average - i.e. sunny days & dry. See below....
________________________________________________
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 26 June 2020. Melt very much the same as 3rd to 25th June, i.e. gradual intensification of melt. Melt rose yet again, now at 36.4% of the surface area of Greenland. 
Precipitation for once was low. The result was an SMB loss of nearly 3.6 GT, which is above average..

Temperatures seem, if anything, rising for the next few days, with real heat in the long afternoons. Most precipitation forecast to be confined to the SE quadrant of Greenland, and somewhat lower than in recent weeks.

 i.e. There may be some SMB gains in that SE quadrant and perhaps significant losses in all the rest of the coastal regions.

Will Greenland get dryer for the rest of the melt season?
_______________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on June 27, 2020, 01:30:57 PM
With the average SMB gain at nearly 400GT, it would take a very exceptional year to reach negative territory. So far this year is not showing the signs, but surprises can happen.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 28, 2020, 07:35:08 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 27 June 2020. Melt very much the same as 3rd to 26th June, i.e. gradual intensification of melt. Melt rose yet again, now at 37.2% of the surface area of Greenland. 
Precipitation for a second time was low. The result was an SMB loss of just over 4 GT, which is above average..

Temperatures seem, if anything, rising for the next few days, with real heat in the long afternoons. Most precipitation is forecast to be confined to the SE quadrant of Greenland, and continuing somewhat lower than in recent weeks.

 i.e. There may be some SMB gains in that SE quadrant and perhaps even greater significant losses in all the rest of the coastal regions.

Will Greenland get dryer for the rest of the melt season? They tell us that dry sunny days are the no. #1 snow & ice killer on the land surface during the brief summer to mid-August.
_______________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 29, 2020, 12:18:31 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 28 June 2020. Melt very much the same as 3rd to 27th June, i.e. gradual intensification of melt. Melt rose yet again, now at 37.5% of the surface area of Greenland. 
Precipitation a bit higher. The result was an SMB loss of just over 2 GT, which is below average..
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on June 30, 2020, 08:07:40 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 29 June 2020. Melt very much the same as 3rd to 28th June, i.e. though perhaps melt has peaked.. Melt down a teensy bit to 37.1% of the surface area of Greenland. 
Precipitation a bit higher. The result was an SMB loss of just over 2 GT, which is below average..

The melt and meltwater run-off in the NE and North is really quite spectacular. A lot of H2O in liquid form must be getting into the Nares Strait from both sides.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 01, 2020, 10:58:48 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 30 June 2020. Melt very much the same as 3rd to 28th June. I thought perhaps melt has peaked, but melt up a teensy bit to 38.2% of the surface area of Greenland. 
Precipitation a bit lower. The result was an SMB loss of just over 3 GT, which is a bit above average..

The melt and meltwater run-off in the NE and North is really quite spectacular. A lot of H2O in liquid form must be getting into the Nares Strait from both sides. You can see that even more clearly in the accumulated SMB anomaly graph.

It still looks as if melt might peak within the next 3 days. But GFS also forecasts precipitation will be much less (ha ha?). The chances of a record low SMB gain for the year look very remote indeed, though a below average gain might be considered the new normal for a few years more.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 02, 2020, 05:27:00 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 1 July 2020. Melt very much the same as 3rd to 30th June. I thought perhaps melt has peaked, but melt is gain up a teensy bit to 38.5% of the surface area of Greenland.
Precipitation much lower. The result was an SMB loss of 5.6 GT, which is very much above average, and the first b> 5gt daily SMB for this melt season.

This illustrates well how dryness is the key to SMB loss even when melt is high.
I also don't remember melt being so consistently high for so long.


It still looks as if melt might peak within the next 3 days. But GFS also forecasts precipitation will be remain low. The chances of a record low SMB gain for the year look very remote indeed, though a below average gain might be considered the new normal.

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 03, 2020, 02:05:48 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 2 July 2020. Melt very much the same as 3rd June to 1 July. Melt is down a bit to 37.2% of the surface area of Greenland.
Precipitation about the same - low. The result was an SMB loss of 4.4 GT, which is around average.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 04, 2020, 11:20:33 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 3 July 2020. Melt very much the same as 3rd June to 1 July. Melt is down a bit to 36.8% of the surface area of Greenland.
Precipitation very low. The result was a daily SMB loss of exactly 5GT, which is a bit above average.

You can see from the SMB graph that cumulative SMB gain for the year (493 GT) is already less than the final result for 2017-18 (a bit above 500 GT).

However, matching last year (2018-19) would require a further SMB loss of around 320GT, which is highly unlikely. It would need continuous high daily melt and a continuous drought over Greenland for the next 8 weeks.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 05, 2020, 11:40:22 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 3 July 2020. Melt very much the same as 3rd June to 1 July. Melt is down a bit to 36.8% of the surface area of Greenland.
Precipitation very low. The result was a daily SMB loss of exactly 5GT, which is a bit above average.

You can see from the SMB graph that cumulative SMB gain for the year (493 GT) is already less than the final result for 2017-18 (a bit above 500 GT).

However, matching last year (2018-19) would require a further SMB loss of around 320GT, which is highly unlikely. It would need continuous high daily melt and a continuous drought over Greenland for the next 8 weeks.

[/quote]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 06, 2020, 01:19:02 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 5 July 2020. Melt very much the same as 3rd June to 4 July. Melt is down a bit to 36.5% of the surface area of Greenland.
Precipitation low. The result was a daily SMB loss of 4.75 GT, which is a bit above average.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 07, 2020, 02:22:22 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 6 July 2020.
Melt very much the same as 3rd June to 5 July. Melt is down a bit to 35.1% of the surface area of Greenland.
Precipitation very low. The result was a daily SMB loss of 5.4 GT, which is above average for this day.

Might be a extra high melt on Thursday + low precipitation apart frm the SW corner - but that looks like mainly rain. So maybe a big daily SMB loss. After that looks more like melt moderating somewhat.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 08, 2020, 02:33:13 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 6 July 2020.
Melt very much the same as 3rd June to 6 July. Melt is up a bit to 35.1% of the surface area of Greenland.
Precipitation   low. The result was a daily SMB loss of 5.7 GT, which is above average for this day and the highest so far this year.

Might be an extra high melt on Thursday + low precipitation apart from the SW quadrant - but that looks like mainly rain. So maybe a big daily SMB loss. After that looks more like melt moderating somewhat.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Gray-Wolf on July 08, 2020, 03:23:44 PM
I feel a big Thanks is due to you for your tireless efforts across the whole site Gerontocrat!

Without your data getting my 'daily overview' of the world would be a much longer exercise but be it Arctic,Antarctic,Greenland,Global you're there in spades!!!
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 09, 2020, 07:01:59 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 8 July 2020.
Melt very much the same as 3rd June to 7 July. Melt is down a bit to 34.9% of the surface area of Greenland.
Precipitation   low. The result was a daily SMB loss of 5.8 GT, which is above average for this day and the highest so far this year.

Might be an extra high melt on Thursday (i.e. today) + low precipitation apart from the SW quadrant - but that looks like mainly rain. So maybe a big daily SMB loss. After that looks more like melt moderating considerably.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 10, 2020, 01:24:25 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 9 July 2020.
Melt very much the same as 3rd June to 8 July. Melt as expected rose to 37.8% of the surface area of Greenland.
Precipitation   higher than I expected. The result was a daily SMB loss of 3.6 GT, whichbelow average for this day.

It looks like melt moderating considerably during the next eek or two.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 11, 2020, 11:58:54 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 10 July 2020.
Melt very much the same as 3rd June to 9 July. Melt unexpectedly rose to 42.3% of the surface area of Greenland, highest for the year.
But Precipitation much higher than I expected. The result was a daily SMB loss of 2 GT, well below the average for this day.

It still looks like melt moderating considerably during the next week or two, but what do I know (sigh).
[/quote]
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 12, 2020, 06:27:21 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 11 July 2020.
Melt very much the same as 3rd June to 10 July. Melt down a bit to 39.7% of the surface area of Greenland, 2nd highest for the year.
But Precipitation highbut less than yesterday. The result was a daily SMB loss of 4.4 GT, about the average for this day.

It still looks like melt moderating considerably during the next week or two, but what do I know? (sigh).
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 13, 2020, 12:40:58 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 12 July 2020.
Melt very much the same as 3rd June to 11 July. Melt down a bit to 38.7% of the surface area of Greenland, 2nd highest for the year.
But Precipitation high.
The result was a daily SMB loss of 3.5 GT, below the average for this day.

ISo far this season is characterised by very much above average melt but above average precipitation resulting in a fairly average net SMB change so far - but 50 days to go.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 14, 2020, 12:04:27 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 13 July 2020.
Melt very much the same as 3rd June to 12 July. Melt the same at 38.7% of the surface area of Greenland, 2nd highest for the year.
But Precipitation high(ish).
The result was a daily SMB loss of 4.2 GT, about the average for this day.

ISo far this season is characterised by very much above average melt but above average precipitation resulting in a fairly average net SMB change so far - but 49 days to go.

SMB gain for this year to date is at 450 GT, about 70GT above the average for the year-end (31 August) of 380GT.
.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 14, 2020, 01:16:25 PM
Greenland SMB Change, Gross Mass Change and Net Mass Chnage to mid-may 2015

The GRACE-FO satellites are recording the net mass change of Greenland consisting of the melting of ocean-terminating glaciers less the increase in the Surface Mass Balance.

As we now have both sets of data, I can plot the gross and net mass change in the Greenland Ice Sheet. I can only go back to November 2018 for annual totals due to that the continuous monthly GRACE-FO data only begins in November 2018.

The table and graph show that submarine melting of glaciers by contact with the ocean continues throughout the winter months even when there is surface sea ice. Net mass loss is at over 500 GT per annum, while gross mass loss, i.e. melting of marine-terminating glaciers, is approaching 700GT per annum.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 14, 2020, 02:53:47 PM
Attached are the graphs of Greenland Ice Sheet Mass Loss from 2002 to Mid-May 2020.

Source is from GRACE-FO data processed by http://gravis.gfz-potsdam.de/greenland
Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences.
The data shows total ice mass loss at 3,893 GT and is monthly totals analysed by basin.

Meanwhile, the JPL  GRACE-FO data is available @
 https://podaac-tools.jpl.nasa.gov/drive/files/allData/tellus/L4/ice_mass/RL06/v02/mascon_CRI
This data shows total ice mass loss at 4,725 GT and is just a simple text file of monthly totals. A difference of 832GT is not good.

I suppose I will have to ask them about it.

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 15, 2020, 06:21:29 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 14 July 2020.
Melt very much the same as 3rd June to 13 July.

If you look at the SMB graph you would think that melt has been pretty average this year. But no, it has been very much above average continuously since the beginning of June. It is precipitation that has held back SMB losses.

Perhaps the future has arrived - a warmer wetter Greenland.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 16, 2020, 06:21:59 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 15 July 2020.
Melt very much the same as 3rd June to 14 July. Melt lower at 34.8% of the surface area of Greenland, still very much above average.
But Precipitation, for a change, low.
The result was a daily SMB loss of 5.6 GT, well above the average for this day.

Precipitation may be low for much of the next 5 to 10 days.
Melt looks about the same until the weekend, then increasing day by day by Tuesday and staying high for a few days more.

So we just might see some high SMB loss days during the next week.

SMB gain for this year to date is at 440 GT, about 60GT above the average for the year-end (31 August) of 380GT.
.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 17, 2020, 02:01:41 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 16 July 2020.
Melt very much the same as 3rd June to 15 July. Melt a ta higher at 35.1% of the surface area of Greenland, still very much above average.
But Precipitation low.
The result was a daily SMB loss of 6.2 GT, well above the average for this day and a record for this year.

Precipitation may be low for much of the next 5 to 10 days.
Melt looks about the same until the weekend, then increasing day by day by Tuesday and staying high for a few days more.

So we just might see some high SMB loss days during the next week.

SMB gain for this year to date is at 434 GT, about 55GT above the average for the year-end (31 August) of 380GT. Looks like SMB gain for the year will be below average - but by how much?

And how strong will be glacier calving and submarine melting of marine terminating glaciers
.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Sublime_Rime on July 18, 2020, 06:40:40 PM
Amazing Gerontocrat, thanks for your informative posts. I am noting in particular the marked depth of melt in the Northern and western low-altitude regions, while surface melt area only seems moderately above average. I am curious what the impact of this marked thinning will have on calving and the rate of ice flow from higher elevatons. Does anyone know of studies correlating the effect of surface melt to changes in ice flow rate?  I wonder if there could be a troublesome feedback loop set up here.

My apologies if this is inappropriate for a data thread, but I thought more people might be stopping by with more expertise than this humble biologist.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 on July 18, 2020, 07:46:33 PM
I suspect we will get to 10 GT loss in the next few days, and staying near that number for several days.   Will pretty quickly wipe out the 55 GT referenced above.

I believe there have been some studies linking high surface melt with increased flow rates, due to the water traveling to the base of the ice and lubricating the movement.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 18, 2020, 10:38:16 PM
Does anyone know of studies correlating the effect of surface melt to changes in ice flow rate?  I wonder if there could be a troublesome feedback loop set up here.
Try this one (open access)

https://www.nature.com/articles/s41467-018-05002-0
Hydrology and the future of the Greenland Ice Sheet
Gwenn E. Flowers
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 18, 2020, 10:47:03 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 17 July 2020.
Melt very much the same as 3rd June to 16 July. Melt lower at 33% of the surface area of Greenland, still very much above average.
But Precipitation very low.
The result was a daily SMB loss of 6.6 GT, well above the average for this day and a record for this year.

Precipitation may be low for much of the next 5 days.
Melt looks about the same until Sunday, then increasing  Monday Tuesday Wednesday and moderating a little bit after that.

So we just might see some high SMB loss days during the next week.

SMB gain for this year to date is at 427 GT, a bit below 50 GT above the average for the year-end (31 August) of 380GT. Looks like SMB gain for the year will be below average - but by how much?

And how strong will be glacier calving and submarine melting of marine terminating glaciers
.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on July 19, 2020, 12:27:36 AM
I think 2012 (exceptional GIS melt year) saw an acceleration of Greenland glaciers.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 19, 2020, 11:52:28 AM
I think 2012 (exceptional GIS melt year) saw an acceleration of Greenland glaciers.
A paper that does have more about it.
A switch from mass loss mainly down to glaciers calving  and acceleration to surface mass loss in SW Greenland. Latest GRACE-FO data (last image from GFZ data) confirms that most of that fresh water melt is heading into Baffin Bay.

Thanks Oren - well worth a search.

And it's an open access paper with loads of graphics & even a powerpoint you can download.

https://www.pnas.org/content/116/6/1934
Accelerating changes in ice mass within Greenland, and the ice sheet’s sensitivity to atmospheric forcing
Quote
Significance
The recent deglaciation of Greenland is a response to both oceanic and atmospheric forcings. From 2000 to 2010, ice loss was concentrated in the southeast and northwest margins of the ice sheet, in large part due to the increasing discharge of marine-terminating outlet glaciers, emphasizing the importance of oceanic forcing.

However, the largest sustained (∼10 years) acceleration detected by Gravity Recovery and Climate Experiment (GRACE) occurred in southwest Greenland, an area largely devoid of such glaciers. The sustained acceleration and the subsequent, abrupt, and even stronger deceleration were mostly driven by changes in air temperature and solar radiation. Continued atmospheric warming will lead to southwest Greenland becoming a major contributor to sea level rise.

Abstract
From early 2003 to mid-2013, the total mass of ice in Greenland declined at a progressively increasing rate. In mid-2013, an abrupt reversal occurred, and very little net ice loss occurred in the next 12–18 months. Gravity Recovery and Climate Experiment (GRACE) and global positioning system (GPS) observations reveal that the spatial patterns of the sustained acceleration and the abrupt deceleration in mass loss are similar. The strongest accelerations tracked the phase of the North Atlantic Oscillation (NAO). The negative phase of the NAO enhances summertime warming and insolation while reducing snowfall, especially in west Greenland, driving surface mass balance (SMB) more negative, as illustrated using the regional climate model MAR. The spatial pattern of accelerating mass changes reflects the geography of NAO-driven shifts in atmospheric forcing and the ice sheet’s sensitivity to that forcing. We infer that southwest Greenland will become a major future contributor to sea level rise.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 19, 2020, 12:10:49 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 18 July 2020.
Melt very much the same as 3rd June to 17 July. Melt lower at 35% of the surface area of Greenland, still very much above average.
But Precipitation very low.
The result was a daily SMB loss of 5.7 GT, well above the average for this day.

Precipitation may be low for much of the next 5 days.
Melt looks possibly to be up a bit today (Sunday), then increasing  Monday Tuesday Wednesday and moderating a little bit after that.

So we just might see some more high SMB loss days during the next week.

SMB gain for this year to date is at 421 GT, a bit more than 40 GT above the average for the year-end (31 August) of 380 GT. Looks like SMB gain for the year will end up below average - but by how much?

And how strong will be glacier calving and submarine melting of marine terminating glaciers
See previous posts on apparent changes to the relative importance of surface melt run-off and glacial calving and ocean melt of marine terminating glaciers.
.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on July 19, 2020, 12:16:03 PM
IMHO zero chance of not going below the average of 380GT. Best bet is hitting 200-300GT, but the field is wide open.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 20, 2020, 01:31:08 PM
EDIT 21 July....

Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 19 July 2020.
Melt STILL very much the same as 3rd June to 18 July. Melt higher at 36.8% of the surface area of Greenland, and still very much above average.
But Precipitation up somewhat.
The result was a daily SMB loss of 5.8 4.8 GT, at about the average for this day.

Note that we are now, on average,  at the peak of daily SMB losses.

Precipitation still looks as if it may be low for much of the next 5 to 10 days.
Melt looks possibly to be up a bit more today (Monday), then increasing Tuesday Wednesday and (this is a change) staying high for at least several days after that.

So we just might see some above average SMB loss days during this next week, (and perhaps even beyond).

SMB gain for this year to date is at 417 GT, a bit less than 40 50 GT above the average for the year-end (31 August) of about 380 370 GT**. It is very probable that SMB gain for the year will end up below average - but by how much?

** Had another look at the DMI graph and average SMB gain in a year looks more like 370 Gt, not 380 GT.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 21, 2020, 12:30:42 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 20 July 2020.
Melt STILL very much the same as 3rd June to 19 July. Melt higher at 37.5% of the surface area of Greenland, and still very much above average.
But Precipitation up somewhat more than I expected.
The result was a daily SMB loss of 5.4 GT, a bit above the average for this day.

Note that we are now, on average,  at the peak of daily SMB losses.

Precipitation looks as if it may be very low until Friday, then higher from Saturday.
Melt looks possibly to be up a bit more today (Tuesday), then increasing Wednesday and staying high for a few days after that. On Sunday GFS says considerable melt in the North. After that looks like melt moderating.

So we just might see some above average SMB loss days during this week, (but not beyond ?).

SMB gain for this year to date is at 411 GT, about 40 GT above the average for the year-end (31 August) of about 370 GT. It is very probable that SMB gain for the year will end up below average - but by how much?
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 22, 2020, 11:55:09 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 21 July 2020.
Melt STILL very much the same as 3rd June to 20 July. Melt higher at 41.8% of the surface area of Greenland, and 2nd highest for the year.
AND Precipitation low.
The result was a daily SMB loss of 6.8 GT, well above the average for this day and highest for the year to date.

Just for once things turned out on this day pretty much as expected.
Note that we are now, on average,  at the peak of daily SMB losses.

Precipitation looks as if it may be very low until Friday, then higher from Saturday.
Melt looks possibly to be and staying high for a few more days after that. For Sunday GFS says considerable melt in the North. After that looks like melt moderating.

So we just might see some above average SMB loss days during this week, (but not beyond ?).

SMB gain for this year to date is at 404 GT, somewhat above 30 GT above the average for the year-end (31 August) of about 370 GT.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 23, 2020, 01:12:44 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 22 July 2020.
Melt STILL very much the same as 3rd June to 21 July. Melt higher at 42.75% of the surface area of Greenland, and highest for the year.
AND Precipitation low.
The result was a daily SMB loss of 7.3 GT, well above the average for this day, and highest for the year to date.

Precipitation looks as if it may be low until Friday, then a little bit higher from Sunday.
Melt looks possibly to be high for a few more days more. For Sunday to Tuesday GFS says considerable melt in the North. After that looks like melt moderating.

So we just might see some above average SMB loss days until next Tuesday, (but not beyond ?).

SMB gain for this year to date is at 397 GT, perhaps less than 30 GT above the average for the year-end (31 August) of about 370 GT.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 24, 2020, 12:16:53 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 23 July 2020.
Melt STILL very much above average as it has been since early June.
On this day melt very high 42.45% of the surface area of Greenland, and 2nd highest for the year.

AND Precipitation low.

The result was a daily SMB loss of 6.8 GT, well above the average for this day.

Precipitation looks as if it may be a little bit higher from Sunday.
Melt looks possibly to be high for a few more days more.
After that looks like melt moderating but maybe still above average.

So we just might see some above average SMB loss days for some time more..

SMB gain for this year to date is at 390 GT, a bit more than 20 GT above the average for the year-end (31 August) of about 370 GT.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 25, 2020, 01:48:17 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 24 July 2020.
Melt STILL very much above average as it has been for such a long time.
On this day melt unchanged, very high at 42.45% of the surface area of Greenland, and 2nd highest for the year.

AND Precipitation a bit above average.

The result was a daily SMB loss of 5 GT, at the average for this day.

Precipitation looks as if it may be a little bit higher from Today until Tuesday, and just maybe dryer after that.
Melt looks possibly to be high for a few more days more.
After that looks like melt moderating but maybe still above average.

So we just might (or might not) see some above average SMB loss days for some time more..

SMB gain for this year to date is at 385 GT, a bit less than 20 GT above the average for the year-end (31 August) of about 370 GT.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 26, 2020, 05:03:16 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 25 July 2020.
Melt STILL very much above average as it has been for such a long time.
On this day melt down a bit, still very high at 40.3% of the surface area of Greenland.

AND Precipitation well above average.

The result was a daily SMB loss of 2.2 GT, well below the average for this day. A good demonstration that high SMB loss needs high melt plus low precipitation.

Precipitation looks as if it may be a little bit higher from Today until Tuesday, and just maybe dryer after that. But the forecasts seem to vary muchly from day to day.
Melt looks possibly to be high for a few more days more.
After that looks like melt moderating but maybe still above average.

So we just might (or might not) see some above average SMB loss days for some time more..

SMB gain for this year to date is at 383 GT, a bit less than 20 GT above the average for the year-end (31 August) of about 370 GT.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 27, 2020, 07:48:07 PM
Tomorrow is another day....
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 28, 2020, 12:44:17 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 27 July 2020.
Melt STILL very much above average as it has been for such a long time.
On this day melt  at 41.3% of the surface area of Greenland.

AND Precipitation again above average.

The result was a daily SMB loss of 2.9 GT, well below the average for this day. Another good demonstration that for many days this season despite high melt, above average precipitation has meant below average SMB losses.

Precipitation looks as if it may be a little bit high today (Tuesday), and just maybe dryer after that. Melt looks possibly to be high but not as high as now for a few more days more.

So we just might (or might not) see some above average SMB loss in the next few days.

SMB gain for this year to date is at 378 GT, about 10 GT above the average for the year-end (31 August) of about 370 GT.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 29, 2020, 02:24:05 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 28 July 2020.
Melt STILL very much above average as it has been for such a long time.
On this day melt  at 41.4% of the surface area of Greenland.

AND Precipitation again above average.

The result was a daily SMB loss of 1.8 GT, well below the average for this day. Another good demonstration that for many days this season despite high melt, above average precipitation has meant below average SMB losses.

Precipitation looks as if it may be less in the next few days after that. But......
Melt looks possibly to be high but not as high as now for a few more days more.

So we just might (or might not) see some above average SMB loss in the next few days.

SMB gain for this year to date is at 376 GT, about 10 GT above the average for the year-end (31 August) of about 370 GT.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: lurkalot on July 30, 2020, 12:09:52 PM
Thank you Gerontocrat for all your meticulous analyses. This one puzzles me, however. If the precipitation is snow then I understand the analysis. But if it is rain surely this will tend to increase the melt rather than counteract it. My apologies if this has been raised before.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 30, 2020, 05:43:10 PM
If the precipitation is snow then I understand the analysis. But if it is rain surely this will tend to increase the melt rather than counteract it. My apologies if this has been raised before.
Not a problem...
Quote from DMI
Quote
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. See further discussions of the difference between surface mass balance and melting here.

BUT.. there is a paper somewhere talking about how increased rain events (even in winter!) must in the end cause greater run-off. The run-off is part of the DMI model that calculates SMB loss or gain.  I bet there are heated discussions about the rain, and rain + surface melting percolating through the ice sheet to bedrock and finding its way to the ocean.

You will see from the SMB map how few meteo stations there are on Greenland, and even so it is better than it was. Lack of field observations limits the ability to test models against reality = the story of the Arctic and even more so in the Antarctic.

Meanwhile.....
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 29 July 2020.
Melt STILL very much above average as it has been for such a long time.
But on this day melt is down to 37.6% from 41.4% of the surface area of Greenland.

AND Precipitation lower than ysterday.

As a result was a daily SMB loss increased to 4.3 G from 1.8 GT, average for this day. This time a demonstration of how a lower precipitation has more effect than a lower melt on SMB loss.

Precipitation looks as if it may be less in the next few days but......
Melt looks possibly to be high but not as high as now for a few more days more.

So we just might (or might not) see some above average SMB loss in the next few days.

SMB gain for this year to date is at 372 GT, a few GT above the average for the year-end (31 August) of about 370 GT. (see smb-graph)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on July 31, 2020, 12:06:39 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 30 July 2020.
Melt STILL very much above average as it has been for such a long time.
But on this day melt is down to 36.5% from 37.6% of the surface area of Greenland.

AND Precipitation lower than yesterday.

As a result was a daily SMB loss increased again to 4.85 G from 4.3 GT, above average for this day. Another demo of how a lower precipitation has more effect than a lower melt on SMB loss.

Precipitation looks as if it may be less in the next few days and rain at low altitudes but......
Melt looks possibly to be high but not as high as now for a few more days more.

So we just might (or might not) see some above average SMB loss in the next few days.

SMB gain for this year to date is at 367 GT, 1 or 2 GT above the average for the year-end (31 August) of about 365 GT. (see smb-graph).
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 01, 2020, 02:19:09 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 31 July 2020.
Melt STILL very much above average as it has been for such a long time.
But on this day melt is down to 33% from 36.5% of the surface area of Greenland.

AND Precipitation perhaps the same as yesterday.

As a result was a daily SMB loss decreased to 4.5 G from 4.8 GT, at average for this day.

Precipitation looks as if it may be less in the next few days and rain at low altitudes but......
Melt looks possibly to be high but not as high as now for a few more days more.

So we just might (or might not) see some above average SMB loss in the next few days.

SMB gain for this year to date is at 363 GT, about 1 or 2 GT below the average for the year-end (31 August) of about 365 GT.
__________________________________
The accumulated SMB anomaly graph shows clearly the East / West divide between above / below average SMB gain.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 02, 2020, 11:30:28 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 31 July 2020.
Melt Very much above average as it has been for such a long time, but perhaps on a slow decline.
On this day melt is down to 31% from 33% of the surface area of Greenland.

AND Precipitation perhaps higher than yesterday.

As a result was a daily SMB loss decreased to 1.85 G from 4.5 GT, below average for this day.

Precipitation no longer looks as if it may be less in the next few days, but with rain at low altitudes,
Melt looks possibly to be high but not as high as now for a few more days more.

So my guess is the chances are that we won't see some above average SMB loss in the next few days.

SMB gain for this year to date is at 361 GT, a bit below the average for the year-end (31 August) of about 365 GT.
__________________________________
One year ago, in the 3 days from 31/7/2019 to 1/8/2019, SMB loss was over 30GT, i.e. more than 10GT per day. It was warm, melt exceeded 55% on the 1st August and it was also DRY.

This year the same 3 days saw of loss of lust over 11GT, i.e. an average of less than 4GT.
It was warm, melt well above average, but it was NOT DRY.

Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 03, 2020, 12:12:35 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 2 Aug 2020.
Melt Very much above average as it has been for such a long time, but perhaps on a slow decline.
On this day melt is unchanged at 31% of the surface area of Greenland.

AND Precipitation perhaps lower than yesterday.

As a result was a daily SMB loss increased to 2.5 GT from 1.85 GT, below average for this day.

Precipitation no longer looks as if it may be less in the next few days, but with rain at low altitudes,
Melt looks possibly to be high but not as high as now for the next 3-5 days, and just maybe a spike in melt Sat 8th to Mon 10th.

So my guess is the chances are that we won't see many above average SMB losses in the next few days.

SMB gain for this year to date is at 358 GT, a bit below the average for the year-end (31 August) of about 365 GT.
__________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: GG77 on August 08, 2020, 07:46:52 AM
gerontocrat - where have you gone, i enjoy reading your posts about Greenland.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on August 09, 2020, 09:28:53 AM
He had trouble with his laptop...
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: grixm on August 09, 2020, 09:44:34 AM
Looks like Greenland had close to its first day since spring of SMB gain
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: Altai on August 09, 2020, 09:46:39 AM
http://polarportal.dk/fileadmin/polarportal/surface/SMB_combine_SM_day_EN.png
No smb loss at the moment due to high precipitation.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 on August 12, 2020, 12:22:58 AM
SMB gain in mid august, I don't think that happens very often!
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on August 12, 2020, 04:08:19 AM
Well surprisingly we could finish the year with near-average SMB change. I would never have guessed it a month ago.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 16, 2020, 01:38:59 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 15 Aug 2020.
While I've been out of action for this month...

Melt has declined from a very much above average 30% to the 15 Aug value of 19.5%

Precipitation has been sometimes been very high.

As a result there were daily SMB gains from the 9th to the 14th August as opposed to the "normal" losses. Cumulative SMB gain for the year is 362 GT, a bit below the average for the year-end (31 August) of about 365 GT.

This near average SMB gain figure conceals high melt and high precipitation as can be seen in the accumulated SMB anomaly map (last image)

However, if GFS has got it right, Monday to Friday will see a return to high melt, and precipitation will be low. Maybe some late season SMB losses?
_______________________________________
click each image for full-size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: interstitial on August 16, 2020, 03:29:20 PM
I am glad you got a new laptop Gerontocrat. I like so many others have missed the data.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 17, 2020, 01:19:56 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 16 Aug 2020.

Melt increased a little to 20.7% from the 15 Aug value of 19.5%, a bit above average for this date.

Precipitation high again.

The result is a daily SMB small gain of 0.65 GT as opposed to an average small loss. Cumulative SMB gain for the year is 362 GT, a bit below the average for the year-end (31 August) of about 365 GT.

GFS is still saying that Monday to Friday will see a return to high melt, and precipitation will be low. Maybe some late season SMB losses?
_______________________________________
click each image for full-size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: FrostKing70 on August 18, 2020, 11:23:47 PM
What a difference a few days can make!  Hard to believe this year closed the gap to the mean!
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: VeliAlbertKallio on August 19, 2020, 03:41:13 AM
This would suggest me the west Greenland losing from additional climatic warming to the gain of east Greenland. Western winds carrying less humidity as they arrive from the continent, while the warmer Atlantic water body having more moisture, increasing precipitation. But once ice-free ocean in the north materialises early in insolation, we will see this set up crumbling and more melting everywhere.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 19, 2020, 09:30:51 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 18Aug 2020.

Melt increased in the last 2 days to 24.4% from the 16 Aug value of 20.7%, above average for this date.

Precipitation somewhat lower..

The result is #daily SMB losses of 2.8 & 3.5 GT on the 2 days, somewhat above average. Cumulative SMB gain for the year is down to 356 GT, approaching 10GT below the average for the year-end (31 August) of about 365 GT.

GFS is still saying that from now to Friday will see a continuation high melt, and precipitation will be low. Maybe some more late season SMB losses?
_______________________________________
click each image for full-size.

& a gif to click to show how August has seen lots of melt but lots of precipitation.
(Playtime on the new computer)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 20, 2020, 09:46:02 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 19 Aug 2020.

Melt increased  to 28% from the 18 Aug value of 24.4%, above average for this date.

Precipitation low,

The result is a daily SMB losses of 2.9 GT, somewhat above average. Cumulative SMB gain for the year is down to 353 GT, just more than 10GT below the average for the year-end (31 August) of about 365 GT.

GFS is still saying that today and Friday will see a continuation of high melt, and precipitation will be low. Maybe some more late season SMB losses?

After that melt will moderate considerably, while precipitation may be quite low and confined to northern Greenland, arriving all the way from Western Russia.(says GFS)

_______________________________________
click each image for full-size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: crandles on August 20, 2020, 07:12:55 PM
Return to rapid ice loss in Greenland and record loss in 2019 detected by the GRACE-FO satellites

https://www.nature.com/articles/s43247-020-0010-1

(https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs43247-020-0010-1/MediaObjects/43247_2020_10_Fig1_HTML.png)

Quote
Between 2003-2016, the Greenland ice sheet (GrIS) was one of the largest contributors to sea level rise, as it lost about 255 Gt of ice per year. This mass loss slowed in 2017 and 2018 to about 100 Gt yr−1. Here we examine further changes in rate of GrIS mass loss, by analyzing data from the GRACE-FO (Gravity Recovery and Climate Experiment – Follow On) satellite mission, launched in May 2018. Using simulations with regional climate models we show that the mass losses observed in 2017 and 2018 by the GRACE and GRACE-FO missions are lower than in any other two year period between 2003 and 2019, the combined period of the two missions. We find that this reduced ice loss results from two anomalous cold summers in western Greenland, compounded by snow-rich autumn and winter conditions in the east. For 2019, GRACE-FO reveals a return to high melt rates leading to a mass loss of 223 ± 12 Gt month−1 during the month of July alone, and a record annual mass loss of 532 ± 58 Gt yr−1.


BBC is saying "breaking the previous record by 15%". 532 compared to 2012's 437 is over 21%. that 437 is a 2 year period.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: sidd on August 20, 2020, 11:08:00 PM
Thats a good paper, i am glad to see they resolved the discrepancy noted in an earlier paper this year from Velicogna et al (ref 14 in the paper citd above ...)

sidd
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 21, 2020, 02:00:19 PM
Thats a good paper, i am glad to see they resolved the discrepancy noted in an earlier paper this year from Velicogna et al (ref 14 in the paper citd above ...)

sidd
It was Ingo Sasgen (lead writer?) who first made sure I could get the GIS and AIS GRACE-FO data files down to basin level, now easily found at http://gravis.gfz-potsdam.de/greenland. Definitely one of the good guys who wants to share his knowledge & data (unlike the Mosaic Project bosses?)

Meanwhile, data from...
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 20 Aug 2020.

Melt increased to 33.4% of the surface area of Greenland from 28% the day before, well above average for this date.

Precipitation quite low,

The result is a daily SMB losses of 3.5 GT, well above average for this date. Cumulative SMB gain for the year is down to 350 GT, perhaps 15 GT below the average for the year-end (31 August) of about 365 GT.

GFS is still saying that Friday (today) will see a continuation of high melt, and gradually moderating after that. GFS also says that precipitation will be low for the next few days. Maybe some more late season SMB losses, albeit of a more modest nature?

_______________________________________
click each image for full-size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 21, 2020, 09:56:08 PM
Thats a good paper, i am glad to see they resolved the discrepancy noted in an earlier paper this year from Velicogna et al (ref 14 in the paper citd above ...)

sidd
The media have seized on this paper. Even bloomberg news have made a big thing of it.
Ingo tells me that he is inundated with media requests.

https://www.bloomberg.com/news/articles/2020-08-21/global-warming-is-melting-greenland-s-ice-sheet-causing-sea-rise?srnd=premium-europe

ps: High GIS mass loss in 2019? - You saw it first on this thread
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 22, 2020, 02:03:03 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 21 Aug 2020.

Melt down a tad to 33% of the surface area of Greenland from 33.4% the day before, very much above average for this date.

Precipitation quite low,

The result is a second daily SMB loss of 3.5 GT, well above average for this date, amye even in record territory.. Cumulative SMB gain for the year is down to 346 GT, approaching 20 GT below the average for the year-end (31 August) of about 365 GT.

GFS is still saying from now melt will gradually reducet. GFS also says that precipitation will be low for the next few days. Maybe some more late season SMB losses, albeit of a more modest nature?

_______________________________________
click each image for full-size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 23, 2020, 03:11:07 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 22 Aug 2020.

Melt down a tad to 28% of the surface area of Greenland from 33% the day before, very much above average, perhapd even in record territory, for this date.

Precipitation low,

The result is a daily SMB loss of 2.8 GT, well above average for this date, maybe even in record territory.. Cumulative SMB gain for the year is down to 343 GT, about 20 GT below the average for the year-end (31 August) of about 365 GT.

GFS is still saying from now gradually lower temperatures imply melt will gradually reduce. GFS also says that precipitation will be low for the next few days. Maybe some more late season SMB losses, albeit of a more modest nature?

_______________________________________
click each image for full-size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 24, 2020, 11:47:54 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 23 Aug 2020.

Melt down to 20.4% of the surface area of Greenland from 28% the day before, which is still above average for this date.

Precipitation up a bit.

The result is a daily SMB loss of 0.8 GT, still above average for this date. Cumulative SMB gain for the year is down to 342 GT, a bit more than 20 GT below the average for the year-end (31 August) of about 365 GT.

GFS is still saying from now lower temperatures, implying melt will gradually reduce. GFS also says that precipitation will be low for the next few days. Maybe some more late season SMB losses, albeit of a more modest nature?

_______________________________________
click each image for full-size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 25, 2020, 03:58:11 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 24 Aug 2020.

Melt down to 17.3% of the surface area of Greenland from 20.4% the day before, which is still above average for this date.

Precipitation average?.

The result is a small daily SMB loss of 0.4 GT, still above average for this date. Cumulative SMB gain for the year is down to 342 GT, a bit more than 20 GT below the average for the year-end (31 August) of about 365 GT.

GFS is still saying from now lower temperatures, implying melt will gradually reduce. However, chance of a blip upwards in temperatures on Friday, subsiding by Sunday. GFS also says that precipitation will be low for the next few days, confined to the NW corner.After that ??.

Maybe some more late season SMB losses this week, albeit of a more modest nature?

________________________________________
Note that the DMI starts a new year on 1st September for SMB data, despite that melt certainly can be significant at least in the first half of the month. So I will keep the thread open and extend the graphs until...?
AGW is such a nuisance.
_______________________________________
click each image for full-size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 26, 2020, 02:16:01 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   

Data as at 25 Aug 2020.

Melt down to 12.3% of the surface area of Greenland from 17.3% the day before, which is average for this date.

Precipitation above average?.

The result is a daily SMB gain of 1.3 GT, well above average for this date. Cumulative SMB gain for the year is 343 GT, a bit more than 20 GT below the average for the year-end (31 August) of about 365 GT.

GFS is still saying from now lower temperatures, implying melt will gradually reduce. However, increasing chance of a blip upwards in temperatures on Friday, now lasting to Monday. GFS also says that precipitation will be confined to the NW corner for the next few days. But after that ??.

Now it looks like the last few days of August could see some above average melt, but precipitation could still mean SMB gain.

________________________________________
click each image for full-size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 27, 2020, 12:54:34 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   

Data as at 26 Aug 2020.

Melt down to 10.8% of the surface area of Greenland from 12.3% the day before, which is average for this date.

Precipitation above average?.

The result is a daily SMB gain of 2.35 GT, well above average for this date. Cumulative SMB gain for the year is 345 GT, 20 GT below the average for the year-end (31 August) of about 365 GT.

GFS is still saying from now to Friday lower temperatures, implying melt will gradually reduce. However, increasing chance of a blip upwards in temperatures on Saturday to Monday. GFS also says that precipitation will be confined to the NW corner for the next few days. But after that ??.

Now it looks like the last few days of August could see some above average melt, but precipitation could still mean SMB gain.

GFS also hinting at an Indian Summer but spells of significant precipitation in early September.

________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 28, 2020, 11:51:47 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   

Data as at 27 Aug 2020.

Melt pretty much unchanged at 10.75% of the surface area of Greenland from 10.8% the day before, which is average for this date.

Precipitation above average?.

The result is a daily SMB gain of 1.4 GT, above average for this date. Cumulative SMB gain for the year is 347 GT, a bit less than 20 GT below the average for the year-end (31 August) of about 365 GT.

GFS is now saying Friday (28 Aug) is seeing a temperature uplift, implying melt may be considerably higher. This increased melt may persist though by not so much until Monday.
GFS also says that this increase in melt will be accompanied by a mixture of rain and snow from the south.

We may be seeing a continuation of the season so far to the end of the season- i.e. high melt + high precipitation.

GFS reliability seems to be getting somewhat less - change of season wobbles?
________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 29, 2020, 11:33:21 AM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   Looks more and more like it.

Data as at 28 Aug 2020.

Melt Friday's higher temperatures meant a small uptick in melt to 12.3% of the surface area of Greenland from 10.75% the day before, which is a bit above average for this date.

Precipitation above average?.

The result is a daily SMB small gain of 0.7 GT, above average for this date. Cumulative SMB gain for the year is 348 GT, a bit less than 20 GT below the average for the year-end (31 August) of about 365 GT.

This increased melt may persist though by not so much until Monday.
GFS also says that this increase in melt will be accompanied by a mixture of rain and snow from the south. After that melt looks like continuing at a modest amount for a few days more.

GFS reliability seems to be getting somewhat less - change of season wobbles?
________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 30, 2020, 01:33:31 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   Looks more and more like it.

Data as at 29 Aug 2020.

Melt down a tad to 11.9% of the surface area of Greenland from 12.3% the day before, which is a bit above average for this date.

Precipitation well above average.
The result is a daily SMB large gain of 3.1 GT, well above average for this date, looking close to record territory.

Cumulative SMB gain for the year is 351 GT, merely 15 GT below the average for the year-end (31 August) of about 365 GT.

Melt may persist though reduced into early September
GFS also says that this melt will be accompanied by a procession of lows bringing a mixture of rain and snow from the south.

SMB gains - maybe some large - in prospect.

This season has brought well above average melt, but very few dry days. Although melt this year looks higher overall than last year (2018-19),  SMB gain is currently 180 GT greater than last year, although on 1st May 2020 SMB gain was only 10 GT above 2019.

Why? Precipitation. This year the blocking high over Greenalnd was insufficient to prevent weather systems dumping precipitation on Greenland. A very average result for the year end concealing a lot of high energy weather?
_________________________________________________________________
(It seems that in 2012 the melt season was characterised by the combination of high melt and very low precipitation, which led to the record low SMB gain for the year. Spectacular Greenland blocking high?).
________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on August 31, 2020, 12:08:28 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   Looks more and more like it.

Data as at 30 Aug 2020.

Melt down a tad to 11.4% of the surface area of Greenland from 11.9% the day before, which is a bit above average for this date.

Precipitation low(ish).
The result is a daily SMB small loss of 0.6 GT, as opposed to an average small gain on this day.

Cumulative SMB gain for the year is 350 GT, merely 15 GT below the average for the year-end (31 August) of about 365 GT.

Melt may persist though reduced into early September.
GFS also says that this melt will be accompanied by a procession of lows bringing a mixture of rain and snow from the south.

SMB gains - maybe some large - in prospect.

This season has brought well above average melt, but very few dry days.
_________________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on September 01, 2020, 02:31:33 PM
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   Looks more and more like it.
Anyway it is the end of the DMI year.

Data as at 31 Aug 2020.

Melt down a tad to 9.5% of the surface area of Greenland from 11.4% the day before, which is a about average for this date.

Precipitation low(ish).
The result is a daily SMB small loss of 0.5 GT, as opposed to an average small gain on this day.

Cumulative SMB gain for the year is just below 350 GT, merely 15 GT below the average for the year-end (31 August) of about 365 GT.

Melt may persist though reduced into early September.
GFS also says that this melt will be accompanied by a procession of lows bringing a mixture of rain and snow from the south.

SMB gains - maybe some large - in prospect.

This season has brought well above average melt, but very few dry days.

Although it is the end of the year as far as DMI is concenrned, I will keep the Melt and SMB graphs from my spreadsheet open for a bit longer.
_________________________________________________________________
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: oren on September 02, 2020, 06:57:46 AM
It's been a weird August with lots of precipitation and the accumulated SMB line refusing to drop. However I wonder if, while more melt and more precipitation in tandem equal a stable SMB number, if they also equal a stable ice mass loss. Higher surface melt could also mean faster discharge and faster marine melting.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on September 02, 2020, 01:52:31 PM
It's been a weird August with lots of precipitation and the accumulated SMB line refusing to drop. However I wonder if, while more melt and more precipitation in tandem equal a stable SMB number, if they also equal a stable ice mass loss. Higher surface melt could also mean faster discharge and faster marine melting.
Add to that a steaming Baffin Sea.

I've only got GRACE-FO GIS mass change by basin to May 2020 from GFZ.
The GRACE-FO data from JPL is a simple text file of the total mass change only. It's to June 2020. Should get July by the 10th of this month.

But I spotted an inconsistency between the two sets of data too big to be ignored, so I told GFZ.
Last I heard was that the mathematicians etc were re-examining the hairy calculations used to try and resolve the problem. So maybe new data will be delayed. Bummer.


Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on September 03, 2020, 08:53:29 PM
GIS - SMB + Total Mass Loss.

JPL issued the July 2020 data today. It's total mass loss for the GIS only, not down to basin level.

So now one can see the GIS mass loss for this July is less than in July 2019, mostly due to lower SMB losses.

Looks much better if you click the image for full size.
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on September 14, 2020, 11:03:39 PM
And GFZ have just updated their GRACE-FO data to July - so here are the graphs .
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on September 20, 2020, 11:03:15 PM
NSIDC Greenland Today have produced  a nearly end-of-season report

https://nsidc.org/greenland-today/
Greenland’s 2020 summer melting: a new normal?
FEATURED August 12, 2020
Melting through the peak of Greenland’s summer melt season has been well above the 1981 to 2010 average, but below the levels of many previous summers of the past decade. While the northeast and southwest areas of the ice sheet had significantly more melt than average, the melt extent over the southeast and northwest coasts was lower than average. The 2020 surface runoff to date is lower than in recent years.

(https://nsidc.org/greenland-today/images/greenland_daily_melt_tmb.png)

(https://nsidc.org/greenland-today/images/greenland_cumulative_melt_tmb.png)

(https://nsidc.org/greenland-today/images/greenland_daily_melt_plot_tmb.png)
Title: Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
Post by: gerontocrat on September 24, 2020, 01:54:22 PM
2020 SMB + Melt from June to Sept 22

A LARGE GIF


click to play, or you can download it by clicking on the filename below the image and then run it offline on an app of your choice.