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.