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gerontocrat

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Greenland 2023-24 SMB, melting and GRACE mass
« on: November 05, 2023, 10:36:33 AM »
Until the 2024 melt gets going around April 2024, this thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data.

SMB gain as at 4 November is 163 GT, 23 GT (16%) above the 2017-2022 average, which is also well above the longterm average from DMI.

Wetter than average conditions are largely confined to the coast, especially in the SE.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #1 on: November 11, 2023, 06:53:34 PM »
GFZ have updated the GIS Mass Loss monthly data to mid-June 2023. (Note that GFZ and JPL-NASA both go mid-month to mid-month)

The hiatus in GIS Mass Loss continues (see next post).
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #2 on: November 11, 2023, 07:30:00 PM »
There is a hiatus in GIS Mass Loss

GIS Mass Loss is
the sum of calving + basal melting of marine-terminating glaciers + melting at the boundary between the ice sheet and the ice sheet from friction and freshwater intrusion from above (e.g. via moulins)

minus SMB gain or plus SMB loss. We have SMB data from the DMI.

This year SMB gains were high (lots of snowfall), and melting did not really take off until after mid-June. This is shown on the attached graph.

When we get GIS Mass Loss data for mid-June to mid-August we may see big monthly losses as melt was high (see 2nd graph).
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #3 on: November 25, 2023, 07:09:17 PM »
Until the 2024 melt gets going around April 2024, this thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

SMB gain as at 24 November is 206 GT, 18 GT (10%) above the 2017-2022 average, which is also above the longterm average from DMI.

Wetter than average conditions are largely confined to the coast, especially in the SE.

i.e. not a lot going on.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #4 on: December 10, 2023, 02:33:17 PM »
Until the 2024 melt gets going around April 2024, this thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

SMB gain as at 9 December is 235 GT, 9 GT (4%) above the 2017-2022 average, which is also above the longterm average from DMI, but well below the 2022-3 SMB gain by this date.

Wetter than average conditions are largely confined to the coast, especially in the SE.

i.e. not a lot going on.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #5 on: December 10, 2023, 02:49:23 PM »
However JPL/NASA have added another 3 months of Greenland Ice Sheet Mass data - to mid-September 2023.

In those 3 months Greenland lost 350GT of mass. During those 3 months surface melt in Greenland was well above average, and overall SMB loss was 160GT for those 3 months.

Nevertheless, overall SMB gain for the 12 months to September 2023 was nearly 400GT, which is a very large brake on Greenland Ice Sheet Mass Loss.

Climate science suggests that a warmer wetter Greenalnd will increase snowfall but also increase rain on snow events and more above freezing days at low altitude. Initially this may increase annual SMB gains until warmth overpowers increases in snow. When? "aye, there's the rub".
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #6 on: January 09, 2024, 02:23:01 PM »
JPL/NASA have added another 3 months of Greenland Ice Sheet Mass data - to mid-October 2023.

There was a small mass gain of 15 GT in that month, made up of a 55GT mass gain in SMB and a 40GT mass loss of 40GT from marine-terminating laciers calving & melting.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #7 on: January 27, 2024, 06:49:10 PM »
Until the 2024 melt gets going around April 2024, this thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

SMB gain as at 26 Jan 2024 is 327 GT, 10 GT (3%) above the 2017-2022 average of 317 GT, which is a little below the longterm average from DMI.

Melt viirtually zero

i.e. not a lot going on.
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #8 on: February 09, 2024, 07:10:49 PM »
GFZ have at last produced another update of GIS Mass Loss, this time to October 2023.
The data includes mass loss by 8 drainage basins, which I have also grouped into 3 regions.

Some of the graphs attached have blank spaces where monthly data was not produced by the first GRACE satellites.

Total Mass Loss since early 2002 is 4,635 GT, about 220 GT a year.

Perhaps the most interesting feature is that Mass Loss in Drainage Basin 306 that fronts the southern half of Baffin Bay has basically stalled since late 2019. Until then Mass Loss was occurring at the highest rate of all the basins. We do not have SMB data from DMI by drainage basins, though they hope one day to be able to produce it. If we had it we would be able to get at least an idea if the stall in Mass Loss of that basin is due to increased SMB (i.e. snowfall) and / or reduced calving and melt of marine-terminating glaciers.

Meanwhile Mass Loss in basin 307 that fronts the Northern half of Baffin Bay and Basin 304 in SE Greenland continues unabated.

Overall, Mass Loss is higher in West Greenland.

ps: Processing GRACE-FO data is a complex business that chews up people and super-computer time. GFZ tells me that this year and next year they have funding to produce more frequent and more-up-to-date analyses. Let's also hope that DMI get the resources they need to develop their capabilities as well.
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #9 on: February 18, 2024, 11:34:33 AM »
Until the 2024 melt gets going around April 2024, this thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

SMB gain as at 17 Feb 2024 is 354 GT, 5 GT (1%) below the 2017-2022 average of 359 GT, which is below the longterm average from DMI.

Melt virtually zero

i.e. not a lot going on.
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Renerpho

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #10 on: February 18, 2024, 05:59:05 PM »
Total Mass Loss since early 2002 is 4,635 GT, about 220 GT a year.

https://svs.gsfc.nasa.gov/31156/ gives a total loss of about 5,500 GT, and an average of 271 GT per year. I don't know anything about this data product, but I am confused by the difference. Do you know what's going on?
It is no good trying to stop knowledge from going forward. Ignorance is never better than knowledge. -- Laura Fermi (sic!) https://en.wikiquote.org/wiki/Talk:Enrico_Fermi#Unsourced

gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #11 on: February 18, 2024, 07:11:40 PM »
Total Mass Loss since early 2002 is 4,635 GT, about 220 GT a year.

https://svs.gsfc.nasa.gov/31156/ gives a total loss of about 5,500 GT, and an average of 271 GT per year. I don't know anything about this data product, but I am confused by the difference. Do you know what's going on?
The calculation by JPL to Nov 23 is GIS mass loss of 5,525 GT while the calculation by German Research Centre for Geosciences (GFZ) is 4,635.

About a year or so ago I asked GFZ about the differences (much higher for the GIS than the AIS). GFZ said they both start from the same place - raw data from the GRACE satellites.

Then the data is processed by JPL using JPL's algorithm, and by GFZ using GFZ's algorithm, Glacial Isostatic Adjustment (GIA) being the major change.

GFZ basically said they had confidence in their model. You can read about it here: http://gravis.gfz-potsdam.de/corrections

But they did say recently that this year and next year they had funding to do development work on the GRACE-FO based systems they have ( see http://gravis.gfz-potsdam.de/gis)

I am using JPL's data for integration with SMB data from DMI.
But the JPL product does not have analyses by basins (despite a promise long ago), so I use GFZ data for the basin analyses

So no real explanation

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Renerpho

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #12 on: February 18, 2024, 07:19:35 PM »
So no real explanation

Interesting, thank you! Maybe the additional funding will help not just improve the model (as well as the final data product), but also look at possible problems with it. This is something all complex models should be subjected to, but as you said previously, working on this data is hard and expensive. On the plus side, having two independent products from the same raw data that differ by ~20% gives an indication of what kind of uncertainty there probably is in each number. Greenland ice is decreasing by 200-300 GT per year.

P.S. Congratulations for making your 20,000th post.  :)
It is no good trying to stop knowledge from going forward. Ignorance is never better than knowledge. -- Laura Fermi (sic!) https://en.wikiquote.org/wiki/Talk:Enrico_Fermi#Unsourced

gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #13 on: February 18, 2024, 07:44:12 PM »
P.S. Congratulations for making your 20,000th post.  :)
20,000? scary.
That wasn't the idea when I started to post on the ASIF
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #14 on: March 19, 2024, 03:16:49 PM »
Until the 2024 melt gets going around April 2024, this thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

SMB gain to date as at 18 March 2024 is 429 GT, 9 GT (2%) above the 2017-2022 average of 420 GT, which is about 20 GT below the longterm average from DMI.

Melt virtually zero

i.e. still not a lot going on.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #15 on: March 23, 2024, 09:18:10 PM »
JPL has issued Greenland ice sheet mass loss data to Dec 2023

A modest mass increase of 4GT in December, total mass loss 2002 to date 5,525GT. The monthly SMB gain was 71 GT, meaning mass loss from glaciers was 66 GT, mainly due to calving and melt from marine terminating glaciers.
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #16 on: April 10, 2024, 11:04:12 PM »
Until the 2024 melt gets going usually sometime in late April 2024, this thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

SMB gain to date as at 18 March 2024 is 450 GT, 10 GT (2%) below the 2017-2022 average of 460 GT, and around 40 GT below the longterm average from DMI.

Melt virtually zero

i.e. still not a lot going on.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #17 on: April 14, 2024, 12:17:32 PM »
https://gravis.gfz-potsdam.de/gis
GFZ have released another 2 months GIS mass loss data - to Dec 23

In 2023, the GIS lost 232GT, of which 87GT was in the South, and 69GT in the West.

click images to enlarge
« Last Edit: April 14, 2024, 12:25:38 PM by gerontocrat »
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #18 on: April 22, 2024, 12:23:10 PM »
Until the 2024 melt gets going usually sometime in late April 2024 (see below) this thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

SMB gain to date as at 21 April 2024 is 466 GT, 29 GT (6%) below the 2017-2022 average of 495 GT, and around 50 GT below the longterm average from DMI.

Melt in the last week has been measurable but very much below the average. However, it looks likely that more significant melt is likely on most days during the next week to 10 days.

i.e. First signs of the melt season waking up..
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #19 on: April 25, 2024, 10:18:36 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
In the last few days Spring has moved North into Southern Greenland bringing warmth and wet

SMB gain to date as at 24 April 2024 is 479 GT, 21 GT (4%) below the 2017-2022 average of 500 GT, and around 40 GT below the longterm average from DMI. This is after 2 days of significant precipitation on the 23rd & 24th April.

The first meaningful Melt of the season happened on the same two days, a week or two later than average. It looks likely that measurable melt is likely on most days during the next week.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #20 on: April 25, 2024, 10:59:48 PM »
JPL has released another month of GIS mass loss data - to Jan24

A very small decrease in Mass Loss due to low increase in SMB
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #21 on: May 03, 2024, 10:20:14 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
In the last week or so Spring moved North into Southern Greenland bringing warmth and wet, but may have now retreated.

SMB gain to date as at 2 May 2024 is 492 GT, 22 GT (4%) below the 2017-2022 average of 514 GT, and around 40 GT below the longterm average from DMI.

The first meaningful Melt event of the season has cpme and gone, a week or two later than average. It looks likely that only minimal melt is likely during the next week.

click gif to start, runs 5 times
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #22 on: May 18, 2024, 09:09:05 AM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
May 17 2024 In the last two weeks Spring retreated, with low melt and lowish precipitation.

SMB gain to date as at 17 May 2024 is 512 GT, 16 GT (3%) below the 2017-2022 average of 514 GT, and around 50 GT below the longterm average from DMI.

The first meaningful Melt event of the season in late April came and went, a week or two later than average. It looks likely that only minimal melt is likely during the next week.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #23 on: May 27, 2024, 02:58:27 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
May 26 2024 In the last 2 days signs of the longish period of low melt and lowish precipitation is switching to a more active scenario

SMB gain to date as at 26 May 2024 is 526 GT, 17 GT (3%) below the 2017-2022 average of 533 GT, and around 40 GT below the longterm average from DMI.

Melt though still below average increased in the last 2 days, and it looks as if daily melt will increase during the next week.
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #24 on: June 02, 2024, 09:02:56 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
June 2024 In the last week warmth & wet invades Greenland (mostly) coastal areas, more melt and higher precipitation - a more active scenario.

SMB gain to date as at 26 May 2024 is 549 GT, 1 GT (0%) below the 2017-2022 average of 550 GT, and around 25 GT below the longterm average from DMI.

Melt though still below average increased in the last week, and it looks as if daily melt may increase on one or two days during the next week.

click melt gif to start, runs 6 times.
« Last Edit: June 03, 2024, 01:26:51 AM by gerontocrat »
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #25 on: June 08, 2024, 08:54:56 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
7 June 2024 In the last 3 days warmth & wet invades Greenland Southern & coastal areas, more melt and higher precipitation - a more active scenario.

SMB gain to date as at 26 May 2024 is 560 GT, 6 GT (1%) above the 2017-2022 average of 550 GT, and around 25 GT below the longterm average from DMI.

Daily Melt has  increased to well above average in the last 3 days, and it looks as if daily melt may be above average on some days during the next week.

click melt gif to start, runs 6 times.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #26 on: June 11, 2024, 03:13:02 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
10 June 2024 In the last week warmth & wet invades Greenland Southern & coastal areas, more melt and higher precipitation - a more active scenario.

SMB gain to date as at 10 June 2024 is 568 GT, 13 GT (2%) above the 2017-2022 average of 555 GT, and around 15 GT below the longterm average from DMI.

Daily Melt has  increased to well above average in the last week, and it looks as if daily melt may be above average on some days, especially by the end of the week.

click melt gif to start, runs 6 times.
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #27 on: June 11, 2024, 04:59:20 PM »
Quote
SMB gain to date as at 26 May 2024 is 560 GT, 6 GT (1%) above the 2017-2022 average of 550 GT, and around 25 GT below the longterm average from DMI.

Average here is wrong? (it was 550 the previous update)?
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #28 on: June 17, 2024, 10:52:23 PM »
The 16th June was the first day this year we have seen a daily reduction in SMB, i.e. run-off from melt exceeded precipitation.

Melt continued to increase, thgough it looks like falling back to more average levels after today.
However, precipitation looks like being quite low during next week.

click melt gif to start, runs 6 times
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #29 on: June 19, 2024, 11:41:51 AM »
As at 18th June 2024

Daily Melt
Melt continued to increase, which may mean the high melt from about the 10th June is highest in the last 30 years. It still looks as if melt may moderate a bit after a day or two.

SMB
Melt has been so high in the last 3 days that run-off has exceeded precipitation, meaning cumulative SMB is reducing.
Nevertheless accumulated SMB for the 2023-24 year is at 575GT, 19GT (3%) above the 2017-2022 average of 556 GT, and very close to the the longterm average.
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #30 on: June 19, 2024, 11:53:05 AM »
NASA's JPL has issued GIS mass change to March 2024. In the month Mass Loss reduced by just 5GT, which given the SMB mass gain in the month of 75GT, implies a high rate of 70GT of mass loss from mostly calving and melting of ocean-terminating glaciers.
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #31 on: June 25, 2024, 08:49:48 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
24 June 2024 In the last 2 weeks warmth & wet invaded Greenland Southern & coastal areas, much melt and higher precipitation - a more active scenario.

SMB gain to date as at 24 June 2024 is 565 GT, 11 GT (2%) above the 2017-2022 average of 554 GT, and around 10 GT above the longterm average from DMI.
N.B. SMB is now reducing as run-off from melt exceeds precipitation. It looks as if that Greenland may be dryish over the next week or two, with also one or two days with rain on snow in the South. This could accelerate SMB loss.

Daily Melt has  increased to what may be record levels for the time of year, though it may have peaked. Note that in 2023 melt from now reached record levels for some time.

click melt gif to start, runs 6 times.
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #32 on: July 01, 2024, 09:06:00 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
30 June 2024

SMB gain to date is 561 GT, 18GT (2%) above the 2017-2022 average of 543 GT, and around 75 GT above the longterm average from DMI.

N.B. SMB should be now reducing as run-off from melt exceeds precipitation. In the last two days, despite very high melt, high precipitation has made a small increase in SMB.

Daily Melt has increased to what may be record levels for the time of year, but is now slightly below the record high melt in 2023 from now to late July.
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #33 on: July 01, 2024, 10:48:58 PM »
NASA's JPL has issued GIS mass change to April 2024. In the month Mass Loss increased by 29GT, which given the SMB mass gain in the month of 27GT, implies around 56GT mass loss from mostly calving and melting of ocean-terminating glaciers in the month..

click images to enlarge
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #34 on: July 08, 2024, 10:04:34 AM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
7 July 2024

SMB gain to date is 530 GT, 7GT (1%) above the 2017-2022 average of 523 GT, and very close to the longterm average from DMI.

N.B. SMB is now reducing as run-off from melt exceeds precipitation.

Daily Melt has increased to extreme levels for the time of year, but  below the record high melt in 2023 from now to late July.

click images to enlarge; and click gif to start, runs 6 times
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #35 on: July 16, 2024, 12:44:10 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
15 July 2024

SMB gain to date is 497 GT, 3GT (1%) above the 2017-2022 average of 494
 GT, and very close to the longterm average from DMI.

N.B. SMB is now reducing as run-off from melt exceeds precipitation.

Daily Melt has increased to extreme levels for the time of year, but  below the record high melt in 2023 from now to late July.

Despite the high melt, above average recipitation means daily SMB losses are at or a bit below average, in line with the climate models that forecast a warmer wetter Greenland.

click images to enlarge; and click gif to start, runs 6 times
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #36 on: July 19, 2024, 11:56:21 AM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
18 July 2024

SMB gain to date is 477GT, 4GT (1%) below the 2017-2022 average of 481GT, and very close to the longterm average from DMI.

N.B. SMB is now reducing as run-off from melt exceeds precipitation.

Daily Melt has increased to extreme levels for the time of year, but below the record high melt in 2023 from now to late July, until this day the 18th July, when melt covered 67% of the GIS.

Despite the high melt, above average recipitation means daily SMB losses have been mostly at or a bit below average, in line with the climate models that forecast a warmer wetter Greenland. The 17th & 18th July have been an exception, with daily SMB loss at 9GT on the 18th.

click images to enlarge; and click gif to start, runs 6 times
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #37 on: July 21, 2024, 06:40:43 AM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
20 July 2024

SMB gain to date is 458GT, 14GT (3%) below the 2017-2022 average of 472GT, and very close to the longterm average from DMI.

N.B. SMB is now reducing as run-off from melt exceeds precipitation.

For the last 3 days Daily Melt has increased to extreme and perhaps record levels for the time of year.

Despite the high melt, above average precipitation means daily SMB losses have been mostly at or a bit below average, in line with the climate models that forecast a warmer wetter Greenland. The 17th to 20th July have been an exception, with daily SMB loss at nearly 10GT on the 19th.

click images to enlarge
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #38 on: July 21, 2024, 09:10:14 AM »
  Spectacular data (NSIDC)

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #39 on: July 23, 2024, 09:06:51 PM »
  Spectacular data (NSIDC)
Looks like they changed their mind about that spike (see 1st image)

Of more importance is the huge difference between NSIDC Greenland Today data and the data from DMI.

This year Greenland Today has a maximum melt day of 30%, while for DMI (2nd image) it is 65%.

The cumulative data has the same problem (see 3rd image)

This year DMI has 2024 cumulative melt so far much less than in 2023. (4th image). DMI has cumulative melt slightly above 2023 (see 2nd image)

Last year I asked both DMI and the originator of Greenland Today data about this. DMI did not answer. The NSIDC just wrote that their model was OK. But either the models have totally different parameters and/or what they define as melt is different.

Me I am staying with DMI, mainly because DMI also publish Surface Mass Balance data, which I can compare with GIS mass changes to estimate mass loss from calving and melting of marine terminating glaciers.
« Last Edit: July 23, 2024, 09:19:03 PM by gerontocrat »
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #40 on: July 27, 2024, 11:36:32 AM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
26 July 2024

SMB gain to date is 427GT, 21GT (5%) below the 2017-2022 average of 448GT, and very close to the longterm average from DMI.

N.B. SMB is now reducing as run-off from melt exceeds precipitation.

Daily Melt remains at extreme levels for the time of year.

Until this day (26 July) daily SMB loss was mostly above average in July.

click images to enlarge
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #41 on: August 02, 2024, 11:01:16 AM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
1 August 2024

SMB gain to date is 419GT, 1GT (1%) above the 2017-2022 average of 418GT, and very close to the longterm average from DMI.

During July SMB losses and gains  were highly variable.

N.B. SMB should now be reducing as run-off from melt exceeds precipitation.

Daily Melt remains at extreme levels for the time of year.

click images to enlarge
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #42 on: August 09, 2024, 01:53:00 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
8 August 2024

SMB gain to date is377GT, 20GT (5%) below the 2017-2022 average of 397GT, and a bit below the longterm average from DMI.

During July SMB losses and gains  were highly variable.

N.B. SMB should, and is, be reducing as run-off from melt exceeds precipitation, but not for much longer.

Daily Melt remains at extreme levels for the time of year, continuing an impressive melt season.

click images to enlarge
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #43 on: August 16, 2024, 11:20:27 AM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
15 August 2024

SMB gain to date is 369GT, 17GT (4%) below the 2017-2022 average of 386GT, and very close to the longterm average from DMI.

N.B. SMB should be, and is, reducing as run-off from melt exceeds precipitation, but not for much longer.

Daily Melt has reduced somehwat in the last week, but remains at well above average levels for the time of year, continuing an impressive melt season. Cumulative melt may end above 2023's impressive melt.

I attach a gif of daily melt (last image). Click to start, runs 3 times

click images to enlarge
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #44 on: August 24, 2024, 05:40:29 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
23 August 2024

SMB gain to date is 358GT, 14GT (4%) below the 2017-2022 average of 372GT, and very close to the longterm average from DMI.

N.B. SMB should be, and is, reducing as run-off from melt exceeds precipitation, but should change to SMB gains over the next few daya.

Daily Melt has reduced somewhat in the last week down to almost average levels, continuing an impressive melt season, with cumulative melt already above 2023's impressive melt. GFS temperature data suggests that some days in the next week melt could pick up somewhat.

N.B. This is a completely different result from NSIDC's Greenland Today analysis. Either they are measuring melt on a completely different basis or one of the algorithms is producing junk. (see next post)

click images to enlarge
« Last Edit: August 24, 2024, 05:47:45 PM by gerontocrat »
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gerontocrat

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #45 on: August 24, 2024, 05:50:12 PM »
GIS Melt - extreme variation between DMI and NSIDC Results

N.B. The DMI melt data produces a completely different result from NSIDC's Greenland Today analysis. Either they are measuring melt on a completely different basis or one of the algorithms is producing junk.

& here are the graphs to show it

ps: I have sent an email to DMI and NSIDC. If it is the same as last year it will be ignored (DMI) or poo-hooed (NSIDC).
« Last Edit: August 25, 2024, 08:02:12 AM by gerontocrat »
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #46 on: August 24, 2024, 08:38:53 PM »
I flew over Greenland a couple of days ago around the Arctic Circle and it was clear blue sky along the coast definitely looked likely to be melting.

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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #47 on: September 01, 2024, 05:31:53 PM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
31 August 2024

The DMI year for SMB has now finished. SMB gain for the year is 368GT, 13GT (3%) below the 2017-2022 average of 381GT, and very close to the longterm average from DMI. The SMB-ACC map shows where SMB increased and where it decreased.

DMI uses the calendar year for melt data. Daily Melt has reduced somewhat in the last week down to average levels, continuing an impressive melt season, with cumulative melt already much above 2023's impressive melt. GFS temperature data suggests that on one or two days next week melt could pick up a bit.

Summary for SMB year 2023-2024
Climate scientists tell us that precipitation is increasing, though with more rain on snow events.
They also tell us that melt is increasing, which the melt graph also shows.

This year has that despite very high melt, the SMB gain is close to the long-term average, which arithmetic says must mean precipitation was above the average.

In the longer-term AGW means a warmer, wetter Greenland, and climate science forecasts that due to higher melt and increased run-off the increase in precipitation is not enough to prevent annual SMB gains gradually decreasing in the years to come. (see graph next post)

The SMB gain of 368 GT plus GIS annual mass loss of around 250 GT tells us annual mass loss from run-off plus calving plus melting of marine-terminating glaciers and basal melt is probaly at least 600 GT per annum.

click images to enlarge
click gif to start, runs 5 times, (each run around 40 seconds)
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #48 on: September 01, 2024, 05:35:02 PM »
DMI SMB 2023-24

This paper is all about trends in annual SMB gains
https://tc.copernicus.org/articles/16/315/2022/tc-16-315-2022.html
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Re: Greenland 2023-24 SMB, melting and GRACE mass
« Reply #49 on: October 03, 2024, 09:45:25 AM »
This thread is about the Surface Mass Balance change (i.e. snowfall) from 1 Sept 2023 to 31 Aug 2024, and Surface Melt April to October 2024,
plus DMI and JPL GIS Mass Loss data from GRACE /GRACE-FO data (whenever it is updated).

_________________________________________
2024 Melt Data

The melting season is over apart from occasional minor melt on odd days.

The contrast between DMI melt data and NSIDC's Greenland Today data is extreme. DMI shows accumulated melt measured in Km2 at 65 million km2, NSIDC Greenland Today at 18 million lm2.

In other words the DMI data shows that 2024 melt was extremely high, Greenland Today that melt was well below the 2010's average.

I wrote to NSIDC and DMI about it. They did look at it and both are sticking to their algorithms.
So you make a choice on which you go with.


click images to enlarge
"Para a Causa do Povo a Luta Continua!"
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