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Author Topic: Greenland 2019-20 SMB (Snowfall & Melting) Year  (Read 56190 times)

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #200 on: August 20, 2020, 09:46:02 AM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 19 Aug 2020.

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

Precipitation low,

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

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

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

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crandles

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #201 on: August 20, 2020, 07:12:55 PM »
Return to rapid ice loss in Greenland and record loss in 2019 detected by the GRACE-FO satellites

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



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


BBC is saying "breaking the previous record by 15%". 532 compared to 2012's 437 is over 21%. that 437 is a 2 year period.
« Last Edit: August 20, 2020, 07:23:41 PM by crandles »

sidd

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #202 on: August 20, 2020, 11:08:00 PM »
Thats a good paper, i am glad to see they resolved the discrepancy noted in an earlier paper this year from Velicogna et al (ref 14 in the paper citd above ...)

sidd

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #203 on: August 21, 2020, 02:00:19 PM »
Thats a good paper, i am glad to see they resolved the discrepancy noted in an earlier paper this year from Velicogna et al (ref 14 in the paper citd above ...)

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

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

Data as at 20 Aug 2020.

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

Precipitation quite low,

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

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

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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #204 on: August 21, 2020, 09:56:08 PM »
Thats a good paper, i am glad to see they resolved the discrepancy noted in an earlier paper this year from Velicogna et al (ref 14 in the paper citd above ...)

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

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

ps: High GIS mass loss in 2019? - You saw it first on this thread
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #205 on: August 22, 2020, 02:03:03 PM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 21 Aug 2020.

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

Precipitation quite low,

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

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

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"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #206 on: August 23, 2020, 03:11:07 PM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 22 Aug 2020.

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

Precipitation low,

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

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

_______________________________________
click each image for full-size.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #207 on: August 24, 2020, 11:47:54 AM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 23 Aug 2020.

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

Precipitation up a bit.

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

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

_______________________________________
click each image for full-size.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #208 on: August 25, 2020, 03:58:11 PM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

Data as at 24 Aug 2020.

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

Precipitation average?.

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

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

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

________________________________________
Note that the DMI starts a new year on 1st September for SMB data, despite that melt certainly can be significant at least in the first half of the month. So I will keep the thread open and extend the graphs until...?
AGW is such a nuisance.
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #209 on: August 26, 2020, 02:16:01 PM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   

Data as at 25 Aug 2020.

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

Precipitation above average?.

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

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

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

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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #210 on: August 27, 2020, 12:54:34 PM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   

Data as at 26 Aug 2020.

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

Precipitation above average?.

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

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

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

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

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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #211 on: August 28, 2020, 11:51:47 AM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

End of the melting season?   

Data as at 27 Aug 2020.

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

Precipitation above average?.

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

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

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

GFS reliability seems to be getting somewhat less - change of season wobbles?
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #212 on: August 29, 2020, 11:33:21 AM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

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

Data as at 28 Aug 2020.

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

Precipitation above average?.

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

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

GFS reliability seems to be getting somewhat less - change of season wobbles?
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #213 on: August 30, 2020, 01:33:31 PM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

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

Data as at 29 Aug 2020.

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

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

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

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

SMB gains - maybe some large - in prospect.

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

Why? Precipitation. This year the blocking high over Greenalnd was insufficient to prevent weather systems dumping precipitation on Greenland. A very average result for the year end concealing a lot of high energy weather?
_________________________________________________________________
(It seems that in 2012 the melt season was characterised by the combination of high melt and very low precipitation, which led to the record low SMB gain for the year. Spectacular Greenland blocking high?).
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #214 on: August 31, 2020, 12:08:28 PM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

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

Data as at 30 Aug 2020.

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

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

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

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

SMB gains - maybe some large - in prospect.

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

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #215 on: September 01, 2020, 02:31:33 PM »
Data from...
http://polarportal.dk/en/greenland/surface-conditions/
http://ensemblesrt3.dmi.dk/data/prudence/temp/PLA/PP_GSMB/

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

Data as at 31 Aug 2020.

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

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

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

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

SMB gains - maybe some large - in prospect.

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

Although it is the end of the year as far as DMI is concenrned, I will keep the Melt and SMB graphs from my spreadsheet open for a bit longer.
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oren

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #216 on: September 02, 2020, 06:57:46 AM »
It's been a weird August with lots of precipitation and the accumulated SMB line refusing to drop. However I wonder if, while more melt and more precipitation in tandem equal a stable SMB number, if they also equal a stable ice mass loss. Higher surface melt could also mean faster discharge and faster marine melting.

gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #217 on: September 02, 2020, 01:52:31 PM »
It's been a weird August with lots of precipitation and the accumulated SMB line refusing to drop. However I wonder if, while more melt and more precipitation in tandem equal a stable SMB number, if they also equal a stable ice mass loss. Higher surface melt could also mean faster discharge and faster marine melting.
Add to that a steaming Baffin Sea.

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

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


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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #218 on: September 03, 2020, 08:53:29 PM »
GIS - SMB + Total Mass Loss.

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

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

Looks much better if you click the image for full size.
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #219 on: September 14, 2020, 11:03:39 PM »
And GFZ have just updated their GRACE-FO data to July - so here are the graphs .
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #220 on: September 20, 2020, 11:03:15 PM »
NSIDC Greenland Today have produced  a nearly end-of-season report

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






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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #221 on: September 24, 2020, 01:54:22 PM »
2020 SMB + Melt from June to Sept 22

A LARGE GIF


click to play, or you can download it by clicking on the filename below the image and then run it offline on an app of your choice.
« Last Edit: September 24, 2020, 02:05:53 PM by gerontocrat »
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #222 on: November 01, 2020, 07:47:35 PM »
My last posts on this thread until we see the DMI and NSIDC annual reports.

We have the GRACE-FO data on changes in the Greenland Ice Sheet mass to August 2020, Graphs and the basin map attached. Not as impressive as 2019.

From 2002 to August 2020 the GIS has lost 4,250 GigaTons of ice, increasing sea levels by just under 12 mm.
In the DMI Greenland year Sept 19 to Aug 20 GIS ice mass loss was 295GT.

As usual, the most rapid mass loss occurs in the South West and basin 306 in particular.

ps: remember there is a data gap between GRACE & GRACE-FO in most of 2017-2018 that the graph fills in on autopilot.
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gerontocrat

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #223 on: November 01, 2020, 08:02:41 PM »
And here is the second post which combines SMD data from DMI with GIS mass change from GRACE-FO,

The graph starts at October 2018 when monthly GIS data resumed (and is always one or two months later than arriving than the daily DMI data).

Of interest is that the data suggests that in August 2020 nearly all GIS mass loss was from surface melt, i.e. reduced SMB. This implies almost zero calving and glacial melt, which I find hard to believe. But that's what the data says.

The GRACE-FO data is a physical measure, the DMI SMB data is from a model using very limited data from a small number of physical measurements.
« Last Edit: November 01, 2020, 08:39:06 PM by gerontocrat »
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nukefix

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Re: Greenland 2019-20 SMB (Snowfall & Melting) Year
« Reply #224 on: November 04, 2020, 07:23:45 AM »
Of interest is that the data suggests that in August 2020 nearly all GIS mass loss was from surface melt, i.e. reduced SMB. This implies almost zero calving and glacial melt, which I find hard to believe. But that's what the data says.

The GRACE-FO data is a physical measure, the DMI SMB data is from a model using very limited data from a small number of physical measurements.
It looks like the calving data had not arrived when that graph was made - look at the cumulative lines.

GRACE-FO is a complicated measurement with a resolution of around 300km so there is some signal leaking in from Canadian arctic ice caps for example.  SMB-models are quite sophisticated and high resolution these days with combination of satellite observations + forcing at the boundaries with the best available physical weather model reanalysis data (ERA5) that is of very high quality these days I'd say. I don't know if the DMI model is at the same level as the best ones like RACMO and others.