Arctic Sea Ice : Forum

Cryosphere => Greenland and Arctic Circle => Topic started by: gerontocrat on January 13, 2019, 08:37:02 AM

Title: Greenland 2019 Melt Season
Post by: gerontocrat on January 13, 2019, 08:37:02 AM
https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

2019 MELT SEASON - 2018-2019 SMB SEASON As at 12 Jan 2019

Some dry days and wet days so far this year.

And for the next 5 to 10 days it looks like,
- no melt,
- below average precipitation,
- SMB balance year to date a bit more below average.


_____________________________________________________________
SMB = Surface Mass Balance, which excludes mass loss from calving that on average is greater than SMB gain in the year. i.e. usually Greenland loses mass every year.

GRACE follow-on data - where are you?
_____________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on January 20, 2019, 06:25:01 PM
https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

2019 MELT SEASON - 2018-2019 SMB SEASON As at 19 Jan 2019

Some dry days and wet days so far this year.

And for the next 5 to 10 days it looks like,
- no melt,
- Some dryish days and some wettish days,
- SMB balance year to date stays below average.

In other words - no change


_____________________________________________________________
SMB = Surface Mass Balance, which excludes mass loss from calving that on average is greater than SMB gain in the year. i.e. usually Greenland loses mass every year.

GRACE follow-on data - where are you?
_____________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: lurkalot on January 22, 2019, 10:28:50 AM
Is this news?
https://www.theguardian.com/world/2019/jan/21/greenland-ice-melting-faster-than-scientists-previously-thought-study
Title: Re: Greenland 2019 Melt Season
Post by: oren on January 22, 2019, 01:05:42 PM
I haven't read the whole paper yet, buy as the study uses GRACE data up to 2016, I would guess the only news is the locality of mass loss. If the Southwest is producing more melt, some other area of the ice sheet is producing less, given that GRACE has measured the total mass of the ice sheet with reasonable accuracy.
The big news will come once the new GRACE data becomes operational. Then we will know if ice mass loss has slowed or even stopped in 2017-18, as indicated by a better surface mass balance and by the seeming slowdown in Jakobshavn calving.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on January 24, 2019, 07:24:10 AM
https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

2019 MELT SEASON - 2018-2019 SMB SEASON As at 19 Jan 2019

Some dry days and wet days so far this year.

And for the rest of he month it looks like,
- no melt,
- Some dryish days and some wettish days but overall below average,
- SMB balance year to date further below average.

In other words - not a lot of change


_____________________________________________________________
SMB = Surface Mass Balance, which excludes mass loss from calving that on average is greater than SMB gain in the year. i.e. usually Greenland loses mass every year.

GRACE follow-on data - where are you?
_____________________________________________________________
Title: Re: Greenland 2019 Melt Season & Surface Mass Balance (SMB) 2018-19
Post by: gerontocrat on January 30, 2019, 12:39:54 PM
https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

2019 MELT SEASON - 2018-2019 SMB SEASON As at 29 Jan 2019

In the last week,
- no melt,
- Some dryish days and some wettish days but overall below average,
- SMB balance year to date further below average.

And for next 10 days it looks like,
- no melt,
- Some dryish days and some wettish days but overall below average,
- SMB balance year to date further below average.

In other words - not a lot of change


_____________________________________________________________
SMB = Surface Mass Balance, which excludes mass loss from calving that on average is greater than SMB gain in the year. i.e. usually Greenland loses mass every year.

GRACE follow-on data - where are you? Has Trump's shutdown delayed things?
_____________________________________________________________
Title: Re: Greenland 2019 Melt Season & Surface Mass Balance (SMB) 2018-19
Post by: gerontocrat on February 02, 2019, 09:35:33 AM
https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

2019 MELT SEASON - 2018-2019 SMB SEASON As at 1 Feb 2019

In the last week,
- no melt,
- Some dry days and some wettish days but overall below average,
- SMB balance year to date further below average.

And for next 10 days it looks like,
- no melt,
- Mostly dryish days and some wettish days but overall well below average,
- SMB balance year to date further below average.

In other words - perhaps a significant change due to lack of precipitation. (Most of Canada looking pretty dry as well)


_____________________________________________________________
SMB = Surface Mass Balance, which excludes mass loss from calving that on average is greater than SMB gain in the year. i.e. usually Greenland loses mass every year.

GRACE follow-on data - where are you? Has Trump's shutdown delayed things?
_____________________________________________________________
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on February 04, 2019, 11:19:16 PM
Denmark's Meteorological Institute have gone and decided to do a website makeover. Perhaps they have got a new IT director who has to show he has done something, anything, to justify his existence.

So asking for this;- https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

gets you this:-

The page does not exist
Sorry, we can't find the page you're looking for. This may be because beta.dmi.dk is under construction.

Try one of these links instead:
front page
switch, Contact
About the weather
How to get the most out of the weather on the new website


DMI temp north of 80 link still works, as does the SST site, though I expect this will be screwed up as well.
Title: Re: Greenland 2019 Melt Season & Surface Mass Balance (SMB) 2018-19
Post by: gerontocrat on February 06, 2019, 10:08:29 AM
The Danes haved moved the information to their polar portal at:-
http://polarportal.dk/en/greenland/surface-conditions/

They've also changed the graphics

2019 MELT SEASON - 2018-2019 SMB SEASON As at 5 Feb 2019

In the last week,
- no melt (apart from some sublimation),
- Some dry days and some wettish days but overall below average,
- SMB balance year to date further below average. Image shows where precipitation is and is not happening.

And for next 10 days it looks like,
- no melt,
- Mostly dryish days and some wettish days but overall below average,
- SMB balance year to date further below average.

In other words - perhaps a continuing change due to lack of precipitation. (Most of Canada looking pretty dry as well). GFS image attached

They've also added an albedo image

_____________________________________________________________
SMB = Surface Mass Balance, which excludes mass loss from calving that on average is greater than SMB gain in the year. i.e. usually Greenland loses mass every year.

GRACE follow-on data - where are you?
_____________________________________________________________
Title: Re: Greenland 2019 Melt Season & Surface Mass Balance (SMB) 2018-19
Post by: litesong on February 07, 2019, 05:08:46 AM
And for next 10 days it looks like,
- no melt,
- Mostly dryish days and some wettish days but overall below average,
- SMB balance year to date further below average.

In other words - perhaps a continuing change due to lack of precipitation. (Most of Canada looking pretty dry as well).
Meanwhile:
Our Pacific Northwest U.S., after record January 2019 warm temperature, now has Arctic & far northern Canadian cold pushing through the BC's Fraser Valley, spreading cold, mixing with Pacific Ocean moisture & presenting a foot of snow, east of Salish Sea(Puget Sound). Our local morning temps are 11degF. Now, predictions are for more snow. Our increasing cold, coming from Canada & the Arctic, & Pacific moisture, NOT reaching Canada, agrees with your assessment for northern Canada & the Arctic.
Title: Re: Greenland 2019 Melt Season & SMB 2018-19
Post by: gerontocrat on February 09, 2019, 10:23:09 AM
http://polarportal.dk/en/greenland/surface-conditions/

2019 MELT SEASON - 2018-2019 SMB SEASON As at 8 Feb 2019

In the last few days,
- no melt (apart from some sublimation),
- Some dry days and some wettish days but overall well below average,
- SMB balance year to date further below average. 2nd image shows where precipitation is and is not happening.

And for next 10 days it looks like,
- no melt,
- Mostly dryish days and some wettish days but overall below average,
- SMB balance year to date further below average. At already well over 50 GT or 25% below that average, becoming significant.

In other words - perhaps a continuing change due to lack of precipitation. (Most of Central and Northern Canada looking pretty dry as well). GFS image attached.
_____________________________________________________________
SMB = Surface Mass Balance, which excludes mass loss from calving that on average is greater than SMB gain in the year. i.e. usually Greenland loses mass every year.

GRACE follow-on data - where are you?
_____________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on February 12, 2019, 04:20:44 PM
Dropping towards the bottom on SMB
Title: Re: Greenland 2019 Melt Season & SMB 2018-19
Post by: gerontocrat on February 15, 2019, 01:49:22 PM
http://polarportal.dk/en/greenland/surface-conditions/

2019 MELT SEASON - 2018-2019 SMB SEASON As at 14 Feb 2019

In the last few days,
- no melt (apart from some sublimation),
- Some dry days and some wettish days but overall well below average,
- SMB balance year to date further below average.

And for next 10 days it looks like,
- no melt,
- Mostly dryish days and some wettish days but overall below average,
- SMB balance year to date further below average. At already well over 50 GT becoming significant. This is in major contrast with Snow Water Equivalent (i.e. Mass) in North America and Eurasia both running at well over +1 SD above average.

In other words - perhaps a continuing change to further below average SMB due to lack of precipitation.  GFS image attached.
_____________________________________________________________
SMB = Surface Mass Balance, which excludes mass loss from calving that on average is greater than SMB gain in the year. i.e. usually Greenland loses mass every year.

GRACE follow-on data - where are you? This is what Germany said late last year___
GRACE Follow-On: Mission Status and Schedule
Mission operations are currently nominal, with continuous collection of K-band ranging
observations. The mission is currently in IOC, with a planned transition into Phase-E
(Science Phase) on Jan-28, 2019. After a Validation & Verification phase (up to 120-
days), Level-1 Science Data deliveries will commence in Spring 2019
_____________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on February 18, 2019, 05:47:37 PM
Line continues to trend towards the lower edge of the 30 year band:
Title: Re: Greenland 2019 Melt Season
Post by: oren on February 19, 2019, 04:11:37 AM
I must say it's becoming a bit disturbing. A lot of it is random variation but recently all coins fell on the same side. After a couple of good years, we may be sliding back towards the abyss.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on February 20, 2019, 01:19:03 PM
I must say it's becoming a bit disturbing. A lot of it is random variation but recently all coins fell on the same side. After a couple of good years, we may be sliding back towards the abyss.
Whereupon, it seems that maybe it is a case of "all-change".

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

In the last 2 days, precipitation has been above average. It looks very much as if the southern and eastern coasts of Greenland are going to have a lot of precipitation over at least the next week to 10 days. Is there a significant change in Arctic weather underway ?

Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on February 23, 2019, 11:51:41 AM


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

In the last few days, precipitation has been well above average. However, the signal for above average precipitation in the next week or so seems to have weakened.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on March 01, 2019, 01:22:33 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at Feb 28 2019

Note the strong sublimation on the West Coast on the 28th.

In the last few days, precipitation has been well above average and below average. However, the signal for precipitation in the next week or so seems to have weakened (as has that for North America as a whole).
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on March 06, 2019, 12:09:09 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 5 March 2019


In the last week or so , precipitation was well above average for a few days and in the last 2 days well below average.
Accumulated SMB in the year to date is well over 50 GT (circa 15 to 20%) below average.

The forecast for precipitation in the next week or so is for very low precipitation. The contrast with North America is great.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on March 12, 2019, 01:11:04 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 11 March 2019

In the last 5 days or so, precipitation was mostly well below average.
Accumulated SMB in the year to date is around 75 GT (circa 15 to 20%) below average.

The forecast for precipitation in the next week or so is for very low precipitation followed by in a few days by above average precipitation in the S.E. quadrant.

The contrast with North America is currently very great. However, there are signs for the remainder  of March of increased warmth meaning less snow and more rain..
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on March 18, 2019, 11:28:48 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 17 March 2019

In the last 5 days or so, precipitation was mostly well below average.
Accumulated SMB in the year to date is around 75 GT or more (circa 15 to 20%) below average.

However, it looks likely that precipitation could be somewhat above average over the next few days. This includes at least one cyclonic event from the S.E. identified in the recent paper about the significance and increasing frequency of summer and winter rainfall events.

The contrast with North America continues - now N. America gets a bit dryer as Greenland gets a bit wetter.
___________________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on March 23, 2019, 10:37:02 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 22 March 2019

In the last 5 days or so, precipitation was mostly a bit above average.
Accumulated SMB in the year to date is still around 75 GT or more (circa 15%) below average.

It looks likely that precipitation could be somewhat above average over the next few days and concentrated in the south. This includes at least one cyclonic event being rain from much farther south in the Atlantic which GFS assumes to turn to snow when hitting the Greenland coast, even though GFS shows at or above freezing temperatures on that southern coastal fringe. Increasing frequency of summer and winter rainfall events ?

The contrast with North America continues - now N. America gets a bit dryer as Greenland gets a bit wetter.
___________________________________________________________________
ps: Latest on GRACE Follow-on I can find is from https://climate.nasa.gov/vital-signs/ice-sheets/

Quote
Please note that the most recent data are from June 2017, when the GRACE mission concluded science operations. Users can expect new data from GRACE’s successor mission, GRACE Follow-On, in the summer of 2019.​
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on March 28, 2019, 03:19:13 PM
SMB continues to be at the lower end of the range...
Title: Re: Greenland 2019 Melt Season
Post by: Darvince on March 31, 2019, 07:49:20 PM
Looks like possibly the first melt event of the season coming in a few days? It brings with it rain, and snow for higher elevations.

(https://i.imgur.com/c25zwrO.png)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 01, 2019, 12:03:13 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 31 March 2019

In the last 10 days or so, precipitation was more above average than below.
Accumulated SMB in the year to date is still around 75 GT (circa 15%) below average.

It looks likely that precipitation could be somewhat above average over the next few days and concentrated in the south. This includes at least one cyclonic event on this Tuesday as noted by Darvince (see post above) being rain from much farther south in the Atlantic which GFS assumes to turn to freezing rain and snow when hitting the Greenland SW coast, even though GFS shows at or above freezing temperatures on that southwest coastal fringe.
Will this show as melting on the DMI map for the day?
Increasing frequency of summer and winter rainfall events ?
___________________________________________________________________
ps: Latest on GRACE Follow-on I can find is from https://climate.nasa.gov/vital-signs/ice-sheets/

Quote
Please note that the most recent data are from June 2017, when the GRACE mission concluded science operations. Users can expect new data from GRACE’s successor mission, GRACE Follow-On, in the summer of 2019.​

pps: NSIDC's "Greenland Today" should be waking up this month.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 03, 2019, 10:25:48 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 31 March 2019

The cyclonic event on Tuesday  2 April as noted by Darvince (see post above) did happen. Parts of the SW coast and inland were above freezing. (first image). Rain from much farther south in the Atlantic was partly rain, partly freezing rain and partly snow. The rain is shown as penetrating some way inland (see image 2).

Did this show as melting on the DMI SMB map for the day? NO
___________________________________________________________________
ps: Latest on GRACE Follow-on can be found at https://media.gfz-potsdam.de/gfz/sec12/pdf/GRACE_FO_SDS_newsletter_No2.pdf

Data in May June?


pps: NSIDC's "Greenland Today" should be waking up this month.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Darvince on April 05, 2019, 04:19:06 AM
There does seem to have been more than zero melt extent as calculated by DMI's melting algorithm rather than surface mass balance algorithm, seen here (look very closely at the southwest Greenland coast):

(https://i.imgur.com/8vPslIO.png) (https://i.imgur.com/8vPslIO.png)

I am guessing that as usual for the earliest above-freezing temperatures, it shows as positive mass balance because any rain refroze in the ice.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 06, 2019, 09:22:52 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 5 April 2019

In the last week or so, precipitation was more above average than below.
Accumulated SMB in the year to date is still around 75 GT (circa 15%) below average.

On some days warmth has entered Baffin Bay with resulting melt (probably sublimation) along the SW coast (see todayssmb map). GFS predicts several days of fairly strong +ve temperature anomalies in Baffin Bay in the next 10 days. More sublimation, or even a melt event?

It looks likely that precipitation could be somewhat below average over the next 10 days apart from a small area of high precipitation on the SE coast.  This precipitation is predicted to come from the SE or East as a mixture of rain and snow.
___________________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: uniquorn on April 10, 2019, 10:48:50 PM
Maybe it happens occasionally, but I don't remember seeing 125km winds over Greenland.
https://tinyurl.com/y2l287lk
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 14, 2019, 10:27:27 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 13 April 2019

The 13th April was a genuine melting event (see first image attached). Only a little one but a melt event nevertheless.

In the last week or so, precipitation was more above average than below.
Accumulated SMB in the year to date is still well below average but increasing strongly, especially on the coastal region of the SE.

It looks likely that precipitation could be very much average over the next 10 days especially  on the SE coast.  Much of this precipitation is predicted to come from the SE or East as a mixture of rain and snow.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 16, 2019, 11:05:54 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 15 April 2019

The 13th April melting event has continued to 15th April, only a little one but a bit stronger on the 15th. It may well be the last such event for at least 10 days
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 17, 2019, 11:07:05 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 16 April 2019

I was wrong - again. The melting event has persisted into the 16th April.
Quote
The 13th April melting event has continued to 15th April, only a little one but a bit stronger on the 15th. It may well be the last such event for at least 10 days
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 21, 2019, 06:40:32 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 20 April 2019

This melting event has persisted unto the 20th April.
Quote
The 13th April melting event has continued to 15th April, only a little one but a bit stronger on the 15th. It may well be the last such event for at least 10 days
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 23, 2019, 10:24:46 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 22 April 2019

Melting
The 13th April melting event has continued until the 22 April. Only a little one but a melt event nevertheless and early.. It looks as if the South West coast will be getting bursts of warmth on most days from 27th April onwards (per GFS). This is backed up by the weather forecast for Nuuk predicting daytime maxima of around +5 to +7 next week and beyond. This could produce a stronger and persistent melt event.

precipitation
In the last 2 weeks or so, precipitation was much above average.
Accumulated SMB in the year to date is still below average but increased strongly, especially on the coastal region of the SE.

It looks likely that precipitation could be very much average over the next 10 days especially  on the SE coast.  Much of this precipitation is predicted to come from the SE or East as a mixture of rain and snow.
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on April 23, 2019, 07:42:48 PM
This is the weather forecast for Narssasuaq, close to the southern tip of Greenland:
Looks like really melting weather there.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 25, 2019, 08:06:27 AM
And GFS saying that Greenland (and Baffin Bay) is going to have a sustained and substantial melting event starting sometime this Sunday and continuing until ....?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 26, 2019, 12:09:54 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 25 April 2019

Melting
The 13th April melting event has never totally stopped, just reduced. Only a little one but a melt event nevertheless and early and persistent.. It looks as if it is already a tad stronger on the 25th. It also looks as if the Southern Greenland coast will be getting bursts of warmth to above freezing on most days from 27th April onwards and very strongly in the entirety of Baffin Bay next Monday. (per GFS).

precipitation
In the last 2 weeks or so, precipitation was much above average. Accumulated SMB in the year to date is still below average but increased strongly, especially on the coastal region of the SE. 

It looks likely that precipitation could be very much average over the next 10 days especially  on the SE coast.  Much of this precipitation is predicted to come from the SE or East as a mixture of rain and snow.

It is just possible that melt could exceed precipitation for a day or two in the period Sunday to Tuesday. Now that would be early
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on April 26, 2019, 03:21:04 PM
Updated weather forecast for Narssarsuaq - still heading towards massive melting.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on April 26, 2019, 03:43:25 PM
Another forecast (https://binged.it/2vnkSXY) for Narsarsuaq is a little less hot (only up to 11º).  Here are the temp norms and extremes for this time of year for this south Greenland village.  Rain is definitely in the forecast!
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 27, 2019, 09:35:41 PM
melt increases a little bit

For those who might not know, NSIDC has a Greenland webpage.
http://nsidc.org/greenland-today/

I think they use a somewhat different model that produces similar but not the same results as DMI
Also the maps are much lower resolution.

They also do not operate the site in winter as it really just looks at melt apart from the end of Greenland Year (Sept to August) analysis.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 28, 2019, 01:28:09 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 27 April 2019

Melting
The 13th April melting event has never totally stopped, just reduced. Only a little one but a melt event nevertheless and early and persistent.. The melt is already stronger by the 27th. As yet the melt does not show on the West coast even though GFS showed above zero temperatures on that coast on Saturday. It also looks as if these bursts of warmth to above freezing on the Southern Greenland coast will be considerable stronger today (the 28th April), and in the entirety of Baffin Bay next Monday.

Indeed, the whole of Greenland looks like having very much above temperatures for a good few days.

I will be surprised if the melt map for today the 28th does not show melting on the West coast and also spreading further north on both coasts.

precipitation
In the last 2 weeks or so, precipitation was much above average. Accumulated SMB in the year to date is still below average but increased strongly, especially on the coastal region of the SE. 

GFS is indicating that over the next 10 days it looks like that precipitation could be very much below average over the next 10 days except for the extreme SE coast. In that small area  perhaps much of this very high precipitation could be a mixture of rain and snow.

It is just possible that melt could exceed precipitation for a day or two in Monday or Tuesday. Now that would be early
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on April 28, 2019, 04:54:57 PM
nice outlook for inhabitants:

Temps of:
>15C for several consecutive days, starting from tomorrow not that common in April AFAIK
Title: Re: Greenland 2019 Melt Season
Post by: Niall Dollard on April 28, 2019, 06:20:27 PM
The east of Greenland has been warm of late (many stations up to 8 C) and now it will be the turn of the west.

There are quite a few different forecasts out there. All of them forecasting warmth but bit of a disagreement as to how warm it will get.

I tend to use the yr.no forecast for these lattitudes. 

Here is their forecast for Sisimiut (Qeqqata) - roughly in yellow area where Magnamentis has highlighted.

https://www.yr.no/place/Greenland/Qeqqata/Sisimiut/long.html
Title: Re: Greenland 2019 Melt Season
Post by: BenB on April 29, 2019, 11:58:06 AM
The (relatively) warm weather in Greenland is reflected in a further spike in the melt extent:

(https://nsidc.org/greenland-today/images/greenland_daily_melt_plot.png)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 29, 2019, 12:48:24 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 28 April 2019

Melt
And here is 28 April by DMI.  Definitely a chance of  daily SMB change going -ve over the next day or two. All depends on precipitation in the SE :- amount and rain / snow mixture.
Title: Re: Greenland 2019 Melt Season
Post by: Niall Dollard on April 30, 2019, 12:13:09 AM
nice outlook for inhabitants:

Temps of:
>15C for several consecutive days, starting from tomorrow not that common in April AFAIK

Kangerlussuaq managed a max of 15.3 C today. Here is a picture of the weather station from Google Street taken in July 2016 (yes they even got to Greenland).

It's a dry spot, well inland. Could be almost mistaken for Arizona.  :)

https://goo.gl/maps/PGT8j2TiHdCxqjcF8

Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on April 30, 2019, 12:08:10 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 29 April 2019

Melt
And here is 29 April by DMI.  Precipitation > Melt.
Looking as if some level of melt going to persist for some time.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on April 30, 2019, 04:42:15 PM
The (relatively) warm weather in Greenland is reflected in a further spike in the melt extent:
...
I was curious to compare Ben's chart with 2012 - the year of the big melt.  NSIDC gives the comparison with their interactive map (https://nsidc.org/greenland-today/greenland-surface-melt-extent-interactive-chart/) (with 2012 and 2019 pre-selected!)  I selected the years with notable early melt to put 2019 into perspective (below).  Note that the 'grey zones' hardly register until May.
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on April 30, 2019, 08:58:11 PM
...so until now the melt area 2019 in Greenland is nothing to write home about.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 01, 2019, 01:39:24 AM
2019 has more early melt than most years, and is among the half-dozen years with early melt.  A couple years, however, had much more significant melt events before May.  So perk up your ears, but don't write home yet!  :)
Title: Re: Greenland 2019 Melt Season
Post by: BenB on May 01, 2019, 09:17:30 AM
Great comparison, Tor. It will be interesting to see what happens over the coming days, with Greenland temperatures forecast to remain high for some time.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 01, 2019, 09:55:14 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 30 April 2019

Melt
And here is 30 April by DMI.
Melt increasing.

Melt has been early, persistent and well above average for the time of year. All part of  climate change, and a significant change in albedo for a significant area of the Greenland fringe.
AGW is not always about drama.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 01, 2019, 10:46:48 AM
The south-west coast of Greenland. Natural Colours Band.

27.04. vs 29.04. (both ~16:00 UTC)

(The one with less snow cover is the 27th)
Title: Re: Greenland 2019 Melt Season
Post by: Niall Dollard on May 01, 2019, 11:38:29 PM
The south-west coast of Greenland. Natural Colours Band.

(The one with less snow cover is the 27th)

I imagine you mean the other way around. (29th less cover).  :)
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 02, 2019, 05:44:20 AM
The south-west coast of Greenland. Natural Colours Band.

27.04. vs 29.04. (both ~16:00 UTC)

(The one with less snow cover is the 29th)

Edit! Thanks, Niall for the correction.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 02, 2019, 05:45:04 AM
I imagine you mean the other way around. (29th less cover).  :)

Indeed. Sorry for the confusion.
Title: Re: Greenland 2019 Melt Season
Post by: Darvince on May 02, 2019, 01:11:43 PM
DMI should declare 'open season' on the melting season tomorrow as their criteria for 5% or greater melt extent for three consecutive days is all but assured to be met.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 02, 2019, 02:50:55 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 1 May 2019

DMI should declare 'open season' on the melting season tomorrow as their criteria for 5% or greater melt extent for three consecutive days is all but assured to be met.

I think tomorrow came yesterday (May 1). Looking at weather.com (as https://climatereanalyzer.org/ is out of action) it looks like the West Coast will stay warm enough to keep the melt going at well above 5% at least until Sunday.

Title: Re: Greenland 2019 Melt Season
Post by: jai mitchell on May 02, 2019, 08:57:34 PM
Can this temp anomaly on west Greenland be correct?

Temps > 12C

https://earth.nullschool.net/#2019/05/02/1500Z/wind/surface/level/overlay=temp/orthographic=302.80,67.35,3000/loc=-50.155,66.615
Title: Re: Greenland 2019 Melt Season
Post by: johnm33 on May 02, 2019, 09:47:44 PM
The air is falling about 7000ft./2km and is probably bone dry, one of the few things I know about atmospherics is that as gas pressure increases it rises in temp. or have I got that wrong? Suggests some serious melt.
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on May 02, 2019, 09:52:03 PM
Can this temp anomaly on west Greenland be correct?

Temps > 12C

https://earth.nullschool.net/#2019/05/02/1500Z/wind/surface/level/overlay=temp/orthographic=302.80,67.35,3000/loc=-50.155,66.615

as per weather services and as it has been discussed over the last few days, yes
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 02, 2019, 10:13:20 PM
Can this temp anomaly on west Greenland be correct?

Temps > 12C
Could be - Nuuk, farther North, forecast max of 10 celsius next three days,
             - Ilulissat even farther North - max of 11 Saturday.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 03, 2019, 12:54:20 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 2 May 2019


I am looking at weatherforecast.com (as although https://climatereanalyzer.org/ came back it has gone again)

It looks like the West Coast will stay warm enough to keep the melt going at above or around 5% at least until Sunday. Early next week some above zero temperatures along the coast of the far north?
Title: Re: Greenland 2019 Melt Season
Post by: be cause on May 03, 2019, 01:52:26 PM
I don't think I've seen a forecast of over 20'C in May before . GFS has the west coast that warm in 60 hours .. meanwhile I'm shivering in Ireland .. :) .. b.c.
Title: Re: Greenland 2019 Melt Season
Post by: mabarnes on May 03, 2019, 05:42:16 PM
Hmmm....
Title: Re: Greenland 2019 Melt Season
Post by: ms on May 03, 2019, 08:24:11 PM
DMI should declare 'open season' on the melting season tomorrow as their criteria for 5% or greater melt extent for three consecutive days is all but assured to be met.

They heard you  :)
https://www.dmi.dk/?id=1042 (in danish)
http://polarportal.dk/en/news/news/greenland-melt-season-officially-starts-almost-a-month-early/
(in english)
Title: Re: Greenland 2019 Melt Season
Post by: be cause on May 04, 2019, 08:29:34 PM
Hmmm....

West Greenland forecast exceeds 16'C today .. 20'C tomorrow .. and 16'C monday and Tuesday .. they have made it warm in greenland ! :) .. here in Ireland .. -2'C last night and looking colder tonight .. b.c.
Title: Re: Greenland 2019 Melt Season
Post by: pauldry600 on May 05, 2019, 06:27:45 PM
Yes actually -3c in Sligo

The Arctics cold is spilling South.

Ice melt out wont happen for years and years yet as its only the outer layer of the ice that melts and even in mild weather its relatively slow but this aint good at all.

Look at it this way. In 50 years time Greenland will be a FAR different place.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on May 05, 2019, 07:11:28 PM
Yes actually -3c in Sligo

The Arctics cold is spilling South.

Ice melt out wont happen for years and years yet as its only the outer layer of the ice that melts and even in mild weather its relatively slow but this aint good at all.

Look at it this way. In 50 years time Greenland will be a FAR different place.

As the final repository of year round ice, Greenland is going to have a huge impact on NH climate and weather and not in a good way, I fear.
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on May 05, 2019, 08:40:32 PM
Yes actually -3c in Sligo

The Arctics cold is spilling South.

Ice melt out wont happen for years and years yet as its only the outer layer of the ice that melts and even in mild weather its relatively slow but this aint good at all.

Look at it this way. In 50 years time Greenland will be a FAR different place.

many years as a kind of joke a announced to buy land for my grand grand children in greenland, land that could even lay underneath a thin layer of ice up to this day.

as our family made wine for centuries, perhaps a nice greenland wine will be something in a few decades, who knows.

however, today i think the idea has to be considered in serious, just not too low ocean side because SLR should be put into account ;)
Title: Re: Greenland 2019 Melt Season
Post by: oren on May 05, 2019, 09:04:35 PM
Don't forget the gravitational effect. No SLR around Greenland - it will be the opposite.
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on May 05, 2019, 10:35:22 PM
Don't forget the gravitational effect. No SLR around Greenland - it will be the opposite.

ok, first time i didn't reply but since this is the second time i have to say that i disagree to that theory. even though there will be gravitational effects, i don't think that they will be +(X)x(Y) at the equator and (X)-(Z) at the poles. IMO SLR will be higher at the equator than towards the poles but no while  nevertheless everywhere on earth higher than now. ;)

perhaps we shall see the beginning of this effect either way, until now i did not come across any information that showed, other than the few cm of SL raises we already face by now each year, that up north and down south sea-level was sinking accordingly.

if the theory of zero raise (or lowering) could have a point, it would IMO apply to the geographical poles while the south pole is land anyways, hence what remains would be the north pole.

if you have that kind of information (measured not calculated) don't hesitate to link me to them, always interested to max input for proper assessment/opinion building ;)

Title: Re: Greenland 2019 Melt Season
Post by: oren on May 05, 2019, 11:09:29 PM
It's not an effect of north/south vs. equator but an effect of the mass of the Greenland ice sheet being so great that it is increasing local gravity near Greenland, and effectively causing a permanent high tide. When the ice sheet melts, global water level could rise by 6 or 7 meters, but near Greenland it will drop by tens of meters. I will look for an article on the subject.
Note: the same applies to Antarctica.
Note 2: there are also other effects such as rise of the surface after the weight of the ice is removed. An ice sheet is a super-massive thing.
Title: Re: Greenland 2019 Melt Season
Post by: oren on May 05, 2019, 11:14:22 PM
Read this, for example:
http://sealevelstudy.org/sea-change-science/whats-in-a-number/attractive-ice-sheets (http://sealevelstudy.org/sea-change-science/whats-in-a-number/attractive-ice-sheets)
Title: Re: Greenland 2019 Melt Season
Post by: RoxTheGeologist on May 06, 2019, 12:06:33 AM
Each meter of ice (at 1 g/cm3) will cause up lift 1*1/2.8 meters, assuming the rock replacing the ice has a density of 2.8 g/cm3. the isostatic reponse depends on the area of melt and the elastic strength of the lithosphere, but if it's over a broad enough area, the land covered, by, say, 1km of ice will experience up to 360m of uplift.
Title: Re: Greenland 2019 Melt Season
Post by: ghoti on May 06, 2019, 12:40:01 AM
From NASA ICE Facebook:

Quote
Today IceBridge flew its first science flight of the year from Kangerlussuaq, Greenland, titled ICESat-2 Central. This science flight begins only a short distance from town, and we were immediately stunned by the number and size of melt ponds on the ice-sheet surface. April temperatures in Greenland have been excessively high, leading to very early onset into the melt season. The melt ponds stole the show on an otherwise near featureless flight. As anticipated, the plane encountered frequent bouts of turbulence closer to the ice-sheet edge, which gradually reduced in duration as we migrated inland. This baseline mission surveys nine ICESat-2 tracks and flies over the sites of several shallow ice cores that were collected by the GreenTrACS project. Here's: 1. A blue melt pond with waves indicating the strength of today's wind. (NASA/Jefferson Beck) 2. A highly crevassed section of Russell Glacier with regions of exposed bare ice with bands of debris, snow, and newly formed melt ponds (NASA/Michael Studinger) 3. A look back towards the fjord where ice bends and breaks as it flows around a bedrock high. (NASA/Jefferson Beck) 4. Emerald green ponds weave around ice and debris near the terminus of Russell Glacier, which is experiencing anomalously early melt onset. (NASA/Brooke Medley)
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on May 06, 2019, 02:18:07 AM
It's not an effect of north/south vs. equator but an effect of the mass of the Greenland ice sheet being so great that it is increasing local gravity near Greenland, and effectively causing a permanent high tide. When the ice sheet melts, global water level could rise by 6 or 7 meters, but near Greenland it will drop by tens of meters. I will look for an article on the subject.
Note: the same applies to Antarctica.
Note 2: there are also other effects such as rise of the surface after the weight of the ice is removed. An ice sheet is a super-massive thing.

a) first i made a reading error, mixed gravitational with centrifugal force, a simple synaptic "misfire"

b) nevertheless and despite the source you provided i don't believe in that theory. while gravitation certainly has an impact it won't be that much on that scale to keep oceans significantly lower to prevent flooding IMO but the following will do that.

c) what indeed can prevent an SLR locally would be the raise of land through loss of ice-weight. that is something i forgot in my post and that part makes totally sense, it's not just a theory but a proven fact, observed in many enough places by geologists.

d) either way i did not expect or try to convince anyone of anything, i only wanted to let you know
that i heard about that theory and don's support it, hence it won't be necessary to mention it
in reply to my posts in form of a reminder.

we can easily agree to disagree on this matter, no problem and as i said, if that were true, the ocean would have to drop near antarctica and near greenland for each centimeter of SLR a few millimeters for the part those two contributed to SLR in a given period.

nevertheless i thank you for the link, it represents a theory but does not provide evidence of the kind that would change my mind ;)

since this is OT in this thread it's anyway better to end it here. i shall keep an eye on it and read a bit more often on that topic and let you know should something convince me in the future, funny by the way how a bit of kidding can make interesting questions surface.

Title: Re: Greenland 2019 Melt Season
Post by: sidd on May 06, 2019, 05:13:48 AM
Both Antarctic melt and GIS melt will SLR antipodally and sea level drop locally. This is very well established, look at any of the mitrovica papers. Challenging that effect is battling against arithmetic, unless of course, one wishes to challenge theory of gravitation instead.

sidd
Title: Re: Greenland 2019 Melt Season
Post by: kiwichick16 on May 06, 2019, 10:52:47 AM
the ice melt will happen much faster than the rebound of the land.....for example parts of Scotland are still rising as an after effect of the ice sheets melting

https://www.nature.scot/landforms-and-geology/scotlands-rocks-landforms-and-soils/landforms/coasts/present-and-future-sea-levels
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on May 06, 2019, 03:31:55 PM
The gravity effect seems reasonable to me.  Link to NASA video on sea level changes since 2002:

https://climate.nasa.gov/news/2626/evidence-of-sea-level-fingerprints/
 
Title: Re: Greenland 2019 Melt Season
Post by: oren on May 06, 2019, 04:12:53 PM
The gravity effect seems reasonable to me.  Link to NASA video on sea level changes since 2002:

https://climate.nasa.gov/news/2626/evidence-of-sea-level-fingerprints/
Thanks. Nice to see that not only it is expected in theory but that it has already been observed.
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on May 06, 2019, 04:13:25 PM
great input everyone, currently digesting and trying to weigh different explanations for the same phenomenon and the lifespan of the effect against each other

good for me to have a totally new topic to ponder over it and to ultimately make up my mind.

THX
Title: Re: Greenland 2019 Melt Season
Post by: RoxTheGeologist on May 06, 2019, 07:52:17 PM
the ice melt will happen much faster than the rebound of the land.....for example parts of Scotland are still rising as an after effect of the ice sheets melting

https://www.nature.scot/landforms-and-geology/scotlands-rocks-landforms-and-soils/landforms/coasts/present-and-future-sea-levels

Yes, but I'm not exactly sure where to buy my land to have good beach front property for my kids kids. PGR isn't fast, 2-5 cm a year, but that's 2 - 5 m over 100 years. It's not that much slower than SLR..But if you have 300 m to go, that's going to take 6000 years.

Gravitational attraction of masses on land have been know for a good long while! Look at the Great Trigonometrical Survey. When Everest mapped India he realized his plumb-lines were not hanging vertically and it was distorting the survey. The mass of the Himalaya was pulling them out of plumb.
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on May 06, 2019, 08:30:48 PM
the ice melt will happen much faster than the rebound of the land.....for example parts of Scotland are still rising as an after effect of the ice sheets melting

https://www.nature.scot/landforms-and-geology/scotlands-rocks-landforms-and-soils/landforms/coasts/present-and-future-sea-levels

Yes, but I'm not exactly sure where to buy my land to have good beach front property for my kids kids. PGR isn't fast, 2-5 cm a year, but that's 2 - 5 m over 100 years. It's not that much slower than SLR..But if you have 300 m to go, that's going to take 6000 years.

Gravitational attraction of masses on land have been know for a good long while! Look at the Great Trigonometrical Survey. When Everest mapped India he realized his plumb-lines were not hanging vertically and it was distorting the survey. The mass of the Himalaya was pulling them out of plumb.

perhaps i was not clear enough, it's not gravitation that i doubt, last thing i'd do, but since we're talking about over 50m of sea-level rise in total i really doubt that gravatation is able to compensate for the that amount of water.

i mean if we talk SLR we have to talk the end stage not transition phases in which we're already at this very moment.

i just can't see how this amount of mass could keep so much water back and then we would have to deal with some kind of through. i just don't get it for now how this could be the case but i've started to think, read and study because not everything that appears unlogical on first glance is not true and as a late student in astrophysics i'm certainly aware of this as well as gravitational effects. just not on that scale with that amount of mass/matter.

still grateful for your input bit curiosity is my main fuel to keep learning as a retired old fart LOL
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 06, 2019, 09:04:27 PM
Quote
just can't see how this amount of mass could keep so much water back
The 3,000 meter tall mountain of (mostly) ice that is Greenland is attracting water at this time.  As the ice melts (Greenland shrinks), it will attract less.

The NASA articled referenced by FrostKing (https://climate.nasa.gov/news/2626/evidence-of-sea-level-fingerprints/) - see the map below the GIF - shows an average sea level rise of 1.8 mm between 2002 and 2014 while the Greenland coast had a sea level fall of some 2.5 mm.  (The same is true for the part of Antarctica that is losing the most ice.)  (Some places had over 2 mm of sea level rise.)

The 'side-ways' force of gravity near big objects is not intuitively obvious [after all, gravity pulls us down!], but theoretically should be obvious [every bit of mass attracts equally (given equal distance)].  Surveying on the Pacific coast of South America is challenging because they have not only the tall Andes on the east (lots of rock where elsewhere there is air) but an oceanic trench on the west (lots of water where elsewhere there is rock).
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 06, 2019, 10:08:14 PM
Off-topic but could not resist.

Gravitational attraction of masses on land have been know for a good long while! Look at the Great Trigonometrical Survey. When Everest mapped India he realized his plumb-lines were not hanging vertically and it was distorting the survey. The mass of the Himalaya was pulling them out of plumb.

Investigations of the gravitational attraction of The Himalayas has contributed to the understanding of the earth's fluid mantle, isostasy, the less dense continents (SIAL) compared with the underlying SIMA, and plate tectonics.

For your edification here is a link to a paper giving the history and current state of play of Himalayan research in 1929 as presented to the Himalaya Club in their Journal.

https://www.himalayanclub.org/hj/01/6/the-attraction-of-the-himalaya/
Extract
Quote
In 1852 Everest invited the co-operation of the mathematician, Archdeacon Pratt of Calcutta, who made the first calculations of Himalayan attraction. Pratt very soon found that the agreement was in no way perfect and that the computed effect of the Himalaya at distant points was much greater than deflection actually found. This discordance provided the starting point of a most interesting investigation as to the structure of the Himalaya, which-extended to all other mountains--is very much alive to-day.
i.e. Himalayas had to have less mass than expected from its volume.
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on May 06, 2019, 10:19:13 PM
all true but millimeter scale agains i.e. 50+ meter scale are different things, as a mentioned above, i'm aware of gravity and it's effect but initially i was talking about assessing how far from sea to buy land for my grand grand children and they will see multiple meters of sea-level rise and not only a few millimeters, hence as true as all the elaborations are, they don't acount for SLR as it's usually discussed in this forum for > 100 years out.

also i find it interesting that all of the replies explain gravity which i said i'm aware, even know quite a lot about it in other contexts  but nobody directly replies to what will happen at the time i hinted through the "grand grand children" part, which will be in many decades from now and not in the millimeter range.

but no problem i'm going to calculate myself how much "attraction" through ice mass will get lost through ice loss and what the equivalent in water will be.

last but not least what i did also not hear about is that if the rest of the oceans are several meters higher across the board, there will be "water pressure" means higher waters will do their best to compensate the slope and that pressure must be huge and many times higher in force than the lost gravitational attraction through ice-loss in greenland.

also greenland will rise through loss of weight and in parts compensate ice loss through rock above surface gain (gravitation wise) because rock that is now i.e. 50 below ocean level will pull in another angle once it' will find itself 50m above sea-level (for example)

all the theories heard above may account for a few mm or cm but not for meters and not for dozens of meters of slope. i still don't take it as realistic because as we also know, gravitational force is reduced in relation to the the distance of  masses from each other:

If the mass of one of the objects is doubled, then the force of gravity between them is doubled. ... Since gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces.

https://www.ajdesigner.com/phpgravity/newtons_law_gravity_equation_force.php
Title: Re: Greenland 2019 Melt Season
Post by: oren on May 06, 2019, 10:37:38 PM
The moon has a small attraction on Earth and yet tides can change water level by meters.
But go ahead, make the calculation. I admit I've never done it myself. Bear in mind that the slope you mention is tens of meters divided by thousands of kilometers, so it's not as inclined as would appear intuitively.
I am not completely certain about the number itself. The only number I could easily find was 90m of local sea level drop if the whole of the West Antarctic Ice Sheet melted.
Title: Re: Greenland 2019 Melt Season
Post by: sidd on May 06, 2019, 11:29:58 PM
I repeat, as i did in another thread, look at the mitrovica papers. search for mitrovica on this forum or google scholar.

Re: "if the rest of the oceans are several meters higher across the board, there will be "water pressure" means higher waters will do their best to compensate the slope and that pressure must be huge and many times higher in force than the lost gravitational attraction through ice-loss in greenland."

No. The water surface is a gravitational + centrifugal equipotential. Please read mitrovica.

sidd
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on May 07, 2019, 12:01:04 AM
I repeat, as i did in another thread, look at the mitrovica papers. search for mitrovica on this forum or google scholar.

Re: "if the rest of the oceans are several meters higher across the board, there will be "water pressure" means higher waters will do their best to compensate the slope and that pressure must be huge and many times higher in force than the lost gravitational attraction through ice-loss in greenland."

No. The water surface is a gravitational + centrifugal equipotential. Please read mitrovica.

sidd

i've been reading it and it does not provide satisfactory proof, sorry.

it got a bit similar to the tesla thread, no direct answers to reasoning, ie. 50+ meters versus gravity force level = in favour of all other forces, they outweigh graviation by far.

etc. etc.

hence let's agree that we disagree and no satisfactory solution for all participants is in sight.

future will tell and i predict that sea-level in greenland will be higher in a few years/decades, perhaps i'll live to see it happen (or not LOL) chances are reduced so to say.

thanks again for all the input, there was either way a lot to take from it, no matter the details.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 07, 2019, 12:04:59 AM
I searched for you.  Here is a 2010 article, The Secret of Sea Level Rise: It Will Vary Greatly By Region (https://e360.yale.edu/features/the_secret_of_sea_level_rise_it_will_vary_greatly_by_region), that references a paper in Science.  The article includes:
Quote
if you own beachfront property in Iceland, and all of the ice on Greenland melts and adds seven meters to average sea level, you end up with more beach.

Of course, if all of Antarctica also melted, the 60 m or so additional sea level rise would affect Iceland (or remnants of Greenland), so best not to buy beachfront property anywhere but Antarctica (or maybe Patagonia) for your great-greats.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 07, 2019, 12:48:20 AM
Rising Oceans Guaranteed: Arctic Land Ice Loss and Sea Level Rise (https://link.springer.com/article/10.1007/s40641-018-0107-0)
Twila Moon, et al. - Arctic Climate Change  - 10 July 2018

Quote
The loss of gravitational pull caused by ice mass loss, along with vertical land motion associated with unweighting, means that sea level can fall locally (within ~ 2000 km of the location of ice mass loss) while rising in more distant locations [78].

Reference #79 includes
Quote
We lack robust forecasting models for future ice changes, which
diminishes our ability to use these fingerprints to accurately predict local sea-level (LSL) …
I guess your great-grand kids will have to fend for themselves!
Title: Re: Greenland 2019 Melt Season
Post by: sidd on May 07, 2019, 01:40:07 AM
1976 (Farrell and Clark, 1976 doi:10.1111/j.1365-246X.1976.tb01252.x )  give an approximation for a point ice mass, rigid earth

e(theta) = change of sea level = M_I*a/M_E * ( 1/(2sin(theta/2)) - 1 - rho_E/rho_w)

M_I=ice mass, M_E = earth mass , a = earth radius , theta = angular distance from ice , rho_E = density of earth, rho_w = density of water

Note that this approximation blows up at theta = 0. For small theta it correctly predicts rise in sea level and vice versa.

" when a point ice mass freezes from  ocean water, there is virtually no change in sea level 20 degrees away from the ice. Sixty degrees away sea level falls by exactly the  eustatic amount, but closer than 20 degrees, sea level actually rises. "

They do the elastic earth case and irregular masses also. (Greens functions, spherical harmonics, perturbation series ... )

The first detailed derivation for the general case of an extended ice (or other mass) which i can find  (although i am sure that someone like Kelvin or Raleigh worked it all out before) is Woodward in 1888 for a rigid earth. Read at

https://pubs.er.usgs.gov/publication/b48
https://pubs.usgs.gov/bul/0048/report.pdf

Warning: tedious math, but worth it. Familiarity with spherical harmonics, Legendre and other special functions required.

sidd



Title: Re: Greenland 2019 Melt Season
Post by: longwalks1 on May 07, 2019, 05:50:30 AM
Mitrovica   It is just dull plain Newtonian physics. 

youtube-dl   "https://www.youtube.com/watch?v=RhdY-ZezK7w"   

and

youtube-dl "https://www.youtube.com/watch?v=qD3-XCJATTU"

Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 07, 2019, 11:28:14 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 6 May 2019

As a bit of light relief from the gravity of the recent posts, just for a change here is some data about the Greenland 2019 Melt Season.

Melting
It looks like the West Coast especially will stay warm enough to keep the melt going at around 5% at least until Wednesday. After that it looks like melt will reduce but not stop.

Precipitation
It looks like precipitation is going to be below average over the next 10 days, but once again more in the SE coastal fringe.

The contrast between the highly +ve SMB  anomaly in the SE and the equally strong -ve anomaly in the West looks like becoming even more extreme.
Title: Re: Greenland 2019 Melt Season
Post by: johnm33 on May 07, 2019, 04:56:24 PM
The meltwater showing up in Baffin
(https://puu.sh/Dp4yG/414c5abbb6.jpg)
or zoom in on the hycom animation, https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsss_nowcast_anim30d.gif
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 08, 2019, 05:16:56 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 7 May 2019

Today I am feeling extra smug. There have been comments on some threads about forecasts made but no follow up. Here is a follow-up.

Some days ago I said that melt was likely to be significant for the time of year, and looked like persisting. I also said that if at the same time precipitation was low, there was a chance of a negative change to overall SMB, most unusual  for the time of year. On the 7th May this has occurred.

Melting
The melting on the 7th May was at a new maximum for 2019.
It looks like this could be repeated today the 8th May, but then reduce in the following days.

Precipitation
The 7th May was very dry indeed, with melt and sublimation on both East and West coastal fringes.

It looks like precipitation is going to be very much below average for at least the next week, with even the SE coast pretty dry.

SMB - Surface Mass Balance

On the 7th May Greenland lost a gigatonne or two Ok, only half a gt, of mass. This is over a month early compared with the average..

Today's weather conditions mean a repeat performance today is likely.

The contrast between the highly +ve SMB  anomaly in the SE and the equally strong -ve anomaly in the West looks like becoming even more extreme.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 08, 2019, 05:46:01 PM
Congratulations, Mr. Smug ('Extra', to personal friends).   :)
Except that early ice mass loss is bad news for us Earthlings.  :'(

[Yeah, I know you didn't say you were extra smug, just feeling him or her, but I didn't want to go there.  If people capitalized their handles, we'd know if 'extra smug' was a somebody or just an emotion.  Speaking English as an American (okay, a citizen of the U.S.A.), I'm extra handicapped.  But do enjoy your day!]
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 08, 2019, 06:13:44 PM
Congratulations, Mr. Smug ('Extra', to personal friends).   :)
I don't get to see Extra Smug very often these days. Usually it's Wrong Completely Wrong. It is less than 2 months since the Arctic Sea Ice extent maximum.  That is one forecast better buried deep. My ego is still in tatters.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 10, 2019, 12:10:32 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 9 May 2019

The 9th May was the third day of negative change (although very small) to overall SMB, most unusual  for the time of year.

Melting
Melting is still high for the time of year.
However, from the 14th it looks like warmth returns to  Baffin Bay with a vengeance, and persisting for rest of the 10 day forecast period

Precipitation
The 7th to 9th May was very dry indeed, with melt and sublimation on both East and West coastal fringes.

It looks like precipitation is going to be very much below average for at least the forecast period, apart from the SE coast. At low altitudes methinks some of that will be rain, not snow.

SMB - Surface Mass Balance

So for 3 days Greenland lost a few hundred million tonnes of mass, instead of gaining the average of around 2 gt per day.mass. This is over a month early compared with the average..

The contrast between the highly +ve SMB  anomaly in the SE and the equally strong -ve anomaly in the West looks like becoming even more extreme.

The next 10 days are likely to be interesting as warmth and cold wax and wane, wane and wax.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 10, 2019, 04:54:53 PM
Sleepy posted (https://forum.arctic-sea-ice.net/index.php/topic,1537.msg198619.html#msg198619) a global daily 'normal' precipitation GIF.  I've extracted the approx. minimum and maximum images for Greenland.  It shows that the north or northwest is basically a desert and the southeast is 'wet'.  Also, the wet season for much of Greenland goes from (approximately) August through February while the dry season is only April and May.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 11, 2019, 12:21:56 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 10 May 2019

Melt was lower, but precipitation was minimal so the 10th May was the fourth day of negative change (although very small) to overall SMB, most unusual  for the time of year.

This is becoming apparent on the accumulated SMB graph.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 12, 2019, 01:15:23 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 11 May 2019

Melt was lower again, but precipitation was nearly zero so 11 May was the fifth day of negative change (although very small) to overall SMB, most unusual  for the time of year.

This is becoming apparent on the accumulated SMB graph.

From Tuesday onwards it looks like melt will tick up, while precipitation will remain low, so SMB change should be -ve or close to zero..
_____________________________________________________
ps: Note how that warmth is spread over most of Baffin Bay, Hudson Bay and much of the eastern CAA.
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on May 12, 2019, 04:28:00 PM
Off-topic, but these temperatures also should affect Hudson Bay Sea ice seriously, at least in its southern tip...
Title: Re: Greenland 2019 Melt Season
Post by: vox_mundi on May 12, 2019, 08:42:56 PM
Airborne NASA Scientists Just Filmed Something Troubling In Greenland
https://mashable.com/article/greenland-melt-2019-climate-change/

(https://mondrian.mashable.com/uploads%252Fstory%252Fthumbnail%252F96085%252F58443a0f-564f-449e-be2c-b4c1cfd9a644.jpg%252F560x316.jpg)

Scientists aboard a NASA airplane swooped over some of Greenland's largest glaciers on Monday, spotting melted ice and raging rivers.

It's significant, because though it's not nearly summer, large blue ponds have already formed on the icy ground. NASA’s Operation IceBridge researchers observed this as part of their mission to watch for changes in Earth’s giant masses of polar ice. Greenland, in particular, has been melting at an accelerated rate for some two decades.

"Although the story of the summer of 2019 in Greenland hasn’t yet been written, it's starting on a worrying note," said Joe MacGregor, the project scientist for Operation IceBridge.

While such profound early season melting isn't unprecedented, typically these melt ponds form in late May to early June, explained MacGregor. This spring, there's one obvious culprit: really warm temperatures. Last week in Greenland — one of the coldest parts on Earth — temperatures measured in the upper 50s to low 60s Fahrenheit, he said.

MacGregor is on land in the U.S., but his IceBridge colleague, glaciologist Brooke Medley, captured footage of the early melt creating big pools of water, seen below.

(https://pbs.twimg.com/ext_tw_video_thumb/1125873300142460928/pu/img/h1mv0WVR2nDaytMv?format=jpg&name=small)
https://twitter.com/DrBrookeMedley/status/1125873350448906240

https://twitter.com/i/videos/1125873350448906240

@NASA #IceBridge ✈ observed surface melt north of Jakobshavn ... While the blue water is breathtaking, the early onset of melt over Greenland is concerning for Earth ... "Concerning" - what a uselessly weak verb. Totally fails to convey the gravity of these images ... meltwater ponds also visible on Landsat/Sentinel/Modis pics...caused by record breaking warmth since end of April (Kangerlussuaq up to19deg C).

(https://pbs.twimg.com/media/D5_CKIPWkAAn_9s.jpg)
A mosaic from the CAMBOT instrument on #IceBridge shows a melt pond with surface rippling, as seen on Sunday's flight.

(https://pbs.twimg.com/media/D5_C2IRWAAIkLM3.jpg)

From Sunday's #IceBridge flight: Emerald green ponds weave around ice and debris near the terminus of Russell Glacier, which is showing signs of an early onset into the melt season

"The melt has the potential to accelerate," said MacGregor.

------------------------------------

Tsunami Signals to Measure Glacier Calving in Greenland
https://www.sciencedaily.com/releases/2019/05/190508093748.htm

Scientists have employed a new method utilizing tsunami signals to calculate the calving magnitude of an ocean-terminating glacier in northwestern Greenland, uncovering correlations between calving flux and environmental factors such as air temperature, ice speed, and ocean tides.
Title: Re: Greenland 2019 Melt Season
Post by: vox_mundi on May 13, 2019, 01:53:12 AM
https://mobile.twitter.com/ZLabe/status/1125073637797552129

Zack Labe: Well above average temperatures across all of #Greenland over the last week. Follow forecasts for Greenland (weather and surface mass balance) this summer using the MARv3.9 model (forced by GFS) at http://climato.be/cms/index.php?climato=the-2019-melt-season-over-greenland-as-simulated-by-marv3-9

(https://pbs.twimg.com/media/D50PdA5UEAEFHAS?format=jpg&name=small)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fclimato.be%2Fuser%2Ffettweis%2Fimg%2F2019-SMB-fig1.png&hash=540affec587e0580362f28e672f57cda)
See http://climato.be/cms/index.php?climato=the-2019-melt-season-over-greenland-as-simulated-by-marv3-9 for description.

NASA IceBridge: Scientists film twin troubles plaguing Greenland's melting glaciers   
https://www.google.com/amp/s/www.firstpost.com/tech/science/nasa-icebridge-scientists-film-twin-troubles-plaguing-greenlands-melting-glaciers-6599841.html/amp
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 13, 2019, 09:16:01 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 12 May 2019

Melt was lower yet again, but precipitation was nearly zero so 12 May was the sixth day of negative change (although very small) to overall SMB, most unusual  for the time of year.

This is becoming even more apparent on the accumulated SMB graph.

From Tuesday onwards it looks like melt will tick up, while precipitation will remain low, so SMB change should be -ve or close to zero..
_____________________________________________________
ps: For newcomers. SMB = Surface Mass Balance, i.e. looks at precipitation and melting only. Mass loss from calving from glaciers and ice shelves is NOT included.

pps: The unusual happenings on Greenland are stirring interest in the scientific community. This thread might be getting quite lively.

pppps: NASA still promising mass change data from this summer - and it might go part of the way backwards to fill part of the missing data from early 2017.
Title: Re: Greenland 2019 Melt Season
Post by: oren on May 13, 2019, 11:48:11 AM
After an ominous SMB winter, April saw a large catch up, but the last week is giving me that nasty feeling again.
When will GRACE data finally be published??
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 13, 2019, 12:34:51 PM
After an ominous SMB winter, April saw a large catch up, but the last week is giving me that nasty feeling again.
When will GRACE data finally be published??
From https://media.gfz-potsdam.de/gfz/sec12/pdf/GRACE_FO_SDS_newsletter_No2.pdf
@
https://www.gfz-potsdam.de/en/section/global-geomonitoring-and-gravity-field/projects/gravity-recovery-and-climate-experiment-follow-on-grace-fo-mission/
Quote
Since launch (May-22, 2018), GRACE-FO has collected approximately 7 months of the science
data which will be part of the first Level-1A/B data scheduled for release on or before May 28,
2019. The Level-2 gravity products and the observations from the LRI (Laser Ranging
Interferometer) technology demonstration will be released as planned on or before July-27,
2019. The Science Data System will release the data through the US PO.DAAC
(http://podaac.jpl.nasa.gov) and the German ISDC (https://isdc.gfz-potsdam.de/grace-fo-isdc)
data portals (see important updates for PO.DAAC data access below). Detailed documentation
of the Level-1 data processing and the adopted calibration strategies will be released
concurrently with the data.
Title: Re: Greenland 2019 Melt Season
Post by: Alexander555 on May 13, 2019, 02:40:23 PM
The unusual happenings, that's the early melt/mass loss on Greenland ?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 13, 2019, 02:52:04 PM
The unusual happenings, that's the early melt/mass loss on Greenland ?
What is unusual is that Surface Mass should start to reduce this early. Normally the Surface Mass increases as snow continues to fall that outweighs surface melting for about another month. However, in a normal year total snowfall exceeds total surface melting, so Greenland accumulates additional surface mass of around 400gt.

Meanwhile glaciers calve and wend their way into the ocean at normally over 600 gt per annum. This normally exceeds gain in surface mass by at least 200 gt in each year. the GRACE project give us the accurate figure for this net mass loss.

 Read the blurb at http://polarportal.dk/en/greenland/surface-conditions/
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 14, 2019, 01:23:57 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 13 May 2019

Melt
Melt was lower again, but looks like getting a bit more vigorous over the next week or so as pulses of warmth enter Baffin Bay and occasionally the East Coast up the Greenland sea.

Precipitation
Precipitation was nearly zero on 13 May. But although melt was quite low and confined to the fringe, there was considerable sublimation, extending further inland in the SW.

It looks like precipitation may return to something like normal, i.e. mostly falling in the SE, progressively drier North and West. The question is (to me) how much of that precipitation in the South East will fall as rain?

Overall SMB

the 13th May was the sixth day of negative change (although very small) to overall SMB, most unusual  for the time of year. This is becoming very apparent on the accumulated SMB graph.

The SMB -ve anomaly in the West contrasts ever more strongly with the +ve SMB anomaly in the SE.

My forecast (gulp) is for daily -ve SMB to continue and possibly increase.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 15, 2019, 11:32:03 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 14 May 2019

Precipitation outweighs melt on this day.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 17, 2019, 10:57:10 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 16 May 2019

16 May Precipitation outweighs melt on this day, but not by much.

Next 10 days Looks like melt to continue at around the same level, and precipitation to be fairly low. So perhaps overall SMB gain to be below average.
Title: Re: Greenland 2019 Melt Season
Post by: Observer2019 on May 17, 2019, 11:59:06 AM
Question: How can there be melt in areas where the temps are showing under -10c ?
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 18, 2019, 10:23:47 AM
Greenland Melt off to a Fast Start in 2019

https://www.youtube.com/watch?v=fDpJv2o7BhA
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 18, 2019, 10:35:33 AM
Question: How can there be melt in areas where the temps are showing under -10c ?

Hello and welcome to the forum. :)

There is a lot of sunlight in the Arctic these days. Even if the ice looks very white, the albedo is not 100%. If you have a dark underground, for example, energy will be absorbed. Or dark particles that sit on the ice are warming and with them the ice around.

Air pressure is a factor moving the melting point of water slightly.
Title: Re: Greenland 2019 Melt Season
Post by: oren on May 18, 2019, 12:27:07 PM
There's also sublimation - ice turning to water vapor under the effects of wind and sunlight.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 18, 2019, 02:28:20 PM
Ah, and there is also rain. If it rains below zero, snow and ice would melt.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 18, 2019, 02:45:59 PM
As the reported temperatures are based on models with few ground-truthing opportunities, some local temperatures (especially on a slope receiving more direct sunshine that hour) will be higher than 'reported' (Edit: although 10C may be a stretch - see below; proof I'm not an expert!).  Of course, lower 'actual' temperatures are equally possible (especially when a slope is in shade).  [note: I am not writing as an expert in such things.]
Title: Re: Greenland 2019 Melt Season
Post by: vox_mundi on May 18, 2019, 02:56:24 PM
Add foehn winds to the equation ...
https://en.m.wikipedia.org/wiki/Foehn_wind

(https://weatheraction.files.wordpress.com/2017/02/wp-image-507876500png.png?w=700)

Föhn winds can raise temperatures by as much as 14 °C (25 °F)[4] in just a matter of minutes.

Winds of this type are also called "snow-eaters" for their ability to make snow and ice melt or sublimate rapidly. This is a result not only of the warmth of foehn air, but also its low relative humidity.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 18, 2019, 03:43:03 PM
(although 10C may be a stretch)

Not necessarily. The Amery Ice Shelf region in Antarctica is melting in summer even with temperatures at -20˚C and below.

Like here in this last clear Sentinel shot from February >>https://apps.sentinel-hub.com/sentinel-playground/?source=S2&lat=-72.19325109680253&lng=68.45306396484375&zoom=11&preset=CUSTOM&layers=B01,B02,B03&maxcc=20&gain=1.0&gamma=1.0&time=2018-08-01%7C2019-02-21&atmFilter=&showDates=false&evalscript=cmV0dXJuIFtCOEEqMSxCMDMqMSxCMDIqMV0%3D

(not an expert either!)
Title: Re: Greenland 2019 Melt Season
Post by: Carex on May 19, 2019, 12:03:50 AM
Another little twist is that the air temp is measured and modeled at 1.5m or 2m above the surface.  Much of the energy from solar radiation will pass through the air but be absorbed by the surface, especially where dirt and soot are present.  Light isn't converted to heat until it is absorbed.  So the surface can warm and start to melt while the air 2m above it is still below freezing.  On slopes facing the sun the effect will be greater as the solar angle to the surface increases.  I'm sure this can be said much more scientifically. 
Title: Re: Greenland 2019 Melt Season
Post by: magnamentis on May 19, 2019, 01:50:27 AM
Another little twist is that the air temp is measured and modeled at 1.5m or 2m above the surface.  Much of the energy from solar radiation will pass through the air but be absorbed by the surface, especially where dirt and soot are present.  Light isn't converted to heat until it is absorbed.  So the surface can warm and start to melt while the air 2m above it is still below freezing.  On slopes facing the sun the effect will be greater as the solar angle to the surface increases.  I'm sure this can be said much more scientifically.

this is 100% correct and well explained which is all that's necessary. we don't all need doctorates to understand more than what's in hour palmares and/or diplomas ;)

BTW even ice is melting under the sun at temps way below zero at this time of the year. a good source for those who don't live in typical ice and snow covered areas would be webcams like the one in barrows
Title: Re: Greenland 2019 Melt Season
Post by: wdmn on May 19, 2019, 02:51:51 AM
Yeah, the north side of a road, which is not shaded, melts much faster than the south side, which does not get any sun. Just as the areas without trees melt much more quickly than the forested areas.

Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 19, 2019, 01:41:02 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 18 May 2019

16 to 18 May Precipitation outweighs melt on these days, but not by much.

Next 5 days Looks like melt to continue at around the same level, and precipitation to be fairly low. So perhaps overall SMB gain to be below average, maybe even -ve on one or two days.

______________________________________________
NOTES
- the DMI and NSIDC models both try to make allowances for melt / rain that refreezes / freezes where it happens, i.e. does not run-off the ice-sheet and reduce mass.
- they are models, but are tested against real observations from weather stations and other field data. Mind you, I believe the NSIDC and DMI models did end up with markedly different results about the amount of above average SMB  in the 2018-19 Greenland year.
- they are the best we have - and even if in error, are consistent over time which gives the direction of travel. Last 2 years - high above average SMB gain - this year, well below average so far.
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on May 19, 2019, 09:42:22 PM
Update of weather and forecast in Narssarsuaq, South Greenland. Melting all the time. Much sun and, possibly later next week, some rain. Not good for the ice in that area...
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 20, 2019, 01:58:18 AM
Further north, not so warm, but expect some sunshine next week (and therefore some melt on sun-facing slopes).  Hans Island (https://www.meteoblue.com/en/weather/forecast/14-days/hans-island_canada_5970356) is in Nares Strait.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 20, 2019, 11:22:43 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 19 May 2019

16 to 19 May Precipitation outweighs melt on these days, but not by much.

Next 5 days Looks like melt to continue at around the same level (warm afternoons, and precipitation to be fairly low and confined to the SE. So perhaps overall SMB gain to be below average, maybe even -ve on one or two days.

During / after next weekend looks like a weather change. Warmth, rain and snow from the south enters Baffin Bay and impacts the west coast of Greenland. It is that balance between rain and snow that will determine the change in SMB? (See also post by Sleepy above)
______________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 21, 2019, 12:34:32 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 19 May 2019

16 to 20 May Precipitation outweighs melt on these days, but not by much.
The weekly update of the accumulated SMB anomaly is also attached. +ve  noamlies are alsmost totally confined the the coastal fringe of the SE. The contrast between the dry NW and the wet SE is much higher than average.

Next 5 days Looks like melt to continue at around the same level (warm afternoons, and precipitation to be fairly low and confined to the SE. So perhaps overall SMB gain to be below average, maybe even -ve on one or two days.

During / after next weekend looks like a weather change. Warmth, rain and snow from the south enters Baffin Bay and impacts the west coast of Greenland. It is that balance between rain and snow that will determine the change in SMB? (See also post by Sleepy above)
______________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 22, 2019, 01:33:06 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 21 May 2019

16 to 21 May Precipitation outweighs melt on these days, but not by much.

Next 10 days The GFS forecast has changed a lot. It now looks as if Greenland will be very dry, with even the SE looking much dryer than average. With above zero temperatures on much of the East and West coastal fringes in the long afternoons, my prediction that belongs to me is that there will be an occasional day of SMB loss.
Title: Re: Greenland 2019 Melt Season
Post by: Tealight on May 22, 2019, 11:43:21 PM
Even if we have slightly more melt than precipitation right now. Most losses are happening in June and July. On the attached gif I compared the 10th July 2012 with today. It almost looks like we have no melt right now.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 22, 2019, 11:57:41 PM
Even if we have slightly more melt than precipitation right now. Most losses are happening in June and July. On the attached gif I compared the 10th July 2012 with today. It almost looks like we have no melt right now.
What we have at the moment is much lower SMB gain compared with both the average and 2012..In June and July 2012 SMB fell off a cliff. All one can say is that this year as at May 21 is perhaps ahead of the game compared with 2012 - darker surface at least on the fringes where melt has been quite strong and very persistent.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 23, 2019, 07:19:48 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 22 May 2019

16 to 21 May Precipitation outweighs melt on these days, but not by much.
22 May Melt outweighs precipitation on this day, by a smidgeon.

Next 10 days The GFS forecast still saying Greenland will be very dry, with even the SE looking much dryer than average. With above zero temperatures on much of the East and West coastal fringes in the long afternoons, my prediction that belongs to me is that there will be more occasional days of SMB loss.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 23, 2019, 02:31:57 PM
Quote
Next 10 days The GFS forecast still saying Greenland will be very dry, with even the SE looking much dryer than average.
Per Reply #100 (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg198672.html#msg198672), this "dryer than average" is quite expected, climatologically.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 24, 2019, 04:11:26 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 23 May 2019

16 to 21 May Precipitation outweighs melt on these days, but not by much.
22 May Melt outweighs precipitation on this day, by a smidgeon .
23 May Melt outweighs precipitation on this day, by more than a smidgeon .

Next 10 days The GFS forecast still saying Greenland will be very dry, with even the SE looking dryer than average. With above zero temperatures on much of the East and West coastal fringes in the long afternoons, my prediction that belongs to me is that there will be more occasional days of SMB loss.

The persistence of melt, and the persistent low precipitation is unusual, hence the accumulated SMB gain in the 2018-19 year at circa 60 GT below average, in contrast to the above average gains in the previous 2 years.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 25, 2019, 09:49:48 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 23 May 2019

16 to 21 May Precipitation outweighs melt on these days, but not by much.
22 May Melt outweighs precipitation on this day, by a smidgeon .
23 May Melt outweighs precipitation on this day, by more than a smidgeon .
24 May Melt outweighs precipitation on this day, by even more than more than a smidgeon .

Next 10 days The GFS forecast still saying Greenland will be very dry, with even the SE looking dryer than average. With above zero temperatures on much of the East and West coastal fringes in the long afternoons, my prediction that belongs to me is that there will be yet more occasional days of SMB loss.

The persistence of melt, and the persistent low precipitation is unusual, hence the accumulated SMB gain in the 2018-19 year at circa 60 GT below average, in contrast to the above average gains in the previous 2 years.
Title: Re: Greenland 2019 Melt Season
Post by: Sailaway on May 25, 2019, 11:52:01 AM
Just for clarification are we talking about Metric or Imperial Smidgeon

Thanks
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 25, 2019, 12:17:25 PM
Just for clarification are we talking about Metric or Imperial Smidgeon

Thanks
There are 2,204.62 pounds in a Metric ton.
There are 2,240 pounds in an Imperial tonne.
There are 2,000 pounds in a US ton (lightweights!).

So difference not relevant when considering smidgeons, as in the US of A there are no smidgeons, only smidgens.. The 24th May SMB loss was just over 1 thousand million  (1,000,000,000 ) tonnes of smidgeons (1 GT or 1 KM3 of water).
______________________________________________

ps: The dictionary used by the ASIF is American - huh.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 25, 2019, 01:33:08 PM
If you thought you were mixing metaphors, you're right.  Those pounds in a metric ton are at sea level.  If the smidgeons are in Greenland, shouldn't they be called lille beløb [if Google is any help] and as many of them are atop the icecap, then your decimal places are wrong (even the 4 should be a 3!). 'Cause water boils at ~90C at 10,000 feet, but the factor is different.  So just get your units lined up and straights! ::) 8) :o :-\  Edit: and nearly everybody has 'feet' and only engineers and the like have 'meters'.  so there! >:(

But I do like the sound (in my imagination, as I know no Danish) of lille beløb! :-*
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on May 25, 2019, 01:45:04 PM
 :o
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 26, 2019, 01:08:43 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 25 May 2019

16 to 21 May Precipitation outweighs melt on these days, but not by much.
22 May Melt outweighs precipitation on this day, by a smidgeon .
23 May Melt outweighs precipitation on this day, by more than a smidgeon .
24-25 May Melt outweighs precipitation on this day, by even more than more than a smidgeon. SMB daily mass loss of 1 GT instead of mass gain of 2GT.

Next 10 days The GFS forecast still saying Greenland will be very dry, with even the SE looking extremely dry. Some, but not much precipitation drifting into the North East.  Very good conditions for insolation (that's sunshine all day and night 24/7). With above zero temperatures on much of the East and West coastal fringes in the long afternoons, my prediction that belongs to me is that there will be yet more days of SMB loss.

The persistence of melt, and the persistent low precipitation is unusual, hence the accumulated SMB gain in the 2018-19 year at circa 60 GT below average, in contrast to the above average mass gains in the previous 2 years.
Title: Re: Greenland 2019 Melt Season
Post by: silkman on May 26, 2019, 01:10:50 PM
Even if we have slightly more melt than precipitation right now. Most losses are happening in June and July. On the attached gif I compared the 10th July 2012 with today. It almost looks like we have no melt right now.

Here's a May 25th Worldview image of the area just to the South of Disko Bay showing a substantial number of melt ponds and an indication of decreasing albedo. It seems that the melt season is now well under way.

https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2019-05-25-T00%3A00%3A00Z&z=3&v=-261605.09040728386,-2356810.180814568,-130533.09040728386,-2270794.180814568
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 26, 2019, 01:37:13 PM
And 2 images 4 days apart from Sisimiut area showing bare ground appearing where once was snow.

courtesy of DMI @ http://ocean.dmi.dk/arctic/sisimiut.uk.php (Hours of playtime here)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 27, 2019, 12:29:40 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 26 May 2019

Greenland is melting - early
Title: Re: Greenland 2019 Melt Season
Post by: oren on May 27, 2019, 01:20:25 PM
Damn. It almost feels as if SMB for the season has peaked. It's not really the melt which isn't extraordinary, just normal, so it must be the lack of sufficient precipitation that's taking it so low.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on May 27, 2019, 01:36:42 PM
Earlier onset of melt and lower ending SMB than 2012. Wasn't 2012 a dreadful year for Greenland melt?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 27, 2019, 02:47:54 PM
Earlier onset of melt and lower ending SMB than 2012. Wasn't 2012 a dreadful year for Greenland melt?
Look at the graph in the post above. Yes, 2012 was extraordinary - and just as for sea ice, 2012 melt started late.

in 2019, melt is starting early after somewhat less than average snowfall mass gain.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 27, 2019, 03:06:43 PM
Images from Sisimiut on the West Coast
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 27, 2019, 03:21:33 PM
One month of Sisimiut via Worldview:
Title: Re: Greenland 2019 Melt Season
Post by: Mr. Ä on May 27, 2019, 05:40:49 PM
So much sediment flowing to the fjords already. And new dark ground being uncovered every day. Looks like it could be a bad year for Kangerlussuaq harbor.
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on May 27, 2019, 07:52:52 PM
Early melting also on Greenland's eastern side.
The webcam image shows two melt ponds on Freya Gletscher, located at an altitude of 1.053 m asl on an island south of Zackenberg Bay. I added the coordinates into the picture.
In 2016 the first melt pond was visible on June 13, in 2017 it was June 6.
2018 had no pictures, the webcam was out of service from May 3 on.
Unfortunately there are no older pictures available.
Link to the website: https://www.foto-webcam.eu/webcam/freya1/2017/06/04/1200
See attached photo
Title: Re: Greenland 2019 Melt Season
Post by: oren on May 28, 2019, 05:43:47 AM
Beautiful webcam, thanks for the link.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 28, 2019, 12:21:19 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 27 May 2019

Weekly accumulated SMB anomaly map attached.

16 to 21 May Precipitation outweighs melt on these days, but not by much.
22 to 27 May Melt outweighs precipitation on these days.

Next 10 days The GFS forecast still saying Southern Greenland will be very dry, with even the SE looking extremely dry. Precipitation coming into the North - I don't think that is usual. 

Very good conditions for insolation in the Southern half (that's sunshine all day and night 24/7). Above zero temperatures on the East and especially the West coastal fringes (and Baffin Bay) in the long afternoons.  My prediction that belongs to me is that there will be yet more days of SMB loss (unless outweighed by increasing precipitation in the North later in the forecast period).

The persistence of melt, and the persistent low precipitation is unusual, hence the accumulated SMB gain in the 2018-19 year at circa 60 GT below average, in contrast to the above average mass gains in the previous 2 years.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 28, 2019, 04:01:37 PM
Quote
The persistence of melt, and the persistent low precipitation is unusual

From climatology (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg198672.html#msg198672), I think the melt is unusual, but not the lack of precipitation.  If low precipitation continues through June, that would be unusual.  See Sleepy's 'original post (https://forum.arctic-sea-ice.net/index.php/topic,1537.msg198619.html#msg198619)' to see the whole year's daily average precipitation GIF.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 29, 2019, 08:07:53 AM
That looks like a lot of water discharging downhill from melt ponds?

I would agree. The whole ice sheet border area is thawing.

return [B8A*1, B03*1,B02*1] gives you a nice blue tint for melting snow and ice.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 29, 2019, 08:37:22 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 28 May 2019

16 to 21 May Precipitation outweighs melt on these days, but not by much.
22 to 28 May Melt outweighs precipitation on these days.

Next 10 days For the first 5 days the GFS forecast still saying Southern Greenland will be very dry, with even the SE looking extremely dry. After that precipitation coming into the North and then also from the  South. 

Very good conditions for insolation in the Southern half to begin with (that's sunshine all day and night 24/7). Above zero temperatures on the East and especially the West coastal fringes (and Baffin Bay) in the long afternoons.  My prediction that belongs to me is that there will be a few more days of SMB loss until  outweighed by increasing precipitation later in the forecast period.

The accumulated SMB gain in the 2018-19 year is well below average, in contrast to the above average mass gains in the previous 2 years.
_________________________________________________________
Quote from DMI Polar Portal....
Note, when comparing with the surface mass balance under ”Daily change”, that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 30, 2019, 10:59:27 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 29 May 2019

16 to 21 May Precipitation outweighs melt on these days, but not by much.
22 to 29 May Melt outweighs precipitation on these days.

Next 10 days The GFS forecast still saying Greenland will be mostly dry, with even the SE looking extremely dry. Some moderate precipitation on the West coast half-way up Baffin Bay.

Good conditions for insolation in general (that's sunshine all day and night 24/7). Above zero temperatures on the East and especially the West coastal fringes (and Baffin Bay) in the long afternoons.  But no indication that melt will increase substantially. Note that some of the daily SMB loss is due to sublimation. See note below.

My prediction that belongs to me is that there will be more days of SMB loss but becoming closer to the average daily SMB change.

The below average SMB accumulated gain for the 2018-19 year is still increasing, in contrast to the above average mass gains in the previous 2 years.
_________________________________________________________
Quote from DMI Polar Portal....
Note, when comparing with the surface mass balance under ”Daily change”, that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 31, 2019, 11:28:03 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 30 May 2019

16 to 21 May Precipitation outweighs melt on these days, but not by much.
22 to 29 May Melt outweighs precipitation on these days.

30 May Precipitation outweighs melt on this day, but not by much.

Next 10 days The GFS forecast still saying Greenland will be mostly dry, with even the SE looking extremely dry. Some moderate precipitation on the West coast.

Good conditions for insolation in general (that's sunshine all day and night 24/7). Above zero temperatures on the East and especially the West coastal fringes (and Baffin Bay) in the long afternoons.  But no indication that melt will increase substantially. Note that some of the daily SMB loss is due to sublimation.

The below average SMB accumulated gain for the 2018-19 year is still increasing, in contrast to the above average mass gains in the previous 2 years.
_________________________________________________________
My prediction that belongs to me is that there will be more days of SMB loss but becoming much closer to the average daily SMB change. Given this reversion to far more average daily change, postings will be reduced to the weekly update of the accumulated SMB anomalies map.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 31, 2019, 04:04:02 PM
How we already know 2019 will be a big melt year for Greenland

https://www.youtube.com/watch?v=br9N_Cqmfz0
Title: Re: Greenland 2019 Melt Season
Post by: oren on May 31, 2019, 04:46:48 PM
How we already know 2019 will be a big melt year for Greenland
I must say this is quite disturbing.
Does anyone know if the station data quoted in the video is available somewhere online?
(Albedo, snow depth, temperature).
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 31, 2019, 05:47:40 PM
How we already know 2019 will be a big melt year for Greenland
I must say this is quite disturbing.
Does anyone know if the station data quoted in the video is available somewhere online?
(Albedo, snow depth, temperature).
Go to http://polarportal.dk/en/greenland/surface-conditions/

Choose a weather station (e.g. ) and
Quote
"By holding the mouse over the circles, you can see the day’s weather observations from meteorological stations that are used to monitor the melting processes.
Albedo not available by individual stations, but certainly as a map updated quite often with slider on main DMI site.

Click on "See Details at GEUS" and you get loads of stuff, not just about the weather stations, but about just about everything to do with the Greenland Ice Sheet.. Indeed, I had not a clue all this stuff was there.
_______________________________________________________________________
This year is different from the last 2 years - and perhaps it was the last 2 years that were the aberration. see last image - can't remember from whence it came - SIDC Greenland Today?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 31, 2019, 06:12:36 PM
Re video above...
So there was I thinking that perhaps things were getting to look much more like average, and then the guy from DMI tells us the early melt has pre-conditioned the Greenland surface for a major melt year.



Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 31, 2019, 06:31:11 PM
My takeaway from the video was the point that we are so far ahead of 2012 this year.

But yes, they kinda cherrypicked that NUK region there and made extrapolations.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on May 31, 2019, 06:38:43 PM
Re Oren posting the Jason Box explanation that 2019 does not look good for Greenland's ice:  how can one "like" such bad news?  (But I'm grateful anyway.)

By the way, if you search for "Jason Box" in the ASIF Search, you'll get some 30 references to him starting in 2013.  (OT: I don't like that he sees geoengineering as something we must do, but it may be the only way to avoid 4C - but unless the geoengineering lowers CO2 concentrations, the oceans will become toxic.) 
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on May 31, 2019, 07:34:45 PM
How we already know 2019 will be a big melt year for Greenland
Thanks for sharing this important information with us.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on May 31, 2019, 07:37:08 PM
Welcome Stephan :)
Title: Re: Greenland 2019 Melt Season
Post by: sidd on May 31, 2019, 09:51:19 PM
Re:  difference between "average" and "mean"

educate me please ?

sidd
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on May 31, 2019, 09:57:05 PM
Oops, I confused "mean" and "median"!

An example with a small data set:

Data :  1,2,3,16,18

This data set has 5 data points which sum to 40.

The average is the sum divided by the number of data points so 40/5 = 8, which is the same as the mean

The median is the middle number when the data is arranged numerically, so the median for this data set is 3
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on May 31, 2019, 10:36:49 PM
Oops, I confused "mean" and "median"!

An example with a small data set:

Data :  1,2,3,16,18

This data set has 5 data points which sum to 40.

The average is the sum divided by the number of data points so 40/5 = 8, which is the same as the mean

The median is the middle number when the data is arranged numerically, so the median for this data set is 3
The example given is why the median is often used when distribution is extremely skewed, e.g. income distribution in the USA and UK.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 01, 2019, 10:18:17 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 30 May 2019

16 to 21 May Precipitation outweighs melt on these days, but not by much.
22 to 29 May Melt outweighs precipitation on these days.

30 -31 May Precipitation outweighs melt on this day, but not by much.

Next 10 days The GFS forecast still saying Greenland will be mostly dry, with even the SE looking extremely dry. Some moderate precipitation on the West coast.
_________________________________________________________
My prediction that belongs to me is that there will be more days of SMB loss but becoming much closer to the average daily SMB change. Given this reversion to far more average daily change, postings will be reduced to the weekly update of the accumulated SMB anomalies map.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 04, 2019, 03:53:58 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 3 June 2019

It is the day of the weekly update of the accumulated SMB anomalies map.

Melt now below average, but precipitation even more so. So daily SMB change being close to zero or a bit -ve. Shows clearly on the accumulated SMB graph.

The growth of SMB +ve anomalies in the SE in contrast with the growth of -ve anomalies over the rest of Greenland is shown in the attached gif of monthly changes (click to play).

The effect on Albedo in May is shown on the other gif.

Next 10 days The GFS forecast still saying Greenland will be fairly dry, with moderate precipitation in the north and north west especially.
_________________________________________________________
My prediction that belongs to me (that has been OK so far) is that there will be more days of SMB loss but becoming much closer to the average daily SMB change.

Given this reversion to far more average daily change, postings will be reduced to the weekly update of the accumulated SMB anomalies map.
Title: Re: Greenland 2019 Melt Season
Post by: oren on June 04, 2019, 05:25:30 PM
Thanks for your constant updates GRC. I think SMB max for the year can already be called at around May 20th, ~3 weeks earlier than usual. Let's hope for a benign melt season (and for GRACE data).
Title: Re: Greenland 2019 Melt Season
Post by: Darvince on June 08, 2019, 07:51:46 AM
Holy sh*t

(https://i.imgur.com/NfJopfB.png)

It's just as bad the D4 high, too, and the forecast trend has only gotten worse, and it's also on the Euro, as far as I can tell...
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 08, 2019, 11:16:56 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 7 June 2019

I picked up on the same theme as Darvince. An event on its way.

Recent Days
Melt now below average, but precipitation even more so. So daily SMB change being close to zero or a bit -ve. Shows clearly on the accumulated SMB graph.

Next 7 days
Precipitation
The GFS forecast still saying Greenland will be fairly  to very dry, with light precipitation in the west and a bit more in the SE. It is also likely that it will be a mix of rain and snow.

Melt and SMB change
Temperatures, especially in the long afternoons, are predicted to increase over the following days to a maximum on Thursday, when most of Greenland will be above zero. and to remain high (but not as high)  over a substantial area of Greenland in the following days.

The combination of ever increasing melt, together with low precipitation (some of which will fall as rain) suggest a major mass loss developing over the next week.
_________________________________________________________
My prediction that belonged to me (that has been OK so far) was that there will be more days of SMB loss but becoming much closer to the average daily SMB change.

That prediction looks likely to be another one for the rubbish tip.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on June 08, 2019, 06:26:55 PM

My prediction that belonged to me (that has been OK so far) was that there will be more days of SMB loss but becoming much closer to the average daily SMB change.

That prediction looks likely to be another one for the rubbish tip.

That prediction was spot on IMHO as there was a significant stall in SMB loss. The oncoming melt simply exemplifies the impact of short term weather.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 09, 2019, 11:21:35 AM

Melt and SMB change
Temperatures, especially in the long afternoons, are predicted to increase over the following days to a maximum on Thursday, when most of Greenland will be above zero. and to remain high (but not as high)  over a substantial area of Greenland in the following days.

The combination of ever increasing melt, together with low precipitation (some of which will fall as rain) suggest a major mass loss developing over the next week.

The melt event looks like being stronger, starting earlier and lasting longer.
____________________________________________________

Won't do the snow on Ellesmere Island, and the sea ice in Baffin Bay, the CAA and Hudson Bay a lot of good, either.
Title: Re: Greenland 2019 Melt Season
Post by: oren on June 09, 2019, 11:40:13 AM
Wow. That's some kind of event indeed.
Title: Re: Greenland 2019 Melt Season
Post by: ArcticMelt2 on June 09, 2019, 11:56:35 AM
This is very bad. A strong melting has already begun yesterday. The situation is aggravated by a cold winter (little snow). Expected a powerful flood, as in 2012.

It is interesting to know how soon the first data from GRACE-2 will appear.
Title: Re: Greenland 2019 Melt Season
Post by: Csnavywx on June 09, 2019, 02:17:08 PM
This is setting up to be an extreme event. Freezing levels on the FV3 and EC get very high (3000-4000m), possibly all the way to the summit. 700mb temps rise to +5 to +10C  for an extended period, meaning widespread intense surface melt and ponding. These temp values aloft are very similar to an unmodified subtropical airmass (500mb temps approaching -10C).
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on June 09, 2019, 05:33:51 PM
Slow, but constant snow melt at Freya Gletscher, T = +0.4°C
No additional melt ponds so far.
https://www.foto-webcam.eu/webcam/freya1/
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 11, 2019, 08:55:23 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 10 June 2019

It is the day of the weekly update of the accumulated SMB anomalies map.

Melt now below average, but precipitation even more so. So daily SMB change being below zero and lower than average. This difference is increasing and shows clearly on the accumulated SMB graph.

The SMB +ve anomalies in the SE in contrast with the growth of -ve anomalies over the rest of Greenland is increasing.

Next 10 days
Melt A melting event is commencing as much of Greenland becomes above freezing on Wednesday and Thursday. After that the event moderates somewhat but temperatures remain above average.

Precipitation The GFS forecast still saying Greenland will be fairly dry.
_________________________________________________________
My prediction that belongs to me (that to my surprise has been OK so far) is that there will be days of well above average melt and SMB loss, peaking on Wednesday or Thursday and moderating somewhat afterwards.
Title: Re: Greenland 2019 Melt Season
Post by: Greenbelt on June 11, 2019, 06:56:40 PM
Noticed prediction for very warm temps across most of Greenland this week.  Jet stream his highly N-S and very wavy across N America today.
(https://www.tropicaltidbits.com/analysis/models/gfs/2019061112/gfs_T2m_nhem_6.png)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 12, 2019, 09:23:28 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 11 June 2019

Melt was stronger but still below average, and it snowed in the SE. Hence SMB loss / gain about zero but ever increasing difference between the SE coastal fringe accumulated +ve SMB anomaly and the -ve anomaly for the rest of Greenland.
_________________________________________________________
[/b]My prediction that belongs to me (that to my surprise has been OK so far) is that there will be days of well above average melt and SMB loss, peaking on Wednesday or Thursday and moderating somewhat afterwards.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on June 12, 2019, 04:30:39 PM
Oh, boi.

This is Greenland west coast in the M8 band.

That darkening means melting.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 12, 2019, 06:41:47 PM
Oh, boi.

That darkening means melting.

http://nsidc.org/greenland-today/ have done a report on April & May 2019. Confirms what I have been wittering on about recently.

Note how their melt images and graphs tend to show a greater area and percentage of melt compared with DMI. Algorithms.....
Title: Re: Greenland 2019 Melt Season
Post by: Darvince on June 12, 2019, 11:02:22 PM
Oh, boi.

This is Greenland west coast in the M8 band.

That darkening means melting.

Very impressive... Over how many hours is this?
Title: Re: Greenland 2019 Melt Season
Post by: ArcticMelt2 on June 13, 2019, 03:41:48 AM
At the Summit +0.7 Celsius.
Title: Re: Greenland 2019 Melt Season
Post by: JayW on June 13, 2019, 04:25:12 AM
Oh, boi.

This is Greenland west coast in the M8 band.

That darkening means melting.

Very impressive... Over how many hours is this?
Looks like 24-36 hours.
You can watch here with timestamps. The eastern side is also impressive.

http://rammb-slider.cira.colostate.edu/?sat=jpss&z=3&im=36&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_m08&x=19660&y=14688.3330078125
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 13, 2019, 07:27:06 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 12 June 2019

Melt was much stronger and well above average, and it snowed in the SE. Hence SMB was a mass loss but not by much, but increasing again the difference between the SE coastal fringe accumulated +ve SMB anomaly and the -ve anomaly for the rest of Greenland.
_________________________________________________________
[/b]My prediction that belongs to me is now that today -Thursday - will see a strong melt and less snow in the SE, and in the days after melt moderating considerably, i.e. somewhat less of a major event than I thought a few days ago.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on June 13, 2019, 09:55:26 AM
Very impressive... Over how many hours is this?

Sorry, should have mentioned it.

It's roughly 2 days, but i skipped the still frames. So the last 4-5 frames where the darkening is expanding so dramatically is only ~ 4-5 hours.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on June 13, 2019, 01:19:41 PM
North Greenland. That glacier at Nares Land.

(Click to play)
Title: Re: Greenland 2019 Melt Season
Post by: JayW on June 13, 2019, 08:56:41 PM
 :o
Title: Re: Greenland 2019 Melt Season
Post by: oren on June 13, 2019, 09:03:19 PM
An event indeed!
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on June 13, 2019, 09:09:08 PM
I saw it was bad. I never imagined it to be that bad in the numbers.  :-[
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on June 13, 2019, 09:40:25 PM
No further melt ponds on Freya Gletscher today, but a faster snow melt than at all the other days before. And temperatures now above +10°C [guessing they do not represent the measurement standards as they are usual in weather stations].
Link: https://www.foto-webcam.eu/webcam/freya1/
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 13, 2019, 10:00:31 PM
Greenland very warm Thursday (today) Friday and Saturday. Stays above freezing on the coasts after that but not as extreme.

Max Temps attached
Title: Re: Greenland 2019 Melt Season
Post by: Rod on June 14, 2019, 03:07:28 AM
I hate to sound too dramatic, but this event is pretty damn dramatic for this early in the year, Greenland is on 🔥 (Worldview Bands 3-6-7).
Title: Re: Greenland 2019 Melt Season
Post by: werther on June 14, 2019, 04:50:13 AM
Just saw the Greenland temp spike on the graphs page...very worrying indeed!
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on June 14, 2019, 07:55:58 AM
It keeps going... obviously, given the temps.

This is a GIF showing M8 band overlayed with 'natural colours'.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 14, 2019, 08:34:47 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 13 June 2019

Melt was much stronger and well above average, another maximum for the year. Precipitation was minimal. Hence SMB had a very large mass loss  increasing again the -ve SMB anomaly for Greenland.
_________________________________________________________
[/b]My prediction that belongs to me is now from today -Friday - until Sunday will see a strong melt and little snow, and in the days after melt likely to moderate considerably.
Title: Re: Greenland 2019 Melt Season
Post by: Rod on June 14, 2019, 06:51:11 PM
The early melt action this week is very interesting as 2019 attempts to keep pace with 2012.  However, the longer term context is even more important. 

A new paper was published yesterday by Dr. Ruth Mottram from the Danish Meteorological Institute tracking three decades of observational data regarding the loss of ice sheet mass and how it compares to modeled projections.

Quote
Observations show surface lowering across virtually all regions of the ice sheet and at some locations up to −2.65 m year −1 between 1995 and 2017 based on radar altimetry analysis. In addition, calving fronts at 28 study sites, representing a sample of typical glaciers, have retreated all around Greenland since the 1990s and in only two out of 28 study locations have they remained stable. During the same period, two of five floating ice shelves have collapsed while the locations of grounding lines at the remaining three floating ice shelves have remained stable over the observation period. In a detailed case study with a fracture model at Petermann glacier, we demonstrate the potential sensitivity of these floating ice shelves to future warming. GRACE gravimetrically-derived mass balance (GMB) data shows that overall Greenland has lost 255 ± 15 Gt year −1 of ice over the period 2003 to 2016, consistent with that shown by IMBIE and a marked increase compared to a rate of loss of 83 ± 63 Gt year −1 in the 1993–2003 period.     

The rapid increase in the annual loss of ice during the period 2003 to 2016 compared to the period 1993 to 2003 is particularly troubling. 

Paper is open access at the link below:

https://www.mdpi.com/2072-4292/11/12/1407/htm

 
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on June 14, 2019, 07:33:21 PM

The rapid increase in the annual loss of ice during the period 2003 to 2016 compared to the period 1993 to 2003 is particularly troubling. 

This is equivalent to a tripling of the loss rate. If it tripled again in the next period (up to 2030) the mass loss would end at around 750-800 Gt year-1 (equivalent to around 2 mm year-1 global sea level rise only from Grønland).
Title: Re: Greenland 2019 Melt Season
Post by: Rod on June 15, 2019, 02:15:31 AM
Good article about the recent ice loss in Greenland.  Zack and Rick Thoman are both quoted in it.  It also features the photo Jim and FOW posted on here earlier. 

https://www.washingtonpost.com/weather/2019/06/14/arctic-ocean-greenland-ice-sheet-have-seen-record-june-ice-loss/
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 15, 2019, 11:51:35 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 14 June 2019

Melt was stronger and very much above average, another maximum for the year. Precipitation was low. Hence SMB had a large mass loss  increasing again the -ve SMB anomaly for Greenland.

[/b]My prediction that belongs to me is now from today -Friday - until Sunday or maybe even Tuesday will see a strong melt , and in the days after melt likely to moderate but perhaps still above average..

Precipitation is looking very dry over most of Greenland with perhaps moderate precipitation in the NorthWest (opposite corner to usual).

Strong SMB mass loss to continue?
_____________________________________________________

Click on melt image to activate gif - only goes round 5 times (slowly)
Title: Re: Greenland 2019 Melt Season
Post by: grixm on June 15, 2019, 12:17:30 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 14 June 2019
...

I have a noob question, why does that accumulated SMB graph show that over the course of a year, the total mass typically increases, even in the record 2012 season? That seems to contradict for example this graph from NASA that shows that every year the net balance is a mass decrease: https://climate.nasa.gov/vital-signs/ice-sheets/
Title: Re: Greenland 2019 Melt Season
Post by: BenB on June 15, 2019, 12:43:26 PM
I believe that basically the total mass balance for Greenland comes from surface accumulation/runoff (surface mass balance), basal melting, and ice discharge through calving.

Surface mass balance is (almost?) always positive, but in recent decades it has been much less positive, and has been massively outweighed by the negative mass balance from the other effects.
Title: Re: Greenland 2019 Melt Season
Post by: oren on June 15, 2019, 12:46:00 PM
In general: Surface Mass Balance includes precipitation (snow amd rain) added, minus sublimation and melt runoff.
But it does not include the flow of ice into the sea, mostly in the form of calving of icebergs.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 15, 2019, 01:34:15 PM
First paragraph from http://polarportal.dk/en/greenland/surface-conditions/

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

which is why I usually add a link to my posts.
Title: Re: Greenland 2019 Melt Season
Post by: grixm on June 15, 2019, 01:51:02 PM
I see, thanks for the info
Title: Re: Greenland 2019 Melt Season
Post by: Thomas Barlow on June 15, 2019, 02:36:02 PM
"Greenland lost 2 billion tons of ice yesterday, which is very unusual"
 - CNN
https://edition.cnn.com/2019/06/14/us/greenland-sudden-ice-melt-wxc/index.html?fbclid=IwAR3m_QoBi3-oSOYbilFUvVwChFER9C5EH586lUEJmBDKoCPMMBHrzPMtODQ
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on June 15, 2019, 02:55:29 PM
I'm quite surprised CNN would cover that! Good on them i guess.
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on June 15, 2019, 03:02:49 PM
"Greenland lost 2 billion tons of ice yesterday, which is very unusual"
 - CNN
https://edition.cnn.com/2019/06/14/us/greenland-sudden-ice-melt-wxc/index.html

FIFY :)

Thomas, when you share a link, could you please delete the Facebook spy part (which is everything after the real link including the question mark i.e. ?fbclid=IwAR3m_QoBi3-oSOYbilFUvVwChFER9C5EH586lUEJmBDKoCPMMBHrzPMtODQ)?

Everyone clicking this link will be tracked by Facebook even if they don't have an account.
Title: Re: Greenland 2019 Melt Season
Post by: jai mitchell on June 15, 2019, 03:32:13 PM
Dr. Jason Box from 2 weeks ago predicting the melt we just saw and its implications for the rest of the season.

https://www.youtube.com/watch?v=br9N_Cqmfz0
Title: Re: Greenland 2019 Melt Season
Post by: grixm on June 15, 2019, 06:46:27 PM
New melt ponds are appearing in the Freya Glacier webcam: https://www.foto-webcam.eu/webcam/freya1/

Title: Re: Greenland 2019 Melt Season
Post by: Tom_Mazanec on June 15, 2019, 08:48:27 PM
Greenland loses 2,000,000,000 tons of ice in a day:
https://edition.cnn.com/2019/06/14/us/greenland-sudden-ice-melt-wxc/index.html
Title: Re: Greenland 2019 Melt Season
Post by: Thomas Barlow on June 16, 2019, 01:54:39 AM
"Greenland lost 2 billion tons of ice yesterday, which is very unusual"
 - CNN
https://edition.cnn.com/2019/06/14/us/greenland-sudden-ice-melt-wxc/index.html

FIFY :)

Thomas, when you share a link, could you please delete the Facebook spy part (which is everything after the real link including the question mark i.e. ?fbclid=IwAR3m_QoBi3-oSOYbilFUvVwChFER9C5EH586lUEJmBDKoCPMMBHrzPMtODQ)?

Everyone clicking this link will be tracked by Facebook even if they don't have an account.

 ;D
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 16, 2019, 09:35:04 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 15 June 2019

Melt was stronger and very much above average, another maximum for the year. Precipitation was low but not that low. Hence SMB had a largish mass loss  increasing again the -ve SMB anomaly for Greenland.

[/b]My prediction that belongs to me is now from today - Sunday - until Tuesday will see a strong melt , and in the days after melt likely to moderate but perhaps still above average..

Precipitation is looking very dry over most of Greenland with perhaps moderate precipitation in the NorthWest (opposite corner to usual).

Strong SMB mass loss to continue but at a lower rate?
_____________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on June 16, 2019, 09:32:52 PM
Looks like another huge melt event just happened.

The whole southern half of Greenland that is.

GIF showing 16.04. ~10:00h to 16:00h UTC
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 17, 2019, 08:02:54 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 16 June 2019

Melt was stronger and very much above average, another maximum for the year. Precipitation was low. Hence SMB had a large mass loss increasing again the -ve SMB anomaly for Greenland.

[/b]My prediction that belongs to me is that today and Tuesday will see a strong melt, and in the days after melt likely to moderate but perhaps still above average..

Precipitation in the next week is looking very dry over most of Greenland apart from moderate precipitation in the NorthWest.

SMB mass loss to continue but at a lower rate?
_____________________________________________________
Note from DMI

When comparing with the surface mass balance under ”Daily change”, that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on June 17, 2019, 06:53:24 PM
The accelerated Grønland melt was also a topic on wetteronline.de, one of the most famous weather websites in Germany.
https://www.wetteronline.de/klimawandel/arktis-erwaermt-sich-rasant-rekord-eisschmelze-auf-groenland-2019-06-17-gr
Unfortunately the melt area graph was plotted without an y-axis, so that only a relative comparison between 2019, 2016, 2012 and 2007 is possible.

(edit: See also the discussion in the "multimeter sea level rise" thread in the Antarctica section of tis forum)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 18, 2019, 07:42:53 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 17 June 2019

Melt was stronger and very much above average, near the maximum for the year. Precipitation was very low. Hence daily SMB had a very large mass loss increasing again the cumulative -ve SMB anomaly for Greenland.

The weekly update of accumulated SMB is out today. It shows the mass loss anomaly over the entirety of Greenland apart from a narrow coastal fringe in the SE.

a[/b]My prediction that belongs to me is that Tuesday and perhaps Wednesday will see a strong melt, and in the days after melt likely to moderate but perhaps still above average..
 
Precipitation in the next week is looking dry over most of Greenland apart from moderate precipitation in the NorthWest.

SMB mass loss to continue but at a lower rate?
_____________________________________________________
Note from DMI

When comparing with the surface mass balance under ”Daily change”, that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on June 18, 2019, 02:50:53 PM
What accounts for the surface mass increases along the western edge of the ice sheet? It can’t be from excess snow because we would see the anomaly extend inland. Could this be capturing the slide of the ice sheet towards the sea.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 18, 2019, 03:17:16 PM
What accounts for the surface mass increases along the western edge of the ice sheet? It can’t be from excess snow because we would see the anomaly extend inland. Could this be capturing the slide of the ice sheet towards the sea.
Not a clue. You could try asking DMI - including the guy who did that video about probabilities of a major melt this season.

It has been there a long time.(See attached map )
Title: Re: Greenland 2019 Melt Season
Post by: FishOutofWater on June 18, 2019, 10:54:27 PM
I'm pretty sure you are right about the blue streaks in the sea of red on the west side of Greenland. They look like areas where glaciers advanced seawards in the freezing season and built up mass at low elevation.

Clearly there was heavy snowfall on the southeast coast and dry weather on the west side. These easterly winds advected warm Atlantic waters towards the tip of Greenland, enhancing the Atlantic meridional overturning circulation.

The enhanced AMOC is one reason Greenland melting has picked up this year.
Title: Re: Greenland 2019 Melt Season
Post by: KiwiGriff on June 19, 2019, 12:12:55 AM
Quote
What accounts for the surface mass increases along the western edge of the ice sheet? It can’t be from excess snow because we would see the anomaly extend inland. Could this be capturing the slide of the ice sheet towards the sea.
I expect it is due to the steeply rising elevation with any snow fall accruing on the the seaward edge of the ice sheet .
Once the air reaches the tops or downward side snow no longer participates out to the same extent  .
We get the same effect here in NZ with horrendous rain fall totals  along the south western coast of the south island not necessarily translating into high snow fall further  inland in the alps.
Compare Milford sounds rainfall .
https://figure.nz/chart/5IuPMt4ZwD9Sdkf7-vonLRXKT3zJQihCK
With Manapouri a little inland.
https://figure.nz/chart/5IuPMt4ZwD9Sdkf7-WMtvnjdF21QWuJnN


I am no expert someone more qualified may have a better idea.

 
Title: Re: Greenland 2019 Melt Season
Post by: Darvince on June 19, 2019, 05:35:07 AM
The high elevation immediately on the coast of southeast Greenland as well as anomalous circulation for the past few years driving low after low into that region of the coast are the reason for the strong positive surface mass balance anomaly being in that region, as well as its limited extent to just that region.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 19, 2019, 10:06:17 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 18 June 2019

Melt was strong and very much above average, near the maximum for the year. Precipitation was very low. Hence daily SMB had a very large mass loss increasing again the cumulative -ve SMB anomaly for Greenland.

My prediction that belongs to me is that today (Wednesday) will see a strong melt, and in the days after melt likely to moderate but perhaps still above average..
 
Precipitation in the next week is looking dry over most of Greenland apart from moderate precipitation in the NorthWest.

SMB mass loss to continue but at a lower rate?
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
Title: Re: Greenland 2019 Melt Season
Post by: johnm33 on June 19, 2019, 01:15:15 PM
What accounts for the surface mass increases along the western edge of the ice sheet? It can’t be from excess snow because we would see the anomaly extend inland. Could this be capturing the slide of the ice sheet towards the sea.
My guess would be winds dropping their moisture content on the eastern side without loosing energy, then becoming warm foehn winds as they drop down the ice sheet warming more and more as they drop causing melt and run off down the slopes.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 20, 2019, 08:15:00 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 19 June 2019

Melt was strong and very much above average, near the maximum for the year. Precipitation was low in most of Greenland except for in the North West, which was enough to reduce daily SMB mass loss to average.

My prediction that belongs to me is that melt, in the days ahead is likely to moderate but perhaps still stay above average..
 
Precipitation in the next week is looking like moderate precipitation in the NorthWest becoming more general across Greenland. If GFS is to be believed, it is possible that a river of rain starting in Western Siberia will cross the entire Arctic, arriving at the northern tip of Greenland in about one weeks time.

SMB mass loss to continue but at a lower rate?
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 21, 2019, 03:56:37 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 20 June 2019

A bit to my surprise melt was even a bit stronger and very much above average, near the maximum for the year. Precipitation was again low in most of Greenland except for in the North West, which was enough to reduce daily SMB mass loss to average. Below average Albedo expanding to higher elevations in the interior.

My prediction that belongs to me is that melt, Friday to Sunday ahead is likely to moderate but perhaps still stay above average.. But perhaps from Monday onwards higher melt gain, even reaching the very far north?
 
Precipitation in the next week is looking like moderate precipitation in the NorthWest becoming more general across Greenland. At least on the fringes (i.e. at low altitude) some of this will fall as rain.

SMB mass loss to continue but at a more average rate?
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 22, 2019, 03:04:17 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 20 June 2019

Surprised again that melt was even a bit stronger and very much above average, near the maximum for the year. Precipitation was again low in most of Greenland except for in the North West, which was enough to reduce daily SMB mass loss to average.

My prediction that belongs to me is that melt, today and Sunday ahead is likely to moderate but perhaps still stay above average.. But perhaps from Monday onwards higher melt gain, even reaching the very far north?
 
Precipitation in the next week is looking like moderate precipitation in the NorthWest becoming more general across Western Greenland. At least on the fringes (i.e. at low altitude) some of this is likely to fall as rain.

SMB mass loss to continue but at a more average rate? Will this mean the 2019 crosses the 2012 red line in the next week?
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 23, 2019, 09:34:10 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 22 June 2019

Surprised yet again that melt was even a bit stronger and very much above average, near the maximum for the year. Precipitation was again low in most of Greenland except for in the central West coast, which was enough to reduce daily SMB mass loss to well below average.

My prediction that belongs to me is that melt, today (Sunday) will be strong and is likely to moderate afterwards but perhaps still stay above average.. But just maybe  higher melt gain, even spreading further over the very far north looking further ahead?
 
Precipitation in the next 7 days is looking like above average precipitation in the NorthWest becoming more general across Western and then Southern Greenland. At least on the fringes (i.e. at low altitude) some of this is likely to fall as rain. (last image)

SMB mass loss to continue but at a more average rate or even reverse? It is now looking likely  the SMB graph will show the 2019 line crossing the 2012 red line in about a week.

It makes me speculate that in 2012 lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 25, 2019, 10:18:36 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 24 June 2019

Weekly map of SMB anomaly attached.

Melt remains strong and very much above average, near the maximum for the year. Precipitation happened in much of Greenland which was enough to reverse daily SMB mass loss to mass gain.

See next post for images
Precipitation in the next 7 days is looking like above average precipitation in the NorthWest becoming more general across Western and then Southern Greenland. At least on the fringes (i.e. at low altitude) some of this is likely to fall as rain. (see next post for images).
Melt. Temperatures above freezing around most of the coast in the next week, with warmth arriving into the far North by Friday. Perhaps melt above average but to not such an extent.

SMB mass loss to continue to reverse into mass gain? It is now looking likely  the SMB graph will show the 2019 line crossing the 2012 red line in a day or two.

It becomes clear that precipitation, or the lack of it may determine the overall SMB loss during the melting season at least as much as melt. My speculation is that in 2012 lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 25, 2019, 10:28:20 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 24 June 2019 (contd)

Albedo anomaly map attached. A tale of two halves. The South - Albedo below average, the North -above average.

Temperature map for Friday afternoon shows warmth over much of Northern Greenland.
Also note the extreme warmth over Baffin Island and the CAA.

Precipitation looks above average over most of Greenland (except perhaps in the East). Contrast that with very dry conditions over the CAA and Baffin Bay.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 26, 2019, 09:20:49 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 25 June 2019

Melt remains strong and very much above average, near the maximum for the year. The persistence of this strong melt is unusual?
Precipitation was enough to reverse daily SMB mass loss to zero.

GFS has changed the [/i]Precipitation outlook for the next 7 days. Now looking  much dryer. At least on the fringes (i.e. at low altitude) some precipitation is likely to fall as rain.

Melt. Temperatures above freezing around most of the coast in the next week, with warmth arriving into the far North by Friday. Perhaps melt above average to very much above average.

SMB mass loss to continue to reverse into mass gain? It is now looking likely  the SMB graph will show the 2019 line crossing the 2012 red line in a day or two.

It becomes clear that precipitation, or the lack of it may determine the overall SMB loss during the melting season at least as much as melt. My speculation is that in 2012 lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 27, 2019, 09:53:46 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 26 June 2019

Melt remains strong and even stronger, very much above average, near the maximum for the year. The persistence of this strong melt is unusual? GIF attached shows history since June 10 (wobbles a bit - not a clue why). Click to start, runs 5 times and then stops.

Precipitation was not enough to reverse daily SMB mass loss to zero, but mass loss less than average.

GFS has changed the [/i]Precipitation outlook for the next 7 days. Now looking  like very dr y in the NW, much wetter in the SE (a more normal pattern). At least on the fringes (i.e. at low altitude) some precipitation is likely to fall as rain.

Melt. Temperatures above freezing around most of the coast in the next week, with considerable warmth arriving into the far North by Friday. Perhaps melt above average to very much above average.

SMB mass loss to continue to reverse into mass gain or reduced mass loss? It is now looking likely the SMB graph will show the 2019 line crossing the 2012 red line in a day or two.

It becomes clear that precipitation, or the lack of it may determine the overall SMB loss during the melting season at least as much as melt. My speculation is that in 2012 lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
Title: Re: Greenland 2019 Melt Season
Post by: be cause on June 27, 2019, 11:44:20 AM
Headline in this week's Economist .. 'climate change' .. ' Greenland is melting ' .. a very informative piece .. from Eric the red to the 7 metres sea level rise locked in the ice sheet . Talks of NAO , warming , jet stream etc and concludes with Jason Box of the Geological Survey of Denmark predicting a 1mm extra sea-level rise this year in consequence ..

  the way the forecast is heading that could be 2mm (sic) .. b.c.

   
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 28, 2019, 10:01:57 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 27 June 2019

Melt remains strong and even stronger, the maximum for the year. Agian very much on the Western coast. The persistence of this strong melt is unusual?

Precipitation was not enough to reverse daily SMB mass loss to zero, but mass loss less than average. Mostly in the NW and W.

GFS [/i]Precipitation outlook for the next 7 days now looking  like very dry in the NW, much wetter in the SE (a more normal pattern). At least on the fringes (i.e. at low altitude) some precipitation is likely to fall as rain.

Melt. Temperatures above freezing around most of the coast in the next week, with considerable warmth arriving into the far North by Friday. Perhaps melt above average to very much above average. Note the SST anomalies in Baffin Bay.

SMB mass loss to continue to reverse into mass gain or reduced mass loss? It is now looking likely the SMB graph will show the 2019 line crossing the 2012 red line in a day or two.

It becomes clear that precipitation, or the lack of it may determine the overall SMB loss during the melting season at least as much as melt. My speculation is that in 2012 lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Alexander555 on June 28, 2019, 09:12:25 PM
Would it be wrong to think that we are going to see an acceleration of SMB loss in the next years ? In the years when there is less precipitation, the melt extent is probably not going to get smaller.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 28, 2019, 09:41:33 PM
Would it be wrong to think that we are going to see an acceleration of SMB loss in the next years ? In the years when there is less precipitation, the melt extent is probably not going to get smaller.
What you say is correct, but will it happen that way?
An attempt at an answer just gives some +ves and -ves, as usual.

Greenland will get warmer, so more melt. SMB goes down.
But will this mean more warmer wetter air falling as snow on higher elevations. SMB goes up.
But will rain at lower elevations compromise glaciers so calving increases ? Not much change to Surface Mass Balance (SMB) but Greenland loses mass and loads more ice into the ocean so sea level rises more quickly.

AbruptSLR posted an abstract about what might have happened a few k years ago.

Quote
Our results indicate that Holocene warming coincided with elevated precipitation, without which modeled retreat in the Kangerlussuaq region is more rapid than suggested by observations. Less conclusive is if high temperatures during the HTM were specifically associated with a transient increase in precipitation, as the results depend on the assumed temperature history. The importance of precipitation in controlling ice sheet extent during the Holocene underscores the importance of Arctic sea ice loss and changing precipitation patterns on the future stability of the GrIS.
https://forum.arctic-sea-ice.net/index.php/topic,2205.msg208330.html#msg208330

i.e. as usual more questions than answers.
Title: Re: Greenland 2019 Melt Season
Post by: Alexander555 on June 28, 2019, 10:16:11 PM
Probably more questions than answers. But i would'nt be surprised if we already get a good indication on this one in a relative short periode of time. We will see.
Title: Re: Greenland 2019 Melt Season
Post by: oren on June 28, 2019, 11:10:45 PM
GRACE data will be the judge, when it resumes at last.
Title: Re: Greenland 2019 Melt Season
Post by: Rod on June 29, 2019, 01:41:38 AM
Dr. MacFerrin posted a couple of informative tweets on this topic today.  @IceSheetMike

Below is the link to the paper he attached:

https://www.nature.com/articles/s41467-018-05002-0

Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 29, 2019, 09:59:59 AM
Dr. MacFerrin posted a couple of informative tweets on this topic today.  @IceSheetMike

Below is the link to the paper he attached:

https://www.nature.com/articles/s41467-018-05002-0
Thanks for the link
I did not realise the deniers had picked up on SMB. Silly me.

I used to add this quote from DMI to every post on this thread :-
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.

Unfortunately, on the old site from DMI it also used to say that the calving exceeded surface mass gain by about 200 gigatons per year. Perhaps I need to add the note. I assume some of the denier scum look at this forum from time to time in search of ammunition.
_______________________________
By the way, GRACE-FO is producing data for scientists, but not a simple table of mass change. And they have chucked "ftp", so the tabulated data 2002 to early 2017 from the original GRACE project is no longer available from JPL. Going backwards, not forwards. Ho hum.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 29, 2019, 11:35:10 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 28 June 2019

Melt remains strong and even stronger yet again, the maximum for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, mainly in the East, was not enough to reverse daily SMB mass loss to zero, and mass loss was average.

Outlook - a tale of 2 halves, West and East.

GFS Precipitation outlook for the next 7 days now looking  like very dry to drought in the West coast and centre, much wetter all the way down the East coast. Much is coming all the way from a warm/hot western Siberia passing over the Atlantic edge of the Arctic sea ice. A bit of rain may come from the south to affect the southern tip of Greenland. GFS says at least on the fringes (i.e. at low altitude) some precipitation is likely to fall as rain.

Melt. Temperatures above freezing around most of the coast in the next week, with considerable warmth arriving into the far North by Friday. Perhaps melt above average to very much above average. The SST anomalies in Baffin Bay can only increase.

SMB mass change a matter of which will prevail, precipitation and melt. But it still looks likely the SMB graph will show the 2019 line continuing to cross the 2012 red line in a day or two.
And what is the prognosis for calving given all this melt and runoff ?

It becomes clear that precipitation, or the lack of it may determine the overall SMB loss during the melting season at least as much as melt. My speculation is that in 2012 lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me (to any denier creeps out there):
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas.
https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.

Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on June 29, 2019, 02:31:54 PM
gerontocrat...are the gray shaded areas 1 SD or 2 SD from the mean?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 29, 2019, 03:48:27 PM
gerontocrat...are the gray shaded areas 1 SD or 2 SD from the mean?

Neither.

Don't ask me why but  DMI  does this on the SMB graph and the melting graph..

"The light grey band shows differences from year to year. For any calendar day, the band shows the range over the 30 years (in the period 1981-2010), however with the lowest and highest values for each day omitted."

So the amazing stuff e.g. 2012 when nearly all of Greenland was melting for a couple of days - is not there.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on June 30, 2019, 11:49:38 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 29 June 2019

Almost a word for word repeat of yesterday's post because this event just will not stop.

Melt remains strong and even stronger yet again, the maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, mainly in the South East, was not strong, and mass loss was above average.

Outlook - a tale of 2 halves, West and East.

GFS Precipitation outlook for the next 7 days now looking  like very dry to drought in the West coast and centre, some precipitation all the way down the East coast. Much is coming all the way from a warm/hot western Siberia passing over the Atlantic edge of the Arctic sea ice. A bit of rain may come from the south to affect the southern tip of Greenland. GFS says at least on the fringes (i.e. at low altitude) some precipitation is likely to fall as rain.

Melt. Temperatures above freezing around most of the coast in the next week, with considerable warmth arriving into the far North. Perhaps melt above average to very much above average. The SST anomalies in Baffin Bay can only increase.

SMB mass change is a matter of which will prevail, precipitation and melt. But it still looks likely the SMB graph will show the 2019 line continuing to cross the 2012 red line in a day or two.
And what is the prognosis for calving given all this melt and runoff ? Not a lot of news about icebergs in Baffin Bay and iceberg alley to be found.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation is that in 2012 lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me (to any denier creeps out there):
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas.
https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
Title: Re: Greenland 2019 Melt Season
Post by: oren on June 30, 2019, 01:28:50 PM
gerontocrat...are the gray shaded areas 1 SD or 2 SD from the mean?

Neither.

Don't ask me why but  DMI  does this on the SMB graph and the melting graph..

"The light grey band shows differences from year to year. For any calendar day, the band shows the range over the 30 years (in the period 1981-2010), however with the lowest and highest values for each day omitted."

So the amazing stuff e.g. 2012 when nearly all of Greenland was melting for a couple of days - is not there.
In reality the shaded area is showing approximately 2SD.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on June 30, 2019, 02:50:09 PM
Thanks...both of you.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on June 30, 2019, 02:53:43 PM

Melt. Temperatures above freezing around most of the coast in the next week, with considerable warmth arriving into the far North. Perhaps melt above average to very much above average. The SST anomalies in Baffin Bay can only increase.

SMB mass change is a matter of which will prevail, precipitation and melt. But it still looks likely the SMB graph will show the 2019 line continuing to cross the 2012 red line in a day or two.
And what is the prognosis for calving given all this melt and runoff ? Not a lot of news about icebergs in Baffin Bay and iceberg alley to be found.


With such aggressive, widespread melt on southwest Greenland, shouldn't we be looking for basal and surface melt surges? I remember seeing a video from 2012 where roads and bridges were washed away by torrents of water.
Title: Re: Greenland 2019 Melt Season
Post by: Sebastian Jones on June 30, 2019, 05:42:33 PM
Thanks...both of you.
I want to take this opportunity to thank particularly the venerable ( meant respectfully) Gerontocrat and those that support his analyses- for not just keeping us informed on what is happening on Greenland almost in real time- but also for adding to our understanding of the processes involved. Thanks!
Title: Re: Greenland 2019 Melt Season
Post by: JayW on June 30, 2019, 11:24:51 PM
Winds descending down the western slope of Greenland appear to be promoting melt.
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=3&im=18&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_m08&x=20724.056640625&y=14521.5
Requires a click
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on June 30, 2019, 11:41:20 PM
I guess we will see this in the numbers tomorrow, that the fat melt hasn't stopped yet.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 01, 2019, 12:36:41 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 30 June 2019

Again almost a word for word repeat of yesterday's post because this event just will not stop.

Melt remains strong and even stronger yet again, the maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, mainly in the South East, was not strong, and mass loss was aroundaverage.

Outlook - a tale of 2 halves, West and East.

GFS Precipitation outlook for the next 7 days now looking  like very dry to drought in the West coast and centre, some precipitation all the way down the East coast. Much is coming all the way from a warm/hot western Siberia passing over the Atlantic edge of the Arctic sea ice. A bit of rain may come from the south to affect the southern tip of Greenland. GFS says at least on the fringes (i.e. at low altitude) some precipitation is likely to fall as rain.

Melt. Temperatures above freezing around most of the coast in the next week, with considerable warmth arriving into the far North. Perhaps melt above average to very much above average. The SST anomalies in Baffin Bay can only increase.

SMB mass change is a matter of which will prevail, precipitation and melt. But it still looks likely the SMB graph will show the 2019 line continuing to cross the 2012 red line in a day or two.
And what is the prognosis for calving given all this melt and runoff ? Not a lot of news about icebergs in Baffin Bay and iceberg alley to be found.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012 lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me (to any denier creeps out there):
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas.
https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.

WOBBLY GIF ATTACHED - click to start
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on July 01, 2019, 05:49:58 PM
From the Nares Strait thread:

Huge melt event in Kane Basin.

Looks like this in Sentinel.  :o
Title: Re: Greenland 2019 Melt Season
Post by: oren on July 01, 2019, 06:22:46 PM
This is not a melt event involving sea ice in Kane Basin itself. Rather, it's meltwater on the ice sheet, in the lower reaches of Petermann and Humboldt glaciers behind their respective calving fronts. It happens most years that I could find, and in 2012 covered a wider area, but this year it's much bluer. I never did notice it before that Sentinel image though.
Note: some years removed due to clouds. Click to animate.
Title: Re: Greenland 2019 Melt Season
Post by: Rod on July 02, 2019, 12:20:02 AM
Interesting article from NSIDC on the big melting event last month:

A record melt event in mid-June

http://nsidc.org/greenland-today/2019/07/a-record-melt-event-in-mid-june/

Title: Re: Greenland 2019 Melt Season
Post by: wallen on July 02, 2019, 02:52:40 AM
A viewing of the West side of Greenland on Worldview with corrective reflectance (7-2-1) The sheer volume of melt and I would image runoff is staggering.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 02, 2019, 01:11:52 PM
Interesting article from NSIDC on the big melting event last month:

A record melt event in mid-June

http://nsidc.org/greenland-today/2019/07/a-record-melt-event-in-mid-june/
What is going on over the last 21 days is a lot more than a headline catching spike. The melt just will not stop.
Title: Re: Greenland 2019 Melt Season
Post by: oren on July 02, 2019, 01:16:49 PM
Melt percent has been stubbornly staying at +2SD level for the last ~3 weeks. A very big event. I believe the persistence gives meltwater the chance to accumulate and flow, rather than refreeze in situ.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on July 02, 2019, 08:38:46 PM
Oren,
How did you determine that the grey zone that shows "all but the highest and lowest daily records of 1981-2010 data" (per Gerontocrat's June 29 post (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg209212.html#msg209212)) is approximately 2SD? Is there a 'rule of thumb' involved here?  You said it was so on June 30 (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg209473.html#msg209473).

There are 30 data points for each day, remove the largest and smallest; the resulting graph shows approximately how many standard deviations of the original set? 

To test this, I created a set of 30 random numbers between 20 and 40, which is approximately the range shown on the daily melt extent (%) chart at maximum melt in mid-July.  I then added a random number between -5.0 and +5.0 to each of the first set, so that I might have numbers larger an smaller than the 20 and 40.  With this new set of numbers, I identified 2SD, per Excel's formula [=2 * STDEV(set)].  Also obtained average, 2nd lowest [=SMALL(set,2)] and 2nd highest values.  I obtained multiple sets of data and averaged them.
Results: 
Average = 29.8
2SD = 13.5
Ave - 2SD = 16.3
Ave + 2SD = 43.3
2nd Lowest = 19.2
2nd Highest = 40.5

Interesting: not so terribly far off!  The range between +/- 2SD was 27 while the range between 2nd highest to 2nd lowest was only 21.3.
Title: Re: Greenland 2019 Melt Season
Post by: anaphylaxia on July 02, 2019, 09:36:37 PM
Oren,
How did you determine that the grey zone that shows "all but the highest and lowest daily records of 1981-2010 data" (per Gerontocrat's June 29 post (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg209212.html#msg209212)) is approximately 2SD? Is there a 'rule of thumb' involved here?  You said it was so on June 30 (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg209473.html#msg209473).
...
I think the trick is with the mathematical properties of normal distribution, and the number of years available for observation. A 2-3 sigma event represents 4.2 % of all in a normal distribution, and there are ~40 years of data available, thus discarding one maxima and minima gets rid of the 5 % of the observations, corresponding to roughly the probability of them occuring.
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on July 02, 2019, 10:09:15 PM
Gerontocrat,
is it possible to add to the melt percentage chart the melt percentage of 2012 with an extra line to see how good 2019 catches up with the record-breaking year?
Thanks in advance.
Title: Re: Greenland 2019 Melt Season
Post by: oren on July 02, 2019, 11:11:31 PM
Oren,
How did you determine that the grey zone that shows "all but the highest and lowest daily records of 1981-2010 data" (per Gerontocrat's June 29 post (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg209212.html#msg209212)) is approximately 2SD? Is there a 'rule of thumb' involved here?  You said it was so on June 30 (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg209473.html#msg209473).
...
I think the trick is with the mathematical properties of normal distribution, and the number of years available for observation. A 2-3 sigma event represents 4.2 % of all in a normal distribution, and there are ~40 years of data available, thus discarding one maxima and minima gets rid of the 5 % of the observations, corresponding to roughly the probability of them occuring.
Indeed. The probability of random values to fall within a distance of +-2SD around the mean in a normal distribution is 95%. 28/30 of the ("random") observations for each day is ~94% of all the values. so the shaded area is approximately +-2SD.
Title: Re: Greenland 2019 Melt Season
Post by: lifeblack on July 03, 2019, 12:29:05 AM

There are 30 data points for each day, remove the largest and smallest; the resulting graph shows approximately how many standard deviations of the original set? 

To test this, I created a set of 30 random numbers between 20 and 40, [...]  With this new set of numbers, I identified 2SD, per Excel's formula [=2 * STDEV(set)]. 

Just to keep things mathematically clear, 'random' does not generally create a normal (gaussian) distribution (bell-curve), and the  68-95-99.7 magical property of standard deviation is only true for gaussian distributions.

Having said that though, it still sounds like a reasonable approximation
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on July 03, 2019, 01:10:44 AM
Although I asked the question - and thanks for the several responses - I went out to discern if I could 'rationalize' Oren's 'rule of thumb' and feel I successfully supported it empirically.  Yes my data wasn't anything near normal, but I wonder how 'normal' Greenland's data is!

Thanks all!

I'll add a postscript.  My 1st year Physics university lecturer was from Ireland.  (The day after a helicopter was hijacked and used to help an IRA member in a British prison escape, we discussed the event in class.)  Anyway, this man had learned in secondary school, he said, all sorts of mathematical/arithmetic shortcuts, such as Pi2~=10.  He could do the arithmetic associated with an 'all the blanks filled' formula as fast in his head to 1 significant digit (but correct order of magnitude) as I could punch the numbers into my HP35 pocket calculator, only I sometimes made keyboard mistakes.  (The HP's reverse-Polish system made this type of calculations very easy.)  My sense is that a European science and math education in high school is often 'richer' than an American one.
Title: Re: Greenland 2019 Melt Season
Post by: oren on July 03, 2019, 02:30:15 AM
Just to keep things mathematically clear, 'random' does not generally create a normal (gaussian) distribution (bell-curve), and the  68-95-99.7 magical property of standard deviation is only true for gaussian distributions.

Having said that though, it still sounds like a reasonable approximation
You are correct lifeblack, I've used the "random" term flexibly.
To my defense, although my B.Sc was in both physics and math, I have always and forever identified as a (hobby) physicist, never as a mathematician.
Title: Re: Greenland 2019 Melt Season
Post by: Phil. on July 03, 2019, 04:22:04 AM
Although I asked the question - and thanks for the several responses - I went out to discern if I could 'rationalize' Oren's 'rule of thumb' and feel I successfully supported it empirically.  Yes my data wasn't anything near normal, but I wonder how 'normal' Greenland's data is!

Thanks all!

I'll add a postscript.  My 1st year Physics university lecturer was from Ireland.  (The day after a helicopter was hijacked and used to help an IRA member in a British prison escape, we discussed the event in class.)  Anyway, this man had learned in secondary school, he said, all sorts of mathematical/arithmetic shortcuts, such as Pi2~=10.  He could do the arithmetic associated with an 'all the blanks filled' formula as fast in his head to 1 significant digit (but correct order of magnitude) as I could punch the numbers into my HP35 pocket calculator, only I sometimes made keyboard mistakes.  (The HP's reverse-Polish system made this type of calculations very easy.)  My sense is that a European science and math education in high school is often 'richer' than an American one.
Yes, we learned all sorts of tricks back then in the absence of calculators out of necessity.  I still use the pi^2 trick, p1=22/7 etc.  One thing we learned was how to make approximations to speed up mental calculations, I still get remarks from students when I give my answer while they're still entering data.  :) Once while building some research equipment we needed to make an adjustment to the spacing to give a rotation of 30º.  I looked at it and told the tech that we'd need a 0.012" shim, they looked at me in astonishment and said there's no way you can know that!  They went and got the calculator and it turned out we needed 0.0115", they repeated the calculation a few times in disbelief.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on July 03, 2019, 05:03:52 AM
I like pi ~=113 into 355 or "113355" with a manual divide calculation structure put in the middle:

      __3.141592... (and then it goes off)
113/355


A couple years after I was in that Physics class, I was in my roommate's side of the room.  We were figuring out how much cash we needed to take to the post office, and we figured out we needed to mail 20 letters and postage was 13 cents then.  I ran over to my side of the room to get my calculator and he said "$2.60" and I said "How do you know?" as I knew he didn't own a calculator...  Some lessons we (I) don't learn quickly!
Title: Re: Greenland 2019 Melt Season
Post by: sidd on July 03, 2019, 06:50:45 AM
sin(30 degrees) = 1/2 is one i use a lot

perhaps we need a thread called quick math trix

sidd
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 03, 2019, 10:56:05 AM
Gerontocrat,
is it possible to add to the melt percentage chart the melt percentage of 2012 with an extra line to see how good 2019 catches up with the record-breaking year?
Thanks in advance.
Nope. No can do. The graph is straight from DMI's polar portal website. I don't download data on Greenland - a bridge too far for me.

NSIDC's Greenland Today (http://nsidc.org/greenland-today/) has an interactive chart thingy
https://nsidc.org/greenland-today/greenland-surface-melt-extent-interactive-chart/

Note that I am not posting data from there. Why? They do use the same definitions for melt and SMB changes. But they use a different model (I think) with coarser resolution. e.g. The DMI melt graph does not show the same huge spike on Jun 10 -11.

I don't want to mix apples and pears, and DMI does the daily SMB balance data. So it is DMI for me.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 03, 2019, 11:09:15 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 30 June 2019

Again almost a word for word repeat of previous days' posts because this event just will not stop.

Melt remains strong and even stronger yet again, the maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, mainly in the South East, was not strong, and mass loss was around average.

Outlook - a tale of the South-East and the rest.

GFS Precipitation outlook for the next 7 days now looking  like very dry to drought over most of Greenland apart from the SE. i.e. back to normal. GFS says at least on the fringes (i.e. at low altitude) any precipitation is likely to fall as rain.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed..

SMB mass change is a matter of which will prevail, precipitation and melt. But it still looks likely the SMB graph will show the 2019 line continuing to cross the 2012 red line in a day or two.
And what is the prognosis for calving given all this melt and runoff ? Not a lot of news about icebergs in Baffin Bay and iceberg alley to be found.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high,  lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
Title: Re: Greenland 2019 Melt Season
Post by: BenB on July 03, 2019, 11:35:53 AM
Gerontocrat, I have a quick question. You've said in your recent posts that melt was strong, as confirmed by the graph, and that precipitation was not strong, resulting in around average mass loss. Presumably the precipitation, albeit not strong in absolute terms, was significantly above average, otherwise it wouldn't offset the strong melt. Or am I missing something?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 03, 2019, 12:09:16 PM
Gerontocrat, I have a quick question. You've said in your recent posts that melt was strong, as confirmed by the graph, and that precipitation was not strong, resulting in around average mass loss. Presumably the precipitation, albeit not strong in absolute terms, was significantly above average, otherwise it wouldn't offset the strong melt. Or am I missing something?
After having a look and a think I think you are right, and to add to that while melt looks to be right up there at perhaps +2SD, what looks like a small amount of precipitation can reduce the SMB loss to average.

Another piece of evidence to suggest that maybe variation in precipitation is more important than melt. Maybe one day I will try and extract the precipitation data if it is on the DMI portal., especially to see if 2012 was really dry.
Title: Re: Greenland 2019 Melt Season
Post by: BenB on July 03, 2019, 12:33:52 PM
Thanks, Gerontocrat. I have a follow-up question to you and others:

Even if a relatively small amount of precipitation may offset above-average melting in the daily SMB, is this actually good for the ice in the medium/long term? Or does the fact that anomalous precipitation is also presumably falling as rain at lower altitudes contribute to destabilisation/lubrication of glaciers, potentially increasing rates of glacier flow and the amount of calving?
Title: Re: Greenland 2019 Melt Season
Post by: oren on July 03, 2019, 12:42:01 PM
A high melt rate, especially if sustained throughout the season, will certainly contribute to glacier speedup and increased calving. This is what happened in 2012 and afterwards, for example in Jakobshavn.
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on July 03, 2019, 12:52:33 PM
A high melt rate, especially if sustained throughout the season, will certainly contribute to glacier speedup and increased calving. This is what happened in 2012 and afterwards, for example in Jakobshavn.

I wonder what will be the extend of the Greenland cold blob come wnd of this season and how will next year's weather will be affected
Title: Re: Greenland 2019 Melt Season
Post by: BenB on July 03, 2019, 12:53:42 PM
I understand that, Oren, but I was wondering specifically whether there is a difference between a high melt rate combined with anomalously high precipitation (what we are seeing this year), and a year with high melt but without the precipitation, e.g. 2012, presumably, judging by the strongly negative net SMB. Or did 2012 also have relatively high precipitation at low altitude, but little/none falling as snow? That seems unlikely, on the face of it, but I don't entirely rule it out.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 03, 2019, 02:26:21 PM
Thanks, Gerontocrat. I have a follow-up question to you and others:

Even if a relatively small amount of precipitation may offset above-average melting in the daily SMB, is this actually good for the ice in the medium/long term? Or does the fact that anomalous precipitation is also presumably falling as rain at lower altitudes contribute to destabilisation/lubrication of glaciers, potentially increasing rates of glacier flow and the amount of calving?
The only thing I can add is that Greenland Mass loss (SMB minus calving)  in the 21st Century was quite a lot (3+ trillion tons 2002 to 2017).

Will be watching out for reports / new papers.

Attached is a graph from NASA / JPL Grace Data - no longer accessible as they've dumped access by ftp , and data access (also to GRACE-FO) now looks locked up for scientific user groups. Nothing for us who pay for the damn project.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 03, 2019, 02:46:36 PM
Thanks, Gerontocrat. I have a follow-up question to you and others:

Even if a relatively small amount of precipitation may offset above-average melting in the daily SMB, is this actually good for the ice in the medium/long term? Or does the fact that anomalous precipitation is also presumably falling as rain at lower altitudes contribute to destabilisation/lubrication of glaciers, potentially increasing rates of glacier flow and the amount of calving?
Will be watching out for reports / new papers***.

***And I forgot completely about this one even though I posted on AbruptSLR's thread as he had a similar one about the WAIS. Shoot me. Worth a read, I would say, as it was probably the reason I started obsessing about Greenland rain vs melt..

https://www.the-cryosphere.net/13/815/2019/
Increased Greenland melt triggered by large-scale, year-round cyclonic moisture intrusions
Marilena Oltmanns1, Fiammetta Straneo2, and Marco Tedesco3,4

4 Conclusions
By combining remote-sensing-based melt extent data and observations
from weather stations, we have shown that surface
melt is triggered by cyclonic weather events in summer and
winter. Through the advection of heat and moisture over large
portions of the ice sheet, these events lead to increases in
cloud cover, precipitation, an enhanced absorption of longwave
radiation and decreases in the albedo in the south and
near the coast. Previous studies have found that cyclonic rainfall
events in late summer have accelerated the glacial flow
(Doyle et al., 2015), suggesting that the identified melt events
can also trigger dynamic instabilities in the ice sheet. Since
the efficiency of the glacial flow was critically determined
by the seasonal condition of the subglacial drainage system
(Doyle et al., 2015), we mostly expect melt events in late
summer to have this effect
.
The strong, rapid and short-lived character of the temperature
increase, the high wind speeds, the precipitation
and their frequent occurrence, also excluding summer, distinguish
the investigated cyclonic weather events from the
anticyclones, centered over Greenland, that have previously
been recognized as the main driver of surface melting (Overland
et al., 2012; Fettweis et al., 2013; Hanna et al., 2013a,
2016). However, regarding the extended duration of melt
events in summer, we surmise that the identified melt triggers
can evolve into the previously described persistent high pressure
anomalies, which is supported by studies suggesting
that particularly intense and long-lasting atmospheric blocking
episodes in summer have been reinforced by cyclones
that preceded them (Neff et al., 2014; McLeod and Mote,
2015).




Title: Re: Greenland 2019 Melt Season
Post by: BenB on July 03, 2019, 05:16:51 PM
Thanks again, Gerontocrat. I actually read the whole paper, which made very interesting reading. It seems that as well as the impacts on dynamic processes that you bolded, the enhanced surface melting caused by greater cloud cover, increased absorption of LW radiation and lower albedo means that in summer the net impact of these precipitation events is to increase mass loss, even at the level of surface mass balance. In winter, on the other hand, there is a net SMB gain. One reason for this:

While in winter, most of the melting and precipitation occurs within the first 3 days of the events, in summer, melting, runoff and refreezing are still significantly amplified after 6 days.


Another interesting point is that:

The runoff–refreezing ratio is delayed compared to the others, being highest in August and falling off in November. This strong seasonality shows that most of the runoff associated with summer events occurs later in the season,

This could partly explain why at this time of summer any enhanced melt caused by the precipitation we're currently seeing is not (significantly) outweighing the additional accumulation of snow at higher altitudes. Or it could just be noise. Finally, they observed:

a northward and upslope shift of the boundary between rain/melting and snowfall, hence changing the balance between Greenland's mass gain and mass loss within a single weather event.

Climate change in action, and it will only get worse.
Title: Re: Greenland 2019 Melt Season
Post by: RoxTheGeologist on July 03, 2019, 07:06:12 PM
sin(30 degrees) = 1/2 is one i use a lot

perhaps we need a thread called quick math trix

sidd

SOOO far off topic. Sorry.

Read Fenyman's autobiography; he had a math race with a guy with an abacus and he uses a number of tricks to win. I believe it's at a time before calculators existed!

My favorite impressive math trick is 1/7ths; 0.142857 recurring.  They are blindingly easy to remember and the reaction to quoting fractions to 10 decimal places in your head is entertaining. My grandpa was a bank manager, and could add up columns of numbers blindingly quickly, far faster than I could type them into a adding machine. He was my role model :)

0.142857... (2x7, 4x7, 8x7 +1)
0.285714...
0.428571...
0.571428...
0.714285...
0.851428...

Its the same sequence, starting from each of the numbers, and the sequence of numbers is trivial to remember.
Title: Re: Greenland 2019 Melt Season
Post by: Alexander555 on July 03, 2019, 08:41:35 PM
What's the explanation for these 3 years with much bigger losses ?
Title: Re: Greenland 2019 Melt Season
Post by: b_lumenkraft on July 03, 2019, 09:10:58 PM
The melt just keeps going. Today it's south Greenland.

This is a GIF showing 3 frames from the RAMMB (a couple of hours) in M8 band.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 03, 2019, 09:35:10 PM
What's the explanation for these 3 years with much bigger losses ?
2012- amazing melt.
Other years - Don't know. Just depends on how much winter snowfall (mass gain) and how much summer melt + calving (mass loss). I do not have the data.

When if we ever see GRACE-FO data re 2017-18, we will likely see a mass GAIN as snowfall was far above average, melt was poor and perhaps calving less than usual.

Highly volatile - this year so far looks likely to be above average mass loss.
Title: Re: Greenland 2019 Melt Season
Post by: Phil. on July 03, 2019, 10:40:09 PM
Rox the last one should be 0.857142.. not 0.851428...   ;)
Title: Re: Greenland 2019 Melt Season
Post by: RoxTheGeologist on July 03, 2019, 11:08:14 PM
Oh yeah, typo lol. I didn't double check :)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 04, 2019, 10:25:23 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 3 July 2019

Again almost a word for word repeat of previous days' posts because this event just will not stop.

Melt remains strong and even stronger yet again, the maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, mainly in the South East, was not strong, and mass loss was around average.

Outlook - very dry?.

GFS Precipitation outlook for the next 5 days now looking  like very dry to drought over all Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed..

SMB mass change is a matter of which will prevail, precipitation and melt. It looks likely the SMB graph will above average SMB loss over the next few days.

And what is the prognosis for calving given all this melt and runoff ? Not a lot of news about icebergs in Baffin Bay and iceberg alley to be found.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high,  lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 04, 2019, 10:56:03 AM
And a couple of images from DMI to show why so many people are waiting for GRACE-FO to start producing data.

But GRACE-FO has started producing data, they've even got a scientists users group.
But "ftp" has been abandoned.
Nothing in a format useable by us "volk" what paid for it being published yet.
__________________________________________________________
A moan, about bloody scientists making sure peasants like me can only see what they let us see.

My guess is that one day it will be goodbye to anything other than YAML ASCII and NetCDF for holding data, i.e. goodbye to xls and .csv files from NSIDC and JAXA. At which time little ol' me will chuck the laptop in the bin..

See
https://earthdata.nasa.gov/esdis/eso/standards-and-references/yaml-encoding-ascii-format-for-grace-grace-fo-mission-data
and
https://podaac.jpl.nasa.gov/GRACE-FO
Quote
The GRACE-FO mission will continually generate the full records of Level 1-3 datasets which are listed in table below by three key partners​.  All GRACE-FO datasets are managed and distributed by PO.DAAC. To promote GRACE-FO data interoperability, all datasets are produced in either standard netCDF and/or ASCII YAML format, in compliance with PO.DAAC data best practices and NASA ESDIS metadata standards. Different from GRACE ASCII files, GRACE-FO ASCII files have been redesigned with its header constructed in the YAML format.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 05, 2019, 06:35:10 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 4 July 2019

Yet again almost a word for word repeat of previous days' posts because this event just will not stop.

Melt remains strong and even stronger yet again, the maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was very low, and mass loss was well above average.

GFS Precipitation outlook for the next 5 days now looking  like very dry to drought over all Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed..

SMB mass change is a matter of which will prevail, precipitation and melt. It looks likely the SMB graph will show above average SMB loss over the next few days.

And what is the prognosis for calving given all this melt and runoff ? Not a lot of news about icebergs in Baffin Bay and iceberg alley to be found.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high,  lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on July 05, 2019, 06:24:53 PM
It remains mild and dry close to the southern tip of Grønland:
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 06, 2019, 10:27:21 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 5 July 2019

Yet again almost a word for word repeat of previous days' posts because this event just will not stop.

Melt remains strong and even stronger yet again, the maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was almost zero, and as a result mass loss was greatly above average.

GFS Precipitation outlook for the next 5 days now looking  like very dry to drought over all Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed..

SMB mass change is a matter of which will prevail, precipitation or melt. It looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of more normal temperatures over Greenland after about a week. i.e. melt wiould continue, but at a more average rate. We will see.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high,  lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
[/quote]
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Rod on July 06, 2019, 05:43:37 PM
8 million Olympic size swimming pools in 5 days ...
Title: Re: Greenland 2019 Melt Season
Post by: Rod on July 07, 2019, 03:08:47 AM
Incredible image posted by Zack today showing some of the Greenland melt ponds.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on July 07, 2019, 05:57:24 AM
Most of these melt ponds are partially covered by floating ice.  I've read that some melt ponds do not freeze solid during the winter (which surprised me), but it explains the phenomenon demonstrated here, floating ice on melt ponds on glacial ice.  As a melt pond gets deeper and wider with today's warm temperatures, the floating ice will sever its connection to the shore, and even if 'thick', won't reach the shore of the larger pond.  A possibility is for a melt pond to drain after the surface freezes in the winter, leaving a cave, so that when re-filled, the pond will lift the 'lid' as described just above.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 07, 2019, 10:22:46 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 6 July 2019

No, I am not being lazy. The words are the same because the story is the same because this event just will not stop.

Melt remains strong and even stronger yet again, the maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was almost zero, and as a result mass loss was greatly above average.

GFS Precipitation outlook for the next 5 days still looking  like very dry to drought over most Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed..

SMB mass change is a matter of which will prevail, precipitation or melt. It looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of more normal temperatures over Greenland after about a week. i.e. melt would continue, but at a more average rate. We will see.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high,  lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
Title: Re: Greenland 2019 Melt Season
Post by: oren on July 07, 2019, 10:27:49 AM
This is simply relentless. 3-4 weeks of the same +2SD result. Much worse than a volatile high melt low melt situation. The meltwater has no chance to stabilize. This could cause some lake outburst and/or extra-strong calving around the Greenland perimeter.
Title: Re: Greenland 2019 Melt Season
Post by: Darvince on July 07, 2019, 02:01:58 PM
Today, tomorrow, and Tuesday look to be worse for the ice sheet before a slight cooldown afterwards. I'd expect the 7th, 8th, and 9th to all have highest mass loss for the year again (maybe approaching -10GT?) before it either stabilizes or declines afterwards.

... And, we still have five or so weeks left which could have another huge melt event like on 12th June. CFS (not very trustworthy) has weeks three thru five being well above average like the coming week.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on July 07, 2019, 03:45:00 PM
Most of these melt ponds are partially covered by floating ice.  I've read that some melt ponds do not freeze solid during the winter (which surprised me), but it explains the phenomenon demonstrated here, floating ice on melt ponds on glacial ice.  As a melt pond gets deeper and wider with today's warm temperatures, the floating ice will sever its connection to the shore, and even if 'thick', won't reach the shore of the larger pond.  A possibility is for a melt pond to drain after the surface freezes in the winter, leaving a cave, so that when re-filled, the pond will lift the 'lid' as described just above.

Most of the melt ponds in that image have floating ice. Would suggest that melt ponds not freezing solid is a common occurrence. I remember being surprised by this as well.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on July 07, 2019, 03:48:10 PM
Today, tomorrow, and Tuesday look to be worse for the ice sheet before a slight cooldown afterwards. I'd expect the 7th, 8th, and 9th to all have highest mass loss for the year again (maybe approaching -10GT?) before it either stabilizes or declines afterwards.

... And, we still have five or so weeks left which could have another huge melt event like on 12th June. CFS (not very trustworthy) has weeks three thru five being well above average like the coming week.

Albedo is so high along the coast now that heavy melt could continue despite lower temperatures if the skies stay clear.
Title: Re: Greenland 2019 Melt Season
Post by: RoxTheGeologist on July 07, 2019, 07:56:11 PM
Most of these melt ponds are partially covered by floating ice.  I've read that some melt ponds do not freeze solid during the winter (which surprised me), but it explains the phenomenon demonstrated here, floating ice on melt ponds on glacial ice.  As a melt pond gets deeper and wider with today's warm temperatures, the floating ice will sever its connection to the shore, and even if 'thick', won't reach the shore of the larger pond.  A possibility is for a melt pond to drain after the surface freezes in the winter, leaving a cave, so that when re-filled, the pond will lift the 'lid' as described just above.

Most of the melt ponds in that image have floating ice. Would suggest that melt ponds not freezing solid is a common occurrence. I remember being surprised by this as well.

A deep pool with the ice around the pool at 0°C. It can only lose energy from the top surface. Give that a nice cover of insulating snow. It does make sense when you think about it, but it is still really surprising. Also it would be terrifying to walk across an area of snow covered melt ponds!
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 08, 2019, 07:58:46 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 7 July 2019

No, I am not being lazy, honest. The words are the same because the story is the same because this event just will not stop.

Melt remains strong and even stronger yet again, at maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was almost zero again , and as a result mass loss was greatly above average.

GFS Precipitation outlook for the next 5 days still looking  like very dry over most of Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed..

SMB mass change is a matter of which prevails, precipitation or melt. It looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of more normal temperatures over Greenland after  a few days. i.e. melt would continue, but at a more average rate. We will see.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice).
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on July 08, 2019, 06:01:21 PM
The other day we were told the grey part of Gerontocrat's (DMI's) first graph shows the 30-year base period's daily melt extremes without the highest and lowest daily data points (and not considering 2012 as 2012 is after the base period ends).

The upper graph of the bottom pair of graphs also shows daily data, but this time daily mass gain/loss.  I presume it also removes the highest and lowest daily data points which might be from different year as in the first graph.  Now, 2019 shows as not being at the extreme.  But what does this mean?  This means to me that there were at least two years with more mass loss during the base period (and therefore not considering 2012's extremes).  Do we know what those years were?

And in the bottom graph showing accumulated mass gain/loss, it would be no problem if a particular pair of years had all the records (one for extreme gain and another for extreme loss), but in reality, some days Year X will hold the record and other days Year Y will hold the record.  I guess they just remove from the graph what ever year's accumulated data for that day was extreme, but keep the running total for when that year is in 2nd place.  [3rd place doesn't show on the graph either, but when it has an extreme day, it can move up to 2nd place (and show) or 1st place (and not show).]  On this graph we currently have 2012 approximately at the 2nd most loss (of base period years), and soon to be well below that mark, with 2019 close behind.

Title: Re: Greenland 2019 Melt Season
Post by: grixm on July 08, 2019, 06:16:42 PM
Today and tomorrow is pretty hot in Greenland. Not quite as hot as that event last month but with the melting momentum we already have, and low precipitation, I think it might be a big spike on the graph.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 09, 2019, 05:42:06 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 8 July 2019

Weekly updated of accumulated SMB attached.

No, I am not being lazy, honest, believe me.
The words are the same because the story is the same because this event just will not stop.

Melt remains strong and even stronger yet again, at maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was almost zero again (just a tad in the middle / east) , and as a result mass loss was greatly above average.

GFS Precipitation outlook for the next 5 days still looking  like very dry over most of Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed..

SMB mass change is a matter of which prevails, precipitation or melt. It looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of more normal temperatures over Greenland after a few days. i.e. melt would continue, but at a more average rate. But I've been saying that for days. We will see.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice).
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
[/quote]
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on July 10, 2019, 06:09:23 AM
I have been out for a few days, moving to a smaller house.   Do any of the reliable models show any improvement in the near future?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 10, 2019, 07:46:05 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 8 July 2019

No, I am not being lazy, honest, believe me. please.
The words are the same because the story is the same because this event just will not stop.

Melt remains strong and even stronger yet again, at maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was very low, and as a result mass loss was greatly above average.

GFS Precipitation outlook for the next 5 days still looking  like very dry over most of Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed..

SMB mass change is a matter of which prevails, precipitation or melt. It looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of more normal temperatures over Greenland after a few days. i.e. melt would continue, but at a more average rate. But I've been saying that for days. We will see.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice).
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
[/quote]
[/quote]
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: BenB on July 10, 2019, 10:56:50 AM
The Greenland albedo map has been updated, and there are some big changes. Anomalies in the south have in some cases turned positive from strongly negative, while there is now a big negative anomaly in the Humboldt/Petermann area in the north-west.
Title: Re: Greenland 2019 Melt Season
Post by: plg on July 10, 2019, 10:10:35 PM
Anybody seen this? I was not aware of the Ising model. (relates to melt ponds in general, but I guess it applies to Greenland as well?):
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 11, 2019, 08:49:57 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 10 July 2019

This event just will not stop.

Melt remains strong , almost at maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was low, and as a result mass loss was greatly above average.

GFS Precipitation outlook for the next 5 and even 10 days still looking  like very dry to drought over most of Greenland. High pressure stuck over Greenalnd

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed..

SMB mass change is a matter of which prevails, precipitation or melt. It looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of slightly less above average temperatures over Greenland after a few days. i.e. melt would continue, but at a more average rate. But I've been saying that for days. We will see.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice).
_____________________________________________________
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
Title: Re: Greenland 2019 Melt Season
Post by: aslan on July 11, 2019, 11:36:12 PM
Melting is so old fashioned, now Greenland is burning, more trendy ...

https://twitter.com/m_parrington/status/1149233824171094016
Title: Re: Greenland 2019 Melt Season
Post by: grixm on July 12, 2019, 08:16:48 AM
NSIDC had a bigger spike the last few days than DMI.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 12, 2019, 12:20:58 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 11 July 2019

This event just will not stop.

Melt remains strong , almost at maximum again for the year. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was low, and as a result mass loss was greatly above average, but a bit less than the previous day or two.

GFS Precipitation outlook for the next 5 10 days still looking  like very dry to drought over most of Greenland.
But in the following 5 days, it looks like a stronger weather system shovels copious quantities of warmth and moisture up Baffin bay, with precipitation - RAIN - all along the West coast.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed.. High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep most of Greenland dry, and maybe sunny? This should help to maintain melt.

SMB mass change is a matter of which prevails, precipitation or melt. It looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of slightly less above average temperatures over Greenland after a few days. i.e. melt would continue, but at a more average rate. But I've been saying that for days. We will see.

It becomes clear that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice).
_____________________________________________________

grixm in the post above notes that NSIDC's "Greenland Today" website shows a higher melt spike. This is usual. They are using a different model but the same definition of what is melt.
The link is http://nsidc.org/greenland-today/

But unless there is a good reason to change I will stick with DMI's analysis for the sake of consistency.
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on July 12, 2019, 08:41:58 PM
Why do the DMI and the NSIDC melt rates differ so much in detail? Do these institutions use different measures to calculate the melt? And which of the two is better in describing what really happens with the ice sheet?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 12, 2019, 09:05:34 PM
Why do the DMI and the NSIDC melt rates differ so much in detail? Do these institutions use different measures to calculate the melt? And which of the two is better in describing what really happens with the ice sheet?

Don't know. I believe the DMI uses a higher resolution  (see the size of the pixels on the NSIDC melt map)

You could e-mail NSIDC. They seem more likely to respond (and or the University of Georgia). I have e-mailed DMI before & got nowhere.
Title: Re: Greenland 2019 Melt Season
Post by: HapHazard on July 12, 2019, 09:33:10 PM
This thread is like Groundhog Day.

Amazing. (and not in a good way)

Thanks for all the postings, G.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 13, 2019, 05:27:30 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 12 July 2019

This event has reduced a bit. Temporarily?

Melt remains strong , but has dropped a bit. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was almost non-existent, and as a result mass loss was a bit more than the previous day or two despite a reduction in melt.

GFS Precipitation outlook for the next 5 days still looking  like very dry to drought over most of Greenland.
But in the following 5 days, it looks like a stronger weather system shovels copious quantities of warmth and moisture up Baffin bay, with precipitation - RAIN - all along the West coast. This could increase melt.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed.. High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep most of Greenland dry (apart from the West coastal fringe), and maybe sunny? This should help to maintain melt.

SMB mass change is a matter of which prevails, precipitation or melt. It still looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of slightly less above average temperatures over Greenland after a few days. i.e. melt would continue, but at a more average rate. But I've been saying that for days. We will see.

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________

grixm in the post above notes that NSIDC's "Greenland Today" website shows a higher melt spike. This is usual. They are using a different model but the same definition of what is melt.
The link is http://nsidc.org/greenland-today/

But unless there is a good reason to change I will stick with DMI's analysis for the sake of consistency.
Note from DMI

When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.


Note from me to any denier creeps out there:
From 2002 to 2017 Greenland lost over 3 thousand billion tons of mass, an average of nearly 300 billion tons per annum. This is about the same as the average annual mass loss of ice from the entire Arctic Seas. https://climate.nasa.gov/vital-signs/ice-sheets/

This is simply because mass loss from glaciers calving exceeds mass gain on the surface from snowfall.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 14, 2019, 02:46:04 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 13 July 2019

This event has reduced a bit again. Temporarily?

Melt remains strong , but has dropped a bit more. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was ZERO?, and as a result mass loss was a bit more than the previous day or two despite a reduction in melt.

GFS Precipitation outlook for the next 5 days still looking  like very dry over most of Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed.. High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep most of Greenland dry (apart from the West coastal fringe), and maybe sunny? This should help to maintain melt.

SMB mass change is a matter of which prevails, precipitation or melt. It still looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of slightly less above average temperatures over Greenland after a few days. i.e. melt would continue, but at a more average rate. But I've been saying that for days. We will see.

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 15, 2019, 07:42:23 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 13 July 2019

Nothing changed in this post except the date.

This event has reduced a bit again. Temporarily?

Melt remains strong , but has dropped a bit more. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see strong short-term spikes.

Precipitation, was ZERO?, and as a result mass loss was a bit more than the previous day or two despite a reduction in melt.

GFS Precipitation outlook for the next 5 days still looking  like very dry over most of Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed.. High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep most of Greenland dry (apart from the West coastal fringe), and maybe sunny? This should help to maintain melt.

SMB mass change is a matter of which prevails, precipitation or melt. It still looks likely the SMB graph will show above average SMB loss over the next few days.

Signs of slightly less above average temperatures over Greenland after a few days. i.e. melt would continue, but at a more average rate. But I've been saying that for days. We will see.

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Title: Re: Greenland 2019 Melt Season
Post by: grixm on July 15, 2019, 09:17:45 AM
So basically we are pretty much at the mean minimum accumulated SMB already, and we're just halfway through the season!
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on July 15, 2019, 10:05:42 PM
Dry, mild and mostly sunny - that's what Wetteronline forecasts for July 15 to July 28 for Narssarsuaq, South Grønland.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 16, 2019, 06:28:21 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 15 July 2019

Nothing changed in this post except the date.

This event has reduced a bit again. Temporarily?

Melt but has dropped to around average. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see short-term spikes.

Precipitation, was almost zero, and as a result despite average melt SMB (Surface Mass Balance) loss was very much above average.

GFS Precipitation outlook for the next 5 days still looking  like very dry over most of Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed.. High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep most of Greenland dry (apart from the West coastal fringe), and maybe sunny? This should help to maintain melt.

SMB mass change is a matter of which prevails, precipitation or melt. It still looks likely the SMB graph will show above average SMB loss over the next few days due to low precipitation.

Signs of slightly less above average temperatures over Greenland after a few days. i.e. melt would continue, but at a more average rate.

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include 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 Melt Season
Post by: gerontocrat on July 16, 2019, 07:34:06 PM
DMI have got around to adding the weekly update of the Accumulated SMB Anomaly.

Dodgy gif attached . it plays thrice & then stops, probably forever.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on July 16, 2019, 08:02:03 PM
DMI have got around to adding the weekly update of the Accumulated SMB Anomaly.

Dodgy gif attached . it plays thrice & then stops, probably forever.

Wow! Love it.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 17, 2019, 07:56:25 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 15 July 2019

Almost nothing changed in this post except the date.

Melt at a little bit above average. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see short-term spikes.

Precipitation, very low, and as a result despite average melt SMB (Surface Mass Balance) loss was very much above average.

GFS Precipitation outlook for the next 5 days still looking  like very dry over most of Greenland, but with increasing chance of moist warm winds from the south into Baffin Bay bringing rain to the West coast.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as final sea ice melt out is completed.. High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep most of Greenland dry (apart from the West coastal fringe), and maybe sunny? This should help to maintain melt.

SMB mass change is a matter of which prevails, precipitation or melt. It still looks likely the SMB graph will show above average SMB loss over the next few days due to low precipitation.

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on July 17, 2019, 02:08:47 PM
Do you have a prediction on when Baffin Bay will melt out?   It is probably in the 2019 Melt thread, haven't looked there yet today....
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 17, 2019, 05:28:55 PM
Do you have a prediction on when Baffin Bay will melt out?   It is probably in the 2019 Melt thread, haven't looked there yet today....
Only scraps left now, anyway.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 18, 2019, 07:09:34 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 17 July 2019

Not a lot changed in this post except the date (which I remembered to change this time).

Melt at a little bit above average. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see short-term spikes.

Precipitation low, and as a result SMB (Surface Mass Balance) loss was above average.

GFS Precipitation outlook for the next 5 days still looking  like very dry over East f Greenland, but with increasing chance of moist warm winds from the south into Baffin Bay bringing rain and warmth to the West coast.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as the final scraps of sea ice melt out is completed.. High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep most of Greenland dry (apart from the West coastal fringe), and maybe sunny? This should help to maintain melt.

SMB mass change is a matter of which prevails, precipitation or melt. It still looks likely the SMB graph will show above average SMB loss over the next few days due to low precipitation or perhaps rainfall at lower elevations along the West coast..

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
Title: Re: Greenland 2019 Melt Season
Post by: grixm on July 18, 2019, 06:03:37 PM
Next few days will be hot in Greenland. Will probably see another spike in melt. Some precip too though, so don't know how the SMB will end up.
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on July 18, 2019, 08:47:24 PM
I found this article interesting, especially the 2:12 video where they talk about the model results, and show the model progressing through year 2300.   

The screen capture is of the models at year 2300.  The pink areas in the picture represent exposed bedrock from the ice sheet retreat.

https://climate.nasa.gov/news/2883/study-predicts-more-long-term-sea-level-rise-from-greenland-ice/
Title: Re: Greenland 2019 Melt Season
Post by: philopek on July 18, 2019, 10:27:04 PM
I found this article interesting, especially the 2:12 video where they talk about the model results, and show the model progressing through year 2300.   

The screen capture is of the models at year 2300.  The pink areas in the picture represent exposed bedrock from the ice sheet retreat.

https://climate.nasa.gov/news/2883/study-predicts-more-long-term-sea-level-rise-from-greenland-ice/

Great find, thanks.

I'm surprised that they hire from Switzerland, ahh... forgot, he thought to go somewhere where there will still be glaciers in a few years, considering how quickly they retreat in the alps.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 19, 2019, 07:08:39 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 18 July 2019

Not a lot changed in this post except the date (which I remembered to change this time).

Melt at a little bit above average. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see short-term spikes.

Precipitation low, and as a result SMB (Surface Mass Balance) loss was above average.

GFS Precipitation outlook for the next 5 days still looking  like very dry over East Greenland, but with increasing chance of moist warm winds from the south into Baffin Bay bringing rain and warmth to the West coast.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as the final scraps of sea ice melt out is completed.. High pressure has been, is, and will be stuck er Greenland until ....? This is likely to keep most of Greenland dry (apart from the West coastal fringe), and maybe sunny? This should help to maintain melt.

SMB mass change is a matter of which prevails, precipitation or melt. It still looks likely the SMB graph will show above average SMB loss over the next few days due to low precipitation or perhaps rainfall at lower elevations along the West coast..

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 20, 2019, 11:40:49 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 19 July 2019

Melt quite a bit above average. Again concentrated in the West and the South. I am sure the persistence of this strong melt is unusual, as normally we just see short-term spikes.

Precipitation in central west coast, and as a result SMB (Surface Mass Balance) loss was only just above average.

GFS Precipitation is looking a bit weird. Over the next 2 to 3 days a ltlle atmospheric river comes out of Hudson Bay, crosses Ellesmere Island and Baffin Bay and splats pecipitation on the central West coast. On Monday night it stops, and outlook for the next 5 days and more looking   very dry over all Greenland.

Melt. Temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as the final scraps of sea ice melt out is completed.. High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep most of Greenland dry (apart from the West coastal fringe until Monday), and maybe sunny? This should help to maintain melt.

SMB mass change is a matter of which prevails, precipitation or melt. The 19th July was a classic demo of how although melt was well above average at the peak of the melting season, a bit of precipitation on just one part of the West coast sent SMB loss back to average.

It still looks likely the SMB graph will show above average SMB loss over the next few days after Monday due to low precipitation or perhaps rainfall at lower elevations along the West coast..

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation (now) hypothesis remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.

Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on July 20, 2019, 05:53:08 PM
Any response to my July 8 question (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg211880.html#msg211880)?  (or refutation of my interpretation  :) )
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 20, 2019, 08:41:15 PM
Any response to my July 8 question (https://forum.arctic-sea-ice.net/index.php/topic,2543.msg211880.html#msg211880)?  (or refutation of my interpretation  :) )
I don't know.
Why they don't use +1SD & +2SD grey bands is a mystery.

But SMB is a result of melt (-) and precipitation (+) or (-) if rain and the model assumes run-off?
The 2019 data shows clearly that even moderate precipitation can overwhelm melt.
So maybe although 2012 had that huge melt it also had quite a lot of precipitation.

I tried to find some precipitation data  and tried a download from the world bank site https://climateknowledgeportal.worldbank.org/download-data

It was supposed to be a .csv file. It killed my spreadsheet and I had to restart the computer.
I am not having a good day.

And DMI are not renowned for replying to requests for info or data.
Some mysteries must remain a mystery unless someone else finds out.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on July 20, 2019, 09:06:41 PM
Uh oh, there goes my influence!  :o  Sorry you had a bad day (but it can get better, right?) on my account.  Thanks for looking.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 21, 2019, 12:52:31 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 20 July 2019

Melt approaching a new maximum for the year. I am sure the persistence of this strong melt is unusual, as normally we just see short-term spikes.

Precipitation in central west coast, and as a result SMB (Surface Mass Balance) loss was just a bit more above average due to higher melt.

GFS Precipitation is still looking a bit weird. Over the next 2 to 3 days a little atmospheric river comes out of Hudson Bay, crosses Ellesmere Island and Baffin Bay and splats precipitation on the central West coast. On Monday night it stops, and outlook for the next 5 days and more looking   very dry over all Greenland.

Melt. Greenland looks as if it will cool down somewhat from next mid-week, though temperatures above freezing around most of the coast in the next week. The SST anomalies in Baffin Bay can only increase as the final scraps of sea ice melt out is completed.. High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep most of Greenland dry (apart from the West coastal fringe until Monday), and maybe sunny? Will melt moderate or stay high?

SMB mass change is a matter of which prevails, precipitation or melt. The 19th and 20th July was a classic demo of how although melt was well above average at the peak of the melting season, a bit of precipitation on just one part of the West coast sent SMB loss back to average.

It still looks likely the SMB graph will show above average SMB loss over the next few days after Monday due to low precipitation or perhaps rainfall at lower elevations along the West coast..

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation (now) hypothesis remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
Title: Re: Greenland 2019 Melt Season
Post by: Tor Bejnar on July 21, 2019, 02:40:11 PM
Regardless how much melting is occurring in Greenland these days, 2012 was worse.  Because of the (presumed related) juxtaposition of 2012 ASI loss with 2012 Greenland ice loss, I'm grateful to this year's 'conservatism', presuming it will have an influence on its ASI neighbor to the north.  It's a 'Thank God for little things,' feeling I carry.
Title: Re: Greenland 2019 Melt Season
Post by: Stephen on July 22, 2019, 05:16:53 AM
When the Antarctic sea-ice was increasing in 2012,2013,2014 one of the contributing factors proposed was that increasing fresh ice meltwater raises the temp at which sea water will freeze.  So a fresh meltwater layer freezes more easily.  So more ice shelf melt means more sea-ice.

At least that was a theory that I read at the time.  So more Greenland melt may actually contribute to more Arctic sea-ice.  Personally, I do not think that the contribution would be significant but the corollary is that less Greenland melt means slightly more saline coastal ocean surface and so a lower melting temp. 
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 22, 2019, 01:40:31 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 21 July 2019

On this day

Melt approached and surpassed the previous maximum for the year. Still predominantly in the West. I am sure the persistence of this strong melt is unusual, as normally we just see short-term spikes.

Precipitationup  in central west coast, and as a result SMB (Surface Mass Balance) loss was only a bit above average despite the higher melt.
_______________________________________________
GFS Outlook

Precipitation outlook changed. North and West to be very dry for the mext week, while precipitation gradually comes in to the south and east

Melt. Greenland looks as if it will cool down somewhat from next mid-week, though temperatures above freezing around most of the coast in the next week. 

Temperatures look to be a bit above above average for the next few days.The SST anomalies in Baffin Bay can only increase as the final scraps of sea ice melt out is completed..

High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep much of Greenland dry (apart from the coastal fringes?) and maybe sunny? Will melt moderate or stay high?
____________________________________________
SMB mass change is a matter of which prevails, precipitation or melt. The 19th to 21st July was a classic demo of how although melt was well above average at the peak of the melting season, a bit of precipitation on just one part of the West coast sent SMB loss back to average.

It still looks likely the SMB graph will show above average SMB loss over the next few daysas precipitation reduces.

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation (now) hypothesis remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 23, 2019, 09:18:47 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 22 July 2019

On this day

Melt yet again approached and surpassed the previous maximum for the year. Still predominantly in the West. I am sure the persistence of this strong melt is very unusual, as normally we just see short-term spikes.

Precipitationup from the central west, and as a result SMB (Surface Mass Balance) loss was only a bit above average despite the higher melt.
_______________________________________________
GFS Outlook

Precipitation outlook changed. Greenland very dry for the next 5 days.

Melt / Temperatures. Greenland looks as if it will cool down somewhat from next mid-week, though temperatures above freezing around most of the coast in the next week, especially in the West.  The SST anomalies in Baffin Bay can only increase as the final scraps of sea ice melt out is completed..

High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep much of Greenland dry (apart from the coastal fringes?) and maybe sunny? Will melt moderate or stay high?
____________________________________________
SMB mass change is a matter of which prevails, precipitation or melt. The 19th to 22nd July was a classic demo of how although melt was well above average at the peak of the melting season, a bit of precipitation on just one part of the West coast sent SMB loss back to average.

It still looks likely the SMB graph will show above average SMB loss over the next few days as precipitation reduces.

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation (now) hypothesis remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include 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 Melt Season
Post by: FrostKing70 on July 23, 2019, 05:17:54 PM
Interesting graph of Greenland ice sheet mass loss 2002 to 2017.   Eyeballing the trend, it appears to be very predictable for this time frame.

There should be new data available later this year:

https://climate.nasa.gov/vital-signs/ice-sheets/

 
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on July 23, 2019, 05:36:52 PM
You must be tired hitting copy+paste.... this thing that we are observing is not changing much....
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 24, 2019, 01:45:42 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 23 July 2019

On this day

Melt High but down a bit. Still predominantly in the West. I am sure the persistence of this strong melt is very unusual, as normally we just see short-term spikes.

Precipitation minimal, and as a result SMB (Surface Mass Balance) loss substantially above average despite the higher melt.
_______________________________________________
GFS Outlook

Precipitation outlook changed. Greenland North & West very dry for the next 5 days. Some precipitation arriving in the south and on the east coast - partly rain?

Melt / Temperatures. Greenland looks as if it will cool down somewhat from next mid-week, though temperatures above freezing around most of the coast in the next week, especially in the West.  The SST anomalies in Baffin Bay can only increase as the final scraps of sea ice melt out is completed..

High pressure has been, is, and will be stuck over Greenland until ....? This is likely to keep much of Greenland dry (apart from the coastal fringes?) and maybe sunny? Will melt moderate or stay high?
____________________________________________
SMB mass change is a matter of which prevails, precipitation or melt. The 19th to 22nd July was a classic demo of how although melt was well above average at the peak of the melting season, a bit of precipitation on just one part of the West coast sent SMB loss back to average.

It still looks likely the SMB graph will show above average SMB loss over the next few days as precipitation will not be great.

It seems clear (to me at least) that precipitation, or the lack of it, may determine the overall SMB loss during the melting season at least as much as melt. My speculation (now) hypothesis remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year.

At the moment 2019 is giving 2012 a run for its money (as it is for Arctic Sea Ice). How linked are they? If this melt declines to average will Arctic Sea Ice melt reduce as well (or vice-versa)?
_____________________________________________________
Note from DMI
When comparing melt with the surface mass balance under ”Daily change”, note that melting can occur without surface mass loss since the meltwater can refreeze in the underlying snow. Likewise, surface mass loss can occur without melting due to sublimation.

The map illustrates how the surface of the Greenland Ice Sheet gains and loses mass on a daily basis. This is known as the surface mass balance. It does not include the mass that is lost when glaciers calve off icebergs and melt as they come into contact with warm seawater.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 24, 2019, 01:52:52 PM
You must be tired hitting copy+paste.... this thing that we are observing is not changing much....
And that's the point. What persistent and continual high melt is doing to the Greenland glaciers and calving is a mystery.

GRACE-FO is producing science quality data. This was supposed to include updates to ice-sheet mass changes to give us a clue about calving an glacial melt. But I have seen nothing in a format of use to ordinary folk.

And yes, there are many times I think of reducing posts to just one a week.
Title: Re: Greenland 2019 Melt Season
Post by: Mozi on July 24, 2019, 01:56:52 PM
I appreciate the daily updates, but you might make the caveats/notes section a weekly occurrence?
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on July 24, 2019, 01:57:36 PM
speculation (now) hypothesis remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year...

I think they are linked. With lack of warming and melting Greenland stays colder and acts as the a center of the polar vortex affecting the weather in the Arctic. If both greenland and arctic experience highs we see what we saw in 2012 and this year. Just a hunch...
Title: Re: Greenland 2019 Melt Season
Post by: peterlvmeng on July 24, 2019, 02:07:33 PM
speculation (now) hypothesis remains that in 2012, even though melt was spectacularly high, lack of precipitation was as or more important than melt in the unprecedented SMB loss that year...

I think they are linked. With lack of warming and melting Greenland stays colder and acts as the a center of the polar vortex affecting the weather in the Arctic. If both greenland and arctic experience highs we see what we saw in 2012 and this year. Just a hunch...

Yeah, much of my concern come from when the arctic sea ice free in summer, what about the Greenland? I think the SST of arctic ocean will dramatically rise because of no sea ice absorbing heat. The Greenland is circled by warm current. So how fast and how many ice cap will disintegrate into the ocean? how fast and how much the sea surface level will rise?
Title: Re: Greenland 2019 Melt Season
Post by: TerryM on July 24, 2019, 02:39:56 PM

And yes, there are many times I think of reducing posts to just one a week.


FWIW
I've come to look forward to your daily recaps.


Your labors are very much appreciated!
Terry
Title: Re: Greenland 2019 Melt Season
Post by: wili on July 24, 2019, 02:41:22 PM
Hear, hear!
Title: Re: Greenland 2019 Melt Season
Post by: oren on July 24, 2019, 05:24:23 PM
I appreciate the daily updates, but you might make the caveats/notes section a weekly occurrence?
Same here. Love the dailies, could do without the repeating text. Just put a few lines in, and post the rest every week for the trolls and occasional readers.
Title: Re: Greenland 2019 Melt Season
Post by: nanning on July 24, 2019, 06:17:38 PM
I agree with oren. Gerontocrat very thankful for your efforts, creativity and smartness. You are some kind of a 'pillar' on this forum I think.
Title: Re: Greenland 2019 Melt Season
Post by: grixm on July 25, 2019, 08:18:10 AM
If the 0z GFS verifies, Greenland will see an extreme melt event starting at +120h. At daytime 90% of the island will have above freezing surface air temperature and the coast will reach 20C+, all lasting several days!

(https://i.imgur.com/7s38B2P.png)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 25, 2019, 08:45:57 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 24 July 2019

On this day

Melt High but down a bit. Still predominantly in the West. .

Precipitation minimal, and as a result SMB (Surface Mass Balance) loss substantially above average despite the slightly lower melt.
_______________________________________________
GFS Outlook

Precipitation 5 day outlook. Greenland North & West very dry for the next 5 days. Some precipitation in the south and on the east coast - partly rain?

Melt / Temperatures. Extreme warmth Monday 29 to Wed 31 July. Will it happen? If it does, melt % will likely be new maxima for the year.

High pressure has been, is, and will be stuck over Greenland until ....?
____________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: BornFromTheVoid on July 26, 2019, 09:53:48 AM
The heat from Europe is now beginning to make its way north west towards Greenland, via Iceland. You can track the movement on the 850hPa anomalies in the animation below.

(https://amz.nwstatic.co.uk/monthly_2019_07/Anim_850.gif.3a133cd9b00f47c37a8c9e5c082c3a13.gif)

By the time it arrives, as mentioned by grixm, surface temps are widely above 0C across the ice sheet, with plenty of very warm spots around the coastal fringes.

(https://amz.nwstatic.co.uk/monthly_2019_07/GreenT2m.png.dbf6410aa3e210b9e88774efe8967eb0.png)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 26, 2019, 12:46:11 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 25 July 2019

Just when I think about reducing activity on this thread as nothing much is changing....

On this day

Melt Down to not much above average. Still predominantly in the West. .

Precipitation low, and as a result SMB (Surface Mass Balance) loss well above average despite the lower melt.
_______________________________________________
GFS Outlook

Precipitation 5 day outlook. Greenland North & West very dry for the next 5 days. Some precipitation pushing in from the south and towards especially the east coast - looking like rain at lower altitudes.

Melt / Temperatures. Today and Saturday looking average for the time of year but then..

For once a predicted major weather event looks likely to happen. Warmer starting on Sunday, reaching extreme highs on Tuesday, and staying much above average to perhaps Saturday.

If the Tuesday extreme happens, melt will likely be a new maximum for the year and cover most of Greenland.
 
High pressure has been, is, and will be stuck over Greenland until ....?
____________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: grixm on July 26, 2019, 07:54:31 PM
I was surprised to see that the upcoming potential greenland melt event made the top of my national news site NRK.no: https://i.imgur.com/e4Y4doz.jpg

I thought keeping up with this stuff was a bit too niche for mainstream media
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on July 26, 2019, 09:24:33 PM
gerontocrat,
thanks for your daily postings and analyses.
I recognize that surface melt on Grønland has been and very likely will be above average for at least five weeks in a row. Has that ever happened before or is this unprecendented?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 26, 2019, 09:43:36 PM
gerontocrat,
thanks for your daily postings and analyses.
I recognize that surface melt on Grønland has been and very likely will be above average for at least five weeks in a row. Has that ever happened before or is this unprecendented?
Don't know.
No nice ASCII or .csv files at DMI. Experts only,  think.

But a nice if oldish paper gives a clue (http://prudence.dmi.dk/data/temp/RUM/HIRHAM/GREENLAND/MottramEtAl2017.pdf)

Data to 2014 shows an increase in snow-melt - 2012 is still No.1 by far. Should get some comparisons late in the year from NSIDCs Greenland today and DMI do an annual report as well.



Title: Re: Greenland 2019 Melt Season
Post by: Rod on July 27, 2019, 01:27:23 AM
More bad news for the ice sheet.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 27, 2019, 08:46:41 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 26 July 2019

Just when I think about reducing activity on this thread as nothing much is changing....

On this day melt and SMB loss very much at average. The calm before the storm?

Melt Down to not much above average. Still predominantly in the West. .

Precipitation a bit higher, and as a result SMB (Surface Mass Balance) loss only just above average in line with the lower melt.
_______________________________________________
GFS Outlook

Precipitation 5 day outlook. Greenland North & West very dry for the next 5 days. Precipitation, that could be high, pushing in from the south and towards especially the east coast - looking like rain at lower altitudes.

Melt / Temperatures. Today and Saturday looking average for the time of year but then..

For once a predicted major weather event looks even more likely to happen. Warmer starting on Sunday, reaching extreme highs on Tuesday, and staying much above average to perhaps Saturday. The maximum temperatures for the next 5 days from GFS shows that nearly all of Greenland will get some melt at some time over the next 5 days - and in some low altitude places extreme melt for long periods. See post from Rod above.

High pressure has been, is, and will be stuck over Greenland until ....?
____________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 27, 2019, 08:51:16 AM
The post from Rod talks about albedo. Attached is the status as at 25 July. Red and yellow = darker
Also attached cumulative SMB anomaly map.

The end of season analyses from DMI and NSIDC's Greenland Today will be interesting.
Title: Re: Greenland 2019 Melt Season
Post by: grixm on July 27, 2019, 09:51:38 PM
NSIDC has a new interactive melt map where you can browse melt extent and temperature readings for different dates: https://greenland-measures.labs.nsidc.org/
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 27, 2019, 10:46:24 PM
 GRACE-FO is producing new mass loss data that I can read. Also posted on what's new.

We will get a much better handle on what's going on from now on.
Title: Re: Greenland 2019 Melt Season
Post by: Ktb on July 28, 2019, 07:32:59 AM
GRACE-FO is producing new mass loss data that I can read. Also posted on what's new.

We will get a much better handle on what's going on from now on.

Best news I've heard in quite a while!!!
Title: Re: Greenland 2019 Melt Season
Post by: oren on July 28, 2019, 07:40:37 AM
Thank you Gerontocrat. At last!
The good news: mass loss was much below average in the last two years.
The not so good news: SMB data gave hope for no mass loss, but it turns out calving and ocean melting were greater (or that SMB modelling is imperfect).
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 28, 2019, 09:00:14 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 26 July 2019


On this day melt and SMB loss very much at average. The calm before the storm?

Melt Down to not much above average. Still predominantly in the West. .

Precipitation a bit higher, and as a result SMB (Surface Mass Balance) loss only just above average in line with the lower melt.
_______________________________________________
GFS Outlook

Precipitation 5 day outlook. Greenland North & West very dry for the next 5 days. Precipitation, that could be high, pushing in from the Atlantic towards the east coast - looking like rain at lower altitudes.

Melt / Temperatures.
For once a predicted major weather event looks even more likely to happen. Warmer starting today (Sunday), reaching extreme highs on Tuesday/Wednesday, and staying much above average to perhaps Saturday. Nearly all of Greenland will get some melt at some time over the next 5 days - and in some low altitude places extreme melt for long periods.

It will be interesting to see how much the higher precipitation offsets the higher melt in the SMB gain / loss equation.
____________________________________________
High pressure has been, is, and will be stuck over Greenland until ....?
Part of a major weather change in the whole Arctic Basin?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 28, 2019, 01:36:53 PM
There are times when one would like to shoot a scientist or two. This is one of them.

GRACE-FO
I have had a good look at the new GRACE-FO ice loss data.  The technical notes say

"The definition of 25 major drainage basins for the AIS and 7 drainage basins for the GIS, as well as the inversion procedure based on a forward modelling approach follows Sasgen et al. (2013) and Sasgen et al. (2012), respectively. "

Next stage, find a map. So after hitting a paywall a few times, bingo.....

https://www.researchgate.net/publication/233811055_Timing_and_origin_of_recent_regional_ice-mass_loss_in_Greenland

Attached is the map- Basins A to G.
There is a table of mass loss 2003-2009 by 7 basins A to G

The data file has Basins 301 to 308.  Yes, eight. Graph attached

8 vs 7. In the same order? Don't know.
But there is a table of mass loss 2003-2009.

NASA - IceSat
While hunting for the definitive map of the 7 drainage basins I come across

https://icesat4.gsfc.nasa.gov/cryo_data/ant_grn_drainage_systems.php

and what do I find - Greenland's  8 - eight - Drainage Basins. (map attached).
If you can handle this stuff (I can't) the lat longs of the drainage basisn are in this file.
https://icesat4.gsfc.nasa.gov/cryo_data/drainage_divides/GrnDrainageSystems_Ekholm.txt

 and a quote:-
Quote
Drainage Systems and Divides
Ice sheet drainage systems were delineated to identify regions broadly homogeneous regarding surface slope orientation relative to atmospheric advection, and additionally in the case of Antarctica, denoting the ice sheet areas feeding large ice shelves. Systems and sub-systems include one or more primary basins, each identifiable with a particular outlet glacier or ice stream that drains the interior of an ice sheet, plus secondary basins that complete the periphery of an ice sheet and are normally ignored in net mass budget estimates based on input-minus-output methods. The drainage system schemes for Antarctica and Greenland cover the entire area within the coterminous coastline.

Both GRACE and IceSat are NASA projects.
My guess is that the 2012 analysis by Sasgen et al has been changed to add an extra basin, but they have not noted that in the documentation

But what do I know?


I am not looking at Antarctica yet, frightened of losing the will to live.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 29, 2019, 12:34:06 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 28 July 2019

On this day...

Melt up a bit
Precipitation much higher, all in the SE quadrant, overwhelming slightly higher melt and as a result
SMB (Surface Mass Balance) much below average.
_______________________________________________
GFS Outlook

Precipitation 5 day outlook. Greenland North & West very dry for the next 5 days. Precipitation, that could be high, pushing in from the Atlantic towards the east coast - looking like rain at lower altitudes.

Melt / Temperatures.
For once a predicted major weather event looks inevitable. Spike in temperatures starting today (Monday), reaching extreme highs on Tuesday & Wednesday, and staying much above average to perhaps Saturday. Nearly all of Greenland will get some melt at some time over the next 5 days - and in some low altitude places extreme melt for long periods.

It will be interesting to see how much the higher precipitation offsets the higher melt in the SMB gain / loss equation. And how does the DMI model deal with precipitation falling as rain in lower altitudes?
_______________________________________________
The Accumulated SMB Anomaly map shows the extreme contrast between the SE coast and the West coast. In theory, the DMI model should show the SMB gains and losses by drainage basins. GRACE-FO data is also by drainage basins.

If the drainage basins used are the same (!?), and if IceSat drainage basins are the same (!?), measurements of mass loss / gain from calving, melt and precipitation and consequential topographical change by Greenland's individual drainage basins would be possible.
____________________________________________
High pressure has been, is, and will be stuck over Greenland until ....?
Part of a major weather change in the whole Arctic Basin?
Title: Re: Greenland 2019 Melt Season
Post by: Klondike Kat on July 29, 2019, 04:25:43 PM
A slight change from your regular post.  Thank you for your continuing updates.
Title: Re: Greenland 2019 Melt Season
Post by: Frivolousz21 on July 29, 2019, 11:32:08 PM
All of that precip over SE Greenland has to be rain the freeze level is close to 3000M.

I hope that DMI model doesn't record it as snow.  There is no way.
Title: Re: Greenland 2019 Melt Season
Post by: philopek on July 30, 2019, 12:53:04 AM
All of that precip over SE Greenland has to be rain the freeze level is close to 3000M.

I hope that DMI model doesn't record it as snow.  There is no way.

If the freeze level is around 3000m it can snow down to 2500m (approx) because it can snow up to 4C and usually does till 2C.

Depending on the slope / gradient this can be a huge are, hence the "ALL" term can in fact be around "half"
Title: Re: Greenland 2019 Melt Season
Post by: Csnavywx on July 30, 2019, 01:26:38 AM
500m is usually the maximum freeze level for snow. To get it with surface temperatures at 2-4C, you need drier sub-cloud air, for evaporational cooling to do its work on keeping hydrometeors frozen to the surface. That's a bit of a special case. With this kind of setup, the low level warm wedge (driven by advection) is likely to be pretty stout. It only takes 10 J/kg of excess heat (above freezing) to prevent snow from reaching the ground.

We'll find out for sure on the DMI figures since almost nowhere will be getting snow starting tonight/tomorrow. Even the summit looks to get above freezing.

Funny, I seem to remember a recent paper about rain events on a future Greenland ice sheet wrt mass loss/gain.
Title: Re: Greenland 2019 Melt Season
Post by: philopek on July 30, 2019, 01:39:14 AM
500m is usually the maximum freeze level for snow. To get it with surface temperatures at 2-4C, you need drier sub-cloud air, for evaporational cooling to do its work on keeping hydrometeors frozen to the surface. That's a bit of a special case. With this kind of setup, the low level warm wedge (driven by advection) is likely to be pretty stout. It only takes 10 J/kg of excess heat (above freezing) to prevent snow from reaching the ground.

We'll find out for sure on the DMI figures since almost nowhere will be getting snow starting tonight/tomorrow. Even the summit looks to get above freezing.

Funny, I seem to remember a recent paper about rain events on a future Greenland ice sheet wrt mass loss/gain.

To be honest, in this case I don't care much about theories because i spent 50 years in places where the temperatures hovered often if not mostly between zero and 5C once westerly winds braught precipitation.

During this entire period I carefully studied the temperatures related to the kind of precipitation
and in case of snowfall it's quality, flake-size etc.

Result is what I wrote above, it mostly snows till 2C and can snow till 4C. Or in other words, I don't remember snowfall above 5C but I do remember snowfall between 2-4C.

Why does it matter?

Because roughly 100m account for 1C (roughly and generally speaking) and if the freezing temps are around 3000m that makes it snowing down to 2500m if conditions are right but certainly down to 2750m and considering the average slop at such altitudes in greenland those 250m can cover a huge area for sure and the 500m would cover an even larger area that could account for almost half the area where it is snowing.

Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 30, 2019, 05:34:25 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 29 July 2019

On this day...

Melt up a bit
Precipitation**high, all in the SE quadrant, overwhelming slightly higher melt and as a result
SMB (Surface Mass Balance) LOSS"" much below average.

""EDIT - added the missing word "LOSS"

**GFS showing most precipitation as snow.
_______________________________________________
See next post for next 3 days
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 30, 2019, 05:42:49 AM
http://polarportal.dk/en/greenland/surface-conditions/ Prospects 29 July to Aug 01 2019

GFS Outlook

Precipitation 3 day outlook. Greenland North & West very dry. Precipitation, that could be high, pushing in from the Atlantic towards the east coast - looking like rain at lower altitudes. But still shown as mostly snow.

After 3 days precipitation in the SE quadrant reduces.

Does GFS take high temperatures into account sufficiently ?

Melt / Temperatures.
Spike in temperatures reaching extreme highs on Tuesday (i.e. today) & still very strong Wednesday.
Much above average Thursday and then moderating day by day. Nearly all of Greenland will get some melt at some time over the next 3 days - and in some low altitude places extreme melt for long periods.

It will be interesting to see how much the higher precipitation offsets the higher melt in the SMB gain / loss equation. And how does the DMI model deal with precipitation falling as rain in lower altitudes?
_______________________________________________

High pressure has been, is, and will be stuck over Greenland until ....("sticky weather")?
Part of a major weather change in the whole Arctic Basin?
Title: Re: Greenland 2019 Melt Season
Post by: HapHazard on July 30, 2019, 08:30:45 AM
To be honest, in this case I don't care much about theories because i spent 50 years in places where the temperatures hovered often if not mostly between zero and 5C once westerly winds braught precipitation.

During this entire period I carefully studied the temperatures related to the kind of precipitation
and in case of snowfall it's quality, flake-size etc.

Result is what I wrote above, it mostly snows till 2C and can snow till 4C. Or in other words, I don't remember snowfall above 5C but I do remember snowfall between 2-4C.

Why does it matter?

Because roughly 100m account for 1C (roughly and generally speaking) and if the freezing temps are around 3000m that makes it snowing down to 2500m if conditions are right but certainly down to 2750m and considering the average slop at such altitudes in Greenland those 250m can cover a huge area for sure and the 500m would cover an even larger area that could account for almost half the area where it is snowing.
All of this correlates with my experience living in the mountains, but I feel like I should throw this out there as an addendum (and to be scrutinized either way)... such precipitation does indeed fall as snow in these conditions, but it doesn't necessarily accumulate. More often than not (IME) it melts as it hits the ground, or very shortly thereafter.

?
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on July 30, 2019, 10:48:44 AM
In this case however the ground is ice...
Title: Re: Greenland 2019 Melt Season
Post by: HapHazard on July 30, 2019, 05:51:18 PM
Yep, that's just it. I've seen it go both ways and normally it's more dependent on wind.
Title: Re: Greenland 2019 Melt Season
Post by: Frivolousz21 on July 30, 2019, 05:59:08 PM
The summit on the 12Z sounding was -0.7C.

Might go above freezing today.
Title: Re: Greenland 2019 Melt Season
Post by: Frivolousz21 on July 30, 2019, 06:06:55 PM
The surface of GIS being rocked.

Title: Re: Greenland 2019 Melt Season
Post by: philopek on July 30, 2019, 09:30:34 PM
To be honest, in this case I don't care much about theories because i spent 50 years in places where the temperatures hovered often if not mostly between zero and 5C once westerly winds braught precipitation.

During this entire period I carefully studied the temperatures related to the kind of precipitation
and in case of snowfall it's quality, flake-size etc.

Result is what I wrote above, it mostly snows till 2C and can snow till 4C. Or in other words, I don't remember snowfall above 5C but I do remember snowfall between 2-4C.

Why does it matter?

Because roughly 100m account for 1C (roughly and generally speaking) and if the freezing temps are around 3000m that makes it snowing down to 2500m if conditions are right but certainly down to 2750m and considering the average slop at such altitudes in Greenland those 250m can cover a huge area for sure and the 500m would cover an even larger area that could account for almost half the area where it is snowing.
All of this correlates with my experience living in the mountains, but I feel like I should throw this out there as an addendum (and to be scrutinized either way)... such precipitation does indeed fall as snow in these conditions, but it doesn't necessarily accumulate. More often than not (IME) it melts as it hits the ground, or very shortly thereafter.

?

Sure, but probably not when it snows on ice ?

I share your observation on streets and on already growing grass in spring but not on snow and over frozen ground with flat brown grass.

Whatever the details, I think we were looking at the exactly same thing. Where I was living altitude was between 500 and 900m above sea-level. In lower areas where the bottom is less deep or not at all frozen, that may differ again.
Title: Re: Greenland 2019 Melt Season
Post by: grixm on July 30, 2019, 09:59:39 PM
More melt ponds than any other day in the season so far at the Freya glacier webcam. 13.6C
 
https://www.foto-webcam.eu/webcam/freya1/
Title: Re: Greenland 2019 Melt Season
Post by: JayW on July 31, 2019, 12:36:20 AM
10 hour loop, band M8.
Click to run
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=2&im=18&ts=1&st=0&et=0&speed=130&motion=loop&map=0&lat=0&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_m08&x=20702&y=13820
Title: Re: Greenland 2019 Melt Season
Post by: HapHazard on July 31, 2019, 03:01:43 AM
Sure, but probably not when it snows on ice ?

I share your observation on streets and on already growing grass in spring but not on snow and over frozen ground with flat brown grass.

Whatever the details, I think we were looking at the exactly same thing. Where I was living altitude was between 500 and 900m above sea-level. In lower areas where the bottom is less deep or not at all frozen, that may differ again.

I'm just musing, mostly. I've lived at 1400m above sea level for 12 years now, and although I often enough observe snowfall melting on ice during above-freezing days, this ain't Greenland.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 31, 2019, 08:55:05 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 30 July 2019

On this day...

Melt a new maximum for the year by a substantial anount- but not quite as high as I thought it would be.

Precipitation high again, all in the SE quadrant, partially counteracting very high melt and as a result
SMB (Surface Mass Balance) LOSS"" much above average, but not spectacularly so.
______________________________________________________
GFS Outlook

Melt / Temperatures.
Spike in temperatures reaching another extreme high today (Wenesday 31 July)

Much above average Thursday and then moderating day by day.

Precipitation 3 day outlook.
Today (Wednesday)  another day of significant precipitation confined to the SE quadrant.

But after that all of Greenland looking very dry or bone dry for at least a week. This could mean that SMB loss will be higher than July 30 & July 31 as lower melt more than offset by no precipitation.

It will be interesting to see how much the higher precipitation offsets the higher melt in the SMB gain / loss equation on this day.

And how does the DMI model deal with precipitation falling as rain in lower altitudes? How much does the model see it as being retained, and how much as runoff to the ocean?
_______________________________________________

High pressure has been, is, and will be stuck over Greenland until ....
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on July 31, 2019, 09:04:29 AM
Albedo and accumulated SMB anomaly maps attached.

It has been definitely a melting season..
Title: Re: Greenland 2019 Melt Season
Post by: Frivolousz21 on July 31, 2019, 12:47:09 PM
The model showed snow over SE GIS where a promice Station reported temperatures of 5.42C.


A little off.

Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on July 31, 2019, 05:57:45 PM
Regardless of moderating temperatures, the recent widespread melt should have lowered albedo across much of the ice sheet. If it stays sunny we should continue to see high melt.
Title: Re: Greenland 2019 Melt Season
Post by: Thomas Barlow on July 31, 2019, 06:02:26 PM
"On the northwestern Greenland ice sheet, 2019 melt to-date is 1.2x that of the previous record melt in 2012." - Jason Box.
-- Programme for monitoring of the Greenland ice sheet - Promice.

https://www.facebook.com/PromiceGL/posts/2375372692725444

http://promice.org/home.html?fbclid=IwAR2fIm4hPSZvZtD7yiGkw0dsaS3mUMetWoBBSPpBm4z0PNQJ0qAGLMNdvjk
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on July 31, 2019, 06:09:42 PM
"On the northwestern Greenland ice sheet, 2019 melt to-date is 1.2x that of the previous record melt in 2012." - Jason Box.
-- Programme for monitoring of the Greenland ice sheet - Promice.

https://www.facebook.com/PromiceGL/posts/2375372692725444

http://promice.org/home.html?fbclid=IwAR2fIm4hPSZvZtD7yiGkw0dsaS3mUMetWoBBSPpBm4z0PNQJ0qAGLMNdvjk

Thank you for that information!!!
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on July 31, 2019, 06:11:33 PM
Webcam at Freya Gletscher (alt. 1053 m above sea level) shows 15.2°C today. Of course I do not know whether this T measurement can stand quality standards of meteorology, but it must be pretty warm up there - also visible in even more melt ponds.
https://www.foto-webcam.eu/webcam/freya1/
Title: Re: Greenland 2019 Melt Season
Post by: Csnavywx on July 31, 2019, 06:51:38 PM
The summit on the 12Z sounding was -0.7C.

Might go above freezing today.

Willing to bet, after looking at Bufkit and other soundings, that there was no snow anywhere on the sheet yesterday. 700mb temps shot above 0C, up to +5 in the east. Hence the very high surface temps even with melting ice and snow. Any mass gain is due to rain and meltwater percolating into the firn. Firn storage isn't infinite though. Several bad melt years are enough to saturate it and cause increasing ponding and runoff. Not to mention the deleterious effect on albedo. Summit never used to reach freezing except once in a lifetime. Now it does so every other year, sometimes more.
Title: Re: Greenland 2019 Melt Season
Post by: SteveMDFP on July 31, 2019, 07:37:35 PM
10 hour loop, band M8.
Click to run

Wow.  Just 10 hours?  A huge fraction of all Greenland showing new melt before our eyes.
Title: Re: Greenland 2019 Melt Season
Post by: Csnavywx on July 31, 2019, 08:11:44 PM
To be honest, in this case I don't care much about theories because i spent 50 years in places where the temperatures hovered often if not mostly between zero and 5C once westerly winds braught precipitation.

During this entire period I carefully studied the temperatures related to the kind of precipitation
and in case of snowfall it's quality, flake-size etc.

Result is what I wrote above, it mostly snows till 2C and can snow till 4C. Or in other words, I don't remember snowfall above 5C but I do remember snowfall between 2-4C.

Why does it matter?

Because roughly 100m account for 1C (roughly and generally speaking) and if the freezing temps are around 3000m that makes it snowing down to 2500m if conditions are right but certainly down to 2750m and considering the average slop at such altitudes in Greenland those 250m can cover a huge area for sure and the 500m would cover an even larger area that could account for almost half the area where it is snowing.
All of this correlates with my experience living in the mountains, but I feel like I should throw this out there as an addendum (and to be scrutinized either way)... such precipitation does indeed fall as snow in these conditions, but it doesn't necessarily accumulate. More often than not (IME) it melts as it hits the ground, or very shortly thereafter.

?

Sure, but probably not when it snows on ice ?

I share your observation on streets and on already growing grass in spring but not on snow and over frozen ground with flat brown grass.

Whatever the details, I think we were looking at the exactly same thing. Where I was living altitude was between 500 and 900m above sea-level. In lower areas where the bottom is less deep or not at all frozen, that may differ again.
`

Again, the situation he describes is diabatically-driven localized cooling in the boundary layer. It requires colder air aloft and steep lapse rates in the boundary layer (near dry adiabatic) with a dry sub-cloud layer. In that situation, precipitation can fall through an above freezing layer and survive via evaporational cooling as it falls to the ground. That doesn't happen in a saturated warm layer aloft once the max T in the layer exceeds ~1C and an aggregate depth past about 400m (depending somewhat on precip rates).

On an ice surface, once the temperature rises above freezing due to advection of a warm air mass over the area, a near surface inversion begins to set up due to melting, which it did, across almost the entire ice sheet. This causes a warm "wedge" to form aloft. Using surface temps to determine precip type then is not advisable:



Title: Re: Greenland 2019 Melt Season
Post by: grixm on July 31, 2019, 08:20:14 PM
New high for the season in NSIDC melt extent too.
Title: Re: Greenland 2019 Melt Season
Post by: Csnavywx on July 31, 2019, 08:21:29 PM
That sounding was from the southeast coast during the precip event there last night.

As you can see, despite the surface temperature being ~3C, the air aloft is *much* warmer and lapse rates are very weak due to advection driven processes (in fact, nearly isothermal to 800mb). The freezing level is up around 750-700mb with a deep warm layer below that.

This was while precip was falling, so I can virtually guarantee almost none of that precip that hit the ice sheet was snow, even with adiabatic cooling from upslope flow and diabatic cooling from precip. melting. There's too much warm advection here. You'd have to go up above 2500m to get it and that might be generous since this was the coolest sounding I could find.

While I do appreciate long personal observational experience, I'm an operational meteorologist by both trade and hobby, so my earlier comments weren't made solely from theory.
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on July 31, 2019, 08:32:49 PM
Than you very much for the professional input Csnavywx
Title: Re: Greenland 2019 Melt Season
Post by: Csnavywx on July 31, 2019, 08:34:17 PM
Just some incredible skew-ts. A few others with freeze levels above 4000m.

This is a subtropical airmass. I've found myself saying this a few times over the past couple of years, but this doesn't belong north of the Arctic circle -- virtually ever.
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on July 31, 2019, 08:38:08 PM
That means a lot of water runoff
Title: Re: Greenland 2019 Melt Season
Post by: Csnavywx on July 31, 2019, 08:52:29 PM
That means a lot of water runoff

Probably quite a bit. Would be interesting to see stream gages there.

Some of this I'm sure is just soaking into firn air-space below the (melting) snow layer, where it can do damage later by slowly saturating it, pooling and partially re-freezing on top and forming hard, clear ice layers and slabs. While these big melt events are spectacular, from the research and observations I've seen recently, I'm beginning to think that the real damage is all of the preconditioning these are doing to the pack for future years. A future Greenland will see these happen very frequently and with bigger magnitude, except with little firn space remaining to soak up runoff and little to buffer albedo drops in the spring.

It's going to make 2012 and this year look like "the good old days".
Title: Re: Greenland 2019 Melt Season
Post by: RoxTheGeologist on July 31, 2019, 10:03:30 PM

It's looking VERY blue in NE Greenland
Title: Re: Greenland 2019 Melt Season
Post by: RoxTheGeologist on July 31, 2019, 10:06:31 PM
Just some incredible skew-ts. A few others with freeze levels above 4000m.

This is a subtropical airmass. I've found myself saying this a few times over the past couple of years, but this doesn't belong north of the Arctic circle -- virtually ever.

Thank you for your professional and, therefore, even more terrifying analysis.
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on July 31, 2019, 10:13:45 PM
Just some incredible skew-ts. A few others with freeze levels above 4000m.

This is a subtropical airmass. I've found myself saying this a few times over the past couple of years, but this doesn't belong north of the Arctic circle -- virtually ever.
Straight from Africa...
Title: Re: Greenland 2019 Melt Season
Post by: HapHazard on July 31, 2019, 10:25:46 PM
Than you very much for the professional input Csnavywx
Indeed! I'm always eager to learn here.
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 01, 2019, 03:52:42 AM
Dr. Robert Rohde is the lead scientist at Berkeley Earth. This is pretty interesting (and worrisome):
Title: Re: Greenland 2019 Melt Season
Post by: Coffee Drinker on August 01, 2019, 05:00:25 AM
Webcam at Freya Gletscher (alt. 1053 m above sea level) shows 15.2°C today. Of course I do not know whether this T measurement can stand quality standards of meteorology, but it must be pretty warm up there - also visible in even more melt ponds.
https://www.foto-webcam.eu/webcam/freya1/

For comparison the same date in 2016 and 2017. 2018 is missing. I would say we have not yet reached the 2016 melt extend but certainly worse than 2017.

2016
https://www.foto-webcam.eu/webcam/freya1/2016/08/01/1200

2017
https://www.foto-webcam.eu/webcam/freya1/2017/08/01/1200
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 01, 2019, 09:36:51 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 31 July 2019

On this day...

Melt a new maximum for the year by a substantial amount.

Precipitation not as high as the last 2 days, all in the SE quadrant, partially counteracting very high melt and as a result
SMB (Surface Mass Balance) loss spectacularly above average.
______________________________________________________
GFS Outlook

Melt / Temperatures. are looking much above average for the next few days.

Precipitation 5 day outlook.
All of Greenland looking very dry or bone dry. This could mean that SMB loss will be as high as July 30 & July 31 as lower melt more than offset by no precipitation.

It will be interesting to see how much the lower precipitation offsets the lower melt in the SMB gain / loss equation over the next few days.

High pressure has been, is, and will be stuck over Greenland until ....
_______________________________________________

Lots of question marks in the posts from the professionals on how the DMI model is dealing with precipitation and melting during this unusual temperature spike. I wonder if the model's parameters can properly deal with events so far outside "normal" limits.
_________________________________________________________________
Most of the time it is very quiet on this thread - but at the moment..........
Mind you, I still say that it is the persistently above average or very much above average melt since June 10 that is more significant for the overall SMB this year than a two / three day event such as this.

My evidence is the melting graph and the SMB graph.
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 01, 2019, 11:17:11 AM
Well, well, the heatwave has a bite...
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 01, 2019, 12:06:31 PM
Just one month to go to the official end of the 2018-2019 Greenland Snowfall, Melt and SMB year.
Mind you, one of these years (not so far away) the climate is going to tell DMI - What do you know?

So far SMB gain for the year nearly 100 GT less than normal, but not in the same league as 2012.
My guess is for a another 50GT or so of SMB loss to go.

I also attach a gif of July melt maps (most days are there). Click to start, runs 4 times and stops (I think).
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 01, 2019, 12:25:32 PM
Nice
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on August 01, 2019, 02:50:36 PM
I think the 50 GT of future melt is a bit low.  I would say between 100 and 125 for the remainder of the year.
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on August 01, 2019, 02:54:11 PM
To clarify my last post a bit.  Last daily SMB was 10 GT loss.   The forecast for the next 3-5 days looks like we will be in a similar SMB loss. 

If we lose 10 GT per day for the next 3-5 days, that is 30 - 50 GT, with several weeks left in the season.

If "only" lose 8 GT in the same period, we will lose 24 - 40 GT, again with several weeks left in the season
Title: Re: Greenland 2019 Melt Season
Post by: Yuha on August 01, 2019, 03:06:08 PM
So far SMB gain for the year nearly 100 GT less than normal, but not in the same league as 2012.
My guess is for a another 50GT or so of SMB loss to go.

To put these numbers into context, the 2012 SMB anomaly of about 330 GT corresponds to a bit under 1 mm of sea level rise.
Title: Re: Greenland 2019 Melt Season
Post by: vox_mundi on August 01, 2019, 11:10:40 PM
Walloped by Heat Wave, Greenland Sees Massive Ice Melt
https://phys.org/news/2019-08-walloped-greenland-massive-ice.html

- The area of the Greenland ice sheet that is showing indications of melt has been growing daily, and hit a record 56.5% for this year on Wednesday

- More than 10 billion tons (11 billion U.S. tons) of ice was lost to the oceans by surface melt on Wednesday alone, creating a net mass ice loss of some 197 billion tons (217 billion U.S. tons) from Greenland in July

- long-term forecast is for continuing warm and sunny weather in Greenland

- since June 1—roughly the start of the ice-loss season—the Greenland ice sheet has lost 240 gigatons (240 billion metric tons) this year. That compares with 290 gigatons lost overall in the 2012 melt season, which usually goes through the end of August.
Title: Re: Greenland 2019 Melt Season
Post by: Tom_Mazanec on August 02, 2019, 01:54:28 AM
Greenland melting in heat wave:
https://wqad.com/2019/07/31/greenland-is-melting-in-a-heatwave-thats-everyones-problem/
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 02, 2019, 08:15:46 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 01 August 2019

On this day...

Melt a new maximum for the year for a second day.

Precipitation low, as a result
SMB (Surface Mass Balance) loss even more spectacularly above average. 11 GT mass loss on this day.
______________________________________________________
GFS Outlook

Melt / Temperatures. are still looking above average for the next few days. Will the current maximum melt be maintained? I suspect a gradual lowering is on the cards.

Precipitation 5 day outlook.
All of Greenland looking very dry or bone dry. This should mean that SMB loss will still be high as as lower melt is offset by very low precipitation.

It will be interesting to see how much the lower precipitation offsets the lower melt in the SMB gain / loss equation over the next few days.

High pressure has been, is, and will be stuck over Greenland until ....
_______________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: Klondike Kat on August 02, 2019, 01:06:22 PM
Wow!  That was a big jump.
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 02, 2019, 01:10:58 PM
Wow!  That was a big jump.

Hope there is a bottom..
Title: Re: Greenland 2019 Melt Season
Post by: Ajpope85 on August 02, 2019, 03:15:14 PM
A video of meltwater runoff under the Kangerlussiauq bridge.

https://mobile.twitter.com/Laurie_Garrett/status/1157015875276464129
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 02, 2019, 03:27:25 PM
Wow
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 03, 2019, 02:56:01 AM
Greenland Ice Sheet Beats All-Time 1-Day Melt Record - Eos

https://eos.org/articles/greenland-ice-sheet-beats-all-time-1-day-melt-record
Title: Re: Greenland 2019 Melt Season
Post by: Sigmetnow on August 03, 2019, 02:58:55 AM
Quote
In the midst of one of the biggest melt events for the Greenland ice sheet, the ice melt on 1 August 2019 was the highest volume ever recorded in a single day.

Air temperatures rose to 10°C above average in places in Greenland this week and peaked above the freezing point for hours at a time at the ice sheet’s summit more than 3,200 meters above sea level. The months of April, May, June, and July also had higher than average temperatures in Greenland. ...
[/quote]https://eos.org/articles/greenland-ice-sheet-beats-all-time-1-day-melt-record
Title: Re: Greenland 2019 Melt Season
Post by: petm on August 03, 2019, 03:04:55 AM
If my arithmetic is right, that's approx. equivalent to 50 Niagra Falls' (for a day).
Title: Re: Greenland 2019 Melt Season
Post by: Viggy on August 03, 2019, 03:57:00 AM
Looks like we are about to lose another 10+ billion tons of water today too ...
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 03, 2019, 04:02:23 AM
What was the maximum melt extent in 2012?
Title: Re: Greenland 2019 Melt Season
Post by: Renerpho on August 03, 2019, 04:08:02 AM
What was the maximum melt extent in 2012?
Here is a direct comparison: https://nsidc.org/greenland-today/greenland-surface-melt-extent-interactive-chart/ (https://nsidc.org/greenland-today/greenland-surface-melt-extent-interactive-chart/)
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 03, 2019, 04:12:03 AM
Thank you!! 2019 is exceptional 2nd to 2012 in more ways than one...
Title: Re: Greenland 2019 Melt Season
Post by: Renerpho on August 03, 2019, 04:20:04 AM
This ~4,200 km² piece of ice has resisted the ongoing breakup in that region for quite a while now. The last couple of days have seen that region deteriorate rapidly. I wonder if that piece will stay intact after it becomes loose? My guess is it won't (stay intact), but how quickly will it melt?

https://worldview.earthdata.nasa.gov/?v=394342.4,-1124787.2000000002,787558.4,-945331.2000000002&p=arctic&t=2019-08-02-T18%3A00%3A00Z (https://worldview.earthdata.nasa.gov/?v=394342.4,-1124787.2000000002,787558.4,-945331.2000000002&p=arctic&t=2019-08-02-T18%3A00%3A00Z)
(https://i.imgur.com/lN0waIT.png)
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 03, 2019, 04:27:05 AM
The NSIDC chart that Renerpho linked compares the melting extent between 2012 and 2019 over the ice sheet.  The purported record is volume lost which is different, and more important if true. 

AGU’s Eos is usually a pretty reliable source.  However, Ruth Mottram will have the final say based upon the DMI data. 

She knocked off for the weekend about four hours ago saying that her mentions were exploding on Twitter, and implying she needed a break.

We will need to wait and see if she verifies these numbers on Monday.

In any event, it has been a very remarkable few days of melting.   
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 03, 2019, 04:34:07 AM
This ~4,200 km² piece of ice has resisted the ongoing breakup in that region for quite a while now.

That same piece seems to show up year after year.  It must be caused by some unique bathymetry in that area. But that is sea ice, and not related to the ice sheet melting described in the figures and charts above. 
Title: Re: Greenland 2019 Melt Season
Post by: Renerpho on August 03, 2019, 04:38:34 AM
The NSIDC chart that Renerpho linked compares the melting extent between 2012 and 2019 over the ice sheet.  The purported record is volume lost which is different, and more important if true.

Yes. I can only give extent (or area, whatever the difference might be in this context), no 3rd dimension. At least it answers DrTskoul's question, I hope. As mentioned in the article, while there have been days of greater melting extent, volume apparently hit a record.
I can't find a similar resource (graph, table, ...) for volume. If anyone has that data in whatever form, I'd very much like to see it!

That same piece seems to show up year after year.  It must be caused by some unique bathymetry in that area. But that is sea ice, and not related to the ice sheet melting described in the figures and charts above.
Yes, my question was only loosely related, sorry. I will scroll through Worldview of recent years to see what happened to it before.  :)

EDIT: It stays in place year after year. If it melts then it melts in place. The bathymetric map shows the sea is shallow in that region. I guess it is attached to the sea floor.
(https://www.gebco.net/news_and_media/images/ne_greenland.jpg)
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 03, 2019, 04:44:04 AM
I asked about extent, the easy part. Volume is another story ..
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 03, 2019, 04:47:57 AM
I certainly did not mean to be rude Renerpho, and I am sorry if it came off that way. 

Your post was on point and answers DrTskoul’s question.  I was just pointing out the possible new record is something different. 

Dr. Mottram is a scientist with DMI.  She is pretty much the most authoritative figure on Greenland ice sheet melt of anyone who regularly comments on it.  I would accept DMI’s data over NSIDC when it comes to the Greenland ice sheet. 

I’m not sure how they calculate volume, but they have a way.  I don’t doubt the information in the article from AGU Eos, but I will wait until it is verified from other scientists. 
Title: Re: Greenland 2019 Melt Season
Post by: Renerpho on August 03, 2019, 04:53:38 AM
I certainly did not mean to be rude Renerpho, and I am sorry if it came off that way.
No offense taken, Rod!  :)

I am quite sure their data is accurate. I am still curious about, for example, what the old record was, when it was established, etc. But it's not like this was super important to me, so unless you know where I get it, don't spend too much time on finding it.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 03, 2019, 07:44:59 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 02 August 2019

On this day...

Melt slightly below yesterday's new maximum for the year at nearly 60% of land area.

Precipitation almost zero, and as a result

SMB (Surface Mass Balance) still spectacularly above average. About 10 GT mass loss from melting on this day.
______________________________________________________
GFS Outlook

Melt / Temperatures. are still looking above average for the next few days. I suspect a gradual lowering of daily melt is on the cards.

Precipitation 5 day outlook.
All of Greenland still looking very dry or bone dry. This should mean that SMB loss will still be high as as lower melt is offset by very low precipitation.

It will be interesting to see how much the lower precipitation offsets the lower melt in the SMB gain / loss equation over the next few days.

High pressure has been, is, and will be stuck over Greenland until ....
_______________________________________________
Quote from DMI
Quote
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.
Title: Re: Greenland 2019 Melt Season
Post by: Simon on August 03, 2019, 09:08:42 AM
Although the vast ice sheet actually gains ice over the year, there is a net loss of ice mass through an accelerating glacier loss as demonstrated by this thorough review.

https://www.pnas.org/content/116/19/9239

Greenland has been causing a sea level rise of 0.3mm a year. I just wonder what this value is going to increase to in the coming decades?

Title: Re: Greenland 2019 Melt Season
Post by: oren on August 03, 2019, 10:32:07 AM
If my arithmetic is right, that's approx. equivalent to 50 Niagra Falls' (for a day).
12.5 billion tons per day, a ton is a cubic meter, a day is 24x60x60 seconds, so this comes out to an amazing 145,000 cubic meters/second, or about 0.145 Sverdrup, equivalent to 8.5 Mississippi rivers, or about 0.7 Amazon rivers. These are very serious numbers.
I should point out SMB is not directly comparable to river discharge, as it includes precipitation on the one hand and evaporation/sublimation on the other. But I think both of these figures were much smaller than meltwater runoff on this specific day.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on August 03, 2019, 02:09:21 PM
Although the vast ice sheet actually gains ice over the year, there is a net loss of ice mass through an accelerating glacier loss as demonstrated by this thorough review.

https://www.pnas.org/content/116/19/9239

Greenland has been causing a sea level rise of 0.3mm a year. I just wonder what this value is going to increase to in the coming decades?

The thing I would be worrying about is the acceleration of melt trends. So many of the metrics tracking AGW and its impacts behave this way. Not sure I am seeing it with Greenland mass loss here although the chart tracks far too few years to simply eyeball it. Does anyone measure the growth rate in Greenland mass loss?
Title: Re: Greenland 2019 Melt Season
Post by: J Cartmill on August 03, 2019, 04:41:52 PM
Several great photos here:

https://www.buzzfeednews.com/article/gabrielsanchez/greenland-ice-melt-climate-change-warming-arctic (https://www.buzzfeednews.com/article/gabrielsanchez/greenland-ice-melt-climate-change-warming-arctic)
Title: Re: Greenland 2019 Melt Season
Post by: P-maker on August 03, 2019, 06:23:47 PM
Having spent part of my youth on the margins of the Greenland Ice Sheet (GrIS) during the early 80'ies, I can certainly testify that this year's melt is extra-ordinary. Had we known at that time that melt lakes, crevasses, moulins and the like were as ubiquitous as we see today, we would never have been allowed anywhere near those local danger zones.

In my deepest soul, I am genuinely shocked that this kind of media/Twitter hysteria goes on for days without even the slightest bit of reflection. I know that out there, we have seasoned observers of Arctic reality 10, 20, even 60 years ago. None of those guys are allowed to chip in at the current pace of posting. It's about time to reflect a bit and consider what we have let ourselves into.

Please cool down for a minute and let the old folks contribute. This might add some perspective instead of more details, numbers and noise.

Cheers P

Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 03, 2019, 07:07:08 PM
Does anyone measure the growth rate in Greenland mass loss?
Many many people do.

Google "GRACE-FO" & search "GRACE-FO" on this forum

GRACE-FO Data just started up again (up to May 2019). See example showing big variation between basins.

Will no doubt be part of Greenland Melt year-end (end is Aug 31 i.e. this month) reports later this yr (NSIDC & DMI).
GRACE-FO monthly data should be out up to August by end September.

But by golly I wish we had access to DMI monthly temp and precipitation data by drainage basins and SMB by drainage basins. That would be an impressive data set to analyse.

I've only got precip and temp data by months to end 2016 for all Greenland- from World Bank of all places.
________________________________________________
And now a whinge.
I have posted all I know about this on this thread, What's New in Greenland, and in Satellite News for months. Sometimes I think, "Why bloody bother".
__________________________________________
ps:
I agree with P-maker, quote below.
The world  -and a good few scientists - have leapt upon this three day shocker, and is already looking for the next big thing. I have been going on and on for what seems ages about it is the length of this event - since June 10th - that matters most.

I agree with P-maker, quote below, who expresses my similar feelings much better than I can
Quote
In my deepest soul, I am genuinely shocked that this kind of media/Twitter hysteria goes on for days without even the slightest bit of reflection. I know that out there, we have seasoned observers of Arctic reality 10, 20, even 60 years ago. None of those guys are allowed to chip in at the current pace of posting. It's about time to reflect a bit and consider what we have let ourselves into.

Please cool down for a minute and let the old folks contribute. This might add some perspective instead of more details, numbers and noise.

Cheers P
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 03, 2019, 07:19:12 PM
Shock news and sound bytes at social media. Isn't the mode of news information of the current generation? If it ain't on Twitter and Instagram it ain't news?

Keep up the good work gero and thanks for the comments P
Title: Re: Greenland 2019 Melt Season
Post by: vox_mundi on August 03, 2019, 11:48:22 PM
This Satellite Image Shows Everything Wrong With Greenland Right Now
https://earther.gizmodo.com/this-satellite-image-shows-everything-wrong-with-greenl-1836919989

If you could sum up climate change’s impact on the Arctic in one image, you’d be hard pressed to find something better than this satellite view, which shows the meltdown of one of the largest stores of ice on Earth while a wildfire rages in the distance.

(https://i.kinja-img.com/gawker-media/image/upload/s--i95YFTo2--/c_fit,dpr_3.0,f_auto,fl_progressive,q_80,w_636/ukorqhytcmpmns2r28yw.jpg)

(https://i.kinja-img.com/gawker-media/image/upload/xc66nr3r8ixz6vs2cvv2.gif)
A portion of the Greenland ice sheet with four images blended from July 15-30. The white snow melts exposing blue ice underneath.

--------------------

Rather than think, "Why bloody bother"; consider that your efforts have borne fruit.

The chronicler is one of the more important yet unsung pieces in history.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 04, 2019, 06:36:21 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 03 August 2019

On this day...

Melt a bit below yesterday's..

Precipitation almost zero, and as a result

SMB (Surface Mass Balance) loss still double the average. About 8 GT mass loss from melting on this day.
______________________________________________________
GFS Outlook

Melt / Temperatures. are still looking above average for the next few days. I suspect a gradual lowering of daily melt will continue.

Precipitation 5 day outlook.
All of Greenland still looking very dry or bone dry. This should mean that SMB loss will still be well above average as lower melt is offset by very low precipitation.

High pressure has been, is, and will be stuck over Greenland until ....
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
Title: Re: Greenland 2019 Melt Season
Post by: Shared Humanity on August 04, 2019, 04:18:39 PM
Mass loss is less than prior days. The twitterverse will quiet and Greenland melt will cease to entertain 21st century humanity.
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 05, 2019, 02:38:26 AM
Dr. Mottram has spoken and she did not dispute the volume numbers. I expect that this week we will get more info from her and Professor Box about what they think it means. 

I am surprised by the pushback on information from Twitter.  That is where the scientists speak.

It is nice that Gerontocrat copies and pastes the DMI graphs here each day, but what the scientists in charge of interpreting that data say is much more important than his speculation. 

This was apparent when Shared Humanity indicated that he did not understand they track mass gain.  That feature is inherent in the charts Gerontocrat posts. 

If you guys don’t want any more info from Twitter, then I will stop posting it.   But you are about 10 years behind technology if you don’t understand how important that platform is. 
Title: Re: Greenland 2019 Melt Season
Post by: oren on August 05, 2019, 02:47:50 AM
A. I prefer info from any source I can get it, be it twitter or DMI, as long as it is accurate
B. I am happy that there is a mini-twitterstorm over Greenland melt. Even if it dies down after a few days, many people will remember it.
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 05, 2019, 03:04:41 AM
I don’t like sound bites, too easy. Prefer deep analysis, cannot do with tweets...
Title: Re: Greenland 2019 Melt Season
Post by: petm on August 05, 2019, 03:05:56 AM
Please do keep posting Twitter. Yes, it has a lot of crap on it (like everything these days and probably always), but it has also become a standard method of scientific communication, perfectly suited for real-time occurrences including natural events (Greenland melt) and new publications, etc (announcements about Greenland melt). Perhaps not everyone has yet become aware of its utility.
Title: Re: Greenland 2019 Melt Season
Post by: Frivolousz21 on August 05, 2019, 04:23:23 AM
Please post Umizoomi new sources as you guys can anything from Twitter that comes from professor box is invaluable
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 05, 2019, 04:27:30 AM
Jason Box back in May: How we already know 2019 will be a big melt year for Greenland

https://t.co/s5mjmqxmf3
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 05, 2019, 04:40:48 AM
Friv is just being a smart ass.  His forecasts never turn out like he thinks they will, and he does not like to be confronted with real scientists.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 05, 2019, 11:57:29 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 04 August 2019

On this day...

Melt a bit below yesterday's and still miles above average..

Precipitation almost zero, and as a result

SMB (Surface Mass Balance) loss still double the average. About 7 GT mass loss from melting on this day.

EDIT
Albedo massive change in July - little gif of albedo anomalies attached.  Plays forever.
Remember - red & yellow = darker, blue = lighter (i.e. red & yellow means more melt potential).
______________________________________________________
GFS Outlook

Melt / Temperatures. are still looking above average for the next few days but +ve temp anomalies declining and after day 5 may be -ve over most of Greenland.

Precipitation 5 day outlook.
Gradual increase in precipitation though still looking low. This should mean that SMB loss will still be above average as lowering melt is offset by low precipitation.

High pressure has been, is, and will be stuck over Greenland - until the cows come home**....
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
___________________________________________________________
** scientific input
Title: Re: Greenland 2019 Melt Season
Post by: be cause on August 05, 2019, 01:23:15 PM
pretty rotten gif .. only half greenland and stopped playing before I find what I'm watching . Limiting the number of times your gifs play is really maddening .. by the time I've found out what I'm watching it is often too late .. having to scroll to find title or index or whatever and the gif is done .. b.c.

 were not all nimble fingered youngsters you know .. :)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 05, 2019, 02:48:28 PM
pretty rotten gif .. only half greenland and stopped playing before I find what I'm watching . Limiting the number of times your gifs play is really maddening .. by the time I've found out what I'm watching it is often too late .. having to scroll to find title or index or whatever and the gif is done .. b.c.

 were not all nimble fingered youngsters you know .. :)
I did the three score and ten a while ago.
I think my lap-top did as well.
It went all weird and had to close all down & restart. It does that when too many big spreadsheets and other stuff is in memory. Like me, it easily gets confused.

GIF changed, plays forever with all of of Greenland visible.
Title: Re: Greenland 2019 Melt Season
Post by: oren on August 05, 2019, 03:44:07 PM
Thanks G. In all honesty, I could never figure out the quirk with limiting the number of repetitions. I often find myself staring at a gif several times in a row, focusing each time on a different part. This is even more so when I use my phone. If it stops after a few, I usually need to reload it again, wasting bandwidth and energy.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 05, 2019, 03:47:16 PM
Thanks G. In all honesty, I could never figure out the quirk with limiting the number of repetitions. I often find myself staring at a gif several times in a row, focusing each time on a different part. This is even more so when I use my phone. If it stops after a few, I usually need to reload it again, wasting bandwidth and energy.
It was all because some of the ASIF members have really lousy connections and even lousier limits on download limits.

So one of those things when some are going to be hacked off no matter what you do.
Title: Re: Greenland 2019 Melt Season
Post by: grixm on August 05, 2019, 04:05:49 PM
Thanks G. In all honesty, I could never figure out the quirk with limiting the number of repetitions. I often find myself staring at a gif several times in a row, focusing each time on a different part. This is even more so when I use my phone. If it stops after a few, I usually need to reload it again, wasting bandwidth and energy.
It was all because some of the ASIF members have really lousy connections and even lousier limits on download limits.

So one of those things when some are going to be hacked off no matter what you do.

But how does limiting the number of playbacks help with this? After you've watched the animation one time, you don't have to download it again to watch it again, it can loop forever for free.
Title: Re: Greenland 2019 Melt Season
Post by: oren on August 05, 2019, 04:11:15 PM
But how does limiting the number of playbacks help with this? After you've watched the animation one time, you don't have to download it again to watch it again, it can loop forever for free.
Yes. That's what I meant.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 06, 2019, 08:57:44 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 05 August 2019

On this day...

Melt a bit below yesterday's. Merely exceptionally high..

Precipitation almost zero, and as a result

SMB (Surface Mass Balance) loss still double the average. About 7 GT mass loss from melting on this day.
______________________________________________________
GFS Outlook For once, I am reckless and say for the next 10 days. Why - High Pressure - image attached. This high has been sitting there since I do not know when and looks solid as a rock. This implies, stable, i.e  boring, weather as Greenland's summer dies and transits its incredibly short Autumn towards winter.

Melt / Temperatures. are still looking above average for the next few days as temperatures decline gradually until most of Greenland gets - cold.

Precipitation 5 day outlook.
Gradual increase in precipitation though still looking low. This should mean that SMB loss will still be above average while melt gradually reduces.

High pressure has been, is, and will be stuck over Greenland - until the cows come home**....
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
___________________________________________________________
** scientific input
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 07, 2019, 09:13:41 AM
All quiet on the Greenland melting season thread..

http://polarportal.dk/en/greenland/surface-conditions/ as at 06 August 2019

On this day...

Melt a bit below yesterday's. Merely much above average..

Precipitation low, and as a result ......

SMB (Surface Mass Balance) loss less than yesterday but double the average. About 6 GT mass loss from melting on this day.
______________________________________________________
Melt / Temperatures. a bit above average for the next few days while declining gradually until most of Greenland gets - cold.

Precipitation 5 day outlook.
Still looking low.

This should mean that SMB loss though reducing will still be above average while melt gradually reduces.

High pressure has been, is, and will be stuck over Greenland - until ....?
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 08, 2019, 06:31:19 AM
Temperatures have come down, and we are talking again about albedo.  These are the current maps.  Posted about 12 hours ago. 
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 08, 2019, 06:34:11 AM
There is a new data product Dr. Mottram seems excited about that should be out soon.
Title: Re: Greenland 2019 Melt Season
Post by: Alphabet Hotel on August 08, 2019, 06:55:14 AM
The ice cap (I think that's what this is?) north of the 79N glacier is melting pretty strongly. This is from a few days ago. Note the melt water accumulating around the edges as well as flowing into the channels. These all eventually drain into a big lake.
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 08, 2019, 07:25:03 AM
The ice cap (I think that's what this is?) north of the 79N glacier is melting pretty strongly. This is from a few days ago. Note the melt water accumulating around the edges as well as flowing into the channels. These all eventually drain into a big lake.

Is the whole thing a transparent ice cube ??
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 08, 2019, 08:52:29 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 07 August 2019

On this day...

Melt a tiny bit below yesterday's. Merely much above average..

Precipitation low, and as a result ......

SMB (Surface Mass Balance) loss less than yesterday but double the average. Only 5,000 million tons mass loss from melting on this day.
______________________________________________________
Melt / Temperatures. a bit above average for the next few days while declining gradually until eventually most of Greenland gets - cold.

Precipitation 5 day outlook.
Still looking low.

This should mean that SMB loss though reducing will still be above average while melt gradually reduces.

High pressure has been, is, and will be stuck over Greenland - until ....?

The melting season gently fades into history as the Greenland summer ends, the oh so short Autumn starts and winter arrives with thump.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 08, 2019, 08:55:09 AM
The ice cap (I think that's what this is?) north of the 79N glacier is melting pretty strongly. This is from a few days ago. Note the melt water accumulating around the edges as well as flowing into the channels. These all eventually drain into a big lake.

Is the whole thing a transparent ice cube ??
Only need a very large glass and a very big bottle of gin?
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 08, 2019, 11:42:50 AM
Hear hear...
Title: Re: Greenland 2019 Melt Season
Post by: RoxTheGeologist on August 08, 2019, 06:57:04 PM
Hear hear...

Hmm, I think we better start taking our gin in tea, I don't think the ice is going to be there much longer. Is that too quintessentially British?
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 08, 2019, 07:39:56 PM
Hear hear...

Hmm, I think we better start taking our gin in tea, I don't think the ice is going to be there much longer. Is that too quintessentially British?

Ha... :) I need my tonic
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 09, 2019, 07:33:01 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 07 August 2019

On this day...

Melt below yesterday's. Merely above average..

Precipitation low, and as a result ......

SMB (Surface Mass Balance) loss less than yesterday but double the average. Only 4,000 million tons mass loss from melting on this day.
______________________________________________________
Melt / Temperatures. a bit above average for the next few days while declining gradually until eventually most of Greenland gets - cold.

Precipitation 5 day outlook.
Still looking lowish.

This should mean that SMB loss though reducing will still be above average while melt gradually reduces.

High pressure has been, is, and will be stuck over Greenland - until ....?

The melting season gently fades into history as the Greenland summer ends, the oh so short Autumn starts and winter arrives with thump.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: NotaDenier on August 09, 2019, 01:05:18 PM
The isolated blues on this map near the edges of the GIS, could they be related to the glaciers slumping toward the sea? Meaning an area close to the edge of the ice sheet is suddenly slightly higher because the glacier sped up?

Why else the isolated blues? The big mass of blue down in the SE corner makes sense.
Title: Re: Greenland 2019 Melt Season
Post by: AndyW on August 09, 2019, 03:16:17 PM
Is there a multiyear version of this graph  available ?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.zen141854.zen.co.uk%2Fgrsnap2019.jpg&hash=af6fa85aa637facc15d928dfb66b3983)

It's a big melt season this year, but last two years have been quite the reverse.  It's the equivalent of the the Arctic graphs showing 2012 and this year and the medium.

Andy
Title: Re: Greenland 2019 Melt Season
Post by: mabarnes on August 09, 2019, 04:26:40 PM
The isolated blues on this map near the edges of the GIS, could they be related to the glaciers slumping toward the sea? Meaning an area close to the edge of the ice sheet is suddenly slightly higher because the glacier sped up?

Why else the isolated blues? The big mass of blue down in the SE corner makes sense.

Surface Mass Balance (SMB) = gains - losses ... from the surface.  Basically precipitation gains minus sublimation/ablation losses.  It doesn't include base melt losses or glacial calving losses.

The blue is in those area due to most of the precip hitting the east coast of Greenland this season.  If you look at the Aug 8 (not cumulative) map you can see the blue addition of the latest systems' precipitation in the daily map G posted right before yours.

Attached is is the 3 hour precip from right now (8:20 EST 8/9) showing the remnants of the systems, but you get the idea.  Still, the 8/8 map is red on the SE coast as the precip may have been rain at coastal altitudes, adding to the melt, or if snow, simply was falling on top of still melting melting - didn't "stick" as we used to say as kids.

Hope this helps.  I'm a lurker/newbie mahself so any corrections please and thanks.

Here's a good glossary on the topic:  https://unesdoc.unesco.org/ark:/48223/pf0000192525
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 10, 2019, 03:36:07 AM
Greenland is on track to lose most ice on record this year and has already shed 250 billion tons

From Washingtonpost.com (https://beta.washingtonpost.com/weather/2019/08/08/greenland-is-track-record-melt-year-having-already-lost-billion-tons-ice/?outputType=amp)

Quote
All told, a computer model that tracks ice mass gained or lost by snowfall and snow and ice melt, but does not include the ice mass lost by glaciers which terminate in the ocean waters, found that the ice sheet lost a total of about 55 billion tons through melt runoff during the extreme melt event, which was about 40 billion tons more than the 1981 to 2010 average for the same time period, NSIDC reported.

“The glacier flow system also contributes to loss, and will likely add another 60 to 100 billion tons of loss [as icebergs],” said Ted Scambos, a senior research scientist at the University of Colorado.

According to Scambos, 2012 eventually reached 300 billion tons of surface ice mass loss from Greenland and 2019 may exceed that.
Title: Re: Greenland 2019 Melt Season
Post by: Rod on August 10, 2019, 05:59:37 AM
It is important to remember that SMB is always positive (at least so far).   The losses from the Greenland ice sheet come from other processes such as glacier calving. 

This might change moving forward, but so far, all the ice lost to surface melting in the summer is gained back by snow accumulation. 

Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 10, 2019, 07:57:59 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 09 August 2019

On this day...

Melt below yesterday's. Merely above average..

Precipitation low, and as a result ......

SMB (Surface Mass Balance) loss same as yesterday & double the average. Only 4,000 million tons mass loss from melting on this day.
______________________________________________________
Melt / Temperatures. a bit above average for the next few days while declining gradually until eventually most of Greenland gets - cold.

Precipitation 5 day outlook.
Still looking lowish.

This should mean that SMB loss though reducing will still be above average while melt gradually reduces.

High pressure has been, is, and will be stuck over Greenland - until ....?

The melting season gently fades into history as the Greenland summer ends, the oh so short Autumn starts and winter arrives with thump.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 10, 2019, 08:27:42 AM
Is there a multiyear version of this graph  available ?

Andy
Nope,

BUT you reminded me to follow up a couple of links, and....

There is an open access paper - gold dust, that came out in May 2019:-

https://www.pnas.org/content/116/19/9239
Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018

Attached is a graph EDIT - 2 MORE GRAPHS

I have also downloaded the spreadsheet but that is going to take a bit of time to figure out.

There are also annual reports from e.g.
http://sciencenordic.com/how-greenland-ice-sheet-fared-2018

____________________________________________________________
ps: PNAS published a similar study on Antarctica
https://www.pnas.org/content/116/4/1095
Four decades of Antarctic Ice Sheet mass balance from 1979–2017
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 11, 2019, 12:04:50 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 10 August 2019

On this day...

Melt below yesterday's. Only just above average..

Precipitation very low, and as a result ......

SMB (Surface Mass Balance) loss same as yesterday & double the average. 4,000 million tons mass loss from melting on this day.
______________________________________________________
Melt / Temperatures. Southern  Eastern Greenland gets cold. North & West still above average.

Precipitation 5 day outlook.
Still looking lowish or very dry.

This should mean that though melt is reducing  SMB mass losswill still be above average.

High pressure has been, is, and will be stuck over Greenland - until ....?

The melting season gently fades into history as the Greenland summer ends, the oh so short Autumn starts and winter arrives with thump.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: johnm33 on August 11, 2019, 12:21:17 PM
A look at freshwater discharge. 30 days to 10:08 HYCOM
(https://media.giphy.com/media/J33kRnY63Kp1lN4ULu/giphy.gif)
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 11, 2019, 12:21:42 PM
The attached images show the GFS weather 5 day forecast for Greenland & the surrounding area.

This high pressure and low precipitation (combined with high temperatures) weather pattern seems to have dominated just about the whole summer since mid-June.

But after 5 days just a possibility of some changes around the edges, following the recent change to below average temperatures in Southern Greenland...

Autumn has arrived?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 11, 2019, 12:25:11 PM
A look at freshwater discharge. 30 days to 10:08 HYCOM
I wonder how it compares with previous years? It surely includes water loss from glaciers at the ocean edge so will be even greater than the surface melt shown in the SMB.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 12, 2019, 08:24:18 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 11 August 2019

On this day... almost no change again

Melt a bit below yesterday's. Only a tiny bit above average..

Precipitation very low, and as a result ......

SMB (Surface Mass Balance) loss same as yesterday & double the average. 4,000 million tons mass loss from melting on this day.

Albedo anomaly very high, i.e. darker surface. Any insolation, though reducing quickly, more likely to cause melt.
______________________________________________________
5 day outlook

Melt / Temperatures. Southern & Eastern Greenland cold. North & West still above average.

Precipitation 5 day outlook.
Still looking lowish or very dry.

This should mean that though melt is reducing  SMB mass loss will still be above average.

High pressure has been, is, and will be stuck over Greenland - until ....?

The melting season gently fades into history as the Greenland summer ends, the oh so short Autumn starts and winter arrives with thump.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on August 12, 2019, 10:21:05 PM
Found this over at:

https://nsidc.org/greenland-today/

Shows that 2019 is tracking nearly in step with 2012 for this metric.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 13, 2019, 12:05:39 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 12 August 2019

On this day
... the end-of-season downward gentle slope continues

Melt a bit below yesterday's. At average..

Precipitation low, and as a result ......

SMB (Surface Mass Balance) loss a bit lower than yesterday & still double the average. Just about 4,000 million tons mass loss from melting on this day.
______________________________________________________
5 day outlook

Melt / Temperatures. Southern & Eastern Greenland cold. North & West still above average.

Precipitation 5 day outlook.
Still looking lowish or very dry.

This should mean that though melt is reducing  SMB mass loss will still be above average.

High pressure has been, is, and will be stuck over Greenland - but perhaps reducing its size after a few days.

The melting season gently fades into history as the Greenland summer ends, the oh so short Autumn starts and winter arrives with thump.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 13, 2019, 12:12:02 PM
Found this over at:

https://nsidc.org/greenland-today/

Shows that 2019 is tracking nearly in step with 2012 for this metric.

Different model than DMI - the DMI model showing very high SMB mass loss but still much less than 2012.

Which do I believe?
- Neither.

What do I believe?
- That SMB mass loss was exceptionally high in 2019.
- If I was forced to put a figure on it, I would simply average the 2 models.

What is needed?
- more weather stations on Greenland to test models against field observations.
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on August 13, 2019, 03:01:10 PM
I thought it was interesting that a different model shows a ~150 GT difference from the other....
Title: Re: Greenland 2019 Melt Season
Post by: GoodeWeather on August 13, 2019, 03:46:26 PM
I thought it was interesting that a different model shows a ~150 GT difference from the other....

Not sure if NSIDC uses total mass or just surface mass, as DMI o ly calculates SMB which could be the difference we are looking at.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 13, 2019, 04:17:35 PM
I thought it was interesting that a different model shows a ~150 GT difference from the other....

Not sure if NSIDC uses total mass or just surface mass, as DMI o ly calculates SMB which could be the difference we are looking at.
http://nsidc.org/greenland-today/
Quote
"Our colleague, Xavier Fettweis at the Université of Liège, Belgium, developed a Greenland ice and climate model that provides estimates of mass gained or lost by snowfall and melt (not including ice lost from the outflow of glaciers) (Figure 3a). "

The NSIDC graph is SMB, i.e. excluding calving and loss by melting by sea water of marine terminating glaciers.

The NSIDc shows a loss of about 275 billion tons greater than average, the DMI model more like 175 billion tons greater than the average. Amazingly enough, both models are using a 1981-2010 baseline.
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on August 13, 2019, 10:27:30 PM
As long as the individual models are consistent, it gives us a trend line.

I personally think the model including outflow from glaciers is more indicative of the real world.   Potato, potato...

modified to clarify ...."outflow from" glaciers...
Title: Re: Greenland 2019 Melt Season
Post by: DrTskoul on August 13, 2019, 10:29:34 PM
It includes glaciers...
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 14, 2019, 04:17:48 PM
It includes glaciers...

? ? ?
"Our colleague, Xavier Fettweis at the Université of Liège, Belgium, developed a Greenland ice and climate model that provides estimates of mass gained or lost by snowfall and melt (not including ice lost from the outflow of glaciers) (Figure 3a). "
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 14, 2019, 04:23:28 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 13 August 2019

On this day
... the end-of-season downward gentle slope continues

Melt a bit below yesterday's. At average..

Precipitation low, and as a result ......

SMB (Surface Mass Balance) loss a bit lower than yesterday & still double the average. A bit less than 4,000 million tons mass loss from melting on this day, but still nearly 2 gt more than average.
______________________________________________________
5 day outlook

Melt / Temperatures. Southern & Eastern Greenland cold. A part of the North & West still a bit above average.

Precipitation 5 day outlook.
Still looking lowish or very dry.

This should mean that though melt is reducing, SMB mass loss will still be above average.

High pressure has been, is, and will be stuck over Greenland - but certainly looks like much lower extent and intensity.

The melting season gently fades into history as the Greenland summer has ended(?), the oh so short Autumn starts and winter arrives with thump - very soon (?)
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on August 14, 2019, 10:15:27 PM
Looks like Fram export may start again...
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 15, 2019, 09:43:40 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 14 August 2019

On this day
... the end-of-season downward gentle slope continues

Melt a bit below yesterday's. At just below average..

Precipitation very low, and as a result ......

SMB (Surface Mass Balance) loss the same yesterday & still double the average. A bit less than 4,000 million tons mass loss from melting on this day, but still nearly 2 gt more than average.
______________________________________________________
5 day outlook

Melt / Temperatures. Southern & Eastern Greenland cold. A part of the North & West still a bit above average.

Precipitation 5 day outlook.
Still looking lowish or very dry. But as the Greenland High shrinks and weakens signs of precipitation at both North and South fringes.

This should mean that though melt is reducing, SMB mass loss might still be above average for a few days more.

High pressure has been, is, and will be stuck over Greenland - but certainly looks like continuing to shrink and reduce in pressure.

The melting season now quickens its fade into history as the Greenland summer has ended, the oh so short Autumn has started and winter arrives with thump - very soon - unless something weird happens.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on August 15, 2019, 07:47:17 PM
A few weeks ago (during heat wave) there was a prediction of an additional 50 GT of melt by the end of melt season.    I thought that seems low and predicted 100 to 125 GT.   How many GT have we lost since those posts?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 15, 2019, 09:25:22 PM
A few weeks ago (during heat wave) there was a prediction of an additional 50 GT of melt by the end of melt season.    I thought that seems low and predicted 100 to 125 GT.   How many GT have we lost since those posts?
It was on Aug 1 I said maybe 50GT and you said 100-125 GT
It looks like you were more right than me.

Another 10-20GT to go?

Graph with red lines on attached.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 16, 2019, 08:17:12 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 15 August 2019

On this day
... the end-of-season downward gentle slope continues to accelerate

Melt  below yesterday's. At below average..

Precipitation  not that low, and as a result ......

SMB (Surface Mass Balance) loss less than yesterday . Around 3GT mass loss on this day, but still about 1 gt more than average.
______________________________________________________
5 day outlook

Melt / Temperatures. Southern & Eastern Greenland cold. A part of the North & West still a bit above average.

Precipitation 5 day outlook.
Still looking lowish or very dry. But as the Greenland High shrinks and weakens signs of precipitation at both North and South fringes.

This should mean that though melt is reducing, SMB mass loss might still be above average for a few days more.

High pressure has been, is, and will be stuck over Greenland - but certainly looks like continuing to shrink.

The melting season now quickens its fade into history as the Greenland summer has ended, the oh so short Autumn has started and winter arrives with thump - very soon - unless something weird happens.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on August 16, 2019, 08:29:07 PM
I think 10 - 20 GT remaining seems about right.  The average is a bit less than that, but we are trending with greater loss, and the season might extend out a day or a few days.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 17, 2019, 05:26:19 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 16 August 2019

On this day
... the end-of-season downward gentle slope continues to accelerate

Melt  Same as yesterday's, so returns to average for the day..

Precipitation  not that low, and as a result ......

SMB (Surface Mass Balance) loss less than yesterday . Less than 3GT mass loss on this day, less than 1 gt more than average.
______________________________________________________
5 day outlook

Melt / Temperatures. Southern & Eastern Greenland cold. A part of the North & West still a bit above average.

Precipitation 5 day outlook.
Still looking lowish or very dry. But as the Greenland High shrinks and weakens signs of precipitation at both North and South fringes.

This should mean that though melt is reducing, SMB mass loss might still be above average for a few days more.

High pressure has been, is, and will be stuck over Greenland - but certainly looks like continuing to shrink.

The melting season now quickens its fade into history as the Greenland summer has ended, the oh so short Autumn has started and winter arrives with thump - very soon - unless something weird happens.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 18, 2019, 09:30:27 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 16 August 2019

On this day
... the end-of-season downward gentle slope continues to accelerate

Melt  Slightly lower, at average for the day..

Precipitation  not that low, and as a result ......

SMB (Surface Mass Balance) loss less than yesterday . Just over 2GT mass loss on this day, just less than average.
______________________________________________________
5 day outlook

Melt / Temperatures. Southern & Eastern Greenland cold. A part of the North & West still a bit above average.

Precipitation 5 day outlook.
Still looking lowish or very dry. But as the Greenland High shrinks and weakens signs of precipitation at both North and South fringes.

This should mean that though melt is reducing, SMB mass loss might still be above average for a few days more.

High pressure has been, is, and will be stuck over Greenland - but certainly looks like continuing to shrink.

The melting season now quickens its fade into history as the Greenland summer has ended, the oh so short Autumn has started and winter arrives with thump - very soon - unless something weird happens.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 19, 2019, 02:58:22 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 18 August 2019

On this day
... the end-of-season downward gentle slope continues to accelerate

Melt  Slightly lower, at average for the day..

Precipitation  precipitation in the far north and the far south, and as a result ......

SMB (Surface Mass Balance) loss less than yesterday . Just over 1GT mass loss on this day, at
______________________________________________________
5 day outlook

Melt / Temperatures. Almost all Greenland cold - below zero. Some small parts of the fringe with some warmth left.

Precipitation 5 day outlook.
Still looking lowish or very dry. But as the Greenland High shrinks and weakens signs of precipitation at both North and South fringes.

This should mean that though melt is reducing, SMB mass loss might still happen for a few days more.

High pressure has been, is, and will be stuck over Greenland - but certainly looks like continuing to shrink.

The melting season now quickens its fade into history as the Greenland summer has ended, the oh so short Autumn has started and winter arrives with thump - very soon - unless something weird happens.

Season over - but not quite dead?
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 20, 2019, 11:24:16 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 19 August 2019

On this day
... the end-of-season downward gentle slope continues

Melt  Slightly lower, at average for the day..

Precipitation  precipitation in the far north and the far south but a bit lower, and as a result ......

SMB (Surface Mass Balance) loss a bit more than yesterday . Nearly 2GT mass loss on this day, more than 1 G|T greater than average.
______________________________________________________
5 day outlook

Melt / Temperatures. Almost all Greenland cold - below zero. Some small parts of the fringe with some warmth left.

Precipitation 5 day outlook.
Still looking lowish or very dry for 3 days, then more precipitation in the SE. .

This should mean that though melt is reducing, SMB mass loss might still happen for a few days more.

High pressure has been, is, and will be stuck over Greenland - but certainly looks like continuing to shrink.

The melting season now quickens its fade into history as the Greenland summer has ended, the oh so short Autumn is well underway and winter arrives with thump - very soon - unless something weird happens.

Season over - but not quite dead?
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Klondike Kat on August 20, 2019, 02:00:44 PM
Gerontocrat,
Wonderful, as usual.  As we approach the end of the season, do you have an idea as to where the 2019 melt falls in relation to recent years, not just the record low?  Thanks.
Title: Re: Greenland 2019 Melt Season
Post by: johnm33 on August 20, 2019, 02:55:23 PM
Another look at the outflow from Zach/79N and Humbolt curious that despite clear evidence of flows from Jakobshvn no sign of freshwater. The second gif shows the uplift in temp around 5/6 Aug. 9c associated with the outflow at Zach/79N. 1, 30days from 27:07. 2, 10 days from 01:08

(https://media.giphy.com/media/UqvI2wbEy8OvZyqXA0/giphy.gif) (https://media.giphy.com/media/dsVvWuHjzI6KVPrbZU/giphy.gif)
Title: Re: Greenland 2019 Melt Season
Post by: blumenkraft on August 20, 2019, 05:14:36 PM
Another look at the outflow from Zach/79N and Humbolt curious that despite clear evidence of flows from Jakobshvn no sign of freshwater. The second gif shows the uplift in temp around 5/6 Aug. 9c associated with the outflow at Zach/79N. 1, 30days from 27:07. 2, 10 days from 01:08

(https://media.giphy.com/media/UqvI2wbEy8OvZyqXA0/giphy.gif) (https://media.giphy.com/media/dsVvWuHjzI6KVPrbZU/giphy.gif)

Well, warm Atlantic waters even made it up to Kane Basin. No wonder all this freshwater is getting salty...
Title: Re: Greenland 2019 Melt Season
Post by: johnm33 on August 20, 2019, 07:30:45 PM
"Well, warm Atlantic waters even made it up to Kane Basin" Or did it arrive from the north?
Title: Re: Greenland 2019 Melt Season
Post by: blumenkraft on August 20, 2019, 07:45:09 PM
Possible, but how i see it coming from the south is more likely. There is no southward surface current in NS for weeks. Mercator model sees it coming from the south too ( http://bulletin.mercator-ocean.fr/en/PSY4/animation ).
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 20, 2019, 10:03:30 PM
Gerontocrat,
Wonderful, as usual.  As we approach the end of the season, do you have an idea as to where the 2019 melt falls in relation to recent years, not just the record low?  Thanks.
Still assembling data

Attached are graphs & Tables:-

Components of SMB 1960 to 2018 - but anomalies,
Components of SMB 1980 to 2014  - actual amounts

And from a recent paper https://www.pnas.org/content/116/19/9239
Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018, which has an Excel data file attached. From that I've bashed up a graph of SMB, discharge (i.e. calving and glacier melt by seawater), and net Mass Gain / Loss.

In this paper it looks like they've defined the year as July to June. DMI use Sept to August - which is more logical.

NSIDCs Greenland Today will produce a report later this year. But I would say SMB gain this year will likely be in the bottom 5.

Still hoping for GRACE-FO Greenland Ice Sheet overall mass loss data late this month or next month to get the complete picture.


Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 21, 2019, 12:49:23 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 19 August 2019

On average, from this day average daily melt is reducing to the point that average daily precipitation exceeds melt. I.e. Surface Mass starts to increase

However, on this day[/b]...

Melt  was slightly lower, a little below average for the day..

Precipitation  precipitation in the far north and the far south but very low, and as a result..

SMB (Surface Mass Balance) loss the same as yesterday . Nearly 2GT mass loss on this day, while average loss for the day is down to zero.
______________________________________________________
5 day outlook

Melt / Temperatures. Almost all Greenland cold - below zero. Some small parts of the fringe with some warmth left, increasing a bit after 3 days.

Precipitation 5 day outlook.
Still looking lowish or very dry for 3 days, then more precipitation in the SE. .

This should mean that though melt is reducing, SMB mass loss might still happen for a few days more.

High pressure has been, is, and will be stuck over Greenland - but stabilised on a smaller scale
______________________________________________________
Speculation: GFS 5-10 Day Outlook GFS suggests that both the East and West Coast could have some much warmer days. But on the other hand precipitation on the West Coast could also be much higher. The result on SMB is the question.
___________________________________________________________________

In theory, the melting season finishes as the so short Autumn is well underway and winter arrives with a thump. But maybe one more surprise in store.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: ArcticMelt2 on August 21, 2019, 02:19:51 PM
The first data from new satellites

https://www.jpl.nasa.gov/news/news.php?feature=7481

Quote
The mission also measures mass changes in the thick ice sheets of Greenland and Antarctica. The May 2019 GRACE-FO map of Greenland shows that most of the island continued its long-term trend of ice mass loss. GRACE-FO data from June 2018 through early 2019 (see black-and-white graph) indicate a recent slowdown in Greenland ice loss that has also been observed in data from NASA's Oceans Melting Greenland airborne campaign. This slowdown has been attributed to cooler ocean waters around Greenland for the last few years.

The GRACE-FO science team is now looking at June 2019 data to assess how the unusually warm weather and rapid ice loss this summer will affect that trend. Greenland's significant ice melt in June and July this year was similar to the strong melting that occurred in the summer of 2012 and led to significant ice loss.

(https://www.jpl.nasa.gov/images/gracefo/20190820/GRACE-FO-greenland-16.jpg)
Title: Re: Greenland 2019 Melt Season
Post by: ArcticMelt2 on August 21, 2019, 02:24:26 PM
The graph confirms the data that the last winter is not very snowy (record little snow over the entire observation period).
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 22, 2019, 04:05:30 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 21 August 2019

On average, from this day average daily melt is reducing to the point that average daily precipitation exceeds melt. I.e. Surface Mass starts to increase

However, on this day[/b]...

Melt was slightly lower, a little below average for the day..

Precipitation  precipitation was low, and as a result..

SMB (Surface Mass Balance) loss a bit lower yesterday . About 1.5GT mass loss on this day, while average loss for the day is down to zero.
______________________________________________________
5 day outlook

Melt / Temperatures. Almost all Greenland cold - below zero. Some small parts of the fringe, especially the North with some warmth left, increasing a bit after 3 days.

Precipitation 5 day outlook.
Still looking lowish;

This should mean that though melt is reducing, SMB mass loss might still happen for a few days more.

High pressure has been, is, and will be stuck over Greenland - but stabilised on a smaller scale
______________________________________________________
Speculation: GFS Aug 31 & Sep 1 GFS suggests that the West Coast could have a melt event. But on the other hand GFS predicts a significant storm roaring into and up Baffin Bay on the same 2 days - with high precipitation on the West Coast including rain penetrating well inland to higher altitudes.. The result on SMB is the question - if the event happens. (GFS has to be right sometimes, doesn't it?
___________________________________________________________________

In theory, the melting season finishes as the so short Autumn is well underway and winter arrives with a thump. But maybe one more surprise in store.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 23, 2019, 08:29:10 AM
http://polarportal.dk/en/greenland/surface-conditions/ as at 22 August 2019

On average, from this day average daily melt is reducing to the point that average daily precipitation exceeds melt. I.e. Surface Mass starts to increase

However, on this day[/b]...

Melt was slightly lower, a little below average for the day..

Precipitation  precipitation was low, and as a result..

SMB (Surface Mass Balance) loss a bit lower than yesterday . About 1GT mass loss on this day, while average loss for the day is down to zero.
______________________________________________________
5 day outlook

Melt / Temperatures. Almost all Greenland cold - below zero. Some small parts of the fringe, especially the North with some warmth left.

Precipitation 5 day outlook.
Still looking lowish;

This should mean that though melt is reducing, SMB mass loss might still happen for a few days more.

High pressure has been, is, and will be stuck over Greenland - but stabilised on a smaller scale
______________________________________________________
Speculation: GFS Aug 31 & Sep 1 As usual, the GFS suggestion yesterday that the West Coast could have a melt event starting to look somewhat less impressive. And the GFS forecast of a significant storm roaring into and up Baffin Bay on the same 2 days  now becomes just an ordinary low clipping the every south of Greenland.  [iGFS has to be right sometimes, doesn't it? But not this time?[/i]
___________________________________________________________________

In theory, the melting season finishes as the so short Autumn is well underway and winter arrives with a thump.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on August 23, 2019, 02:17:53 PM
Thank you for putting all of the information here.  Is there a thread for GRACE and GRACE-FO?
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 24, 2019, 02:00:05 PM
Thank you for putting all of the information here.  Is there a thread for GRACE and GRACE-FO?
I put some stuff on "satellite news" in "science". The GRACE-FO Level-3 product of ASCII files of Ice-Sheet Mass Changes are not yet there. I was promised something this month but.....

I was thinking of opening a thread for  next year, maybe  "2019-20 Snowfall & Melt (SMB) & Overall Mass Loss" (mainly but not only using GRACE-FO Data) as that is the complete picture - snow, melt, calving/melt from sea-water.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 24, 2019, 02:07:07 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 23 August 2019

On average, from this day average daily melt is reducing to the point that average daily precipitation exceeds melt. I.e. Surface Mass starts to increase

And, on this day[/b]...

Melt was  lower, a below average for the day..

Precipitation  precipitation was up, and as a result..

SMB (Surface Mass Balance) loss was zero, while average loss for the day is down to zero.
______________________________________________________
5 day outlook

Melt / Temperatures. Almost all Greenland cold - below zero. Some small parts of the fringe, especially the North with some warmth left.

Precipitation 5 day outlook.
Still looking lowish, but with low melt probably enough to prevent any further mass loss.

This may mean the end of SMB reductions.

High pressure has been, is, and will be stuck over Greenland - but stabilised on a smaller scale
______________________________________________________
Speculation: GFS Aug 31 & Sep 1 As usual, the GFS suggestion yesterday that the West Coast could have a melt event starting looks much less impressive. But the GFS forecast of a significant storm roaring into and up Baffin Bay on the same 2 days has returned, including significant rainfall on low altitudes..  [iGFS has to be right about something sometime , doesn't it? But not this time?[/i]
___________________________________________________________________

It may well be that the melting season is over as the so short Autumn is well underway and winter will arrive with a thump fairly soon.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: Tom_Mazanec on August 25, 2019, 11:32:16 AM
How do you "do" it on these kind of threads? Does the threadstarter, or Neven, just lock it it a few days?
Title: Re: Greenland 2019 Melt Season
Post by: oren on August 25, 2019, 12:53:28 PM
The date-specific threads remain open for posterity, in case someone wants to add something later. For example if an article is published discussing the thread's subject and timeframe, or someone makes some relevant homemade charts and statistics.
Title: Re: Greenland 2019 Melt Season
Post by: Tom_Mazanec on August 25, 2019, 01:40:30 PM
I tried posting something on a 2017 Hurricane and the thread was locked? So I posted on some other peripherally related thread.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 25, 2019, 05:38:50 PM
http://polarportal.dk/en/greenland/surface-conditions/ as at 24 August 2019

Last standard daily posting - unless there is a event.
After Aug 31 time to have a closer look at the overall year 2018-2019,
with another look when / if we get GRACE-FO ASCII data to end August.

____________________________________________________________-
On average, from this day average daily melt is reducing to the point that average daily precipitation exceeds melt. I.e. Surface Mass starts to increase

And, on this day[/b]...

Melt was  lower, below average for the day..

Precipitation  precipitation was moderate, and as a result..

SMB (Surface Mass Balance) loss was zero or even a small SMB gain, while average loss for the day is also above zero.
______________________________________________________
5 day outlook

Melt / Temperatures. Almost all Greenland cold - below zero. Some small parts of the fringe, especially the North with some warmth left.

Precipitation 5 day outlook.
Still looking lowish, but with low melt probably enough to prevent any further mass loss.

This may mean the end of SMB reductions.

High pressure has been, is, and will be stuck over Greenland - but stabilised on a smaller scale
______________________________________________________
Speculation: GFS Aug 31 & Sep 1 Melt Event ? - forget it.
___________________________________________________________________

It may well be that the melting season is over as the so short Autumn is well underway and winter will arrive with a thump fairly soon.
_______________________________________________
Quote from DMI (because every so often people get confused...
Quote
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.
__________________________________________________________________
Quote
ps from me: Calving and melt from by relatively warm sea water on marine-terminating glaciers exceeds the annual overall SMB gain. It is the GRACE-FO satellite that is giving the data to give the overall net Greenland mass loss. The data up to the end of August 2019 might be produced sometime in late September. (Fingers crossed)
___________________________________________________________
Title: Re: Greenland 2019 Melt Season
Post by: Tom_Mazanec on August 25, 2019, 07:21:11 PM
Just seems kinda weird the last bit of warm weather in Greenland is in the North.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 25, 2019, 08:31:00 PM
I tried posting something on a 2017 Hurricane and the thread was locked? So I posted on some other peripherally related thread.
Neven can lock any thread at any time.
You can lock any thread you have created.

So either Neven locked it or the person who created it locked it.

These things happen from time to time.

Title: Re: Greenland 2019 Melt Season
Post by: Klondike Kat on August 26, 2019, 03:24:17 PM
Gerontocrat,
Excellent posts, as usual.  As this season draws to a close, I look forward to your next thread.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 27, 2019, 01:56:29 PM
http://polarportal.dk/en/greenland/surface-conditions/ 25 & 26 Aug 2019

No significant event, but average melt and lowish precipitation means a small SMB loss instead of a small gain

The season is dying but not quite dead.
Title: Re: Greenland 2019 Melt Season
Post by: Susan Anderson on August 27, 2019, 05:17:06 PM
Gerontocrat,
Excellent posts, as usual.  As this season draws to a close, I look forward to your next thread.
What KKat said.
Title: Re: Greenland 2019 Melt Season
Post by: RealityCheck on August 27, 2019, 09:51:20 PM
Gerontocrat
May I also offer a hat-tip for another season of consistent data posting on ASIF. Many thanks.
RC
Title: Re: Greenland 2019 Melt Season
Post by: Tom_Mazanec on August 29, 2019, 10:23:44 PM
Climate change melts 12.5bn tons of ice in Greenland 50 years earlier than predicted
https://www.telegraph.co.uk/news/2019/08/28/climate-change-melts-billions-tons-ice-greenland-fifty-years/
Quote
Billions of tonnes of ice in Greenland is melting 50 years ahead of climate change schedules, preventing inhabitants from moving around the country by sledge and leading to the surreal spectacle of children playing in the Arctic sea due to rising temperatures.

A heatwave gripping the Arctic region is causing unprecedented levels of melting ice, and has also seen global sea levels rise, in a clear sign that climate change is taking its severe toll much more quickly than predicted.
Title: Re: Greenland 2019 Melt Season
Post by: grixm on August 30, 2019, 12:49:12 PM
Season is not over yet. Currently and over the next few days, the western and northern coast is getting roasted. Temperature anomalies +10C in some places.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 30, 2019, 02:23:29 PM
Season is not over yet. Currently and over the next few days, the western and northern coast is getting roasted. Temperature anomalies +10C in some places.
Very true - melt on average continues, gradually reducing, until the end of September, and there will be warm days (& cold days).

However, on the other hand precipitation increases - as Autumn / Winter storms increase (as was supposed to happen in the Arctic Ocean - prolonging extent and area loss).

So although there is melt, the SMB - Surface Mass Balance increases. And this is the key reason that DMI chose September to August as the Greenland year for analysing the data.

Mind you, as the years go by the models suggest that precipitation will increase, and so will rainfall instead of snowfall especially at lower latitudes. And when there are SMB losses after August 31 it will be a real event. That's AGW - messing up the scientists' nice neat definitions of the seasons.

So I have no intention of closing this thread, but I am going to open a Greenland 2019-20 SMB (Snowfall and Melt)  thread to initially occasionally post DMI's data on progress of the snowfall and remaining melt.

Meanwhile.... http://polarportal.dk/en/greenland/surface-conditions/ 27-29 Aug 2019

Average melt but increasing precipitation has led to SMB gains to above 1 GT.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on August 31, 2019, 01:58:47 PM
http://polarportal.dk/en/greenland/surface-conditions/ 30 Aug 2019

Average melt up a little bit to just above average, and slightly lower precipitation has led to an SMB loss of 1 GT compared to an average gain of 1 GT on this day.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on September 01, 2019, 02:15:34 PM
http://polarportal.dk/en/greenland/surface-conditions/ 31 Aug 2019

Average melt up a little bit to just above average, and but higher precipitation has led to an SMB gain at around average for the day..
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on September 01, 2019, 03:02:14 PM
The DMI Surface Mass Balance (SMB) year is over, but the melting season is not.

Nevertheless, here is a gif of the melting season to date since late June. Sorry, no images from May when it started. (next year?)

Click to start - should slow down a bit at the peak melting.
Title: Re: Greenland 2019 Melt Season
Post by: NotaDenier on September 01, 2019, 03:38:31 PM
The DMI Surface Mass Balance (SMB) year is over, but the melting season is not.

Nevertheless, here is a gif of the melting season to date since late June. Sorry, no images from May when it started. (next year?)

Click to start - should slow down a bit at the peak melting.

Love the gif. I was thinking an animation would be useful back in july, but didn’t want to bug you and you already do too much.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on September 03, 2019, 05:18:56 PM
First look at the DMI Greenland Year Sept 2018 to Aug 2019

Precipitation (Snowfall).
On average before melting starts in earnest, SMB increases by an average of around 580 GT from August to early June, i.e. dominated by snowfall.

The 2018-19 snowfall was at or below average for most of the time, with SMB increase about 60 GT lower than average, giving an SMB gain during this snowfall dominated part of the year of about 520 GT

(In contrast, 2012 saw an average SMB gain in this period)

Melt  started early, with a brief spike in April and then persistent melt above precipitation by the 3rd week in May.

As a result Surface Mass Balance (SMB) started consistent daily losses by the third week in May, about 2 weeks earlier than average, effectively extending the season for SMB losses by about 15%.

(In 2012, SMB loss commenced only a very few days earlier than average)

SMB losses during the melting period in 2018-19 were around 350GT,  about 130 GT more than the average of 220GT.

(In 2012, SMB losses during the melting period were a massive 540 GT)

So net SMB gain for the 2018-19 year was around 170 GT, about 300 GT less than the average yearly gain of 360 GT.

(In 2012, the net SMB gain was about 40 GT)

SUMMARY 2019 vs 2012
In 2012, because snowfall was average, the record low net gain was caused entirely by melt.
In 2019, the low net gain in SMB was mostly from melting, but partly from low snowfall.

2019 melt of 350 GT,
2012 Melt of 540 GT.

In other words, 2019 was an above average melt year, and an early melt year.
But NOT in the same league for melting as 2012.
Title: Re: Greenland 2019 Melt Season
Post by: Stephan on September 03, 2019, 10:44:56 PM
Gerontocrat - thank you for this analysis.
I have picked up from somewhere that 360 Gt ice melt results in 1 mm sea level rise [if this isn't correct, please tell me, in this case I will revise my notes]. So Greenland has almost made this millimeter in the 2019 melting season.
Title: Re: Greenland 2019 Melt Season
Post by: kassy on September 04, 2019, 02:32:21 PM
From a BBC article on Greenland melt:

Recent years have seen hundreds of billions of tonnes of ice lost - and a rough guide to the effect on sea level is that 362 billion tonnes of melt raises the average ocean level by a millimetre.

https://www.bbc.com/news/science-environment-49483580

Title: Re: Greenland 2019 Melt Season
Post by: Observer2019 on September 04, 2019, 06:01:37 PM
Gerontocrat - thank you for this analysis.
I have picked up from somewhere that 360 Gt ice melt results in 1 mm sea level rise [if this isn't correct, please tell me, in this case I will revise my notes]. So Greenland has almost made this millimeter in the 2019 melting season.

The SMB of Greenland (snow vs melt ratio) is never negative including the low of 2012 (+50GT). Any mass loss is due to calving only (which is mostly due to pressure of falling snow). Is there any data on mass of calving?
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on September 05, 2019, 07:38:12 PM
It looks like Dorian will pass just south of Greenland as a Tropical Storm.  Any thoughts / predictions on impact to the SMB?

I am not sure how much will fall as rain versus snow at higher elevations...
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on September 05, 2019, 08:23:07 PM
Gerontocrat - thank you for this analysis.
I have picked up from somewhere that 360 Gt ice melt results in 1 mm sea level rise [if this isn't correct, please tell me, in this case I will revise my notes]. So Greenland has almost made this millimeter in the 2019 melting season.

The SMB of Greenland (snow vs melt ratio) is never negative including the low of 2012 (+50GT). Any mass loss is due to calving only (which is mostly due to pressure of falling snow). Is there any data on mass of calving?
Mass loss is caused by calving and contact of marine-terminating glaciers with relatively warm ocean water. This latter melt is, apparently, much more significant than previously thought.

Calving is due to flow of the glaciers to the ocean edge, and is from gravity. Obviously snowfall is increasing downward weight, but the annual increase from a few metres of snow is far less important than the 1 to 3 kms thickness of the ice sheet. It seems that the average rate of  flow of glaciers to the ocean is double in summer, due to meltwater seeping through the glaciers (moulins etc) to the ice rock boundary - reducing friction.

We have data from 2 main sources on calving/melt by the ocean and overall mass change (SMB minus calving).

1- studies and field measurements. The latest one I've read (and copied their speadsheet) is
https://www.pnas.org/content/116/19/9239 Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018 - It is damn good

See attached graphs from the paper and one I made from their spreadsheet.

2- GRACE and GRACE-FO Mass Change data. I attach the latest graph I made from their data. I am still waiting for GRACE-FO to produce the data on a regular basis.

Net mass loss of the Greenland Ice Sheet is in excess of 200 GT per annum.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on September 05, 2019, 09:59:29 PM
A long BBC article about Greenland's ice sheet.

https://www.bbc.co.uk/news/science-environment-49483580

Not hard science but a good intro.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on September 06, 2019, 09:15:17 PM
Germany is back from holiday and it looks like they are getting their GRACE-FO act together.

Corrected GRACE Ice Mass Data (still only to May 219) was posted, and I was able to add the map. Hopefully we will see later data apearing more regularly from now.

More details tomorrow on Greenland and about Antarctica (with links).

It is why have changed the name for the 2019-20 year as we will have much more complete data.

EDIT - Another Graph before bedtime
Title: Re: Greenland 2019 Melt Season
Post by: FrostKing70 on September 06, 2019, 09:43:15 PM
Fascinating stuff, as usual!

Does anyone know if there is a similar graph for the basins, but done in percentage terms instead of GT?   

I stared at the graph for a while trying to understand why the orange (302) and red (305) lines were nearly flat.   Basin 302 feels correct, as the color coding is a mix of small gains and losses.   It took longer for it to sink in on basin 305, as most of the area shows significant loss.   
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on September 06, 2019, 10:10:36 PM
Fascinating stuff, as usual!

Does anyone know if there is a similar graph for the basins, but done in percentage terms instead of GT?   

I stared at the graph for a while trying to understand why the orange (302) and red (305) lines were nearly flat.   Basin 302 feels correct, as the color coding is a mix of small gains and losses.   It took longer for it to sink in on basin 305, as most of the area shows significant loss.

Does anyone know if there is a similar graph for the basins, but done in percentage terms instead of GT?   

I know, because it is I who have made these graph from the raw data that only appeared on the website today.

And there isn't because I have not made it yet.

HINT:- That is why they say - prepared by GERONTOCRAT
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on September 23, 2019, 02:41:57 PM
Been diverted from Greenland by the end of sea ice melt season.

No new data from GRACE-FO. Shame.

Also have to wait for end of year autopsies from DMI and NSIDC Greenland today.

So to keep the thread alive, here is a gif showing the 2019 melt season dying. Note the flicker of life on the last day - 22 Sept. Click to start.
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on October 01, 2019, 09:04:46 PM
No new data from GRACE-FO. Shame. Time to send a begging e-mail.

Also have to wait for end of year autopsies from DMI and NSIDC Greenland today.

Here is a probably the last gif showing the 2019 melt season dying.
[/quote]
Title: Re: Greenland 2019 Melt Season
Post by: gerontocrat on October 09, 2019, 04:03:12 PM
In full the report about 2019 - not found on the DMI website, but here..

https://skepticalscience.com/how-greenland-ice-sheet-fared-2019.html

need 2 months more GRACE-FO data and the story will be complete- early December with luck. It will test their estimates of mass loss from calving & ocean seawater contact melting
_________________________________________________________   
How the Greenland ice sheet fared in 2019
Posted on 7 October 2019 by Guest Author
This is a re-post from Carbon Brief


Dr Ruth Mottram, Dr Martin Stendel and Dr Peter Langen are climate scientists at the Danish Meteorological Institute (DMI) in Copenhagen, which is part of the Polar Portal. Dr Andreas Ahlstrøm and Dr Kenneth D. Mankoff are chief research consultant and senior scientist at the Geological Survey of Denmark and Greenland, respectively.

As the end of August sees summer shift into autumn for the northern hemisphere, it also marks the end of the melt season for the Greenland ice sheet.

The advent of a new season is the traditional time for our annual look back at the year gone by and what it tells us about the state ice sheet.

Our estimates show that the surface of the ice sheet gained 169bn tonnes of ice over 2018-19 – this is the seventh smallest gain on record.

And using new satellite data, we show that – once all ice sheet processes are factored in for the past year – the Greenland ice sheet saw a net decline of 329bn tonnes in ice.

Surface processes
While western calendars show another four months before a new year, scientists generally consider the beginning of September as the start of a new annual cycle for the Greenland ice sheet.

This yearly pattern sees the ice sheet largely gain snow from September, accumulating ice through autumn, winter and into spring. Then, as the year warms up into late spring, the ice sheet begins to lose more ice through surface melt than it gains from fresh snowfall. This melt season generally continues until the end of August.

The contrast between snow gains and ice losses at the surface over the whole year is known as the “surface mass balance” (SMB). The chart below shows the SMB for 2018-19 on individual days (top) and cumulatively across the year (bottom). The blue lines show 2018-19 data and the grey line shows the long-term average. The lower chart also shows the record low year in 2011-12 (red line) for comparison.
click to see

https://www.carbonbrief.org/wp-content/uploads/2019/09/SMB_curves_LA_EN_20190831.png

Daily (upper chart) and cumulative (lower) surface mass budget of the Greenland ice sheet, in billion tonnes per day, and billion tonnes, respectively. Blue lines show 2018-19 SMB year; the grey lines show the 1981-2010 average; and the red line in lower chart shows the record low SMB year of 2011-12. Credit: DMI Polar Portal.

This year has been an unusual one. It has been consistently drier than normal, which is reflected in the below-average gains in snow throughout the year. And the summer has been warm with some periods of very high melt.

Overall, while the 2016-17 and 2017-18 seasons saw above-average gains in ice at the surface, the SMB in 2018-19 ends as the seventh lowest on record. The total accumulated SMB was only 169bn tonnes at the end of the year. This means that nine of the Top 10 lowest SMB years have occurred in the last 13 years in our record that goes back to 1981.

Total losses
It is important to remember that SMB is always positive at the end of the year – more snow falls on the ice sheet than melts at the surface. But the ice sheet also loses ice by the breaking off, or “calving”, of icebergs and from ocean melting at its edge. Therefore, the extra snowfall is needed in order to compensate for these processes.

Observations collected by the European Space Agency’s Sentinel-2 satellite measure ice velocity of outlet glaciers around the edges of the ice sheet. By measuring how quickly the ice moves into the ocean we can work out how much ice is being lost by calving and ocean melting.

On average between 1986 and 2018, the ice sheet discharges about 462bn tonnes per year. This year our analysis suggests Greenland discharged around 498bn tonnes of ice.

Factoring in these additional processes, we can calculate the total mass budget for the ice sheet for the year. For 2018-19, we estimate the ice sheet has seen a total net ice loss of around 329bn tonnes.

Data from the GRACE satellites indicate that Greenland lost an average of approximately 260bn tonnes of ice per year between 2002 and 2016, with a peak of 458bn in 2012. Clearly, the loss of 329bn tonnes we estimate this year is significantly above the 260bn tonne long-term average, but we have not broken the highest record for ice loss in a year.

Long, dry summer
The high losses this year were from a combination of factors. The SMB year started in September 2018 with a long dry period – a much drier than usual winter over most of Greenland (only the south-east had more snow than usual). This left the ice sheet with only a thin protective cover that melted quickly in the lower areas when the melt season got going on the 30 April.

In fact, 2019 saw the second earliest start to the melt season on record – after 2016 – when an unusual spike in melting occurred in early April. The summer that followed was very long, dry and warm, with substantial melting all over the ice sheet and especially in the west and north.

The map below shows how the SMB at the end of the 2018-19 season compared with the long-term average. The shading indicates higher (blue) and lower (red) gains in ice than usual over the year. You can see that the majority of the ice sheet gained less ice than average.

click to see

https://www.carbonbrief.org/wp-content/uploads/2019/09/SMB_map_LA_acc_EN_20190831.png