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Neven

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Greenland 2018 melt season
« on: January 05, 2018, 02:55:39 PM »
It's not the melt season yet, but it is 2018, so have at it.
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #1 on: January 05, 2018, 03:24:06 PM »
Data as at 4 January 2018 from-

https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

Greenland surface mass gain still continues very much on the low side, and cci-reanalyzer again predicts low precipitation over the next few days.

The high precipitation of September and October is pretty well matched by very low precipitation in November and December that is continuing in January.

So I have even another week of data for "my theory that belongs to me", i.e. that the decline in precipitation that started in November coincides with the onset and continuance of La Nina conditions and this is not a coincidence.

AbruptSLR on the ENSO thread tells us that data continues to suggest that the current weak La Nina may be on its way out. Will this test my little theory in the months to come ?
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #2 on: January 06, 2018, 10:43:26 PM »
Greenland stays very dry.
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #3 on: January 08, 2018, 03:29:59 PM »
So some days even in darkest January, there is a bit of warming in Greenland.
(Less than 1% so does not show on the graph on https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #4 on: January 13, 2018, 01:34:46 PM »
There has been precipitation mainly on the SE coast due to that big weather system twixt Greenland and Scandinavia pushing north. Note the tiny bit of melting on the extreme SE coast.

But cci-reanalyzer suggests this precipitation will move further north and fade away over the next few days.
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #5 on: January 14, 2018, 02:58:24 PM »
A second day with a little bit of melt on the SE Coast. All due to that whopping cyclone sending warmth into the far North Atlantic. (see Arctic Sea Ice - 2017-18 Freezing Season).
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #6 on: January 20, 2018, 11:28:46 AM »
Another week gone and not a lot happening.

A bit of precipitation in the week now fading away and the rest of January looks to be very quiet - little precipitation.

The absence of major precipitation events since October in this 2017-18 season is in stark contrast to 2016-2017. I wonder when will be the first day of measurable melting. Every day the sun moves a bit further north and a bit higher in the sky.
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Daniel B.

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Re: Greenland 2018 melt season
« Reply #7 on: January 20, 2018, 02:47:17 PM »
Yes, this winter has moved almost exactly on top of the long-term average.  It just be interesting to see how the rest of the winter plays out.  Regarding the onset of melt, I think we have several months to go.  The waters are still getting colder, and the ice growing.

gerontocrat

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Re: Greenland 2018 melt season
« Reply #8 on: January 21, 2018, 01:27:21 PM »
Regarding the onset of melt, I think we have several months to go.  The waters are still getting colder, and the ice growing.
I think you may have misunderstood my post - I meant melting on the Greenland mainland... This happens occasionally even in January - it did yesterday, but not enough to register on the graph - unless you have a microscope handy.

See images below from https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/
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Daniel B.

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Re: Greenland 2018 melt season
« Reply #9 on: January 21, 2018, 04:07:36 PM »
No, I understood.  I was simply stating that significant melt will not occur until warmer waters offshore create consistently warmer air temperatures.  Some sun-enhanced melt will always occur - even in January.  However, most of this tends to refreeze.

gerontocrat

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Re: Greenland 2018 melt season
« Reply #10 on: January 22, 2018, 10:11:50 AM »
21 Jan saw a second day of melt on the far SW coast, looking stronger but still not sufficient for a mention on the graph. If it persists is significant?
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lifeblack

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Re: Greenland 2018 melt season
« Reply #11 on: January 22, 2018, 11:50:16 PM »
The chart shows surface mass balance... Does it also include sublimation?  (ie, is it necessary to invoke melting to explain the red area?)

gerontocrat

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Re: Greenland 2018 melt season
« Reply #12 on: January 23, 2018, 12:03:40 AM »
The chart shows surface mass balance... Does it also include sublimation?  (ie, is it necessary to invoke melting to explain the red area?)
Yep, melting includes sublimation
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lifeblack

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Re: Greenland 2018 melt season
« Reply #13 on: January 23, 2018, 12:48:39 AM »
The chart shows surface mass balance... Does it also include sublimation?  (ie, is it necessary to invoke melting to explain the red area?)
Yep, melting includes sublimation

Sublimation is distinctly different from melting... it shouldn't appear on the %surface melt graph, even though the SMB is negative.

gerontocrat

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Re: Greenland 2018 melt season
« Reply #14 on: January 23, 2018, 10:13:07 AM »
The chart shows surface mass balance... Does it also include sublimation?  (ie, is it necessary to invoke melting to explain the red area?)
Yep, melting includes sublimation

Sublimation is distinctly different from melting... it shouldn't appear on the %surface melt graph, even though the SMB is negative.
The objective of DMI is to show the "Current Surface Mass Budget of the Greenland Ice Sheet" by displaying additions in mass (precipitation) and reductions in mass (melting and sublimation).
So for the purpose of the website surely it is correct to include sublimation on the minus side (even though for other purposes sublimation would be separated from melting).

Precipitation remains below average, and looks to continue at a low level for a few days - maybe the line for the year will dip below the average? Also sublimation(?) continues for a third day.
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oren

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Re: Greenland 2018 melt season
« Reply #15 on: January 23, 2018, 12:22:32 PM »
SMB includes sublimation, %surface melt does not.

gerontocrat

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Re: Greenland 2018 melt season
« Reply #16 on: January 23, 2018, 01:16:46 PM »
SMB includes sublimation, %surface melt does not.

Yep - lazy me did not read the notes to the images properly.
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #17 on: February 02, 2018, 03:02:00 PM »
Data from https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

January was average to below average precipitation, again in contrast to last year, and continuing the marked change that started in early November (La Nina influence? who knows). Indeed, the accumulated precipitation has threatened to dip below average.

Feb 1 has started the new month with a spike - perhaps associated with the development of a  possible extreme cyclone starting in Southern Greenland and then charging up into the Greenland Sea and beyond to over the North Pole from Sunday to Tuesday. (My observations suggest that often these cyclones in the Greenland and Norwegian seas do NOT result in much Greenland precipitation.)

Of note also is while Greenland precipitation (i.e. snow) is average or below average - the Northern Hemisphere Snow Water Equivalent is really, really high.
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #18 on: February 02, 2018, 08:53:38 PM »
Indeed, the accumulated precipitation has threatened to dip below average.

WHOOPS FORGOT TO ADD IMAGE
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FrostKing70

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Re: Greenland 2018 melt season
« Reply #19 on: February 05, 2018, 07:04:50 PM »
Does anyone have access to prior years "Greenland Cumulative Melt Days" on Dec 31st of each year?   I am wondering what a time lapse of all the previous year end cumulative melt graphics would look like?   Would it show a pattern of increasing melt days, or a random pattern?

https://nsidc.org/greenland-today/images/greenland_cumulative_melt.png

Niall Dollard

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Re: Greenland 2018 melt season
« Reply #20 on: February 05, 2018, 10:37:55 PM »
This paper by Tomas Mote covers the period from 1973 -2007 and has a chart of summer seasonal melt departure. It shows a pretty much steady increase from 1987 but especially so after 1996.

 http://onlinelibrary.wiley.com/doi/10.1029/2007GL031976/epdf

Pmt111500

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Re: Greenland 2018 melt season
« Reply #21 on: February 08, 2018, 04:01:38 PM »
I haven't really followed the melt season in Greenland after 2012, but maybe this year. Hope the Trumpistan Republicans haven't thrown this resource in a bin.
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #22 on: February 08, 2018, 04:46:46 PM »
I haven't really followed the melt season in Greenland after 2012, but maybe this year. Hope the Trumpistan Republicans haven't thrown this resource in a bin.

If Trumpistan kills it - there are always the Danes:-

https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/
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gerontocrat

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Re: Greenland 2018 melt season
« Reply #23 on: February 08, 2018, 05:07:48 PM »
https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

That damn cyclone is doing a mischief to "my theory that belongs to me", (i.e. that the decline in precipitation that started in November coincides with the onset and continuance of La Nina conditions and this is not a coincidence).

Precipitation has been up, and it rather looks like that after a couple of days weather systems marching up the Greenland Sea are going to dump a lot of white stuff for a good many days to come. But do not despair, Gerontocrat, it seems La Nina is going to be around for a good few months yet.
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Daniel B.

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Re: Greenland 2018 melt season
« Reply #24 on: February 08, 2018, 07:24:08 PM »
It may just be a weather anomaly.  Over the long term, your theory that belongs to you may still prevail.

gerontocrat

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Re: Greenland 2018 melt season
« Reply #25 on: February 08, 2018, 08:38:47 PM »
It may just be a weather anomaly.  Over the long term, your theory that belongs to you may still prevail.
But not this month. See recent posts on the Freezing Season thread, and
be afraid, be very afraid
. And I thought February was supposed to be a quiet month.

https://watchers.news/2018/02/08/warnings-issued-as-sudden-stratospheric-warming-threatens-europe-with-big-freeze/

Warnings issued as Sudden Stratospheric Warming threatens Europe with big freeze

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gerontocrat

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Re: Greenland 2018 melt season
« Reply #26 on: February 12, 2018, 12:55:20 PM »
https://www.dmi.dk/en/groenland/maalinger/greenland-ice-sheet-surface-mass-budget/

That damn cyclone didn't do much of a mischief to "my theory that belongs to me", (i.e. that the decline in precipitation that started in November coincides with the onset and continuance of La Nina conditions and this is not a coincidence). Precipitation went up, and then went down, so precipitation to date is bumbling along at about average.

This is in marked contrast to Northern Hemisphere Snow Water Equivalent, which is way up. (graph below). The generally accepted hypothesis seems to be that as warmer temperatures increase the capacity of air to hold water, one should see more snow in winter. In Greenland, this held true last year (5th highest surface mass gain in the satellite records ?), but is not holding true so far this year since late October 2017 (DMI defines the year as 1 Sept to 31 Aug).
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Daniel B.

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Re: Greenland 2018 melt season
« Reply #27 on: February 13, 2018, 12:21:34 AM »
The theory that one should see more snow in winter only holds for those areas that have an average temperature below zero.  In other areas, precipitation increases, but more falls as rain, cancelling out the higher snowfall potential.  In Greenland, I would expect more winter snowfall - all other things being equal.

FishOutofWater

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Re: Greenland 2018 melt season
« Reply #28 on: February 13, 2018, 03:49:02 PM »
I hate that oversimplified explanation because it implies things that are false.

The generally accepted hypothesis seems to be that as warmer temperatures increase the capacity of air to hold water, one should see more snow in winter.

Air doesn't "hold" water vapor. Water vapor is a completely miscible component of air. You can boil water vapor into air until your pot runs dry. The air doesn't care. Of course, your cool windows will quickly fog up.

The vapor pressure of water is a function of temperature. The ocean is the primary source of water vapor around Greenland and the ocean water has a huge heat capacity. Thus, ocean water temperatures buffer the air temperatures and sea surface temperatures are the controlling factor on the maximum vapor pressure of water. Obviously, wind speeds and mixing are important factors affecting the amount of precipitable water in the atmosphere.

Susan Anderson

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Re: Greenland 2018 melt season
« Reply #29 on: February 16, 2018, 05:46:17 PM »
I hate that oversimplified explanation because it implies things that are false.

The generally accepted hypothesis seems to be that as warmer temperatures increase the capacity of air to hold water, one should see more snow in winter.

Air doesn't "hold" water vapor. Water vapor is a completely miscible component of air. You can boil water vapor into air until your pot runs dry. The air doesn't care. Of course, your cool windows will quickly fog up.

The vapor pressure of water is a function of temperature. The ocean is the primary source of water vapor around Greenland and the ocean water has a huge heat capacity. Thus, ocean water temperatures buffer the air temperatures and sea surface temperatures are the controlling factor on the maximum vapor pressure of water. Obviously, wind speeds and mixing are important factors affecting the amount of precipitable water in the atmosphere.

I altered the "pink" to "brown" because it was almost illegible.

Thanks for continuing to put these concepts in plain English!

gerontocrat

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Re: Greenland 2018 melt season
« Reply #30 on: February 16, 2018, 07:07:10 PM »
I hate that oversimplified explanation because it implies things that are false.

The generally accepted hypothesis seems to be that as warmer temperatures increase the capacity of air to hold water, one should see more snow in winter.

Air doesn't "hold" water vapor. Water vapor is a completely miscible component of air. You can boil water vapor into air until your pot runs dry. The air doesn't care. Of course, your cool windows will quickly fog up.

The vapor pressure of water is a function of temperature. The ocean is the primary source of water vapor around Greenland and the ocean water has a huge heat capacity. Thus, ocean water temperatures buffer the air temperatures and sea surface temperatures are the controlling factor on the maximum vapor pressure of water. Obviously, wind speeds and mixing are important factors affecting the amount of precipitable water in the atmosphere.

I altered the "pink" to "brown" because it was almost illegible.

Thanks for continuing to put these concepts in plain English!
Thanks for continuing to put these concepts in plain English!

Huh! he said, with a downward curl of the lip.

"Water vapor is a completely miscible component of air."  Miscible ? Huh!
"The vapor pressure of water"  vapor pressure Huh!

Explain that to the Joe Public I meet in the pub. Double huh!

Just back from the pub extremely irritated by a man who should know better.

"the climate has always changed",
"ice is increasing, not decreasing"
"its all a scam by governments, scientists etc etc"
"sea level rise is a myth - the Florida keys are still there"
and so on, and so on.....

Ho hum.
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FredBear

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Re: Greenland 2018 melt season
« Reply #31 on: February 16, 2018, 07:36:42 PM »
I hate that oversimplified explanation because it implies things that are false.

The generally accepted hypothesis seems to be that as warmer temperatures increase the capacity of air to hold water, one should see more snow in winter.

Air doesn't "hold" water vapor. Water vapor is a completely miscible component of air. You can boil water vapor into air until your pot runs dry. The air doesn't care. Of course, your cool windows will quickly fog up.


   .    .   but if air containing water vapour cools it may become super-saturated with water vapour, which will condense out on suitable "seeds" to form clouds or fog surfaces = the air cannot "hold" the water vapour as vapour?  Most of the water vapour reaches the atmosphere further south where the ocean is warmer and forms clouds as it moves to higher latitudes. It is easier to evaporate more water at higher temperatures, offering more potential for condensation as rain or snow.
[Sorry, OT nit-pick]

gerontocrat

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Re: Greenland 2018 melt season
« Reply #32 on: February 16, 2018, 08:02:30 PM »
Most of the water vapour reaches the atmosphere further south where the ocean is warmer and forms clouds as it moves to higher latitudes. It is easier to evaporate more water at higher temperatures, offering more potential for condensation as rain or snow.
[Sorry, OT nit-pick]
You mean as in the image below? Not OT in my opinion - seems to me from my un-collated observations that most of the Greenland precipitation is from a long way away (amospheric rivers?), not locally generated weather systems.

cci-reanalyzer 24 Feb
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