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BenB

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Re: Greenland 2019 Melt Season
« Reply #50 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.

gerontocrat

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Re: Greenland 2019 Melt Season
« Reply #51 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.
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b_lumenkraft

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Re: Greenland 2019 Melt Season
« Reply #52 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)

Niall Dollard

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Re: Greenland 2019 Melt Season
« Reply #53 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).  :)

b_lumenkraft

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Re: Greenland 2019 Melt Season
« Reply #54 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.

b_lumenkraft

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Re: Greenland 2019 Melt Season
« Reply #55 on: May 02, 2019, 05:45:04 AM »
I imagine you mean the other way around. (29th less cover).  :)

Indeed. Sorry for the confusion.

Darvince

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Re: Greenland 2019 Melt Season
« Reply #56 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.

gerontocrat

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Re: Greenland 2019 Melt Season
« Reply #57 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.

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jai mitchell

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Re: Greenland 2019 Melt Season
« Reply #58 on: May 02, 2019, 08:57:34 PM »
Haiku of Past Futures
My "burning embers"
are not tri-color bar graphs
+3C today

johnm33

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Re: Greenland 2019 Melt Season
« Reply #59 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.

magnamentis

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Re: Greenland 2019 Melt Season
« Reply #60 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
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gerontocrat

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Re: Greenland 2019 Melt Season
« Reply #61 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.
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gerontocrat

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Re: Greenland 2019 Melt Season
« Reply #62 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?
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be cause

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Re: Greenland 2019 Melt Season
« Reply #63 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.
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mabarnes

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Re: Greenland 2019 Melt Season
« Reply #64 on: May 03, 2019, 05:42:16 PM »
Hmmm....

ms

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Re: Greenland 2019 Melt Season
« Reply #65 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)

be cause

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Re: Greenland 2019 Melt Season
« Reply #66 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.
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pauldry600

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Re: Greenland 2019 Melt Season
« Reply #67 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.

Shared Humanity

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Re: Greenland 2019 Melt Season
« Reply #68 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.

magnamentis

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Re: Greenland 2019 Melt Season
« Reply #69 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 ;)
« Last Edit: May 05, 2019, 10:27:48 PM by magnamentis »
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oren

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Re: Greenland 2019 Melt Season
« Reply #70 on: May 05, 2019, 09:04:35 PM »
Don't forget the gravitational effect. No SLR around Greenland - it will be the opposite.

magnamentis

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Re: Greenland 2019 Melt Season
« Reply #71 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 ;)

« Last Edit: May 05, 2019, 10:45:24 PM by magnamentis »
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oren

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Re: Greenland 2019 Melt Season
« Reply #72 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.

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RoxTheGeologist

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Re: Greenland 2019 Melt Season
« Reply #74 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.

ghoti

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Re: Greenland 2019 Melt Season
« Reply #75 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)

magnamentis

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Re: Greenland 2019 Melt Season
« Reply #76 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.

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sidd

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Re: Greenland 2019 Melt Season
« Reply #77 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
« Last Edit: May 06, 2019, 05:32:02 AM by sidd »

kiwichick16

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Re: Greenland 2019 Melt Season
« Reply #78 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

FrostKing70

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Re: Greenland 2019 Melt Season
« Reply #79 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/
 

oren

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Re: Greenland 2019 Melt Season
« Reply #80 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.

magnamentis

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Re: Greenland 2019 Melt Season
« Reply #81 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
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RoxTheGeologist

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Re: Greenland 2019 Melt Season
« Reply #82 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.

magnamentis

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Re: Greenland 2019 Melt Season
« Reply #83 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
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Tor Bejnar

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Re: Greenland 2019 Melt Season
« Reply #84 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 - 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).
Arctic ice is healthy for children and other living things.

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Re: Greenland 2019 Melt Season
« Reply #85 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.
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magnamentis

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Re: Greenland 2019 Melt Season
« Reply #86 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
« Last Edit: May 06, 2019, 10:31:54 PM by magnamentis »
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oren

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Re: Greenland 2019 Melt Season
« Reply #87 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.

sidd

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Re: Greenland 2019 Melt Season
« Reply #88 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

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Re: Greenland 2019 Melt Season
« Reply #89 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.
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Re: Greenland 2019 Melt Season
« Reply #90 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, 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.
« Last Edit: May 07, 2019, 12:28:08 AM by Tor Bejnar »
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Tor Bejnar

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Re: Greenland 2019 Melt Season
« Reply #91 on: May 07, 2019, 12:48:20 AM »
Rising Oceans Guaranteed: Arctic Land Ice Loss and Sea Level Rise
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!
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sidd

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Re: Greenland 2019 Melt Season
« Reply #92 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



« Last Edit: May 07, 2019, 01:49:06 AM by sidd »

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Re: Greenland 2019 Melt Season
« Reply #93 on: May 07, 2019, 05:50:30 AM »
Mitrovica   It is just dull plain Newtonian physics. 

youtube-dl   ""   

and

youtube-dl ""


gerontocrat

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Re: Greenland 2019 Melt Season
« Reply #94 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.
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johnm33

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Re: Greenland 2019 Melt Season
« Reply #95 on: May 07, 2019, 04:56:24 PM »
The meltwater showing up in Baffin

or zoom in on the hycom animation, https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsss_nowcast_anim30d.gif

gerontocrat

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Re: Greenland 2019 Melt Season
« Reply #96 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.
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Tor Bejnar

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Re: Greenland 2019 Melt Season
« Reply #97 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!]
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gerontocrat

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Re: Greenland 2019 Melt Season
« Reply #98 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.
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gerontocrat

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Re: Greenland 2019 Melt Season
« Reply #99 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.
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