Puzzled.

[Digit]

I'm sure we all have heard of the loss of ice on the Petermann Glacier but this picture puzzles me. Anyone else see something odd?

http://www.google.co.uk/url?sa=t&source ... PA&cad=rja

Roy.

 

[Shultzy]

No, please enlighten.

 

[Digit]

I don't wish to 'lead' anybody so if you don't mind I'll wait a while and see if it's just me.

Roy.

 

[adidat]

go on, give us a clue

adidat

 

[Digit]

Well, how is there open water at the tail of the glacier?

Roy.

 

[adidat]

oh exactly what i was thinking :---)

adidat

 

[Digit]

Oooh you fibber you! :lol:

Roy.

 

[CHJ]

Surely a considerable length of the lower reaches is floating on warmer water not on land.

 

[Digit]

Then how is there Pack ice further down the Fjord?

Roy.

 

[Tom K]

Where Roy?

 

[Digit]

Well Sea ice if you prefer.

Roy.

 

[Tom K]

Isn't the land generally warmer than the ocean?

 

[Digit]

As I understand it, based on my local conditions, that would depend on the season due to the greater level of thermal lag demonstrated by land as opposed to water.

Roy.

 

[adidat]

quick kids down to the anderson! :lol:

adidat

 

[CHJ]

Isn't the land generally warmer than the ocean?

That's the reason that the things are calving off more rapidly, the land/sea interface is warming enough to cause the cracks/splits in the continuity of flow that used to keep them attached to the source.

If you fly over them you see that the bulk of the greenland coast is just bare rock, as more and more of it is getting exposed to the the sun rather than having the insulation of snow and ice cover I presume the sea water in contact with the land is rising in temperature, whereas that a few miles out is still cold from the artic stream.

 

[Tom K]

As I understand it this event is part of an annual process where the sea ice melts releasing glacial ice as icebergs. This one is particularly big. It broke along the line of a fissure that has been watched for many years. The sea ice is expected to melt no mystery Roy.

 

[Digit]

Tommo and Chas.
If there is sea ice there then the sea water is well below 0 centigrade, so why is there open water?

Roy.

 

[CHJ]

Tommo and Chas.
If there is sea ice there then the sea water is well below 0 centigrade, so why is there open water?

Roy.

Nope, it's just that most of that sea ice that calves off is up to 600ft thick due to precipitation not freezing sea water, like ice cubes in your drink it takes a while to desolve, The sea is salty so although its colder than the fresh water Ice it remains liquid.

 

[Tom K]

Regine Hock, a glacial geophysicist at the University of Alaska Fairbanks, told the National Geographic that the breakup of ice shelves is "a normal process that happens all the time".

But she said that such a "huge, huge piece of ice … is very unusual".

Its a seasonal thing Roy the ice melts when the weather warms up. I'm sure National Geographic would have picked up on the unusually liquid water in the Nares Straits.

 

[Digit]

Correct me please if I err Chas.
Sea water freezes at minus 2 C +/- about 10%, wave action would lower the required temp further I would suggest, so for sea ice to be there in the Fjord it seems logical that the water temp is well below freezing.
The Petermann glacier is a shallow glacier so the only thing I can think of is that the open water is sun warmed.

Roy.