On 16/06/17 00:09, Alastair wrote:
On Thursday, 15 June 2017 20:29:44 UTC+1, Graham P Davis wrote:
On 15/06/17 18:02, N_Cook wrote:
On 15/06/2017 17:08, JohnD wrote:
See that there's some speculation that we might be heading for
the lowest sea ice extent _maximum_ in the recent record (at
least as far as the first (July) max of the year is concerned -
last year the second (Nov) max was no greater than the first).
See eg:

https://sites.google.com/site/arctis...t_byyear_b.png






I read this piece today
https://www.theguardian.com/world/20...m-temperatures




Wednesday 14 June 2017 10.00 BST Last modified on Wednesday 14 June 2017
22.00 BST

Scientists in Canada have been forced to abandon an expedition to
the Hudson Bay to research the impact of climate change, after
warming temperatures created perilous ice conditions off the
coast of Newfoundland.

In late May, 40 scientists from five Canadian universities set
off from Quebec City on the icebreaker and Arctic research vessel
CCGS Amundsen. The expedition was the first leg of a four-year,
C$17m research project designed to delve into the effects of
climate change on Hudson Bay. Cold snap: massive iceberg just off
coast draws Canadians eager for close-up

The icebreaker was soon diverted. Dense ice – up to 8 metres
(25ft) thick – had filled the waters off the northern coast of
Newfoundland, trapping fishing boats and ferries.

“It was a really dramatic situation,” said David Barber, the
expedition’s chief scientist. “We were getting search and rescue
calls from fishing boats that were stranded in the ice and
tankers that were stranded trying to get fuel into the
communities. Nobody could manage this ice because it was far too
heavy to get through.”

Barber, a climate change scientist at the University of Manitoba,
and the other scientists did what they could to help the Coast
Guard rescue the vessels and carved a path for the tankers. They
also took the time to study the ice that surrounded them,
discovering that much of it was the multiyear ice typically seen
in the high Arctic.

It was an unexpected find, said Barber, given the time of year
and how far south they were. “It’s not something you would expect
to see there and not something we’ve seen there before,” he said.
“In the high Arctic, climate change is causing the ice to get
thinner and there to be less of it. What that does is that it
increases the mobility of ice.”

The decision to cancel the first leg of the expedition was made
after it became clear that continuing north would interrupt
search and rescue operations and probably put lives at risk.
Arctic stronghold of world’s seeds flooded after permafrost
melts Read more

The irony was not lost on Barber. “We’re doing a large-scale
climate change study and before we can even get going on it,
climate change is conspiring to force us to cancel that study.”

The decision was a costly one, as the project had already spent
hundreds of thousands of dollars getting the scientists and their
gear on the vessel. The next leg of the expedition, scheduled to
start on 6 July, is expected to go ahead, but the study will
probably need to be extended by at least six months and may
require more funding, he said. “It’s a real mess.”

Barber – who has spent decades researching the impact of climate
change on sea ice – described his week spent on the frontlines of
battling a changing climate as a stark reminder of the reality
the world is facing. “We’re very poorly prepared for climate
change,” he said. “We pay lip service to the fact that we think
we know it’s coming and society is trying to grapple with the
complexity of it, but when it really comes down to brass tacks,
our systems are ill prepared for it.”


I read about this elsewhere and it made no sense to me at all but
this version clears it all up. Thanks!

The problem with the article I read was that they'd made no
reference to multiyear ice. The source for this old ice could have
been from last summer's break up in the Canadian Archipelago but I
suspect that it is ice that has been feeding through the gap
between Greenland and Ellesmere Island.

When I worked in the Met Office's Ice Unit (1965-73) Kane Basin
was covered with fast ice all year round. Now, it not only contains
broken ice during the summer but also right through the winter,
allowing the multiyear ice to move south through the channel
throughout the year. During my time in the Ice Unit, the only time
I knew there would have been multiyear ice in the area was when the
ice in Baffin Bay failed to melt one summer and so became multiyear
ice with the onset of winter.


The passage from the Arctic Ocean to Baffin Bey is called Nares
Strait after Captain Nares
https://dawlishchronicles.com/so-muc...oceanographer/

There is an interesting description of the physics of the strait
he
https://icyseas.org/2014/09/21/a-sho...trait-physics/

What I have noticed is that the melt of Baffin Bay can begin at the
southern end of Nares Strait and then spread south! I am now guessing
that the strong brine from brine rejection,
https://en.wikipedia.org/wiki/Brine_rejection , flows under the Nares
ice and melts the fresher ice in Baffin Bay.


Thanks for the name of the Strait, Alastair, I only remembered the name
of the basin to the south of it.

When I was producing ice charts back in the late 60s, I saw that in
northern Baffin Bay, south of Kane Basin, there was often an area that
was ice-free or that was covered by thin ice. This area showed up even
in the depths of winter. One theory was that it was due to upwelling of
warmer waters but I realised that it could be explained simply by the
pack-ice being driven SSW by the strong and persistent winds in the
area. The rate of movement of the ice matched the rate at which theory
said it would move relative to the strength of the wind. The ice was
continually being blown away from the area and, during the winter, being
replaced by newly-formed ice. Thus, during the spring thaw, this area
was the first to be relatively free of ice.

As I said, the situation has changed since then. At that time, Kane
Basin and Nares Strait remained frozen from shore to shore every year.
Now, the ice appears mobile through much of the year, even in the middle
of winter.

In addition to what you noticed about the melting south of Nares Strait,
the breakup often occurs to the north of it. I was looking at one chart
for Jan 31st this year and the Strait appeared mostly ice-free (though
it is probably covered by thin, new ice that the satellite can't see).
In many such pictures, there is also an area of very broken ice north of
the Strait with a roughly semi-circular edge to the more compact polar
ice This shows where the strong current mentioned in your second link is
dragging the polar ice away from the main pack and accelerating it
towards - and through - the strait.


--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
Web-site: http://www.scarlet-jade.com/
Never approach a bull from the front, a horse from the rear,
or an idiot from any direction! [Irish proverb]