crandles wrote:
>In the absence of a better model
Where would you start? Is it unreasonable to start with saying the most
important variable not considered in the above analysis is the
thickness of the ice. That is important because of its affect on the
ratio of surface area to volume.
http://www.boincforum.info/boincuser/Crandles/ArcticIceThickness.PNG
http://www.boincforum.info/boincuser/Crandles/arcticIceVolume.PNG
Does that have any effect on your estimate of the fair price of the
claim?
As you know, these graphs are taken from Maslowski's presentation.
http://www.ametsoc.org/atmospolicy/documents/May032006_Dr.WieslawMaslowski.pdf
He seems to think that about half the loss of sea-ice extent is the
result of the inflow of warm water from the Pacific. He mentions that
there is no inflow thru the Fram Strait, which I understand to be the
result of outflow of surface water and also a major flow of sea-ice
during the winter months.
There is an inflow of water from the Atlantic, but it is not on the
surface. There may also be inflows thru the Barents Sea, which one
might expect to increase as the area of open water increases and the
wind stress tends to push the surface water towards the east. Both of
these inflows fron the North Atlantic could result in increased
production of brine enriched sinking under the Arctic sea-ice, as the
yearly variation in sea-ice increases. These sinking waters would
eventually exit the Arctic as a bottom current thru the Fram Strait and
as flow off the shelf below the Barents Sea, thence into the GIN seas.
An increase in these flows would be consistent with the measured
increase in salinity of waters flowing over the Scotland/ Farroe sill.
Look at the lovely map on page 7 of Maslowski's presentation.
The process described above is different from that previously noted as
the THC in the open waters of the GIN and Labrador Seas. There may be
an ongoing shift in the location of the THC from the North Atlantic to
the Arctic, with a resulting shift in the energy flow from warming the
atmosphere to a direct warming/melting of Arctic sea-ice in winter. An
indicator of this could be the change in the character of the sea-ice
along the northeast coast of Greenland.
Whether the inflows from the Pacific discussed by Maslowski or the
inflows from the Atlantic (or both) are a major factor in the loss of
sea-ice is certainly a subject for study and debate. That break point
in the trend for sea-ice volume shown about 1998 might just be a sign
of the "tipping point" that is mentioned so frequently these days.
If so, we've already gone past it.
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