Julia Slingo and Rowan Sutton of the National Centre for Atmospheric Science, Walker Institute for Climate System Research, University of Reading, have an interesting letter in this week's Nature magazine. They point out that this year's loss of sea-ice cover in the Arctic is unlikely to be explained by temperature change alone. Arctic wind anomolies are implicated as part of a global pattern of exceptional summer circulation.
They conclude:
"The growing La Niña in the East Pacific undoubtedly had a major influence globally, and there is some evidence from past events that La Niña predisposes the circulation towards the type of exceptional patterns seen this summer."
RE Arctic warming - has anyone studied the volcanic activity there? I saw a piece the other day that mentioned tectonic plate action for hundreds of kilometres under the Arctic Ocean and the warming effect this could have.
If only we could get Clive Hamilton and David Marr interested in a REAL example of an attack on free speech......
Neil posted - As readers will see from the last 2 blog entries, comments of a defamatory nature made against organisations or individuals can get the blog owners into legal trouble. We will have to be more vigilant in future -
So let me get this straight. If someone were to defame me over the phone, then I can sue the phone company and/or force them to issue an apology to all their customers?
Horse manure. The proper remedy to being termed a predatory, self-interested, organization is to stop acting like a predatory, self serving, organization.
Their comment on La Nina is very brief:
"These Arctic wind
anomalies were part of a global-scale pattern
of highly unusual circulation this summer,
the causes of which are as yet unclear.
The growing La Niña in the East Pacific
undoubtedly had a major influence globally,
and there is some evidence from past events
that La Niña predisposes the circulation
towards the type of exceptional patterns" END
They're not imputing a direct SST impact, moreover some sort of teleconnection.
I'm not about to hand over USD 18 to read a 78K PDF document so I'll have to wing it.
If I recall correctly, Slingo and Sutton wrote a very good paper about the 2003 summer heatwave in Europe and showed that the dry ground, caused by a drought of several months, was a major influence on temperatures, so I have a lot of time for their ideas.
In this case though NASA has described the situation in this year and last as being due to abnormal winds and I see no good reason to doubt them at this time.
The brief extract from Nature shown here gives no indication of Arctic wind patterns or shifts in high & low pressure cells. Also there's a problem in that the Hadley Cell circulation, which takes heat from the equatorial Pacific to the mid latitudes doe snot reach into the polar regions and requires the "co-operation" of Rossby waves to carry that heat to the Arctic.
In this case the loss of ice was greatest where the oceans bring warm water from the south, i.e. north of Russia and through the Bering Strait. The later is a puzzle because it is not particularly deep at round 500m but then again, the loss of Arctic Ice corresponded pretty well to these shallower regions while ice above the deeper regions tended to remain.
Slingo and Sutton will need to work harder to convince me.
Fair enough.