Thursday, March 15, 2012


cc:, Matilde Rusticucci <>, Phil Jones <>, Peter Lemke <>, Jurgen Willebrand <>, Nathan Bindoff <>, zhenlin chen <>, Melinda Marquis <>
date: Tue, 09 Jan 2007 13:48:26 -0700
from: Susan Solomon <>
subject: Re: IPCC WG1 Observations Conference Call
to: Kevin Trenberth <>, Brian Hoskins <>

Thanks Brian and Kevin for the help.

I agree with Brian about reversing the order in the headline sentence but agree with Kevin
that a separate bullet is most helpful. I suggest we keep the headline short and simple
and just leave the language we have about wind patterns being one of several things
changing there. Otherwise it could be read as putting the circulation change into a very
high prominence in the headline which isn't quite the emphasis we were discussing, I

I tried to combine the suggestions and to keep things clear enough that governments won't
complain about lack of specifics. If you look over the comments, you will have seen that
above all they will not tolerate vague language. Anybody who was in Shanghai (or any
other IPCC meeting) can attest to that so please please everybody help make things as
specific as we can.

So my suggestion for the wind pattern bullet is:

Mid-latitude westerly wind speeds have increased in both hemispheres since about the
1960s. This has caused storm tracks to move towards higher latitudes. {3.6}

Regarding the headline that proceeds it, can we consider something like this:

At continental or ocean basin scales, numerous changes in climate have been observed.
These include sea ice extent, precipitation amounts, ocean salinity, wind patterns, and
[aspects of extreme weather] OR [the frequency of heavy precipitation and of heat waves,
the intensity and duration of drought, and the intensity of hurricanes and typhoons.]

The ice sheets have been taken out of the above because they are moving to a consolidated
sea level subsection, to deal with several requests for that.

Is the new option after wind patterns too specific? I am a little concerned that we will
be challenged on that. We could keep what we have: 'aspects of extreme weather'. Equally,
I am worried that they will challenge the vagueness of 'extreme weather' so that is why you
see two alternatives here.



At 8:54 AM -0700 1/9/07, Kevin Trenberth wrote:

Hi Brian
Do you need the first part? Are you rewriting the headline on SPM p 5 lines 35-37 or
are you adding an extra bullet on circulation?
I thought we agreed on the latter, but your piece seems more like the former.
If we left the headline alone and added:

* Changes in large-scale atmospheric circulation are apparent and, in particular, the
mid-latitude westerly winds have shifted polewards and strengthened, altering storm

would be an alternative approach. I think it is helpful to mention storm tracks but not
be specific about how they have changed.
What do you think?
Brian Hoskins wrote:

Headline 2
I suggest the following:
At continental or ocean basin scale, numerous changes in climate have been observed.
Mid-latitude westerly winds (and the associated storms) have shifted polewards and
strengthened. Other climate changes include precipitation,.....
I have taken the suggestion form SPM_327 to reverse the order of the first sentence.
The westerly winds sentence is essentially that in a headline in the TS.
I should much prefer not to include the bracketed itallicised phrase on storms. The
evidence is less strong. There is some evidence for reduced numbers of storms also but
no room to say that. It was not headlined in the chapter or the TS.
Best wishes

Kevin E. Trenberth e-mail: [1]
Climate Analysis Section, [2]
P. O. Box 3000, (303) 497 1318

Boulder, CO 80307 (303) 497 1333 (fax)
Street address: 1850 Table Mesa Drive, Boulder, CO 80305

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