from: Tom Wigley <wigleyatXYZxyzr.edu>
subject: Re: 1940s
to: Phil Jones <p.jonesatXYZxyz.ac.uk>
Re increase after 1949, I should have remembered this. It has the same
effect, but better. I'll send you some ENSO out results later -- I do
it as in my GRL paper, ENSO and volcs out together iteratively, and
252-month (maybe 251) running removals. This makes a difference. Re the
ppt, which is NH and which is SH? Also, what is the gray "uncorrected"
line in the other plot? This is the raw data?
Can I use the data in your ppts? Just for the globe. I'm thinking that
the new values will be out before my work is done, and it will really
help to get a head start. Do you have numbers?
Phil Jones wrote:
> A few thoughts
> This is a link to the longer Thompson et al paper. It isn't yet out in
> final form - Nov09 maybe?
> is a link to wattsupwiththat - not looked through this apart from a
> quick scan. Dave Thompson just emailed me this over the weekend and said
> someone had been busy! They seemed to have not fully understood what
> was done.
> Have looked at the plots. I'm told that the HadSST3 paper is fairly
> near to being submitted, but I've still yet to see a copy. More SST data
> have been added for the WW2 and WW1 periods, but according to John
> Kennedy they have not made much difference to these periods.
> Here's the two ppts I think I showed in Boulder in June. These were
> from April 09, so don't know what these would look like now. SH is on
> the left and adjustment there seems larger, for some reason - probably
> just British ships there?
> Maybe I'm misinterpreting what you're saying, but the adjustments
> won't reduce the 1940s blip but enhance it. It won't change the 1940-44
> period, just raise the 10 years after Aug 45.
> I expect MOHC are looking at the NH minus SH series re the aerosols.
> My view is that a cooler temps later in the 1950s and 1960s it is easier
> to explain.
> Land warming in the 1940s and late 1930s is mainly high latitude in NH.
> One other thing - MOHC are also revising the 1961-90 normals. This will
> likely have more effect in the SH.
> With the SH around 1910s there is the issue of exposure problems in
> Australia - see Neville's paper.
> This shouldn't be an issue in NZ - except maybe before 1880, but could
> be in southern South America. New work in Spain suggest screens got
> renewed about 1900, so maybe this happened in Chile and Argentina, but
> Mossmann was head of the Argentine NMS so he may have got them to use
> Stevenson screens early.
> Neville has never been successful getting any OZ funding to sort out
> pre-1910 temps everywhere except Qld.
> Here's a paper in CC on European exposure problems. There is also one
> on Spanish series.
> At 06:25 28/09/2009, Tom Wigley wrote:
>> Here are some speculations on correcting SSTs to partly
>> explain the 1940s warming blip.
>> If you look at the attached plot you will see that the
>> land also shows the 1940s blip (as I'm sure you know).
>> So, if we could reduce the ocean blip by, say, 0.15 degC,
>> then this would be significant for the global mean -- but
>> we'd still have to explain the land blip.
>> I've chosen 0.15 here deliberately. This still leaves an
>> ocean blip, and i think one needs to have some form of
>> ocean blip to explain the land blip (via either some common
>> forcing, or ocean forcing land, or vice versa, or all of
>> these). When you look at other blips, the land blips are
>> 1.5 to 2 times (roughly) the ocean blips -- higher sensitivity
>> plus thermal inertia effects. My 0.15 adjustment leaves things
>> consistent with this, so you can see where I am coming from.
>> Removing ENSO does not affect this.
>> It would be good to remove at least part of the 1940s blip,
>> but we are still left with "why the blip".
>> Let me go further. If you look at NH vs SH and the aerosol
>> effect (qualitatively or with MAGICC) then with a reduced
>> ocean blip we get continuous warming in the SH, and a cooling
>> in the NH -- just as one would expect with mainly NH aerosols.
>> The other interesting thing is (as Foukal et al. note -- from
>> MAGICC) that the 1910-40 warming cannot be solar. The Sun can
>> get at most 10% of this with Wang et al solar, less with Foukal
>> solar. So this may well be NADW, as Sarah and I noted in 1987
>> (and also Schlesinger later). A reduced SST blip in the 1940s
>> makes the 1910-40 warming larger than the SH (which it
>> currently is not) -- but not really enough.
>> So ... why was the SH so cold around 1910? Another SST problem?
>> (SH/NH data also attached.)
>> This stuff is in a report I am writing for EPRI, so I'd
>> appreciate any comments you (and Ben) might have.
> Prof. Phil Jones
> Climatic Research Unit Telephone +44 (0) 1603 592090
> School of Environmental Sciences Fax +44 (0) 1603 507784
> University of East Anglia
> Norwich Email p.jonesatXYZxyz.ac.uk
> NR4 7TJ