from: "Michael Meredith" <mmmatXYZxyz.ac.uk>
subject: Re: SOI during 20th century
One very quick follow-up question, if I may (sorry!)....
Ive done as you suggested, and normalized the Darwin monthly MSLP
data, and it doesnt show much in 1926/7. Neither does Nino3.4.
However, the NOAA CPC SOI index (from
shows quite a decent-sized El Nino in 1926 (plot attached).
I realise it's probably very difficult for you to comment on what NOAA
or might not have done to their numbers, but do you have a feeling for
might be a discrepancy? In your paper you mention offsets applied to
for biasses in different periods - is this a factor?
Apologies for taking up your time, but very grateful for any advice
Dr. Mike Meredith
Head of Atmosphere and Ocean Group
British Antarctic Survey
Cambridge CB3 0ET
>>> Phil Jones <p.jonesatXYZxyz.ac.uk> 06/06/2007 10:56 >>>
An SOI estimate from the Quinn et al chronology is unlikely to
be that reliable. There are other SOI/ENSO indices such
as Nino3.4. Here is a good web site
The MSLP data that goes into the SOI should be fine
in the 1920s. To be perfectly safe go to our web site and get
Darwin MSLP, then calculate an index based on normalized
Darwin monthly (and then multiply by -1).
The SST indices on the site are alternative ENSO measures.
I recall the event in the mid-1920s being quite prominent in some
indices some years ago - but in more recently used series it isn't
At 16:52 05/06/2007, you wrote:
>I was wondering if I could ask your advice about SOI during the 20th
>century. Ive recently been looking at some oceanographic data from
>Southern Ocean collected during the 1920s and 1930s, and (based on
>modern analyses) we know that ocean temperatures here depend on ENSO.
>I was looking at the CRU SOI index
>(http://www.cru.uea.ac.uk/cru/data/soi.htm) to look for such
>relationships in the earlier data also.
>My question is: how reliable are the SOI values for the early part of
>the 20th century? Specifically, around 1925/6/7/8? A different
>seemed to show a very strong El Nino in 1925/6
>presumably this is subjective and questionable?
>If you know of any other analyses that you consider to be robust for
>SOI that covers the 1920s up to present, Id be grateful if you could
>point me in their directions.
>Many thanks for advice
>Dr. Mike Meredith
>Head of Atmosphere and Ocean Group
>British Antarctic Survey
>Cambridge CB3 0ET
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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
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