date: Tue Feb  1 16:57:20 2005
from: Phil Jones <p.jones@uea.ac.uk>
subject: Re: SOI and NAO
to: Dennis Shea <shea@cgd.ucar.edu>

    Dennis,
      All is well at home. Hope you're well also and Kevin isn't working you
    too hard - or passing on his troubles due to Landsea. I know he won't
    be but he seems to have been dragged through the mill over it.  At least the
    two of us know what to expect later on in the IPCC process. I hope it
    subsides and doesn't get to Ben Santer and Mike Mann proportions.
    The issue with Mike is about to come to the surface again as a paper
    will appear in GRL saying his curve is all wrong. The new curve is so
    wrong it is unbelievable that even GRL appears to have been nobbled.
      As for Darwin and Tahiti, several years ago I compared the two series
    with what we had, what CPC had then and what the Australians had for
    the two sites. All differences post 1931 probably resulted from this. For
    Tahiti they are small except for 2hPa in 1936. For Darwin, only Sept82
    can be considered large. I did the comparisons with Rob Allan who was
    then at CSIRO (he's now at the HC in Exeter). I think we assumed the
    Australians knew what the number should be.
      I wouldn't have thought that NCEP-NCAR would be good enough to
    resolve small differences. Doubt if ERA-40 would either.
      I do recall doing a little more work on the early years at Tahiti, when
    doing this paper.
    Knnen, G.P., Jones, P.D., Kaltofen, M.H. and Allan, R.J., 1998:  Pre-1866 extensions of
   the Southern Oscillation Index using early Indonesian and Tahitian meteorological
   readings.  J. Climate 11, 2325-2339.
     Maybe that is why there are diffs with CPC and WMSC.   Or maybe someone at CPC
    made some changes.
     Hope this helps.
   At 16:20 01/02/2005, you wrote:

     Hi Phil
     >     don't think anyone answered your email of Dec 20. The person who
     >  responds to cru@uea.ac.uk has been off sick since the New Year.  We think
     >  we've just found some of the emails that have come through.
     I thought something was up. I have asked questions before and
     received replys in prompt fashion.
     >
     >    The base period for the SOI on our web site should be 1951-80.  Are there
     >  any other questions?
     THX ... Not really any specifics
     This was some 'deep infrastructure' work related to
     our section's WWW page: [1]http://www.cgd.ucar.edu/cas/catalog/climind/
     We download the CPC darwin/tahiti every month and we compute the SOI
     using Trenberth (MWR, 1984).
     Kevin wanted a detailed comparison of the CRU and
     our [Climate Analysis Section] SOIs. Part of this
     was a value-by-value check.
     One thing I did was to print out values where the
     differences were >0.2mb
     I was hoping the the World Monthly SFc Station Climatology (WMSC)
     would resolve any major differences. However, Wilbur Spangler
     thought that this was not an independent dataset.
     For more recent data (1950-pres) to possibly help resolve differences,
     I interpolated the SLP given by Reanalysis.
     eg: the 197907 interpolated reanalysis revealed that the CRU was correct.
     Reanalysis showed the value to be approx 1014.? [forget exact number].
     The funny thing to me is that in more recent years,
     sometimes the CRU agrees with WMSC and in other time
     and CPC agrees with the WMSC. Interpolation using reanalysis
     does not help.
     Hope all is well with you and your family!
     Best Regards
     Dennis
                     yyyymm
     (0)     Darwin: 197205  CRU=1012.4  CPC=1013.7  Dif= -1.3 WMSC=1013.7
     (1)     Darwin: 197303  CRU=1007.4  CPC=1007.0  Dif=  0.4 WMSC=1007.0
     (2)     Darwin: 197310  CRU=1009.6  CPC=1010.0  Dif= -0.4 WMSC=1010.0
     (3)     Darwin: 197412  CRU=1006.5  CPC=1006.1  Dif=  0.4 WMSC=1005.6
     (4)     Darwin: 197811  CRU=1009.5  CPC=1009.1  Dif=  0.4 WMSC=1009.5
     (5)     Darwin: 197907  CRU=1014.6  CPC=1011.1  Dif=  3.5 WMSC=1011.1 *CRU [Re]
     (6)     Darwin: 198209  CRU=1014.3  CPC=1014.0  Dif=  0.3 WMSC=1014.3
     (7)     Darwin: 199010  CRU=1011.4  CPC=1010.9  Dif=  0.5 WMSC=1011.4
     (0)
     (0)     Tahiti: 189601  CRU=1010.8  CPC=1011.8  Dif= -1.0 WMSC=1010.8
     (1)     Tahiti: 189602  CRU=1011.7  CPC=1012.7  Dif= -1.0 WMSC=1011.7
     (2)     Tahiti: 189603  CRU=1010.6  CPC=1011.6  Dif= -1.0 WMSC=1010.6
     (3)     Tahiti: 189604  CRU=1010.4  CPC=1011.4  Dif= -1.0 WMSC=1010.4
     (4)     Tahiti: 189608  CRU=1013.1  CPC=1014.1  Dif= -1.0 WMSC=1013.1
     (5)     Tahiti: 189609  CRU=1012.7  CPC=1013.7  Dif= -1.0 WMSC=1012.7
     (6)     Tahiti: 189610  CRU=1012.7  CPC=1013.7  Dif= -1.0 WMSC=1012.7
     (7)     Tahiti: 189611  CRU=1011.2  CPC=1012.2  Dif= -1.0 WMSC=1011.2
     (8)     Tahiti: 189612  CRU=1010.2  CPC=1011.2  Dif= -1.0 WMSC=1010.2
     (9)     Tahiti: 190504  CRU=1010.0  CPC=1008.0  Dif=  2.0 WMSC=1008.0
     (10)    Tahiti: 190505  CRU=1011.0  CPC=1008.1  Dif=  2.9 WMSC=1008.1
     (11)    Tahiti: 190506  CRU=1012.0  CPC=1010.2  Dif=  1.8 WMSC=1010.2
     (12)    Tahiti: 193604  CRU=1014.2  CPC=1012.2  Dif=  2.0 WMSC=1014.2
     (13)    Tahiti: 194012  CRU=1007.5  CPC=1009.5  Dif= -2.0 WMSC=1007.5
     (14)    Tahiti: 195810  CRU=1012.1  CPC=1012.4  Dif= -0.3 WMSC=1012.2
     (15)    Tahiti: 196306  CRU=1013.4  CPC=1013.1  Dif=  0.3 WMSC=1013.3
     (16)    Tahiti: 196903  CRU=1012.6  CPC=1012.3  Dif=  0.3 WMSC=1012.6
     (17)    Tahiti: 197702  CRU=1011.8  CPC=1012.1  Dif= -0.3 WMSC=1011.8
     (18)    Tahiti: 198106  CRU=1014.2  CPC=1014.5  Dif= -0.3 WMSC=1014.2
     (19)    Tahiti: 198109  CRU=1014.8  CPC=1014.5  Dif=  0.3 WMSC=1014.8
     (20)    Tahiti: 198204  CRU=1011.9  CPC=1012.2  Dif= -0.3 WMSC=1011.9
     (21)    Tahiti: 198304  CRU=1011.0  CPC=1010.4  Dif=  0.6 WMSC=1010.4
     (22)    Tahiti: 198411  CRU=1012.5  CPC=1012.8  Dif= -0.3 WMSC=1012.8
     (23)    Tahiti: 199704  CRU=1012.3  CPC=1012.8  Dif= -0.5 WMSC=1012.2

   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.jones@uea.ac.uk
   NR4 7TJ
   UK
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