date: Wed, 06 Jun 2007 17:16:37 +0100 from: "Michael Meredith" subject: Re: SOI during 20th century to: Thanks Phil 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 http://www.cpc.noaa.gov/data/indices/ ) 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 might or might not have done to their numbers, but do you have a feeling for why there might be a discrepancy? In your paper you mention offsets applied to account for biasses in different periods - is this a factor? Apologies for taking up your time, but very grateful for any advice Best wishes Mike *********************************************** Dr. Mike Meredith Head of Atmosphere and Ocean Group British Antarctic Survey High Cross Madingley Road Cambridge CB3 0ET United Kingdom http://www.antarctica.ac.uk/staff-profiles/template.php?user=mmm >>> Phil Jones 06/06/2007 10:56 >>> Michael, 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 http://www.cgd.ucar.edu/cas/catalog/climind/TNI_N34/index.html#Sec5 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 so obvious. Cheers Phil At 16:52 05/06/2007, you wrote: >Hello Phil > >I was wondering if I could ask your advice about SOI during the 20th >century. Ive recently been looking at some oceanographic data from the >Southern Ocean collected during the 1920s and 1930s, and (based on >modern analyses) we know that ocean temperatures here depend on ENSO. So >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 analysis >seemed to show a very strong El Nino in 1925/6 >(http://www.jisao.washington.edu/data_sets/quinn/index2.html), but >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 > >Best wishes >Mike Meredith > > > >*********************************************** >Dr. Mike Meredith >Head of Atmosphere and Ocean Group >British Antarctic Survey >High Cross >Madingley Road >Cambridge CB3 0ET >United Kingdom > >http://www.antarctica.ac.uk/staff-profiles/template.php?user=mmm > > >-- >This message (and any attachments) is for the recipient only. NERC is subject >to the Freedom of Information Act 2000 and the contents of this email and any >reply you make may be disclosed by NERC unless it is exempt from release under >the Act. Any material supplied to NERC may be stored in an electronic >records management system. 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 ---------------------------------------------------------------------------- -- This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system. Attachment Converted: "c:\eudora\attach\noaa_soi.ps"