cc: k.heywood@uea.ac.uk date: Fri Jun 27 12:14:13 2008 from: Phil Jones subject: Re: SST Undergraduate Dissertation to: John.Matthews@uea.ac.uk Robin, Our links are back. [1]http://www.cru.uea.ac.uk/cru/data/temperature/ and the last linked document at the bottom of the page, 17Mb. Cheers Phil Robin, Happy to do this, but there are a number of papers you ought to read. I'll give you a few links to look at. We have been doing a lot of work in this area over about the last 25 years. The CRU web site seems to be down, so I'll send one link later when it's back. There shouldn't be much of a difference between ERSST and HadSST2. I suspect some of the differences you've noticed relate to whether bucket-type corrections were incorporated or not, or whether there were recent changes made to incorporate satellite measurements. It is important to get version numbers on these datasets. You mention various types of buckets, however most measurements now (at least since the 1950s) have been made using engine intakes and insulated buckets. The paper I've attached is the latest one on the Hadley Centre dataset. This shouldn't be that different from HadISST, but the latter is spatially infilled, so it can be used for driving GCMs. HadISST is Rayner et al. (2003) in the atatched. What Rayner et al 2006 have done is the generally accepted adjustments that have to be made. Versions of ERSST have also had these adjustments made. There is a new version of ERSST due out very soon in J. Climate by Smith and Reynolds. What you'd need to do in a project would be to get the raw measurements for the ship track you followed from ICOADS. [2]http://icoads.noaa.gov/ . Worth getting the air temperatures as well, as they have a different set of problems. With data from the 1970s onwards the raw values should include the measurement method. There will also be loads of drifters in the region in recent years and maybe some fixed buoys. These measure SSTs slightly different from ships. ICOADS is all unadjusted (i.e. as measured data). What would be a useful aspect to look at is the recent problem of fewer ship obs and many more drifting buoys. Attached is a paper that mentions this in its final sentence, and a ppt from John Kennedy at the Met Office. All issues with SSTs can generally only be solved with large sample numbers, so the numbers of obs you have are unlikely to be enough, hence my suggestion to get the ICOADS data. Cheers Phil At 16:48 26/06/2008, you wrote: Dr Jones, I am a final year ENV student in Geophysical Sciences and have just returned from my year abroad in North America (at the University of British Columbia, UBC). Over the past six weeks I have been on a research cruise across the central equatorial Pacific from Tahiti to Hawaii. I will be using the data I collected along the ship's transect for my undergraduate dissertation. I wish my final year project to be around the theme of comparing different historical methodologies of measuring Sea Surface Temperatures (SSTs). Originally I planned to do a climate modelling project under Dr Tim Lenton. I wish to contribute to the debate surrounding whether global warming is more likely to lead to El Nino-like or La Nina-like conditions in the tropical Pacific. It has been noted that the NOAA ERSST and the UK Hadley Centre HadISST datasets show opposite and incompatible trends in SST for this region over the past century. It has been suggested that the main discrepancies between these two records (which occur around the 1930s and 1980s) could be the result of methodological changes in SST measurement. I understand that you have been involved with correcting SST records for historical changes in measurement techniques. The abstract for the research paper I completed on ship is attached. I was taking measurements of the temperature of surface seawater sampled in wood, canvas and Zubrycki buckets. The purpose was to discover whether the different bucket types (all used historically for SST measurements) would influence the SST recorded. My contact at UEA with regards this project has been Dr Karen Heywood. Whilst she is willing to act as my supervisor, perhaps you would be more suitable due to your previous research experience on this topic. I will not be returning to UEA until the start of the autumn semester (around September 22nd), but wish to work on my project in the meantime. My UEA advisor is Dr Jenni Barclay. Thanks for your time, Robin Matthews 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 ----------------------------------------------------------------------------