date: Mon Apr 28 13:14:35 2008 from: Phil Jones subject: Re: FW: Talk on Understanding 20th C surface temperature to: "Sear, Chris (CEOSA)" , "David Parker" , "John Kennedy" Chris, David Thompson is giving a talk here tomorrow on this. The essence of his talk will be in Nature in a few weeks time. The skeptics will make a meal of this when it comes out, but if they did their job properly (I know this is impossible!) they would have found it. It relates to a problem with SST data in the late 1940s. The problem will get corrected for at some point. SSTs need adjusting as there must be from buckets for the period from Aug45 by about 0.3 gradually reducing to a zero adjustment by about the mid-1960s. The assumption was that after WW2 they were all intake measurements and didn't need adjusting. This will reduce the 1940-1970 cooling in NH temps. Explaining the cooling with sulphates won't be quite as necessary. It won't change century-scale trends. There is much more of an interesting thing going on now. With all the drifters now deployed measuring SST, the % of ships making measurements in now only about 40% of the total - whereas it was all in the late 1990s. In comparisons over the last 10 years it seems that ships measure SSTs about 0.1-0.2 higher than the drifters/buoys. As the 61-90 base period is ship based, it means recent anomalies are colder than they should be (by about 0.1 for global mean T in the last 2 years). Working on a press release with MOHC about the Nature paper. We've been though page proofs with Nature, but these don't yet include figs. I can send these when we get them. Cheers Phil At 12:55 28/04/2008, Sear, Chris (CEOSA) wrote: David, John, Phil Do you know and can comment on this work? Ta Chris -----Original Message----- From: McCloghrie, Paul (CEOSA) Sent: 28 April 2008 12:51 To: Sear, Chris (CEOSA) Subject: FW: Talk on Understanding 20th C surface temperature variability Might be of interest if you're in Cambridge. I did some work with David Thompson years ago and he was doing time series analysis back then too! Paul -----Original Message----- From: Leverhulme Climate Symposium [[1]mailto:climate@esc.cam.ac.uk] Sent: 28 April 2008 11:58 To: climate@esc.cam.ac.uk Subject: Talk on Understanding 20th C surface temperature variability Dear Colleagues, David Thompson of Colorado State University will be speaking in Cambridge on 22 May on 'Understanding 20th century surface temperature variability'. His talk will 'highlight a glaring but previously overlooked error in the time series of global-mean temperatures', see full abstract below. (For those too far from Cambridge to attend, this is for information and interest). The prevailing view of 20th century temperature variability is that the Earth warmed from ~1910 to 1940, cooled slightly from ~1940 to 1970, and warmed markedly from ~1970 onward. In this talk I will exploit a physically-based filtering methodology which provides an alternative interpretation of 20th century global-mean temperature variability. The results clarify the consistency between the century- long monotonic rise in greenhouse gases and global-mean temperatures, provide new insights into the climatic impact of volcanic eruptions, and highlight a glaring but previously overlooked error in the time series of global-mean temperatures. Thursday 22 May, 2.15 pm in Meeting Room 2, Centre for Mathematical Sciences (between Clarkson and Madingley Roads) Department for Environment, Food and Rural Affairs (Defra) This email and any attachments is intended for the named recipient only. If you have received it in error you have no authority to use, disclose, store or copy any of its contents and you should destroy it and inform the sender. Whilst this email and associated attachments will have been checked for known viruses whilst within Defra systems we can accept no responsibility once it has left our systems. Communications on Defra's computer systems may be monitored and/or recorded to secure the effective operation of the system and for other lawful purposes. 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 ----------------------------------------------------------------------------