date: Fri, 17 Apr 2009 19:07:06 +0100 from: Thomas Crowley subject: Re: trends for n. land (summer) vs globe to: Phil Jones Quoting Phil Jones : Phil, thanks for your thoughts - guarantee there will be no dirty laundry in the open. still thinking about relative worth, letting it simmer a few more days. enjoy, gabi is off with the boys camping while I try to get a few things done here. tom > > Tom, > As long as you omit issues of offsets and don't suggest the SST recently > might be wrong. > > Worth getting Gavin Schmidt to read it through as well. > > Cheers > Phil > > > At 17:13 16/04/2009, you wrote: >> Phil >> >> its hard to believe the nh land record is off - so the 1.5 C >> warming is still significant - and the global temp. record is being >> cited a zillion times - so as long as I keep it at that level, I >> don't understand why there should be a problem - especially if I >> cut out or minimize any discussion about offsets in the latter part >> of the record - doesn't that seem a little worthwhile, given the >> fixation on global temps. rather than land temps? tom >>> >>> Tom, >>> I wouldn't bother posting this on Real Climate. >>> Cheers >>> Phil >>> >>> >>> At 21:15 15/04/2009, you wrote: >>>> Quoting Phil Jones : >>>> >>>> >>>> I don't want to be posting something on RealClimate.org that is going >>>> to create confusion rather than clarification. >>>> >>>> should I just not submit the piece after all? >>>> >>>> tom >>>> >>>> >>>>> >>>>> John, >>>>> Another possible issue is the 61-90 ship based SST normals >>>>> for the SH oceans in the range 40-60S. I presume you're working on >>>>> improving these for the next version. >>>>> >>>>> Cheers >>>>> Phil >>>>> >>>>> >>>>> At 12:10 15/04/2009, John Kennedy wrote: >>>>>> The ARGO data don't go into SST analyses at the moment. They do make >>>>>> measurements at depths that overlap with the deeper ship-based >>>>>> measurements, so there's no reason why they couldn't be included in the >>>>>> future or used as an independent validation of the SST data once the QC >>>>>> issues are sorted out. >>>>>> >>>>>> Drifting buoys measure SSTs about 0.15C cooler than ships (with some >>>>>> geographic variation) probably due to predominantly warm biases in the >>>>>> ship data. They are included in SST analyses - more than 85% of all SST >>>>>> observations now come from buoys - and have probably led to a slight >>>>>> underestimate in the rate of warming since the late 1970s when they were >>>>>> first introduced. >>>>>> >>>>>> John >>>>>> >>>>>> On Fri, 2009-04-10 at 22:29 +0100, Simon Tett wrote: >>>>>>> I don't think ARGO goes into the SST dataset though there are >>>>>>> a lot more >>>>>>> buoys in it. When I was at the Hadley Centre we wondered if buoys were >>>>>>> causing a slight cooling trend. [John Kennedy CCed might have some more >>>>>>> thoughts on that.] >>>>>>> >>>>>>> Simon >>>>>>> >>>>>>> Susan.Solomon@noaa.gov wrote: >>>>>>>> Tom >>>>>>>> The fact that land could be shown to be warming more than ocean was a >>>>>>>> major conclusion of the AR4. >>>>>>>> >>>>>>>> It's good to see the update to 2008. Quite striking. >>>>>>>> >>>>>>>> I hate to say this, but I wonder if some of the recent behavior is >>>>>>>> spurious - the Argo floats just don't seem very consistent with >>>>>>> earlier >>>>>>>> records not only for surface temperature but also for sea level (ie >>>>>>>> subsurface). What do you think? >>>>>>>> Susan >>>>>>>> >>>>>>>> >>>>>>>> ----- Original Message ----- >>>>>>>> From: Thomas Crowley >>>>>>>> Date: Friday, April 10, 2009 6:10 am >>>>>>>> Subject: trends for n. land (summer) vs globe >>>>>>>> >>>>>>>>> Hi, >>>>>>>>> >>>>>>>>> I am in the process of producing a new, long (733-1960) paleo >>>>>>>>> reconstruction at annual resolution for purposes of better >>>>>>>>> validation >>>>>>>>> against models. since tree rings are most sensitive to summer half- >>>>>>>>> year >>>>>>>>> temperatures, and trees usually grow on land, I am calibrating >>>>>>>>> against >>>>>>>>> 30-90N summer (land), using HadCRU data updated through 2008, >>>>>>>>> kindly >>>>>>>>> provided by Phil. >>>>>>>>> >>>>>>>>> some interesting items jump out from just comparing (attached) the >>>>>>>>> instrumental reconstructions for 30-90N land, summer vs global >>>>>>>>> temps >>>>>>>>> (anomalies based on 1960-1990 mean for each data set): >>>>>>>>> >>>>>>>>> 1) the n summer land changes are almost twice as large (1.5 vs. >>>>>>>>> 0.8°C) >>>>>>>>> as the global - this is not surprising because we know that land >>>>>>>>> heats >>>>>>>>> up faster than ocean, but the magnitude is quite striking. >>>>>>>>> >>>>>>>>> 2) since most people still live on land, this means the human >>>>>>>>> impact >>>>>>>>> factor has been twice as large as normally assumed for close to 3 >>>>>>>>> billion people >>>>>>>>> >>>>>>>>> 3) the divergence between northern land and global temps seems to >>>>>>>>> be >>>>>>>>> increasing - both record show the recent decrease in temperatures, >>>>>>>>> but >>>>>>>>> on land it only started last year (2008) >>>>>>>>> >>>>>>>>> 4) seven large volcanic eruptions can easily be identified in the >>>>>>>>> northern land record - this again makes sense from an energy >>>>>>>>> balance >>>>>>>>> viewpoint, as summer temperatures are more driven by thermodynamics >>>>>>>>> than >>>>>>>>> dynamics, so the signal is more easily detectable, especially given >>>>>>>>> the >>>>>>>>> added impact of maximized reflection of insolation due to high sun >>>>>>>>> angle. >>>>>>>>> 5) this suggests that northern hemisphere land (summer) might be >>>>>>>>> the >>>>>>>>> most logical data set to look at for detection of volcanic signals. >>>>>>>>> as >>>>>>>>> I have nearly finalized the new paleo reconstruction of volcanos, >>>>>>>>> it >>>>>>>>> might be interesting to re-apply detection and attribution to the >>>>>>>>> new, >>>>>>>>> longer, and (hopefully improved) data sets. >>>>>>>>> >>>>>>>>> fyi, Tom >>>>>>>>> >>>>>>>>> -- >>>>>>>>> The University of Edinburgh is a charitable body, registered in >>>>>>>>> Scotland, with registration number SC005336. >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>> -- >>>>>> John Kennedy Climate Monitoring and Research Scientist >>>>>> Met Office Hadley Centre FitzRoy Road Exeter EX1 3PB >>>>>> Tel: +44 (0)1392 885105 Fax: +44 (0)1392 885681 >>>>>> E-mail: john.kennedy@metoffice.gov.uk http://www.metoffice.gov.uk >>>>>> Global climate data sets are available from http://www.hadobs.org >>>>> >>>>> 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 >>>>> ---------------------------------------------------------------------------- >>>> >>>> >>>> >>>> -- >>>> The University of Edinburgh is a charitable body, registered in >>>> Scotland, with registration number SC005336. >>> >>> 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 >>> ---------------------------------------------------------------------------- >> >> >> -- >> The University of Edinburgh is a charitable body, registered in >> Scotland, with registration number SC005336. > > 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 > ---------------------------------------------------------------------------- -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.