date: Fri, 17 Apr 2009 19:07:06 +0100
from: Thomas Crowley <thomas.crowley@ed.ac.uk>
subject: Re: trends for n. land (summer) vs globe
to: Phil Jones <p.jones@uea.ac.uk>

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Quoting Phil Jones <p.jones@uea.ac.uk>:

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 <p.jones@uea.ac.uk>:
>>>>
>>>>
>>>> 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 <thomas.crowley@ed.ac.uk>
>>>>>>>> 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.
>>>>>>>>> 0.8C)
>>>>>>>>> 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.


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