Wednesday, April 25, 2012

3527.txt

cc: John Kennedy <john.kennedyatXYZxyzoffice.gov.uk>, Simon Tett <simon.tettatXYZxyzac.uk>, Susan.Solomon@noaa.gov, Gabi Hegerl <gabi.hegerlatXYZxyzac.uk>
date: Wed, 15 Apr 2009 21:15:33 +0100
from: Thomas Crowley <thomas.crowleyatXYZxyzac.uk>
subject: Re: trends for n. land (summer) vs globe
to: Phil Jones <p.jonesatXYZxyz.ac.uk>

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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.SolomonatXYZxyza.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.crowleyatXYZxyzac.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.
>>> >> 0.8�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.kennedyatXYZxyzoffice.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.jonesatXYZxyz.ac.uk
> NR4 7TJ
> UK
> ----------------------------------------------------------------------------



--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.


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