Friday, December 23, 2011

1199994210.txt

From: Peter Thorne <peter.thorne@metoffice.gov.uk>
To: Dian Seidel <dian.seidel@noaa.gov>
Subject: Dian, something like this?
Date: Thu, 10 Jan 2008 14:43:30 +0000
Cc: Ben Santer <santer1@llnl.gov>, Tom Wigley <wigley@cgd.ucar.edu>, Karl Taylor <taylor13@llnl.gov>, Thomas R Karl <Thomas.R.Karl@noaa.gov>, John Lanzante <John.Lanzante@noaa.gov>, Carl Mears <mears@remss.com>, "David C. Bader" <bader2@llnl.gov>, "'Francis W. Zwiers'" <francis.zwiers@ec.gc.ca>, Frank Wentz <frank.wentz@remss.com>, Leopold Haimberger <leopold.haimberger@univie.ac.at>, Melissa Free <melissa.free@noaa.gov>, "Michael C. MacCracken" <mmaccrac@comcast.net>, Phil Jones <p.jones@uea.ac.uk>, Steve Sherwood <Steven.Sherwood@yale.edu>, Steve Klein <klein21@mail.llnl.gov>, 'Susan Solomon' <ssolomon@al.noaa.gov>, Tim Osborn <t.osborn@uea.ac.uk>, Gavin Schmidt <gschmidt@giss.nasa.gov>, "Hack, James J." <jhack@ornl.gov>

All,

as it happens I am preparing a figure precisely as Dian suggested. This
has only been possible due to substantial efforts by Leo in particular,
but all the other dataset providers also. I wanted to give a feel for
where we are at although I want to tidy this substantially if we were to
use it. To do this I've taken every single scrap of info I have in my
possession that has a status of at least submitted to a journal. I have
considered the common period of 1979-2004. So, assuming you are all
sitting comfortably:

Grey shading is a little cheat from Santer et al using a trusty ruler.
See Figure 3.B in this paper, take the absolute range of model scaling
factors at each of the heights on the y-axis and apply this scaling to
HadCRUT3 tropical mean trend denoted by the star at the surface. So, if
we assume HadCRUT3 is correct then we are aiming for the grey shading or
not depending upon one's pre-conceived notion as to whether the models
are correct.

Red is HadAT2 dataset.

black dashed is the raw data used in Titchner et al. submitted (all
tropical stations with a 81-2000 climatology)

Black whiskers are median, inter-quartile range and max / min from
Titchner et al. submission. We know, from complex error-world
assessments, that the median under-cooks the required adjustment here
and that the truth may conceivably lie (well) outside the upper limit.

Bright green is RATPAC

Then, and the averaging and trend calculation has been done by Leo here
and not me so any final version I'd want to get the raw gridded data and
do it exactly the same way. But for the raw raobs data that Leo provided
as a sanity check it seems to make a miniscule (<0.05K/decade even at
height) difference:

Lime green: RICH (RAOBCORE 1.4 breaks, neighbour based adjustment
estimates)

Solid purple: RAOBCORE 1.2
Dotted purple: RAOBCORE 1.3
Dashed purple: RAOBCORE 1.4

I am also in possession of Steve's submitted IUK dataset and will be
adding this trend line shortly.

I'll be adding a legend in the large white space bottom left.

My take home is that all datasets are heading the right way and that
this reduces the probability of a discrepancy. Compare this with Santer
et al. Figure 3.B.

I'll be using this in an internal report anyway but am quite happy for
it to be used in this context too if that is the general feeling. Or for
Leo's to be used. Whatever people prefer.

Peter
--
Peter Thorne Climate Research Scientist
Met Office Hadley Centre, FitzRoy Road, Exeter, EX1 3PB
tel. +44 1392 886552 fax +44 1392 885681
www.metoffice.gov.uk/hadobs


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