Thursday, December 29, 2011

1409.txt

cc: t.osbornatXYZxyz.ac.uk
date: Mon, 7 Sep 2009 00:13:56 +0100 (BST)
from: "Tim Osborn" <t.osbornatXYZxyz.ac.uk>
subject: New Zealand summer temps
to: p.jonesatXYZxyz.ac.uk

Hi Phil,

just a quick Q before I go to bed!

I've just updated the IPCC paleo chapter Southern Hemisphere plot where we
showed, amongst other things, Ed Cook's New Zealand TRW reconstruction,
with CRUTEM2v Jan-Mar smoothed temperatures.

For my update I've used CRUTEM3v, expecting them to be rather similar but
with a few more years on the end.

But the pre-1930 temperatures are now very different, being much cooler
(by > 0.5 degC for a 25-year low-pass mean) in CRUTEM3v than CRUTEM2v.
Previously they had been, on average, near or even above the 1961-1990
mean, now they're at -0.5 degC.

Is this a result of some homogenization work on New Zealand summer temp
data? Or just some random artefact of minor changes somewhere?

Cheers

Tim

--
Dr. Tim Osborn
RCUK Academic Fellow
Climatic Research Unit
School of Environmental Sciences
University of East Anglia
Norwich NR4 7TJ, UK
www.cru.uea.ac.uk/~timo/

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