Monday, June 11, 2012


cc: Gabi Hegerl <>
date: Fri Apr 17 17:09:37 2009
from: Phil Jones <>
subject: Re: input for proposal
to: claudia tebaldi <>, Michael Wehner <>

Claudia, Mike,
I dropped a few of the reply list.
The papers that I've been involved with are these four. I can't see the first
one on the site. I think the fourth may be from the previous project, but
it could be from the first year.
The thrust of my input has been in two areas - the humidity dataset
work (with Nathan). The Nature paper shows that you can
detect and attribute a climate change signal in surface humidity data. It also
shows that this increase in q (specific humidity) is a direct result of
the increase in T. RH stays roughly the same (as a hemispheric average),
which is something climate models have done for ages. So this was an
observational proof of a feature that has been with us for ages.
The J. Climate paper is about the dataset used in the Nature paper.
The Nature Geosciences paper is Nathan's about Arctic and Antarctic temperatures.
This completes the detection and attribution for these areas that were omitted
in Ch 9 of AR4.
The fourth was about a rapid change that occurred in Europe in the first half
of the 18th century, so indicating what is possible from just natural changes in
climate. This was in Task 2.5.
The work I'm currently doing relates to developing a dataset of the Palmer Drought
Severity Index (PDSI) for the world's land areas (except for the Antarctic and Greenland).
Once finished, I'd like to move on to doing some D&A with the dataset.
The rationale for looking again at PDSI was that there were numerous questions
about the metric in the comments on Ch 3 of AR4. PDSI is calculated from
precipitation and potential evapotranspiration (PET). Traditionally PET has been
calculated with the Thornethwaite formula, but hydrologists don't like this. We've
calculated PDSI using both Thornethwaite and a Penman formula (this uses more
than just temperature, including sunshine/cloudiness, vapour pressure and wind).
Hydrologists like this formula, but as PDSI is based 90% on precip, the use of
either formula makes very little difference to large-scale patterns of PDSI.
I still have to write up this PDSI work. I will get there, but there is one paper I
have to do first. The PDSI work is in Task 2.4 or 2.5. The IDAG web page seems
unclear here. I think it should be 2.4.
At 00:02 16/04/2009, claudia tebaldi wrote:

Dear all,
Hope this finds you well.
Michael and I are starting on the new IDAG proposal.
At this time, we need to ask you for a -- hopefully not too time
consuming -- form of feedback:
Could each of you send us -- at the earliest convenience -- a list of
your IDAG-relevant publications, from 2006 to present-day, including
work in press, and a few paragraphs (or a series of bullet points)
summarizing the thrust of your D&A activities since the beginning of
This all will go in the "Scientific Background" section of the new proposal.
Thank you very much from both of us
Claudia & Michael
Claudia Tebaldi
Research Scientist, Climate Central
currently visiting IMAGe/NCAR
PO Box 3000
Boulder, CO 80305
tel. 303.497.2487

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

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