Wednesday, November 30, 2011


date: Mon Aug 10 09:50:21 2009
from: Phil Jones <>
subject: RE: Proposal as it stands -- now I need your help!
to: "Stott, Peter" <>, "claudia tebaldi" <>, "Myles Allen" <>, "Knutti Reto" <>, "Gabi Hegerl" <>, "Zwiers,Francis [Ontario]" <>, "Tim Barnett" <>, "Hans von Storch" <>, "David Karoly" <>, "Toru Nozawa" <>, "Ben Santer" <>, "Daithi Stone" <>, "Richard Smith" <>, "Nathan Gillett" <>, "Michael Wehner" <>, "Doug Nychka" <>, "Xuebin Zhang" <>, "Tom Knutson" <>, "Tim Delsole" <>, "Jones, Gareth S (Climate Scientist)" <>, "Stephen Leroy" <>, <>

Dear Claudia,
Here are a few thoughts as I'm off for a couple of weeks off from Thursday this week.
We can go with a proposal that is more of the same - more D&A studies with more variables
globally and some getting down to regional scales. My weekend thoughts were that we could
structure the proposal a little differently to try and explain more why temperature seems
to work well, but variables like precipitation and pressure require GCM and RCM output to
be scaled. D&A work began with temperature using monthly gridded datasets at as near to
global scales as obs data allows. We've gone down to the daily time scale with
precipitation and temperature extremes and also gone down to regional space scales for
specific events (like the 2003 European Heat Wave). It is at these regional scales that
most people would like to see AGW explanations of recent changes. It is at these finer
temporal and spatial scales that we need to emphasize in the proposal - something that is
already there in the proposal outline. Reducing the temporal scale to daily limits us due
to data availability, except for some long daily series in a few areas.
My thought is that we need to try to also explain why AGW runs underestimate things for
variables like precipitation and pressure. For precipitation, there are two aspects - the
amounts and also the number of raindays. Monthly gridded precipitation datasets have also
been developed for raindays, so it's possible to also look at amounts per event. Models
probably don't do raindays that well, and there will be issues of comparing point values
which are gridded to boxes, while models do these areas directly. There are also issues of
what threshold for a rainday to use. It would also be possible to look at how the
parameters of say the Gamma Distribution are changing and whether models reproduce these
well or not.
In CRU, we have gridded PDSI series available and a paper soon to be submitted. This
uses a different formulation for the potential evapotranspiration (than the traditional
Thornthwaite) but it doesn't seem to make much difference to first few PCs. So, I'm
suggesting two work tasks, which would be at both the global land scale and also at the
regional land scale.
Using D&A with PDSI. There is quite a bit of number crunching here to get Penman PET
from GCM and RCM output. It's a bit of a hobby horse of mine to get modellers to output
PET, as it is so useful for impacts people.
Using D&A with parameters from the precipitation distribution (mainly monthly, but daily
would be possible where datasets are good enough).
I can sketch out some text for these two, if they are considered useful, and there is a
limit of how much text each sub task requires - I guess not much else the proposal would
get too long.
As for the tasks and sub-tasks already there, I'd like to be involved in the one numbered
1.4 and also the one with Gabi on regional variability over the last millennium (which is
probably just Europe and North America).
1.4 requires these noise-reduction techniques (taking out ENSO, volcanoes and circulation
influences a la
Dave Thompson) to be applied to GCMs as well. Worth trying at the global and hemispheric
scale first.
I'm not saying we shouldn't continue to go down the operational D&A route, but we do try
and need to explain why temperature works well on all space and temporal scales but precip
and pressure require considerable scaling. I've no ideas on what to do about pressure.
At 11:46 04/08/2009, Stott, Peter wrote:

Dear Claudia,
I'm off on vacation tomorrow and therefore somewhat stretched for a very
considered response from me - sorry - but the items I have my name
against look fine to me. There are a couple of items I couldn't find
which we could offer something up if we think appropriate
- attribution of ocean changes including temperature, salinity and sea
level rise to include new datasets, model analyses and methodologies
(could include Ben, Tim, Peter, ...) to answer questions such as can we
close sea level budget, can we better determine planetary radiative
imbalance ...
- hydrological cycle changes using new techniques, datasets (eg salinity
in addition to ocean analyses if we can use them), models etc to
attribute greenhouse gas and aerosols on hydrological cycle changes and
determine whether (as has been suggested) models generally underestimate
observed hydrological cycle changes, both means and extremes (could
include Myles, Peter, Francis ? ...)
I liked the
"Critical review of methods used for proposed operational attribution
bullet. I think it would be good if IDAG could provide an assessment of
proposed methodologies and what would need to be done/satisfied for
output to be reliable, robust and timely. Along these lines we have
planned a BAMS paper which I was in line to lead. This might takes us a
bit of the way if we can get the people involved in this development
actively engaged in such a paper. Right now a many-author many-viewpoint
BAMS paper sounds a bit of a daunting prospect but maybe it will seem
more achievable after a break.
Finally I've attached the WIRE article I submitted yesterday by Stott,
Gillett, Hegerl, Karoly, Stone, Zhang, Zwiers (form some reason the
submission page only allowed me to enter 2 names in the relevant field,
hence only the first two appear on the covering page). This is one of
IDAG's paper deliverables I think (?).
All the best with getting the proposal off,
Dr. Peter Stott
Head, Climate Monitoring and Attribution,
Met Office Hadley Centre, Fitzroy Road, Exeter. EX1 3PB, UK
Tel +44(0)1392 886646 Fax +44(0)1392885681
-----Original Message-----
From: [[2]] On
Behalf Of claudia tebaldi
Sent: 31 July 2009 19:51
To: Myles Allen; Knutti Reto; Stott, Peter; Gabi Hegerl; Zwiers,Francis
[Ontario]; Tim Barnett; Hans von Storch; Phil Jones; David Karoly; Toru
Nozawa; Ben Santer; Daithi Stone; Richard Smith; Nathan Gillett; Michael
Wehner; Doug Nychka; Xuebin Zhang; Tom Knutson; Tim Delsole; Jones,
Gareth S (Climate Scientist); Stephen Leroy;
Subject: Proposal as it stands -- now I need your help!
Dear all
please find attached the current version of the IDAG proposal. Please
disregard the format of the reference list for now, I'm going to work on
the cosmetics later (but feel free to add to that as you see fit).
I wish I knew exactly when the deadline for submitting this was, but
meanwhile, could I ask you for some specific input and some more general
feedback at your earliest convenience, and please *****no later than
August 20th?*****
Here at first is a specific list :
1) Those of you in charge of the specific tasks that were highlighted at
the meeting (you know who you are) could you please look at the
task/subtask list and clean it up/flesh it out/make it a little more
coherent? Add or take out as you see fit!
2) All of you: could you sign up for specific subtasks and give me an
idea of a 3-yr timeline for these activities that you would like to
follow? Please iterate with the heads of the task for this if you need
to work something out...
3) All of you fully funded, please send me a brief bio-sketch -- and
whatever you gave Gabi in the past in terms of financial information for
the funds you need, could you please send it on to me, updated?
Then a more general list:
I would REALLY REALLY appreciate it if you all read the 'thing' and made
comments/added/corrected as you see fit (of course with track changes
on!). I rather have too much and work on shedding than have gaping
holes in this narrative.
Everybody that recognizes his/her work in the Scientific background
section: would you please paste in a figure (and a description) to make
this think less black and white?
I hope this is not too much to ask on this fairly short timeline, I
really need some help here at this point. And help means both addition
to and refurbishing of what's in there but also checks and, by all
means, corrections.
Thank you very much in advance, and please let me have something within
the deadline!!!
Hope you are all having a good summer (and this does not spoil it!)
best to all
Claudia Tebaldi
Research Scientist, Climate Central
currently visiting Stanford University,
Department of Statistics
tel. 650 796 6974
cell 303 775 5365

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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