Tuesday, December 20, 2011


From: Caspar Ammann <ammann@ucar.edu>
To: Christoph Kull <christoph.kull@pages.unibe.ch>
Subject: Re: climate reconstruction challenge
Date: Thu, 29 Jun 2006 06:43:40 -0600
Cc: Tim Osborn <t.osborn@uea.ac.uk>, Keith Briffa <k.briffa@uea.ac.uk>

Hi Christoph,
sounds excellent. 20th is a good target with three weeks left. Let me
launch one full round to solicit comments and ideas, and then I can send
you what we have to build the web site. I'll check with Mike about
having him fold this into the report.

Christoph Kull wrote:
> Dear Caspar and Tim,
> Thanks for putting this issue forward!!
> PAGES/CLIVAR may help communicating this challenge to the community.
> We will be able to setup the website with the data sets and the call etc.:
> - let me know what you need! It would be best for us to have first a simple
> "word document with the structure, headings and text. We will then produce a
> "hidden site" that can be updated and finalized before it will go public
> online.
> We will be able to announce the challenge to the community via the
> Newsletter and e-news:
> - we need a respective experiment description.
> - the next Newsletter is going to be published by end of July. Can you
> provide me this information by the 20th? This would also fit with the
> planned announcement in the workshop report for EOS...Mike will draft this
> report.
> I suggest to directly contact him for an incorporation of this call.
> All the best, thanks a lot and greetings from Bern,
> Christoph
> On 23.06.2006 19:23, "Caspar Ammann" <ammann@ucar.edu> wrote:
>> Hi Tim,
>> just back from the various trips and meetings, most recently
>> Breckenridge and the CCSM workshop until yesterday. This coincided with
>> the release of the NRC report...
>> Thanks Tim for getting in touch with Simon and Eduardo. And I would
>> think it would be excellent if you would be on the reconstruction side
>> of things here. We really need to make sure that all the reconstruction
>> groups (the ones that show up in the spaghetti-graph) also provide
>> reconstructions for the Challenge. By the way, Mike Mann is fine with
>> the participation of the german group in this as he has spoken now
>> favorably on the project.
>> I think the separation you point at is absolutely crucial. So, as I
>> indicated in Wengen, I would suggest that we could organize a small
>> group of modelers to define the concepts of the experiments, and then
>> make these happen completely disconnected from standard data-centers. A
>> Pseudo-Proxy group should then develop concepts of how to generate
>> pseudo-proxy series and tell the modelers where they need what data. But
>> what they do is not communicated to the modelers. Based
>> The underlying concept as well as the technical procedure of how we
>> approach the pseudo-proxies should be made public, so that everybody
>> knows what we are dealing with. We could do this under the PAGES-CLIVAR
>> intersection umbrella to better ensure that the groups are held separate
>> and to give this a more official touch. Below a quick draft, we should
>> iterate on this and then contact people for the various groups.
>> So long and have a good trip to Norway,
>> Caspar
>> Here a very quick and simple structural draft we can work from: (all
>> comments welcome, no hesitations to shoot hard!)
>> Primary Goals:
>> - cross-verification of various emulations of same reconstruction
>> technique using same input data
>> - comparison of skill at various time scales of different techniques if
>> fed with identical pseudo-proxy data
>> - sensitivities of hemispheric estimates to noise, network density
>> - identify skill of resolving regional climate anomalies
>> - isolate forced from unforced signal
>> - identify questionable, non-consistent proxies
>> - modelers try to identify climate parameters and noise structure over
>> calibration period from pseudo-proxies
>> Number of experiments:
>> - available published runs
>> - available unpublished, or available reordered runs
>> - CORE EXPERIMENTS OF CHALLENGE: 1-3 brand new experiments
>> ^one experiment should look technically realistic: trend in
>> calibration, and relatively reasonable past (very different phasing)
>> ^one experiment should have no trend in calibration at all, but
>> quite accentuated variations before
>> ^...one could have relatively realistic structure but contains a
>> large landuse component (we could actually do some science here...)
>> Pseudo-Proxies and "instrumental-data":
>> - provide CRU-equivallent instrumental data (incl. some noise) that is
>> degrading in time
>> - provide annually resolved network of pseudo proxies ((we could even
>> provide a small set of ~5 very low resolution records with some
>> additional uncertainty in time))
>> - 2 networks: one "high" resolution (100 records), one "low" resolution
>> (20), though only one network available for any single model experiment
>> to avoid "knowledge-tuning", or through time separation: first 500-years
>> only low-red, then second 500-years with both.
>> - pseudo-proxies vary in representation in climate (temperature, precip,
>> combination), time (annual, seasonal) and space (grid-point, small region)
>> Organization of three separate and isolated groups, and first steps:
>> - Modeler group to decide on concept of target climates, forcing series.
>> Provide only network information to Proxy-Group (People? Ammann, Zorita,
>> Tett, Schmidt, Graham, Cobb, Goosse...).
>> - Pseudo-proxy group to decide on selection of networks, and
>> representation of individual proxies to mimic somewhat real world
>> situation, but develop significant noise (blue-white-red) concepts,
>> non-stationarity, and potential "human disturbance" (People? Brohan,
>> Schweingruber, Wolff, Thompson, Overpeck/Cole, Huybers, Anderson, ...).
>> - Reconstruction group getting ready for input file structures: netCDF
>> for "instrumental", ascii-raw series for pseudo-proxy series. Decide
>> common metrics and reconstruction targets given theoretical pseudo-proxy
>> network information. (People: everybody else)
>> Direct science from this: (important!)
>> - Forced versus internal variations in climate simulations (Modelers)
>> - Review and catalog of pseudo-proxy generation: Noise and stationarity
>> in climate proxy records, problems with potential human/land use
>> influence (Proxy Group)
>> - Detection methods and systematic uncertainty estimates (Reconstruction
>> Group)
>> Tim Osborn wrote:
>>> Hi Caspar and Christoph,
>>> I just wanted to let you know that:
>>> (1) I have emailed Simon Tett (for HadCM3) and Eduardo Zorita (for
>>> ECHO-G Erik-I, not sure about Erik-II) to ask if they would be
>>> prepared for surface temperature fields to be made available from
>>> their model runs and placed on a pseudo-proxy website for use in
>>> pseudo-proxy studies. I'll let you know their response.
>>> (2) In Wengen I suggested that Philip Brohan, a colleague of Simon
>>> Tett, might be interested in creating pseduo-proxies from the output
>>> of Caspar's secret model simulation, because of Philip's interest in
>>> statistical error models (e.g. in the error model he just published of
>>> the instrumental temperature record, HadCRUT3). I have emailed Philip
>>> to ask him if he would be interested. Again, I'll let you know his
>>> response.
>>> With regard to the "climate reconstruction challenge", Keith and I
>>> were wondering how it is going to be run. Obviously some kind of
>>> organising group would be useful to ensure it is designed to be as
>>> scientifically useful an experiment as possible. Yet there needs to
>>> be a clear distinction between provided experimental design advice
>>> (and things like convening EGU sessions) and having too much knowledge
>>> of the setup that would prevent such people from taking part in the
>>> challenge. Keith and I would be interested in the former, but would
>>> also like to keep our distance and take part in the challenge. I'm
>>> not sure that it was clear in Wengen exactly who is to organise this all.
>>> Cheers
>>> Tim
>>> Dr Timothy J Osborn, Academic Fellow
>>> Climatic Research Unit
>>> School of Environmental Sciences, University of East Anglia
>>> Norwich NR4 7TJ, UK
>>> e-mail: t.osborn@uea.ac.uk
>>> phone: +44 1603 592089
>>> fax: +44 1603 507784
>>> web: http://www.cru.uea.ac.uk/~timo/
>>> sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm
>>> **Norwich -- City for Science:
>>> **Hosting the BA Festival 2-9 September 2006

Caspar M. Ammann
National Center for Atmospheric Research
Climate and Global Dynamics Division - Paleoclimatology
1850 Table Mesa Drive
Boulder, CO 80307-3000
email: ammann@ucar.edu tel: 303-497-1705 fax: 303-497-1348


No comments:

Post a Comment