Joint meeting RT2B and WP6.2.
Monday 12 November 2007 (1400-1500), Prague
1) Clare Goodess
Tailoring of ENSEMBLES regional climate scenarios outputs to users needs, a questionnaire for
users stakeholders and scenario developers – written up in deliverable D2B.18
The focus of the discussions has been on:

Scenario generator tools and outputs;
Note: it is rather too early for applications users to know what capabilities would be most
appropriate and useful
 What regional data do users need?
- standard surface variables such as: temperature, mean daily precipitation, heat
duration…
- daily and/or sub daily ? - more accent has been put on daily time series output
- 25 km and/or station data

wave
Discussions concerning the format for probabilistic projections:
Possibilities:
- time series;
- PDFs and threshold exceedences;
- maps, percentiles;
- joint probabilities

Recommendations and guidance on methods for the construction of probabilistic regional
climate change projections and their impact modelling – this is a joint RT2B/WP6.2
deliverable – D2B.26/D6.13 – due at month 48.
Remarks:
- will develop the IPCC downscaling guidelines (Mearns/Wilby)
- will provide more illustrative examples of probabilistic output formats
- will aim to integrate existing tools with outputs
- will facilitate data archive access

There are some relevant suggestions from the Lund cross-RT discussions concerning
weighting, ensemble averaging, use of multi-model ensembles
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2) Tim Carter
“LINKING IMPACT MODELS TO PROBABILISTIC SCENARIOS OF CLIMATE CHANGE”
Focus on: a) evaluating impacts on extreme events
b) complex impact model- two approaches, one is a multiple scenarios approach and
the other is a response surface approach.
Response surface approach (e.g., hydrological response) – need to:
- aggregate climate information to basin level
- need climate information to adjust response surfaces
Discussion focused on the joint probability plot (precipitation and temperature) presented by Tim
for a grid box.
WP 6.2 data requirements:
- direct model output as time series
- uncertainty/probabilistic analysis to be undertaking in WP6.2
- some interest in statistically-downscaled information (time series)
Discussions on the type of outputs, format…
- monthly, seasonally or annually averaged multi-model changes by grid box for key driving
variables (commonly temperature and precipitation)
- Joint PDF for key variables may be useful
- Regional averaging of information important for some applications (e.g., river-basin scale)
Clare: joint PDFs could be useful for the impact studies but also regional averages could be
interesting. Perhaps, a catalogue of available climate information could be useful.
Comments:
 Clare: a catalogue of RT2B scenario outputs, including statistical downscaling will be
produced.

Jaime Ribalaygua, Clare, Hans von Storch, Albert Klein-Tank - information for impact
assessment: raises the questions = station data or gridded data? Which is better?
Another problem: format of the data that will be provided for the impacts group people?
Stations or grid level? In which way will the data be provided and also the scale?

The Rockel regions (as used in PRUDENCE) may provide a useful aggregation scale,
e.g., for joint PDFs
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Joint deliverables - proposal for RT2B/WP6.2 collaboration
D6.13/D2B.26- guidelines on use of probabilistic information – due August 2008 – and related
paper (D6.14/D2B.34) due 6 months later (month 54).
Need to decide who is going to contribute to discussions/work.
Meeting Action
Agreed to appoint a data contact person for RT2B (Clare Goodess) and WP6.2 (Stefan Fronzek).
Websites on RCM data availability:
See the RT3 web pages
Also Data section in the RT2B regional scenarios portal – see link from the ENSEMBLES home
page (results section).
Minute taker: Rodica Tomezieu
Editing: Clare Goodess
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