Process-oriented validation of
coupled chemistry-climate models

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Scientific Topics

Providing accurate and reliable predictions of future changes of atmospheric ozone is of central importance in climate studies. It is important to assess how reliable the current models are and what processes should be included in them. Chemistry-climate interactions are of major significance, because an increase of greenhouse gases and a slow decrease in halogen loading is expected, both influencing the stratosphere and ozone. In recent years a number of chemistry-climate models (CCMs) with different levels of complexity have been developed. They produce, for example, a wide range of results concerning the time and extent of ozone recovery. A scientific discusstion has started to identify the main processes which determine the behaviour of ozone in the atmosphere. The development of data products from ENVISAT provides new information to test the understanding of atmospheric processes and to improve the performance of CCMs.
The aim of the workshop is to identify the key underlying processes that control the future evaluation of the ozone layer, and to find specific diagnostics of these processes. The definition of specific diagnostic tools will facilitate the evolution of complex models such as CCMs. To develop a catalogue of requirements, the following scientific topics, which are of significance with respect to ozone behaviour, will be discussed:

An overview addressing CCM validation and a talk on statistical methods will lead off the workshop.
 

Posters:

It is expected that discusstion and poster presentations will be provided by all participants. The posters will be on display during the entire meeting. Plenty of time is allocated to poster sessions.
Talks:
Each of the main sessions will begin with a 30-minute survey talk, followed by a few short talks chosen from the submitted abstracts. Each survey talk will be based around a central vugraph containing the processes relevant for the corresponding session plus

For Each Process
 

* A specific diagnostic  (for that process)
* Ranking  (meaning how important is that process with respect to stratospheric ozone)
* Uncertainties  (well-known, etc.)
* How can data be used for that diagnostic?  (any requirements?)

The aim is for the survey talks to describe what is needed to validate CCMs, and not to give a review of the state of knowledge in each field. The main part of the talk will be spent adding depth/justification to the criteria list. The short presentations on specific issues will help to develop this list and to provide the basis for the hour of discussion associated with each session as well as the working groups. There is plenty of time allocated for the poster session on the first day.
 

Working Groups:
At the end of the workshop we'll have break-out sessions where people split into working groups (one for each of sessions). The outcome of the working groups of each session will be discussed in the final plenary.
Chairs:
As a lead into the discussion the respective chairs will briefly summarize the key points from the presentations, raise open questions and highlight controversial issues. Rapporteurs will be assigned to each session.
Assessment:
The outcome of the workshop will be a summary of that list published in the SPARC newsletter. Hopefully the workshop will stimulate a new
assessment of coupled chemistry-climate models.