Reporting period October 2001 - March 2002
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Reporting period October 2001 - March 2002 |
Technical work for the first Work Package (WP1) was undertaken over the period December 2000 to October 2001 and results were presented in two deliverables (D1 and D2) in June 2001 and November 2001 respectively. The objective of WP1 was to consolidate approaches and develop an understanding of the requirements for representing climate change in safety assessments (SA) as perceived by the BIOCLIM participants. This was achieved through the collaboration between the organisations with responsibility for disposing of national radioactive waste and the regulatory agency within the BIOCLIM consortium. Information has been collated and summarised in two separate documents on :
• how climate change
has been treated to date in performance assessments; and
• how present day information and palaeological data on past climate
change can be used as a basis for understanding how climate may affect the biosphere
in the future.
The first document (Deliverable D1) summarises the mechanisms causing climate change, provides a synopsis of how environmental change is currently treated in such assessments, and summarises the lessons learned to date from such applications. The second document (Deliverable D2) provides present day narrative pictures together with palaeological climate and vegetation data for four European regions where deep radioactive disposal sites might be developed. This work will contribute to future Work Packages as a basis for understanding how past climate changes have influenced the current regional biosphere systems in order to lay the basis for modelling how radionuclides might migrate and accumulate in future biosphere systems and climate conditions following release from a repository.
This work has served two main purposes.
First, it has contributed to an understanding of the type of information required
for use in a radiological assessment and the problems associated with trying
to model climate and environmental evolution over very long periods of time.
The information is being used in Work Package 4 to guide approaches to the representation
of long-term climate changes in radiological assessments. Secondly, the information
on past regional characteristics will contribute to future work packages as
a basis for understanding how past climate changes have influenced the current
regional biosphere systems. The present and past data collations will help in
the derivation of downscaling rules to enable regional climate and vegetation
patterns to be derived from global scale modelling.
The technical work of the second Work Package (WP2) is on-going and is scheduled to be completed by April 2003. Results of this work package are to be presented in four documents (Deliverables D3 to D6). Deliverable D3 was delivered in October 2001. The general purpose of WP2 is to develop a hierarchical strategy for representing sequential climate changes in the geosphere-biosphere system. This strategy should cover the time scale relevant to the geological disposal of solid radioactive waste, i.e. typically hundreds of thousands to one million years. Four models are used in the framework of this work package :
• A simple model (the
threshold model developed by LSCE/CEA) and a model of intermediate complexity
(the LLN 2-D NH climate model developed by UCL/ASTR) in order to simulate
climate change over the next one million years.
• A GCM (the LMDz model developed by LMD/CNRS, France but
adapted for BIOCLIM purposes by LSCE/CEA) in order to provide a more detailed
picture of the climate over Europe.
• A regional climate model (the MAR model developed by UCL/ASTR)
to produce estimates of local climate conditions. The results obtained will
be compared with those based on statistical downscaling methods.
First, the climate of the next million years was simulated according to different scenarios for natural and anthropogenic greenhouse gas forcing using both the threshold and the LLN 2-D NH climate models. These models provide the time evolution of continental ice volume over the next one million years, as well as the Northern Hemisphere annual mean temperature over the same period. The results of these simulations have been evaluated and used to identify specific climatic situations of particular interest for studying the impacts of radioactive waste repository sites. More precisely, six epochs have been selected to be further studied using the more detailed models.
Second, a general circulation model (GCM) will be used to provide a more detailed picture of the climate over Europe. The version of the model (ocean + atmosphere/vegetation) to be used has been selected and preliminary simulations (control run) have been performed.
Third, a regional climate model (MAR) will be used to produce estimates of local climate conditions at the selected sites/areas. Preliminary work with the MAR model was undertaken in January 2002. A large domain covering not only Western Europe but also a large part of the North Atlantic, North Africa and Eastern Europe has been selected. The procedure for the transfer of information from the GCM to the MAR model has been tested and a preliminary experiment over the domain and for one month of the present climate condition has been performed.
Fourth, statistical downscaling techniques
will also be used to derive regional information, for comparison with the dynamical
downscaling (i.e., the MAR output) and with the rule-based downscaling
developed in Work Package 3. The GCM variables required as potential predictors
for statistical downscaling have been identified, as have the predictands, i.e.
monthly temperature and precipitation time series for stations in the three
study areas.
The technical work of the third Work Package (WP3) is on-going and scheduled to terminate in April 2003. Results of this work package are to be presented in three documents (Deliverables D7 to D9). The goal of WP3 is to provide long term climatic scenarios for future changes, with simplified, but still physically based models, the so-called "Earth models of Intermediate Complexity", or EMICs. Most of these models are still in development in climate research laboratories, and using them for the BIOCLIM project is an interesting challenge. Progress has been substantial on the two models involved as follows.
• MoBidiC (developed by UCL/ASTR) - The full coupling between the atmosphere/ocean part of the model and the ice sheets has been performed. Preliminary experiments over the last glacial-interglacial cycle are currently on-going. Some further fine-tuning will probably be required. 130kyr of simulation required about two weeks of computation time.
• CLIMBER (developed by PIK, Germany but adapted to BIOCLIM issues by LSCE/CEA) - the coupling between the ocean/atmosphere model and the high resolution ice-sheet model is close to being operational. Some preliminary experiments are still required on crucial steps of the ice-sheet evolution.
Deliverable D7 will provide a detailed description of the development of these models within the BIOCLIM project. A draft version describing the status of the two models is now near completion.
Downscaling - A former version of MoBidiC was used in January to test the procedure for transfer of information from UCL/ASTR to UEA and to test the methodology rules for the downscaling. The next step of this procedure is planned for next autumn when the fully coupled version of MoBidiC will be available for establishing the rules.
The first draft of Deliverable D8
(Development of the rule-based downscaling methodology for BIOCLIM Work Package
3) provided the basis for detailed discussion at the forth progress (January
2002) meeting and has been revised in the light of that discussion. It describes
the 10 steps that need to be followed in order to construct a rule-based downscaling
procedure. Steps 1-4 are complete, or very close to completion. Work started
on step 5 (Identification of appropriate analogue stations to describe each
climate class) in May 2002, and was progressed further at the fith progress
(May 2002) meeting, where steps 6 (Selection of appropriate CLIMBER/MoBidiC
simulations for the identification of downscaling rules/thresholds) and 7 (Identification
of objective rules/thresholds for defining climate classes in CLIMBER/MoBidiC
output) were also discussed. Preliminary discussions have been held on step
8 (Manipulation of analogue station data into an appropriate format for presentation
of results and input to PA).
Technical work on Work Package 4 (WP4) is not scheduled to commence until October 2002. However, it was recognised at the first progress meeting (November 2000) that the amount of work required to complete WP4 was substantial and that there was nothing to preclude an initial phase of the work being undertaken in parallel with the other Work Packages. In view of this, it was decided that development of the methodology to be used in WP4 could begin immediately. Initial thinking relating to the development of such a methodology was included in a discussion document that was presented at the third progress meeting (July 2001). This discussion document was reviewed briefly at the meeting and extensive comments were subsequently received from various BIOCLIM participants. A synthesis of these comments was produced, together with an updated and substantially expanded discussion document. Both the synthesis of comments and the expanded discussion document were reviewed in detail at the forth progress meeting and a small working party was formed to develop the methodological approach to be adopted in WP4. Proposals from this working party have be discussed at the fifth progress meeting and will be further discussed at the six progress meeting, so that detailed technical work on WP4 can start without delay on October 2002.
Work Package 5 activities are associated with the organisation of the final seminar and the production of the seminar proceedings. Discussions have already begun between the ANDRA Project Co-ordinator and the EC representative as to the nature and format of the final seminar. Preliminary discussions with BIOCLIM participants have also been held to get ideas. It may be possible to hold a joint final seminars with other related EC projects that will be completed at the same time as BIOCLIM and that are addressing complementary technical issues. Informal discussions are taking place with other project co-ordinators on this point.
It is a major concern of all participants
that the work of the project should be available to as wide an audience as possible.
Representatives of other organisations have already expressed their desire to
obtain results from the BIOCLIM project.
- " Reporting
period October 2000 - April 2001 "
- " Reporting period April 2001 - September 2001
"
- " Reporting period October 2001 - March 2002 "
- " Reporting period April 2002 - September 2002
"
- " Reporting period October 2002 - December 2003
"
