Dr. Moussiopoulos reported then on the status of the various subproject tasks emphasising that the workshop offers a unique chance for establishing cooperations among task team members. Moreover, he stressed the importance of properly defining the links to other subprojects of EUROTRAC-2. In this context, he welcomed the formation of the so-called "meta"-project to host all major urban scale European campaigns (including BERLIOZ, ESCOMPTE and PIPAPO). SATURN will actively contribute to this "meta"-project in view of the comprehensive urban scale campaigns planned in the subproject. Moreover, SATURN will be among the main users of the data sets to result from the various campaigns to be organised. Therefore, it will be important to define conditions and rules for the usage of campaign results. This is among the important aims of the "meta"-project. Dr. Finn Palmgren, the leader of the SATURN Main Group on experimental activities (SATURN-EXP) accepted to represent SATURN in the Steering Group of the "meta"-project.
Another very promising new development within EUROTRAC-2 is the decision to set up the Milan task force with the aim to better organise all experimental and modelling activities related to the air pollution situation in Milan. The task force coordinator Dr. Giovanna Finzi reported that at least five EUROTRAC-2 subprojects plan activities related to Milan: AEROSOL, GENEMIS-2, GLOREAM, LOOP and SATURN. First discussions have already proved that there is a large potential for cooperation within the task force, with obvious benefits for EUROTRAC-2 as a whole.
The next four sessions of the workshop dealt with the four Main Groups (MG) of activities. Each of these sessions started with an introductory talk by the respective MG leader. Several oral presentations and the posters displayed highlighted the progress in the four MGs. Én each of the sessions sufficient time was devoted to discussion, which proved to be very fruitful. Pre-nominated rapporteurs summarised the proceedings in each session.
An important achievement of the Hamburg workshop was the re-organisation of SATURN-MOD. In particular, the contents of tasks MOD2 and MOD3 were modified and a new task leader for MOD3 was appointed (see below). Most of the time of the SATURN-MOD session was devoted to the so far progress and the coordination needs in the four individual tasks.
Concerning task MOD1 (local scale model development), the task team members are almost the same as in the Training and Mobility of Researcher (TMR) programme TRAPOS (Optimisation of Modelling Methods for Traffic Pollution in Streets). Planning has been good and the action is well organised. However, there have been problems in finding young scientists, which would have sufficient experience. SATURN participants were therefore urged to suggest sufficiently experienced young scientists for the vacant posts in TRAPOS (details in www.dmu.dk/AtmosphericEnvironment/trapos).
To promote coordination in task MOD2 (urban scale model system development), it was suggested to subdivide models developed in SATURN into specific categories. In this context, a model inventory is in preparation, based on the questionnaire action which was launched during the EUROTRAC-2 Symposium and is expected to be completed before the end of 1998. This inventory will be accessible through the Internet. Moreover, discussions took place regarding the cooperation between SATURN and GLOREAM. As a conclusion, good-quality individual work is in progress in this task, but despite the so far efforts a more efficient cooperation will be needed in future.
Regarding task MOD3 (scale interactions in models and numerical simulations), there was agreement that this action has not been working as efficiently as it should, in spite of the fact that scale interactions and numerical problems have been investigated separately for each modelling system. It was noted that the relationships of this action with MOD2 have not been sufficiently clear so far. Given, however, the similarity of the scaling, nesting and numerical problems for the various modelling systems, it was decided to maintain this task, though after some restructuring and with Dr. P. Sahm as the new task leader. For the task to be successful, it will have to be coordinated more actively in future.
One of the main objectives of task MOD4 (modelling of aerosols and chemical transformation) is to provide aerosol and chemical modules to be applied in SATURN-MOD as a whole. A questionnaire action organised by the new task leader is expected to provide insight on the status of the individual contributions. In the workshop it was noted that links to other EUROTRAC-2 projects are particularly important for MOD4. Common areas were identified in particular with CMD, GLOREAM, GENEMIS and AEROSOL. In a separate informal MOD4 meeting a more efficient exchange of information and e-mail networking were agreed upon.
Oral presentations in the modelling session dealt with several aspects of ongoing modelling work in SATURN. The first presentation addressed the traffic induced flow and dispersion phenomena inside a vehicle tunnel and street canyon (Jicha). Various numerical results on the flow patterns were presented, including concentration distributions and turbulence in a street canyon, and the role of traffic induced turbulence was discussed. Another talk dealt with multiscale air pollution modelling (Sahm). Model scaling was discussed and an overview of OFIS was presented, a model designed for assessing ozone exposure and abatement strategies. The modelling system contains detailed chemistry and transport models, operated in a compressed procedure allowing low computer costs (details in web page http://aix.meng.auth.gr/lhtee/ofis/). In a further presentation the dynamical core of the MITRAS model was presented (Knoth). The numerical procedures and problems in the context of this microscale model were addressed. Finally, subgrid-scale dispersion and chemical processes in the vicinity of NOx emission sources were addressed (Coppalle). The methods to allow for subgrid-scale transformation of nitrogen oxides were discussed, in particular embedding plume model computations within grid Eulerian models. As a complement to the oral presentations, eight posters were displayed highlighting additional results of modelling work.
The overall impression from the session on model development was that
most individual contributions have progressed well, but only a few effective
cooperations have been launched so far. A regular information exchange
between the Subproject Coordinator, the Main Group leader and the task
leaders was considered to be a prerequisite for enhancing the cooperation
between individual groups.
The objectives of SATURN-VAL were outlined at the previous SATURN workshop as the development and provision of a framework for validating urban scale models. This is being accomplished by four tasks: the development of an evaluation strategy (VAL1), definition of specifications for data relevant to model evaluation, e.g. data generally relevant for evaluation work (VAL2), harmonisation of urban emission inventories (VAL3) and hosting model validation exercises (VAL4).
Previously this MG included the provision of laboratory data for comparison with other results. This activity, which was seen as being dominated by the provision of wind tunnel experimental results, has now been transferred to a more appropriate location within SATURN-EXP.
The SATURN-VAL session was structured along the lines of the relevant work packages:
An extensive inventory of data sets originally produced by COST615 was described together with some simple categorisation of the data sets (Britter). Data may arise from (i) an air pollution monitoring network, (ii) a specific air pollution monitoring campaign, (iii) a field experiment involving controlled releases and (iv) laboratory experiments. As an alternative approach, data sets may be categorised by the model they would be used to evaluate. This could lead to the categories (i) evaluation of full operational air quality models, (ii) evaluation on a modular approach and (iii) evaluation depending on the scale (regional, regional-urban interaction, urban plume). The link between models, the purposes and the appropriate data sets has still not been clarified. This type of work is a precursor to the development of general model evaluation protocols.
The presentation and communication of data sets for validation purposes through electronic media was convincingly demonstrated (Leitl) and the extensive quality control concerns required for archived reference data addressed. The requirements for validation data (Schatzmann) was provided in a paper rather than a presentation. The generation of extensive laboratory data for validation purposes was ongoing, including concentration flux data (Simoens) and with very specific attention to the detail required for validation purposes (Leidtke). As already stated above, these activities will in future be the subject of task EXP3.
As an example for work on urban emission inventories, the generation and quality control of emissions in the Lisbon Region were addressed (Tchapal) including a comparison between top-down (based on fuel consumption) and bottom-up (based on daily NOx emissions form local and line sources) approaches.
Furthermore, a model intercomparison exercise of an academic nature was proposed by JRC (Thunis/Cuvelier). It is suggested that mesoscale models be applied on idealised geographical scenarios, basically two mountains near a sea-land boundary. Three releases are to be considered and both qualitative and statistical intercomparisons will be made.
The amount and quality of activity within VAL was reassuring. In the broadest sense the model evaluation involves the interaction between models and data sets through a protocol with appropriate communication within and without the evaluation. The presentations addressed models and/or data sets and protocols on the mesoscale, the microscale and emissions. However, evaluation of operational air quality models, roughness parameterised models or the intermediate models appear lacking. The importance of communication through electronic media was strongly made.
Two related activities are the questionnaire on experimental data sets for model validation initiated in EXP (Palmgren) and the categorisation of models in MOD2. Some consensus among VAL, MOD and EXD will be required.
Two final points were that attention might be given to a need to state the expected performance measures for an operationally relevant data set. Then, if this measure was met, what can be explicitly and unambiguously said about the applicability or validity of the model. In other words what is meant by a "valid" or "not a valid model".
There was also felt that there was a need for an "urban" model comparison
or intercomparison exercise at a scale smaller than the mesoscale.
In his introduction, the MG leader reviewed the current state of the EXP activities and noted that overall the Group was making good progress. The changes in the MG structure were presented (EXP2 and EXP3 merged into a new EXP2 task, "new" EXP3 led by Dr. Bernd Leitl to deal with wind tunnel studies). Furthermore, it was emphasised that there is a need for a coordinated approach to developments of data sets required for modelling and validation. A short summary was given about the results of the data set inventory carried out in March 1998. The information is available for all PIs and it is planned to integrate this inventory with the model inventory carried out at the University of Hamburg in order to be accessible through the Internet.
Subsequently, reports on the progress in the individual tasks were given. In particular, it was recognised that work on local scale measurements (task EXP1) was making good progress. It was noted that all the partners were in fact making measurements on local and urban scales and that all PIs were involved with particle experiments. Although the 3 PIs were liaising well, a new collaborative project on field measurements of fine particulates was proposed. Four partners had shown interest in becoming involved in this project, and other research groups were encouraged to participate. This will enable closer-working links not only between the individual partners of EXP1 but also between the individual EXP tasks. In addition, this will provide a more effective way of creating data sets for local and urban scales. Again it was emphasised that MOD and VAL should have closer discussions with EXP on development of data sets. It was also noted that EXP1 had a particular relationship with a Training and Mobility of Researcher (TMR) programme TRAPOS dealing with street level air pollution and collaboration was encouraged.
Instead of a summary on urban scale field campaigns (new task EXP2), the main contributions were given during the oral presentations about the campaigns in Graz, Austria (Almbauer) and Milan (Finzi). Additional information referred to the Lisbon campaign (Borrego). Data from these campaigns are available.
As already stated above, a report on the progress of laboratory experiments, primarily of wind tunnel studies (new task EXP3) was given in the VAL session.
Work on particle measurements (task EXP4) was found to progress very satisfactorily. Among the 6 PIs of this rather large task, some were also involved with modelling of particulates and this provided an opportunity to foster closer links with modellers. A key objective of the research activities was to conduct measurements sufficiently detailed to enable source apportionment studies and characterisation of the particles, including fine as well as ultra-fine particles.
Specific achievements in EXP were highlighted in the oral presentations included in this session. To start with, details were provided on a planned campaign for VOC and particulate measurements in local and urban scales (Sokhi). Some preliminary results were reported on the work. Approximately £100K had been spent on acquiring equipment for the trials.
The next presentation outlined the extensive measurements being made on several air pollutants including NOx, O3, SO2, TSP and BTX at roof level and street level (Palmgren). In addition measurements were being conducted of meteorological parameters and of traffic flows. Results exhibiting correlations between the pollutants were shown and a methodology for deriving emission factors by air quality, traffic and meteorological data and inverse application of OSPM, was presented.
Subsequntly, details on the DATE programme involving trace element measurements were given (Almbauer). Results from summer and winter campaigns in Graz were presented. This campaign has resulted in an extensive data set.
The Augsburg campaign aiming at the evaluation of an urban emission inventory was the subject of a guest contribution (Blank). Methodologies were presented allowing for quick, detailed and very detailed approaches for setting up such an inventory.
Moreover, results from detailed measurements of black carbon were shown which revealed that this fraction consisted of mainly the very fine particles, i.e. those smaller than 2.5 microns (Pakkanen). Correlation between NO and NO2 was observed and points to traffic being the major source.
Finally, a short presentation was given on the use of remote sensing for determining surface heat flux (de Ridder). The results indicated good agreement between the model results and those from remote sensing.
Additional experimental work in SATURN was the subject of eight posters.
The major issue related to SATURN-INT in the Hamburg workshop was the re-definition of the individual tasks. First of all, the difference between INT and the other MGs was underlined: The latter generally consider specific items within the overall subject of air quality in urban areas, whereas integration considers combinations of models, monitoring, emission data etc. As such, SATURN-INT is expected to provide the vehicle by which developments within the other three main group areas can be most readily assessed by policy makers or end users.
In the special case of INT1 (the Framework Project) integration represents the bringing into a common framework all work conducted/systems developed under SATURN and communicating such an extensive range of knowledge to the wider user community. Developments over the past year in this area include a ‘Framework Questionnaire’ which was distributed to SATURN PIs to determine how they see their work linking in with other tasks and how their work could be applied or incorporated into systems for end users. As part of the dissemination of information to the wider community a ‘workshop’ of SATURN software will be held at the 1999 SATURN workshop. The intention is to invite influential end users such as those responsible for environmental policy in major cities or representatives of Environmental Agencies. Finally a web site for SATURN-INT is shortly to be launched.
The other three tasks of INT are closely connected; in order to appropriately
distinguish them, in the workshop it was decided to re-define them as follows:
INT 2 Combinations of different components of an air quality management
system (eg modelling and monitoring), but not a complete system.
INT 3 Air quality management systems (AQMS) and Decision Support Systems
(DSS).
INT 4 This refers specifically to aspects of AQMS which calculate population
exposure, health effects, economic impacts or cost benefits of various
scenarios, however it does not include work specifically aimed at developing
air quality standards.
The above new definitions constitute a clarification of previous task
descriptions and in the case of INT4 an increase in scope. Of the
three tasks (INT2-4), most activity over the last year has been in INT3
where the 8 contributions covering a range of developments of air quality
management systems are all proceeding well. As also elucidated in
the frame of oral presentations, these projects cover integration of a
wide range of models and data acquisition systems. Such systems were developed
for particular areas, e.g. the Milan project, to flexible software designed
to be used for a range of cities (ADMS-Urban, AIRQUIS), to flexible software
for particular urban areas (URBIS in Leiden). A further activity
in this area has been a discussion aimed at developing a generic and widely
acceptable description for the structure of an air quality management system
or decision support system.
At the end of the INT session Dr. Dick van den Hout presented first
results of the recent survey related to the Framework Project. This
first stage had focussed on clarifying the internal framework within SATURN.
The aims of the various activities were about equally distributed
between on the one hand the development of techniques and insight in processes
and on the other hand air quality assessment, forecasting, scenario analysis
and the decision making process. Although many interactions between the
contributions existed, only a few contributions aimed to deliver its results
to parallel SATURN contributions. In the following period, it is intended
to arrange contacts with representatives of city authorities, and to invite
these to SATURN meetings, if possible (depending on the funding possibilities)
on a regular basis.
Subsequently, the four rapporteurs gave their reports on the MOD, VAL, EXP and INT sessions. A general discussion followed which turned out to be lively and very fruitful. It mainly aimed at (i) identifying the needs for effective collaboration between the four MGs and (ii) formulating the main conclusions of the workshop. The latter may be summarised as follows:
Model development. The overall impression from the modelling session was that most individual contributions have progressed well, so that the target of defining reasonable model hierarchies will soon be met. Yet, more and closer cooperations will be needed in forthcoming steps of the project. In particular, a regular information exchange between the subproject coordinator, the MG leader and the task leaders was considered to be a prerequisite for enhancing the cooperation between individual groups. E-mail networking should be used as widely as possible for improving coordination and internal dissemination of information within the modelling tasks. Model harmonisation is undoubtedly an important secondary aspect of model inter-comparisons like those planned in the frame of SATURN.
Model evaluation. A considerable progress was noted in setting up evaluation procedures. Furthermore, there seems to be a satisfactory development in producing validation data sets both from wind tunnel experiments and measurements in local/urban scale environments. The combined use of wind tunnel information and street canyon measurements constitutes a first promising attempt towards model evaluation at the local scale. The MESOCOM model intercomparison launched by JRC is expected to lead to a better understanding of the capabilities of urban scale flow and dispersion models.
Experiments. Activities at the local scale benefited much from the close relationship to the TMR project TRAPOS. Moreover, urban scale campaigns were successfully executed in Milan, Lisbon and Graz. Yet, the need was recognised to strengthen the internal collaboration between individual experimental subgroups. The proposed new collaborative project on particles is expected to help in forging closer ties between the individual subgroups.
Integration. Several groups are progressing in the development of urban air quality management systems, including more advanced ones which calculate population exposure, health effects, economic impacts or cost benefits of various scenarios. In general, SATURN is characterised by a high potential for application and therefore it will be important to find ways for an active dissemination of information about the subproject in order to stimulate the exploitation of its results by air quality authorities.
General issues. In later phases of the subproject it will be essential to establish and maintain dense links between the various MGs, in particular MOD, EXP and VAL. As already noted in the 1st Workshop, the success of SATURN will to a large extent depend on the QA/QC measures applied to ensure the validity of the scientific results. In this context it is very positive that the subproject started with a reasonable first approach towards quality assurance planning. An important milestone for the months to come will be the preparation of the Annual Report 1998.
The workshop closed with the announcement that the 3rd SATURN Workshop
will take place in Aveiro, Portugal on 23 and 24 August 1999.
