Computer Science School
Technical University of Madrid
The EMMA model structure is composed by two blocks: One block is the numerical packages which simulates the three dimensional mesoscale meteorological fields and the chemistry activity in the atmosphere, the second block is composed by the peripherical tools such as: emission, deposition and friendly software interface (tcl/tk). The numerical packages are called: REMEST (based on the MEMO and MM5 models) and CHEMA, the peripherical packages are called EMIMA (emission model for anthropogenic and biogenic sources -it uses the REMO module for landuse types classification-), DEPO for the deposition parameterization of the different pollutants, and the tcl/tk friendly user interface. Recently, we have incorporated a module which is called ASSIMA to take into account the assimilation of the meteorological and pollution data for initial and boundary conditions.
EMMA model is applied over Madrid domain under a nesting structure: EMMA_R and EMMA_U, this approach allows an optimization of the computer resources and also an improving of the spatial resolution over the metropolitan area. The landuse classification is obtained by using LANDSAT-V satellite data (Thematic Mapper) by using a software also developed in the laboratory called REMO. This classification is made over 30 m spatial resolution data and the efective landuse classification is provided oer 250 m spatial resolution. The chemistry solver is based on the SMVGEAR implict scheme. The software tool is called CHEMA and it can be applied over any kind of chemical mechanism. The linkage between the meteorological mesoscale model (REMEST) and CHEMA is made in on-line mode which means that every meteorological timestep (usually 10-40 seconds) the chemistry is solved. The solar radiation and air temperature which is prognostic by the meteorological model is used as input for the CHEMA module so that the kinetic constant and photolisis rates are optimized. The EMMA application over Madrid is using the CBM-IV mechanism.
The traffic emissions are calculated by using the CORINAIR and EPA methodologies. The vehicle distribution for 6 different scenarios have been provided by the Department of Road Construction at the Technical University of Madrid.
The EMMA application includes a friedly software tool EMMA-VIS which has been developed with the tcl/tk tool. Because of the high complextity of the numerical applications (particulary REMEST and CHEMA) the user would require a long period of training to apply EMMA. EMMA is a software application to forecast air quality on real-time so that it is an operational version of the ANA code. The potential user is not intended to be an expert in air quality modelling and on the other hand the application should be run under daily basis. The EMMA-VIS has been built under these assumptions. The software allows to visualize surface concentrations at a specific time of the day and also the user can access to the prognostic concentration at each cell. See an example for the regional domain here. In the case of the urban domain it is also possible to visualize the results (see example). The EMMA-VIS incorporates the capabilities of VIS5D (University of Winsconsin, USA). The user is able to visualize the three dimensional domain for different species at the same time. The operational mode of EMMA is based on the following procedure: the operator should provide at least a vertical meteorological sounding of the area to be studied (additional versions of EMMA are capable to initialize the model by using only surface meteorological data) and also surface air pollution information (generally from the urban and regional air pollution network). This information is provided by the operator from the 24 hours before the actual day (when the simulation is going to be started). This 24 hours of data is treated by the assimilation module (not included in the former version of EMMA) in order to "lunch" the model for the next 96 hours where the real forecasting is produced. The EMMA model has produced valuable results when comparing the prognostic data with the measured data from the monitoring stations. However, the user should be aware about the complexity of such a exercise since the data from the monitoring station is very local and the model data is produced over larger areas and under average basis. The observed data is carrying on fluctuations (which are produced byu the turbulence and by the limitations of the instrument) which should be incorporated into the assimilation module to undertand properly the exercise of comparing predicted with observed data.
The EMMA project has located an EMMA Home Web Site (please, click here to visit) or see some views in this server:
Home page of the Emma Web Site (click here).
Genoa (Italy) map view of curret suphur dioxide concentrations (click here).
Leicester (United Kingdom) map view of nitrogen dioxide concentration 24 h forecast (click here).
Stockholm (Sweden) map view of Particulate Matter concentration 24 h forecast (click here).
Madrid (Spain) map view of Ozone concentration 48 h forecast (click here).
Madrid, July, 1998