The RMI is providing an operational service on the dispersion modelling of multiple trace gases and other species in the atmosphere.

Within this framework, RMI is participating in the national emergency plan for the management of nuclear and radiological accidents (https://www.nuclearrisk.be/nuclear-emergency-plan), in close collaboration with its partners (crisis center, Belgian nuclear research centre, FANC, IRE, BELVE,...)

RMI is also participating within the Belgian NDC and the BENELUX NDC (national data centre), within the context of the CTBTO.

This service is also focussing on the validation of atmospheric trace gases, retrieved by satellites within the framework of the AC SAF.

The consequenses, related to the volcanic eruption of the Eyjafjallajökull, were a major incentive for the meteorological- and other scientific communities to improve their operational products related to these types of events.

At the RMI, we have set up a strategy to improve our knowledge on aerosols, observed from the surface by setting up a LIDAR network. One of the major problems during this event was the lack of knowledge on the observation of the vertical distribution of aerosols in the atmosphere. Since the installation of our operational LIDAR network, we have the possibility to observe aerosols in the atmosphere.

RMI is also responsible for the calculation of dispersion of suspended nuclear particles. Therefore we have an operational dispersion model at our disposal, which calculates for several hotspots on a daily basis precalculated dispersion maps. We can use the dispersion model also for other types of aerosols and trace gases (e.g.  SO2, see Fig. 1)).

In the weather office, the forecasters can start an "on-demand" dispersion modelling forecast which can be calculated for every location, located on the Northern Hemispere. We can provide a forecast with a lead time of 72 hours.

On 22/09/2014, our Brewer spectrofotometer observed a total column of 7 DU of SO2. This was nicely forecasted by our dispersion model (Figure 1).

Andy Delcloo
Royal Meteorological Institute of Belgium
Ringlaan 3
B-1180 Uccle