Lagrangian Modelling
Next to passive tracer transport, chemistry can be considered in Lagrangian models as well. The classical example is a single box chemistry model that is moving along a calculated trajectory. These models are often used with more complete chemistry schemes to foster process understanding. Furthermore, first order decay processes (chemistry or radioactivity) with no interaction between air parcels are commonly implemented in LPDMs. More complex Lagrangian chemistry models need to incorporate inter-particle exchange and need to balance the costs between the number of used air parcels and the complexity of the simulated chemistry.
Models at Empa
Currently the atmospheric modelling group at Empa applies Lagrangian transport models based on three different kinds of meteorological analysis/forecast data.
On the global scale analysis and forecast fields of the operation models of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction (NCEP) are used as input to the trajectory model FLEXTRA and the LPDM FLEXPART. While the trajectory model is mainly used for backward simulations, FLEXPART is used both for backward and forward simulations.
On the regional to continental scale the FLEXPART-COSMO is driven by analysis and forecast fields of the operational numerical weather prediction model COSMO used by the Swiss weather service (MeteoSwiss). Thes model is mainly applied in backward mode.
Online model result browsers:
- Flextra trajectory images computed for Global GAW stations: GAW trajectory image browser
- Global scale FLEXPART results for selected stations worldwide: FLEXPART products browser
- Regional scale FLEXPART-COSMO results for CarboCount-CH sites (combined with observations): CarboCount CH Data Browser
Further reading
- MAIOLICA-II
- CarboCount CH
- NORS
- HALCLIM
- Eyjafjälla eruption
- GEOmon
- FLEXPART-COSMO
- Inverse modeling
- Flow categorisation