EUCAARI model intercomparison of BL nucleation parameterizations

As part of the EU FP6 EUCAARI European Aerosol Integrated Project, UKCA simulations were carried out to investigate the role these nucleation processes play in determining the properties of European aerosol.

The EUCAARI project revolved around a major field campaign in May 2008 together with a new network of aerosol supersites (the EUSAAR network) were employed to make detailed measurements of aerosol size distribution and composition.

As part of a joint EUCAARI-AEROCOM model intercomparison around nucleation processes, UKCA-UM simulations were carried out with GLOMAP-mode coupled to the UKCA StdTrop-Aerchem chemistry and the UM winds and temperatures nudged towards ECMWF operational re-analysis fields for the year 2008.

The model was set to output the model tracers at the surface interpolated to each of the EUSAAR sites at each model timestep thus enabling high temporal resolution evaluation of the size-resolved aerosol and composition from UKCA against the detailed observations from EUCAARI.

Equivalent runs were also carried out with the GLOMAP-mode scheme driven by offline-oxidants in the TOMCAT chemistry transport model -- and by parallel runs with the more sophisticated GLOMAP-bin scheme. A regional aerosol model PMCAMx-UF (Spyros Pandis) was also run in a similar fashion.

Here we show this EUCAARI-AEROCOM model intercomparison of the high temporal resolution data for the concentration of all-partcles (N3) and particles larger than 100nm (N100) from these four size-resolved aerosol models against observations at the Hyytiala sites in Finland.