EUCAARI model intercomparison of BL nucleation parameterizations

As part of the EU FP6 EUCAARI European Aerosol Integrated Project, BL nucleation was added to the GLOMAP-mode model as incorporated in the UM and simulations carried out to investigate the role these nucleation processes play in determining the properties of European aerosol.

As part of the EUCAARI project, a major field campaign took place in May 2008, and an unprecedented network of aerosol supersites (the EUSAAR network) were employed to measure in detail aerosol size distribution and composition.

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.

Shown here are comparisons of the high temporal resolution data from these four size-resolved aerosol models against observations at the Hyytiala sites in Finland.