Parameterization of vertical diffusion and the atmospheric boundary layer height determination in the EMEP model 1Meteorological and Hydrological Service of Croatia, Zagreb, Croatia
2Andrija Mohorovičić Geophysical Institute, Department of Geophysics, Faculty of Science, University of Zagreb, Zagreb, Croatia
3Norwegian Meteorological Institute, Oslo, Norway
Received: 06 March 2009 – Published in Atmos. Chem. Phys. Discuss.: 16 April 2009 Abstract. This paper introduces two changes of the turbulence parameterization for the
EMEP (European Monitoring and Evaluation Programme) Eulerian air pollution
model: the replacement of the Blackadar in stable and O'Brien in unstable
turbulence formulations with an analytical vertical diffusion profile
(K(z)) called Grisogono, and a different mixing height determination, based on
a bulk Richardson number formulation (RiB). The operational or standard
(STD) and proposed new parameterization for eddy diffusivity have been
validated in all stability conditions against the observed daily surface
nitrogen dioxide (NO2), sulphur dioxide (SO2) and sulphate
(SO42−) concentrations at different EMEP stations during the year
2001. A moderate improvement in the correlation coefficient and bias for
NO2 and SO2 and a slight improvement for sulphate is found for the
most of the analyzed stations with the Grisogono K(z) scheme, which is
recommended for further application due to its scientific and technical
advantages. The newly extended approach for the mechanical eddy diffusivity
is applied to the Large Eddy Simulation data focusing at the bulk properties
of the neutral and stable atmospheric boundary layer. A summary and
extension of the previous work on the empirical coefficients in neutral and
stable conditions is provided with the recommendations to the further model
development. Special emphasis is given to the representation of the ABL in
order to capture the vertical transport and dispersion of the atmospheric
air pollution. Two different schemes for the ABL height determination are
evaluated against the radiosounding data in January and July 2001, and
against the data from the Cabauw tower, the Netherlands, for the same year.
The validation of the ABL parameterizations has shown that the EMEP model is
able to reproduce spatial and temporal mixing height variability.
Improvements are identified especially in stable conditions with the new ABL
height scheme based on the RiB number.
Revised: 18 December 2009 – Accepted: 22 December 2009 – Published: 18 January 2010
Citation: Jeričević, A., Kraljević, L., Grisogono, B., Fagerli, H., and Večenaj, Ž.: Parameterization of vertical diffusion and the atmospheric boundary layer height determination in the EMEP model, Atmos. Chem. Phys., 10, 341-364, doi:10.5194/acp-10-341-2010, 2010.