A PARAMETERIZATION OF THE NOCTURNAL OZONE REDUCTION IN THE RESIDUAL LAYER BY VERTICAL DOWNWARD MIXING DURING SUMMER SMOG SITUATIONS USING SODAR DATA

The reduction of ozone in the nocturnal residual layer by vertical mix ing to the surface was investigated for several summer smog episodes o n the Swiss plateau in the years 1990 and 1998. Using a limited data s et of SODAR measurements and surface ozone concentrations, a parameter ization of the ozone depletion in the nocturnal residual layer due to vertical mixing to the ground is proposed. This model is not intended to be physically complete but is rather simple with limited input info rmation required. The nocturnal ozone reduction within the whole plane tary boundary layer (nocturnal boundary layer plus residual layer) ove r the complex terrain of the Swiss plateau for the days investigated i s between 20 and 50%.