Ozone deposition in Hurdal 2004-2006: Data analysis and testing of parameterisations.

Abstract

Estimates of diurnal and seasonal variation of ozone flux parameters to a temperate coniferous forest over 3 years in Southern Norway are presented. The turbulent transfer coefficient, the ozone flux and the deposition velocity are calculated by the gradient method using alternative profile parameterisations. Even if annual and diurnal profiles of directly measured meteorological and sonic parameters show well known patterns, the corresponding resulting curves for the ozone flux and the deposition velocity are highly variable with unexpected elevated values during night, especially in fall. Performances with alternative profile parameterisations and a comparison between the turbulent and a sonic transfer coefficient correspond very well, particularly in the timing of the profiles. Improved results are expected if longer time series are considered in the calculations of the daily and monthly averages. Additionally the elevation of the upper measurement height is thought to ameliorate the measurements and data base.