A suggestion of a simple transfer function for the use of ozone monitoring data in dose-response relationships obtained using open-top chambers

摘要

A simple relationship for transforming ozone monitoring data from different measurement heights to the level relevant to response functions obtained using open-top chambers is suggested. The transfer function was tested using measurements at different heights above the ground (1.1, 2 and 10 m) over a field crop of oat. Only daytime conditions with ozone concentrations above 30 ppb at 10 m height were considered. The agreement between the measured and the calculated ozone concentration at plant height was good, with the exception of situations with very low wind speeds. Thus, the transfer function offers an opportunity to make corrections for the vertical ozone concentration gradient in estimations of yield loss due to ozone. Required input data are monitoring height, stand height of the crop and wind speed. The canopy resistance to ozone uptake, r(c), for cereals was set to 75 s m(-1) based on published data. Using the present data set, a typical daytime value of r(c) was found to be 80 s m(-1). Considering only situations with Photosynthetically Active Radiation (PAR) >700 mole m(-2) s(-1), a typical value was around 60 s m(-1). References: 17