A modeling study of atmospheric transport and photochemistry in the mixed layer during anticyclonic episodes in Europe. Part I: meteorology and air trajectories.

Abstract

A climatological study was carried out of the occurrence and properties of a large number of dry and sunny spells in recent summers (1976-1983). The frequency of the spells, which are very favourable for atmospheric photochemical activity were found to be significantly higher in the investigated period than in previous years. A detailed examination of twenty five episodes were carried out. During the episodes, 72 h back trajectories were computed and information provided on temperature, humidity, cloud cover and inversion height. The trajectories, determined at different altitudes for five receptor locations in Europe, show a predominance for advection from eastern and western Europe. For the two more northerly European locations, the air trajectories also pass over less densely populated or maritime regions. Ozone concentrations, recorded at a station in The Netherlands, were examined in relation to the direction of the arriving air mass. (from authors' abstract)