The impact of dynamic processes on chemistry in atmospheric boundary layers over tropical and boreal forest

Abstract

Improving our knowledge of the atmospheric processes that drive climate and air quality is very relevant for society. The application of this knowledge enables us to predict and mitigate the effects of human induced perturbations to our environment. Key factors in the current and future climate evolution are related to the emissions and atmospheric presence of carbon dioxide (CO2) and hydrocarbons. The latter group of chemical species, on which special emphasis is placed in this dissertation, control the capacity of the atmosphere to oxidize other reactants. In this way, hydrocarbons influence the residence time of many compounds in the atmosphere. It should be realized that the influence of mixing and transport cannot be ignored in studies of atmospheric chemistry. In this thesis, numerical models are used to investigate the influence of air flows on atmospheric chemistry in the lowest atmospheric layer (the so-called planetary boundary layer). Supported by observational data, we systematically study how the concentrations of chemical species like ozone depend on the time evolution of the planetary boundary-layer height. This analysis is extended by investigating how non-uniform distributions within the planetary boundary layer and transport by fair weather clouds influence the temporal evolution of chemical compounds. </p