Problems to be solved
Ozone in the upper troposphere is an important greenhouse gas that is formed mainly by photolytic degradation of NOx. Between 40 and 50° N, some 40 % of upper tropospheric NOx over Europe is a result of transport from the polluted boundary layer, with aircraft emissions contributing a further 30 %. This program of research will allow us to estimate the influence of ubiquitous cirrus ice particles on upper-tropospheric oxidant cycles, and ozone concentrations. The resulting advancement in understanding of the photochemistry of this sensitive part of the atmosphere will enable improved assessment and control of ground and aircraft emissions that impact on upper-tropospheric ozone concentrations and thus the atmospheric radiation budget. The objectives of this proposal are consistent with contents of the Kyoto protocol and the Long-Range Transboundary Air Pollution Convention, which aim to better control the chemical species that have an impact on air quality and climate. It also has direct bearing on the policies of the Framework Convention on Climate Change (IPCC) and the International Civil Aviation Organisation (ICAO) which is responsible for the implementation of standards to regulate international air traffic.
Scientific Objectives and approach
This is a proposal of laboratory based research designed to enhance our understanding of the factors that influence the seasonal and latitudinal variability of ozone in the upper troposphere, and in particular the extent to which the natural chemistry of the upper troposphere is being impacted by growing atmospheric pollution. This proposal focuses on the role of cirrus ice in modifying the chemical composition of the upper troposphere, and its response to pollutant inputs. The chosen approach is to combine a number of different and complementary techniques to examine various aspects of the heterogeneous reactivity of ice. The laboratory experiments will employ both gas-phase analysis, and surface sensitive methods to examine aspects of ice reactivity towards members of the NOy family, oxidised organic species, halogen containing compounds and members of the HOy family and ozone.
CUT-ICE is a laboratory based proposal, and its major deliverable is a compiled and assessed data base of kinetic and mechanistic information that describes the interaction of atmospheric trace gases with ice surfaces. Due to present lack of suitable laboratory data, models cannot properly treat trace-gas / ice interactions. The implementation of the laboratory data from CUT-ICE will result in a significant advancement in the accuracy and thus the predictive capabilities of these models, enabling greatly improved assessment of e.g. the role of both aircraft and ground based emissions in modifying the ozone concentrations of the upper troposphere, and its influence on climate.
Funding SchemeCSC - Cost-sharing contracts
YO1 5DD York
CB2 1EW Cambridge