The upper atmosphere physics group at Maynooth is concerned with the physics of the atmosphere altitudes between 80 and 250 km, with particular emphasis on the region known as the mesopause (80-100 km). The mesopause is the coldest layer in the Earth's atmosphere and is the region about which the least is known due to its inherent complexity and because of difficulties in the past in making measurements at this altitude. This layer has become the focus of much research in recent years because it is believed that the impact of human activity will have a profound impact there. A number of dedicated satellites, TIMED and AURA (USA) and ACE (Canada), have begun to address the dearth of measurements in this region, but considerable work remains before the complex interplay of chemistry, dynamics and radiation balance is understood satisfactorily.
Minor constituents in the atmosphere can exert a much greater influence than might be expected from their prevalence alone, a point illustrated only too well by the twin atmospheric problems of global warming (increased concentrations of CO2 and CH4) and ozone depletion. One of the most interesting minor constituents in the atmosphere is the OH radical partly because it is such a reactive species. The chemical reaction that produces OH (H + O3 --> OH* + O2) plays a crucial role in the mesosphere, where it represents a significant fraction of the energy input there. Studies at Maynooth are conducted on this emission through the use of ground-based spectroscopic measurements and satellite data. The main aim of the work is to develop an improved understanding of the diurnal and seasonal variations of the OH* emission as a function of latitude and local time.
Publications can be found at http://physics.nuim.ie/staff/PublicationsFJM.shtml
For further information contact Dr. Frank Mulligan at 01-7083746.