The Problem: Halogenated compounds have a major impact on the Earth's climate through stratospheric ozone depletion and the greenhouse effect.  Many of the ozone depleting gases are banned through the Montreal Protocol, although some are still being emitted from exempted uses, existing equipment, natural processes and unreported activity or new technologies.  There are also several fluorinated compounds which are very potent greenhouse gases (GHG).

At UEA we have been making measurements, for many years, of halogenated compounds in air samples collected around the world from ground sites, balloons, aircraft, and snow, and through 2-D global modelling we have assessed their atmospheric emissions.  This work has fed into policy via UNEP/WMO assessments and the Montreal Protocol.

This work is ongoing as we discover new compounds and update the trends of others.  For example, we recently published the first trends, and derived emissions, of 4 perfluorocarbons (Laube et al, 2012), which have global warming potentials (GWPs) of around 9000 (i.e. 9000 times more potent than CO2).  In 2000 we discovered another potent GHG, SF5CF3 (GWP = 22000), which was rapidly increasing in the atmosphere.   More recently, we showed from new observations and modelling that the emissions of this gas have now halted (Sturges  et al, 2012).

Whilst determining global emissions for these gases is very important it is also extremely interesting and of value to policy makers to determine regional emissions.  This requires a regional analysis.

The Research: The student will use the 2-D model to investigate new GHG and to re-evaluate others as their trends are updated. Furthermore the student will develop the use of a 3-D regional model to simulate the emissions and transport of halogenated gases on regional scales to determine the impact of different source types and regions.  These simulations will be constrained by data from measurement programmes in the UK and S. E. Asia. The latter is being further developed through collaboration with the University of Malaya and the establishment of a new monitoring station in Malaysia that receives air from China where emissions of GHG are rapidly increasing.

Requirements, Training, Opportunities: This project is suitable for a student with a strong interest in atmospheric science and numerical modelling.  They should have a degree in atmospheric science, meteorology, environmental science, chemistry or physics (graded 2:1 or above). The student will work with scientists at UEA and the National Centre for Atmospheric Science involved in the halocarbon measurement programmes and may have the opportunity to engage with our Malaysian collaborators.  The student will receive training in the use of models, handling and interpreting data. If appropriate, the student may attend master level lectures in atmospheric science to supplement their existing knowledge.
 

Laube, J.C., C. Hogan, M.J. Newland, F.S. Mani, P.J. Fraser, C.A.M. Brenninkmeijer,

P.Martinerie, D.E. Oram, T. Röckmann, J. Schwander, E. Witrant, G.P. Mills, C.E. Reeves and W.T. Sturges, Distributions, long term trends and 1 emissions of four perfluorocarbons in remote parts of the atmosphere and firn air, Atmos. Chem. Phys., 12, 4081-4090, doi:10.5194/acp-12-4081-2012, 2012.

Sturges, W.T., D. E. Oram, J. C. Laube, C. E. Reeves, M. J. Newland, C. Hogan, P. Martinerie, E. Witrant, C. A. M. Brenninkmeijer, T. J. Schuck and P. J. Fraser, Emissions halted of the potent greenhouse gas SF5CF3, Atmos. Chem. Phys., 12, 3653-3658, doi:10.5194/acp-12-3653-2012, 2012.

Laube, J.C., P. Martinerie, E. Witrant, T. Blunier, J. Schwander, C. A. M. Brenninkmeijer, T. J. Schuck, M. Bolder, T. Röckmann, C. van der Veen, H. Bönisch, A. Engel, G. P. Mills, M. J. Newland, D. E. Oram, C. E. Reeves, and W. T. Sturges, Accelerating growth of HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) in the atmosphere, Atmos. Chem. Phys., 10, 5903-5910, 2010.

Reeves, C.E., W.T. Sturges, G.A. Sturrock, K. Preston, D.E. Oram, J. Schwander, R. Mulvaney, J.-M. Barnola, and J. Chappellez, Trends of halon gases in polar firn air: implications for their emission distributions, Atmos. Chem. and Phys, Page(s) 2055-2064. SRef-ID: 1680-7324/acp/2005-5-2055, 2005.

Reeves, C.E., Atmospheric budget implications of the temporal and spatial trends in methyl bromide concentration, J. Geophys. Res., 108 (D11), 10.1029/2002JD002943, 11 June 2003.