Studentships are available in atmospheric science from October 2013 in the following areas:
Project 1: Formation processes and composition of organic aerosols studied in an atmospheric simulation chamber. Enquiries: Dr Markus Kalberer (markus.kalberer@atm.ch.cam.ac.uk)
The formation processes of particles in the atmosphere are still largely unknown and are one of the reasons why aerosol particles are a highly uncertain aspect of the Earth's climate system. In particular the role of organic compounds, from natural and anthropogenic sources, is not well understood. In this project a newly developed online ultra-high resolution mass spectrometry technique (extractive electrospray ionization) will be used to characterize the chemical composition of organic particles with high time resolution. The particle analysis will be complemented with state-of-the-art gas phase analyses using a proton-transfer-reaction mass spectrometer. Experiments will be performed using a large-scale atmospheric simulation ("smog") chamber. The simultaneous analysis of gas and particle components with unprecedented time resolution and sensitivity will allow to study in detail the fast gas/particle transition processes that lead to particle formation in the atmosphere. A range of atmospherically relevant model particle systems will be studied in the simulation chamber such as the formation of particle from terpenes and aromatic compounds, which are representative for biogenic and anthropogenic particle formation processes, respectively.
Project 2: Characterisation and quantification of oxidising aerosol particle components relevant for health-related aerosol effects. Enquiries: Dr Markus Kalberer (markus.kalberer@atm.ch.cam.ac.uk)
Atmospheric aerosol particles are among the most important health-relevant air pollution components. Clear correlations between exposure to increased levels of aerosols and severe health effects have been observed. Particle components and properties causing these health effects are not well understood, but oxidising particle components could play an important role, inducing oxidative stress in the lung and ultimately inflammation and disease. A novel instrument, which was recently built in our group, to quantify the oxidative potential of aerosol particles will be further developed. Using fluorescence spectroscopy this new instrument allows quantifying for the first time highly reactive and short-lived oxidizing particle components, which are potentially a better indication of health-relevant particle property than currently measured air pollution parameters. The oxidative potential of aerosol particle from various sources such as secondary organic particles formed in the atmosphere and from primary sources such as fossil fuel or biomass combustion will be investigated. It is expected that the newly developed instrument will also be deployed in collaborative projects with lung biology or epidemiology groups.
Project 3: Detailed investigation of the structure of the tropopause region. Enquiries: Prof. John Pyle (john.pyle@atm.ch.cam.ac.uk)
The tropopause in both the tropics and extratropics is a crucial region for chemical and climate processes. Processes there control the transport of chemical species between troposphere and stratosphere. Composition around the cold tropopause exerts an important influence on surface climate. Two opportunities make this a region ripe for detailed study. First, we have developed a new chemistry/climate model which now includes both the chemistry of the troposphere and the stratosphere, so that the crucial boundary between these two regions, the tropopause, is well covered. Secondly, we are involved in a NERC project which will exploit NASA's high-flying unmanned Global Hawk aircraft to make composition measurements in this region in early 2014, measurements which will be unprecedented in their spatial and temporal coverage. The student will run the numerical model to study transport, and chemical processing, as air moves from the tropical surface into the low stratosphere. The model will be evaluated against data. We can run the model at high spatial resolution, using observed meteorology, specifically to investigate interesting features shown in the data. The combination of new data and our model offers a potential revolution in our understanding of this area.
Project 4: Methane and chemistry-climate studies. Enquiries: Prof. John Pyle (john.pyle@atm.ch.cam.ac.uk)
Methane is a key greenhouse gas. It also plays an important role in atmospheric chemistry, both in the troposphere and stratosphere. In an on-going NERC consortium project, we are developing new global emissions for methane, including the temperature dependence of the emissions. The student will implement these into our global chemistry/climate model. The model will be used: (i) to explore present day methane distributions - how well do our new emissions describe the methane distribution; are there areas of discrepancy and, if so, can we suggest physical explanations; (ii) to consider the impact on the coupled chemistry/climate of future emissions of methane. In particular, the student will explore the feedbacks between (i) methane changes and climate; (ii) methane changes and changes in tropospheric and stratospheric ozone; (iii) the ozone changes and climate.
Project 5: Ultralight sensor technology for sensing urban air quality, health impacts and greenhouse gases. Enquiries: Prof Rod Jones (rlj1001@cam.ac.uk)
Low cost lightweight gas and aerosol sensors are now becoming available for monitoring atmospheric composition and structure. Such devices are now becoming used in a number of applications in the urban boundary layer to the upper atmosphere, and from photochemically active gases such as O3 and NOx to gases important in the radiative budget of the atmosphere and thus to climate change such as H2O and CO2 and CH4. These sensors are now being integrated into networks, integrated with GPS for determining location (for mobile sensors) and GPRS for direct communication of measurements to central computers for real time data analysis and display. Specific projects include studies of urban photochemistry on the small-scale and its implication for composition on regional scales and upwards; personal exposure and health impacts; greenhouse gas monitoring for budget and source attribution. As part of the project the student would be able to participate in and develop a range of UK and European collaborations.
Project 6: Field observations of composition and structure using ultra sensitive spectroscopic methods. Enquiries: Prof Rod Jones (rlj1001@cam.ac.uk)
Cavity ringdown spectroscopy and its variants are ultra-sensitive spectroscopic techniques which can be used for measurements of a range of chemical species down to ppt levels. This project involves the use and minor adaptation of an existing three channel broadband cavity enhanced absorption spectrometer (BBCEAS) instrument, although there is the possibility of the development of a new ultra lightweight instrument use in unmanned airborne vehicles (UAVs). The groups of chemical species studies impact on local and regional ozone concentrations and thus the oxidising capacity of the troposphere. For the project, the existing BBCEAS instrument would be used for ground based studies of nitrogen oxide species (for example NO3, N2O5, HONO) to be based at the Weybourne Atmospheric Observatory and would then be adapted for airborne studies of halogen species (I2, OIO, IO) as part of the NERC CAST project. Ground-based studies would take place at UK sites while for the CAST project, the instrument would be mounted on the NERC FAAM BAE146 atmospheric research aircraft as part of an international study to take place in the west pacific region in 2014. As part of the project the student would be able to participate in and develop a range of UK and international collaborations.
Applicants should have (or expect to obtain) at least the equivalent of a II.1 honours degree (and preferably a Masters) in chemistry, physics, environmental science, or a related area. All projects are funded by NERC, and will cover tuition fees and an annual maintenance grant for EU nationals who satisfy the eligibility requirements of the UK Research Councils. The studentships are not available to non-EU nationals.
Applications should include a CV, contact details for two professional referees, and should be sent to Alice Wood, Department of Chemistry, Lensfield Road, Cambridge CB2 1EW (email: aw534@cam.ac.uk), indicating which project(s) you are interested in.
