Professor Dave Waltham (RHUL Earth Sciences)
The atmosphere of the Earth is an oxidizing medium and effectively acts as a low temperature, dilute fuel, combustion system, oxidizing complex compounds and returning them to the surface of the Earth via cloud water and dry deposition. The chemical composition of particulate matter affects climate directly, by scattering and absorbing solar radiation, and indirectly, owing to its ability to act as cloud condensation nuclei, leading to a change in cloud formation rainfall patterns. Cloud processing of atmospheric particulate matter changes the optical properties of clouds.
Atmospheric mineral particulate matter contains organic films that affect the reactivity of the particles and their potential to act as cloud condensation nuclei. You will study the optical properties and kinetics of atmospheric oxidants reacting with organic films on mineral aerosol. The kinetics will give an atmospheric lifetime and the optical properties will enable calculation of the change in climatic radiative forcing. If the lifetime is less than ten days and more than 1 minute then it is climatically important.
You will be based at the enviable facilities of the Rutherford-Appleton laboratory (Oxfordshire) and undertake experiments at the central laser facility with supervisors currently working with RHUL students. You will extract organic material from atmospheric aerosol, place it on spheric mineral particles and subject it to atmospheric oxidation whilst held in a laser trap. Neutron reflection studies will determine the morphology and thickness of the organic material, allowing an assessment of its atmospheric lifetime. Laser tweezer studies will determine the refractive index of the material during oxidation allowing the estimation of a change in radiative forcing due to atmospheric oxidation.
You will train in advanced techniques to study a new interface between mineral matter and water. The Rutherford-Appleton Laboratory will allow you to interact with many world-leading scientists. You will be trained in laser spectroscopy, neutron reflection, chemical extraction, atmospheric sampling and atmospheric modelling achieving a PhD with modelling, field and laboratory components.
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Candidates with degrees in Chemistry, Physics, Engineering or Earth Science are encouraged to apply.