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Paul Griffiths BA DPhil

PhD student

Impact of aerosol particles on the precipitation efficiency of convective clouds.

Biography

Career

  • 1998-2000: Research Fellow, Vrije Universiteit, Amsterdam.
  • 2000-2008: Research Assistant, Chemistry Department, Cambridge University.
  • 2006-2007: Visiting Scientist, ICG-II, Forschungszentrum Juelich.
  • 2006-Present: Fellow in Chemistry, Girton College, Cambridge.

Qualifications

  • 1990-1994: B.A.(Hons) Chemistry, Oxford University.
  • 1994-1998: D.Phil. Surface Science Photochemistry and Reaction Dynamics, Oxford University.

Research

My Ph.D. research involves modelling the effects of aerosol on clouds and precipitation. Clouds are an important component of the Earth's climate system: they reflect incoming solar radiation, cooling the Earth; their formation releases latent heat and drives atmospheric circulation; during precipitation, evaporated moisture is returned to the Earth's surface and the hydrological cycle is maintained. Clouds form by condensation of water vapour onto atmospheric aerosol, and the effect of the underlying aerosol on cloud properties has been and remains an active area of climate research.

The goal of my project is to simulate the formation of clouds and precipitation in convectively driven clouds within the framework of an existing cloud-resolving atmospheric model, ATHAM, developed by Graf, Herzog and co-workers. To do this, a comprehensive aerosol-cloud module will be developed that describes as far as possible the relevant dynamical and microphysical processes from first principles. The performance of the module will be tested using both warm and mixed-phase clouds, using ATHAM to simulate the properties of shallow and deep convective systems. Of particular interest are convective events over the Amazon region, where there is evidence of a strong effect of aerosol on precipitation. Lately, I've been working on developing a two-moment scheme for warm cloud microphysics which I've been testing in single-column and 2D models.

Publications

Selected publications

  • C. D. Kolb, R. A. Cox, C. O'Dowd, P. T. Griffiths et al., An overview of current issues in the uptake of atmospheric trace gases by clouds and aerosols. Atmospheric Chemistry and Physics, 10, p.10561-10605, 2010.
  • F.D. Pope, L. Harper, B. J. Dennis-Smither, P. T. Griffiths, S. L. Clegg and R. A. Cox, Studies of single aerosol particles containing of malonic acid, glutaric acid, and their mixtures with sodium chloride. I. Hygroscopic growth and II. Vapour pressures of the acids. J. Phys. Chem, 2010.
  • P.T. Griffiths and R.A. Cox. Temperature dependence of reactive uptake of N2O5 by ammonium sulfate aerosol. Atmospheric Science Letters, DOI: 10.1002/asl.225, 2009.
  • P.T. Griffiths, C.L. Badger, R.A. Cox, M. Folkers, H. Henk and T.F. Mentel. Reactive uptake of N2O5 by dicaboxylic acid aerosol. J. Phys. Chem, 113, p.5082, 2009.
  • Mentel, T.F., J. Wildt, A. Kiendler-Scharr, E. Kleist, R. Tillmann, M. Dal Maso, R. Fisseha, Th. Hohaus, H. Spahn, R. Uerlings, R. Wegener, P. T. Griffiths, E. Dinar, Y. Rudich, and A. Wahner.
 Photochemical production of aerosols from real plant emissions. Atmospheric Chemistry and Physics, 9, p.4387, 2009.
  • Roberts, T.J., C.F. Braban, R.S. Martin, C. Oppenheimer, J.W. Adams, R.A. Cox, R.L. Jones, and P.T. Griffiths. Formation of BrO and ClOx in volcanic plumes and chemical impacts on O3, Chemical Geology, in press. , 2009.
  • R.J. Gustafsson, P.T. Griffiths, R. A. Cox, R. M. Lambert, Reduction of NO2 to nitrous acid on illuminated titanium dioxide aerosol surfaces: implications for photocatalysis and atmospheric chemistry, Chemical Communications, 37 (2006) p. 3936.
  • C. L. Badger, P. T. Griffiths and R. A. Cox, Reactive uptake of N2O5 by aerosol particles containing humic acid aerosol and mixtures of humic acid and ammonium sulfate. Journal of Physical Chemistry A, DOI 10.1021/jp0562678.
  • M. J. L. de Lange, M. Drabbels, P. T. Griffiths, J. Bulthuis, and S. Stolte, Steric asymmetry in state-resolved NO-Ar collisions Chemical Physics Letters 313 (1999) p. 491.

Teaching

  • 2006-2008: Teaching Fellow, Chemistry Dept.
  • 2008-2009: Affiliate Lecturer, Chemistry Dept.

External activities

  • Member, AGU, RSC, RMetSoc