School of Earth and Environment
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Ryan Hossaini Ryan Hossaini

Postgraduate Student/Temporary Researcher

Telephone number: +44(0) 113 34 35612
Email address: chm3rh@leeds.ac.uk
Room: 10.126

Link to personal page

Biography

I am a final year NERC funded PhD student within the Institute for Climate and Atmospheric Science (ICAS). I work in the TOMCAT/SLIMCAT global modelling research group.

Qualifications

  • MRes Physics of the Earth and Atmosphere, University of Leeds
  • BSc Environmental Chemistry, University of Leeds

Research Interests

  • Halogen chemistry in the global troposphere/stratosphere
  • Composition of the tropical tropopause layer (TTL)
  • Global modelling (CTMs and CCMs)
  • Chemistry-climate interactions and future change

Project details

Project title

Global chemistry-climate modeling: Impact of very short-lived species (VSLS) on stratospheric ozone

Supervisors

Professor Martyn Chipperfield

Funding

NERC

Start date

October 08

Project outline

Halogen-containing very short-lived species (VSLS) are thought to provide the stratosphere with an additional supply of inorganic bromine (Bry), chlorine (Cly) and perhaps iodine (Iy). Emissions of VSL source gases (SGs, e.g. CHBr3, CH2Br2) are predominately of natural oceanic origin with a sizeable fraction occurring in the tropics. Rapid vertical transport in deep convective systems allows these species to overcome their short local lifetimes and reach the tropical tropopause layer (TTL). From here, vertical ascent into the stratospheric over world or isentropic quasi-horizontal mixing with the extra-tropics is possible. VSLS are currently neglected in most chemical transport models (CTMs) and also chemistry-climate models (CCMs). This omission is addressed in the present research in order to quantify the impact of VSLS on the stratospheric halogen budget and also the resultant effect on stratospheric composition (e.g. depletion of O3) under present day and (potential) future climates.

Publications

Hossaini, R., Chipperfield, M. P., Feng, W., Breider, T. J., Atlas, E., Montzka, S. A., Miller, B. R., Moore, F., and Elkins, J.: The contribution of natural and anthropogenic very short-lived species to stratospheric bromine,  Atmos. Chem. Phys., 12, 371-380, doi:10.5194/acp-12-371-2012, 2012.

Aschmann, J., Sinnhuber, B.-M., Chipperfield, M. P., and Hossaini, R.: Impact of deep convection and dehydration on bromine loading in the upper troposphere and lower stratosphere, Atmos. Chem. Phys., 11, 2671-2687, doi:10.5194/acp-11-2671-2011, 2011.

Hossaini, R., Chipperfield, M. P., Monge-Sanz, B. M., Richards, N. A. D., Atlas, E., and Blake, D. R.: Bromoform and dibromomethane in the tropics: a 3-D model study of chemistry and transport, Atmos. Chem. Phys., 10, 719-735, doi:10.5194/acp-10-719-2010, 2010