Dr. Robert J. Yokelson
Adjunct Associate Professor of Chemistry
Email: bob.yokelson@umontana.edu
Phone: (406) 329-4812
Dr. Yokelson carried out his Ph.D. research with Dr. W. A. Chupka at Yale University studying excited states of O2 by multiphoton laser spectroscopy in tandem with molecular beam mass spectrometry. He carried out postdoctoral studies with A. R. Ravishankara at the National Oceanic and Atmospheric Administration Aeronomy Lab ( NOAA ) studying atmospheric photochemistry and kinetics using a variety of time-resolved absorption techniques.
Research Results / Publications / Links of Interest / Contact
Research Interests - Rationale and Overview (top)
Biomass burning is an important part of the natural ecology of forests throughout the world, a crucial component of the agricultural systems that feed much of the world's population, a cost-effective land-management tool, and a source of renewable energy used by about one-half of our planets inhabitants. Biomass burning is also a significant source of atmospheric trace gases and particles contributing 20-80% of the total emissions for many important chemical species. Uncertainty in the initial characteristics and subsequent transformations of these emissions is a major limiting factor in models of regional-global atmospheric chemistry, radiative transfer, and climate change. The complex mixture of reactive emissions from fires presents a very challenging measurement problem. To better characterize biomass-burning emissions, and their transformations, we have been developing new measurement systems that capitalize on the ability of Fourier transform infrared spectroscopy (FTIR) to measure a wide variety of reactive and stable compounds in real time. We have developed an open-path FTIR (OP-FTIR) system for ground-based and laboratory measurements and closed-cell FTIR systems for airborne measurements (AFTIR) and highly mobile ground-based measurements. Deployment of these instruments in the laboratory and in important fire environments around the globe is helping us better understand the impact of fires. Below is a chronological set of links leading to research summaries for each of our campaigns to date.
Research Resutls (top)
- 2006-7 Field Measurements in México
- 2004 Field Measurements in Brazil - The Tropical Forest and Fire Emissions Experiment (TROFFEE)
- 2003 Laboratory Instrument Intercomparison with NCAR
- 2001 Laboratory Instrument Intercomparison with Max Planck Institute and UC Irvine
- 2000 Field Measurements in Southern Africa (SAFARI 2000)
- 1999 Measurements of Residual Smoldering Combustion (RSC)
- 1997 Field Measurements in Alaska and North Carolina
Representative Publications (top)
Yokelson, R. J., Christian, T. J., Karl, T. G., and Guenther, A.: The tropical forest and fire emissions experiment: Laboratory fire measurements and synthesis of campaign data, Atmos. Chem. Phys. Discuss., 8, 4221-4266, 2008.
Christian, T. J., R. J. Yokelson, J. A. Carvalho, Jr., D. W. T. Griffith, E. C. Alvarado, J. C. Santos, T. G. S. Neto, C. A. G. Veras, and W. M. Hao, The tropical forest and fire emissions experiment: Trace gases emitted by smoldering logs and dung from deforestation and pasture fires in Brazil, J. Geophys. Res., 112, D18308, doi:10.1029/2006JD008147, 2007.
Yokelson, R. J., et al., Emissions from forest fires near Mexico, Atmos. Chem. Phys., 7, 6687-6718, 2007.
Yokelson, R. J., T. Karl, P. Artaxo, D. R. Blake, T. J. Christian, D. W. T. Griffith, A. Guenther, and W. M. Hao, The Tropical Forest and fire emissions experiment: overview and airborne fire emission factor measurements, Atmos. Chem. Phys., 7, 6903-6958, 2007.
Karl, T. G., T. J. Christian, R. J. Yokelson, P. Artaxo, W. M. Hao, and A. Guenther, The tropical forest and fire emissions experiment: method evaluation of volatile organic compound emissions measured by PTR-MS, FTIR, and GC from tropical biomass burning, Atmos. Chem. Phys., 7, 8755-8793, 2007.
Karl, T., A. Guenther, R. J. Yokelson, J. Greenberg, M. Potosnak, D. R. Blake, and P. Artaxo, The tropical forest and fire emissions experiment: Emission, chemistry, and transport of biogenic volatile organic compounds in the lower atmosphere over Amazonia, J. Geophys. Res., 112, D18302, doi:10.1029/2007JD008539, 2007.
Yokelson, R. J., T. Karl, T. J. Christian, P. Artaxo, J. A. Carvallo, Jr., E. C. Alvarado, J. Greenberg, D. R. Blake, and A. Guenther, Airborne and ground-based measurements of fire and biogenic emissions during the 2004 Amazonian dry season, iLEAPS Newsletter, 4, 30-32, 2007.
Mason, S.A., J. Trentmann, T. Winterrath, R.J. Yokelson, T.J. Christian, L.J. Carlson, T.R. Warner, L.C. Wolfe, and M.O. Andreae, Intercomparison of two box models of the chemical evolution in biomass-burning smoke plumes, J. Atmos. Chem., DOI 10.1007/s10874-006-9039-5, 2006.
Contact Details (top)
Robert J. Yokelson, Adjunct Associate Professor, (406) 329-4812 (
bob.yokelson@umontana.edu
)
Ted J. Christian, Assistant Research Professor, (406) 329-4878 (
ted.christian@umontana.edu
)
Department of Chemistry
University of Montana
Missoula, MT 59812
