Through her graduate and post-graduate studies Sarah has been very actively involved in research on atmospheric aerosols. Aerosols are small particles suspended in the atmosphere that interact with sunlight, thereby reducing the amount of sunlight that reaches the surface of the earth and, when the particles are dark (i.e. gray, brown or black), heating the atmosphere. Sarah’s research has focused on assessing the optical properties of aerosols from both natural and anthropogenic sources. For seven years (2003-2010) she was the Executive Officer of the International Global Atmospheric Chemistry Project where she combined her research efforts with organizing multi-national science initiatives, workshops and conferences. She left this position to return to full-time research at JISAO. She currently studies the impact of a certain type of aerosols, “black carbon” (more commonly known as soot) on climate, in particular when they affect snow reflectivity. Model studies indicate that soot from biomass burning, biofuel burning, transportation and industrial activities may be sufficiently darkening snow in the Arctic to be contributing to melting and may be responsible for a significant fraction of northern hemisphere warming.
Sarah and her colleagues in the University of Washington Dept. of Atmospheric Sciences recently completed a pan-Arctic campaign to quantify the amount of soot and dust/soil in snow from samples across the Arctic. Model studies indicate that soot in snow is contributing to Arctic warming, and this data set can be used to test these models. She has also collaborated with colleagues in China to made similar measurements across northern China and is current co-leading an expedition (winters 2013 & 2014) measuring soot in snow in the North American Great Plains region. Her interests have recently expanded from measurements to global climate modeling. She is collaborating with colleagues at the Univ. of Washington and Harvard University on a project looking at what factors may be driving Arctic sensitivity to black carbon. She is second coordinating lead author on a multi-national paper on “Bounding the role of black carbon in climate: A scientific assessment”. This effort was initiated when she was IGAC Exec. Officer, and her contributions were both organizational and scientific, leveraging her expertise in aerosols and snow measurements and her interest in climate modeling.
Current Research Projects
- Black carbon (“soot”) in snow on the N. American Great Plains and its effect on climate (with Profs. Steve Warren, Dean Hegg & Qiang Fu, UW Dept of Atmospheric Science)
- Modeling the influence of black carbon on Arctic climate (with Prof. Cecelia Bitz, UW Dept of Atmospheric Science)
- Participation in “Bounding the role of black carbon in climate: A scientific assessment”
Bond, T. C., S. J. Doherty, D. W. Fahey, P. M. Forster, et al., Bounding the Role of Black Carbon in Climate: A scientific assessment, J. Geophys. Res., 118 (11),5380-5552, doi:10.1002/jgrd.50171, 2013.
Doherty, S. J., T. C. Grenfell, S. Forsström, D. L. Hegg, S. G. Warren and R. Brandt, Observed vertical redistribution of black carbon and other light-absorbing particles in melting snow, J. Geophys. Res.,118(11), 5553-5569, doi:10.1002/jgrd.50235, 2013.
Wang, X., S. J. Doherty and J. Huang, Black carbon and other light-absorbing impurities in snow across Northern China, J. Geophys. Res., 118 (3), 1471-1492, doi:10.1029/2012JD018291, 2013.
Doherty, S. J., S. G. Warren, T. C. Grenfell, A. D. Clarke, R. Brandt, Light-absorbing impurities in Arctic snow, Atmos. Chem. Phys., 10, 11647-11680, doi:10.5294/acp-10-11647-2010, 2010.
Doherty, S. J., S. Bojinski, A. Henderson-Sellers, K. Noone, D. Goodrich, N. L. Bindoff, J. A. Church, K. A. Hibbard, T. R. Karl, L. Kajfez-Bogataj, A. H. Lynch, D. E. Parker, I. C. Prentice, V. Ramaswamy, R. W. Saunders, A. J. Simmons, M. Stafford Smith, K. Steffen, T. F. Stocker, P. W. Thorne, K. E. Trenberth, M. M. Verstraete, F. W. Zwiers, Lessons learned from IPCC AR4: Future scientific developments needed to understand, predict and respond to climate change, Bull. Amer. Met. Soc., 90(4), 497–513, 2009.
Doherty, S.J., P. Quinn, A. Jefferson, C. Carrico, T. L. Anderson, D. Hegg, A comparison and summary of aerosol optical properties as observed in-situ from aircraft, ship and land during ACE-Asia, J. Geophys. Res., 110, D04201, doi:10.1029/2004JD004964, 2005.