Becky Alexander


The ICE age Chemistry And Proxies (ICECAP) model is a combination of (1) a global climate model (GISS ModelE), (2) and equilibrium global terrestrial vegetation model (BIOME4), (3) a paleo-fire model (LPJ-LMFire), and (4) a global chemical transport model (GEOS-Chem) that includes a stratospheric chemistry model (LinOz). The primary goal of this project is to investigate the variability in the oxidation capacity of the atmosphere on the preindustrial-industrial and glacial-interglacial time scales. The model calculates the oxygen isotopic composition of sulfate and nitrate, observations of which can be used to assess model performance.



  • Becky Alexander and Eric Sofen (UW)
  • Loretta Mickley , Lee Murray, and Amos Tai (Harvard)
  • Jed Kaplan (U. Geneva)


NSF AGS 0704169

Publications so far

  • Sofen, E.D., B. Alexander, E.J. Steig, M.H. Thiemens, S.A. Kunasek, H.M. Amos, A.J. Schauer, M.G. Hastings, J. Bautista, T.L. Jackson, L.E. Vogel, J.R. McConnell, D.R. Pasteris, and E.S. Saltzman, WAIS Divide ice core suggests sustained changes in the atmospheric formation pathways of sulfate and nitrate since the 19th century in the extratropical Southern Hemisphere, Atmos. Chem. Phys. Discuss., 13, 23089-23138, doi:10.5194/acpd-13-23089-2013 (2013).
  • Murray, L.T., L.J. Mickley, J.O. Kaplan, E.D. Sofen, M. Pfeiffer, and B. Alexander, Factors controlling variability in the oxidative capacity of the troposphere since the Last Glacial Maximum, Atmos. Chem. Phys. Discuss. 13, 24517-24603, doi:10.5194/acpd-13-24517-2013 (2013).
  • Tai, A.P.K., L.J. Mickley, C.L. Heald, and S. Wu, Effect of CO2 inhibition on biogenic isoprene emission: Implications for air quality under 2000-to-2050 changes in climate, vegetation, and land use, Geophys. Res. Lett., 40, 3479-3483, doi:10.1002/grl.50650.
  • Sofen, E.D., B. Alexander, and S.A. Kunasek, The impact of anthropogenic emissions on atmospheric sulfate production pathways, oxidants, and ice core Δ17O(SO42-), Atmos. Chem. Phys., 11, 3565-3578, doi:10.5194/acp-11-3565-2100 (2011).