Jennifer A. Logan
Senior Research Fellow
School of Engineering and Applied Sciences
Harvard University

gomeFIRES: EMISSIONS, CHEMISTRY, INJECTION HEIGHTS, AND ATMOSPHERIC EFFECTS

BACKGROUND:

Forest fires in North America and Siberia have been increasing in frequency and size over the past decades. Emissions in high fire years such as 1998, 2002, and 2003 provide a major perturbation to the atmospheric composition of the northern hemisphere. The plumes can be injected at high altitudes due to the buoyancy associated with the fires, and this has important consequence for the persistence of these plumes and their atmospheric effects. We used satellite observations of fire locations from the MODIS instrument, carbon monoxide (CO) from the MOPITT satellite instrument, and aerosol stereoscopic data from the MISR satellite instrument to place constraints on fire emissions and injection heights.  We also investigated the effects of the fires on ozone and aerosols. We used detailed aircraft measurements from ARCTAS-B as well as satellite measurements from TES to examine the effects of emissions from boreal fires on atmosheric composition.

OBJECTIVES:

  • Obtain better estimates of emission rates and injection heights from extra-tropical forest fires
  • Use these data to evaluate models of fire plume heights
  • Assess the implications of injection above the boundary layer for trace gases
  • Assess the effects of boreal fires on air quality

APPROACH:

  • Construct high-resolution emission inventories for forest fires using information from satellite fire counts, local fire reports, and vegetation maps;
  • Conduct model analyses of fire emissions and their injection altitudes using CO observed from space, surface sites and aircraft;
  • Determine the NOy composition of emissions from boreal fires in fresh plumes, and consequences for tropospheric ozone;
  • Use stereoscopic observations of aerosols from MISR to analyze and constrain injection heights.

FINDINGS:

  • About 10% of the plumes from North America fires are above the boundary layer at the time of the MISR overpass (11:00-14:00 LT), while the remainder are in the boundary layer.
  • Plume heights are correlated with MODIS fire radiative power.
  • A plume height model currently used in several global and regional models does not simulate the MISR plume heights well, and does not identify the correctly the plumes that are above the boundary layer.
  • Emissions of NOx in ARCTAS-B fires were much lower than previously observed in boral fires, and there was rapid conversion to PAN
  • There was not much ozone formation for the ARCTAS-B fires.
  • Our bottom-up estimate of emissions from the North American boreal fires in 2004 is 30 Tg CO, of which 11 Tg is from peat
  • About half the emissions from the Siberian fires in 1998 appear to be injected above the boundary layer
  • The ozone enhancement from boreal fires is much larger when emissions are injected above the boundary layer

PEOPLE: Matthew Alvarado (now at AER), Maria Val Martin (now as Colorado State University), Fok-Yan Leung (now at Washinton State Univ.), Rose Yevich (now retired), Solene Turquety (now at Service d'Aeronomie, Paris), Jennifer Logan

COLLABORATORS:  David Diner and David Nelson (JPL) and Ralph Kahn (Nasa/Goddard)

REFERENCES:

  • Val Martin, M., R. A. Kahn, J. A. Logan, R. Paugam, M. Wooster, and C. Ichoku, Space-based observational constraints for 1-D plume rise models, J. Geophys. Res. 117, D22204, doi:10.1029/2012JD018370, 2012. [pdf]
  • Val Martin, M., J. A. Logan, R. Kahn, F.-Y. Leung, D. Nelson, and D. Diner, Smoke injection heights from fires in North America: Analysis of five years of satellite observations, Atmos. Chem. Phys., 10, 1491-1510, 2010. [PDF]
  • Alvarado, M.J., J. A. Logan, J. Mao, et al., Nitrogen oxides and PAN in plumes from boreal fires during ARCTAS-B and their impact on ozone: An integrated analysis of aircraft and satellite observations, Atmos. Chem. Phys., 10, 9739-9760, 2010. [PDF]
  • Kahn, R. A., Y. Chen, D. L. Nelson, F.-Y. Leung, Q. Li, D. J. Diner, and J. A. Logan, Wildfire smoke injection heights; two perspectives from space, Geophys. Res. Lett, 35, L04809, doi: 10.1029/2007GL032165, 2008.
  • Leung, F.-Y., J. A. Logan, R. Park, E. Hyer, E. Kasischke, D. Streets, and L. Yuganov (2007), Impacts of biomass burning in the boreal forests on tropospheric chemistry and the sensitivity of model results to injection height, J. Geophys. Res., D10313. [PDF]
  • Turquety, S., J. A. Logan, D. J. Jacob, R. C. Hudman, F. Y. Leung, C. L. Heald, R. M. Yantosca, S. Wu, L. K. Emmons, D. P. Edwards, and G. W. Sachse (2007), Inventory of boreal fire emissions for North America: importance of peat burning and pyro-convective injection, J. Geophys. Res., D12S03. [PDF]

SUPPORT: NSF, EPA, NASA