Injection height and long-range transport of biomass burning emissions: A comparison of satellite observations and numerical models

The injection height of biomass burning emissions plays a critical role in determining their long-range transport. Generally speaking, the higher such emissions are directly injected into the troposphere the more likely they may be transported far from the emission sources. In the most extreme cases, in a matter of minutes, pyrocumulonimbus (pyroCb) plumes can lift biomass burning emissions to the tropopause where jet streams blow the material around the globe in less than two weeks. Although some material emitted into the boundary layer is likely to become mixed and removed through chemical and precipitation processes, some of it can be lifted into the free troposphere by deep convection or synoptic scale uplift in “warm conveyor belts.” As recently as five years ago, most numerical transport models assumed all biomass burning emissions were emitted at the surface. Now, most models assume some vertical profile of emission injection, while some use detailed plume-rise models on a case-by-case basis. Nevertheless, the amount of biomass burning material directly injected above the boundary layer remains an issue of much debate. Recent NASA and EUMETSAT satellites offer unparalleled capabilities for daily near global remote sensing of aerosols and carbon monoxide (CO). Onboard the Aqua satellite, the Atmospheric InfraRed Sounder (AIRS) provides CO maps covering 70% of the Earth every day. Near global total column aerosol information is retrieved from observations of the MODerate resolution Imaging Spectroradiometer (MODIS) onboard Aqua and Terra. Information on the vertical distribution and shape of aerosols comes from the CALIOP lidar onboard the Calipso satellite in the middle of the A-Train. The EUMETSAT's Metop-A satellite carries the Infrared Atmospheric Sounding Interferometer (IASI) with similar CO capabilities to AIRS. Utilizing a combination of satellite observations of carbon monoxide and aerosols with trajectory and numerical simulations from the GOddard Chemistry Aerosol Radiative Transport (GOCART) model, we will elucidate the plume injection heights for a number of large biomass burning events including Southeast Asian and Indonesian fires in 2006 and pyroCb's in 2006 and 2009.