The Effect of Aging on an Empirical Relationship of Aerosol Index and Biomass Burning Plume Height

Knowledge of the injection and transport heights of biomass burning plumes is crucial for understanding the long-range transport of the particles and reactive gases that can substantially alter the radiation balance, chemistry, and climate.Remote and in-situ observations have documented many instances of biomass burning pollutants in the Upper Troposphere and Lower Stratosphere. However, the injection height of these high-altitude plumes is a large source of uncertainty in various models. Using coincident OMI aerosol index (AI) and CALIPSO height measurements, we have developed an empirical relationship between AI and injection heights for young biomass burning plumes. We hypothesize that the observed deviation for aged plumes (more than two days) is driven primarily by dilution. The Black Saturday event is an excellent case study for testing the effect of dilution on the relationship between AI and height. Since the aerosol plume stayed intact and AI observations are available for multiple days, we can examine how aging and dilution affect AI values at high altitudes. This event sheds on light on observations of less dramatic cases in Australia and worldwide.