Optical properties of biomass burning aerosols during Russian forest fire events in 2010

Abstract

This work intends to develop an algorithm for aerosol retrieval based on the combined use of CAI (Cloud aerosol imager) on the satellite GOSAT and POLDER (Polarization and directionality of Earth's reflectances) on PARASOL. The CAI measures the total intensity at 0.380, 0.674 and 0.870 μm. The measurements at 0.380 μm have an advantage for detecting the absorbing aerosols, such as carbonaceous as well as dust aerosols. On the contrary, POLDER provides the multi directional polarization information at 0.670 and 0.865 μm. The polarization information is useful to retrieve aerosol characteristics over land because the polarization by the land surface is much smaller than the total one. Our algorithm is mainly based on the radiative transfer calculations in the Earth atmosphere model involving various kinds of atmospheric particles. This algorithm is applied for the Russian forest fire events happened in summer of 2010. As results, aerosol optical thickness (AOT), Angstrom exponent and single scattering albedo (SSA) are retrieved. The retrieved results are partially validated with ground based measurements of AERONET. It is found that AOT takes the values of ~2 all over the event region and larger than ~5 over the plume core. The particle size information retrieved as Angstrom exponent indicates the existence of small aerosols in the plume. The SSA takes the lower value of ~0.85, especially lower in the edge of plume than at the plume core. This fact might suggest the changing of particle property by water vapor uptake during transport.