Shinsuke Satake

Characteristics of sulfate haze over East Asia retrieved with satellite and ground-based remote sensing data

Optical observation around near UV spectral region potentially enables us to retrieve light absorbing features of aerosol, such as type as well as optical thickness. We analyzed near UV observation data to identify haze properties around Japan in the autumn of 2003, using Global Imager onboard Advanced Earth Observing Satellite-II (ADEOS-II/GLI), which has 380nm and 400nm window channels. At the same time, we had optical observation, such as a ground-based LIDAR measurement and a shipborne skyradiometer measurement, so as to retrieve vertical profile, particle sphericity, particle size distribution, and optical thickness of the haze. Based upon the three kinds of analyses with remotely sensed data, such as satellite, LIDAR, and skyradiometer, we have the following characteristics of the haze: little UV absorbing, of optical thickness 0.5 (around 500nm), within lower boundary layer (less than around 1km a.s.l.), and of spherical and fine particles (0.2 μm in radius). We also have some direct sampling measurements onboard Research Vessel Shirase, such as integrated nephelometer, particle soot / absorption photometer, and optical particle counter, so as to identify optical and microphysical properties of the haze as well as chemical composition analyses. The results of the surface direct sampling showed the dense haze dominantly consisted of smaller (0.2 μm in radius) and sulfate particulates, which is consistent to the remotely sensed results. Backward trajectory simulations also indicate that the hazy air mass had arrived from / through some mega cities over East Asia. Further, we are going to investigate the consistency between optical, microphysical, chemical, and dynamical aspects using a chemical transport model.