Distributions and optical characteristics of aerosols were continuously observed with a polarization-sensitive (532 nm), Mie-scattering (532 and 1064 nm) and Raman-scattering (607 nm) lidar and a sky radiometer in Phimai, Thailand. Polarization lidar measurements indicated that high concentration plumes of spherical aerosols considered as biomass burning smoke were often observed in the dry season. Plumes of non-spherical aerosols considered as long-range transported soil dust from Africa, the Middle East, or Northeast Asia were occasionally observed. Furthermore, low-concentration non-spherical aerosols were almost always observed in the atmospheric mixing layer. Extinction coefficient profiles of spherical aerosols and non-spherical dust exhibited different diurnal variations, and spherical aerosols including smoke were distributed in higher altitudes in the mixing layer and residual layer. The difference can be explained by hygroscopic growth of smoke particles and buoyancy of the smoke. Analysis of seasonal variations of optical properties derived from the Raman lidar and the sky radiometer confirmed that the lidar ratio, aerosol optical depth, and Angstrom exponent were higher in the dry season (October–May) and lower in the wet season (June–September). The single scattering albedo was lower in the dry season. These seasonal variations are explained by frequent biomass burning in the dry season consistent with previous studies in Southeast Asian region. At the same time, the present work confirmed that soil dust was a major aerosol component in Phimai, Thailand.
National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan;National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan;National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan;National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan;National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan;Center for Environmental Remote Sensing, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 268-8522, Japan;Center for Environmental Remote Sensing, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 268-8522, Japan;Center for Environmental Remote Sensing, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 268-8522, Japan;University of Toyama, 3190 Gofuku, Toyama 930-8555, Japan;Department of Geology, Faculty of Science, Chulalongkorn University, Phayathai Rd, Phathumwan district, Bangkok 10330, Thailand
Recommended Citation:
Nobuo Sugimoto,Atsushi Shimizu,Tomoaki Nishizawa,et al. Aerosol characteristics in Phimai, Thailand determined by continuous observation with a polarization sensitive Mie–Raman lidar and a sky radiometer[J]. Environmental Research Letters,2015-01-01,10(6)