Asian dust outflow in the PBL and free atmosphere retrieved by NASA CALIPSO and an assimilated dust transport model Y. Hara1, K. Yumimoto2, I. Uno2, A. Shimizu1, N. Sugimoto1, Z. Liu3, and D. M. Winker4 1National Institute for Environmental Studies, Tsukuba, Ibaraki, Japan 2Research Institute for Applied Mechanics, Kyushu University, Fukuoka, Japan 3National Institute of Aerospace, Hampton, VA 23666, USA 4NASA Langley Research Center, Hampton, VA 23681, USA
Abstract. Three-dimensional structures of Asian dust transport in the planetary
boundary layer (PBL) and free atmosphere occurring successively during the
end of May 2007 were clarified using results of space-borne backscatter
lidar, Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and
results obtained using a data-assimilated version of a dust transport model
(RC4) based on a ground-based NIES lidar network. The dust layer depths and
the vertical and horizontal structure simulated by RC4 agreed with those of
CALIOP observations from the dust source region to the far-downstream
region. Two important transport mechanisms of Asian dust in the PBL and free
atmosphere were clarified: a low-level dust outbreak within the dry slot
region of a well-developed low-pressure system, and formation of an elevated
dust layer within the warm sector of a low-pressure system. We also
represent the aging of pure dust particles using the particle depolarization
ratio (PDR) at 532 nm and the color ratio (CR) at 1064 nm and 532 nm.
Aerosols with high PDR were observed uniformly over the dust source region.
While the dust cloud was transported to the eastern downwind regions,
aerosols with low PDR and high CR occur in the layer of less than 1 km
height, suggesting a mixing state of spherical aerosols and dust in the
Citation: Hara, Y., Yumimoto, K., Uno, I., Shimizu, A., Sugimoto, N., Liu, Z., and Winker, D. M.: Asian dust outflow in the PBL and free atmosphere retrieved by NASA CALIPSO and an assimilated dust transport model, Atmos. Chem. Phys., 9, 1227-1239, doi:10.5194/acp-9-1227-2009, 2009.