An intercomparison of lidar-derived aerosol optical properties with airborne measurements near Tokyo during ACE-Asia

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Read Full Article (file size: 1470942 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. D23, 8651, doi:10.1029/2002JD003259, 2003 An intercomparison of lidar-derived aerosol optical properties with airborne measurements near Tokyo during ACE-Asia Toshiyuki Murayama Tokyo University of Mercantile Marine, Tokyo, Japan Sarah J. Masonis Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA Jens Redemann Bay Area Environmental Research Institute, Sonoma, California, USA Theodore L. Anderson Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA Beat Schmid Bay Area Environmental Research Institute, Sonoma, California, USA John M. Livingston SRI International, Menlo Park, California, USA Philip B. Russell NASA Ames Research Center, Moffett Field, California, USA Barry Huebert Department of Oceanography, University of Hawaii, Honolulu, Hawaii, USA Steven G. Howell Department of Oceanography, University of Hawaii, Honolulu, Hawaii, USA Cameron S. McNaughton Department of Oceanography, University of Hawaii, Honolulu, Hawaii, USA Antony Clarke Department of Oceanography, University of Hawaii, Honolulu, Hawaii, USA Makoto Abo Department of Electrical Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan Atsushi Shimizu Atmospheric Environment Division, National Institute of Environmental Studies, Tsukuba, Japan Nobuo Sugimoto Atmospheric Environment Division, National Institute of Environmental Studies, Tsukuba, Japan Masanori Yabuki Center for Environmental Remote Sensing, Chiba University, Chiba, Japan Hiroaki Kuze Center for Environmental Remote Sensing, Chiba University, Chiba, Japan Shunsuke Fukagawa Center for Environmental Remote Sensing, Chiba University, Chiba, Japan Kari Maxwell-Meier School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA Rodney J. Weber School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA Douglas A. Orsini School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA Byron Blomquist Department of Oceanography, University of Hawaii, Honolulu, Hawaii, USA Alan Bandy Department of Chemistry, Drexel University, Philadelphia, Pennsylvania, USA Donald Thornton Department of Chemistry, Drexel University, Philadelphia, Pennsylvania, USA Abstract During the ACE-Asia intensive observation period (IOP), an intercomparison experiment with ground-based lidars and aircraft observations was conducted near Tokyo. On 23 April 2001, four Mie backscatter lidars were simultaneously operated in the Tokyo region, while the National Center for Atmospheric Research C-130 aircraft flew a stepped-ascent profile between the surface and 6 km over Sagami Bay southwest of Tokyo. The C-130 observation package included a tracking Sun photometer and in situ packages measuring aerosol optical properties, aerosol size distribution, aerosol ionic composition, and SO₂ concentration. The three polarization lidars suggested that the observed modest concentrations of Asian dust in the free troposphere extended up to an altitude of 8 km. We found a good agreement in the backscattering coefficient at 532 nm among lidars and in situ 180° backscatter nephelometer observations. The intercomparison indicated that the aerosol layer between 1.6 and 3.5 km was a remarkably stable and homogenous in mesoscale. We also found reasonable agreement between the aerosol extinction coefficients (σ_a ∼ 0.03 km⁻¹) derived from the airborne tracking Sun photometer, in situ optical instruments, and those estimated from the lidars above the planetary boundary layer (PBL). We also found considerable vertical variation of the aerosol depolarization ratio (δ_a) and a negative correlation between δ_a and the backscattering coefficient (δ_a) below 3.5 km. Airborne measurements of size-dependent optical parameters (e.g., the fine mode fraction of scattering) and of aerosol ionic compositions suggests that the mixing ratio of the accumulation-mode and coarse-mode (dust) aerosols was primarily responsible for the observed variation of δ_a. Aerosol observations during the intercomparison period captured the following three types of layers in the atmosphere: a PBL (surface to 1.2–1.5 km) where fine (mainly sulfate) particles with a low δ_a (<10%) dominated; an intermediate layer (between the top of the PBL and 3.5 km) where fine particles and dust particles were moderately externally mixed, giving moderate δ_a; and an upper layer (above ∼3.5 km) where dust dominated, giving a high δ_a (30%). A substantial dust layer between 4.5 and 6.5 km was observed just west of Japan by the airborne instruments and found to have a lidar ratio of 50.4 ± 9.4 sr. This agrees well with nighttime Raman lidar measurements made later on this same dust layer as it passed over Tokyo, which found a lidar ratio of 46.5 ± 10.5 sr. Received 30 November 2002; accepted 19 May 2003; published 29 August 2003. Index Terms: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 3360 Meteorology and Atmospheric Dynamics: Remote sensing; 9320 Information Related to Geographic Region: Asia. Read Full Article (file size: 1470942 bytes) Cited by Citation: Murayama, T., et al. (2003), An intercomparison of lidar-derived aerosol optical properties with airborne measurements near Tokyo during ACE-Asia, J. Geophys. Res., 108(D23), 8651, doi:10.1029/2002JD003259. Copyright 2003 by the American Geophysical Union.

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