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

• Published in: Journal of Geophysical Research. D. Atmospheres 2003-12, Vol.108 (D23), p.n/a
• Main Authors: Murayama, Toshiyuki, Masonis, Sarah J., Redemann, Jens, Anderson, Theodore L., Schmid, Beat, Livingston, John M., Russell, Philip B., Huebert, Barry, Howell, Steven G., McNaughton, Cameron S., Clarke, Antony, Abo, Makoto, Shimizu, Atsushi, Sugimoto, Nobuo, Yabuki, Masanori, Kuze, Hiroaki, Fukagawa, Shunsuke, Maxwell-Meier, Kari, Weber, Rodney J., Orsini, Douglas A., Blomquist, Byron, Bandy, Alan, Thornton, Donald
• Format: Article
• Language: English
• Subjects: airborne measurement; Asian dust; polarization and Raman lidar
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/2002JD003259

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 (σa ∼ 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 (δa) and a negative correlation between δa and the backscattering coefficient (δa) 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 δa. 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 δa (