Journal article
An intercomparison of lidar-derived aerosol optical properties with airborne measurements near Tokyo during ACE-Asia : Characterization of Asian aerosols and their radiative impacts on climate
Journal of geophysical research. Atmospheres, Vol.108(D23), pp.ACE19.1-ACE19.19
2003
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 (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 (<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 δa; and an upper layer (above ∼3.5 km) where dust dominated, giving a high δa (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.
Metrics
1 Record Views
Details
- Title
- An intercomparison of lidar-derived aerosol optical properties with airborne measurements near Tokyo during ACE-Asia : Characterization of Asian aerosols and their radiative impacts on climate
- Creators
- Toshiyuki Murayama - Tokyo University of Marine Science and TechnologySarah J Masonis - University of WashingtonAntony Clarke - University of Hawaii SystemMakoto Abo - Tokyo Metropolitan UniversityAtsushi Shimizu - National Institute for Environmental StudiesNobuo Sugimoto - National Institute for Environmental StudiesMasanori Yabuki - Chiba UniversityHiroaki Kuze - Chiba UniversityShunsuke Fukagawa - Chiba UniversityKari Maxwell-Meier - Georgia Institute of TechnologyRodney J Weber - Georgia Institute of TechnologyDouglas A Orsini - Georgia Institute of TechnologyJens Redemann - Bay Area Environmental Research InstituteByron Blomquist - University of Hawaii SystemAlan Bandy - Drexel UniversityDonald Thornton - Drexel UniversityTheodore L Anderson - University of WashingtonBeat Schmid - Bay Area Environmental Research InstituteJohn M Livingston - SRI InternationalPhilip B Russell - Ames Research CenterBarry Huebert - University of Hawaii SystemSteven G Howell - University of Hawaii SystemCameron S Mcnaughton - University of Hawaii System
- Publication Details
- Journal of geophysical research. Atmospheres, Vol.108(D23), pp.ACE19.1-ACE19.19
- Publisher
- American Geophysical Union
- Number of pages
- 19
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Chemistry; [Retired Faculty]
- Identifiers
- 991022036299004721