Seasonal Aerosol Optical Properties at Anmyon-do Global Atmosphere Watch Observatory, Korea

Aerosol light scattering, hemispheric backscattering, and absorption properties measured continuously at the Anmyon-do in Korea covering the 5-year period from 1999 to 2003, including the Asian Pacific Regional Aerosol Characterization Experiment have been analyzed to determine the seasonal variation and to clarify long-range transport of dust aerosol from the Asian desert to Korea. Daily and monthly statistics have been calculated. The median scattering, σ sp , and back-scattering, σ bsp , were 86 Mm?¹ and 10 Mm?¹ at 550 ㎚ for the 5-year period, respectively. The median aerosol absorption, σ ap , was 12 Mm?¹ at 880 ㎚. The median σ sp is largest in spring, while the median σ ap is largest in late summer and fall. Seasonally-averaged backscattering ratio at 550 ㎚ was high in spring, but Ångstrom exponent was low in spring with increasing particle size. A comparison of optical properties between Asian dust and non-Asian dust input periods has been analyzed. During Asian dust events, the scattering coefficient for 450, 550, and 700-㎚ wavelength increased by a factor of 4.2 to 4.7, but the absorption coefficient changed little. Backward trajectory analysis suggests that the long-range transport of dust might be important for determining the σ sp .