Investigation of the Optical Properties of Aerosols over the Coastal Region at Dalian, Northeast China

Atmosphere

Yanjun Ma¹  Hujia Zhao¹  Yangfeng Wang¹  Xiaoye Zhang²  Huizheng Che²  Hong Wang²  Yaqiang Wang² 

[1] Institute of Atmospheric Environment, China Meteorological Administration, Shenyang 110016, China;Key Laboratory for Atmospheric Chemistry, Institute of Atmospheric Composition, Chinese Academy of Meteorological Sciences (CMA), 46 Zhongguancun South Avenue, Beijing 100081, China;

关键词: aerosol optical depth;    Ångström exponent;    coastal regions;    Northeast China;   

DOI  :  10.3390/atmos7080103

来源: DOAJ

【 摘 要 】

Measurements of the aerosol optical depth (AOD) and the Ångström exponent were retrieved from level 1.5 data obtained by the CE318 sun photometer at Dalian monitoring station from April 2007 to April 2012 to characterize the aerosol spatial and temporal characteristics in this coastal region of Northeast China. The results suggest that the highest mean ± SD value for the AOD over Dalian occurred in the month of July (0.86 ± 0.45), whereas a lower value was observed in the month of January (0.42 ± 0.31). The monthly mean Ångström exponent was at a maximum (about 1.27) in September and October and the minimum value of about 0.60 was recorded in March. The frequency distributions of the AOD and Ångström exponent at Dalian both presented a single peak distribution, with peak values of 0.26 and 1.06, respectively. The scatter grams of the AOD and Ångström exponent suggested that the aerosol size in Dalian was affected by both fine and coarse particles in different seasons. The spectral difference in Ångström exponent wavelength pairs between 440–675 and 675–870 nm indicate that high AOD440 nm values (>1.50) could be clearly identified by the fine mode growth in summer and the addition of coarse mode particles in spring over Dalian. The AOD440 nm value on a foggy day was almost 2.15 times larger than that on a day with high levels of dust. The Ångström exponents (440–870 nm) were about 0.13 and 1.46 on the days with high levels of dust and on the foggy days, respectively.

【 授权许可】

Unknown