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Seasonal Variations of Aerosol Optical Properties in Qingdao

Author: ChenJingJing
Tutor: ShengLiFang
School: Ocean University of China
Course: Meteorology
Keywords: Aerosol Optical parameters Volume spectrum Sky radiometer Horizontal visibility Relative humidity
CLC: X513
Type: Master's thesis
Year: 2008
Downloads: 118
Quote: 1
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Abstract


Aerosol through direct and indirect two ways to affect the climate system, also has an important impact on ambient air quality and human health. Study of atmospheric aerosols climate and environmental effects must fully understand the aerosol particle size distribution, chemical composition and optical properties, including direct observation and study of the atmospheric aerosol optical properties is very urgent research content, the calculation results can mode aerosol forcing estimates and projections of climate change and its environmental effects of the necessary parameters. Qingdao is located in the southern part of Shandong Peninsula, surrounded on three sides by the sea, is one of the important coastal city in China, is the transition zone of the subtropical and temperate to both monsoon climate and ocean climate characteristics, unique geographical location and climate make Qingdao atmospheric aerosols by the combined effect of continents and oceans, research Qingdao Atmospheric Aerosol Optical Properties seasonal changes of great significance to understand of Qingdao and land and sea border areas of the environment and the impact of aerosols on climate. Calculated from April 2002 to December 2006, spring, summer, autumn and winter seasons of 156 sunny weather in the mountains of China Ocean University campus Eight multi-band sky radiometer observations of direct solar radiation and diffuse radiation, under the aerosol optical depth (Aerosol Optical Depth, AOD), single scattering albedo (Single Scattering Albedo SSA)? ngstr? m turbidity coefficient, the wavelength index, complex refractive index and particle size spectrum, combined with ground-based meteorological observations comprehensive analysis of Qingdao Seasonal variation of aerosol optical characteristics and influencing factors. Studies have shown that Qingdao Seasonal variation of aerosol optical properties have some common characteristics, namely: the aerosol optical thickness decreases with increasing wavelength, the season most of the daily averages of less than 0.7, the date change to morning and afternoon high the type-based; each season single scattering albedo reflects the strong scattering effect and significantly positive correlation with relative humidity; refractive index of the real part and the imaginary part is not obvious variation with wavelength, according to the Mie scattering theory approximate do not think the wavelength dependence of the complex refractive index of the average of each season is about m ~ = 1.51? 0.01i; Aitken modal the volume spectrum shows the distribution of the particle size increases rapidly growing trend; season particle spectrum distribution in the accumulation mode between 0.1-0.3 first peak; aerosol optical thickness and the measured level of visibility substantially opposite trend, the season 500nm aerosol optical thickness gt; 1.0, visibility mostly in the 10.0km, optical thickness lt; 0.5, most of the visibility in more than 10.0km; each season 08 and 14 relative humidity and visibility inverse relationship. The results show that the seasonal variations of aerosol optical parameters showed more differences: abundant type of diurnal variation of aerosol optical depth in spring, most of the day average optical thickness between 0.3-0.5 by dust and continental pollution transport factors, seasonal average optical thickness; season average single scattering albedo showed a decreasing trend with wavelength, 500 nm band single scattering albedo of 0.909, with summer and winter value; season average turbidity coefficient at the Four Seasons the largest average daily turbidity coefficient between 0.2 and 0.3 the peak frequency; season average wavelength index at the Four Seasons smallest (0.862), the average wavelength index appears in the two intervals of 1.1-1.2,0.8-0.9, more particle size distribution than the rich; the season average complex refractive index of the real part of the summer and autumn than in winter, the imaginary part at the Four Seasons minimum; particle spectra show three peaks distribution, and the first peak is lower than the second, and the third peak , indicating that the the spring modes of fine particles, coarse mode particles are more accumulation state the number of particles, may be related to the spring by the Bureau of dust or exogenous dust. Dust weather conditions, the particle spectrum peak in the accumulation mode is shifted to larger particle size and the modal aerosol content of fine particles and coarse particles is increased, the two aspects will cause dust weather conditions aerosol optical thickness increases, the wavelength decreases exponentially. Summer 14-day aerosol optical parameter data in just one day for July inversion results, others are values ??in June, the summer aerosol optical properties basically reflects the average results for the month of June . Contaminated aerosols in the coastal accumulation of gas-particle into the formation of secondary aerosols, hygroscopic aerosol particles in the lower troposphere hygroscopic growth and China's east coast frequent biomass burning factors, the average optical thickness of the summer season at the Four Seasons the highest daily average optical thickness between 0.5-0.7 appears the most; 500 nm band single scattering albedo of 0.910, with the spring and autumn size;? ngstr? m the turbidity coefficient after the spring, mostly in 0.2 -0.4 summer (June) season average wavelength index at the Four Seasons, most of the average wavelength index between 1.1 and 1.6; complex refractive index of the real part of the smallest at the Four Seasons, the size of the imaginary part after the fall; The volume spectrum Movement trimodal, the first peak is higher than the second, and the third peak, indicating the number of summer accumulation mode particles is higher than the modal number of fine particles and coarse particles. Autumn and winter atmosphere is relatively clean, the season average optical thickness is lower than in the spring and summer, mostly in autumn day average aerosol optical thickness less than 0.7, less than 0.3 Weather highest frequency; season average single scattering albedo at the Four Seasons in the lowest (0.886), the scattering effect of the aerosol particles is less than other seasons;? ngstr? m the turbidity coefficient in lt; higher frequency within the range of 0.20, the wavelength of the highest frequency index between 1.3-1.4; complex refractive index of the real part of the relative spring and the winter small imaginary part in the Four Seasons, autumn aerosol particles of solar radiation absorption effect is more obvious than the other seasons; the volume spectral distribution characteristics similar to the summer. Winter average optical thickness at the Four Seasons in the lowest daily average mostly below 0.5; 500 nm single-scattering albedo and the spring and summer in size; season the average? Ngstr? M turbidity coefficient at the Four Seasons in the lowest, most lt ; 0.20, most of the wavelength exponent between 1.3-1.4; complex refractive index of the real part, the imaginary part is small compared to the summer and autumn over the summer and autumn, winter aerosol particles scattering ability in the summer season; winter volume spectrum showing a two-peak distribution, and the first peak is lower than the second peak, the modes of the winter fine particles, coarse mode particles than the accumulation of a number of state particles, which may be winter coal and other fuel combustion.

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CLC: > Environmental science, safety science > Environmental pollution and its prevention > Atmospheric pollution and its control > Particulate pollutants
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