This study focused on the observation of aerosol optical properties in the northern suburb of Nanjing based on three-wavelength photo-acoustic soot spectrometer (PASS-3).The calibration experiments of the scattering and absorption coefficient(Bsca and Babs) measured by PASS-3 were carried out.The inter-comparison of instruments was designed to measure the Bsca and Bsbs for the reliability of PASS-3.The instruments involved PASS-3,Nephelometer (TSI 3563) and Aethalometer (AE-31).Finally,17 days of field observation were carried out by using PASS-3 in the spring of the northern suburb of Nanjing.The reliability experiment showed the measurement results of PASS-3 corrected very well with Nephometer and Aethalometer.The observation results showed:the Bsca of spring aerosol in northern suburb of Nanjing were higher than the other sites of China while the Babs were lower than the sites;the diurnal variation of Bsca and Babs showed the bimodal distribution.The single scattering alebedo (ω532) had the minimum values at 7:00 and 19:00.The hourly average ω532 was 0.89±0.04.The (A)ngstr(o)m scatter exponent (Asca) had the minimum value in the morning and stard to increase in the afternoon,but (A)ngstr(o)m absorption exponent(Aabs) had no obvious diurnal variation.The average Asca and Aabs during sampling period were 1.50 ±-0.31 and 1.29-±-0.59.The results indicated the meteorological factors such as wind seed,relative humidity,and the distribution of emission sources were the main causes of the aerosol optical properties variation in the spring of sampling site.%利用三波长黑碳光声光度计(PASS-3)对南京北郊气溶胶的光学特性进行观测研究.先对PASS-3测量的气溶胶的散射和吸收系数进行校准,再用传统测量气溶胶光学特性的TSI 3563积分浊度仪和AE-31黑碳仪对PASS-3的可靠性做了验证,最后利用PASS-3对南京北郊春季气溶胶开展了为期17 d的外场观测.结果表明,PASS-3与TSI3563积分浊度仪对气溶胶散射系数的测量结果和AE-31黑碳仪对吸收系数的测量结果的相关性较高.观测结果表明,南京北郊春季气溶胶散射系数的平均值略高于国内其他观测点的相应值,而吸收系数平均值则低于相应站点,二者的日变化都呈双峰特征;532 nm处单散射反照率(ω532)在7:00和19:00出现极小值,其平均值为(0.89土0.04);气溶胶Angstr(o)m散射指数上午出现极小值,下午开始增大,而Angstr(o)m吸收指数则没有明显的日变化特征,二者观测期间平均值分别为(1.50±0.31)和(1.29±0.59).分析表明,风速、相对湿度等气象因素以及观测点周边污染源的分布特点是造成南京北郊春季气溶胶光学特性变化的主要因素.
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