摘要
利用CE-318太阳光度计在内蒙古额济纳旗、东胜、锡林浩特三地观测的2002年6月—2003年5月间的太阳直接辐射数据,应用消光法反演大气气溶胶光学厚度[AOT(λ),Aerosol OpticalThickness]和粒子谱分布,并分析其变化特征。结果表明,该地区气溶胶光学厚度具有明显的时空变化:春季最大,冬季最小,AOT(λ=440 nm)平均最大值为0.78,最小值为0.13。3个观测点中,额济纳旗的光学厚度最大,东胜最小。光学厚度的日变化主要有4种形式:1)早晨高傍晚低;2)早晨低傍晚高;3)早晚低中午高;4)变化平缓。这主要与沙尘天气的发生、大气层结稳定度和人类活动等因素有关。气溶胶粒子谱分布基本符合Junge谱,在粒径0.3μm、0.6μm和1.0μm处出现峰值。但是在不同天气条件下粒子谱有很大差异,在沙尘暴天气中,大粒子和巨粒子数有明显的增加,粒子数浓度要比晴天背景大气大了约一个量级。春季气溶胶粒子数浓度最大,夏秋季次之,冬季最小,但相差不超过一个量级。
By using the direct solar radiation data measured by a CE-318 sun photometer in Inner Mongolia during the period between June 2002 and May 2003 ,the aerosol optical thickness （AOT） and size distribution were retrieved by extinction method. Results show that there were significant variations in temporal-spacial distributions of AOT. The largest mean AOT appeared in spring[ AOT（ λ =440 nm） =0.78 ] with the least in winter[ AOT（λ =440 nm） =0.13]. AOT was always largest in Ejin Qi and least in Dongsheng. There were four patterns of day-time variations： （ 1 ） AOT is high in the morning and low in the evening;（2） AOT is low in the morning and high in the evening;（3 ）AOT peaks at noon; （4）AOT varies gently. This is mainly associated with dust weather, turbulence of boundary layer and human activities. The aerosol size distribution basically satisfied the Junge distribution and appeared an obvious peaks at r = 0.3 μm,0.6 μm,and 1.0 μm. However,it shows a significant discrepancy under different weather conditions. Large dust particles and giant dust particles remarkably increased in dust weather. The aerosol number concentration in dust weather was about one order of magnitude larger than that in clean weather. And it was also larger in spring than that in winter, but the both were still within the same order of magnitude.
出处
《南京气象学院学报》
CSCD
北大核心
2006年第6期775-781,共7页
Journal of Nanjing Institute of Meteorology
基金
教育部高等学校博士点基金资助项目(20050300002)
国家自然科学基金资助项目(40365002)
江苏省气象灾害重点实验室资助项目(KLME05006)
