摘要
采用兰州大学半干旱气候和环境观测站(SACOL)2007年11月1日至2008年10月31日的APS-3321粒径谱仪的连续观测资料,对该地区大气颗粒物的浓度变化和粒径分布特征进行分析研究。结果表明,该地区颗粒物浓度年变化呈单峰值型,无论是数浓度还是质量浓度峰值均出现在12月,数浓度6月最低,质量浓度9月最低;和其他地区相比,无论数浓度还是质量浓度,均低于污染较严重的城市,但高于内陆清洁地区。数浓度和质量浓度平均日变化均呈单峰值型,都在上午11:00BST左右达到峰值,下午18:00BST左右达到谷值,但质量浓度峰值出现时间随季节而有所差异。颗粒物浓度的年变化和背景风场主导风向的年际变化有一定关系,而局地垂直风速及水平风向的昼夜转换对颗粒物浓度的日变化有较大的影响。数浓度粒径谱分布特征呈单峰值型,主要集中在0.673μm左右;质量浓度粒径谱分布特征呈双峰值型,第一个峰值出现在0.777μm左右,第二个峰值出现在5.048μm左右。降水对大于1μm的粒子的去除效果非常明显。当沙尘天气发生时,数浓度和质量浓度与背景天气条件下相比增大了22%和127%。
Based on the continuous measurements with APS-3321 from November 1st, 2007 to October 31st, 2008 at Semi-Arid Climate and Environment Observatory of Lanzhou University （SACOL）, the characteristics of particle concentration and the size distributions were studied. The results are as follows. The annual variation of the number concentration and mass concentration are single-peak, and the peaks of both types of concentrations appear in December. The number concentration reaches the valley point in June and the minimum mass concentration appears in September. Compared with other regions, both types of concentration over this area are less than that over urban area, but higher than that over clean inland regions. The diurnal variation of both types of concentrations is single-peak with the maximum appears around 11：00 BST and the minimum at about 18：00 BST. The time of mass concentration summit varies in different seasons. The annual variation of particle concentration is greatly related to annual shift of dominant wind direction between SE and NW. The daily variation of local vertical wind velocity and wind direction greatly affects the daily variation of particle concentration. The size distribution of number concentration is unimodal type and most of particles are centralized at 0.673μm or so. The size distribution of mass concentration has two peaks and the first peak appears near 0.777μm, and the second appears near 5.048μm. Precipitation is a very important factor scavenging particles with diameter larger than 1μm. Under dust weather condition, the number concentration and mass concentration increases by 22% and 127% respectively.
出处
《中国沙漠》
CSCD
北大核心
2010年第5期1186-1193,共8页
Journal of Desert Research
基金
国家自然科学基金重点项目(4063317)资助
关键词
大气颗粒物
质量浓度
数浓度
粒径谱分布
气象条件
atmospheric particles
mass concentration
number concentration
size distribution
weather condition
