塔克拉玛干沙漠腹地沙尘气溶胶质量浓度的观测研究

Observation study on mass concentration of dust aerosols in the Taklimakan Desert Hinterland

对塔克拉玛干沙漠腹地塔中地区进行了长达6a的试验观测研究,获得了该地区沙尘气溶胶的基本特征:塔中地区浮尘、扬沙出现日数呈上升趋势,而沙尘暴日数呈下降趋势,沙尘天气出现的频率和强度是影响沙漠地区沙尘气溶胶浓度的主要因素.可吸入颗粒物(PM10)月平均质量浓度峰值区分布在春夏两个季节,3～5月是主峰值区域,7～8月是次峰值区,春季PM10平均浓度在1000μg/m3左右变化,夏季在400～900μg/m3之间,秋冬两季浓度较低基本上在200～400μg/m3之间变化.每年的3～9月是总悬浮颗粒物(TSP)质量浓度较高的月份,4～5月是主峰值区,7～8月为次峰值区;2005年TSP质量浓度最低,年平均值为1105.0μg/m3,2009年略高于2008年,年平均浓度为1878.0μg/m3,2008年5月TSP平均质量浓度是全年最高值,浓度值达到7415.0μg/m3.沙尘天气过程中大气颗粒物浓度变化具有以下规律:晴天<浮尘天气<浮尘、扬沙天气<沙尘暴天气.风速大小直接影响大气中颗粒物浓度,风速越大颗粒物浓度越高.气温、相对湿度和气压是影响沙尘暴强度的重要因素,也间接影响大气中颗粒物浓度的变化.

An over 6 years dust aerosol investigation had been carried out in Tazhong area of Taklimakan Desert hinterland,which is one of the most important dust sources in China.The fundamental characteristics of dust aerosol＇s concentration were summarized as below： the floating and blowing dust appeared an increasing tendency in day time,meanwhile,the sandstorm appeared a decreasing tendency.The frequency and intensity dust weather were major factors which were significantly affected the concentration of dust aerosols in the desert region.The monthly peak values of PM10 concentration distributed in spring and summer： the largest peak value range was between March to May and the second peak value range occurred between July to August.Average concentration of PM10 varied around 1000μg/m3 in spring and changed between 400 to 900μg/m3 in summer.Lower concentrations appeared in autumn and winter with about 200～400μg/m3.The TSP concentration was higher between March and September.The largest peak value range of TSP concentration was between April to May and the second peak value range occurred between July to August.The lowest TSP concentration took place in 2005 with the annual average of 1105.0μg/m3.The TSP concentration value was slightly higher in 2009 than in 2008 with annual average of 1878.0μg/m3.And the monthly average concentration of TSP in May was the highest with the value of 7415.0μg/m3.The mass concentration increased with the following sequences in the sandstorm weather： sunshine,floating dust,blowing dust and sandstorm.Wind speed had the influential role to mass concentration,and the higher speed of wind was,the higher mass concentration was.The temperature and air humility were also the driving forces of sandstorm intensity,which were indirectly influence the mass concentration variation as well.