黄土高原半干旱区气溶胶光学特性季节变化特征  

Seasonal variation of aerosol optical properties at AERONET of the semi-arid region in Loess Plateau

作　　者：白鸿涛 陈勇航[3] 王洪强[3] 张强[1] 郭铌[1] 王胜[1] 潘鹄[3] 张萍[3] 

机构地区：[1]中国气象局兰州干旱气象研究所,甘肃兰州730020 [2]江西省减灾备灾中心,江西南昌330046 [3]东华大学环境科学与工程学院,上海201620

出　　处：《干旱区地理》2011年第2期292-299,共8页Arid Land Geography

基　　金：国家自然科学基金(40830957);国家科技支撑计划重点项目(2008BAC40B04);干旱气象科学研究基金项目(IAM200807)资助

摘　　要：采用AERONET Version 2 Level 2.0气溶胶数据集,分析了光学厚度、Angstrom波长指数、粒子尺度体积谱分布(dV(r)/dlnr)、折射指数(n-ik)和单次散射反照率(ω0)等大气气溶胶光学特性参数的季节变化特征以及光谱依赖性。结果表明:气溶胶特性参量均具有明显的季节变化且呈现出明显的受沙尘影响的特征,春季受沙尘影响最明显,光学厚度最大;冬季受采暖和沙尘的共同影响,光学厚度也较大。气溶胶粒子体积尺度谱分布的主要差别体现在粗模态粒子体积浓度上,粗模态体积浓度呈现明显的季节变化规律:春季>冬季>夏季>秋季,与粗细粒子体积浓度比和光学厚度变化一致,说明该地区光学厚度的季节变化主要是由于粗模态体积浓度不同造成的。另外,粗模态体积中值半径也存在明显的季节变化:冬季>秋季>夏季>春季。折射指数实部和气溶胶粗粒子体积浓度与光学厚度的季节变化规律一致,而折射指数虚部冬季最大,春季最小;单次散射反照率随季节的变化规律有很大不同,冬季最小,而春季最大,可能与气溶胶粒子尺度及其化学组成的综合作用有关。Semi-arid regions are defined as transition zones between arid and sub-humid belts where precipitation is less than the potential evaporation.Semi-arid lands,especially those located in mid-latitude inner continental regions,are some of the most sensitive areas to climate change.One of these regions is found in western China.During the last few decades,warm winters and dry springs occurred more frequently in northwestern China where,with disturbances brought about by human activity,large areas of vegetation were destroyed,thus giving rise to anthropogenic dust emissions.Understanding how human activity and the resulting dust emissions affect aerosol optical properties in these semi-arid regions is an essential step for developing mitigation and adaptation strategies to climate changes in these transition areas.In order to monitor the global aerosol optical properties,the U.S.space agency NASA and its partners established a worldwide network of ground-based observationswhich is an international aerosol automatic monitoring network called AERONET(Aerosol Robotic Network).The sun and sky diffuse radiation was measured and thene the aerosol optical properties are retrieved by using the sun and sky scanning spectral radiation observations.The products from the AERONET direct sun and sky radiance measurements are retrived through a rigorous calibration,cloud mask processing,and quality control.In this paper,the impact of dust aerosols on the semi-arid climate of northwestern China was analyzed using Version 2 Level 2 dataset from the AERONET site located in the semi-arid region in Loess Plateau in China,which is named as Lanzhou_city site.The seasonal variation of parameters of atmospheric aerosol optical properties such as aerosol optical thickness,Angstrom exponent,volume size distribution(dV(r)/dlnr),refractive index(n-ik) and single scattering albedo(0) were analyzed.The results show that the optical properties of the dust aerosols and aerosols generated by human activities have become apparently great effect on th

关 键 词：沙尘气溶胶 光学特性 季节变化 

分 类 号：X513[环境科学与工程—环境工程]