【作者】 夏俊荣；

【导师】 张镭；

【作者基本信息】 兰州大学 ， 大气物理学与大气环境， 2006， 硕士

【摘要】 首次利用激光雷达在兰州进行系统的大气气溶胶探测。将Fernald方法与Collis斜率法结合起来,根据仪器和本地区环境特点,建立了适合于兰州地区的激光雷达观测数据资料处理分析方法。通过对雷达观测资料反演,得到气溶胶消光系数廓线,进而分析气溶胶消光系数的日变化,以及季节变化等特征。 （1） 在Fernald方法基础上,结合所用激光雷达和兰州的实际情况,重新确定了标定高度与边界值,建立了适合本地区观测分析的方法。 应用该方法,设计两种方案（方案一的S₁取20&15,方案二S₁取30）分别计算,得到气溶胶光学厚度。将由两种方案得到的气溶胶光学厚度与L97太阳光度计得到的气溶胶光学厚度进行了对比,通过统计参数验证,结果表明方案一比较合理,本文最终选用方案一。 （2） 对采集到的数据进行了处理分析,初步揭示了兰州市气溶胶消光系数垂直分布及其演变的特征。 A.典型日特征 低空气溶胶消光系数及0.195～1km之间的气溶胶光学厚度的演变趋势比较一致,中午1200最大,然后下降,晚2000降至最低,半夜又小幅回升。 低空气溶胶消光系数的演变与气象能见度演变一致。 在低空（500～1000m以下）气溶胶较多,再往上急剧减少。 B.季平均特征 夏、秋、冬季低空平均气溶胶消光系数一般都是在1200最大,然后逐渐减小,到半夜0000又回升,平均气溶胶光学厚度也有同样的演变趋势。 低空平均气溶胶消光系数在冬季最大,夏季最小,平均气溶胶光学厚度也是冬季最大,夏季最小。 秋、冬的季平均气溶胶消光系数随高度下降很快,而夏季相对趋势不明显。 C.时刻平均特征 冬季的1200、1600、2000、0000等各时刻低空平均气溶胶消光系数最大,夏季的最小;而到了1.5km高度以上,反而是夏季的最大,冬季的最小。更多还原

【Abstract】 The aerosol properties were measured systemically by a lidar in Lanzhou for the first time. The paper combined the Fernald method and the Collis slope method and developed a new data processing method based on the instrument and the local environment conditions. The aerosol extinction coefficient profile was retrieved through the lidar observation data, and the daily and seasonal variations of the aerosol extinction coefficient were analyzed. The main contents were as follows.（1） A new method to process the lidar data based on the Fernald method which was considered from the instrument and the local environmental conditions was developed, and the new method built another way to set the calibration altitude as well as the boundary condition.Applying the method, the AOD （aerosol optical depth） by two different schemes （set S₁ as 20&15, and as 30, respectively） was calculated, and then compared theresults with the AOD derived from L97 sunphotometer, it showed that the former scheme was more reasonable, and that was the very one which we adopted.（2） By processing the lidar data, the characteristics of aerosol extinction coefficient vertical distribution and evolution were revealed primarily.A. Typical day characteristicsThe trends of the low level aerosol extinction coefficient was agreement with that of the AOD, both of them reached the maximum at 1200 （Beijing Time）, then declined, and reached the minimum at 2000, and finally rose a bit at midnight.The trend of the low level aerosol extinction coefficient was in accord with that of visibility.The aerosol concentration was mainly distributed in low level （below 500¹000m）, and it decreased greatly with altitude.B. Seasonal characteristicsIn summer, fall, and winter, the low level mean aerosol extinction coefficient usually reached the maximum at 1200, then decreased gradually, but finallyrebounded slightly at midnight, so did the mean AOD.The maximum of low level mean aerosol extinction coefficient occurred in winter, and the minimum occurred in summer and so did the mean AOD.The mean aerosol extinction coefficient decreased rapidly with altitude in fall and winter, but the trend was not significant in summer.C. Mean daily characteristicsThe low level mean aerosol extinction coefficient reached the maximum in winter, minimum in summer at 1200, 1600, 2000 and 0000;but the maximum of the mean aerosol extinction coefficient appeared in summer, the minimum in winter above 1.5km level.D. A snowstorm procedureThe low level aerosol extinction coefficient was comparative large before the snowstorm procedure, with the AOD of about 0.408 between 0.195⁵km level;after the snow, the low level aerosol extinction coefficient decreased significantly, with the AOD of about 0.205 between 0.195⁵km level.This study would help to understand deeply the optical properties of aerosol, and it would be of benefit to the researches of aerosol radiative forcing and climate response.更多还原