| 贺千山 ,毛节泰. 2005. 北京城市大气混合层与气溶胶垂直分布观 测研究[J]. 气象学报, 63(3):374-384, doi:10.11676/qxxb2005.038 |
| 北京城市大气混合层与气溶胶垂直分布观 测研究 |
| OBSERVATION OF URBAN MIXED LAYER AT BEIJING USING A MICRO PULSE LIDAR |
| 投稿时间：2004-03-10 修订日期：2004-06-07 |
| DOI：10.11676/qxxb2005.038 |
| 中文关键词: 微脉冲激光雷达，混合层高度，反演方法，日季变化 |
| 英文关键词:Micro pulse lidar, Mixed layer height, Retrieval method, Diurnal and seasonal variation. |
| 基金项目:教育部博士点基金“激光雷达监测北京城市大气气溶胶垂直分布特征研究 ” (20030001091) 和《国家重点基础研究发展规划》项目:首都北京及周边地区大气、水、土环境污染机理与调控原理(G1999045700) |
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| 中文摘要: |
| 2002年3～10月在北京大学利用微脉冲激光雷达（MPL）观测了气溶胶时空变化。提出一种反演混合层高度的方法，这种方法减小了仪器订正的误差，反演的混合层高度与探空测量结果 有很好的一致性。利用该方法计算了观测期间晴天无云天气条件下的混合层高度，分析了混合层高度及其增长率的日变化、季节变化，初步研究了混合层高度和近地面气溶胶分布的相互关系，分析了表征大气扩散能力的通风系数的日变化。结果表明，利用MPL监测城市混合 层是可行的和优越的。 |
| 英文摘要: |
| About one year characteristics of the mixed layer was observed by an eyesafe, compact Micro Pulse Lidar (MPL) at Peking University. A retrieval method of the Mixed Layer Height (MLH) which reduces error of instrument correction is presented. Three case studies were carried out using the data observed on 24 Mar, 4 Apr and 18 Apr 2002. Comparisons were made between the new method calculations, the results of the retrieval method developed by Hoff et al. (1996) and the raw insonde data. The results showed that MLH derived from lidar data using the norm alized first derivative method agrees well with that from rawinsonde data. The c orrelation coefficient and rms errors that characterize the MLH retrievals with the new method and the rawinsonde data in Beijing were 0.94 and 99.4 m; with the first derivative method and the rawinsonde data, they were 0.47 and 310.4 m, re spectively. MLH and its growth rate under clearness and cloudless condition were estimated from the MPL measurement. The characteristics of diurnal and seasonal variation of MLH were derived with the data set，including the relation between the aerosol mass concentration and MLH, the diurnal variation of ventilation co efficient. The results were as follows: Annual variation of monthly mean maximum mixing depth (MMD) and the growth rate accorded with a double cycle pattern, th at was, the minimum value of monthly mean MMD and growth rate occurred in October, but the maximum value of them occurred in May and September. The phase of annual variation of monthly mean growth rate was almost consistent with that of annu al variation curve of monthly mean MMD. This showed that their positive correlation was remarkable. However, the annual variable tendency of the time mixing depth reached maximum was different from that of monthly mean MMD. In other words, the surface heat flux was a primary factor affecting MMD. The development of the mixed layer exhibited temporal behavior similar to that of the aerosol optical thickness calculated from the lidar measurement using the Klett method. It can be concluded from the diurnal variation of ventilation coefficient that the varia tions in ventilation coefficient followed more closely with the variations in av erage wind than those in mixing depth. Some relations between several parameters about mixed layer were obtained from backscatter of lidar. This work also demon strated that a MPL is quite useful and predominant for long-term monitoring of the urban mixed layer. |
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