纯转动拉曼激光雷达探测北京地区近地面大气温度

发布时间：2018-11-24 07:56

【摘要】：对流层大气温度的垂直分布特征直接关联天气现象和大气污染物扩散,一直是气象和环境部门的重点观测对象。当前激光雷达技术已经成为探测对流层大气温度垂直分布和时间演变的有效手段。然而由于对流层中含有大量的气溶胶粒子,因此利用传统的振动拉曼和瑞利散射激光雷达技术测量大气温度具有一定的局限性,尤其是边界层内存在高浓度的气溶胶粒子会严重降低大气温度测量精度。采用纯转动拉曼激光雷达技术可有效降低气溶胶粒子对测量温度精度的影响。纯转动拉曼测温激光雷达的核心是分光单元设计,国内外研究普遍使用基于双光栅干涉仪的分光方法。文中将采用基于滤光片法的纯转动拉曼信号分光设计,相比而言该方法具有更高的分光效率,并且能够通过调节滤光片的角度改变激光雷达系统的灵敏度,操作更为简单。在中国科学院"大气灰霾追因与控制"先导专项支持下,该激光雷达与2014年11月安置在中国科学技术大学超级大气观测站。在亚太经济合作组织北京会议期间,展开大气环境测量试验。激光紫外波段能量约为200 m J,频率为20 Hz,激光脉冲数为5 000发,空间分辨率为7.5 m。实验结果表明,在晴朗无云气溶胶浓度较小的天气条件下温度测量统计误差小于1.5 K,测量高度可达10 km,在7.5 km以下统计误差小于1 K;在有薄云或者轻度雾霾天气条件下,温度测量统计误差在±3K左右,测量有效高度通常在6~8 km,在4.8 km以下统计误差小于1 K。
[Abstract]:The vertical distribution of temperature in the troposphere is directly related to weather phenomena and atmospheric pollutant diffusion, and has been a key observation object in meteorological and environmental departments. At present, lidar technology has become an effective means to detect the vertical distribution and time evolution of atmospheric temperature in the troposphere. However, because there are a lot of aerosol particles in the troposphere, the traditional vibratory Raman and Rayleigh scattering lidar techniques have some limitations in measuring atmospheric temperature. In particular, the presence of high concentrations of aerosol particles in the boundary layer will seriously reduce the accuracy of atmospheric temperature measurement. The pure rotational Raman lidar technique can effectively reduce the influence of aerosol particles on the measurement temperature accuracy. The core of pure rotational Raman temperature measuring lidar is the design of light splitting unit, which is widely used in domestic and foreign research based on double grating interferometer. In this paper, the pure rotational Raman signal based on filter method is designed. Compared with this method, the method is more efficient, and the sensitivity of lidar system can be changed by adjusting the angle of filter, and the operation is simpler. The lidar was installed at the Super Atmospheric Observatory of the University of Science and Technology of China in November 2014 with the support of the pilot project "Air Haze recovery and Control" of the Chinese Academy of Sciences. During the Asia-Pacific Economic Cooperation (APEC) Beijing meeting, an atmospheric environmental measurement test was launched. The energy of ultraviolet band is about 200mJ, the frequency is 20 Hz, the number of laser pulses is 5 000, and the spatial resolution is 7.5 m. The experimental results show that the statistical error of temperature measurement is less than 1. 5 K and the height of measurement can reach 10 km, under 7.5 km under the condition of clear and cloudless aerosol concentration smaller than 1. 5 K. Under the condition of thin cloud or mild haze weather, the statistical error of temperature measurement is about 卤3K, and the effective height of measurement is usually less than 1 KK when the effective height is 6 ~ 8 km, or less than 4.8 km.
【作者单位】：中国科学院合肥物质科学研究院安徽光学精密机械研究所大气成分与光学重点实验室;中国科学技术大学;
【基金】：国家863计划(2012AA120901) 国家自然科学基金(41405032) 中国科学院重点部署项目(KJZD-EW-TZ-G06-01-20) 安徽省自主创新专项(12Z0104074)
【分类号】：TN958.98

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