天津平流雾过程及其空中微物理特征个例研究
投稿时间:2019-05-17  修订日期:2019-05-24  点此下载全文
引用本文:
摘要点击次数: 97
全文下载次数: 0
作者单位E-mail
杨军 南京信息工程大学中国气象局气溶胶与云降水重点开放实验室 jyang@nuist.edu.cn 
高雅 南京信息工程大学中国气象局气溶胶与云降水重点开放实验室  
吴彬贵 天津市气象科学研究所  
董琪如 天津市气象科学研究所  
王兆宇 天津市人工影响天气办公室  
胡汉峰 南京信息工程大学中国气象局气溶胶与云降水重点开放实验室  
基金项目:国家自然科学基金(面上项目)
中文摘要:雾具有一定的厚度和垂直结构,传统雾微物理外场观测试验主要局限于地面,得到的是关于雾层底部的认知。2016/2017冬季在天津开展了平流雾微物理特征观测试验,结合距地66 m高度处雾滴谱和255 m气象塔大气边界层资料,借助突变和趋势一致性非参数检验方法对重度霾后接连发生的两次平流雾过程发展阶段进行客观划分,揭示雾体内部一定高度处雾滴微物理特征和尺度分布特征的观测事实,讨论其生消演变规律。结果表明,伴随西南暖湿平流,饱和层首先在空中出现并向地面扩展,雾过程成熟阶段观测高度范围内升温,雾层处于中性或弱不稳定层结状态。66 m高度处大雾滴持续存在,微物理特征与地面能见度准同步变化,数浓度高值出现在成熟阶段初期,而含水量、特征直径高值出现在成熟阶段后期,对应成熟阶段后期雾滴数浓度减少、地面能见度小幅跃升。消散阶段各尺度数浓度因雾滴蒸发同步减小。
中文关键词:平流雾  微物理特征  尺度谱分布  
 
Advection fog and its microphysical properties: A case study in Tianjin
Abstract:Fog layer has a certain thickness and vertical structural features. Traditional field observations of fog microphysics are usually carried out on the ground, so only the knowledge about the bottom of the fog layer is obtained. In the winter of 2016/2017, a field experiment focused on the microphysical properties of the advection fog was conducted in Tianjin. With the data set of fog droplet spectrum at 66 m height above the ground and the atmospheric boundary layer observation from a 255 m meteorological tower, the life cycle phases of two advection fog events occurring successively after severe haze were objectively differentiated by the use of non-parametric change-point detection and trend tests. The main objective is to reveal the observational characteristics of the microphysics and size distribution of fog droplets at a certain height inside the fog layer, and the relation with fog evolution. The results show that the saturated layer first appeared in the air and expanded to the ground with the southwest warm and moist advection. The temperature increased within the tower height, and the fog layer is under weak unstable or nearly neutral conditions during the mature phases. At 66 m height, large fog droplets had always existed during the fog life cycles and the microphysical parameters changed in quasi-synchronism with the ground visibility. The high concentration of fog droplets appeared at the beginning of the mature phases. The liquid water content and characteristic diameter reached the maximum value before the end of mature phases, but at this time, the concentration of the droplets decreased, and the surface visibility slightly increased. The numbers of droplets with different size decreased synchronously because of fog droplet evaporation in the dissipation phases.
keywords:Advection fog  Microphysical property  Size distribution  Haze
  查看/发表评论  下载PDF阅读器