| 1981～2015年华北地区持续霾事件的特征及其环流分类研究 |
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| 引用本文： | 孟亚楠,孙建华,卫捷,赵琳娜.1981～2015年华北地区持续霾事件的特征及其环流分类研究[J].气候与环境研究,2019,24(3):341-358. |
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| 作者姓名： | 孟亚楠 孙建华 卫捷 赵琳娜 |
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| 作者单位： | 1.中国科学院大气物理研究所云降水物理与强风暴实验室,北京 100029;中国科学院大学,北京 1000492.中国科学院大学,北京 1000493.中国科学院大气物理研究所云降水物理与强风暴实验室,北京 1000294.中国气象科学研究院,北京 100081 |
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| 基金项目： | 环境保护部公益性行业科研专项201509001,江西省重点研发计划项目20171BBG70005 |
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| 摘 要： | 根据1981～2015年华北地区地面基本气象要素定时值数据集和地面气候日值数据集站点资料,分别利用14时实测值法和目标区域极端事件的客观识别方法挑选霾日数和持续霾事件,并分析了它们的特征;,然后对持续霾事件进行了分类研究。结果表明:（1）华北地区霾日数空间分布极不均匀,有4个大值区:吕梁山和太行山之间的河谷地区、沿太行山以东的平原、河南北部、环黄海和渤海地区。（2）华北地区共挑选出111个持续霾事件,其中,持续3～5 d的事件最多,占了总数的86.5%,最长的事件可达12 d。（3）持续霾事件和霾日数的空间分布特征相似,且存在明显的年、季变化。1981～2015年持续霾事件数呈增加趋势,冬季增加最显著,其次是秋季和春季,夏季最少。（4）结合地形、霾日数、持续霾事件的分布和环流特征把持续霾事件分为7类,对发生频次较多的4类（华北地区型,河南北部及太行山以东的平原型,河南北部型,河南北部及环渤海、黄海地区型）的环流进行了对比分析。其环流形势的主要特征包括:对流层的中低层华北地区为纬向西风气流或脊前西北气流,我国南部或东南部地区高压西部的西南气流与华北地区的偏西气流产生弱辐合下沉气流;近地面层由于地形的影响形成垂直环流圈,霾最严重的地区一般出现在地形的东坡和垂直环流圈的下沉支。近地面东南气流和低层的西南气流向该地区输送了暖湿空气和污染物。华北地区霾发生位置的不同,主要由低层我国东部或者南部高压的位置和强度,以及局地垂直环流的下沉支的位置决定。这些研究结果可以为华北地区持续性霾的防控提供参考。
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| 关 键 词： | 华北地区 霾日数 持续霾事件 空间分布 环流特征 |
| 收稿时间： | 2018/4/27 0:00:00 |
Characteristics and Circulation Classification of Persistent Haze Events in North China during 1981-2015 |
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| MENG Yanan,SUN Jianhu,WEI Jie,ZHAO Linna.Characteristics and Circulation Classification of Persistent Haze Events in North China during 1981-2015[J].Climatic and Environmental Research,2019,24(3):341-358. |
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| Authors: | MENG Yanan SUN Jianhu WEI Jie ZHAO Linna |
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| Institution: | 1.Key Laboratory of Cloud-Precipitation Physics and Severe Storms, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing 100029;University of Chinese Academy of Sciences, Beijing 1000492.University of Chinese Academy of Sciences, Beijing 1000493.Key Laboratory of Cloud-Precipitation Physics and Severe Storms, Institute of Atmospheric Physics, Chinese Academy of Science, Beijing 1000294.Chinese Academy of Meteorological Sciences, Beijing 100081 |
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| Abstract: | Based on the surface meteorological observational elements and the 1981-2015 climate daily station data from China Meteorological Administration (CMA), 1400 BST (Beijing Summer Time) moment method was used to select haze days (HDs) in North China,and an objective identification technique for regional extreme events was employed to determine persistent haze events (PHEs). Finally, the major characteristics of HDs and PHEs were obtained. The major characteristics of PHEs are as follows: (1) The spatial distribution of HDs in North China was extremely uneven, with four high- frequency regions: The valley area between Lvliang Mountains and Taihang Mountains; the plain east of Taihang Mountains; northern Henan; the gulf area of Bohai and Yellow Seas. (2) A total of 111 PHEs, with the longest one lasting 12 d, were identified. The PHEs lasting three to five days accounted for 86.5%. (3) The annual and seasonal variation of PHEs was very similar to those of HDs. The number of PHEs increased during 1981-2015, which peaked in winter, followed by autumn, spring, and summer. (4) According to the characteristics of topography, HDs, and PHEs and their circulations, PHEs can be categorized into seven types. Among these, we compared the circulations of the four high-frequency PHE types (North China; northern Henan and the plain east of Taihang Mountains; northern Henan; northern Henan and the gulf area of Bohai and Yellow Seas). The major circulation characteristics of the four PHE types were obtained. In the mid-lower troposphere, North China was controlled by zonal westerlies or northwesterlies in the front of ridges. A sinking motion was produced by a weak convergence—formed by southwesterlies along the west of high pressure with westerlies in North China. A vertical circulation existed near the surface, which is related to the influence of topography. The most severe haze areas generally appeared in the east slope of the topography and the subsidence of the vertical circulation. Southeasterlies or southwesterlies in the lower troposphere transported moisture and pollutants into the haze area. The location of haze in North China was mainly determined by the position and intensity of high pressure in the eastern or southern China, as well as the location of the local sinking motion in vertical circulation. These results provide references for the prevention and control of persistent hazes in North China. |
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| Keywords: | North China Haze events Persistent haze events Spatial distribution Circulation characteristics |
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