摘要
基于波长扫描光腔衰荡光谱线监测系统在海螺沟国家大气背景站(以下简称海螺沟站)开展甲烷(CH_(4))连续自动监测,通过局部近似回归法进行背景值筛分分析。结果表明:2016、2017年海螺沟站CH_(4)年均体积分数和筛分的背景体积分数接近,两者浓度水平与北半球中纬度地区全球本底站CH_(4)浓度水平相当;海螺沟站CH_(4)能够代表背景区域浓度水平。海螺沟站CH_(4)体积分数呈春、夏季低,秋、冬季高特征,季节变化主要受到特定的地理环境和大气环流的影响,大气环流占主导影响。夏季CH_(4)体积分数最低但日振幅最大,与高原高海拔背景下森林地带的辐射对流引起局地扩散作用有关。采用逐步逼近回归筛分CH_(4)监测数据,海螺沟站CH_(4)背景季浓度变化和北半球中高纬度地区其他背景站大气CH_(4)的季节变化特征以及CH_(4)季体积分数振幅基本一致。背景站四季的CH_(4)载荷贡献在16个风向分布结果表明,在春、夏季存在西风带下南亚方向污染物气团的远距离输送;青藏高原东部近地面在冬季处于反气旋冷高压控制下,而SSW方向风向能够短暂打破这种稳定的气象条件,污染物得到迅速扩散,SSW为负贡献。
The atmospheric CH_(4)were continuously monitored in the national atmospheric background station of Hailuogou based on optical cavity ring-down spectroscopy method,and the background value was screened through the local approximation regression method.The results showed that the annual average volume fraction of CH_(4)was close to screening background volume fraction of Hailuogou in 2016 and 2017,and their concentrations were comparable to those of the global background stations in the mid-latitudes of the northern hemisphere.The CH_(4)concentration in Hailuogou station was characterized by low concentration in spring,summer and high concentration in autumn and winter.Seasonal changes were mainly influenced by specific geographical environment and atmospheric circulation,which is the dominant influence.In summer,the CH_(4)volume fraction was the lowest but the daily amplitude was the largest,which was related to the local diffusion caused by radiation convection in forest area under the background of high altitude of plateau.The observation data of CH_(4)by step approximation regression screening showed that the seasonal variation of CH_(4)background concentration in Hailuogou station was basically consistent with the seasonal variation characteristics of atmospheric CH_(4)and the seasonal concentration amplitude of CH_(4)in other background stations in the middle and high latitudes of the northern hemisphere.The distribution of the background station CH_(4)load contribution in 16 wind directions in four seasons showed that in spring and summer,there was long distance transport of pollutant air masses in South Asia under westerly belt.Under the control of near-surface anticyclone cold high pressure in the east of Qinghai-Tibet Plateau in winter,the SSW direction of the wind could temporarily break the stable meteorological conditions,the pollutants got rapid diffusion,SSW was a negative contribution belt.
作者
廖乾邑
陈建文
杜丽
LIAO Qianyi;CHEN Jianwen;DU Li(Sichuan Ecological and Environmental Monitoring Center,Chengdu 610000,China;State Environmental Protection Key Laboratory of Quality Control in Environmental Monitoring,China National Environmental Monitoring Centre,Beijing 100012,China)
出处
《中国环境监测》
CAS
CSCD
北大核心
2021年第2期68-75,共8页
Environmental Monitoring in China
关键词
青藏高原
高寒森林
甲烷
背景浓度
地面风
Qinghai-Tibet Plateau
Alpine forest
methane
background concentration
surface wind
