摘要
利用无人机搭载气象及环境监测设备于2020年7月29-31日在太原进行飞行试验,对不同高度层颗粒物和气象要素进行观测,得到PM_(2.5)三维分布及其随时间的变化特征,并通过气象要素、天气形势和后向轨迹分析得到污染累积和消散成因以及外地传输作用影响。结果表明:PM_(2.5)浓度的垂直分布差异显著,下午大部分时次满足“下高上低”规律,上午边界层垂直混合和颗粒物吸湿增长可能导致“下低上高”的情况;逆温层对大气垂直混合有明显抑制作用;29日为污染物积累过程,30日和31日白天均为消散过程;副热带高压带来的小风、高湿环境是29日颗粒物逐渐累积的原因,30日槽前对流发展和较大的风速有利于颗粒物浓度下降,31日相对湿度较低、对流发展旺盛使PM_(2.5)浓度快速下降;试验期间气流主要来自东南方向,太原市PM_(2.5)本地积累占主导地位,外地传输更多来自于本省晋中、长治等邻近城市。
A small remote⁃controlled Unmanned Aerial Vehicle(UAV)carrying meteorological and environmental monitoring equipment was used to observe the PM_(2.5) concentration,temperature,relative humidity and other elements at different altitude levels in Taiyuan from July 29 to 31,2020.According to the flight experiment results,the three⁃dimensional distribution of PM_(2.5) and its variation characteristics over time were obtained.The causes of pollution accumulation and dissipation,the influence of external transport were analyzed through the vertical distribution of PM_(2.5) concentration and meteorological elements,the weather situation and backward trajectory analysis.Results show that compared with the horizontal distribution difference,the vertical distribution difference of PM_(2.5) concentration is more significant.Most of the time,PM_(2.5) concentration meets the rule of“higher⁃bottom and lower⁃top”,and the hygroscopic growth of particulate matter may lead to the situation of“lower⁃bottom and higher⁃top”.The relative humidity generally increases with the increase of height,but the temperature varies in the opposite way;the inversion layer inhibits the vertical mixing of atmosphere obviously.On 29,there was a process of pollutant accumulation.On 30 and 31,there was a process of pollutant dissipation in the daytime and an accumulation process in the night.The warm and wet airflow brought by the subtropical high and the weak wind near the ground were the reasons for the gradual accumulation of particulate matter on 29.On 30,the relative humidity dropped rapidly,and the wind speed was relatively high,which was conducive to the decrease of the concentration of particulate matter.On 31,the ground relative humidity was the lowest,and the strong development of upper and lower convection led to the rapid decrease of the PM_(2.5) concentration.During the three days,the air flow mainly came from the southeast direction.The local accumulation of PM_(2.5) in Taiyuan was dominant,while the non⁃local transmission was mainly from neighboring cities such as Jinzhong and Changzhi in the province.
作者
汪文雅
郭伟
王雁
陈玲
王淑敏
成鹏伟
WANG Wenya;GUO Wei;WANG Yan;CHEN Ling;WANG Shumin;CHENG Pengwei(Shanxi Institute of Meteorological Sciences,Taiyuan 030002,China)
出处
《气象科学》
北大核心
2021年第4期526-534,共9页
Journal of the Meteorological Sciences
基金
山西省面上青年基金资助项目(201801D221333)
山西省面上自然科学基金资助项目(201901D111465)
秦岭和黄土高原生态环境气象重点实验室开放研究基金资助课题(2020G-24)。
作者简介
通信作者:王雁(WANG Yan).qkswy@126.com。
