边界层低空急流激光雷达观测及其对PM_(2.5)的影响  

Lidar Observations of Boundary Layer Low-Level Jet and Its Effect on PM_(2.5)

作　　者：傅一原 宋小全[1,2] 廉文超 Fu Yiyuan;Song Xiaoquan;Lian Wenchao(College of Marine Technology,Faculty of Information Science and Engineering,Ocean University of China,Qingdao 266100,Shandong,China;?Laboratory for Regional Oceanography and Numerical Modeling,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,Shandong,China)

机构地区：[1]中国海洋大学信息科学与工程学部海洋技术学院,山东青岛266100 [2]青岛海洋科学与技术试点国家实验室区域海洋动力学与数值模拟功能实验室,山东青岛266237

出　　处：《光学学报》2023年第18期123-133,共11页Acta Optica Sinica

基　　金：国家重点研发计划(2022YFC3700402);国家自然科学基金(61775200)。

摘　　要：大气边界层低空急流是一种重要的边界层物理过程,与污染传输、航空安全、风能开发利用等存在密切联系。相干多普勒测风激光雷达自2020年9月21日至2021年5月8日布设于辽宁葫芦岛市开展风场观测实验,使用激光雷达垂直风场观测资料对该区域大气边界层低空急流展开观测研究,并结合ERA5再分析资料与环境监测站PM_(2.5)质量浓度数据分析。研究时段内,低空急流出现频率为0.11,平均急流风速为13.2m·s^(-1),急流风向主要集中在东北向与西南向,急流高度主要在500m以下,在200~300m频率最高;低空急流风向在冬季与春季存在明显差异,冬季主要集中在东北向,春季主要集中在西南向。分析表明,该区域边界层低空急流的风向主要受到大尺度天气环流背景以及海岸线走势的影响;在沿海区域,海陆热力性质差异引起的温度梯度会根据不同背景风场为急流形成提供有利或不利条件,进而影响不同风向情况下的急流发生频率。夜间边界层低空急流通过增强近地层大气垂直扩散能力,加速PM_(2.5)质量浓度的降低或削弱其增长速度。Objective Low-level jet(LLJ)is a phenomenon where the horizontal wind speed appears to be extreme in the vertical profile.When the extreme value is within the atmospheric boundary layer,it is called boundary layer LLJ.The characteristics of LLJ in the vertical structure make it often appear in the research on heavy convective weather such as heavy rainfall,aviation safety,pollutant transport,and wind energy development and utilization.Main observation instruments for LLJ and vertical wind fields include radiosonde,wind profile radar,and Doppler wind lidar.Doppler lidar can obtain vertical wind field information with a high spatial and temporal resolution.Additionally,its higher vertical resolution and lower detection blind area give itself an obvious advantage in observing the structural features of LLJ.The higher detection accuracy of vertical wind speed enables us to better find the change of atmospheric vertical diffusion ability in the LLJ process,which is also a key mechanism of the impact of LLJ on pollutant concentration.In China,the LLJ research is mainly focused on weather-scale LLJ related to rainfall,while less research is on boundary layer LLJ.Due to the lack of observation data,the studies on structural characteristics of LLJ are rare.Juehua Island,an island about 1o km offshore in the Bohai Sea,has a distinctive LLJ structure due to the influence of land and sea,which makes our study meaningful.Methods The coherent Doppler wind lidar is operated in Juehua Island,Huludao City,Liaoning Province from September 21st,2020 to May 8th,2021.The vertical wind field lidar data is employed to find the atmospheric boundary layer LLJ in this area.Statistical characteristics are analyzed by combining the mean sea level pressure and 1000 hPa temperature data provided by the ERA5 reanalysis model.Combined with the PM_(2.5)mass concentrations of Huludao City,the impact of LLJ on the change in PM_(2.5),mass concentrations is analyzed.In previous studies,the criteria for LLJ are often selected according to the researc

关 键 词：大气光学 多普勒激光雷达 大气边界层 低空急流 PM_(2.5)质量浓度 

分 类 号：P412.25[天文地球—大气科学及气象学] P425.1