Analysis of Boundary Layer Structure,Turbulence,and Flux Variations before and after the Passage of a Sea Breeze Front Using Meteorological Tower Data  

作　　者：Ju LI Junxia DOU Donald H. LENSCHOW Mingyu ZHOU Lihong MENG Xiaobin QIU Yubing PAN Jingjiang ZHANG 

机构地区：[1]Institute of Urban Meteorology(Key Laboratory of Urban Meteorology),China Meteorological Administration,Beijing,100089,China [2]State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,China Meteorological Administration,Beijing,100081,China [3]Beijing Research Center for Urban Meteorological Engineering and Technology,Beijing,100081,China [4]National Center for Atmospheric Research,Boulder,CO,80307,USA [5]National Marine Environmental Prediction Center,Beijing,100081,China [6]Tianjin Key Laboratory for Oceanic Meteorology,Tianjin,300074,China [7]Tianjin Institute of Meteorological Science,Tianjin,300074,China

出　　处：《Journal of Meteorological Research》2023年第6期855-877,共23页气象学报（英文版）

基　　金：Supported by the Beijing Natural Science Foundation(8222048);Open Grants of the State Key Laboratory of Severe Weather(2022LASW-A03);Key Innovation Team of China Meteorological Administration(CMA2022ZD09);China Meteorological Administration Innovation Development Project(CXFZ2023J061);Tianjin Meteorology Service Project(202113ybxm05)。

摘　　要：A detailed analysis of a sea breeze front(SBF)that penetrated inland in the Beijing–Tianjin–Hebei urban agglomeration of China was conducted.We focused on the boundary layer structure,turbulence intensity,and fluxes before and after the SBF passed through two meteorological towers in the urban areas of Tianjin and Beijing,respectively.Significant changes in temperature,humidity,winds,CO_(2),and aerosol concentrations were observed as the SBF passed.Differences in these changes at the two towers mainly resulted from their distances from the ocean,boundary layer conditions,and background turbulences.As the SBF approached,a strong updraft appeared in the boundary layer,carrying near-surface aerosols aloft and forming the SBF head.This was followed by a broad downdraft,which destroyed the near-surface inversion layer and temporarily increased the surface air temperature at night.The feeder flow after the thermodynamic front was characterized by low-level jets horizontally,and downdrafts and occasional updrafts vertically.Turbulence increased significantly during the SBF’s passage,causing an increase in the standard deviation of wind components in speed.The increase in turbulence was more pronounced in a stable boundary layer compared to that in a convective boundary layer.The passage of the SBF generated more mechanical turbulences,as indicated by increased friction velocity and turbulent kinetic energy(TKE).The shear term in the TKE budget equation increased more significantly than the buoyancy term.The atmosphere shifted to a forced convective state after the SBF’s passage,with near isotropic turbulences and uniform mixing and diffusion of aerosols.Sensible heat fluxes(latent heat and CO_(2)fluxes)showed positive(negative)peaks after the SBF’s passage,primarily caused by horizontal and vertical transport of heat(water vapor and CO_(2))during its passage.This study enhances understanding of boundary layer changes,turbulences,and fluxes during the passage of SBFs over urban areas.

关 键 词：sea breeze front boundary layer structure TURBULENCE FLUX meteorological tower 

分 类 号：P732[天文地球—海洋科学]