Research On Observation And Model Simulation Method Of Atmospheric Boundary Layer

The atmospheric boundary layer is the buffer transition layer between the ground and the free atmosphere.It is closely related to people's lives.Determining the height of the top of the atmospheric boundary layer has always been an important topic in boundary layer research.At present,people use a variety of methods to study the evolution of the atmospheric boundary layer feature.Field detection and numerical simulation are two methods that are often used in practical applications.This paper uses conventional meteorological observations,turbulence observations and radiosonde observations in the near-surface layer,as well as lidar remote sensing observations to obtain two-dimensional observation data of the atmospheric boundary layer with typical underlying surface characteristics in Baoding,Hebei and Dachaidan,Qinghai.At the same time,the WRF-YSU model is used to carry out a numerical simulation of the evolution of the atmospheric boundary layer.Combining the field observation results with the numerical simulation results,the physical process in the atmospheric boundary layer is analyzed in detail,and the daily variation characteristics of the atmospheric boundary layer height are obtained.An important factor affecting the development of the atmospheric boundary layer is the heat transfer between the surface and the atmosphere.The calculation methods are varied and different.In this paper,the double-layer difference method and large-aperture scintillator measurement and the empirical relationship between net radiation and flux are used to obtain the sensible heat fluxes of the two ground layers.The calculation results show obvious daily variation characteristics and seasonal differences.Lidar is widely used in atmospheric detection,and can measure the temporal and spatial distribution of temperature,water vapor,aerosol,and trace gas or meteorological elements.The principle of detecting the atmospheric boundary layer is to obtain the time distribution of the extinction coefficient by inverting the backscattered signal.However,since it detects the distribution of matter(herein referred to as aerosol),it should actually be classified as a "material accumulation layer".The inversion results are also more inclined to the material boundary layer rather than the actual atmospheric boundary layer.This method is susceptible to the influence of water vapor molecules and the residual layer,and the layered structure caused by aerosol or other reasons will also affect the judgment of the boundary layer height.In order to better determine the boundary layer changes,this paper uses the WRF-YSU model to carry out numerical simulation,combined with other empirical models,to assist in the analysis of lidar data,and to achieve a more accurate judgment of the boundary layer height.The analysis of the results shows that the Stull thermal growth model,lidar and WRF-YSU model can maintain good consistency during the morning mixed layer development period.The thermal growth model can calculate the height of the boundary layer well during the whole ascent process,and the error with the result of the sounding verification is relatively low.The applicability of the WRF-YSU model is good,but due to the limitation of the model itself,the ultra-high boundary layer cannot be obtained.In addition,it is necessary to make corresponding changes according to the actual situation of various places.