Research On Characteristics Of Atmospheric Boundary Layer Detected By Wind Profiler Radar

As a ground-based remote sensing device,wind profile radar can detect real-time meteorological factors such as 3D wind field information,vertical airflow and with high spatial and temporal resolution.There are not many studies on the characteristics of the boundary layer detected by wind profile radar spectrum products.Based on the wind profile radar's ability to continuously,efficiently and accurately detect the atmospheric boundary layer in the absence of precipitation,the wind profile radar and microwave radiometer data are used to apply and improve the traditional methods to retrieve the boundary layer height and results are compared and analyzed under different methods and time-period.The differences of the principles of retrieval are summarized.Various kinds of synchronous wind profile radar data was used to analyze and compare the correlation between the urban and suburban areas of Shanghai boundary layer and wind,and the reasons were pointed out.The traditional gradient method and wavelet method that based on SNR are improved and compared,and the improvement effect is good.The Holzworth method based on the microwave radiometer temperature profile is only suitable for the daytime.The results of temperature gradient method based on the temperature and water vapor density profile vary less diurnally and have a larger minimum daily height,which mainly depends on the selection of the critical value.The principles differences of the above retrieval results were explored.The retrieval based on the SNR was dependent on the humidity gradient;the Holzworth method was highly dependent on the surface temperature;the temperature gradient method was based on the imaginary potential temperature profile.Detection of the urban and suburban areas of Shanghai boundary layer found that the vertical movement of the urban area was stronger than that of the suburban area,which was more obvious at night.Due to the influence of the updraft,the ascending movement of the urban area was stronger.The wind speed is higher in suburbs and at night.The maximum wind speed and its gradients at all heights in suburbs are higher.The wind speed gradient during daytime changes less with height.Above canopy layer,wind speeds and gradients increase rapidly,and once over the rough sublayers,the wind speed changes slowly.Affected by the surface roughness,the wind speed at 100 m in the urban area is significantly lower than that in the suburbs,and above the canopy,the wind speed is closer and the correlation coefficient reaches 73%.Affected by particle size and turbulence,the overall spectral width over the suburbs is stronger,and decreases with increasing height;the turbulent dissipation rate at 400 m in the suburbs during the day is slightly greater,and it is smaller than that in urban areas at night.The boundary layer height of the urban area is generally higher than that of the suburbs during the daytime,especially at noon,reaching 1.4km,while they both decreased significantly at night,maintaining at over 300 m.