Characteristics of Various Wind Profile Radar Products in Snowfall and Freezing Rain in Guizhou
Based on the data of CFL-03 atmospheric boundary layer wind profiler radar and the automatic weather observation data of Guiyang Airport from January 2019 to June 2022,this paper verifies the availability of WPR data and analyses horizontal wind field,vertical wind speed,echo intensity,atmospheric refractive index structure constant and other physical quantities in detail according to the typical snowfall and freezing rain process;at the same time,the differences of WPR data between different intensity snowfalls and freezing rains are compared.Finally,the WPR data of snowfall and freezing rain in recent three years are statistically analysed.The results show that:(1)The horizontal wind field of WPR reflects that the thickness and intensity of cold air during snowfall exceed that freezing rain,the middle and lower layers are controlled by cold advection during snowfall,while they are warm advection during freezing rain.(2)The greater the central value of Cn,the higher the upward development height of the large value area,and the stronger the snowfall intensity;and the increase/decrease of high-level C2n is ahead of the increase/decrease of snowfall,which can reflect the intensity change of snowfall.(3)The radar reflectivity of snowfall leans to the left in the vertical direction,so the change of radar reflectivity in high-level layers is an indicative of the change of snowfall intensity,the radar reflectivity of freezing rain presents a"strong-weak-strong"distribution in the vertical direction,which is consistent with the"cold-warm-cold"stratification distribution of temperature field in the vertical direction.(4)In freezing rain,the falling speed of particles is slower than that of snowfall,and the precipitation particles almost only fall in the cold air area below 1500 m with the speed of 0.2 to 1.0 m/s;while in sleet,the falling speed is faster than that of pure snow,and the falling speed of light snow is the slowest.