Early warning application of millimeter wave cloud radar in high impact weather
To improve the fine-grained forecasting and early warning level of high-impact weather in cities,this paper utilizes 7 catego-ries of data from the HMB-KPS millimeter-wave cloud radar at Rongcheng meteorological station of Xiong'an,including radar reflectiv-ity factor,radial velocity,etc and surface meteorological observations,as well as weather analysis,radar echo image morphology analy-sis and other methods to analyze the major high-impact weathers in Xiong'an from January 2020 to December 2023,such as torrential rains,strong winds,fog,haze,and sand-dust weathers.The results are as follows:1)The millimeter-wave cloud radar clearly and stereo-scopically detects the structural distribution of cloud systems in high-impact weather including precipitation.In spring,summer and au-tumn,when clouds with echoes intensity equal to or more than 21 dBZ(15 dBZ in winter)and vertical extension height equal to or more than 5 km(2 km in winter)appear,and the lowest cloud base reaches 150 m,it can be considered as the characteristic index of start time of surface precipitation,and the average time advance is about 20 minutes.Conversely,when echo intensity weakens and cloud base height rises,precipitation tends to end.Among all levels of precipitation events,torrential rains have the maximum vertical extensions,liquid water content,etc.2)When the extension height of the echo top reaches more than 8 km and then the height of the cloud top falls rapidly to less than 2 km,the ground is prone to strong winds of more than 8 magnitudes.The echo characteristic of precipitation accom-panied by strong winds is that obvious U or V notch is formed in the strong echo area,and the maximum radial velocity in the notch area is 12.5 m·s-1.3)Cloud radar inversion droplet spectrum data products can better reflect the particle distribution characteristics of precipi-tation with different levels.The Vertically Integrated Liquid Water(VIL)has an early warning significance for precipitation and wind,and the advance is 0-30 min or more.4)For non-precipitation high-impact weather(fog,haze,sand-dust),the millimeter-wave radar echoes are overall weaker,with indistinct transitions between weather phenomena.However,during weather transitions,the radar can rap-idly and clearly detect the precipitation clouds,improving fine-grained forecasting and early warning capabilities of precipitation.
millimeter-wave cloud radartorrential rainstrong windhigh impact weatherforecasting and early warning
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