利用风廓线分析影响中山降水的低空急流特征

利用中山市风廓线资料,对2019年4-6月(前汛期)的对低空急流特征以及与降水关系进行分析,结果表明:(1)低空急流(3 km以下)的强度与面雨量、单站最大日雨量之间存在正相关性,其中4、6月相关性较好,低空急流风速较大,中山的降雨量相应较大,5月相关性不显著;大雨量级对应的低空急流平均风速值最大,无雨情况对应的平均风...

Analysis of the Characteristics of Low-level Jet Streams Affecting the Precipitation in Zhongshan Using Wind Profilers

Using the data of a wind profiler in Zhongshan,this work studies the characteristics of a low-level(below 3 km)jet stream(hereafter referred to as"LLJS")and its relationship with precipitation in the April-June raining season of 2019.The result is shown as follows.(1)The intensity of the LLJS is positively correlated with both areal rain amount and maximum diurnal rain amount for a single observation station.The correlation is better in April and June than in May,and large wind speeds of the LLJS are corresponding with large rain amounts in the city.Mean wind speed of the LLJS is the maximum when the rain is at a high intensity level but it is the minimum when there is no rain.(2)The altitude of the LLJS is mainly above 2.0 km,taking up 55.0% of the total.The LLJS lasting between 4 and 6 h and starting between 08:00 and 14:00 occurs for the largest number of days.(3)For the two cases of heavy rain analyzed,the observation product of the Zhongshan wind profiler is well corresponding with the intensity and duration of precipitation.Vertical shear is found in the horizontal wind and the larger the radial velocity and the width of speed spectrum,the larger the rain intensity.As the maximum width of speed spectrum and maximum signal-noise ratio occur 1 h earlier than the intense rain,they are somewhat helpful in nowcasting and pre-warning.