近31年三穗县暴雨气候特征及成因分析

Climatic Characteristics and Cause Analysis of Rainstorm in Sansui County in Recent 31 Years

利用1986—2016年三穗县地面气象观测站出现暴雨的降水资料,分析暴雨和大暴雨的年际变化和季节分布特征,结合运用小波分析三穗县暴雨强度的周期变化特征,并分析了三穗县暴雨的成因。结果表明,近31年三穗县暴雨总日数为67 d,年平均暴雨总日数为2.23 d;三穗县共出现暴雨日数64 d、大暴雨3 d。近31年三穗县暴雨日数出现了低→高→低→低的波动变化,20世纪90年代暴雨日数出现最多,20世纪80年代和2010年后暴雨日数持平。三穗县暴雨多出现在4—9月,约占总暴雨日数的92.5%,集中出现在5—8月,7月份出现次数最多,暴雨出现最少的为11月;三穗县出现大暴雨次数偏少,其中夏季出现频率较高。三穗县的特殊地理位置和地形特点有利于暴雨天气的形成和发展,影响暴雨天气的主要天气系统为高空槽、低涡、急流、中低空切变、地面冷锋等。

Using the precipitation data of rainstorm in Sangui County ground meteorological observation station from 1986 to 2016,the interannual and seasonal distribution characteristics of rainstorm and heavy rainstorm were analyzed,combined with the use of wavelet analysis to analyze the cyclical characteristics of rainstorm intensity,and analyze the cause of the rainstorm in Sanshui County. The results showed that the total number of rainstorms in Sanshui County in recent 31 years was 67 times,and the annual average number of rainstorms was 2. 23 times. The number of rainstorms was 64 times and the heavy rainstorms was three times. In the past 31 years,the number of rainstorms in Sanshui County appeared low—high—low—low fluctuations. The number of rainstorms in the 1990 s had been the largest,and that had been flat in the 1980 s and after2010. The rainstorm in Sanshui County occurred in April-September,accounting for 92. 5% of the total number of rainstorms,concentrated in May-August,the highest number of occurrences in July,the lowest in November; and the number of heavy rainstorms in Sansui County less than normal,which appeared in the summer higher frequency. The special geographical location and terrain characteristics of Sansui County were favorable to the formation and development of rainstorm. The main weather systems affecting rainstorm were high-altitude trough,low vortex,rapid current,medium-low shear,ground cold front and so on.