The Variety Characteristics Research of the Annual Thunderstorm Days on Leizhou Peninsula during Last 48 Years

There are Zhanjiang, Leizhou, Xuwen, Lianjiang four weather observation stations on the Leizhou Peninsula. By using the wavelet analysis, this article studies the characteristics of the time serial of annual thunderstorm days in the Leizhou Peninsula. The data are from those four stations and covers for the last 48 years from 1960 to 2007. The research revealed the multi-time-scale structure of the annual thunderstorm days. The results show that (1) there is obvious decreasing tendency in the annual thunderstorm days; (2) The average of the annual thunderstorm days of 48 years is 91 d. The value before 1983 is higher than the mean value except in years 1977 and 1980, and is lower than that after 1984 except for 1987 and 1997; (3) There is almost always positive anomaly departure before 1983 and negative after 1984; (4) There are quasi 2 year periodic change in the middle of 60's, remarkable 2-4 year periodic change in the 70's, obvious 3-4 year periodic change in late 80's to late 90's, and remarkable quasi 2 year periodic change from mid to late 90's and the sudden change appears in 1983.