Abstract:By using the long series observational data of thunderstorms in Changzhou from 1952 to 2007 and Doppler radar data, the variation, periodic char acteristics and echo characters of thunderstorms are studied by means of mathema t ical statistics and the wavelet analysis. The results show that the interdec adal thunder storm variability is great, and the annual number of thunderstorm day has a decr easing tr end. The interannual variation in thunderstorm day number is comparatively larg e with the maxi mum being 5.9 times the minimum. The obvious seasonal variation of thunderstorms can also be detected, and the period of April to Sep tember is more frequent months for th understorms and their occurrence in July and August is the most, and over 66.8% thunder storms occur in summer season. From the diurnal distribution, the highest number i s in the evening, followed by the afternoon, at least in the morning. The result s from wav elet analysis show that the annual number of thunderstorm days in Chan gzh ou has a period of about 12 years within nearly 56 years and there is a perio d of about 7 y ears from 1952 to 2004.In addition, there is still three to four years of small cycle charact eristics from 1968 to 2007. It is found that the radar basic reflectivity of thu nderstor ms in Changzhou is from 30 to 65dBz and the echo top high is between 6 to 17km and the thunderstorm radar echoes are in five major shifts: the southwest to nor the ast, the southeast to northwest, the northwest to southeast, the rotation, and the local gen eration.The strong wind and hail storm in Changzhou are analyzed using statistic al analysis methods. It is found that the thunderstorm winds occurring in July ran k on top and the hail occurs the most in May and July.