Abstract:

Based on the data from a cloud-ground lightning location system and 24 hours precipitation data from the weather stations, the characteristics of lightning in Shaoyang region from 2008 to 2010 were analyzed and its relationship with precipitation was discussed. The results show that most lightning is negative and its large value center is located in the northeast, while its frequency decreases from northeast to southwest. The frequency of cloud-to-ground (CG) lightning has an obvious diurnal change, and the highest frequency usually occurs from 13:00 to 19:00. The cases under 1 mm and 10 mm accumulated precipitation account for 29.63 % and 76.30 % respectively with lightning, while corresponding values are 69.44 % and 96.30 % without lightning. The rainfall events that 24 hours accumulated precipitation is over 20 mm usually occur with lightning, and it is seldom without lightning. The correlation coefficients between CG lightning frequency and convective rainfall are greater than that between CG lightning frequency and the total precipitation, and the former becomes stronger with the increasing of the time-scale.

Key words: Negative cloud-ground lightning, Cloud-ground lightning frequency, Cloud-ground lightning density