Cloud-to-ground lightning characteristics in Yunnan province from 2006 to 2010

Cloud-to-ground lightning data have been analyzed for the years 2006-2010 for Yunnan province for all ground flashes, positive flashes, the percentage of positive lightning, and peak currents for negative and positive lightning. Mean 400 thousands cloud-to-ground flashes happen in Yunnan province every year. The highest flash densities are in the Central Yunnan province (6.4 fl· km^-2 yr^-1), Areas of greater than 50% positive lightning occur in the west river valley. The median negative peak current is 27.9kA. The median positive peak current is 47.4 kA. It is founded that substantial differences between wet season lightning (Apr-Sep) and dry season lightning (Oct-Mar). Wet season lightning is characterized by a high CG flash count and percent positive CG flashes less than 5%; dry season lightning is characterized by a low CG flash count and percent positive CG flashes greater than 20%. The most of CG lightning flashes is single return stroke. The CG lightning activity in Yunnan province is weak in the morning and increases rapidly in the afternoon.

I. Introduction

Cloud-to-ground(CG) lightning parameters and the spatial distribution of lightning flashes are of very interest for the design of lightning protection systems, and are of increasing importance for weather forecasting and climatology. The recent deployment of cloud-to-ground (CG) lightning detection networks in different countries have led to the publication of a number of studies of lightning characteristics by many authors during recent years. In this way, a 10-year(1989–1998) summary of lightning ground flash measurements over the contiguous United States has been released by Orville and Huffines [1]. Yair et al. [2] studied the temporal variation of lightning flash density over TelAviv. A 10-year (1986–1995) monthly lightning climatology over Florida has been carried out by Hodanish and Sharp[3]. Lightning flash density, temporal distribution, positive percentage, peak currents and multiplicity have been reported by Orville et al. [4] in the Western Pacific area.