Characteristics and Early Warning Protection of Lightning Activity Along China-Laos Railway

In order to provide a scientific basis for the lightning protection project of the China-Laos Railway, the spatio-temporal distribution characteristics of lightning activity along the China-Laos Railway are analyzed using the lightning data monitored by the Lightning probe (LIS) on TRMM satellite from 1998 to 2013. The results show that: (1) The average flash density along the railway is 10.8 $\mathrm{f}1\cdot \text{km}^{-2}\cdot \text{yr}^{-1}$ , and the flash density gradually increases from north to south. The minimum flash density is 2.1 fl· $\text{km}^{-2}\bullet\text{yr}^{-1}$ (Moding Station), and the most active lightning activity is Vientiane Station, and the maximum lightning activity is 35.2 $\text{fl}$ · km ${}^{-2} {\text{yr}^{-1}}$ . (2) Lightning activity along the railway has significant seasonal and daily changes. Lightning activity in spring and summer was significantly higher than that in autumn and winter, and there was no significant seasonal difference along the Lao section. The peak of lightning activity along the China-Laos railway occurred in April, with only some sections in July or August. Lightning is likely to occur in most areas along the route from 16:00 to 20:00 local time. (3)The lightning activity along the China-Laos Railway is obviously affected by altitude and latitude. Lightning density was inversely correlated with altitude and latitude, and the correlation coefficients were $-0.67$ and $-0.73$ , respectively. With increasing altitude and latitude, the proportion of lightning occurring between 12:00 and 20:00 increases.(4) $\text{The}$ expression of fitting cumulative probability distribution curve of lightning current amplitude along the China-Laos Railway in Yunnan section is $\mathrm{P}=1/(1+(\mathrm{I}/29.0)^{3.0})$ .