Dynamic Variation of Lightning Activity in Southwest China with Topographic Factors under the Background of Climate Change
The southwestern part of China,where lightning disasters have become prominent in re-cent years,is a mountainous area with complex and fragile ecological environment.Lightning activities are closely correlated to topographic factors and vary with changing climate.Based on the WWLLN data in 2005-2017 as well as the DEM data and historical meteorological data,this paper analyzes the rela-tionship between lightning and topographic factor in Southwest China by means of Mann-Kendall trend test and multiple linear regressions,and also explores the variation trend of lightning activity with topographic factor under the situation of climate change.The results show that:(1)The lightning frequency in South-west China presented a significantly increasing trend from 2005 to 2017.In terms of spatial distribution,the lightning frequency was high in the southeast and low in the northwest of the region.(2)During 2005-2017,lightning activities were mainly concentrated in the hilly and low-slope areas with elevation about 400 m above sea level(asl.)and slope of 0° to 5°,decreasing with the rise of elevation.Howev-er,a small peak value appeared in the high mountains and steep slope sections with elevation being 3500-5100 m asl.and slope of 40°.(3)With the warming climate,lightning activity in Southwest China was uplifted and shifted.Under the influence of the increased lowest temperature(growth rate:0.11 ℃·year-1)in the elevation 400-500 m asl.and the increased relative humidity with growth rate of 0.09％·year-1 in the slope of 0°-5°,the proportion of lightning decreased by 0.20％·year-1 and 0.38％·year-1 at elevation of 400-500 m asl.and slope of 0°-5°,respectively.The decreased part was mainly added to the elevation of 3500-5100 m asl.and slope of 10°-25°,respectively.Affected by the increased rela-tive humidity with growth rate 0.15％·year-1 on the slope by east and the increased annual precipitation(9.68 mm·year-1)on the western slope,the proportion of lightning on the eastern and northeastern slopes were reduced by 0.08％·year-1,and the reduced part was mainly transferred to the western slope.
lightningtopographic factorclimate changeSouthwest China
万方数据
维普
