Effect of Robinia pseudoacacia canopy on rainfall characteristics in Xifeng area,Gansu province
QIAO Yonghu;GUO Dongjing;CHEN Xiyun;School of Geographical Sciences,Shanxi Normal University;Library,Shanxi Normal University;Department of Geography,Beijing Normal University;
This study applied the Germany HSC-OTT Persivel32 and traditional rain cylinder to monitor the rainfall characteristics inside and outside of the Robinia pseudoacacia canopy in Xifeng area of Gansu province,and quantitatively analyzed the effects of R. pseudoacacia canopy on the raindrops size,the raindrop speed and the kinetic energy of rainfall. The results show that:( 1) Raindrops diameter outside R. Pseudoacacia forest was mainly concentrated in the range of 0. 31 ~ 1. 06 mm,and the maximum raindrop diameter was 2. 13 mm. The raindrops diameter inside the forest was mainly concentrated in the range of 0. 19 ~ 0. 94 mm,and the maximum raindrop diameter was 1. 38 mm.( 2) The raindrop diameter inside forest was less than outside under the same rainfall intensity. The difference of median diameter of raindrops between inside and outside forest increased with rainfall intensity which finally stable in the range of 0. 4 ~ 0. 6 mm.( 3) Acacia trees reduced the raindrop speed whose diameter range between 1. 38 mm and 2. 38 mm and the decreasing range in 10% ~ 63%.( 4) When rain intensity I 1. 5 mm/h,the rainfall kinetic energy inside R. pseudoacacia trees were larger than outside of it.While,it was opposed when rain intensity I 1. 5 mm/h whose maximum kinetic energy reduction rate was50%.