Optical and geometrical properties of cirrus clouds from lidar measurements above Hanoi, Vietnam

Abstract

We report the results of our long-term monitoring study of cirrus clouds using our locally developed lidar sytem located in Hanoi, Vietnam (21.03°N, 105.85°E). Our data, spanning the period from 2011 to 2017, show that the cirrus clouds above Hanoi are generally found between 6.7 and 18.0 km with a mean height of 14.0 km. The cloud thickness is estimated to vary between 0.2 and 7.0 km with an average thickness of 2.3 ± 1.2 km. We also derive an average optical depth of 0.32 ± 0.22 and an average lidar ratio 30 ± 18. We also compare the geometrical and optical properties of cirrus clouds above Hanoi, where until now lidar study is still lacking, with that obtained for other locations in Asia and around the world.