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contributor authorHe, Q. S.
contributor authorLi, C. C.
contributor authorMa, J. Z.
contributor authorWang, H. Q.
contributor authorShi, G. M.
contributor authorLiang, Z. R.
contributor authorLuan, Q.
contributor authorGeng, F. H.
contributor authorZhou, X. W.
date accessioned2017-06-09T16:55:26Z
date available2017-06-09T16:55:26Z
date copyright2013/03/01
date issued2012
identifier issn0022-4928
identifier otherams-76545.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4219004
description abstracts part of the Tibet Ozone, Aerosol and Radiation (TOAR) project, a micropulse lidar was operated in Naqu (31.5°N, 92.1°E; 4508 m MSL) on the Tibetan Plateau to observe cirrus clouds continuously from 19 July to 26 August 2011. During the experiment, the time coverage of ice clouds only was 15% in the upper troposphere (above 9.5 km MSL). The cirrus top/bottom altitudes (mean values of 15.6/14.7 km) are comparable to those measured previously at tropical sites but relatively higher than those measured at midlatitude sites. The majority of the cloud layers yielded a lidar ratio between 10 and 40 sr, with a mean value of 28 ± 15 sr, characterized by a bimodal frequency distribution. Subvisible, thin, and opaque cirrus formation was observed in 16%, 34%, and 50% of all cirrus cases, respectively. A mean cirrus optical depth of 0.33 was observed over the Tibetan Plateau, slightly higher than those in the subtropics and tropics. With decreasing temperature, the lidar ratio increased slightly, whereas the mean extinction coefficient decreased significantly. The occurrence of clouds is highly correlated with the outgoing longwave radiation and the strong cold perturbations in the upper troposphere. Deep convective activity and Rossby waves are important dynamical processes that control cirrus variations over the Tibetan Plateau, where both anvil cirrus outflowing from convective cumulonimbus clouds and large-scale strong cold perturbations in the upper troposphere should play an important role in cirrus formation.
publisherAmerican Meteorological Society
titleThe Properties and Formation of Cirrus Clouds over the Tibetan Plateau Based on Summertime Lidar Measurements
typeJournal Paper
journal volume70
journal issue3
journal titleJournal of the Atmospheric Sciences
identifier doi10.1175/JAS-D-12-0171.1
journal fristpage901
journal lastpage915
treeJournal of the Atmospheric Sciences:;2012:;Volume( 070 ):;issue: 003
contenttypeFulltext


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