Abstract
The presence of cirrus cloud has its impact on the earth’s radiation budget. In order to study the effect of cirrus clouds in the tropical regions, it is essential to understand and characterize their optical properties. The optical properties of high altitude cirrus clouds are obtained using the polarization diversity ground based Mie lidar instrument at a tropical latitude station in the Indian subcontinent. Lidar measurements are taken for one year (2013) at National Atmospheric Research Laboratory (NARL), located at Gadanki (13.5° North, 79.2° East; 375m AMSL), India and are used for the present investigation. Altitude variations of optical depth and depolarization ratio are discussed. In the altitude range of 10–17 km, the range of the optical depth and depolarization ratio of cirrus cloud was found to be 0.01–0.4 and 0.1–0.4 respectively. The interdependence of optical depth as a function of depolarization ratio is analyzed and a positive correlation is observed (0.3950). From the measured optical depth values, it is categorized that 8%, 77% and 14% of the cirrus clouds are sub-visual, thin and thick clouds. The monthly and seasonal variations of optical properties of cirrus clouds were analyzed. Summary of cirrus cloud layer statistics and the statistical variation (seasonal) of the optical properties of cirrus clouds is presented for the period of study.
Highlights
High altitude cirrus clouds are thin and wispy, mainly composed of ice crystals (Lynch et al, 2002) of dissimilar shape and size
Light Detection And Ranging (Lidar) dataset for the year 2013 (January 2013 to December 2013) was used to study the altitude dependence, distribution, monthly, and seasonal variations of the optical properties of cirrus clouds
In order to analyze the optical properties of cirrus clouds, the annual prominent seasons at this site are categorized as winter (December–January–February), pre–monsoon (March–April– May), monsoon or South–West monsoon (June–July–August), and post–monsoon or North–East monsoon (September– October–November)
Summary
High altitude cirrus clouds (cold clouds) are thin and wispy, mainly composed of ice crystals (Lynch et al, 2002) of dissimilar shape and size. Various studies are done at different seasons to analyze the variations of geometrical and optical properties of cirrus clouds using ground-based lidar over Gadanki region (Krishnakumar et al, 2014; Pandit et al, 2015; Manoj Kumar et al, 2019).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
