Optical Properties of Cirrus Clouds in the Tropical Tropopause Region during two Contrasting Seasons

Abstract

Radiation budget of Earth’s atmospheric system is largely impacted by the presence of cirrus clouds. In order to quantify the effect of cirrus clouds, it is important to characterise their vertical structure and optical properties. The variation of the optical and microphysical properties along with the structure and dynamics of the cirrus during two contrasting seasons, the summer and the south west monsoon were studied using ground based lidar measurements made at the tropical station, Gadanki (13.5⁰ N, 79.2⁰ E), India. The related meteorological indicators derived from radiosonde data available with Wyoming atmospheric data centre are analysed .The results are compared with the data obtained from CALIOP on board the CALIPSO satellite. Both the observations follow similar pattern of variation. Most of the cirrus clouds top heights are observed 0.8 km above and below the tropopause and have the maximum top height during monsoon seasons. The seasonal variation of optical depth shows that most of cirrus clouds observed was thin clouds and the optical depth shows highest value during monsoon period.