155-166<span style="font-size:11.0pt;font-family:
" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">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,
particularly in tropics, it is important to characterise its 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 southwest monsoon over the period
2006 - 2010 were studied using the ground-based lidar measurements made at the
tropical station, Gadanki (13.5°N, 79.2°E), India. The related meteorological
indicators derived from radiosonde data available with Wyoming Atmospheric Data
Centre were analysed .The results were compared with the data obtained from the
CALIOP on board the CALIPSO satellite. Both the observations show similar
pattern of seasonal variation. In most of the cirrus clouds, the top height
observed was 0.8 km above and below the tropopause and top height was maximum during
monsoon season. The seasonal variation of optical depth showed that most of
cirrus clouds were thin and the optical depth showed highest value during
monsoon period.</span