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Long-term trend analysis and climatology of tropical cirrus clouds using 16 years of lidar data set over Southern India.
- Source :
- Atmospheric Chemistry & Physics; 2015, Vol. 15 Issue 24, p13833-13848, 16p, 3 Charts, 10 Graphs, 1 Map
- Publication Year :
- 2015
-
Abstract
- Sixteen-year (1998-2013) climatology of cirrus clouds and their macrophysical (base height, top height and geometrical thickness) and optical properties (cloud optical thickness) observed using a ground-based lidar over Gadanki (13.5° N, 79.2° E), India, is presented. The climatology obtained from the ground-based lidar is compared with the climatology obtained from 7 and a half years (June 2006-December 2013) of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations. A very good agreement is found between the two climatologies in spite of their opposite viewing geometries and the differences in sampling frequencies. Nearly 50-55% of cirrus clouds were found to possess geometrical thickness less than 2 km. Ground-based lidar is found to detect a higher number of sub-visible clouds than CALIOP which has implications for global warming studies as sub-visible cirrus clouds have significant positive radiative forcing. Cirrus clouds with mid-cloud temperatures between -50 to -70 °C have a mean geometrical thickness greater than 2 km in contrast to the earlier reported value of 1.7 km. Trend analyses reveal a statistically significant increase in the altitude of sub-visible cirrus clouds which is consistent with the recent climate model simulations. The mid-cloud altitude of sub-visible cirrus clouds is found to be increasing at the rate of 41±21myear<superscript>-1</superscript>. Statistically significant decrease in optical thickness of sub-visible and thick cirrus clouds is observed. Also, the fraction of sub-visible cirrus cloud is found to have increased by 9% in the last 16 years (1998 to 2013). This increase is mainly compensated by a 7% decrease in thin cirrus cloud fraction. This has implications for the temperature and water vapour budget in the tropical tropopause layer. [ABSTRACT FROM AUTHOR]
- Subjects :
- CLIMATOLOGY
ATMOSPHERIC sciences
CLIMATE change
GREENHOUSE gases
GLOBAL warming
Subjects
Details
- Language :
- English
- ISSN :
- 16807316
- Volume :
- 15
- Issue :
- 24
- Database :
- Complementary Index
- Journal :
- Atmospheric Chemistry & Physics
- Publication Type :
- Academic Journal
- Accession number :
- 112381903
- Full Text :
- https://doi.org/10.5194/acp-15-13833-2015