Role of vertical structure of cloud microphysical properties on cloud radiative forcing over the Asian monsoon region
Five years (2006–2010) of clouds and earth’s radiant energy system (CERES) and CloudSat data have been analyzed to examine the role of vertical structure of cloud microphysical properties on cloud radiative forcing (CRF) parameters at the top-of-the atmosphere over the Asian monsoon region during the summer monsoon season (June–September) and the Pacific warm pool region during April. Vertical profile of cloud properties (optical depth, cloud liquid water content and cloud ice water content) derived from CloudSat data has been used for the present analysis. Shortwave, longwave and net CRF derived from the CERES data have been used. The results suggest an imbalance between shortwave cloud radiative forcing and longwave cloud radiative forcing over the Asian monsoon region consistent with the results reported earlier. The present analysis suggests that over the Bay-of-Bengal (BoB), vertical profile of cloud microphysical properties determine more than 50 % of variance in CRF. However, over the Pacific warm pool region, cloud microphysical property profiles does not contribute significantly to variance in net CRF (<10 %). Over the BoB, large asymmetry between shortwave and longwave CRF is caused by large amounts of cloud liquid water content in the layer between the surface and 9 km. The present study highlights the importance of accurate representation of cloud microphysical properties in determining the influence of clouds on the radiative balance over the top-of-the atmosphere.
KeywordsCloud radiative forcing Cloud microphysics Radiative budget Cloud vertical structure Indian summer monsoon Pacific warm pool region
We would like to express our gratitude to the NASA CloudSat project and CloudSat data processing center (CDPC) for providing huge CloudSat dataset on disks in response to our data order. Thanks are also to NASA Langley science directorate and the staff of all CERES teams responsible for production and free distribution of the CERES data sets used in the study. We thank director NARL for providing necessary facilities to carry out the research activity. Also the authors are grateful to both the reviewers for their positive and constructive comments, which helped us to improve the quality of the paper.
- Kau WS, Wu CH, Tsou CH (2003) The cloud radiative forcing over Asian-Pacific summer monsoon region. Terr Atmos Ocean Sci 14:445–467Google Scholar
- Norm Wood (2008) Level 2B radar-visible optical depth cloud water content (2B-CWC-RVOD) process description document. http://www.cloudsat.cira.colostate.edu/dataSpecs.php?prodid=76. Last modified 23 October 2008
- Pai DS, Rajeevan M (1998) Clouds and cloud radiative forcing over tropical Indian Ocean and their relationship with sea surface temperature. Curr Sci 75:373–381Google Scholar
- Smith GL, Bruce A, Wielicki Bruce R, Barkstrom Robert B, Lee Kory J, Priestley Thomas P, Charlock Patrick Minnis, Kratz David P, Loeb Norman, Young David F (2004) Clouds and Earth radiant energy system: an overview. Adv Space Res 33:1125–1131. doi: 10.1016/S0273-1177(03)00739-7 CrossRefGoogle Scholar
- Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL (eds) (2007) Contributions of working group I to the fourth assessment report of intergovernmental panel on climate change, chapter 8. Cambridge University Press, Cambridge, UK, New York, USA, p 996Google Scholar