Study of satellite-derived cloud microphysical parameters for tropical cyclones over the North Indian Ocean (2010–2013)

Abstract

A comprehensive study of the cloud microphysics of 18 tropical cyclones (TCs) over the North Indian Ocean was carried out for the period 2010–2013. This was done using MODIS cloud microphysical properties covering tracks of TCs from early development to dissipation. The temporal analysis of cloud optical thickness (COT), cloud effective radius (CER) and cloud phase shows demarcating features during the different stages of TC. The dominance of cumulonimbus clouds, high fraction of precipitating clouds and high percentage of ice clouds during the mature stage of TCs have been demonstrated in light of COT, CER and cloud phase. Thus, CMPs can provide adequate information about the life cycle of TCs. Further, a complete dataset and associated statistics were computed for different stages and spatio-temporal structure of the TC. It has been found that cloud effective radius has mean (standard deviation) of 25.45 (± 3.94) microns during early development, 23.88 (± 5.71) microns and 22.55 (± 4.03) during maturity and dissipation stages respectively. Similarly, the cloud optical thickness has mean (standard deviation) of 15.61 (± 9.77) during early development, 21.87 (± 21.48) and 14.66 (± 10.70) during maturity and dissipation stages respectively. While analyzing the spatial structure, an interesting feature of high cloud effective radius has been observed in the eye region and clouds in this region are found to be of low opacity. These observations corroborate earlier reports on stratocumulus cloud decks observed within a cyclone eye.