Title: Effects of precipitation on cloud optical thickness derived from combined passive and active space‐borne sensors
Abstract: To obtain a statistical overview of the relationship between precipitation and warm cloud properties in the tropical regions, cloud optical thickness (τ) and the effective radius (re) near the cloud top were retrieved on a global scale by using the Tropical Rainfall Measuring Mission satellite (TRMM). From the retrieved cloud optical thickness and rain rate, optical and microphysical properties of precipitating clouds were examined. Pixels for precipitating were discriminated from those for non‐precipitating by use of the near surface rain rate observed with the Precipitation Radar onboard the TRMM satellite. In particular, we examined how cloud optical thickness changes with precipitation. In general, there were considerable scatter in the relationship between optical thickness and rain rate. The correlations were smeared in data which contain various stages of cloud and precipitation formation/dissipation processes. However, interesting features of the relationship were found: cloud optical thickness is maximum at the effective radius around the value of the critical size below which precipitation hardly forms. For re less than the critical radius, τ increases with re. However, τ begin decreasing at re around the value of the critical radius. Detailed analysis suggests that, dispersion of the size distributions of cloud droplets occurs and has a role to decreases in cloud optical thickness in the conversion process from cloud droplets to rain drops, which results in the tendency to decrease in τ with re.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 2
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