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A satellite perspective on cloud water to rain water conversion rates and relationships with environmental conditions
Author(s) -
Sorooshian Armin,
Wang Zhen,
Feingold Graham,
L'Ecuyer Tristan S.
Publication year - 2013
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/jgrd.50523
Subject(s) - environmental science , aerosol , satellite , atmospheric sciences , climatology , precipitation , cloud fraction , radar , ocean color , cloud cover , meteorology , cloud computing , geology , geography , telecommunications , aerospace engineering , computer science , engineering , operating system
A two‐year satellite remote sensing data set from the NASA A‐Train is used to examine conversion rates of cloud water to rain water for warm maritime clouds with different ranges of mean cloud‐layer radar reflectivity and rain rate. Recent work has demonstrated the utility of a novel procedure that relies on the differing sensitivities of passive MODIS measurements and active CloudSat radar measurements to estimate warm cloud conversion rates and associated time scales. That work is extended here to examine regional differences in conversion rates, including sensitivity to environmental parameters such as atmospheric stability and the presence of different aerosol types defined based on values of aerosol optical depth, fine mode fraction, and Ångstrom Exponent. Among eight subregions examined, the tropical Pacific Ocean is characterized by the highest average conversion rate while subtropical stratocumulus cloud regions (far northeastern Pacific Ocean, far southeastern Pacific Ocean, Western Africa coastal region) exhibit the lowest rates. Conversion rates are generally higher at reduced values of lower tropospheric static stability (LTSS). When examining data in two selected ranges for LTSS, higher conversion rates are coincident with higher LWP and factors covarying or rooted in the presence of aerosol types exhibiting lower aerosol index values.