Empirical relationship between entrainment rate and microphysics in cumulus clouds

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NSTL
Amer Geophysical Union

外文摘要：The relationships between fractional entrainment rate and key microphysical quantities (e.g., liquid water content, droplet number concentration, volume mean radius, and standard deviation of cloud droplet size distributions) in shallow cumuli are empirically examined using in situ aircraft observations from the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign over the Atmospheric Radiation Measurement Southern Great Plains site. The results show that the microphysical quantities examined generally exhibit strong relationships with entrainment rate and that the relationships collectively suggest the dominance of homogeneous entrainment mixing, which is unfavorable to the formation of large droplets and the initiation of warm rain in the clouds. The dominance of the homogeneous mixing mechanism is further substantiated by the dependency on entrainment rate of relationships among various microphysical variables and of cloud droplet size distributions. The dominance of this mechanism is also quantitatively confirmed by examining the degree of homogeneous mixing in the clouds. The dominance of homogeneous mixing may be an important reason why none of the cumulus clouds studied was drizzling.

外文关键词：

cloud microphysicscumulusentrainment mixing mechanismentrainment rateobservation

作者：

Lu, C.、Niu, S.、Liu, Y.、Vogelmann, A.M.

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作者单位：

Key Laboratory of Meteorological Disaster, Ministry of Education, Nanjing University of Information Science and Technology, No. 219, Ningliu Rd., Pukou, Nanjing, Jiangsu 210044, China

Atmospheric Sciences Division, Brookhaven National Laboratory, Upton, NY, United States

出版年：

2013

DOI：

10.1002/grl.50445

Geophysical Research Letters

EISCI

ISSN：0094-8276

年,卷(期)：2013.40(10)

被引量33
参考文献量21