气候变化领域集成服务门户(CCPortal): Competing Effects of Droplet Sedimentation and Wind Shear on Entrainment in Stratocumulus

CCPortal

DOI	10.1029/2019MS001617
	Competing Effects of Droplet Sedimentation and Wind Shear on Entrainment in Stratocumulus
	Schulz B.; Mellado J.P.
发表日期	2019
ISSN	19422466
起始页码	1830
结束页码	1846
卷号	11 期号:6
英文摘要	The joint effect of droplet sedimentation and wind shear on cloud top entrainment in stratocumulus is investigated with direct numerical simulations. Although it is well understood that droplet sedimentation weakens entrainment while wind shear enhances entrainment, there is no consensus on the magnitude of each process. We find that the entrainment reduction by droplet sedimentation is sufficiently strong to completely compensate the entrainment enhancement by wind shear, and thus, droplet sedimentation and wind shear effects can be equally important for cloud top entrainment. For instance, for the subtropical conditions considered here, droplet sedimentation weakens entrainment by up to 40% while wind shear enhances entrainment by up to 40%. This result implies that the droplet size distribution can substantially affect cloud lifetimes not only because of its effect on rain formation but also because of its effect on cloud top entrainment, which emphasizes the need for a better characterization of droplet size distributions in stratocumulus. A second implication is that entrainment velocity parametrizations should pay equal attention to droplet sedimentation and to wind shear effects. ©2019. The Authors.
英文关键词	droplet sedimentation; entrainment; evaporative cooling; stratocumulus; turbulence; wind shear
语种	英语
scopus关键词	Air entrainment; Clouds; Drops; Evaporative cooling systems; Sedimentation; Size distribution; Turbulence; Competing effects; Droplet size distributions; Entrainment velocities; Evaporative cooling; Joint effect; Parametrizations; stratocumulus; Wind shears; Shear flow; cloud droplet; entrainment; evaporation; numerical model; sedimentation; size distribution; stratocumulus; turbulence; wind shear; wind velocity
来源期刊	Journal of Advances in Modeling Earth Systems
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/156891
作者单位	Max-Planck-Institut für Meteorologie, Hamburg, Germany
推荐引用方式 GB/T 7714	Schulz B.,Mellado J.P.. Competing Effects of Droplet Sedimentation and Wind Shear on Entrainment in Stratocumulus[J],2019,11(6).
APA	Schulz B.,&Mellado J.P..(2019).Competing Effects of Droplet Sedimentation and Wind Shear on Entrainment in Stratocumulus.Journal of Advances in Modeling Earth Systems,11(6).
MLA	Schulz B.,et al."Competing Effects of Droplet Sedimentation and Wind Shear on Entrainment in Stratocumulus".Journal of Advances in Modeling Earth Systems 11.6(2019).