气候变化领域集成服务门户(CCPortal): Quantifying vertical wind shear effects in shallow cumulus clouds over Amazonia

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DOI	10.5194/acp-22-11867-2022
	Quantifying vertical wind shear effects in shallow cumulus clouds over Amazonia
	Cecchini, Micael Amore; de Bruine, Marco; de Arellano, Jordi Vila-Guerau; Artaxo, Paulo
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	11867
结束页码	11888
卷号	22 期号:17 页码:22
英文摘要	This study analyses and quantifies the effects of vertical wind shear (VWS) on the properties of shallow cumulus cloud fields over Central Amazonia. We perform idealised simulations with high resolution (50 m horizontally and 20 m vertically) using the Dutch Atmospheric Large-Eddy Simulation (DALES) model, changing the initial conditions and large-scale forcing of VWS. The resulting cloud field is analysed by applying a cloud tracking algorithm to generate Lagrangian datasets of the life cycle of individual clouds as well as their time-varying core and margin dimensions. The reference run has no wind speed or directional shear and represents a typical day in the local dry season. Numerical experiments with moderate and high wind speed shear are simulated by adding linear increases in the wind speed of 1.2 and 2.4 m s(-1) k m(-1), respectively. Three additional runs are made by adding 90 degrees of wind rotation between the surface and the top of the domain (5 km) on top of the three wind speed shear conditions. We find that clouds developing in a sheared environment have horizontal equivalent diameter increased by up to 100m on average, but the cloud depth is reduced. Our quantification shows that VWS tends to increase the size of the cloud cores but reduces their relative area, volume, and mass fractions compared to the overall cloud dimensions. The addition of 2.4 m s(-1) k m(-1) of VWS decreases the relative core area by about 0.03 (about 10% of the overall average) and its volume and mass ratios by about 0.05 (10 %-25% in relative terms). Relevant for the cloud transport properties is that the updraught speed and the liquid water content are lower within the cores, and consequently so is the upward mass flux. All quantifications of mean cloud properties point to the inhibition of convective strength by VWS, therefore hampering the shallow-to-deep transition. However, open questions still remain given that the individually deepest clouds were simulated under high environmental shear, even though they occur in small numbers. This could indicate other indirect effects of VWS that have opposite effects on cloud development if found to be significant in the future.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000853513100001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273548
作者单位	Universidade de Sao Paulo; Utrecht University; Wageningen University & Research; Max Planck Society; Colorado State University; Universidade de Sao Paulo
推荐引用方式 GB/T 7714	Cecchini, Micael Amore,de Bruine, Marco,de Arellano, Jordi Vila-Guerau,et al. Quantifying vertical wind shear effects in shallow cumulus clouds over Amazonia[J],2022,22(17):22.
APA	Cecchini, Micael Amore,de Bruine, Marco,de Arellano, Jordi Vila-Guerau,&Artaxo, Paulo.(2022).Quantifying vertical wind shear effects in shallow cumulus clouds over Amazonia.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(17),22.
MLA	Cecchini, Micael Amore,et al."Quantifying vertical wind shear effects in shallow cumulus clouds over Amazonia".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.17(2022):22.