DOI: 10.1002/2016MS000731
Scopus记录号: 2-s2.0-85011556535
论文题名: Cloud-edge mixing: Direct numerical simulation and observations in Indian Monsoon clouds
作者: Kumar B ; , Bera S ; , Prabha T ; V ; , Grabowski W ; W
刊名: Journal of Advances in Modeling Earth Systems
ISSN: 19422466
出版年: 2017
卷: 9, 期: 1 起始页码: 332
结束页码: 353
语种: 英语
英文关键词: Air
; Air entrainment
; Atmospheric thermodynamics
; Chemical activation
; Direct numerical simulation
; Drops
; Evaporation
; Fighter aircraft
; Mixing
; Numerical models
; Size distribution
; Turbulence
; Droplet concentration
; Droplet size distributions
; Indian subcontinents
; Microphysical property
; Precipitation enhancement
; Small scale turbulence
; Spatial and temporal scale
; Thermodynamic conditions
; Precipitation (meteorology)
; aerosol
; cloud condensation nucleus
; convective cloud
; diagram
; droplet
; entrainment
; evaporation
; mathematical analysis
; moisture
; monsoon
; observational method
; precipitation (chemistry)
; size distribution
; spatial variation
; temperature
; thermodynamics
; turbulent mixing
; vertical movement
; India
英文摘要: A direct numerical simulation (DNS) with the decaying turbulence setup has been carried out to study cloud-edge mixing and its impact on the droplet size distribution (DSD) applying thermodynamic conditions observed in monsoon convective clouds over Indian subcontinent during the Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX). Evaporation at the cloud-edges initiates mixing at small scale and gradually introduces larger-scale fluctuations of the temperature, moisture, and vertical velocity due to droplet evaporation. Our focus is on early evolution of simulated fields that show intriguing similarities to the CAIPEEX cloud observations. A strong dilution at the cloud edge, accompanied by significant spatial variations of the droplet concentration, mean radius, and spectral width, are found in both the DNS and in observations. In DNS, fluctuations of the mean radius and spectral width come from the impact of small-scale turbulence on the motion and evaporation of inertial droplets. These fluctuations decrease with the increase of the volume over which DNS data are averaged, as one might expect. In cloud observations, these fluctuations also come from other processes, such as entrainment/mixing below the observation level, secondary CCN activation, or variations of CCN activation at the cloud base. Despite large differences in the spatial and temporal scales, the mixing diagram often used in entrainment/mixing studies with aircraft data is remarkably similar for both DNS and cloud observations. We argue that the similarity questions applicability of heuristic ideas based on mixing between two air parcels (that the mixing diagram is designed to properly represent) to the evolution of microphysical properties during turbulent mixing between a cloud and its environment. © 2017. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75826
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: High Performance Computing Systems, Indian Institute of Tropical Meteorology, Pune, India; Physics and Dynamics of Tropical Cloud, Indian Institute of Tropical Meteorology, Pune, India; Mesoscale and Microscale Meteorology Laboratory, National Center for Atmospheric Research, Boulder, CO, United States
Recommended Citation:
Kumar B,, Bera S,, Prabha T,et al. Cloud-edge mixing: Direct numerical simulation and observations in Indian Monsoon clouds[J]. Journal of Advances in Modeling Earth Systems,2017-01-01,9(1)