DOI: 10.1016/j.atmosres.2019.03.009
Scopus记录号: 2-s2.0-85062593262
论文题名: Characteristics of roll and cellular convection in a deep and wide semiarid valley: A large-eddy simulation study
作者: Babić N. ; De Wekker S.F.J.
刊名: Atmospheric Research
ISSN: 1698095
出版年: 2019
卷: 223 起始页码: 74
结束页码: 87
语种: 英语
英文关键词: Complex terrain
; Horizontal convective rolls
; Large eddy simulation
; Open cellular convection
; Weather Research and forecasting Model
Scopus关键词: Aspect ratio
; Boundary layer flow
; Boundary layers
; Clouds
; Cytology
; Large eddy simulation
; Weather forecasting
; Complex terrains
; Convective boundary layers
; Horizontal convective rolls
; Numerical weather prediction
; Open cellular convection
; Transitional regimes
; Variability of structural properties
; Weather research and forecasting models
; Landforms
英文摘要: The nature of organized motions within the convective boundary layer (CBL) depends on the surface heating and vertical wind shear. Moderate surface heating and strong shear favor horizontal convective rolls, while strong surface heating and weak shear favor open cellular convection. The transition between rolls and cells over land, particularly complex terrain, is still poorly understood. Due to lack of adequate measurements, variability of structural properties of rolls and cells (such as aspect ratio, wavelength and orientation relative to the mean surface winds) over complex terrain remains unclear. At present resolutions used in operational numerical weather prediction, rolls and cells are now becoming partly resolved, but the reliability of their forecasting in complex terrain remains elusive. The main objective of this research is the investigation of the characteristics of rolls and cells in a mountain valley compared to flat terrain. To address this objective, we use the Weather Research and Forecasting Model (WRF) in LES mode. The domains cover the Owens Valley, California, the site of the Terrain-Induced Rotor Experiment (T-REX). We show that LES adequately simulated the complex valley-slope flow observed from flux towers and a wind profiler. Additionally, the vertical profiles of higher-order moments agree with those of textbook CBL behaviour. We found the transitional regime between rolls and cells to be broader compared to flat terrain when considering the bulk CBL stability parameter −z i /L. The width of the transitional regime depends on the temporal trend of −z i /L and the along-valley flow direction. Structural parameters of rolls and cells were different relative to their flat terrain counterparts, and a valley environment tends to introduce additional linearity into convection organization. Our results do not indicate a relationship between different convection modes and upslope flow strength. © 2019 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/122266
Appears in Collections: 气候变化事实与影响
There are no files associated with this item.
作者单位: Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtzplatz 1, Eggenstein-Leopoldshafen, 76344, Germany; Department of Environmental Sciences, University of Virginia, 291 McCormick Road, Charlottesville, VA 22904, United States
Recommended Citation:
Babić N.,De Wekker S.F.J.. Characteristics of roll and cellular convection in a deep and wide semiarid valley: A large-eddy simulation study[J]. Atmospheric Research,2019-01-01,223