DOI: 10.1002/2014JD021962
论文题名: Impact of resolution on simulation of closed mesoscale cellular convection identified by dynamically guided watershed segmentation
作者: Martini M.N. ; Gustafson W.I. ; Jr. ; Yang Q. ; Xiao H.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 2169897X
出版年: 2014
卷: 119, 期: 22 起始页码: 12674
结束页码: 12688
语种: 英语
英文关键词: cloud detection
; marine stratocumulus
; mesoscale cellular convection
; organized MCC
; watershed segmentation
; WRF
Scopus关键词: automation
; boundary layer
; cloud microphysics
; marine ecosystem
; mesoscale meteorology
; satellite imagery
; simulation
; stratocumulus
; watershed
英文摘要: Organized mesoscale cellular convection (MCC) is a common feature of marine stratocumulus clouds that forms in response to interactions among dynamic, microphysical, and radiative processes at the mesoscale. Cloud resolving models begin to resolve some of these processes, but using high resolutions is extremely costly. To understand the impact of limited resolution on MCC, we use the Weather Research and Forecasting model with chemistry and fully coupled cloud-aerosol interactions to simulate MCC over the southeast Pacific during the Variability of the American Monsoon Systems Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx). A suite of experiments with 3 and 9 km grid spacing indicates that the simulations with finer grid spacing have smaller liquid water paths and cloud fractions, while cloud tops are higher. The observed diurnal cycle is reasonably well simulated. To isolate organized MCC characteristics, we develop a new automated method that uses the watershed segmentation combining the detection of cloud boundaries with coincident vertical velocities. This ensures that the detected cloud fields are dynamically consistent for closed MCC, a common feature within the VOCALS-REx region. We demonstrate that the 3 km simulation is able to reproduce the scaling between horizontal cell size and boundary layer depth seen in satellite observations for the conditions of 900-1400 m deep boundary layers. However, the 9 km simulation is unable to resolve smaller circulations corresponding to shallower boundary layers, instead producing MCC with an invariant horizontal scale for all simulated boundary layers depths. The results demonstrate that the grid spacing needed for proper simulation of the MCC structure in marine stratocumulus regions depends on the boundary layer depth. ©2014. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63041
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, United States
Recommended Citation:
Martini M.N.,Gustafson W.I.,Jr.,et al. Impact of resolution on simulation of closed mesoscale cellular convection identified by dynamically guided watershed segmentation[J]. Journal of Geophysical Research Atmospheres,2014-01-01,119(22)