DOI: 10.1016/j.atmosres.2017.06.002
Scopus记录号: 2-s2.0-85020814689
论文题名: The response of a simulated mesoscale convective system to increased aerosol pollution: Part II: Derecho characteristics and intensity in response to increased pollution
作者: Clavner M. ; Grasso L.D. ; Cotton W.R. ; van den Heever S.C.
刊名: Atmospheric Research
ISSN: 1698095
出版年: 2018
卷: 199 起始页码: 209
结束页码: 223
语种: 英语
英文关键词: Derecho
; MCS
; Pollution aerosols
; Straight-line winds
Scopus关键词: Aerosols
; Atmospheric movements
; Fighter aircraft
; Lakes
; Pollution
; Pollution control
; Precipitation (meteorology)
; Rain
; Storms
; Wind
; Anthropogenic aerosols
; Back trajectory analysis
; Chemical transport models
; Cloud condensation nuclei
; Derecho
; Mesoscale Convective System
; Non-monotonic response
; Regional atmospheric modeling systems
; Air pollution
; aerosol
; atmospheric pollution
; cloud condensation nucleus
; cloud microphysics
; concentration (composition)
; convective system
; mesoscale meteorology
英文摘要: Mesoscale Convective Systems (MCS) are important contributors to rainfall as well as producers of severe weather such as hail, tornados, and straight-line wind events known as derechos. In this study, different aerosol concentrations and their effects on a derecho event are examined by simulating a case study, the 8 May 2009 “Super-Derecho”, using the Regional Atmospheric Modeling System (RAMS), a cloud-resolving model with sophisticated aerosol and cloud microphysics. Three simulations were conducted that differed in the initial aerosol concentrations, spatial distribution and chemical composition as derived from output of GEOS-Chem, a 3D chemical transport model. In order to understand the impact of changes in aerosol concentrations on the derecho characteristics, the dynamical processes that produced the strong surface wind were determined by performing back-trajectory analysis during two periods of the simulated storm: the development and the onset of dissipation. A time dependent and non-monotonic trend was found between the intensity of the derecho and the increased aerosol concentrations that served as cloud condensation nuclei. During the formation period of the MCS, the non-monotonic trend was attributed to the microphysical impact of aerosol loading on the intensity of the cold pool; that is, the impact of aerosols on both the melting and evaporation rates of hydrometeors. The subsequent intensity changes within the cold pool modified the balance between the horizontal vorticity generated by the cold pool and that of the environment, thereby impacting the orientation of the convective updraft at the leading line. This, in turn, altered the primary flow that contributed to the formation of the derecho-strength surface winds. The simulation with no anthropogenic aerosols exhibited the strongest cold pool and the primary flow was associated with a descending rear inflow jet that produced the derecho winds over a larger region. The simulation with the highest amount of anthropogenic aerosols featured a stronger mesovortex and the derecho winds were primarily due to stronger convective downbursts. As the simulated storm matured, the changes in the derecho winds were found to be associated with the strength of the mesovortex at the gust front. During the period when the simulated storm began to dissipate, the non-monotonic trend in derecho intensity was associated with a non-monotonic response in mesovortex strength to increased aerosol concentrations. A moderate increase in aerosol concentrations led to the formation of a weaker mesovortex while a greater increase in aerosol concentration led to the formation of a stronger mesovortex. The formation of a stronger mesovortex was found to increase the contribution of the derecho winds following a convective downburst associated with an “up-down” downdraft trajectory. © 2017 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109031
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Atmospheric Science, Colorado State University, Fort Collins, CO, United States; Cooperative Institute for Research in the Atmosphere, Colorado State University, United States
Recommended Citation:
Clavner M.,Grasso L.D.,Cotton W.R.,et al. The response of a simulated mesoscale convective system to increased aerosol pollution: Part II: Derecho characteristics and intensity in response to increased pollution[J]. Atmospheric Research,2018-01-01,199