气候变化领域集成服务门户(CCPortal): The Effect of Upstream Orography on the Onset of Sundowner Winds in Coastal Santa Barbara, CA

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DOI	10.1029/2020JD033791
	The Effect of Upstream Orography on the Onset of Sundowner Winds in Coastal Santa Barbara, CA
	Duine G.-J.; Carvalho L.M.V.; Jones C.; Zigner K.
发表日期	2021
ISSN	2169897X
卷号	126 期号:8
英文摘要	The impact of upstream terrain on the diurnal variability of downslope windstorms on the south-facing slopes of the Santa Ynez Mountains (SYM) is investigated using numerical simulations. These windstorms, called Sundowners due to their typical onset around sunset, have intensified all major wildfires in the area. This study investigates the role of the orography upstream of the SYM in the diurnal behavior of Sundowners. Two types of Sundowners are examined: western sundowners (winds with dominant northwesterly direction) and eastern Sundowners (winds with dominant northeasterly direction). By using semi-idealized simulations, in which we progressively reduce the upstream terrain, we show that the onset of the lee slope jet occurs in the late afternoon only when the flow approaches the SYM from the northeast, after interacting with a considerably higher mountain barrier. We demonstrate that during the eastern regime, the progressive reduction of the upstream terrain results in strong lee slope winds throughout the day. Conversely, the diurnal cycle of downslope winds during the western regime is less sensitive to the reduction of the upstream terrain. The Sundowner diurnal cycle during the eastern regime can be explained by boundary-layer processes in the valley and the blocking effect of high mountains upstream of the SYM. These results contribute to a better understanding of the influence of upstream orography in the cycle and intensity of downslope windstorms in coastal mountains. © 2021. American Geophysical Union. All Rights Reserved.
英文关键词	atmospheric boundary layer; downslope windstorms; WRF mesoscale simulations
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185310
作者单位	Earth Research Institute, University of California, Santa Barbara, CA, United States; Department of Geography, University of California, Santa Barbara, CA, United States
推荐引用方式 GB/T 7714	Duine G.-J.,Carvalho L.M.V.,Jones C.,et al. The Effect of Upstream Orography on the Onset of Sundowner Winds in Coastal Santa Barbara, CA[J],2021,126(8).
APA	Duine G.-J.,Carvalho L.M.V.,Jones C.,&Zigner K..(2021).The Effect of Upstream Orography on the Onset of Sundowner Winds in Coastal Santa Barbara, CA.Journal of Geophysical Research: Atmospheres,126(8).
MLA	Duine G.-J.,et al."The Effect of Upstream Orography on the Onset of Sundowner Winds in Coastal Santa Barbara, CA".Journal of Geophysical Research: Atmospheres 126.8(2021).