气候变化领域集成服务门户(CCPortal): Impacts of the Westerlies on Planetary Boundary Layer Growth Over a Valley on the North Side of the Central Himalayas

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DOI	10.1029/2020JD033928
	Impacts of the Westerlies on Planetary Boundary Layer Growth Over a Valley on the North Side of the Central Himalayas
	Lai Y.; Chen X.; Ma Y.; Chen D.; Zhaxi S.
发表日期	2021
ISSN	2169897X
卷号	126 期号:3
英文摘要	This study focused on planetary boundary layer (PBL) growth in winter under the influence of the westerlies over the Rongbuk Valley on the north side of the central Himalayas. Two sunny November days in 2014 with different synoptic conditions in terms of large-scale wind direction and speed were selected to investigate the ways in which large-scale synoptic forcing affected the vertical structure of the PBL, atmospheric stability, surface wind field, and land surface energy fluxes. This was done by using radiosonde and in-situ measurements, the European Centre for Medium-Range Weather Forecasts ERA5 reanalysis data set, and a one-dimensional model. The results revealed that the valley winds and PBL growth were strongly influenced by the variations of the westerlies, which prevail in this region during the winter. When the synoptic wind direction at the height of the mountain ridges was parallel to the axis of the valley and strong, the downward transmission of the westerlies to the valley floor (DTWTV) was strong, causing high near-surface wind speeds and sensible heat flux values. These conditions, together with a deep residual layer, unstable atmosphere, and thermally driven local wind, produced an extremely deep PBL (9 km above sea level) in the early afternoon of November 23. When the synoptic wind direction at the ridge height intersected the axis of the valley and was weak, the DTWTV was weak, and the PBL became relatively low on November 28. These results demonstrate that the interaction between the topography and synoptic circulation plays a critical role in PBL growth. © 2020. American Geophysical Union. All Rights Reserved.
英文关键词	Himalayas; planetary boundary layer; thermally driven wind; Tibetan Plateau; westerlies
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/185516
作者单位	Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China; Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing, China; Regional Climate Group, Department of Earth Science, University of Gothenburg, Gothenburg, Sweden; Medog Meteorological Bureau, Nyingchi, China
推荐引用方式 GB/T 7714	Lai Y.,Chen X.,Ma Y.,et al. Impacts of the Westerlies on Planetary Boundary Layer Growth Over a Valley on the North Side of the Central Himalayas[J],2021,126(3).
APA	Lai Y.,Chen X.,Ma Y.,Chen D.,&Zhaxi S..(2021).Impacts of the Westerlies on Planetary Boundary Layer Growth Over a Valley on the North Side of the Central Himalayas.Journal of Geophysical Research: Atmospheres,126(3).
MLA	Lai Y.,et al."Impacts of the Westerlies on Planetary Boundary Layer Growth Over a Valley on the North Side of the Central Himalayas".Journal of Geophysical Research: Atmospheres 126.3(2021).