气候变化领域集成服务门户(CCPortal): Observed relationship between the Turkana low-level jet and boreal summer convection

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DOI	10.1007/s00382-019-04769-2
	Observed relationship between the Turkana low-level jet and boreal summer convection
	Vizy E.K.; Cook K.H.
发表日期	2019
ISSN	0930-7575
起始页码	4037
结束页码	4058
卷号	53 期号:2020-07-08
英文摘要	The Turkana low-level jet is a circulation feature over northern Kenya that is not spatially well-resolved in many observational datasets. Here, high-resolution TRMM, IMERG, and CMORPH precipitation estimates, along with the ERA5 and MERRA2 reanalyses are analyzed to better understand the controls on jet strength and the relationship between the jet and boreal summer rainfall variability in the jet exit region over South Sudan. The height of the South Sudan wet season, August, is analyzed for 2000–2017. Climatologically, rainfall peaks over the jet exit region during the early morning hours, coinciding with the jet maximum. The strong jet enhances low-level wind convergence and briefly shifts the low-level zonal moisture gradient westward. Over the western South Sudan, rainfall peaks in the late afternoon/evening in association with daytime heating. The correlation between the daily Turkana Jet strength and precipitation indicates a significant negative relationship over eastern South Sudan, and over the Ethiopian and East African Highlands. Composite analysis of strong and weak jet periods reveal that the atmospheric conditions associated with a strong jet include enhanced low-level ridging along the East African coast south of the equator resulting in a stronger height gradient in the Turkana Channel, as well drier conditions over the channel and adjacent highlands. These conditions support a stronger jet that is further enhanced by katabatic flow due to the stronger nighttime cooling over the highlands, as well as enhanced dry air advection over the jet exit region. Thus, while low-level convergence may increase, convection weakens over eastern South Sudan due to the reduced atmospheric moisture content and weaker instability. The opposite occurs for the weak jet case. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Diurnal cycle of rainfall; East African rainfall; ERA5; Ethiopia; IMERG; Katabatic winds; Kenya; Rainfall variability; South Sudan; Turkana low-level jet
语种	英语
scopus关键词	atmospheric convection; diurnal variation; jet stream; katabatic flow; rainfall; summer; wind; Kenya; South Sudan; Turkana
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/145995
作者单位	Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX 78712, United States
推荐引用方式 GB/T 7714	Vizy E.K.,Cook K.H.. Observed relationship between the Turkana low-level jet and boreal summer convection[J],2019,53(2020-07-08).
APA	Vizy E.K.,&Cook K.H..(2019).Observed relationship between the Turkana low-level jet and boreal summer convection.Climate Dynamics,53(2020-07-08).
MLA	Vizy E.K.,et al."Observed relationship between the Turkana low-level jet and boreal summer convection".Climate Dynamics 53.2020-07-08(2019).