气候变化领域集成服务门户(CCPortal): Recent changes in the precipitation-driving processes over the southern tropical Andes/western Amazon

CCPortal

DOI	10.1007/s00382-020-05132-6
	Recent changes in the precipitation-driving processes over the southern tropical Andes/western Amazon
	Segura H.; Espinoza J.C.; Junquas C.; Lebel T.; Vuille M.; Garreaud R.
发表日期	2020
ISSN	0930-7575
起始页码	2613
结束页码	2631
卷号	54
英文摘要	Analyzing December–February (DJF) precipitation in the southern tropical Andes—STA (12∘S–20∘S; > 3000 m.a.s.l) allows revisiting regional atmospheric circulation features accounting for its interannual variability over the past 35 years (1982–2018). In a region where in-situ rainfall stations are sparse, the CHIRPS precipitation product is used to identify the first mode of interannual DJF precipitation variability (PC1-Andes). A network of 98 rain-gauge stations further allows verifying that PC1-Andes properly represents the spatio-temporal rainfall distribution over the region; in particular a significant increase in DJF precipitation over the period of study is evident in both in-situ data and PC1-Andes. Using the ERA-Interim data set, we found that aside from the well-known relationship between precipitation and upper-level easterlies over the STA, PC1-Andes is also associated with upward motion over the western Amazon (WA), a link that has not been reported before. The ascent over the WA is a component of the meridional circulation between the tropical North Atlantic and western tropical South America—WTSA (80∘W–60∘W; 35∘S–10∘N). Indeed, the precipitation increase over the last 2 decades is concomitant with the strengthening of this meridional circulation. An intensified upward motion over the WA has moistened the mid-troposphere over WTSA, and as a consequence, a decreased atmospheric stability between the mid- and the upper troposphere is observed over this region, including the STA. We further show that, over the last 15 years or so, the year-to-year variability of STA precipitation (periodicity < 8 years) has been significantly associated with upward motion over the WA, while upper-level easterlies are no longer significantly correlated with precipitation. These observations suggests that the STA have experienced a transition from a dry to a wet state in association with a change in the dominant mode of atmospheric circulation. In the former dominant state, zonal advection of momentum and moisture from the central Amazon, associated with upper-level easterlies, is necessary to develop convection over the STA. Since the beginning of the 21st century, DJF precipitation over the STA seems to respond directly and primarily to upward motion over the WA. Beyond improving our understanding of the factors influencing STA precipitation nowadays, these results point to the need of exploring their possible implications for the long-term evolution of precipitation in a context of global warming. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Altiplano precipitation; Amazon convection; Amazon-Andes connectivity; South America atmospheric circulation
语种	英语
scopus关键词	annual variation; atmospheric circulation; atmospheric convection; precipitation (climatology); rainfall; troposphere; Altiplano; Amazonia; Andes
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/145566
作者单位	Univ. Grenoble Alpes, IRD, CNRS, Grenoble INP, IGE, Grenoble, 38000, France; Department of Atmospheric and Environmental Sciences, State University of New York at Albany, Albany, NY, United States; Center for Climate and Resilience Research (CR2, FONDAP 15110009), Santiago, Chile; Department of Geophysics, Universidad de Chile, Santiago, Chile
推荐引用方式 GB/T 7714	Segura H.,Espinoza J.C.,Junquas C.,et al. Recent changes in the precipitation-driving processes over the southern tropical Andes/western Amazon[J],2020,54.
APA	Segura H.,Espinoza J.C.,Junquas C.,Lebel T.,Vuille M.,&Garreaud R..(2020).Recent changes in the precipitation-driving processes over the southern tropical Andes/western Amazon.Climate Dynamics,54.
MLA	Segura H.,et al."Recent changes in the precipitation-driving processes over the southern tropical Andes/western Amazon".Climate Dynamics 54(2020).