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DOI	10.1007/s00382-018-4462-2
	Contrasting North–South changes in Amazon wet-day and dry-day frequency and related atmospheric features (1981–2017)
	Espinoza J.C.; Ronchail J.; Marengo J.A.; Segura H.
发表日期	2019
ISSN	0930-7575
起始页码	5413
结束页码	5430
卷号	52 期号:2020-09-10
英文摘要	This study provides an updated analysis of the evolution of seasonal rainfall intensity in the Amazon basin, considering the 1981–2017 period and based on HOP (interpolated HYBAM observed precipitation) and CHIRPS (The Climate Hazards Group Infrared Precipitation with Stations) rainfall data sets. Dry and wet day frequencies as well as extreme percentiles are used in this analysis, producing the same results. Dry-day frequency (DDF) significantly increases in the Southern Amazon (p < 0.01), particularly during September–November (SON) in the Bolivian Amazon, central Peruvian Amazon and far southern Brazilian Amazon. Consistently, total rainfall in the southern Amazon during SON also shows a significant diminution (p < 0.05), estimated at 18%. The increase in SON DDF in the southern Amazon is related to a warming of the northern tropical Atlantic Ocean and a weakening of water vapour flux from the tropical Atlantic Ocean. The increase in DDF in the southern Amazon is related to enhanced wind subsidence (ascendance) over the 10°S–20°S (5°S–5°N) region and to a deficit (excess) of specific humidity at 1000–300 hPa south of 10°S (north of the 5°S), which suggest a reduction of deep convection over southern Amazonia. Subsidence over the southern Amazon shows a significant trend (p < 0.01), which can explain the significant increase in DDF. Wet-day frequency (WDF) significantly increases in the northern Amazon, particularly during the March–May (MAM) period (p < 0.01), producing an estimated rainfall increase during MAM of 17% (p < 0.01) between 1981 and 2017. Significant changes in both WDF and rainfall in northern Amazon have been detected in 1998 (p < 0.01). After 1998, the increase in MAM WDF and rainfall is explained by enhanced moisture flux from the tropical North Atlantic Ocean and an increase in deep convection over the northern and northwestern Amazon. These evolutions in DDF and WDF and in the tropical atmosphere occur simultaneously with an increase in sea surface temperature in the northern Atlantic Ocean, particularly after the mid-1990s. These results provide new insight into rainfall variability and climatic features related to increasing dry season length in southern Amazonia. Severe recent droughts may be associated with the increase in DDF in the South. In addition, the increase in MAM rainfall intensity in northern Amazon after 1998 may be associated with several historical floods that occurred after this date. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
语种	英语
scopus关键词	convection; humidity; moisture flux; precipitation intensity; rainfall; sea surface temperature; seasonality; water vapor; Amazon Basin; Amazonia; Atlantic Ocean; Atlantic Ocean (Tropical); Bolivia; Peru
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/146348
作者单位	Instituto Geofísico del Perú (IGP), Calle Badajoz, 169, Mayorazgo IV Etapa, Ate, Lima, Peru; Univ. Paris Diderot and Sorbonne Paris Cité, UMR Locean (Sorbonne Universités-UPMC, CNRS, IRD, MNHN), Paris, France; Centro Nacional de Monitoramento e Alerta de Desastres Naturais (CEMADEN), São Paulo, Brazil; Université Grenoble-Alpes, UMR Geosciences of the Environment Laboratory-IGE (CNRS, Grenoble INP, IRD, UGA), Grenoble, France
推荐引用方式 GB/T 7714	Espinoza J.C.,Ronchail J.,Marengo J.A.,等. Contrasting North–South changes in Amazon wet-day and dry-day frequency and related atmospheric features (1981–2017)[J],2019,52(2020-09-10).
APA	Espinoza J.C.,Ronchail J.,Marengo J.A.,&Segura H..(2019).Contrasting North–South changes in Amazon wet-day and dry-day frequency and related atmospheric features (1981–2017).Climate Dynamics,52(2020-09-10).
MLA	Espinoza J.C.,et al."Contrasting North–South changes in Amazon wet-day and dry-day frequency and related atmospheric features (1981–2017)".Climate Dynamics 52.2020-09-10(2019).