DOI: 10.1007/s00382-015-2800-1
Scopus记录号: 2-s2.0-84939247891
论文题名: The 2014 southeast Brazil austral summer drought: regional scale mechanisms and teleconnections
作者: Coelho C.A.S. ; de Oliveira C.P. ; Ambrizzi T. ; Reboita M.S. ; Carpenedo C.B. ; Campos J.L.P.S. ; Tomaziello A.C.N. ; Pampuch L.A. ; Custódio M.S. ; Dutra L.M.M. ; Da Rocha R.P. ; Rehbein A.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2016
卷: 46, 期: 2017-11-12 起始页码: 3737
结束页码: 3752
语种: 英语
英文关键词: Austral summer
; Drought
; Precipitation
; Sea surface temperature
; Southeast Brazil
; Teleconnections
英文摘要: The southeast region of Brazil experienced in austral summer 2014 a major drought event leading to a number of impacts in water availability for human consumption, agricultural irrigation and hydropower production. This study aims to perform a diagnostic analysis of the observed climate conditions during this event, including an inspection of the occurred precipitation anomalies in the context of previous years, and an investigation of possible relationships with sea surface temperatures and atmospheric circulation patterns. The sea surface temperature analysis revealed that the southwestern South Atlantic Ocean region near the coast of southeast Brazil showed strong negative association with precipitation over southeast Brazil, indicating that increased sea temperatures in this ocean region are consistent with reduced precipitation as observed in summer 2014. The circulation analysis revealed prevailing anti-cyclonic anomalies at lower levels (850 hPa) with northerly anomalies to the west of southeast Brazil, channeling moisture from the Amazon towards Paraguay, northern Argentina and southern Brazil, and drier than normal air from the South Atlantic Ocean towards the southeast region of Brazil. This circulation pattern was found to be part of a large-scale teleconnection wave train linked with the subsidence branch of the Walker circulation in the tropical east Pacific, which in turn was generated by an anomalous tropical heat source in north/northeastern Australia. A regional Hadley circulation with an ascending branch to the south of the subsidence branch of the Walker circulation in the tropical east Pacific was identified as an important component connecting the tropical and extratropical circulation. The ascending branch of this Hadley circulation in the south Pacific coincided with an identified Rossby wave source region, which contributed to establishing the extratropical component of the large-scale wave train connecting the south Pacific and the Atlantic region surrounding southeast Brazil. This connection between the Pacific and the Atlantic was confirmed with Rossby ray tracing analyses. The local circulation response was associated to downward air motion (subsidence) over Southeast Brazil, contributing to the expressive negative precipitation anomalies observed during summer 2014, and leading to a major drought event in the historical context. The analysis of atmospheric and oceanic patterns of this event helped defining a schematic framework leading to the observed drought conditions in southeast Brazil, including the involved teleconnections, blocking high pressure, radiative and humidity transport effects. © 2015, Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53728
Appears in Collections: 过去全球变化的重建
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作者单位: Centro de Previsão de Tempo e Estudos Climáticos (CPTEC), Instituto Nacional de Pesquisas Espaciais (INPE), Rodovia Presidente Dutra, Km 40, SP-RJ, Cachoeira Paulista, SP, Brazil; Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG), Universidade de São Paulo (USP), Rua do Matão, 1226, São Paulo, SP, Brazil; Instituto de Recursos Naturais, Universidade Federal de Itajubá (UNIFEI), Av BPS, 1303, Itajubá, MG, Brazil
Recommended Citation:
Coelho C.A.S.,de Oliveira C.P.,Ambrizzi T.,et al. The 2014 southeast Brazil austral summer drought: regional scale mechanisms and teleconnections[J]. Climate Dynamics,2016-01-01,46(2017-11-12)