Revisiting remote drivers of the 2014 drought in South-Eastern Brazil

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Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_EFCBF99E8B08
Type
Article: article from journal or magazin.
Collection
Publications
Title
Revisiting remote drivers of the 2014 drought in South-Eastern Brazil
Journal
Climate Dynamics
Author(s)
Finke Kathrin, Jiménez-Esteve Bernat, Taschetto Andréa S., Ummenhofer Caroline C., Bumke Karl, Domeisen Daniela I. V.
ISSN
0930-7575
1432-0894
Publication state
Published
Issued date
12/2020
Peer-reviewed
Oui
Volume
55
Number
11-12
Pages
3197-3211
Language
english
Abstract
South-Eastern Brazil experienced a devastating drought associated with significant agricultural losses in austral summer 2014. The drought was linked to the development of a quasi-stationary anticyclone in the South Atlantic in early 2014 that affected local precipitation patterns over South-East Brazil. Previous studies have suggested that the unusual blocking was triggered by tropical Pacific sea surface temperature (SST) anomalies and, more recently, by convection over the Indian Ocean related to the Madden–Julian Oscillation. Further investigation of the proposed teleconnections appears crucial for anticipating future economic impacts. In this study, we use numerical experiments with an idealized atmospheric general circulation model forced with the observed 2013/2014 SST anomalies in different ocean basins to understand the dominant mechanism that initiated the 2014 South Atlantic anticyclonic anomaly. We show that a forcing with global 2013/2014 SST anomalies enhances the chance for the occurrence of positive geopotential height anomalies in the South Atlantic. However, further sensitivity experiments with SST forcings in separate ocean basins suggest that neither the Indian Ocean nor tropical Pacific SST anomalies alone have contributed significantly to the anomalous atmospheric circulation that led to the 2014 South-East Brazil drought. The model study rather points to an important role of remote forcing from the South Pacific, local South Atlantic SSTs, and internal atmospheric variability in driving the persistent blocking over the South Atlantic.
Keywords
Brazil 2014 drought, Teleconnection, ENSO, Blocking, MJO
Pubmed
Web of science
Open Access
Yes
Funding(s)
Swiss National Science Foundation / PP00P2_170523
Create date
08/03/2022 15:13
Last modification date
11/07/2024 10:37
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