Publication Date:
2022-05-26
Description:
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Finke, K., Jimenez-Esteve, B., Taschetto, A. S., Ummenhofer, C. C., Bumke, K., & Domeisen, D. I., V. Revisiting remote drivers of the 2014 drought in South-Eastern Brazil. Climate Dynamics, (2020), doi:10.1007/s00382-020-05442-9.
Description:
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.
Description:
K.F. was partially supported by the GEOMAR Marine Meteorology research area. Support to D.D. and B.J-E. from the Swiss National Science Foundation through project PP00P2_170523 is gratefully acknowledged. This research was supported by a Research Fellowship by the Alexander von Humboldt Foundation and the Early Career Scientist Endowed Fund and The George E. Thibault Early Career Scientist Fund to C.C.U. A.S.T. is supported by the Australian Research Council FT160100495.
Open access funding provided by Swiss Federal Institute of Technology Zurich.
Keywords:
Brazil 2014 drought
;
Teleconnection
;
ENSO
;
Blocking
;
MJO
Repository Name:
Woods Hole Open Access Server
Type:
Article
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