Revisiting remote drivers of the 2014 drought in South-Eastern Brazil
- PDF / 5,832,774 Bytes
- 15 Pages / 595.276 x 790.866 pts Page_size
- 77 Downloads / 165 Views
Revisiting remote drivers of the 2014 drought in South‑Eastern Brazil Kathrin Finke1 · Bernat Jiménez‑Esteve2 · Andréa S. Taschetto3,4 · Caroline C. Ummenhofer4,5 · Karl Bumke6 · Daniela I. V. Domeisen2 Received: 23 April 2019 / Accepted: 23 August 2020 © The Author(s) 2020
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
1 Introduction
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00382-020-05442-9) contains supplementary material, which is available to authorized users. * Daniela I. V. Domeisen [email protected] 1
Department of Meteorology, Stockholm University, Stockholm, Sweden
2
Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
3
Climate Change Research Centre, University of New South Wales, Sydney, Australia
4
ARC Centre of Excellence for Climate Extremes, University of New South Wales, Sydney, Australia
5
Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, USA
6
Marine Meteorology Department, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Agriculture represents an important part of Brazil’s economy. Products differ regionally depending on the local climate. The climate in South-Eastern (SE) Brazil, particularly in the states Minas Gerais and Espírito Santo, provides ideal growing conditions favorable for the development of large coffee plantations (de Camargo
Data Loading...
