On the Role of the South Atlantic Atmospheric Circulation in Tropical Atlantic Variability

2013 ◽  
pp. 143-156 ◽  
Author(s):  
Marcelo Barreiro ◽  
Alessandra Giannini ◽  
Ping Chang ◽  
R. Saravanan
Keyword(s):  
Atmospheric Circulation ◽  
South Atlantic ◽  
Tropical Atlantic ◽  
The South ◽  
Tropical Atlantic Variability

scholarly journals Coupled Ocean–Atmosphere Variations over the South Atlantic Ocean

2012 ◽  
Vol 25 (18) ◽  
pp. 6349-6358 ◽  
Author(s):  
Paulo Nobre ◽  
Roberto A. De Almeida ◽  
Marta Malagutti ◽  
Emanuel Giarolla
Keyword(s):  
Atlantic Ocean ◽  
Atmospheric Circulation ◽  
General Circulation Model ◽  
General Circulation ◽  
Circulation Model ◽  
South Atlantic ◽  
Convergence Zone ◽  
Tropical Atlantic ◽  
The South ◽  
Ocean Atmosphere

Abstract The impact of ocean–atmosphere interactions on summer rainfall over the South Atlantic Ocean is explored through the use of coupled ocean–atmosphere models. The Brazilian Center for Weather Forecast and Climate Studies (CPTEC) coupled ocean–atmosphere general circulation model (CGCM) and its atmospheric general circulation model (AGCM) are used to gauge the role of coupled modes of variability of the climate system over the South Atlantic at seasonal time scales. Twenty-six years of summer [December–February (DJF)] simulations were done with the CGCM in ensemble mode and the AGCM forced with both observed sea surface temperature (SST) and SST generated by the CGCM forecasts to investigate the dynamics/thermodynamics of the two major convergence zones in the tropical Atlantic: the intertropical convergence zone (ITCZ) and the South Atlantic convergence zone (SACZ). The results present both numerical model and observational evidence supporting the hypothesis that the ITCZ is a thermally direct, SST-driven atmospheric circulation, while the SACZ is a thermally indirect atmospheric circulation controlling SST variability underneath—a consequence of ocean–atmosphere interactions not captured by the atmospheric model forced by prescribed ocean temperatures. Six CGCM model results of the Ensemble-based Predictions of Climate Changes and their Impacts (ENSEMBLES) project, NCEP–NCAR reanalysis data, and oceanic and atmospheric data from buoys of the Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) Project over the tropical Atlantic are used to validate CPTEC’s coupled and uncoupled model simulations.

scholarly journals Ocean Model Diagnosis of Interannual Coevolving SST Variability in the South Indian and South Atlantic Oceans

2005 ◽  
Vol 18 (15) ◽  
pp. 2864-2882 ◽  
Author(s):  
J. C. Hermes ◽  
C. J. C. Reason
Keyword(s):  
Atmospheric Circulation ◽  
Southern Hemisphere ◽  
Large Scale ◽  
Ocean Model ◽  
South Atlantic ◽  
Heat Fluxes ◽  
Global Ocean ◽  
The South ◽  
Sst Variability ◽  
South Indian

Abstract A global ocean model (ORCA2) forced with 50 yr of NCEP–NCAR reanalysis winds and heat fluxes has been used to investigate the evolution and forcing of interannual dipolelike sea surface temperature (SST) variability in the South Indian and South Atlantic Oceans. Although such patterns may also exist at times in only one of these basins and not the other, only events where there are coherent signals in both basins during the austral summer have been chosen for study in this paper. A positive (negative) event occurs when there is a significant warm (cool) SST anomaly evident in the southwest of both the South Indian and South Atlantic Oceans and a cool (warm) anomaly in the eastern subtropics. The large-scale forcing of these events appears to consist of a coherent modulation of the wavenumber-3 or -4 pattern in the Southern Hemisphere atmospheric circulation such that the semipermanent subtropical anticyclone in each basin is shifted from its summer mean position and its strength is modulated. A relationship to the Antarctic Oscillation is also apparent, and seems to strengthen after the mid-1970s. The modulated subtropical anticyclones lead to changes in the tropical easterlies and midlatitude westerlies in the South Atlantic and South Indian Oceans that result in anomalies in latent heat fluxes, upwelling, and Ekman heat transports, all of which contribute to the SST variability. In addition, there are significant modulations to the strong Rossby wave signals in the South Indian Ocean. The results of this study confirm the ability of the ORCA2 model to represent these dipole patterns and indicate connections between large-scale modulations of the Southern Hemisphere midlatitude atmospheric circulation and coevolving SST variability in the South Atlantic and South Indian Oceans.

Dual role of DOM in a scenario of global change on photosynthesis and structure of coastal phytoplankton from the South Atlantic Ocean

2018 ◽  
Vol 634 ◽  
pp. 1352-1361 ◽  
Author(s):  
Virginia E. Villafañe ◽  
Joanna Paczkowska ◽  
Agneta Andersson ◽  
Cristina Durán Romero ◽  
Macarena S. Valiñas ◽  
...  
Keyword(s):  
Global Change ◽  
Atlantic Ocean ◽  
South Atlantic ◽  
Dual Role ◽  
South Atlantic Ocean ◽  
The South ◽  
Coastal Phytoplankton

The role of SST on the South American atmospheric circulation during January, February and March 2001

2005 ◽  
Vol 24 (7-8) ◽  
pp. 781-791 ◽  
Author(s):  
Anita Rodrigues de Moraes Drumond ◽  
Tércio Ambrizzi
Keyword(s):  
Atmospheric Circulation ◽  
South American ◽  
The South

scholarly journals The Role of Interocean Exchanges on Decadal Variations of the Meridional Heat Transport in the South Atlantic

2011 ◽  
Vol 41 (8) ◽  
pp. 1498-1511 ◽  
Author(s):  
Shenfu Dong ◽  
Silvia Garzoli ◽  
Molly Baringer
Keyword(s):  
Indian Ocean ◽  
Heat Transport ◽  
South Atlantic ◽  
Similar Response ◽  
The South ◽  
Meridional Heat Transport ◽  
Interior Region ◽  
The Pacific ◽  
The Indian Ocean

Abstract The interocean exchange of water from the South Atlantic with the Pacific and Indian Oceans is examined using the output from the ocean general circulation model for the Earth Simulator (OFES) during the period 1980–2006. The main objective of this paper is to investigate the role of the interocean exchanges in the variability of the Atlantic meridional overturning circulation (AMOC) and its associated meridional heat transport (MHT) in the South Atlantic. The meridional heat transport from OFES shows a similar response to AMOC variations to that derived from observations: a 1 Sv (1 Sv ≡ 106 m3 s−1) increase in the AMOC strength would cause a 0.054 ± 0.003 PW increase in MHT at approximately 34°S. The main feature in the AMOC and MHT across 34°S is their increasing trends during the period 1980–93. Separating the transports into boundary currents and ocean interior regions indicates that the increase in transport comes from the ocean interior region, suggesting that it is important to monitor the ocean interior region to capture changes in the AMOC and MHT on decadal to longer time scales. The linear increase in the MHT from 1980 to 1993 is due to the increase in advective heat converged into the South Atlantic from the Pacific and Indian Oceans. Of the total increase in the heat convergence, about two-thirds is contributed by the Indian Ocean through the Agulhas Current system, suggesting that the warm-water route from the Indian Ocean plays a more important role in the northward-flowing water in the upper branch of the AMOC at 34°S during the study period.

scholarly journals Anomalous mid-twentieth century atmospheric circulation change over the South Atlantic compared to the last 6000 years

2016 ◽  
Vol 11 (6) ◽  
pp. 064009 ◽  
Author(s):  
Chris S M Turney ◽  
Richard T Jones ◽  
David Lister ◽  
Phil Jones ◽  
Alan N Williams ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Atmospheric Circulation ◽  
South Atlantic ◽  
The South ◽  
Circulation Change ◽  
Atmospheric Circulation Change

Southern by Degrees

2017 ◽  
Author(s):  
Isabel Hofmeyr
Keyword(s):  
Indian Ocean ◽  
South Atlantic ◽  
Literary Representations ◽  
The South ◽  
Anglophone Literature ◽  
Subantarctic Islands ◽  
Imperial Expansion ◽  
The Indian Ocean ◽  
The Antarctic

From the perspective of Anglophone literature, the South Atlantic has been something of a blank—in colonial maritime fiction, a prefatory space leading up to the Cape of Storms or on the journey home, a fast-forward space as the ship hurries to the metropole. This article suggests that one way to fill this blank is to focus on the subantarctic islands of the South Atlantic and the Indian Ocean. This insular world played a key role in the scramble for the Antarctic and reproduces the role of islands in imperial expansion elsewhere. The article examines two contrasting literary representations of these island worlds: H. Rider Haggard’s novel Mary of Marion Isle and Yvette Christiansë’s collection of poetry Imprendehora.

scholarly journals The South Atlantic Anticyclone as a key player for the representation of the tropical Atlantic climate in coupled climate models

2016 ◽  
Vol 48 (11-12) ◽  
pp. 4051-4069 ◽  
Author(s):  
William Cabos ◽  
Dmitry V. Sein ◽  
Joaquim G. Pinto ◽  
Andreas H. Fink ◽  
Nikolay V. Koldunov ◽  
...  
Keyword(s):  
Climate Models ◽  
South Atlantic ◽  
Tropical Atlantic ◽  
The South ◽  
Coupled Climate Models
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