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.

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 A ÁFRICA DO SUL, O ATLÂNTICO SUL E A EQUAÇÃO IBAS-BRICS: O ESPAÇO TRANSATLÂNTICO EM TRANSIÇÃO

2013 ◽  
Vol 2 (3) ◽  
pp. 77-106 ◽  
Author(s):  
Francis Kornegay
Keyword(s):  
South Africa ◽  
Developing Countries ◽  
Indian Ocean ◽  
South Atlantic ◽  
Great Powers ◽  
African Continent ◽  
The South ◽  
The Indian Ocean

In a context of increasing South-South cooperation, the members of an important trilateral dialogue forum that represent the emergent powers – IBSA –, have been incorporated into another organization, BRICS. It resulted from an overlap of the Southern developing countries into the domain of the Euro-Asiatic great powers. Bearing in mind that both alliances are centered on the geostrategic space of the Indian Ocean and the South Atlantic, South Africa´s South Atlantic strategic potential in tandem with Brazil is of extreme importance. It is possible to differentiate two steams in the transatlantic ties: the Afro-Latin and the trans-Mediterranean.  It is also relevant to place the role of Angola in the African continent as a possible influence in South Atlantic´s dynamics, given due importance to the Lusophone ties which are represented by CPLP.

scholarly journals Role of the Indian Ocean in the Biennial Transition of the Indian Summer Monsoon

2007 ◽  
Vol 20 (10) ◽  
pp. 2147-2164 ◽  
Author(s):  
Renguang Wu ◽  
Ben P. Kirtman
Keyword(s):  
Indian Ocean ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Indian Monsoon ◽  
Coupled Model ◽  
The Pacific ◽  
The Indian Ocean ◽  
Biennial Variability ◽  
Sst Anomalies

Abstract The biennial variability is a large component of year-to-year variations in the Indian summer monsoon (ISM). Previous studies have shown that El Niño–Southern Oscillation (ENSO) plays an important role in the biennial variability of the ISM. The present study investigates the role of the Indian Ocean in the biennial transition of the ISM when the Pacific ENSO is absent. The influence of the Indian and Pacific Oceans on the biennial transition between the ISM and the Australian summer monsoon (ASM) is also examined. Controlled numerical experiments with a coupled general circulation model (CGCM) are used to address the above two issues. The CGCM captures the in-phase ISM to ASM transition (i.e., a wet ISM followed by a wet ASM or a dry ISM followed by a dry ASM) and the out-of-phase ASM to ISM transition (i.e., a wet ASM followed by a dry ISM or a dry ASM followed by a wet ISM). These transitions are more frequent than the out-of-phase ISM to ASM transition and the in-phase ASM to ISM transition in the coupled model, consistent with observations. The results of controlled coupled model experiments indicate that both the Indian and Pacific Ocean air–sea coupling are important for properly simulating the biennial transition between the ISM and ASM in the CGCM. The biennial transition of the ISM can occur through local air–sea interactions in the north Indian Ocean when the Pacific ENSO is suppressed. The local sea surface temperature (SST) anomalies induce the Indian monsoon transition through low-level moisture convergence. Surface evaporation anomalies, which are largely controlled by surface wind speed changes, play an important role for SST changes. Different from local air–sea interaction mechanisms proposed in previous studies, the atmospheric feedback is not strong enough to reverse the SST anomalies immediately at the end of the monsoon season. Instead, the reversal of the SST anomalies is accomplished in the spring of the following year, which in turn leads to the Indian monsoon transition.

Arabic as a Language of the South Asian Chancery: Bahmani Communications to the Mamluk Sultanate

Arabica ◽  
2020 ◽  
Vol 67 (4) ◽  
pp. 409-435
Author(s):  
Meia Walravens
Keyword(s):  
Indian Ocean ◽  
Fifteenth Century ◽  
Red Sea ◽  
South Asian ◽  
Cultural Exchange ◽  
The South ◽  
Growing Body ◽  
The Indian Ocean

Abstract A growing body of literature on trade and cultural exchange between the Indian Ocean regions has already contributed significantly to our understanding of these processes and the role of language and writing within them. Yet, the question remains how Arabic correspondence played a part in communications between South Asian powers and the rulers in the Red Sea region. In order to begin filling this lacuna, this article studies epistolary writings from the Bahmani Sultanate (748/1347-934/1528) to the Mamluk Sultanate (648/1250-922/1517) during the second half of the ninth/fifteenth century. The contextualisation and discussion of three letters render insight both into the (up to now unstudied) issues at play in Bahmani-Mamluk relations and into the nature of these Arabic texts.

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

2020 ◽  
Vol 55 (11-12) ◽  
pp. 3197-3211
Author(s):  
Kathrin Finke ◽  
Bernat Jiménez-Esteve ◽  
Andréa S. Taschetto ◽  
Caroline C. Ummenhofer ◽  
Karl Bumke ◽  
...  
Keyword(s):  
Indian Ocean ◽  
General Circulation ◽  
Circulation Model ◽  
Tropical Pacific ◽  
South Atlantic ◽  
The South ◽  
South Eastern ◽  
Eastern Brazil ◽  
The Indian Ocean ◽  
Sst Anomalies

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.

The rare deep-living hyperiid amphipod Megalanceoloides remipes (Barnard, 1932): complementary description and symbiosis

Zootaxa ◽  
2016 ◽  
Vol 4178 (1) ◽  
pp. 138 ◽  
Author(s):  
REBECA GASCA ◽  
STEVEN H.D. HADDOCK
Keyword(s):  
Pacific Ocean ◽  
Indian Ocean ◽  
Gulf Of California ◽  
South Atlantic ◽  
Symbiotic Association ◽  
The Pacific ◽  
The Indian Ocean ◽  
The Pacific Ocean ◽  
In Situ Observations

A female ovigerous specimen of the rare deep-living hyperiid Megalanceoloides remipes (Barnard, 1932) was collected with a remotely operated submersible (ROV) at a depth of 2,094 m in the Farallon Basin, Gulf of California. The specimen was found to be symbiotically associated with the siphonophore Apolemia sp. Eschscholtz, 1829. Hitherto, this species was known only from two other specimens, one from the South Atlantic and another from the Indian Ocean; the present record is the first from the Pacific Ocean. Previous descriptions lacked morphological details of different appendages; these data are provided here. In addition, we present the first data on its symbiotic association from in situ observations. The colors of the hyperiid and of some parts of the Apolemid were very similar, thus supporting the notion that some hyperiids tend to mimic the color of its host. 

scholarly journals Role of Indian and Pacific SST in Indian Summer Monsoon Intraseasonal Variability

2011 ◽  
Vol 24 (12) ◽  
pp. 2915-2930 ◽  
Author(s):  
Deepthi Achuthavarier ◽  
V. Krishnamurthy
Keyword(s):  
Indian Ocean ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
General Circulation ◽  
Singular Spectrum Analysis ◽  
Intraseasonal Variability ◽  
Circulation Model ◽  
The Pacific ◽  
The Indian Ocean

Abstract Three regionally coupled experiments are conducted to examine the role of Indian and Pacific sea surface temperature (SST) in Indian summer monsoon intraseasonal variability using the National Centers for Environmental Prediction’s Climate Forecast System, a coupled general circulation model. Regional coupling is employed by prescribing daily mean or climatological SST in either the Indian or the Pacific basin while allowing full coupling elsewhere. The results are compared with a fully coupled control simulation. The intraseasonal modes are isolated by applying multichannel singular spectrum analysis on the daily precipitation anomalies. It is found that the amplitude of the northeastward-propagating mode is weaker when the air–sea interaction is suppressed in the Indian Ocean. The intraseasonal mode is not resolved clearly when the Indian Ocean SST is reduced to daily climatology. Intraseasonal composites of low-level zonal wind, latent heat flux, downward shortwave radiation, and SST provide a picture consistent with the proposed mechanisms of air–sea interaction for the northward propagation. The Pacific SST variability does not seem to be critical for the existence of this mode. The northwestward-propagating mode is obtained in the cases where the Indian Ocean was prescribed by daily mean or daily climatological SST. Intraseasonal SST composites corresponding to this mode are weak.

scholarly journals Influences of Pacific Climate Variability on Decadal Subsurface Ocean Heat Content Variations in the Indian Ocean

2018 ◽  
Vol 31 (10) ◽  
pp. 4157-4174 ◽  
Author(s):  
Xiaolin Jin ◽  
Young-Oh Kwon ◽  
Caroline C. Ummenhofer ◽  
Hyodae Seo ◽  
Franziska U. Schwarzkopf ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Boundary Conditions ◽  
Heat Content ◽  
Western Indian Ocean ◽  
Ocean Heat Content ◽  
Ekman Pumping ◽  
Subsurface Ocean ◽  
The Pacific ◽  
The Indian Ocean

Abstract Decadal variabilities in Indian Ocean subsurface ocean heat content (OHC; 50–300 m) since the 1950s are examined using ocean reanalyses. This study elaborates on how Pacific variability modulates the Indian Ocean on decadal time scales through both oceanic and atmospheric pathways. High correlations between OHC and thermocline depth variations across the entire Indian Ocean Basin suggest that OHC variability is primarily driven by thermocline fluctuations. The spatial pattern of the leading mode of decadal Indian Ocean OHC variability closely matches the regression pattern of OHC on the interdecadal Pacific oscillation (IPO), emphasizing the role of the Pacific Ocean in determining Indian Ocean OHC decadal variability. Further analyses identify different mechanisms by which the Pacific influences the eastern and western Indian Ocean. IPO-related anomalies from the Pacific propagate mainly through oceanic pathways in the Maritime Continent to impact the eastern Indian Ocean. By contrast, in the western Indian Ocean, the IPO induces wind-driven Ekman pumping in the central Indian Ocean via the atmospheric bridge, which in turn modifies conditions in the southwestern Indian Ocean via westward-propagating Rossby waves. To confirm this, a linear Rossby wave model is forced with wind stresses and eastern boundary conditions based on reanalyses. This linear model skillfully reproduces observed sea surface height anomalies and highlights both the oceanic connection in the eastern Indian Ocean and the role of wind-driven Ekman pumping in the west. These findings are also reproduced by OGCM hindcast experiments forced by interannual atmospheric boundary conditions applied only over the Pacific and Indian Oceans, respectively.

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