The Role of the Indian Ocean Basin-Wide and El Niño–Southern Oscillation Modes in Interannual Rainfall Variability over South America during Austral Summer

Kayano, Mary Toshie; Andreoli, Rita V.; Cerón, Wilmar Loaiza; Souza, R. A. F. D.

doi:10.3390/atmos12091094

Cited by 5 publications

(10 citation statements)

References 53 publications

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“…The data sources are the same as those used by Kayano et al [14]. The SST and precipitation data were obtained from the National Oceanic and Atmospheric Administration extended reconstructed SST version V5 [33,34] and the Global Precipitation Climatology Centre Full Data Reanalysis V2018 version [35,36] datasets.…”

Section: Methodsmentioning

confidence: 99%

“…Following Kayano et al [14], the ENSO and IOD indices were obtained from the empirical orthogonal function (EOF) analyses of the filtered SON SST anomalies in the tropical Pacific Ocean (TPO; 30 S, 30 • E, and 120 • E) during the 1951-2016 period. The EOF analyses were calculated separately in each oceanic sector.…”

Section: Methodsmentioning

confidence: 99%

“…Taschetto and Ambrizzi [13] provided modeling and diagnostic evidence that the warm IOBW event strengthens the EN-related atmospheric circulation and rainfall anomalies over SA and contributes to the persistent dryness over northeastern Brazil (NEB) during austral autumn. Meanwhile, Kayano et al [14] found opposite effects of the EN and warm IOBW in the rainfall over NEB during austral summer, with EN causing anomalous dryness.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the interannual rainfall variability over SA may also be influenced by the climate variability modes of the tropical Indian Ocean (TIO) [13,14]. One of these modes features a basin-wide sea surface temperature (SST) anomaly pattern (Indian Ocean basin-wide-IOBW), and the other features a zonal dipolar structure between the western TIO and the areas off the coasts of Java and Sumatra Islands (Indian Ocean Dipole-IOD).…”

Section: Introductionmentioning

confidence: 99%

“…One of the remote regions affected by these modes is SA. The IOBW affects the South American climate through the Walker cell and Rossby wave train teleconnection pattern [13,14]. Taschetto and Ambrizzi [13] provided modeling and diagnostic evidence that the warm IOBW event strengthens the EN-related atmospheric circulation and rainfall anomalies over SA and contributes to the persistent dryness over northeastern Brazil (NEB) during austral autumn.…”

Section: Introductionmentioning

confidence: 99%

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El Niño-Southern Oscillation and Indian Ocean Dipole Modes: Their Effects on South American Rainfall during Austral Spring

et al. 2021

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This paper examines the effects of the tropical Pacific Ocean (TPO) and Indian Ocean Dipole (IOD) modes in the interannual variations of austral spring rainfall over South America (SA). The TPO mode refers to the El Niño-Southern Oscillation (ENSO). The isolated effects between IOD and TPO were estimated, events were chosen from the residual TPO (R-TPO) or residual IOD (R-IOD), and the IOD (TPO) effects for the R-TPO (R-IOD) composites were removed from the variables. One relevant result was the nonlinear precipitation response to R-TPO and R-IOD. This feature was accentuated for the R-IOD composites. The positive R-IOD composite showed significant negative precipitation anomalies along equatorial SA east of 55° W and in subtropical western SA, and showed positive anomalies in northwestern SA and central Brazil. The negative R-IOD composite indicated significant positive precipitation anomalies in northwestern Amazon, central–eastern Brazil north of 20° S, and western subtropical SA, and negative anomalies were found in western SA south of 30° S. This nonlinearity was likely due to the distinct atmospheric circulation responses to the anomalous heating sources located in longitudinally distinct regions: the western tropical Indian Ocean and areas neighboring Indonesia. The results obtained in this study might be relevant for climate monitoring and modeling studies.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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El Niño-Southern Oscillation and Indian Ocean Dipole Modes: Their Effects on South American Rainfall during Austral Spring

et al. 2021

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Decadal variability in the austral summer precipitation over the Central Andes: Observations and the empirical‐statistical downscaling model

Sulca

Takahashi

Tacza

et al. 2022

Intl Journal of Climatology

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Interdecadal Pacific Oscillation modulation of ENSO teleconnections in its decaying stages: Relations with Indian Ocean basin‐wide mode and South American precipitation

Souza

Andreoli

Kayano

et al. 2023

Intl Journal of Climatology

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This study examines the Interdecadal Pacific Oscillation (IPO) modulation of the El Niño-Southern Oscillation (ENSO) teleconnections in its decaying stages with the tropical ocean by focusing on the Indian Ocean Basin-Wide (IOBW) mode and the precipitation over South America (SA) in the 1901-2012 period. Composite analyses revealed that the ENSO teleconnections are IPO-modulated due to the differential ENSO decaying speed, which is slower during the positive than negative IPO phase, for both El Niño (EN) and La Niña (LN) cases. Negative precipitation anomalies related to EN persist over northeastern SA until austral winter for the positive IPO phase (POS IPO), while significant opposite sign anomalies occur in this region for the negative IPO phase (NEG IPO). These results are associated with the Walker circulation's reversal during NEG IPO which is, in turn, accompanied by negative IOBW. During the POS IPO, the positive IOBW causes upward movements over there and, by continuity, downward movements over SA. In the NEG IPO, for LN events the wave train originating in the north of Australia propagates toward subtropical SA, which, coupled with the surface circulation, causes dryness in this region. In addition, the rapid decay of LN in the NEG IPO, followed by the emergence of EN, caused changes in the Walker circulation, such that enhanced upward movements occurred over the Pacific and SA region, and downward movements over the Indian Ocean until austral winter. In turn, the slower decay of the LN in the POS IPO maintains strong subsidence over the central Pacific and weak upward motions over western SA. So, the EN (LN) and positive (negative) IOBW during the POS (NEG) IPO prolong the scarcity of precipitation over equatorial (subtropical) SA. Persistent dry periods over these regions during the ENSO decaying stage might have important implications for the seasonal forecasts.

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The Role of the Indian Ocean Basin-Wide and El Niño–Southern Oscillation Modes in Interannual Rainfall Variability over South America during Austral Summer

Cited by 5 publications

References 53 publications

El Niño-Southern Oscillation and Indian Ocean Dipole Modes: Their Effects on South American Rainfall during Austral Spring

El Niño-Southern Oscillation and Indian Ocean Dipole Modes: Their Effects on South American Rainfall during Austral Spring

Decadal variability in the austral summer precipitation over the Central Andes: Observations and the empirical‐statistical downscaling model

Interdecadal Pacific Oscillation modulation of ENSO teleconnections in its decaying stages: Relations with Indian Ocean basin‐wide mode and South American precipitation

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