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

Souza, Itamara Parente de; Andreoli, Rita V.; Kayano, Mary Toshie; Cerón, Wilmar Loaiza; Souza, R. A. F. D.; Roy, Indrani

doi:10.1002/joc.8028

Cited by 3 publications

(1 citation statement)

References 37 publications

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“…The connection between ENSO and the low-frequency modulation of the IPO has been explored in studies [29][30][31][32][33][34], demonstrating that the warm (positive)/cool (negative) phase of the IPO can strengthen El Niño events and weaken La Niña events. Similarly, [35] associated the cold (negative) phase of the IPO with reduced rainfall on the northern coast of Chile (18°S-30°S).…”

Section: Interdecadal Pacific Oscillation (Ipo)mentioning

confidence: 99%

Extreme Droughts and Their Relationship with the Interdecadal Pacific Oscillation in the Peruvian Altiplano Region over the Last 100 Years

Angulo,

Pereira Filho

2023

Atmosphere

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The Peruvian Altiplano Region (RAP) is a high plateau area surrounded by the Western and Eastern Andes mountain ranges. This study examines the relationship between extreme droughts in the region and the interdecadal Pacific Oscillation (IPO) over the past century. Previous research has shown that precipitation patterns in the region follow a decreasing trend, with systematic increases in precipitation on the western slope and decreases in the eastern, southern, and central parts. The temporal and spatial variability of precipitation in the Altiplano region is influenced by the easterly moisture flux and the interaction between the El Niño Southern Oscillation (ENSO) and below-average values. The study utilizes water level data for Lake Titicaca and IPO data from 1914 to 2015. The analysis employs wavelet transform and empirical orthogonal function (EOF) techniques to identify the relationship between water levels and IPO. The results indicate multidecadal variability in water levels associated with El Niño/La Niña events and the IPO. The negative phase of the IPO aligns with extreme drought periods, suggesting a connection between the IPO climate index and drought events. The EOF analysis shows a moderate positive correlation between water levels and IPO. The findings highlight the importance of considering IPO and its interaction with ENSO in understanding drought patterns in the Altiplano region. However, other atmospheric conditions also influence precipitation in the region. The study contributes to a better understanding of the factors affecting water levels and droughts in the Peruvian Altiplano, with implications for water resource management in the region.

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Section: Interdecadal Pacific Oscillation (Ipo)mentioning

confidence: 99%

Extreme Droughts and Their Relationship with the Interdecadal Pacific Oscillation in the Peruvian Altiplano Region over the Last 100 Years

Angulo,

Pereira Filho

2023

Atmosphere

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The Cyclic and Episodic Transition of Strong El Niño and Implications for South American Precipitation During Their Peak and Decay Stages

Mamani,

Andreoli,

de Souza

et al. 2024

Intl Journal of Climatology

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The mechanisms associated with the transitions of strong El Niño (EN) events and their implications for the South American precipitation were investigated for the 1950–2023 period. Strong EN events exhibit cyclic or episodic characteristics in their transitions. Cyclic EN events are both preceded and followed by La Niña (LN) conditions, whereas episodic EN events are preceded by neutral conditions, with a more uncertain transition following. For cyclic EN, tropical Pacific mechanisms initiates and peak warming in the eastern tropical Pacific from austral winter to early summer. In contrast, for episodic EN, coupled subtropical and tropical Pacific mechanisms, respectively, initiate and peak warming in the central tropical Pacific from autumn to late summer. The Pacific Decadal Oscillation (PDO) mean state modulates EN's decay stage. During the +PDO mean state, cyclones in the eastern subtropical Pacific of both hemispheres sustain the warming of episodic EN, whereas during the −PDO mean state, anticyclones in the eastern subtropical Pacific accelerate the decay of cyclic EN, favouring its transition to an LN. These mechanisms explain why episodic EN initiates earlier, peaks later, is more intense and decays more slowly than cyclic EN. During an episodic EN summer, the strengthened atmospheric circulation maintains the Atlantic Intertropical Convergence Zone (ITCZ) north of the equator, causing persistent negative precipitation anomalies in north–northeastern South America (SA) until the following winter, while positive precipitation anomalies in southeastern SA are driven by south–southeastward moisture transport from equatorial Atlantic. Conversely, during a cyclic EN summer, negative (positive) precipitation anomalies impact north–northwestern (southeastern) SA; however, the anomalous atmospheric circulation and precipitation in SA quickly return to normal conditions in the autumn, and positive precipitation anomalies appear in northern SA in the following winter. Understanding these mechanisms is crucial for predicting EN's future changes and, consequently, their potential socio‐economic impacts globally.

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Extreme Droughts and Their Relationship with the Interdecadal Pacific Oscillation over the Peruvian Altiplano Region during the Last 100 Years

Angulo¹,

Filho²

2023

Preprint

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Empirical Orthogonal Functions (EOF) analysis between the anomalies of Lake Titicaca water levels (WLs) and the Pacific Interdecadal Oscillation (IPO) reveals a correlation coefficient of 0.71 between the WLs and the principal component (PC1). These findings demonstrate the high accuracy of the IPO in representing the positive and negative phases of the water levels. By utilizing wavelet functions, we identified multi-decadal variability with periods ranging between 20 and 30 years. The statistical techniques employed indicate a relationship between IPO and ENSO; however, they operate on different timescales of climate variability. The IPO exhibits longer-term variability, typically spanning 20-30 years, while ENSO events occur on average every 2-7 years. Nevertheless, the IPO has the ability to modulate the strength and frequency of El Niño and La Niña events, and vice versa. During the positive phase of the IPO, there is a tendency for more frequent and intense El Niño events, accompanied by fewer La Niña events. This can be attributed to warmer sea surface temperatures in the central and eastern Pacific, which create favorable conditions for El Niño development. Conversely, during the negative phase of the IPO, there is a tendency for more frequent and intense La Niña events, with fewer occurrences of El Niño events, due to cooler sea surface temperatures in the central and eastern Pacific.

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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

Cited by 3 publications

References 37 publications

Extreme Droughts and Their Relationship with the Interdecadal Pacific Oscillation in the Peruvian Altiplano Region over the Last 100 Years

Extreme Droughts and Their Relationship with the Interdecadal Pacific Oscillation in the Peruvian Altiplano Region over the Last 100 Years

The Cyclic and Episodic Transition of Strong El Niño and Implications for South American Precipitation During Their Peak and Decay Stages

Extreme Droughts and Their Relationship with the Interdecadal Pacific Oscillation over the Peruvian Altiplano Region during the Last 100 Years

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