scholarly journals Tropical origins of North and South Pacific decadal variability

2009 ◽  
Vol 36 (19) ◽  
Author(s):  
Jeremy D. Shakun ◽  
Jeffrey Shaman
Keyword(s):  
Decadal Variability ◽  
South Pacific ◽  
Pacific Decadal Variability ◽  
North And South

Tropical Pacific Decadal Variability and ENSO Precursor in CMIP5 Models

2021 ◽  
Vol 34 (3) ◽  
pp. 1023-1045
Author(s):  
Yingying Zhao ◽  
Emanuele Di Lorenzo ◽  
Daoxun Sun ◽  
Samantha Stevenson
Keyword(s):  
Decadal Variability ◽  
South Pacific ◽  
Tropical Pacific ◽  
Cmip5 Models ◽  
The North ◽  
Enso Teleconnections ◽  
Pacific Decadal Variability ◽  
Basin Scale ◽  
The Tropics ◽  
North And South

AbstractObservational analyses suggest that a significant fraction of the tropical Pacific decadal variability (TPDV) (~60%–70%) is energized by the combined action of extratropical precursors of El Niño–Southern Oscillation (ENSO) originating from the North and South Pacific. Specifically, the growth and decay of the basin-scale TPDV pattern (time scale = ~1.5–2 years) is linked to the following sequence: ENSO precursors (extratropics, growth phase) → ENSO (tropics, peak phase) → ENSO successors (extratropics, decay phase) resulting from ENSO teleconnections. This sequence of teleconnections is an important physical basis for Pacific climate predictability. Here we examine the TPDV and its connection to extratropical dynamics in 20 models from phase 5 of the Coupled Model Intercomparison Project (CMIP). We find that most models (~80%) can simulate the observed spatial pattern (R > 0.6) and frequency characteristics of the TPDV. In 12 models, more than 65% of the basinwide Pacific decadal variability (PDV) originates from TPDV, which is comparable with observations (~70%). However, despite reproducing the basic spatial and temporal statistics, models underestimate the influence of the North and South Pacific ENSO precursors to the TPDV, and most of the models’ TPDV originates in the tropics. Only 35%–40% of the models reproduce the observed extratropical ENSO precursor patterns (R > 0.5). Models with a better representation of the ENSO precursors show 1) better basin-scale signatures of TPDV and 2) stronger ENSO teleconnections from/to the tropics that are consistent with observations. These results suggest that better representation of ENSO precursor dynamics in CMIP may lead to improved Pacific decadal variability dynamics and predictability.

scholarly journals Role of Stochastic Atmospheric Forcing from the South and North Pacific in Tropical Pacific Decadal Variability

2019 ◽  
Vol 32 (13) ◽  
pp. 4013-4038 ◽  
Author(s):  
Tianyi Sun ◽  
Yuko M. Okumura
Keyword(s):  
North Pacific ◽  
Large Scale ◽  
Decadal Variability ◽  
South Pacific ◽  
Tropical Pacific ◽  
Ocean Dynamics ◽  
The South ◽  
Pacific Decadal Variability ◽  
Sst Anomalies ◽  
The Tropical Pacific

Abstract Stochastic variability of internal atmospheric modes, known as teleconnection patterns, drives large-scale patterns of low-frequency SST variability in the extratropics. To investigate how the decadal component of this stochastically driven variability in the South and North Pacific affects the tropical Pacific and contributes to the observed basinwide pattern of decadal variability, a suite of climate model experiments was conducted. In these experiments, the models are forced with constant surface heat flux anomalies associated with the decadal component of the dominant atmospheric modes, particularly the Pacific–South American (PSA) and North Pacific Oscillation (NPO) patterns. Both the PSA and NPO modes induce basinwide SST anomalies in the tropical Pacific and beyond that resemble the observed interdecadal Pacific oscillation. The subtropical SST anomalies forced by the PSA and NPO modes propagate to the equatorial Pacific mainly through the wind–evaporation–SST feedback. This atmospheric bridge is stronger from the South Pacific than the North Pacific due to the northward displacement of the intertropical convergence zone and the associated northward advection of momentum anomalies. The equatorial ocean dynamics is also more strongly influenced by atmospheric circulation changes induced by the PSA mode than the NPO mode. In the PSA experiment, persistent and zonally coherent wind stress curl anomalies over the South Pacific affect the zonal mean depth of the equatorial thermocline and weaken the equatorial SST anomalies resulting from the atmospheric bridge. This oceanic adjustment serves as a delayed negative feedback and may be important for setting the time scales of tropical Pacific decadal variability.

Influence of the South Pacific decadal variability on Southeast China rainfall during boreal autumn

2017 ◽  
Vol 38 ◽  
pp. e209-e223
Author(s):  
Gang Li ◽  
Jiepeng Chen ◽  
Xin Wang ◽  
Yanke Tan
Keyword(s):  
Decadal Variability ◽  
South Pacific ◽  
The South ◽  
Southeast China ◽  
Pacific Decadal Variability

Freshwater and Heat Changes in the North and South Pacific Oceans between the 1960s and 1985–94

2001 ◽  
Vol 14 (7) ◽  
pp. 1613-1633 ◽  
Author(s):  
Annie P. S. Wong ◽  
Nathaniel L. Bindoff ◽  
John A. Church
Keyword(s):  
South Pacific ◽  
The North ◽  
The 1960S ◽  
North And South

The relationship between the El Niño Southern Oscillation and Australian monsoon rainfall on decadal time-scales

2021 ◽  
Author(s):  
Hanna Heidemann ◽  
Joachim Ribbe ◽  
Benjamin J. Henley ◽  
Tim Cowan ◽  
Christa Pudmenzky ◽  
...  
Keyword(s):  
Monsoon Rainfall ◽  
Decadal Variability ◽  
Southern Oscillation ◽  
Eastern Pacific ◽  
Central Pacific ◽  
Australian Monsoon ◽  
Enso Events ◽  
Pacific Decadal Variability ◽  
Prediction Systems ◽  
Different Response

<p>This research analyses the observed relationship between eastern and central Pacific El Niño Southern Oscillation (ENSO) events and Australian monsoon rainfall (AUMR) on a decadal timescale during the December to March monsoon months. To assess the decadal influence of the different flavours of ENSO on the AUMR, we focus on the phases of the Interdecadal Pacific Oscillation (IPO) over the period 1920 to 2020.  The AUMR is characterized by substantial decadal variability, which appears to be linked to the positive and negative phases of the IPO. During the past two historical negative IPO phases, significant correlations have been observed between central Pacific sea surface temperature (SST) anomalies and AUMR over both the northeast and northwest of Australia. This central Pacific SST-AUMR relationship has strengthened from the first negative IPO phase (mid-1940s to the mid-1970s) to the second (late 1990s to mid-2010s), while the eastern Pacific SST-AUMR influence has weakened. Composite rainfall anomalies over Australia reveal a different response of AUMR to central Pacific El Niño/La Niña and eastern Pacific La Niña events during positive IPO and negative IPO phases. This research clearly shows that ENSO's influence on AUMR is modulated by Pacific decadal variability, however this teleconnection, in itself, can change between similar decadal Pacific states.  Going forward, as decadal prediction systems improve and become more mainstream, the IPO phase could be used as a potential source for decadal predictability of the tendency of AUMR.  </p>

C1-C4hydrocarbons in the North and South Pacific

Tellus ◽  
1974 ◽  
Vol 26 (1-2) ◽  
pp. 71-77 ◽  
Author(s):  
R. A. LAMONTAGNE ◽  
J. W. SWINNERTON ◽  
V. J. LINNENBOM
Keyword(s):  
South Pacific ◽  
The North ◽  
North And South

scholarly journals Formation Mechanism of Barrier Layer in the Subtropical Pacific

2015 ◽  
Vol 45 (11) ◽  
pp. 2790-2805 ◽  
Author(s):  
Shota Katsura ◽  
Eitarou Oka ◽  
Kanako Sato
Keyword(s):  
Formation Mechanism ◽  
Barrier Layer ◽  
Seasonal Variations ◽  
Southern Oscillation ◽  
World Ocean ◽  
South Pacific ◽  
Sea Surface ◽  
Layer Depth ◽  
Isothermal Layer ◽  
North And South

AbstractSeasonal and interannual variations of the barrier layer (BL) and its formation mechanism in the subtropical North and South Pacific were investigated by using raw and gridded Argo profiling float data and various surface flux data in 2003–12 and hydrographic section data from the World Ocean Circulation Experiment Hydrographic Programme. BLs detected by raw Argo profiles, which existed within the sea surface salinity (SSS) front located on the equator side of SSS maxima, were thickest and most frequent in winter and had a temporal scale shorter than 10 days, indicating their transient nature. Surface and subsurface processes for the BL formation suggested by previous studies were evaluated. Poleward Ekman advection of fresher water was dominant as the surface freshening process but cannot explain the observed seasonal variations of the BL. Subsurface equatorward intrusion of high-salinity tropical water was too deep to produce salinity stratification within isothermal layers. These results strongly suggest that BLs in the subtropical Pacific are formed mainly through tilting of the SSS front due to the poleward Ekman flow near the sea surface and the equatorward geostrophic flow in the subsurface. This idea is supported by the dominant contribution of the meridional SSS gradient to the meridional sea surface density gradient within the SSS front and the correspondence between the seasonal variations of the BL and isothermal layer depth. On an interannual time scale, the winter BL thickness in the North and South Pacific was related to the Pacific decadal oscillation and the El Niño–Southern Oscillation, respectively, through the intensity of trade winds controlling isothermal layer depth.

scholarly journals Drivers of recent North Pacific decadal variability: the role of aerosol forcing

2021 ◽  
Author(s):  
A. J. Dittus ◽  
E. Hawkins ◽  
J. I. Robson ◽  
D. M. Smith ◽  
L. J. Wilcox
Keyword(s):  
North Pacific ◽  
Decadal Variability ◽  
Aerosol Forcing ◽  
Pacific Decadal Variability
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