On the role of the south Pacific subtropical high at the onset of El Niño events

Zou, Youjia; Xi, Xiangying

doi:10.5194/acp-2018-82

Cited by 3 publications

(16 citation statements)

References 22 publications

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“…The circulation of the SPG is strongly influenced by several atmospheric features, such as the South Pacific Anticyclone (SPA; also referred to as the South Pacific Subtropical High; Rodwell et al (2001); Grotjahn (2004); Zou et al (2018); Flores-Aqueveque et al (2020)) andSouth Pacific Convergence Zone (SPCZ) (Takahashi et al, 2007b;Takahashi et al, 2007a). The SPA is a large-scale, quasi-permanent high-pressure system in the mid-latitude eastern Pacific produced by the general circulation of the atmosphere (Rodwell et al, 2001;Grotjahn, 2004;Ancapichún et al, 2015;Flores-Aqueveque et al, 2020).…”

Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

“…Seasonally, the SPA migrates north and south with little impact to the trade winds (Rodwell et al, 2001); however, on longer timescales (e.g. interannual to millennial timescales) a migration can weaken or enhance the southeast trade winds and weaken or enhance the equatorial countercurrent (ECC) (Zou et al, 2018). Changes in trade wind intensity and location can modulate the position of 1) vertical atmospheric convection zones across the equatorial Pacific (e.g.…”

Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

“…Changes in trade wind intensity and location can modulate the position of 1) vertical atmospheric convection zones across the equatorial Pacific (e.g. the Intertropical Convergence Zone and South Pacific Convergence Zone; Takahashi et al (2007b); Flores-Aqueveque et al (2020)) and 2) the equatorial and eastern south Pacific currents (the North and South Equatorial Currents and Humboldt Current; Zou et al (2018)). Variations in trade wind strength associated with the location of the SPA can therefore amplify or suppress precipitation and equatorial ocean circulation across the eastern and equatorial portions of the gyre (Rodwell et al, 2001;Takahashi et al, 2007b;Takahashi et al, 2007a;Ancapichún et al, 2015;Zou et al, 2018).…”

Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

“…the Intertropical Convergence Zone and South Pacific Convergence Zone; Takahashi et al (2007b); Flores-Aqueveque et al (2020)) and 2) the equatorial and eastern south Pacific currents (the North and South Equatorial Currents and Humboldt Current; Zou et al (2018)). Variations in trade wind strength associated with the location of the SPA can therefore amplify or suppress precipitation and equatorial ocean circulation across the eastern and equatorial portions of the gyre (Rodwell et al, 2001;Takahashi et al, 2007b;Takahashi et al, 2007a;Ancapichún et al, 2015;Zou et al, 2018). The influences the SPA has on equatorial Pacific circulation makes the SPA a significant influence on the circulation of the SPG, as well as basin-wide Pacific climate modes which alter ocean-atmospheric circulation patterns, such as the El Niño-Southern Oscillation (Zou et al (2018); see section 1.3.1.5 for more details).…”

Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

“…Variations in trade wind strength associated with the location of the SPA can therefore amplify or suppress precipitation and equatorial ocean circulation across the eastern and equatorial portions of the gyre (Rodwell et al, 2001;Takahashi et al, 2007b;Takahashi et al, 2007a;Ancapichún et al, 2015;Zou et al, 2018). The influences the SPA has on equatorial Pacific circulation makes the SPA a significant influence on the circulation of the SPG, as well as basin-wide Pacific climate modes which alter ocean-atmospheric circulation patterns, such as the El Niño-Southern Oscillation (Zou et al (2018); see section 1.3.1.5 for more details). Ocean and atmospheric circulation in the equatorial SPG is also affected by the South Pacific Convergence Zone (SPCZ) Takahashi et al, 2007b;Takahashi et al, 2007a;.…”

Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

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Southwest Pacific Paleoceanography During the Late Holocene: 3000 years of ocean circulation and marine biogeochemistry reconstructed from New Zealand deep-sea black corals

Hitt¹

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The global climate results from interactions between the ocean and atmosphere. Ocean gyres are perhaps one of the most significant interactions; they regulate temperature, salinity and nutrient flow across the ocean basins. Gyres transport warm, tropical waters to higher latitudes and cold waters to lower latitudes and act as the dominant heat-transport mechanism in the Earth’s climate system. They also influence spatial patterns in marine primary production by distributing nutrients between the equator and poles. However, gyre circulation in the subtropics has been strengthening, leading to marine heat waves, changing biogeochemistry and reducing primary production since the early 1900s. These changes are often interpreted as a consequence of anthropogenic climate change. However, ocean circulation and primary production can exhibit natural variations on a variety of timescales. Could these recent changes be a part of a long-term natural cycle or a product of anthropogenic change? This research aims to reconstruct South Pacific Gyre (SPG) circulation and biogeochemistry using a suite of New Zealand black corals. The primary research goal is determining if there is a precedent for the ocean changes observed over the instrumental period. Black corals are an ideal paleoceanographic archive for this work; they provide high-resolution, multi-millennial records of biogeochemistry and ocean circulation within their skeletons, derived using radiocarbon (14C) and stable isotopes (d13C and d15N). In this thesis, I show that late Holocene SPG strength has been highly variable and the relationship between circulation and biogeochemistry is timescale dependent. The black coral radiocarbon records suggest late Holocene SPG circulation has been controlled by westerly wind strength. Our records show the SPG exhibits natural variability on multi-centennial and millennial timescales that corresponds to the variability within the Southern Annular Mode (SAM) and the El Niño-Southern Oscillation (ENSO). The black coral circulation record shows that the modern gyre circulation is not without precedent over the last 3000 years. The black coral d13C and d15N records show significant variability on multi-decadal to multi-centennial timescales. Multi-centennial variability in black coral d13C and d15N appears to be driven by sea surface temperature (SST), nitrogen fixation rates and wind-driven upwelling and is possibly forced by the mean state of the Southern Oscillation Index and ocean circulation strength. A trend in black coral d13C over the last 1500 years also suggests a shift in phytoplankton community structure towards larger and faster growing phytoplankton. These records also reveal a shift in mean coral d13C and d15N between the 0-2000BP and 2000-3000BP period, the latter corresponding to a period of stronger gyre circulation inferred from the radiocarbon records. This work shows that: 1) New Zealand’s black corals are a promising archive for studying paleoceanography; they can extend instrumental ocean records and fill the gap between traditional southwest Pacific paleoceanographic proxy records (tropical corals, sediment cores); 2) SPG circulation has been highly variable over the last 3000 years; circulation is controlled by atmospheric patterns (e.g. SAM) on multi-centennial to millennial timescales; 3) Gyre circulation is only one of many forcing factors on southwest Pacific primary production and marine biogeochemistry; comparisons between the ∆R, d13C and d15N proxies show that variations in SPG biogeochemical patterns and productivity are likely driven by local dynamics such as phytoplankton community structure, SST, upwelling and gyre circulation. Finally, this research demonstrates the key role that a distributed set of deep-sea coral paleoceanographic reconstructions could play in characterizing the dynamical variability in southwest Pacific Ocean circulation, biogeochemistry and primary production. This information is critical for detecting and attributing past and future anthropogenic impacts on the southwest Pacific Ocean.

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Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

Section: Atmospheric Influences On the South Pacific Gyre Circulationmentioning

confidence: 99%

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Southwest Pacific Paleoceanography During the Late Holocene: 3000 years of ocean circulation and marine biogeochemistry reconstructed from New Zealand deep-sea black corals

Hitt¹

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Southwest Pacific Paleoceanography During the Late Holocene: 3000 years of ocean circulation and marine biogeochemistry reconstructed from New Zealand deep-sea black corals

Hitt¹

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Using the Global Hydrodynamic Model and GRACE Follow-On Data to Access the 2020 Catastrophic Flood in Yangtze River Basin

et al. 2021

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Flooding is one of the most widespread and frequent weather-related hazards that has devastating impacts on the society and ecosystem. Monitoring flooding is a vital issue for water resources management, socioeconomic sustainable development, and maintaining life safety. By integrating multiple precipitation, evapotranspiration, and GRACE-Follow On (GRAFO) terrestrial water storage anomaly (TWSA) datasets, this study uses the water balance principle coupled with the CaMa-Flood hydrodynamic model to access the spatiotemporal discharge variations in the Yangtze River basin during the 2020 catastrophic flood. The results show that: (1) TWSA bias dominates the overall uncertainty in runoff at the basin scale, which is spatially governed by uncertainty in TWSA and precipitation; (2) spatially, a field significance at the 5% level is discovered for the correlations between GRAFO-based runoff and GLDAS results. The GRAFO-derived discharge series has a high correlation coefficient with either in situ observations and hydrological simulations for the Yangtze River basin, at the 0.01 significance level; (3) the GRAFO-derived discharge observes the flood peaks in July and August and the recession process in October 2020. Our developed approach provides an alternative way of monitoring large-scale extreme hydrological events with the latest GRAFO release and CaMa-Flood model.

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On the role of the south Pacific subtropical high at the onset of El Niño events

Abstract: 13Previous studies have suggested that an eastward propagation of the warm pool

Cited by 3 publications

References 22 publications

Southwest Pacific Paleoceanography During the Late Holocene: 3000 years of ocean circulation and marine biogeochemistry reconstructed from New Zealand deep-sea black corals

Southwest Pacific Paleoceanography During the Late Holocene: 3000 years of ocean circulation and marine biogeochemistry reconstructed from New Zealand deep-sea black corals

Southwest Pacific Paleoceanography During the Late Holocene: 3000 years of ocean circulation and marine biogeochemistry reconstructed from New Zealand deep-sea black corals

Using the Global Hydrodynamic Model and GRACE Follow-On Data to Access the 2020 Catastrophic Flood in Yangtze River Basin

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