Impacts of Wind and Current on the Interannual Variation of the Summertime Upwelling Off Southern Vietnam in the South China Sea

Ngo, Mai-Han; Hsin, Yi-Chia

doi:10.1029/2020jc016892

Cited by 18 publications

(26 citation statements)

References 69 publications

(170 reference statements)

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“…It is driven at the first order by atmospheric forcing, namely Ekman transport and pumping induced by the southwest monsoon wind (Xie et al, 2003). It is moreover reinforced by the eastward jet that enhances the offshore advection of coastal water (Dippner et al, 2007a) and by the combination of wind-induced Ekman pumping and positive surface current vorticity associated with cyclonic eddies in the offshore area (Da et al, 2019;Ngo and Hsin, 2021). These studies showed that upwelling develops over several areas.…”

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confidence: 87%

“…Previous field campaigns (Dippner et al, 2007a;Bombar et al, 2010;Loick-Wilde et al, 2017), satellite observations (Xie et al, 2003;Kuo et al, 2004;Ngo and Hsin, 2021), and modeling studies (Li et al, 2014;Da et al, 2019) showed that the SVU intensity strongly varies from one year to another. This interannual variability depends in particular on the intensity of the summer monsoon southwest wind and on ENSO (El Niño-Southern Oscillation) but also on crossequatorial winds (Xian et al, 2019) and decadal climate variability (Wang and Wu, 2020).…”

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confidence: 98%

“…The offshore upwelling (named OFU hereafter) develops over a large offshore region, in the area of cyclonic circulation north of the eastward jet. Two studies moreover showed that upwelling sometimes develops along the northern part of the Vietnamese coast (named NCU hereafter), from 11 to 15 • N. Da et al (2019) revealed from Advanced Very High Resolution Radiometer (AVHRR) SST (sea surface temperature) satellite data and from a 1/12 • simulation that upwelling developed during summer 1998 in this area, and Ngo and Hsin (2021) studied the interannual variability of the NCU using gridded satellite data.…”

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confidence: 99%

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The role of wind, mesoscale dynamics, and coastal circulation in the interannual variability of the South Vietnam Upwelling, South China Sea – answers from a high-resolution ocean model

et al. 2022

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Abstract. The South Vietnam Upwelling (SVU) develops in the South China Sea (SCS) under the influence of southwest monsoon winds. To study the role of small spatiotemporal scales on the SVU functioning and variability, a simulation was performed over 2009–2018 with a high-resolution configuration (1 km at the coast) of the SYMPHONIE model implemented over the western region of the SCS. Its capability to represent ocean dynamics and water masses from daily to interannual scales and from coastal to regional areas is quantitatively demonstrated by comparison with available satellite data and four in situ datasets. The SVU interannual variability is examined for the three development areas already known: the southern (SCU) and northern (NCU) coastal upwelling areas and the offshore upwelling area (OFU). Our high-resolution model, together with in situ observations and high-resolution satellite data, moreover shows for the first time that upwelling develops over the Sunda Shelf off the Mekong Delta (MKU). Our results confirm for the SCU and OFU and show for the MKU the role of the mean summer intensity of wind and cyclonic circulation over the offshore area in driving the interannual variability of the upwelling intensity. They further reveal that other factors contribute to SCU and OFU variability. First, the intraseasonal wind chronology strengthens (in the case of regular wind peaks occurring throughout the summer for SCU or of stronger winds in July–August for OFU) or weakens (in the case of intermittent wind peaks for SCU) the summer average upwelling intensity. Second, the mesoscale circulation influences this intensity (multiple dipole eddies and associated eastward jets developing along the coast enhance the SCU intensity). The NCU interannual variability is less driven by the regional-scale wind (with weaker monsoon favoring stronger NCU) and more by the mesoscale circulation in the NCU area: the NCU is prevented (favored) when alongshore (offshore) currents prevail.

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confidence: 87%

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confidence: 98%

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confidence: 99%

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The role of wind, mesoscale dynamics, and coastal circulation in the interannual variability of the South Vietnam Upwelling, South China Sea – answers from a high-resolution ocean model

et al. 2022

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“…The Asian monsoon is the most important factor influencing ocean circulation in the SCS (Wang et al, 2020). In summer, the SCS is affected by the southwest monsoon, which induces offshore Ekman transport and brings upwelling near the coast of southeast Vietnam (Xie et al, 2003(Xie et al, , 2007Li et al, 2014;Da et al, 2019;Ngo and Hsin, 2021). Additionally, the wind curl force of the southwest wind jet causes the double gyre circulation to form in the SCS with a northern cyclonic gyre and a southern anticyclonic gyre (Kuo et al, 2000;Metzger, 2003;Da et al, 2019;Ngo and Hsin, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…In summer, the SCS is affected by the southwest monsoon, which induces offshore Ekman transport and brings upwelling near the coast of southeast Vietnam (Xie et al, 2003(Xie et al, , 2007Li et al, 2014;Da et al, 2019;Ngo and Hsin, 2021). Additionally, the wind curl force of the southwest wind jet causes the double gyre circulation to form in the SCS with a northern cyclonic gyre and a southern anticyclonic gyre (Kuo et al, 2000;Metzger, 2003;Da et al, 2019;Ngo and Hsin, 2021). The cold coastal water is transported to the open SCS under the combined influence of the southwest wind jet and southern anticyclonic gyre, forming a clear cold filament in the sea surface temperature (Li et al, 2017;Huang et al, 2020;Sun and Lan, 2021).…”

Section: Introductionmentioning

confidence: 99%

Controls of Wind-Driven Jet on the Distribution of Pelagic Cnidarians in the Midwestern South China Sea

Chen

et al. 2021

Front. Mar. Sci.

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The coastal water transported by the combined action of southwest wind jet and anticyclonic eddy substantially influences the biological processes in the midwestern South China Sea. However, how the wind-driven jet affects the zooplankton community remains unclear. In this study, the species number, abundance, and vertical distribution of medusae were investigated in the wind-driven jet (WJR) and non-wind-driven jet regions (NWJR). The low-salinity and nutrient-rich coastal water substantially influenced species composition, abundance, and vertical distribution of medusae in the WJR. The species number of the meroplanktonic hydromedusae in the WJR was approximately twice that in the NWJR due to the horizontal transport of wind-driven jets. The abundances of holoplanktonic hydromedusae in WJR were 38.2 ± 9.3 ind⋅m–3, which were thrice of that in the NWJR regions, caused by the abundant diet in the WJR. Additionally, only the abundance of medusae above the thermocline was affected by the coastal water in WJR, while these showed no significant difference below the thermocline between the WJR and the NWJR. Generalized additive model analyses suggested that the diet was the most important factor affecting the abundance of the holoplanktonic hydromedusae and siphonophore, whereas meroplanktonic hydromedusae were influenced by the combination of temperature, salinity, and diet.

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Summer surface warming driven by the strong El Niño in the South China Sea

Bi,

Liu,

Chen

2023

Clim Dyn

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The interannual variability of sea surface temperature (SST) in the South China Sea (SCS) exhibits two peaks around January and August in the subsequent year of the El Niño. We show that the second basinscale summer SST warming feature peaked in August [+1] is only distinct after strong El Niño events, not regular El Niño events. The upper ocean heat budget analysis demonstrates that the abnormal Ekman advection (Eka) dominants the second warming features during the whole developing stages from June [+1] to August [+1], while the abnormal geostrophic advection (Goa) leads to the warm tendency in June [+1], by reducing the Vietnam coastal upwelling. The local dynamical effects of abnormal Eka and Goa in the SCS are attributed to the advanced abnormal easterly wind breakout in the western Paci c, coincided with the development of West North Paci c anomalous anticyclone (WNPAC) in response to strong El Niño. Our results suggest that the second warming features of SCS SST during the next summer are the footprints of strong El Niño events via the establishment of the WNPAC, which is tightly related to Indo-Paci c remote processes.

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Impacts of Wind and Current on the Interannual Variation of the Summertime Upwelling Off Southern Vietnam in the South China Sea

Abstract: The South China Sea (SCS) is the largest marginal sea of the western Pacific Ocean. Adjoining the western Pacific Ocean and the eastern Indian Ocean, the atmospheric and the oceanic dynamical processes of the SCS are strongly influenced by climate variability of the two oceans (

Cited by 18 publications

References 69 publications

The role of wind, mesoscale dynamics, and coastal circulation in the interannual variability of the South Vietnam Upwelling, South China Sea – answers from a high-resolution ocean model

The role of wind, mesoscale dynamics, and coastal circulation in the interannual variability of the South Vietnam Upwelling, South China Sea – answers from a high-resolution ocean model

Controls of Wind-Driven Jet on the Distribution of Pelagic Cnidarians in the Midwestern South China Sea

Summer surface warming driven by the strong El Niño in the South China Sea

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