The 30–60‐day northward‐propagating intraseasonal oscillation over South China Sea during pre‐monsoon period in a coupled model

Abstract. A field survey from the coastal upwelling zones to the offshore pelagic zones of the northeastern South China Sea (SCS) was conducted during the inter-monsoon period of May 2014 when the region was characterized by prevailing low-nutrient conditions. Comprehensive field measurements were made for not only hydrographic and biogeochemical properties but also phytoplankton growth and microzooplankton grazing rates. We also performed estimations of the vertical turbulent diffusivity and diffusive nutrient fluxes using a Thorpe-scale method and the upwelling nutrient fluxes by Ekman pumping using satellite-derived wind stress curl. Our results suggest that phytoplankton patchiness in the northeastern SCS during the study period could be largely controlled by vertical nutrient fluxes with combined contributions from both turbulent diffusion and curl-driven upwelling. Our results also reveal the generally increasing role of turbulent diffusion but decreasing role of curl-driven upwelling on vertical transport of nutrients from the coastal upwelling zones to the offshore pelagic zones in the northeastern SCS. Elevated nutrient fluxes observed near Dongsha Island were found to support high new production leading to net growth of a diatom-rich phytoplankton community, whereas the low nutrient fluxes near southwest Taiwan resulted in a negative net community growth leading to a decline of a picoplankton-dominant phytoplankton bloom.

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The extended-range forecast of tropical cyclogenesis over the South China Sea based on the intraseasonal oscillation

Meteorology and Atmospheric Physics ◽

10.1007/s00703-021-00830-0 ◽

2021 ◽

Author(s):

Xiaowen Wei ◽

Ying Yang ◽

Liang Chen

Keyword(s):

South China Sea ◽

South China ◽

Intraseasonal Oscillation ◽

The South China Sea ◽

Tropical Cyclogenesis ◽

The South ◽

China Sea ◽

Extended Range

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Physical modulation to the biological productivity in the summer Vietnam upwelling system

Ocean Science ◽

10.5194/os-14-1303-2018 ◽

2018 ◽

Vol 14 (5) ◽

pp. 1303-1320 ◽

Cited By ~ 4

Author(s):

Wenfang Lu ◽

Lie-Yauw Oey ◽

Enhui Liao ◽

Wei Zhuang ◽

Xiao-Hai Yan ◽

...

Keyword(s):

Kinetic Energy ◽

South China Sea ◽

Ocean Circulation ◽

South China ◽

Coastal Upwelling ◽

Coupled Model ◽

Biological Productivity ◽

High Productivity ◽

China Sea ◽

Upwelling System

Abstract. Biological productivity in the summer Vietnam boundary upwelling system in the western South China Sea, as in many coastal upwelling systems, is strongly modulated by wind. However, the role of ocean circulation and mesoscale eddies has not been elucidated. Here, we show a close spatiotemporal covariability between primary production and kinetic energy. High productivity is associated with high kinetic energy, which accounts for ∼15 % of the production variability. Results from a physical–biological coupled model reveal that the elevated kinetic energy is linked to the strength of the current separation from the coast. In the low production scenario, the circulation is not only weaker but also shows weak separation. In the higher production case, the separated current forms an eastward jet into the interior South China Sea, and the associated southern recirculation traps nutrients and favors productivity. When separation is absent, the model shows weakened circulation and eddy activity, with ∼21 % less nitrate inventory and ∼16 % weaker primary productivity.

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