Spatiotemporal Development and Dissipation of Hypoxia Induced by Variable Wind-Driven Shelf Circulation off the Pearl River Estuary: Observational and Modeling Studies

Li，Dou1; Gan，Jianping1; Hui，Chiwing1; Yu，Liuqian1; Liu，Zhiqiang1,2; Lu，Zhongming1; Kao，Shuh ji3; Dai，Minhan3

2021-02-01

10.1029/2020JC016700

JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS   影响因子和分区

2169-9275

2169-9291

Observations reveal the high spatiotemporal variability of the hypoxia in the western and eastern coastal transition zones (WCTZ and ECTZ) off the Pearl River Estuary (PRE). We utilized data from cruise observations, buoy mooring, and a three-dimensional model based on ROMS to investigate the hypoxia variability response to the typical synoptic variation of the summer monsoon, i.e., from prevailing upwelling-favorable wind (UFW), the ensuing episodic upwelling relaxation (URW), downwelling (DFW), to downwelling relaxation wind (DRW). During the UFW, we found that the northeastward shelf current converges with nutrient-rich river plume, forms strong stratification, and provides hubs for depositing detritus for hypoxia to develop in the CTZ. The ensuing URW and DFW forcing alters the transport to advect the plume and detritus westward, weakens vertical mixing, and enhances hypoxia in the WCTZ. Correspondingly, opposite conditions occur in the ECTZ as the plume veers westward during the URW and DFW. Contrarily, the weakening westward transport during the DRW forcing restores the biophysical conditions to their states when there is an UFW event. We found that varying wind-driven circulation interacts with the plume to jointly regulate the transport of nutrient and detritus, water vertical mixing, and residence time, and, thus, the hypoxia variability in the CTZ. The variability of hypoxia in the CTZ is less controlled by the river discharges once biogeochemical conditions become saturated. Our study illustrates the biophysical control of hypoxia variability that is frequently observed in estuaries and coastal oceans.

coupled physical-biogeochemical processes eutrophication and hypoxia spatiotemporal variability variable wind-driven shelf circulation and transport

SCI

英语

其他

Theme-based Research Scheme of the Hong Kong Research Grants Council[T21-602/16-R]

Oceanography

Oceanography

WOS:000624429800056

AMER GEOPHYSICAL UNION

GEOSCIENCES

2-s2.0-85101747964

Scopus

1.Department of Ocean Science,Department of Mathematics and Center for Ocean Research in Hong Kong and Macau,Hong Kong University of Science and Technology,Hong Kong
2.Department of Ocean Science and Engineering,Southern University of Science and Technology,Shenzhen,China
3.State Key Lab of Marine Environmental Science,Xiamen University,Xiamen,China

Li，Dou,Gan，Jianping,Hui，Chiwing,et al. Spatiotemporal Development and Dissipation of Hypoxia Induced by Variable Wind-Driven Shelf Circulation off the Pearl River Estuary: Observational and Modeling Studies[J]. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,2021,126(2).

Li，Dou.,Gan，Jianping.,Hui，Chiwing.,Yu，Liuqian.,Liu，Zhiqiang.,...&Dai，Minhan.(2021).Spatiotemporal Development and Dissipation of Hypoxia Induced by Variable Wind-Driven Shelf Circulation off the Pearl River Estuary: Observational and Modeling Studies.JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,126(2).

Li，Dou,et al."Spatiotemporal Development and Dissipation of Hypoxia Induced by Variable Wind-Driven Shelf Circulation off the Pearl River Estuary: Observational and Modeling Studies".JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 126.2(2021).