Nonlinearity of Subtidal Estuarine Circulation in the Pearl River Estuary, China

The Pearl River Estuary (PRE) is a bell-shaped estuary with a narrow deep channel and wide shoals. This unique topographic feature leads to different dynamics of the subtidal estuarine circulation (SEC) in the PRE compared with a narrow and straight estuary. In this study, the nonlinear dynamics of the SEC in the PRE under mean circumstance are analyzed by using a validated 3D numerical model. Model results show that the nonlinear advections reach leading order in the along-channel momentum balance. Modulated by tide, the nonlinear advections show significant temporal variations as they have much larger values during spring tide than that during neap tide. Unlike straight and narrow estuaries, both tidally and cross-sectionally averaged axial and lateral advections play important roles in driving the SEC in the PRE in which the axial advection dominates the nonlinear effect, but the two nonlinear terms balance each other largely resulting in a reduced nonlinear effect. Despite this, the total nonlinear advection is still comparable with other terms, and it acts as the baroclinic pressure to reinforce the SEC, especially during the ebb tide, suggesting a flood–ebb asymmetry of the nonlinear dynamics in the PRE. In addition, diagnostic analyses of the along-channel vorticity budget show that nonlinear advections also make significant contribution to drive the lateral circulation in the PRE as Coriolis and baroclinic pressure terms, indicating complex dynamics of the circulation in the PRE.

Download Full-text

Effects of Wave–Current Interaction on Storm Surge in the Pearl River Estuary: A Case Study of Super Typhoon Mangkhut

Frontiers in Marine Science ◽

10.3389/fmars.2021.692359 ◽

2021 ◽

Vol 8 ◽

Author(s):

Zhifa Luo ◽

Bensheng Huang ◽

Xiaohong Chen ◽

Chao Tan ◽

Jing Qiu ◽

...

Keyword(s):

Storm Surge ◽

Current Model ◽

Spring Tide ◽

River Estuary ◽

Pearl River Estuary ◽

Pearl River ◽

Wave Setup ◽

The Pearl River Estuary ◽

Super Typhoon ◽

The Pearl River

This study explored the effects of interactions between waves and current on storm surge in the Pearl River Estuary (PRE) using a fully coupled wave–current model. The model was validated based on in situ observations during the traverse of super typhoon Mangkhut. The results indicated that the model could reproduce the storm surge and wave setup processes. Numerical experiments showed that simulations of storm surge are minimally affected by wave setup. The wave setup during super typhoon Mangkhut reached up to 0.23 m and contributed to the total near shore storm surge by up to 8%. The simulations of the coupled model showed a better correlation with observations compared to those of an uncoupled model. The storm surge increased with transport upstream in a tidal-dominated outlet, whereas it decreased in a river-dominated outlet. The storm surge and wave setup increased and decreased, respectively, during spring tide as compared to that during a neap tide. The storm surge increased with increasing runoff in the upper river reaches, whereas there was little change in the tidal-dominated lower river reaches. This research emphasizes the importance of integrating the effects of multiple dynamic factors in the forecasting of storm surge and provides a reference for similar studies in other estuaries with multiple outlets and a complex river network.

Download Full-text

Distribution Characteristics and Environmental Impacts of Nutrients in the Dry Season of the Pearl River Estuary in 2016

10.5194/egusphere-egu2020-12108 ◽

2020 ◽

Author(s):

Danna Zeng ◽

Lixia Niu ◽

Qingshu Yang

Keyword(s):

Chlorophyll A ◽

River Discharge ◽

Spring Tide ◽

River Estuary ◽

Pearl River Estuary ◽

Dry Season ◽

Pearl River ◽

The Pearl River Estuary ◽

Significant Difference ◽

The Pearl River

<p>Based on the field efforts in 2016 during a dry season (30 Nov-6 Dec) in the Pearl River Estuary (PRE)&#65292;south China, this study aimed to investigate the tidal changes of phytoplankton variability (in terms of chlorophyll a) and their responses to multiple environmental factors.Time series analysis&#65292;principal component analysis (PCA)&#65292;Pearson correlation analysis, and Delft3D model were carried out. A significant difference was found in the tidal variations of dissolved nutrients, covering both a spring tide and neap tide . Moderate differences in salinity and suspended sediment played different roles in the nitrogen and phosphate. The negative correlations of salinity and nitrogen ecologically implied a stronger diluting-mixing effect than that of phosphate, which has a large impact on the water quality. The adsorption of phosphorus by sediment particles was stronger than that of nitrogen. Nitrogen was mainly contributed by river discharge. DIN was constrained by tide-river dynamics and their mutual increase-decline trend, and a new source was supplemented along the transport from river to sea. The weak correlation between PO<sub>4</sub>&#160;and salinity suggested a different source contribution of the terrestrial emission from coastal cities; the contribution of river discharge was less compared with nitrogen.&#160;Over site, P-limitation&#160;was detected and was more frequently resulted in eutrophication and even bloom events.&#160;Characterizing the relationships among chlorophyll a, nutrients, and hydrological factors enables us to develop effective ecosystem management strategies, and to design studies more focused on ecological health and function.</p>

Download Full-text

Impact of tides and winds on estuarine circulation in the Pearl River Estuary

Continental Shelf Research ◽

10.1016/j.csr.2018.09.004 ◽

2018 ◽

Vol 168 ◽

pp. 68-82 ◽

Cited By ~ 4

Author(s):

Wenfeng Lai ◽

Jiayi Pan ◽

Adam T. Devlin

Keyword(s):

River Estuary ◽

Pearl River Estuary ◽

Estuarine Circulation ◽

Pearl River ◽

The Pearl River Estuary ◽

The Pearl River

Download Full-text

Effects of climate change and fishing on the Pearl River Estuary ecosystem and fisheries

Reviews in Fish Biology and Fisheries ◽

10.1007/s11160-019-09574-y ◽

2019 ◽

Vol 29 (4) ◽

pp. 861-875

Author(s):

Zeyu Zeng ◽

William W. L. Cheung ◽

Shiyu Li ◽

Jiatang Hu ◽

Ying Wang

Keyword(s):

Climate Change ◽

River Estuary ◽

Pearl River Estuary ◽

Pearl River ◽

The Pearl River Estuary ◽

The Pearl River

Download Full-text

The Role of Environmental Factors on the Fishery Catch of the Squid Uroteuthis chinensis in the Pearl River Estuary, China

Journal of Marine Science and Engineering ◽

10.3390/jmse9020131 ◽

2021 ◽

Vol 9 (2) ◽

pp. 131

Author(s):

Dongliang Wang ◽

Lijun Yao ◽

Jing Yu ◽

Pimao Chen

Keyword(s):

River Estuary ◽

Pearl River Estuary ◽

Sea Surface ◽

Spatiotemporal Variability ◽

Pearl River ◽

Coastal Current ◽

Catch Per Unit Effort ◽

Chl A ◽

The Pearl River Estuary ◽

The Pearl River

The Pearl River Estuary (PRE) is one of the major fishing grounds for the squid Uroteuthis chinensis. Taking that into consideration, this study analyzes the environmental effects on the spatiotemporal variability of U. chinensis in the PRE, on the basis of the Generalized Additive Model (GAM) and Clustering Fishing Tactics (CFT), using satellite and in situ observations. Results show that 63.1% of the total variation in U. chinensis Catch Per Unit Effort (CPUE) in the PRE could be explained by looking into outside factors. The most important one was the interaction of sea surface temperature (SST) and month, with a contribution of 26.7%, followed by the interaction effect of depth and month, fishermen’s fishing tactics, sea surface salinity (SSS), chlorophyll a concentration (Chl a), and year, with contributions of 12.8%, 8.5%, 7.7%, 4.0%, and 3.1%, respectively. In summary, U. chinensis in the PRE was mainly distributed over areas with an SST of 22–29 °C, SSS of 32.5–34‰, Chl a of 0–0.3 mg × m−3, and water depth of 40–140 m. The distribution of U. chinensis in the PRE was affected by the western Guangdong coastal current, distribution of marine primary productivity, and variation of habitat conditions. Lower stock of U. chinensis in the PRE was connected with La Niña in 2008.

Download Full-text