Modeling the impact of river discharge and wind on the hypoxia off Yangtze Estuary
The phenomenon of low dissolved oxygen (known as hypoxia) in a coastal ocean system is closely related to a combination of anthropogenic and natural factors. Marine hypoxia occurs in the Yangtze Estuary, China, with high frequency and long persistence. It is related primarily to organic and nutrient...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-12-01
|
| Series: | Natural Hazards and Earth System Sciences |
| Online Access: | http://www.nat-hazards-earth-syst-sci.net/16/2559/2016/nhess-16-2559-2016.pdf |
| Summary: | The phenomenon of low dissolved oxygen (known as hypoxia) in a coastal ocean
system is closely related to a combination of anthropogenic and natural
factors. Marine hypoxia occurs in the Yangtze Estuary, China, with high
frequency and long persistence. It is related primarily to
organic and nutrient enrichment influenced by river discharges and physical
factors, such as water mixing. In this paper, a three-dimensional
hydrodynamic model was coupled to a biological model to simulate and analyze
the ecological system of the East China Sea. By comparing with the
observation data, the model results can reasonably capture the physical and
biochemical dynamics of the Yangtze Estuary. In addition, the sensitive
experiments were also used to examine the role of physical forcing (river
discharge, wind speed, wind direction) in controlling hypoxia in waters
adjacent to the Yangtze Estuary. The results showed that the wind field and
river discharge have significant impact on the hypoxia off the Yangtze
Estuary. The seasonal cycle of hypoxia was relatively insensitive to synoptic
variability in the river discharge, but integrated hypoxic areas were
sensitive to the whole magnitude of river discharge. Increasing the river
discharge was shown to increase hypoxic areas, while decreasing the river
discharge tended to decrease hypoxic areas. The variations of wind speed
and direction had a great impact on the integrated hypoxic areas. |
|---|---|
| ISSN: | 1561-8633 1684-9981 |