Seasonal changes and driving forces of inflow and outflow through the Bohai Strait. (15th February 2018)

• Record Type: Journal Article
• Authors: Zhang, Zhixin; Qiao, Fangli; Guo, Jingsong; Guo, Binghuo
• Is Part Of: Continental shelf research. Volume 154(2018)
• Page Start: 1
• Page End: 8
• Publication Date: 2018-02-15
• Subjects: Seasonal changes -- Inflow -- Outflow -- Driving force -- Bohai Strait -- Water balance; Continental shelf -- Periodicals; Submarine geology -- Periodicals; 551.41
• DOI: 10.1016/j.csr.2017.12.012
• Languages: English
• ISSNs: 0278-4343

Abstract

Abstract: This work focuses on analyzing seasonal variation of inflow and outflow through the Bohai Strait that greatly affect the marine environment in the Bohai Sea, using observational data including sea bed mounted acoustic Doppler current profiler currents, CTD salinity data on deck, sea level anomalies of coastal tide gauge stations, and climatological monthly sea level anomalies from Archiving, Validation and Interpretation of Satellite Oceanographic data. Our results show three patterns of outflow and inflow through the Bohai Strait. The first is such that outflow and inflow occur respectively in the southern and northern parts of the strait, as in the traditional understanding. Our results suggest that this pattern occurs only in autumn and winter. Beginning in late September, Ekman currents driven by the northwesterly monsoon carry Bohai Sea water that piles up in the southern part of that sea and then exits eastward to the Yellow Sea. In this process, the pressure and current fields are continuously adjusted, until a quasi balance state between wind stress, Coriolis force and pressure gradient force is reached in winter. Inflow with a compensating property through the northern channel is close to the outflow through the southern channel in winter. The second pattern is a single inflow in spring, and the current and pressure fields are in adjustment. In early spring, the northwesterly monsoon ceases, Yellow Sea water enters the Bohai Sea under the pressure gradient force. With southeasterly monsoon establishment and strengthening, northern Yellow Sea water continually flows into the Bohai Sea and causes sea level rise northward. In the third pattern, outflow is much greater than inflow in summer. The currents run eastward in the central Bohai Sea and then enter the northern Yellow Sea through the northern channel and upper layer of the southern channel, while a westward current with a compensating property enters via the lower layer of the southern channel. Larger net transport is through the Bohai Strait to the northern Yellow Sea, which is related to strong precipitation and runoff into the Bohai Sea. Highlights: This work is mainly based on one-month continuous current observations in the Bohai strait, that is never before. The patterns of inflow and outflow through Bohai Strait in various seasons are different from the traditional cognition. The features and driving forces of the inflow and outflow in four seasons are diverse.