Study On The Interaction Between The Yellow River Entrance Runoff And Coastal Waters And Its Application

Estuary and coastal regions are such regions that the interactions between land,sea and river are not only happened frequently in natural changes but also play an important role in the economic construction of society.Yellow River estuary region has unique geographical location and natural environment,and is rich in resources.As the development and construction of the Yellow River delta rises for national strategy,in addition to the chemical energy of economic construction near the ports,ecological fishery and ecological environment construction is also an important part of the development.Plenty of fresh water from the estuary of the Yellow River into the bohai sea formed a sound environment for biological growth and development.But in recent decades,for natural factors such as climate and rainfall and human factors such as increasing demands of industrial and agricultural water and construction,the Yellow River runoff was significantly reduced.The significant changes of Runoff will no doubt influence the temperature and salinity near the river estuary and the whole Bohai Sea.This paper reviews the research progress of runoff of the Yellow River,and done a systematic analysis of the annual and monthly variation rule of the Yellow River based on the measured data from 1950 to 2015.And also expounds the influence on aquaculture environment and architectural environment by the runoff change.Analysis shows that the Yellow River runoff showed a trend of gradual decline.Although the Yellow River realizes no dried-up in ten years and runoff has certain growth than in the 1990 s in recent years under the integrated water regulation by the country,the overall downward trend does not change,and the runoff is and will be prolonged in the status quo of the dry season background for a long time does not change.The significant changes of runoff have influenced the temperature and salinity,influenced the biological low salt environment,accelerated the impact of "salt damage" in the coastal engineering.In this paper,the temperature and salinity fields of Bohai Sea are studied numerically by employing the Regional Ocean Modeling System(ROMS),which responses to the different runoff,different wind field and different topography.The thermohaline distribution characteristics for two typical sections(38.5°N section and Yellow River estuary—North Liaodong Bay section)and the scope and intensity of Yellow River diluted water(low salinity region in Laizhou bay)are discussed.The results show that the vertical distribution of the Bohai sea temperature and salinity is influenced by wind field in winter,but is not sensitive to the runoff and topography.In summer,due to the weaken wind,the scope of warm water on the central shallow ridge has shinks,and the distribution characteristics of salt striped pattern disappeared in the cross section and the salinity becomes higher.When the topography has changed,the characteristics of temperature and salinity distribution in the cross section has also changed.The low salinity region in Laizhou bay which the most significant influence by the runoff,not only has important effect on ecological environment of fishery area,can also affect the sea ice to influence coastal engineering.This study chooses isohaline of 27 psu to show the salinity value of the scope of the core.The results show that the laizhou bay salinity distribution situation is high in east and low in west.With the runoff increase,the two directions extension on the northeast and southeast of the diluted water are well reflected.The salinity of Laizhou bay rapid response to runoff changes,salinity value changes over the runoff.When the topography has changed,the low salinity region has shinks and salinity has increased.There are many factors that can influence the distribution characteristics of temperature and salinity in Bohai sea.The mechanisms which cause this kind of distribution characteristics need further research.This article only analyzed the distribution characteristics of temperature and salinity,and in the later study also need to analyze the flow field characteristic of the bohai sea.In addition,this paper preliminary discusses the influence of the topography change,and the influence mechanism still need further discussion.