Numerical Modelling Of Changes Of Temperature And Salt Fields In The Bo Sea Including The Waters Around The Yellow River Delt And The Effects On The Current Field

Ecology in the Bo Sea,which is one of the important objectives of China marine ecological protection in China,is affected by factors,such as,among others,temperature and salinity,the latter,in turns,affecting seawater density and further current field through density baroclinic current.Unfortunately,so far,the variations of temperature,salinity and their effects upon current of the Bo Sea are much less studied.Research on changes in the temperature and salinity and their effects upon current in the sea waters around the Yellow River delta will deepen the understandings of their processes and effects due to such factor as river feedings,weather conditions,and thermal exchanges,reduce errors of current measurements in the ambient waters,provide technical support for accurate temporal and spatial allocating of water resources from the Yellow River estuary to protect and use ecological all resources in the Bo Sea.This paper presents the research results,by using a depth-integrated two-dimensional baroclinic hydrodynamic(HD)model,of the simulations of temperature and salinity and current due to the Yellow River feedings like flow rates and temperature,and salinity(always as zero because of fresh water),weather factors like wind velocity and air pressure,and thermal exchanging factors like relative humidity,solar radiation and other factors,all concurring in the 1984 year.It is found that the simulations agree well with the filed measurement calculation,On this basis,the sensitivity analysis is done to study the effects of the individual factors upon the delta-ambient temperature and salinity and currents.The research results show that:1)Heat exchange is the most significant factor driving the changes in temperature and salinity of the whole Bo Sea.Meanwhile,the Yellow River feeding has a medium-level influence upon the temperature and salinity field in the ambient waters covering 900km~2 in area,40km long in the north and south each,30km wide to the east of the mouth in terms of the salinity difference greater than 0.15%in the summer in the cases due to different flow rates.In contrast,weather factors pose an weak influences on the temperature and salinity.2)The average densities of the Bo Sea are found the largest,about 1023.815kg/m3,from January to March due to temperature and salinity,and the least,about1019.136 kg/m3in August,with the others varying between in the other months.3)The maximum differences in the current velocity and water level with and without baroclinic take places at the Bo Sea Strait,while the Laizhou Bay is least affected.