Optimization And Application Of Key Parameters In A Coupled ROMS-CoSiNE Model Of The Bohai And Yellow Seas

Ocean ecological modelling is one of the most important methods to study marine ecosystems.As the development of marine ecosystem models,the number of biological parameters increases,which consequently causes determination of these parameters to become a bottleneck in ecosystem modeling.Intrinsic regional characteristics of the ecosystem require spatial variability of biological parameters.To explore spatial differences of the key parameters and optimize them,a well behaved highly resolved physical-biological coupled ROMS-CoSiNE model for the Bohai and Yellow seas is established.Sensitivity analysis of thirteen biological parameters indicates that significant differences in sensitivity exist between the south center Yellow Sea?YS?and the Bohai Sea?BS?as well as the coastal areas.The most sensitive parameter in the BS is the initial slope of the P-I curve,followed by the half saturation constant for zooplankton grazing and the maximum grazing rate of zooplankton.For the south Yellow Sea?YS?,the most sensitive parameters are the maximum grazing rate of zooplankton,the death rate of phytoplankton and the initial slope of the P-I curve.Overall,key parameters of the Bohai and Yellow seas are the initial slope of the P-I curve,maximum grazing rate of zooplankton and the death rate of phytoplankton.Besides,based on the sensitivity distributions and phytoplankton biomass budget,it is concluded that the low transparency in the BS and higher transparency in the YS are mainly responsible for the spatial differences of sensitivity relative to the initial slope of the P-I curve.Spatial differences of sensitivity relative to the maximum specific growth rate of zooplankton and the death rate of phytoplankton,are influenced by the differences of the phytoplankton amount between the BS and the YS,and related to high nonlinearity in the ecosystem.Furthermore,to calibrate the three key parameters,parameter optimization experiments of single parameter and coupled parameters have been conducted in three different areas including the Bohai Sea,the north Yellow Sea and the south Yellow Sea.As for each area,model behaved the best in the BS when the initial slope of P-I curve is 0.02 day^-1(Wm^-2)^-1 and the grazing rate of microzooplankton and mesozooplankton are 1.3 day^-1 and 0.25 day^-1 severally,and the optimal parameters of the north Yellow Sea and the south Yellow Sea are 0.035 day^-1(Wm^-2)^-11 and 1.7/0.45 day^-1 and 0.035day^-1(Wm^-2)^-1 and 1.6/0.4 day^-1 respectively.