Using a gridded array for real-time geostrophic oceanography(Argo)program float dataset,the features of upperocean salinity stratification in the tropical Pacific Ocean are studied.The salinity component of the square...Using a gridded array for real-time geostrophic oceanography(Argo)program float dataset,the features of upperocean salinity stratification in the tropical Pacific Ocean are studied.The salinity component of the squared Brunt-V?is?l?frequency N2(NS2)is used to represent salinity stratification.Layer-max NS2(LMN),defined as the NS2 maximum over the upper 300 m depth,and halocline depth(HD),defined as the depth where the NS2 maximum is located,are used to specifically describe the intensity of salinity stratification.Salinity stratification in the Topical Pacific Ocean has both spatial and temporal variability.Over the western and eastern equatorial Pacific,the LMN has a large magnitude with a shallow HD,and both have completely opposite distributions outside of the equatorial region.An obvious seasonal cycle in the LMN occurs in the north side of eastern equatorial Pacific and freshwater flux forcing dominates the seasonal variations,followed by subsurface forcing.At the eastern edge of the western Pacific warm pool around the dateline,significant interannual variation of salinity stratification occurs and is closely related to the El Ni?o Southern Oscillation event.When an El Ni?o event occurs,the precipitation anomaly freshens sea surface and the thermocline shoaling induced by the westerly wind anomaly lifts salty water upward,together contribute to the positive salinity stratification anomaly over the eastern edge of the warm pool.The interannual variations in ocean stratification can slightly affect the propagation of first baroclinic gravity waves.展开更多
The variations of current, salt intrusion and vertical stratification under different conditions of river flow and wind in the Oujiang River Estuary （ORE） were investigated in this article using the Environmental Fl...The variations of current, salt intrusion and vertical stratification under different conditions of river flow and wind in the Oujiang River Estuary （ORE） were investigated in this article using the Environmental Fluid Dynamics Code （EFDC）. The model was verified against water level variation, velocity, and salinity variations in June 2005. The simulation results agreed well with measured data. Six sensitivity tests were conducted for different conditions of river flow and wind specified in the model. Model results show that salinity intrudes further upstream under scenarios with low flow and downriver local wind conditions. In contrast, the responses of salinity stratification to different environmental forcing functions were different in different portions of the estuary. Salinity stratification was enhanced under high flow condition. Model results also show that wind is not crucial to the salt intrusion and salinity stratification in the ORE.展开更多
A 3D, time-dependent, baroclinic, hydrodynamic and salinity model was implemented and applied to the Oujiang River estuarine system in the East China Sea. The model was driven by the forcing of tidal elevations along ...A 3D, time-dependent, baroclinic, hydrodynamic and salinity model was implemented and applied to the Oujiang River estuarine system in the East China Sea. The model was driven by the forcing of tidal elevations along the open boundaries and freshwater inflows from the Oujiang River. The bottom friction coefficient and vertical eddy viscosity were adjusted to complete model calibration and verification in simulations. It is demonstrated that the model is capable of reproducing observed temporal variability in the water surface elevation and longitudinal velocity, presenting skill coefficient higher than 0,82. This model was then used to investigate the influence of freshwater discharge on residual current and salinity intrusion under different freshwater inflow conditions in the Oujiang River estuary. The model results reveal that the river channel presents a two-layer structure with flood currents near the bottom and ebb currents at the top layer in the region of seawater influenced on north shore under high river flow condition. The river discharge is a major factor affecting the salinity stratification in the estuarine system, The water exchange is mainly driven by the tidal forcing at the estuary mouth, except under high river flow conditions when the freshwater extends its influence from the river＇s head to its mouth.展开更多
基金The National Key R&D Program of China under contract No.2018YFA0605702the National Natural Science Foundation of China under contract Nos 41876002 and 41776002the Fundamental Research Funds for the Central Universities under contract Nos 2017B04714 and 2017B4114
文摘Using a gridded array for real-time geostrophic oceanography(Argo)program float dataset,the features of upperocean salinity stratification in the tropical Pacific Ocean are studied.The salinity component of the squared Brunt-V?is?l?frequency N2(NS2)is used to represent salinity stratification.Layer-max NS2(LMN),defined as the NS2 maximum over the upper 300 m depth,and halocline depth(HD),defined as the depth where the NS2 maximum is located,are used to specifically describe the intensity of salinity stratification.Salinity stratification in the Topical Pacific Ocean has both spatial and temporal variability.Over the western and eastern equatorial Pacific,the LMN has a large magnitude with a shallow HD,and both have completely opposite distributions outside of the equatorial region.An obvious seasonal cycle in the LMN occurs in the north side of eastern equatorial Pacific and freshwater flux forcing dominates the seasonal variations,followed by subsurface forcing.At the eastern edge of the western Pacific warm pool around the dateline,significant interannual variation of salinity stratification occurs and is closely related to the El Ni?o Southern Oscillation event.When an El Ni?o event occurs,the precipitation anomaly freshens sea surface and the thermocline shoaling induced by the westerly wind anomaly lifts salty water upward,together contribute to the positive salinity stratification anomaly over the eastern edge of the warm pool.The interannual variations in ocean stratification can slightly affect the propagation of first baroclinic gravity waves.
基金supported by the National Basic Research Program of China (973 Program,Grant No.2006CB403302)the National Natural Science Foundation of China (Grant Nos.50839001,50779006)
文摘The variations of current, salt intrusion and vertical stratification under different conditions of river flow and wind in the Oujiang River Estuary （ORE） were investigated in this article using the Environmental Fluid Dynamics Code （EFDC）. The model was verified against water level variation, velocity, and salinity variations in June 2005. The simulation results agreed well with measured data. Six sensitivity tests were conducted for different conditions of river flow and wind specified in the model. Model results show that salinity intrudes further upstream under scenarios with low flow and downriver local wind conditions. In contrast, the responses of salinity stratification to different environmental forcing functions were different in different portions of the estuary. Salinity stratification was enhanced under high flow condition. Model results also show that wind is not crucial to the salt intrusion and salinity stratification in the ORE.
基金financially supported by the National Natural Science Foundation of China(Grant No.50339010)the National Key Technology R & D Program of China(Grant No.2012BAB03B01)State water pollution control and management of Special Science and Technology Project(Grant No.2009zx07210-10)
文摘A 3D, time-dependent, baroclinic, hydrodynamic and salinity model was implemented and applied to the Oujiang River estuarine system in the East China Sea. The model was driven by the forcing of tidal elevations along the open boundaries and freshwater inflows from the Oujiang River. The bottom friction coefficient and vertical eddy viscosity were adjusted to complete model calibration and verification in simulations. It is demonstrated that the model is capable of reproducing observed temporal variability in the water surface elevation and longitudinal velocity, presenting skill coefficient higher than 0,82. This model was then used to investigate the influence of freshwater discharge on residual current and salinity intrusion under different freshwater inflow conditions in the Oujiang River estuary. The model results reveal that the river channel presents a two-layer structure with flood currents near the bottom and ebb currents at the top layer in the region of seawater influenced on north shore under high river flow condition. The river discharge is a major factor affecting the salinity stratification in the estuarine system, The water exchange is mainly driven by the tidal forcing at the estuary mouth, except under high river flow conditions when the freshwater extends its influence from the river＇s head to its mouth.
