Baroclinic Effect on Modeling Deep Flow in Brown Passage, BC, Canada

Abstract

Brown Passage is a deep (up to 200 m) ocean channel connecting the western offshore waters of Hecate Strait and Dixon Entrance on the Pacific continental shelf with the eastern inland waters of Chatham Sound in Northern British Columbia, Canada. A high-resolution 3D finite difference hydrodynamic model, COastal CIRculation and SEDiment transport Model (COCIRM-SED), was developed in 2010 and 2013 to determine the tidal and wind-driven currents of this area. The barotropic model results for ocean currents were found to be in reasonably good agreement with the historical ocean current observations at near-surface and middle depth available for Brown Passage. Operated from October 2014 to April 2015, the first modern oceanographic measurement program in Brown Passage found surprisingly strong near-bottom currents (the 99th percentile current speed reaches 53 cm/s at 196 m). As a result, the COCIRM-SED model was modified and rerun, with the most important change incorporating water density/salinity fields as modeled variables. This change led to considerable improvements in the ability of the model to generate episodes of relatively strong currents in the bottom layers. The bottom intensification in ocean currents in Brown Passage is shown to be due to semi-diurnal internal tides, which were not previously included in the barotropic version of the 3D model. This finding for the near-bottom flow from the qualitative modeling study is important for applications of the potential sediment deposition and resuspension studies.

Modeling the Transport and Fate of Sediments Released from Marine Construction Projects in the Coastal Waters of British Columbia, Canada

“…This example of numerical modeling of sediment transport is from Brown Passage, which connects the inland sea of Chatham Sound to the deeper Pacific Waters of Hecate Strait and Dixon Entrance [29]. The construction activity simulated is for ocean dumping from barges for disposal of dredged sediments at a proposed site in approximately 200 m water depth ( Figure 10).…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements [29]. The STFATE IDZ model was used to represent the short term distribution of the sediment releases as input to the 3D hydrodynamic model.…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements[29].…”

Modeling the Transport and Fate of Sediments Released from Marine Construction Projects in the Coastal Waters of British Columbia, Canada

“…This example of numerical modeling of sediment transport is from Brown Passage, which connects the inland sea of Chatham Sound to the deeper Pacific Waters of Hecate Strait and Dixon Entrance [29]. The construction activity simulated is for ocean dumping from barges for disposal of dredged sediments at a proposed site in approximately 200 m water depth ( Figure 10).…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements [29]. The STFATE IDZ model was used to represent the short term distribution of the sediment releases as input to the 3D hydrodynamic model.…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements[29].…”

Modeling the Transport and Fate of Sediments Released from Marine Construction Projects in the Coastal Waters of British Columbia, Canada

“…This example of numerical modeling of sediment transport is from Brown Passage, which connects the inland sea of Chatham Sound to the deeper Pacific Waters of Hecate Strait and Dixon Entrance [27]. The construction activity simulated is for ocean dumping from barges for disposal of dredged sediments at a proposed site in approximately 200 m water depth ( Figure 10).…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements [27]. The STFATE IDZ model was used to represent the short term distribution of the sediment releases as input to the 3D hydrodynamic model.…”

Modeling the Transport and Fate of Sediments Released from Marine Construction Projects in the Coastal Waters of British Columbia, Canada

“…This example of numerical modeling of sediment transport is from Brown Passage, which connects the inland sea of Chatham Sound to the deeper Pacific Waters of Hecate Strait and Dixon Entrance [29]. The construction activity simulated is for ocean dumping from barges for disposal of dredged sediments at a proposed site in approximately 200 m water depth ( Figure 10).…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements [29]. The STFATE IDZ model was used to represent the short term distribution of the sediment releases as input to the 3D hydrodynamic model.…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements[29].…”

Modeling the Transport and Fate of Sediments Released from Marine Construction Projects in the Coastal Waters of British Columbia, Canada

“…This example of numerical modeling of sediment transport is from Brown Passage, which connects the inland sea of Chatham Sound to the deeper Pacific Waters of Hecate Strait and Dixon Entrance [27]. The construction activity simulated is for ocean dumping from barges for disposal of dredged sediments at a proposed site in approximately 200 m water depth ( Figure 10).…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements [27]. The STFATE IDZ model was used to represent the short term distribution of the sediment releases as input to the 3D hydrodynamic model.…”

Modeling the Transport and Fate of Sediments Released from Marine Construction Projects in the Coastal Waters of British Columbia, Canada

“…This example of numerical modeling of sediment transport is from Brown Passage, which connects the inland sea of Chatham Sound to the deeper Pacific Waters of Hecate Strait and Dixon Entrance [29]. The construction activity simulated is for ocean dumping from barges for disposal of dredged sediments at a proposed site in approximately 200 m water depth ( Figure 10).…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements [29]. The STFATE IDZ model was used to represent the short term distribution of the sediment releases as input to the 3D hydrodynamic model.…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements[29].…”

Modeling the Transport and Fate of Sediments Released from Marine Construction Projects in the Coastal Waters of British Columbia, Canada

“…This example of numerical modeling of sediment transport is from Brown Passage, which connects the inland sea of Chatham Sound to the deeper Pacific Waters of Hecate Strait and Dixon Entrance [27]. The construction activity simulated is for ocean dumping from barges for disposal of dredged sediments at a proposed site in approximately 200 m water depth ( Figure 10).…”

“…Wind forcing is applied through the model surface boundary conditions using wind data measurements at the nearby Lucy Island weather station. The initial temperature and salinity distribution within the model domain are derived from DFO historical CTD measurements [27]. The STFATE IDZ model was used to represent the short term distribution of the sediment releases as input to the 3D hydrodynamic model.…”