Assessment of Port Ocean Prediction System developed under Canada's Oceans Protection Plan : Vancouver Harbour

Canada's Oceans Protection Plan (OPP) was launched in 2016 to support initiatives aimed at protecting our marine environment from anthropogenic pressures. To this end, the Improving Drift Prediction and Nearshore Modelling sub-initiative of OPP developed six high-resolution port-scale hydrodynamic models, to improve safe navigation, and provide operational emergency response to events such as marine oil spills. The models were downscaled from the Coastal Ice-Ocean Prediction Systems East and West (CIOPS-E, CIOPS-W). Atmospheric forcing was provided by the High-Resolution Deterministic Prediction System (HRDPS). Model performance is assessed against available observational data and contrasted with the parent model using a multi-year hindcast. Evaluations of 48-hour forecasts are performed during a two-month period. This document reports on the performance assessment for the Vancouver Harbour model (VH20) and the northern part of the South Salish Sea model (SSS150). The VH20 domain covers English Bay to Port Moody Arm and is nested within SSS150 that covers Burrard Inlet and the southern part of Salish Sea and the Fraser River to Mission and to Pitt Lake. Results show that the high-resolution models provide either similar or better performance than the larger-scale models in the areas where they overlap and have adequate performance in the areas not covered by the larger-scale models. At most water level stations, tidal water level error is 5-6 cm CRMSE and non-tidal water level error is 4-5 cm, giving a total water level error of about 7 cm CRMSE, with one exception at 9 cm CRMSE. At Second Narrows, mean outflow of order 14 cm/s is captured by both models and total CRMSE for the alongshore current ranges from 16.3-27.0 cm/s. Surface water temperature near English Bay is biased cold by about 0.7 °C and modelled to 1 °C CRMSE. Temperature and salinity profiles in Howe Sound and English Bay outperform the Salish Sea model at 500 m nominal resolution (SS500; part of CIOPS-W) and this level of performance is maintained in the rest of Burrard Inlet. Drift evaluation indicates that VH20 marginally outperforms SSS150 although large uncertainties limit the ability to constrain the performance. The forecast evaluation showed that non-tidal water level error increased gradually with forecast lead time as expected. All model runs completed without stability issues including periods of extreme weather events and real-time instrument failure.