• Introduction
• Forecasts
  • Hawaiian Islands
  • Pacific Islands
• Output Diagnostics
  • Overview
  • Observations
  • Analysis Compared to Observations
  • Analysis Compared to Forecast
  • Forecast Comparison
• Forecast Transects
• Forecast Trajectories
• Waikiki Current Predictions
• PacIOOS Ala Wai Turbidity Plume Model

Regional Ocean Modeling System (ROMS)

The PacIOOS ocean modeling component uses the open source, community-supported Regional Ocean Modeling System (ROMS). ROMS is a free-surface, hydrostatic, primitive equation model discretized with a terrain-following vertical coordinate system. It is coded in parallel for multi-threaded and multi-process architectures and has been widely applied in many applications from planetary scales down to the scales of estuarine environments. Forecasts include predictions of water temperature, ocean currents, salinity, and sea surface height.

Hawaiian Islands Models

Boundaries of the three different ROMS model regions outlined in yellow; inset image provides a close-up over Oahu.

Google Earth KMZ file of the above ROMS model boundaries.

Hawaiian Islands ROMS Model (Regional Scale)

This model covers the entirety of the Hawaiian Islands (neglecting the Northwestern Hawaiian Islands preserve) at a horizontal resolution of 4 kilometers, with 30 terrain-following vertical levels. Boundary conditions are provided by the 1/12° HYbrid Coordinate Ocean Model (HYCOM). Every day, all available observations collected for the past three days are assimilated (PacIOOS ocean gliders, Argo floats, high-frequency radio (HFR), satellite data, etc.) to provide a "nowcast" for the current ocean conditions. From this nowcast, an ensemble of 7-day forecasts is generated to provide the best ocean circulation estimate with uncertainty for the next week.

Oahu ROMS Model (Island Scale)

This model covers the ocean south and west of the island of Oahu at varying resolution from 2 kilometers to 700 meters in the horizontal. It is nested within the larger Hawaiian Islands Regional Model, and the same data are assimilated again to resolve finer-scale features (e.g., Penguin Bank). Daily nowcasts and 7-day forecasts are generated.

Oahu South Shore ROMS Model (Local Scale)

This model covers Māmala Bay with a focus on the beaches at Waikīkī. It is of fine-scale down to 60 meters resolution at the coast. Because of the short-scale dynamics, forecasts are only produced for up to 3 days. This model allows us to examine the outflow during rain events and the conditions along Hawaii's most populous beaches.

Waikiki ROMS Model (Local Scale)

This model covers the Waikiki beach area and provides 3-day hourly forecasts with a resolution of approximately 40 meters. This model also allows for daily turbidity observations of the Ala Wai Canal.

Data Access And Visualization

• Data Archive (THREDDS Data Server)
• Daily Snapshot
• PacIOOS Voyager
• Live Access Server (LAS)

Western North Pacific ROMS Models

Western North Pacific ROMS Model (Regional Scale)

This model covers the Western North Pacific Ocean region and provides a daily 3-hourly, 7-day forecast with approximately a resolution of 4 kilometers.

Mariana Islands ROMS Model (Island Scale)

This model covers a portion of the Mariana Islands, including Guam. The model provides a daily 3-hourly, 6-day forecast with approximately a resolution of 2 kilometers.

American Samoa ROMS Model

American Samoa ROMS Model (Island Scale)

This model covers American Samoa and surrounding islands and provides a daily 3-hourly, 7-day forecast with approximately a resolution of 3 kilometers.