Last edited June 10, 2016

LiveOcean: a daily forecast model of ocean acidification properties for Washington coastal waters

LiveOcean is a computer model simulating ocean water properties in the NE Pacific and Salish Sea. The project goal is to provide 3-7 day forecasts of Aragonite saturation state and pH of waters entering shellfish growing areas on the coast. The project is funded by Washington state through the Washington Ocean Acidification Center (WOAC). The model system is built using existing 3D circulation-biogeochemistry hindcast models, incorporating carbon chemistry.

The circulation model is currently creating 3-day forecasts of currents, temperature & salinity that may be viewed and compared to observations in the NANOOS NVS (click on the Models button, and then LiveOcean Salinity or Water Temperature).

Disclaimer: The coastal ocean forecasts made by LiveOcean are an experimental product intended for research use only. In no event will UW or any of its employees be liable for any direct, indirect, incidental, consequential, special or exemplary damages or lost profit resulting from any use or misuse of these research model forecasts.

LiveOcean is an ongoing project of the UW Coastal Modeling Group: Dr. Parker MacCready (UW Oceanography, lead), Dr. Samantha Siedlecki (UW JISAO, oxygen & carbon chemistry), Dr. Ryan McCabe (UW JISAO, validation), and Dr. Neil Banas (University of Strathclyde, Scotland, ecosystem modeling).

Figure 1. Tidally-averaged Surface salinity (left), temperature and currents (right) from the LiveOcean hindcast of 2014. The full model domain is shown, which includes the Washington coast, and parts of the Oregon and Vancouver Island coasts. The Salish Sea is included, although it is not well-resolved with the current 1.5 km horizontal grid.

Model Configuration

Forcing

Validation

Testing model performance against observations is essential to knowing how to use the forecasts. We put about half of our effort into validation, gathering observations from many regional scientific and monitoring efforts. An example it shown in in Fig. 2. We are using a 2013 hindcast as our main validation year because a great deal of carbon chemistry data exists for that year. The model system is built using a framework developed to forecast Harmful Algal Blooms (PNWTOX, Dr. Barbara Hickey, PI). Extensive model physical validation is documented in Giddings et al. (2014). The ecosystem model and its validation are given in Davis et al. (2014). Siedlecki et al. (2015) present the detritus and oxygen model and its validation.

Figure 2. Comparison of model temperature and salinity to mooring records collected by the Olympic Coast National Marine Sanctuary (OCNMS). The mooring is in 27 m of water off the central Washington shelf (map, upper right). The model was run for a full year hindcast of 2013 and observations (black lines in left panels) were collected during the summer and early fall months. At this location the model (gray lines) shows good skill at reproducing both the mean and the variability of the temperature and salinity. The fields shown are "subtidal" meaning they have been filtered to remove tidal oscillations.

These comparisons look excellent, however they are just for a single location and only for temperature and salinity, which have well-understood physics. In general model skill decreases as you move farther offshore, and as it tries to simulate biogeochemical properties such as hypoxia and ocean acidification.

Next Steps

REFERENCES