Forecast Origin Dates
J-SCOPE forecast results for the simulation beginning in January of 2019 are shown through a series of figures below. In the first figure, each panel represents ensemble averaged anomalies of two month averages for the region. In the second figure, the panels depict the relative uncertainty from the ensemble for the same time periods.
From the maps, oxygen is forecasted to be lower than the climatology during the upwelling season of 2019 in Washington and near climatological in Oregon. The relative uncertainty remains low (10%) until the end of the upwelling season (July - August) when the relative uncertainty gets higher (up to ~50%).
Forecasted bottom oxygen (mg/l), averaged over three ensemble members for each month, indicates declines in oxygen concentrations over the course of the forecast for both Washington and Oregon, with hypoxia (O2 < 2 mg/l) prominent over much of the Oregon shelf in June and expanding to much of the Washington shelf in July and continuing through September.
Hypoxia extends upward into the water column as well. The percentage of the water column that is forecasted to experience hypoxia (O2 < 2 mg/l) is a metric for this phenomenon. Early in the upwelling season, hypoxia is forecasted to occupy a small percentage of the water column over the entire modeled region (<10%). In July, some regions in Oregon, nearshore, and around Cape Elizabeth begin to experience more (~20%). Over the course of the summer, the percentage of the water column that is hypoxic increases coast-wide, with particularly high volumes forecasted for Heceta Bank on the Oregon shelf and around Cape Elizabeth in August and September with values of up to 50% of the water column experiencing hypoxia.
Time series of bottom oxygen from the Washington coast near one of the Olympic Coast National Marine Sanctuary (OCNMS) moorings at Cape Elizabeth (site CE042), from NH-10 mooring off of Newport, Oregon, and from the Ćháʔba· mooring off of La Push, Washington, are shown for each member of the ensemble. The model forecasts that hypoxia will most likely develop at all three moorings - but more likely at the NH-10 and CE042 moorings in early-mid June, which is about one month before the climatological onset of hypoxia (green). Another time series from the outer Washington shelf, Ćháʔba·, forecasts hypoxia onset in June is uncertain for this location as not all of the ensemble members agree.
Finally, climatological cross-sections from the Newport Line in Oregon (44°N) and the Grays Harbor Line in Washington (47°N) are compared to the forecasted average of the ensemble members during the summer upwelling season (May - August). In both Oregon and Washington, the forecast projects that the oxygen concentration for the upwelling season of 2019 will be lower than the climatology on both the shelf and at deeper depths, with the largest anomalies occurring between the surface and ~350 m depth in Oregon, and 500 m depth in Washington.
The emergence of anoxia in the model in late summer is caused by a bias associated with the lack of relaxations in the winds (found to be important in a paper by Adams et al, 2013) in the Climate Forecast System input files as well as a bias in the shortwave radiation (see 2013, Year in Review). The model does have skill in predicting the emergence and severity of hypoxia, while it is biased low for these reasons. Given the difficulty in predicting the fall transition in prior forecasts (see 2013, Year in Review), the forecast for low oxygen levels forecasted well into August is highly uncertain.