2025-03-09 Spring Diatom Bloom Forecast

The current best estimate of the first spring diatom bloom in the Strait of Georgia is 2025-03-12. That estimate is based on a run of the SOG biophysical model for deep estuaries [1] with the following parameters:

  1. Run start date/time: 2024-09-19
  2. Actual wind, meteorological, and river flow forcing data to 2025-03-08, and historical data from 2009 thereafter

2009 has the median bloom date in an ensemble of SOG runs that use historical wind, meteorological, and river flow data from 1980 through 2010 as future forcing data after 2025-03-08.

Best estimate bounds on the bloom date are:

  • No earlier than 2025-03-10 based on using actual forcing data to 2025-03-08, and data from 2004/2005 thereafter. 2005 has the 5th centile bloom date in the ensemble of SOG runs.
  • No later than 2025-03-22 based on using actual forcing data to 2025-03-08, and data from 2001/2002 thereafter. 2002 has the 95th centile bloom date in the ensemble of SOG runs.

[1] Allen, S. E. and M. A. Wolfe. (2013). Hindcast of the Timing of the Spring Phytoplankton Bloom in the Strait of Georgia, 1968-2010. Progress in Oceanography, volume 115, pp 6-13. https://dx.doi.org/10.1016/j.pocean.2013.05.026

Data Sources

The forcing data used to drive the SOG model is obtained from several sources:

Disclaimer

This site presents output from a research project. Results are not expected to be a robust prediction of the timing of the spring bloom. At this point, we believe such a prediction is not possible before mid-February using any model and this model is not yet tested.

Time Series

Profiles from Median Prediction Profiles from Median Prediction Profiles from Median Prediction

Profiles at 2025-03-08 12:00 from Median Prediction

Profiles from Median Prediction

Bloom Date Evolution

Actual to Ensemble Forcing Transition Date Median 5th Centile Early Bound 95th Centile Late Bound Earliest Ensemble Result Latest Ensemble Result
Bloom Date Ensemble Member Bloom Date Ensemble Member Bloom Date Ensemble Member Bloom Date Ensemble Member Bloom Date Ensemble Member
2025-03-08 2025-03-12 2009 2025-03-10 2005 2025-03-22 2002 2025-03-10 2005 2025-03-26 2003
2025-03-07 2025-03-11 1998 2025-03-08 2009 2025-03-21 2010 2025-03-08 2009 2025-03-26 2003
2025-03-06 2025-03-12 2009 2025-03-07 2005 2025-03-25 1995 2025-03-07 2005 2025-03-26 2003
2025-03-05 2025-03-12 2009 2025-03-07 2008 2025-03-25 1995 2025-03-07 2008 2025-03-26 2003
2025-03-04 2025-03-14 2007 2025-03-06 2008 2025-03-27 2003 2025-03-06 2008 2025-04-06 2009
2025-03-03 2025-03-08 1996 2025-03-05 2010 2025-03-26 2003 2025-03-05 2010 2025-04-06 2009
2025-03-02 2025-03-12 1993 2025-03-05 2010 2025-03-26 2003 2025-03-05 2010 2025-04-06 2009
2025-03-01 2025-03-13 2004 2025-03-04 1998 2025-04-05 1999 2025-03-04 1998 2025-04-06 2009
2025-02-28 2025-03-14 2004 2025-03-05 1998 2025-04-05 1999 2025-03-05 1998 2025-04-06 2009
2025-02-27 2025-03-16 1998 2025-03-07 1996 2025-04-05 1999 2025-03-06 1984 2025-04-06 2009
2025-02-26 2025-03-16 1998 2025-03-08 1984 2025-04-05 1999 2025-03-07 1996 2025-04-06 2009
2025-02-25 2025-03-16 1998 2025-03-08 1996 2025-04-05 1999 2025-03-08 1996 2025-04-06 2009
2025-02-23 2025-03-13 1991 2025-03-02 2003 2025-04-05 1999 2025-03-02 2003 2025-04-06 2009
2025-02-22 2025-03-14 2004 2025-03-04 1998 2025-04-05 1999 2025-03-02 2003 2025-04-06 2009
2025-02-21 2025-03-13 1987 2025-03-02 1990 2025-04-05 1999 2025-02-28 2003 2025-04-06 2009
2025-02-20 2025-03-13 1987 2025-02-28 2003 2025-04-05 1999 2025-02-27 2005 2025-04-06 2009
2025-02-19 2025-03-12 1993 2025-03-01 1990 2025-04-06 2009 2025-02-25 2005 2025-04-07 1999
2025-02-18 2025-03-08 1986 2025-02-25 2001 2025-04-05 1999 2025-02-23 2005 2025-04-06 2009
2025-02-17 2025-03-08 1986 2025-02-22 2005 2025-03-27 2006 2025-02-21 2010 2025-04-05 1999
2025-02-16 2025-03-12 2009 2025-02-22 2005 2025-03-27 2006 2025-02-21 2010 2025-04-05 1999
2025-02-15 2025-03-11 1986 2025-02-21 2010 2025-03-27 2006 2025-02-21 2010 2025-04-05 1999
2025-02-14 2025-03-08 1986 2025-02-21 2010 2025-03-27 2006 2025-02-20 2005 2025-04-05 1999