British Columbia Marine Heatwave Monitor
To understand when ocean weather is different from normal, a long-term record is needed to know what normal actually looks like. With enough observations we can then determine what conditions are abnormal or anomalous. With extensive ocean monitoring off Canada’s west coast for many decades, CIOOS Pacific is currently developing a tool to monitor for current and historic marine heatwaves. The map above shows weather buoys (many that have been in operation for 30+ years) operated and maintained by Environment and Climate Change Canada and Fisheries and Oceans Canada. These buoys are an initial target for this application and more datasets and types will be added.
How Is A Marine Heatwave Defined?
Just as on land, marine temperatures can go through extreme periods. Extreme differences from normal (or climatology) may occur any time of year, but when they are sufficiently different for a sustained period (five days or more) then heatwave conditions have been met. The more extreme the anomalous conditions, the more severe the heatwave category. A complete description of marine heatwaves may be found within Hobday et al. 2016 and Hobday et al. 2018.
Among the best known marine heatwaves in recent memory was « The Blob » that persisted in the northeast Pacific from the end of 2013 through 2016. At its peak, significantly anomalous temperatures (2.5 °C or 4.5 °F) covered a surface area about the size of Australia and extended beneath the surface hundreds of metres.
The CIOOS Pacific Marine Heatwave Monitor will compliment MarineHeatwaves.org, a great resource based on satellite observations.
Marine heatwaves may affect all marine life from microscopic phytoplankton to the largest whales, depending on their extent and duration. Altered circulation during these events changes food supplies in the marine environment. Mobile organisms have a harder time finding food and immobile organisms may be unable to adapt or succumb to other disease as a result of their weakened state. Scientists are still investigating all the ramifications of « The Blob » and each new event adds to our understanding.