New Zealand marine heatwave forecast
Marine heatwaves can have devastating effects on marine ecosystems and industries. The Moana Project is using advanced ocean models to predict when and where marine heatwaves will affect New Zealand coastal and oceanic waters.
Below is the Moana Project forecast for marine heatwaves in New Zealand. The figures show an animation of the forecasted sea surface temperatures for the next seven days.
Sea surface temperatures forecasted for the upcoming 7 days.
Difference between forecasted sea surface temperatures and the long-term average for this time of year. Red shading indicates that the ocean is currently warmer than normal; blue that it is colder.A marine heatwave is an extended period of extremely warm ocean temperatures (the scientific definition of a marine heatwave is when seawater temperatures are warmer than the 90th percentile of the local long-term (25-year) average for at least five consecutive days)1. As climate change affects our oceans, marine heatwaves are expected to become more frequent, intense and longer lasting. Our ocean life around New Zealand has evolved to thrive in cooler seas and marine heatwaves can have devastating effects on local ecosystems. They also pose a threat to aquaculture and fisheries, New Zealand industries worth more than $4 billion annually.
As part of the Moana Project, we are investigating marine heatwaves around New Zealand to learn more about how they are changing, their causes, and how to better predict them. Moana Project team members Dr. Robert Smith (University of Otago), Dr. Carine Costa, Phellipe Couto and Dr. Joao Souza (MetOcean Solutions) have set up New Zealand’s first nation-wide, open-access ocean modelling system which we are using to forecast when and where marine heatwaves will occur.
Forecasting sea surface temperatures
The graphs below show sea surface temperatures at selected coastal sites (the black boxes from the maps above) around New Zealand. The graphs show the conditions of the last three weeks (thin line), and the forecast for the next seven days (thick line). Red shading appears when temperatures are above the marine heatwave threshold. When they have been above the threshold for five days in a row, the area is experiencing a marine heatwave.
The forecasts above show the average sea surface temperatures for larger coastal areas. Within these larger areas, temperatures may differ from site to site due to local topography. For example, shallow waters within enclosed bays may be warmer. The model used has a 5 km by 5 km grid, which means that small-scale local variations may not show.
In the Moana Project…
We are studying marine heatwaves around New Zealand. Focusing on locations used by the fishing and aquaculture industries, we are investigating trends and variability in marine heatwaves and the local and large-scale environmental factors causing them. We are also using machine learning to help us get better at predicting when marine heatwaves will strike New Zealand waters in the future.
