Marine heatwaves are increasing, both in the amount of time they last and in their intensity. Because of their potential impacts on fisheries and other marine goods and services, scientists are working to understand and develop practical marine heatwave predictions.
New research, funded in part by CPO’s Climate Variability & Predictability (CVP) and Modeling, Analysis, Predictions, and Projections (MAPP) programs, helps identify the main drivers of marine heatwaves. Published in Frontiers in Marine Science, the study, led by Robert Schlegel, Eric Oliver, and Ke Chen of Woods Hole Oceanographic Institution and Dalhousie University, determined which of the many possible physical processes have the most impact on the onset and/or decline of marine heatwaves on the Northwest Atlantic continental shelf.
The authors found that latent heat flux is the most common driver of the start of marine heatwaves, with almost half the past heat waves on the shelf initiated by positive heat flux anomalies into the ocean. On the other hand oceanic processes focused on transport and movement, such as advection and mixing, drive the decay of most heat waves. These findings have implications for how larger-scale circulation systems like the Gulf Stream or Labrador Current might have played different roles in producing and diminishing heatwave variability on the shelf.