Are heatwaves Present in the ocean?
High temperatures and heatwaves across the globe saw records broken in July 2023 on land and in the oceans. The oceans serve as the Earth's heat reservoir, absorbing substantial amounts of thermal energy as a result of their continuous interaction with the atmosphere. Under specific conditions prolonged periods of unusually high temperatures in the oceans are called marine heatwaves much like their atmospheric counterparts.These higher temperatures could be driven by increased heat input from the atmosphere. decreased heat losses from the ocean or the transfer of warmer water masses through currents Over the past two decades these events have become more prevalent and widespread, having been observed in various areas of the global ocean, in both regional and large scales, at the surface of the ocean and at depth
In particular, recent data shows the occurrence of marine heatwaves surged by 34 percent between 1925 and 2016. While the exact mechanisms triggering marine heatwaves vary from region to region. There are two primary factors. In some instances, the atmospheric conditions themselves play a pivotal role. During such episodes, stagnant air masses and prolonged high temperatures in the atmosphere conspire to heat the ocean's surface setting the stage for a marine heatwave event. This pattern was notably evident during a 2012 North Atlantic event, which saw one of the highest sea surface temperatures ever recorded.
In other cases, the main driver is the movement of ocean currents, which transport relatively warm water masses to new areas. When these warm masses converge in specific regions, they cause a rapid and abrupt increase in the sea's surface temperature. This was witnessed in the 2015 Tasman Sea (situated between Australia and New Zealand) event.
As the impacts of marine heatwaves reverberate across the globe, understanding the complex interplay between the oceans and the atmosphere is crucial for predicting the Occurrence of these extreme events. In the face of climate change, conserving and protecting our oceans becomes ever more critical. Therefore improving marine heatwave predictability is crucial to empower communities and ecosystems alike to adapt and build resilience. By better understanding the science behind marine heatwaves and taking collective action, people can work towards a more resilient and sustainable future for the oceans. (With inputs from agencies).
Picture Credit : Google