Marine Heat Wave

About Marine Heat Wave:

• A marine heat wave is an extreme weather event.
• It occurs when the surface temperature of a particular region of the sea rises to 3 or 4 degree Celsius above the average temperature for at least five days. 
• MHWs can last for weeks, months or even years, according to the US government’s agency National Oceanic and Atmospheric Administration (NOAA).
• Impacts
  • MHWs are prolonged temperature events that can cause severe damage to marine habitats, such as impacts to coral reefs and species displacement.
  • These events are becoming more frequent due to global warming, with notable occurrences off Australia's East Coast and Tasmania, as well as the northeast Pacific coast and North Atlantic.
  • Higher ocean temperatures, which are associated with MHWs, can make storms like hurricanes and tropical cyclones stronger.
  • MHWs also fuel the growth of invasive alien species, which can be destructive to marine food webs. 
  • When storms travel across hot oceans, they gather more water vapour and heat.
  • This results in more powerful winds, heavier rainfall and more flooding when storms reach the land — meaning heightened devastation for humans.

Q1: What is a tropical cyclone?

It is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain.

Source:  Why researchers studied marine heat waves more than 200m below the ocean surface