page_title: Cyclonic Niño
section_title: Effects
hierarchical_section_title: Cyclonic Niño / Effects
context_page_description: Cyclonic Niño is a climatological phenomenon that has been observed in climate models where tropical cyclone activity is increased. Increased tropical cyclone activity mixes ocean waters, introducing cooling in the upper layer of the ocean that quickly dissipates and warming in deeper layers that lasts considerably more, resulting in a net warming of the ocean.
  In climate simulations of the Pliocene, this net warming is then transported by ocean currents and part of it ends up in the Eastern Pacific, warming it relative to the Western Pacific and thus creating El Niño-like conditions. Reconstructed temperatures in the Pliocene have shown an El Niño-like pattern of ocean temperatures that may be explained by increased tropical cyclone activity and thus increased temperatures in the Eastern Pacific. Some of the heat is transported away from the tropics and may be responsible for past episodes of warmer-than-usual climate, such as in the Eocene and Cretaceous, although there is no agreement on the predominant effects of tropical cyclones on heat transport away from the tropics.
context_section_description: The "Cyclonic Niño" effect could partially explain temperature distributions in the Pliocene and a flattening of the oceanic thermocline during the Pliocene. The permanent El Niño conditions may have had effects similar to that of present-day El Niño, although this is not undisputed. A permanent El Niño would suppress hurricane activity in the North Atlantic less effectively than a present-day El Niño, owing to different thermodynamic effects of transitory warming.
  Stronger tropical cyclones are expected to cause more mixing of the ocean and thus a stronger effect on heat transport. Anthropogenic global warming is expected to increase the frequency of intense tropical cyclones and thus may induce a Cyclonic Niño effect. Increased hurricane activity in the Central Pacific could be a consequence.
caption: El Niño induced changes in atmospheric circulation