Extreme Marine Heatwaves – the longest, largest and most intense events — Australian Meteorological and Oceanographic Society
  1. Schedule
  2. 41(i). Ocean extremes and their impacts
  3. Extreme Marine Heatwaves – the longest, largest and most intense events

Extreme Marine Heatwaves – the longest, largest and most intense events (#83)

Alex Sen Gupta 1 , Mads Thomsen 2 , Jessica Benthuysen 3 , Alistair Hobday 4 , Eric Oliver 5 , Lisa Alexander 1 , Michael Burrows 6 , Markus Donat 7 , Ming Feng 8 , Neil Holbrook 9 , Sarah Perkins-Kirkpatrick 1 , Pippa Moore 10 , Regina Rodrigues 11 , Hilliary Scannell 12 , Andrea Taschetto 1 , Caroline Ummenhoffer 13 , Thomas Wernberg 14 , Dan Smale 15
  1. University Of New South Wales, Kensington, NSW, Australia
  2. School of Biological Sciences, University of Canterbury, Canterbury
  3. Australian Institute of Marine Science, Crawley
  4. CSIRO Oceans and Atmosphere, Hobart
  5. Department of Oceanography, Dalhousie University, Halifax
  6. Scottish Association for Marine Science, , Scottish Marine Institute, , Oban
  7. Barcelona Supercomputing Center, , Barcelona,, Spain
  8. CSIRO Oceans and Atmosphere, Perth
  9. Institute for Marine and Antarctic Studies, , University of Tasmania, Hobart
  10. Aberystwyth University, Aberystwyth
  11. Coordenadoria de Oceanografia - Universidade Federal de Santa Catarina, Florianópolis
  12. School of Oceanography, University of Washington, Seattle
  13. Department of Physical Oceanography, , Woods Hole Oceanographic Institution, , Woods Hole
  14. UWA Oceans Institute and School of Biological Sciences, Perth
  15. Marine Biological Association of the United Kingdom, Plymouth

Strong and long MHWs can have serious impacts on marine ecosystems and reliant industries. But which are the strongest and longest MHWs? Have they been examined in the literature? Do they have common characteristics, driving mechanisms and biological responses?


In this work we use a common MHW framework to catalogue the strongest, longest and largest events over the Satellite era. We find that characteristics of the most extreme events are strongly modulated by ENSO and that there is a warm season bias in the occurrence of these events, likely linked to shallower mixed layers. Most extreme subtropical MHWs are triggered by persistent high-pressure systems that are associated with increased insolation, weaker surface winds (that lead to less turbulent heat fluxes) and increased warm water Ekman transport. More broadly, almost all of the most extreme MHW are associated with weaker surface winds. Finally, we also find a significant response in primary productivity to these events, with reduced production at low to mid latitudes and some enhanced productivity at high latitudes.

 

#amos2020