Oral Presentation AMOS Annual Meeting and International Conference on Tropical Meteorology and Oceanography

Monitor the evolution and demise of an extreme marine heatwave event with sustained coastal observing system off Rottnest, Western Australia   (#34)

Miaoju Chen 1 , Ming Feng 1 , Qinyan Liu 1 2 , Nick Mortimer 1
  1. CSIRO Oceans and Atmosphere, Crawley, WA, Australia
  2. South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China

Extreme events such as the marine heatwaves have become more frequent in a warming ocean. These extreme events can extend to water column, and have been playing a growing role in shaping the functions of the marine ecosystems. It is crucial to predict the occurrences of these extreme events to mitigate their impacts. In this study, we present data streams from a sustained marine observation system off Rottnest, Western Australia in the Integrated Marine Observing System (IMOS), including a biogeochemical mooring and an array of shelf moorings, together with ocean glider dataset. These sustainable dataset allows us to to identify and characterize these extreme events, and to examine their effect on chlorophyll concentrations over depth. Moored temperature data have captured the evolution and demise of the 2011 event (summer) in the water column- the highest magnitude warming event on record, and both moored ocean salinity and current measurements can be used to attribute the event to a large extent to the unseasonable surge of a warm eastern boundary current, the Leeuwin Current. The warming signals and their vertical extent have also been captured repeat glider transects. Moored chlorophyll sensors have been evaluated against bottle sampling measurement and CTD casts to assess the marine heatwave impacts on the pelagic marine environment. The sustained observations at multiple shelf locations are thus valuable for monitoring and attributing environmental risks associated with the marine heatwaves.