Marine heatwaves – Importance of sustained observations

Ming Feng, Jessica Benthuysen, Madeleine Cahill, Eric Oliver, Anthony Richardson, Moninya Roughan, Amandine Schaeffer, Paul Thomson

With contributions from Neil Holbrook, Susan Wijffels and more 2011 Ningaloo Nino

Satellite

Surface Meteorology

Shelf moorings

Feng et al. 2013 Argo float Wernberg et al. 2013

Bridge et al. 2014 increased abundance with

Marine heat marine heat wave wave elevated abundance of Prochlorococcus throughout 2011 = change in phytoplankton Record strength LC community composition?

Thomson

Zooplankton biomass

Implications for higher trophic levels… Savage, Richardson et al. (in prep) Detection and attribution using National Reference Station time series

2011 marine heatwave

Freshening of the Leeuwin Stronger Leeuwin Current observed from moorings

(a) Climatology Mean

Jan ADCP mooring data have been used to quantify the mean Apr structure of onshore influences of the Leeuwin Current:

Oct

Jul The Leeuwin is strong during austral autumn-winter and weak during austral summer;

The Leeuwin is strong during La Nina event 2010-2011 (marine heatwave event), and is weaker during the 2014- 2015; (b) 2011 & 2015 Eddy’s role in the Leeuwin Current momentum balance is being analysed using the mooring data, in combination with Bluelink model results.

Liu et al. in preparation

Detecting marine heat waves off the NW Shelf

Thermosalinograph temperature OISSTv2 (AVHRR) temperature near-surface (2 m), hourly-averaged (0.25° x 0.25°), from nearest grid cell

6 Jan – 30 Mar 2016

Darwin

Broome

Advanced Very High Resolution Radiometer RV Solander in a marine heat wave (SST > threshold, for > 5 days) (Hobday, et al. 2016); based on 1982-2015 climatology not in a marine heat wave

(°C) Traversing waters in marine heat wave along the GBR Thermosalinograph temperature OISSTv2 (AVHRR) temperature near-surface (2 m), hourly-averaged (0.25° x 0.25°), from nearest grid cell

25 Feb – 29 Feb 2016

1 – 20 Feb 3 Mar – Townsville 21 Mar

RV Cape Ferguson Advanced Very High Resolution Radiometer : in a marine heat wave (SST > threshold, for > 5 days) (Hobday, et al. 2016); based on 1982-2015 climatology : not in a marine heat wave (°C) Slocum gliders track sub-surface warming in the March 2016 Cooktown Surface Temperature Anomaly North 22 Mar 2016 East

°S

Cairns 12 Apr 2016

0 m 50 m 100 m °E 200 m IMOS OceanCurrent News, 24 May 2016 (°C) 2015-2016 SE Australia MHW

 There was a marine heatwave Mean 2015-2016 DJF SST that occurred last summer off Anomaly southeastern Australia:  9 Sep 2015 – 16 May 2016  It is unprecedented in − Duration (251 days) − Intensity (2.9OC max)  Impacts: POMS (Oysters), dead abalone, poor salmon farm performace, strange fish intrusions, kelp thinning…  Oliver, Benthuysen, Bindoff, Hobday, Holbrook, Mundy and Perkins-Kirkpatrick, Nat Comms (under review)

NOAA OI SST Nearshore Record

 Nearshore Records  IMOS Maria Island NRS − 20 m temperature − Full-depth velocities  IMAS Nearshore Temperature Monitoring − A number of sites in − 6-20 m depth  This event was record strength (approx. 10-year records) in the coastal zone  Record southward flows, possible indication of forcing mechanism Data streams to describe marine heatwaves

NRS and Shelf moorings – continuous, capturing sub-monthly variability

Gliders – infrequent, vertical structure, real time

SOOP tropical vessels – surface, mixed spatial and temporal, opportunistic but real time

Remote sensing and Oceancurrent – large-scale patterns, near-surface properties

Bluewater observations including Argo – large-scale structures, feed into prediction models, such as OceanMAPS

NRS samplings, AUV – biogeochemical impacts non-IMOS contributions – temperature loggers, shelf models funded by projects, State Government agencies, industries? Drivers of marine heatwaves

West coast, Ningaloo Nino – Leeuwin Current transport, air-sea heat flux  La Nina, local air-sea coupling

Northwest coast, offshore atolls – air-sea heat flux  El Nino, Indian Ocean Dipole, Australian Monsoon, MJO

Northern and northeast coast, GBR – air-sea heat flux, boundary currents  El Nino, Australian Monsoon

Southeast coast – EAC transport  strengthening EAC and eddies, local alongshore wind, climate mode?