The IMOS Event Based Sampling Sub-Facility uses Ocean Gliders to monitor marine heatwaves in Australian coastal waters, with up to four deployments per year. The ability of Ocean Gliders to provide high-resolution temporal and spatial observations of sub-surface ocean temperature and their relative portability make them a valuable tool for monitoring marine heatwaves. The ability to measure temperature but also key bio-physical variables (including oxygen, chlorophyll, salinity) aids in understanding the growth, peak and decay of these extreme ocean temperature events and their potential impacts on the marine environment.
Data is transmitted from Ocean Gliders in near real-time and available through the Australian Ocean Data Network.
Marine heatwaves are extreme ocean climate events characterised by anomalously warm ocean temperatures that are prolonged in duration and extend over broad oceanic and coastal regions. A warming global climate and subsequent increase in ocean heat content will increase the frequency and potentially the severity of marine heatwaves, with significant ecological implications for species mortality, modification of species geographic range preferences and impacts on critical life history stages.
Marine heatwaves can be detected at the surface through remote sensing but understanding their subsurface extent in near real time is limited. There are regions in which cloud cover may be high and prevent an accurate understanding of the thermal anomalies over a broad coastal extent, or regions where the extremes temperature anomalies are restricted below the surface.
IMOS has set up a national steering committee who meet monthly to discuss a list of priority indicators, data sources, and tools for monitoring marine heatwaves through their growth, peak, and decay phases. The committee reviews and evaluates available evidence and indicators to assess the likelihood of marine heatwave events and the likely geographic regions to be impacted.
The committee develops a set of principles to aid in the prioritisation of the potential deployment locations and their timing of four IMOS Ocean glider deployments per annum. This priorisation is based on criteria including:
- predicted impacts including ecological consequences,
- scientific novelty of the marine heatwave,
- the potential consequences for aquaculture industries and the broader community,
- the availability of existing and supporting meteorological and
- oceanographic observations and models.
Prof. Charitha Pattiaratchi
Dr. Richard Brinkman