Hydrodynamic Drivers of the 2013 Marine Heatwave on the North West Shelf of Australia

Abstract

A marine heatwave (MHW) occurs when ocean temperatures are warmer than a local threshold for an extended period of time (Hobday et al., 2016). This can occur off the coast of western Australia because of abnormal warming of the ocean surface driven by a Ningaloo Niño, the dominant climate variability mode in the southeastern Indian Ocean. In the austral summer of 2012/2013 a particularly strong MHW developed on Australia's North West Shelf (NWS) region (Figure 1), beginning in December 2012 and peaking in February 2013 (Feng et al., 2015; Xu et al., 2018). This MHW resulted in warm sea surface temperature (SST) anomalies during January and February of over 3°C that were mostly confined northeast of the North West Cape (NWC, Figure 1) in the southwestern region of the NWS (Xu et al., 2018). The MHW caused coral bleaching and other significant ecological impacts (Feng et al., 2015; Xu et al., 2018), stressing the importance of understanding the driving mechanisms behind the evolution of this strong MHW event. Ningaloo Niño, a key driver of MHWs in the region, usually starts to develop in September-October and peaks off the west Australian coast in the middle of the Australian summer in

Intercomparison of High‐Resolution SST Climatologies Over the Australian Region

“…Two relatively well-studied MHW cases were selected to illustrate the impact of different climatology and SST data sets on the daily SST anomalies. They are the 2013 marine heat wave over the North West Shelf of Australia (Maggiorano et al, 2021) and the 2015/2016 Tasman Sea marine heat wave (Oliver et al, 2017). One day during the peak period of each MHW event is selected and plotted.…”

“…Meteorological data analyses, using a comprehensive ocean-atmosphere data set and in situ data, are used to evaluate their potential contribution to the comparison results. Additionally, we compared two case studies of MHW events that are well studied by Maggiorano et al (2021) and Oliver et al (2017) to illustrate the possible uncertainty of MHW observation that is introduced by using different SST products and corresponding climatologies.…”