A 60+ year ocean temperature climatology for identifying extremes

The oceans are warming globally as a result of anthropogenic climate change. Long term temperature records are essential for detecting and providing context to oceanic warming and extreme events, which have disastrous effects on ocean ecosystems, causing mass mortality and habitat shifts. Ocean temperature has been measured between the surface and 100 m depth at the Port Hacking national reference station (South of Sydney, Australia) since 1953. A daily climatology of temperature statistics has been produced using measurements at this site, allowing the identification of subsurface temperature extremes over a period of more than 60 years. We present the methodology for creating the climatology, a unique method of validation, and highlight the challenges faced when combining big data sets collected over long timescales. We provide a consistent methodology with which other climatologies can be produced from similarly long combined datasets worldwide.