Using high-resolution ocean timeseries data to give context to long term hydrographic sampling off Port Hacking, NSW, Australia

Through the development of the NSW node of the Australian Integrated Marine Observing System (NSW-IMOS). A mooring array of 4 moorings has been developed off the coast of Sydney, Australia, providing more than 2 years of timeseries data on the Sydney shelf. Parameters measured include velocity and temperature, salinity, fluorescence, dissolved oxygen and turbidity. This moored timeseries data complements the more than 70 year time series (since 1942) of physical sampling at the Port Hacking (Sydney, Australia) 50 m and 100 m sites, by providing spatial and temporal context. In this paper we investigate the relationship between the monthly vertical CTD profiles and the high temporal resolution moored timeseries, specifically the sub-monthly variability in the temperature and salinity observations. For the first time we have a timeseries of optical signals at two sites which can be used to give spatial and temporal context to the monthly biogeochemical and phytoplankton record from the physical samples. We assess the significance of sub monthly variability relative to the annual signal. We also identify issues with the optical signals obtained from the Wetlabs WQMS that appear as a result of moving to an operational phase of the program where instruments are rotated frequently.