Mean hydrography on the continental shelf from 26 repeat glider deployments along Southeastern Australia

Abstract

Since 2008, 26 glider missions have been undertaken along the continental shelf of southeastern Australia. Typically these missions have spanned the continental shelf on the inshore edge of the East Australian Current from 29.5–33.5°S. This comprehensive dataset of over 33,600 CTD profiles from the surface to within 10 m of the bottom in water depths ranging 25–200 m provides new and unprecedented high resolution observations of the properties of the continental shelf waters adjacent to a western boundary current, straddling the region where it separates from the coast. The region is both physically and biologically significant, and is also in a hotspot of ocean warming. We present gridded mean fields for temperature, salinity and density, but also dissolved oxygen and chlorophyll-a fluorescence indicative of phytoplankton biomass. This data will be invaluable for understanding shelf stratification, circulation, biophysical and bio-geochemical interactions, as well as for the validation of high-resolution ocean models or serving as teaching material.

Subsurface intensification of marine heatwaves off southeastern Australia: The role of stratification and local winds

“…This subsurface intensity maximum is in agreement with previously observed heat damage to benthic species, such as coral, kelp, and seagrass [ Poloczanska et al , ; Wernberg et al , ; Marzinelli et al , ; Thomson et al , ]. In addition, we can expect an influence of these extreme temperature anomalies on phytoplankton growth, as the deep chlorophyll a maximum is often observed around the depth of greatest MHW intensity [e.g., Schaeffer et al , ] and the time scale required for phytoplankton to double their size is of the same order as the duration of MHW events (days) [ Denman and Powell , ]. While the direct effect of temperature on phytoplankton productivity is still under debate, most studies agree on a significant thermal influence when no other factor is limiting (e.g., nutrients and light) [ Huertas et al , ; Edwards et al , ].…”

OceanGliders: A Component of the Integrated GOOS

“…The progress of gliders in moving from a developing to a mature technology is exemplified by the programs that have been run continuously for over 10 years, for example, in the California Current (Adams et al, 2016;Rudnick et al, 2017), and the Solomon Sea (Davis et al, 2012). Long-term observations lasting several years are becoming widespread (Heslop et al, 2012;Schaeffer et al, 2016a;Yu et al, 2017;Du Plessis et al, 2019). The capability to sustain these programs relies on the improved dependability of gliders (Brito et al, 2014;Rudnick et al, 2016a;Brito and Griffiths, 2018) and the experience, skill and confidence of the operators.…”

“…A fourth line off northern California has been occupied for 2 years (Figure 6M). • The inshore edge of the East Australian Current (EAC) has had repeated sections run since 2010 ( Figure 6E) to observe the separation of the current, and the momentum balance at that point (Schaeffer and Roughan, 2015), the hydrographic structure of the current (Schaeffer et al, 2016a), the biogeochemistry (Schaeffer et al, 2016b). • Sections across the California Current, immediately south of the West Wind Drift bifurcation region, were occupied continuously from 2003 to 2009, and then annually, for 6-9 months per year, from 2010 to 2015 (Figures 6F,G).…”

Shelf and Coastal Ocean Observing and Modeling Systems: A New Frontier in Operational Oceanography

“…The data have been released publically in a gridded dataset (Schaeffer et al, 2016a) and are an invaluable resource with which to understand shelf circulation dynamics , stratification (Schaeffer et al, 2016b, Schaeffer and, biophysical and biogeochemical interactions (Baird et al, 2011;Everett et al, 2015;Schaeffer et al, 2016b). They are also useful for data assimilation into and validation of high-resolution ocean models (Kerry et al, 2016).…”