Robin Robertson | Xiamen University Malaysia (original) (raw)
Papers by Robin Robertson
Deep-sea Research Part Ii-topical Studies in Oceanography, Aug 1, 2022
Sound propagation in Australian waters is of keen interest to the Royal Australian Navy (RAN) and... more Sound propagation in Australian waters is of keen interest to the Royal Australian Navy (RAN) and the Maritime Division of the Royal Australian Air Force (RAAF) as it affects sonar performance in one of their prime operating regions. Off eastern Australia, temperature fields are affected by the East Australian Current (EAC), eddies generated by the EAC, and internal tides. The ocean’s temperature structure off eastern Australia can be divided into three basic regimes: the strong southward EAC region (24 o -28 o S), the EAC separation region (28 o -32 o S), and the ‘river’ of eddies region (32 o -38 o S) south of the separation zone. Although the internal tides in this region are small, they modify the sound speed profile, with the potential to affect acoustic propagation on time scales of the daily and twice daily tidal cycles and the 15-day spring-neap tidal cycle. A primitive-equation model (Regional Ocean Modelling System (ROMS)) with tidal forcing provided temperature and salini...
Scientific data, Jan 30, 2016
Since 2008, 26 glider missions have been undertaken along the continental shelf of southeastern A... more 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 valida...
CLIVAR is an international research programme dealing with climate variability and predictability... more CLIVAR is an international research programme dealing with climate variability and predictability on timescales from months to centuries. CLIVAR is a component of the World Climate Research Programme (WCRP). WCRP is sponsored by the World Meteorological Organization, the International Council for Science and the Intergovernmental Oceanographic Commission of UNESCO.
Journal of Geophysical Research: Oceans, 2018
High‐resolution measurements of the air‐ice‐ocean system during an October 2015 event in the Beau... more High‐resolution measurements of the air‐ice‐ocean system during an October 2015 event in the Beaufort Sea demonstrate how stored ocean heat can be released to temporarily reverse seasonal ice advance. Strong on‐ice winds over a vast fetch caused mixing and release of heat from the upper ocean. This heat was sufficient to melt large areas of thin, newly formed pancake ice; an average of 10 MJ/m2 was lost from the upper ocean in the study area, resulting in ∼3–5 cm pancake sea ice melt. Heat and salt budgets create a consistent picture of the evolving air‐ice‐ocean system during this event, in both a fixed and ice‐following (Lagrangian) reference frame. The heat lost from the upper ocean is large compared with prior observations of ocean heat flux under thick, multiyear Arctic sea ice. In contrast to prior studies, where almost all heat lost goes into ice melt, a significant portion of the ocean heat released in this event goes directly to the atmosphere, while the remainder (∼30–40%)...
Elementa: Science of the Anthropocene, 2015
We present the first densely-sampled hydrographic survey of the Amundsen Sea Polynya (ASP) region... more We present the first densely-sampled hydrographic survey of the Amundsen Sea Polynya (ASP) region, including a detailed characterization of its freshwater distributions. Multiple components contribute to the freshwater budget, including precipitation, sea ice melt, basal ice shelf melt, and iceberg melt, from local and non-local sources. We used stable oxygen isotope ratios in seawater (δ18O) to distinguish quantitatively the contributions from sea ice and meteoric-derived sources. Meteoric fractions were high throughout the winter mixed layer (WML), with maximum values of 2–3% (±0.5%). Because the ASP region is characterized by deep WMLs, column inventories of total meteoric water were also high, ranging from 10–13 m (±2 m) adjacent to the Dotson Ice Shelf (DIS) and in the deep trough to 7–9 m (±2 m) in shallower areas. These inventories are at least twice those reported for continental shelf waters near the western Antarctic Peninsula. Sea ice melt fractions were mostly negative, ...
Remote Sensing
Breaking internal tides and induced mixing are critical to shelf dynamics, including heat and mas... more Breaking internal tides and induced mixing are critical to shelf dynamics, including heat and mass exchanges. Spatiotemporal variability of internal tides and modulation factors for the southern East China Sea shelf were examined based on a combination of a three-month mooring velocity and satellite altimeter data. Semidiurnal and diurnal internal tides exhibited distinct temporal trends, with the semidiurnal internal tides enhanced by an order of magnitude during the latter half of the record, while the diurnal internal tides followed quasi spring-neap cycles with a generally stable intensity except for two specific periods of strengthening. These internal tides probably originated remotely over the shelf-slope area northeast of Taiwan. Time-varying stratification was the most important factor for the internal tidal magnitude. In addition, varying background currents influenced the diurnal critical latitude band, which explains the slightly enhanced diurnal internal tides during th...
Japan Geoscience Union, 2016
The water column structure of the ice shelf cavity outflow from under Pine Island Glacier and its... more The water column structure of the ice shelf cavity outflow from under Pine Island Glacier and its temporal variability were investigated using a hourly time series of yo-yo CTD and LADCP data collected over ~24 h at the southern end of the ice shelf front. The primary water types present over the continental shelf off Pine Island Bay were Circumpolar Deep Water (CDW), modified Circumpolar Deep Water (mCDW), Shelf Water (SW), and Ice Shelf Water (ISW). As CDW transited the shelf, it transitioned into cooler, mCDW. In the upper 200 m, ISW dominated within 100 km of the ice shelf and SW further offshore. Within Pine Island Bay, the water column was partitioned into two primary layers based on their behavior: an upper outflowing layer from 100 m to 450 m composed of ISW with a significant meltwater component, 1%–2%, over an inflowing layer from ~550 m to the sea bed composed of mCDW. Due to the small cavity extent, the outflowing water was warmer than the seawater freezing point. The up...
Geoscience Letters, 2019
Vertical mixing is important in the ocean for maintaining its stratification, redistributing temp... more Vertical mixing is important in the ocean for maintaining its stratification, redistributing temperature and salinity, distributing nutrients and pollutants, and the energy cascade. It plays a key role in ocean energy transport, climate change, and marine ecosystems. Getting the mixing right in ocean circulation and climate models is critical in reproducing ocean and climate physics. Ocean models, like the Regional Ocean Modeling System (Rutgers ROMS 3.4), provide several options for determining vertical mixing through the vertical mixing parameterization schemes. To evaluate which of these methods best reproduces realistic vertical mixing by internal tides, simulations of baroclinic tides generated by a seamount were performed using seven different vertical mixing parameterizations: Mellor-Yamada 2.5 (MY), Large-McWilliams-Doney’s Kpp (LMD), Nakanishi-Niino’s modification of Mellor-Yamada (NN), and four versions of Generic Length Scale (GLS). The GLS versions in ROMS 3.4 severely o...
Frontiers in Marine Science, 2019
Newman et al. The Southern Ocean Observing System time series of key variables, and delivers the ... more Newman et al. The Southern Ocean Observing System time series of key variables, and delivers the greatest impact from data to all key end-users. Although the Southern Ocean remains one of the least-observed ocean regions, enhanced international coordination and advances in autonomous platforms have resulted in progress toward sustained observations of this region. Since 2009, the Southern Ocean community has deployed over 5700 observational platforms south of 40 • S. Large-scale, multi-year or sustained, multidisciplinary efforts have been supported and are now delivering observations of essential variables at space and time scales that enable assessment of changes being observed in Southern Ocean systems. The improved observational coverage, however, is predominantly for the open ocean, encompasses the summer, consists of primarily physical oceanographic variables, and covers surface to 2000 m. Significant gaps remain in observations of the ice-impacted ocean, the sea ice, depths >2000 m, the air-ocean-ice interface, biogeochemical and biological variables, and for seasons other than summer. Addressing these data gaps in a sustained way requires parallel advances in coordination networks, cyberinfrastructure and data management tools, observational platform and sensor technology, twoway platform interrogation and data-transmission technologies, modeling frameworks, intercalibration experiments, and development of internationally agreed sampling standards and requirements of key variables. This paper presents a community statement on the major scientific and observational progress of the last decade, and importantly, an assessment of key priorities for the coming decade, toward achieving the SOOS vision and delivering essential data to all end-users.
Journal of Geophysical Research: Oceans, 2019
Journal of Geophysical Research: Oceans, 2018
Characterize the internal tides in the Indonesian Seas and determine how they may vary seasonally... more Characterize the internal tides in the Indonesian Seas and determine how they may vary seasonally and interannually as the thermocline structure changes. OBJECTIVES Our primary objective is to provide reliable estimates for the barotropic and baroclinic tides in the Indonesian Seas. We intend to determine: 1) specifically where in the Indonesian Seas baroclinic tides are generated and propagated, and, if time allows, 2) the effect of the seasonally and ENSO driven North Pacific versus South Pacific thermohaline structures on internal tide generation.
Iop Conference Series Earth and Environmental Science, 2010
The present rapid melting of the Pine Island Glacier (PIG) has been attributed to basal melting d... more The present rapid melting of the Pine Island Glacier (PIG) has been attributed to basal melting driven by the ocean. Specifically, this ocean melting is attributed to currents and tides pumping "warm" Circumpolar Deep Water (CDW) into the ice shelf cavity. To identify tidal activity in the region, an observational time series of yo-yo CTD (Conductivity, Temperature, and Depth) data
Deep-sea Research Part Ii-topical Studies in Oceanography, Aug 1, 2022
Sound propagation in Australian waters is of keen interest to the Royal Australian Navy (RAN) and... more Sound propagation in Australian waters is of keen interest to the Royal Australian Navy (RAN) and the Maritime Division of the Royal Australian Air Force (RAAF) as it affects sonar performance in one of their prime operating regions. Off eastern Australia, temperature fields are affected by the East Australian Current (EAC), eddies generated by the EAC, and internal tides. The ocean’s temperature structure off eastern Australia can be divided into three basic regimes: the strong southward EAC region (24 o -28 o S), the EAC separation region (28 o -32 o S), and the ‘river’ of eddies region (32 o -38 o S) south of the separation zone. Although the internal tides in this region are small, they modify the sound speed profile, with the potential to affect acoustic propagation on time scales of the daily and twice daily tidal cycles and the 15-day spring-neap tidal cycle. A primitive-equation model (Regional Ocean Modelling System (ROMS)) with tidal forcing provided temperature and salini...
Scientific data, Jan 30, 2016
Since 2008, 26 glider missions have been undertaken along the continental shelf of southeastern A... more 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 valida...
CLIVAR is an international research programme dealing with climate variability and predictability... more CLIVAR is an international research programme dealing with climate variability and predictability on timescales from months to centuries. CLIVAR is a component of the World Climate Research Programme (WCRP). WCRP is sponsored by the World Meteorological Organization, the International Council for Science and the Intergovernmental Oceanographic Commission of UNESCO.
Journal of Geophysical Research: Oceans, 2018
High‐resolution measurements of the air‐ice‐ocean system during an October 2015 event in the Beau... more High‐resolution measurements of the air‐ice‐ocean system during an October 2015 event in the Beaufort Sea demonstrate how stored ocean heat can be released to temporarily reverse seasonal ice advance. Strong on‐ice winds over a vast fetch caused mixing and release of heat from the upper ocean. This heat was sufficient to melt large areas of thin, newly formed pancake ice; an average of 10 MJ/m2 was lost from the upper ocean in the study area, resulting in ∼3–5 cm pancake sea ice melt. Heat and salt budgets create a consistent picture of the evolving air‐ice‐ocean system during this event, in both a fixed and ice‐following (Lagrangian) reference frame. The heat lost from the upper ocean is large compared with prior observations of ocean heat flux under thick, multiyear Arctic sea ice. In contrast to prior studies, where almost all heat lost goes into ice melt, a significant portion of the ocean heat released in this event goes directly to the atmosphere, while the remainder (∼30–40%)...
Elementa: Science of the Anthropocene, 2015
We present the first densely-sampled hydrographic survey of the Amundsen Sea Polynya (ASP) region... more We present the first densely-sampled hydrographic survey of the Amundsen Sea Polynya (ASP) region, including a detailed characterization of its freshwater distributions. Multiple components contribute to the freshwater budget, including precipitation, sea ice melt, basal ice shelf melt, and iceberg melt, from local and non-local sources. We used stable oxygen isotope ratios in seawater (δ18O) to distinguish quantitatively the contributions from sea ice and meteoric-derived sources. Meteoric fractions were high throughout the winter mixed layer (WML), with maximum values of 2–3% (±0.5%). Because the ASP region is characterized by deep WMLs, column inventories of total meteoric water were also high, ranging from 10–13 m (±2 m) adjacent to the Dotson Ice Shelf (DIS) and in the deep trough to 7–9 m (±2 m) in shallower areas. These inventories are at least twice those reported for continental shelf waters near the western Antarctic Peninsula. Sea ice melt fractions were mostly negative, ...
Remote Sensing
Breaking internal tides and induced mixing are critical to shelf dynamics, including heat and mas... more Breaking internal tides and induced mixing are critical to shelf dynamics, including heat and mass exchanges. Spatiotemporal variability of internal tides and modulation factors for the southern East China Sea shelf were examined based on a combination of a three-month mooring velocity and satellite altimeter data. Semidiurnal and diurnal internal tides exhibited distinct temporal trends, with the semidiurnal internal tides enhanced by an order of magnitude during the latter half of the record, while the diurnal internal tides followed quasi spring-neap cycles with a generally stable intensity except for two specific periods of strengthening. These internal tides probably originated remotely over the shelf-slope area northeast of Taiwan. Time-varying stratification was the most important factor for the internal tidal magnitude. In addition, varying background currents influenced the diurnal critical latitude band, which explains the slightly enhanced diurnal internal tides during th...
Japan Geoscience Union, 2016
The water column structure of the ice shelf cavity outflow from under Pine Island Glacier and its... more The water column structure of the ice shelf cavity outflow from under Pine Island Glacier and its temporal variability were investigated using a hourly time series of yo-yo CTD and LADCP data collected over ~24 h at the southern end of the ice shelf front. The primary water types present over the continental shelf off Pine Island Bay were Circumpolar Deep Water (CDW), modified Circumpolar Deep Water (mCDW), Shelf Water (SW), and Ice Shelf Water (ISW). As CDW transited the shelf, it transitioned into cooler, mCDW. In the upper 200 m, ISW dominated within 100 km of the ice shelf and SW further offshore. Within Pine Island Bay, the water column was partitioned into two primary layers based on their behavior: an upper outflowing layer from 100 m to 450 m composed of ISW with a significant meltwater component, 1%–2%, over an inflowing layer from ~550 m to the sea bed composed of mCDW. Due to the small cavity extent, the outflowing water was warmer than the seawater freezing point. The up...
Geoscience Letters, 2019
Vertical mixing is important in the ocean for maintaining its stratification, redistributing temp... more Vertical mixing is important in the ocean for maintaining its stratification, redistributing temperature and salinity, distributing nutrients and pollutants, and the energy cascade. It plays a key role in ocean energy transport, climate change, and marine ecosystems. Getting the mixing right in ocean circulation and climate models is critical in reproducing ocean and climate physics. Ocean models, like the Regional Ocean Modeling System (Rutgers ROMS 3.4), provide several options for determining vertical mixing through the vertical mixing parameterization schemes. To evaluate which of these methods best reproduces realistic vertical mixing by internal tides, simulations of baroclinic tides generated by a seamount were performed using seven different vertical mixing parameterizations: Mellor-Yamada 2.5 (MY), Large-McWilliams-Doney’s Kpp (LMD), Nakanishi-Niino’s modification of Mellor-Yamada (NN), and four versions of Generic Length Scale (GLS). The GLS versions in ROMS 3.4 severely o...
Frontiers in Marine Science, 2019
Newman et al. The Southern Ocean Observing System time series of key variables, and delivers the ... more Newman et al. The Southern Ocean Observing System time series of key variables, and delivers the greatest impact from data to all key end-users. Although the Southern Ocean remains one of the least-observed ocean regions, enhanced international coordination and advances in autonomous platforms have resulted in progress toward sustained observations of this region. Since 2009, the Southern Ocean community has deployed over 5700 observational platforms south of 40 • S. Large-scale, multi-year or sustained, multidisciplinary efforts have been supported and are now delivering observations of essential variables at space and time scales that enable assessment of changes being observed in Southern Ocean systems. The improved observational coverage, however, is predominantly for the open ocean, encompasses the summer, consists of primarily physical oceanographic variables, and covers surface to 2000 m. Significant gaps remain in observations of the ice-impacted ocean, the sea ice, depths >2000 m, the air-ocean-ice interface, biogeochemical and biological variables, and for seasons other than summer. Addressing these data gaps in a sustained way requires parallel advances in coordination networks, cyberinfrastructure and data management tools, observational platform and sensor technology, twoway platform interrogation and data-transmission technologies, modeling frameworks, intercalibration experiments, and development of internationally agreed sampling standards and requirements of key variables. This paper presents a community statement on the major scientific and observational progress of the last decade, and importantly, an assessment of key priorities for the coming decade, toward achieving the SOOS vision and delivering essential data to all end-users.
Journal of Geophysical Research: Oceans, 2019
Journal of Geophysical Research: Oceans, 2018
Characterize the internal tides in the Indonesian Seas and determine how they may vary seasonally... more Characterize the internal tides in the Indonesian Seas and determine how they may vary seasonally and interannually as the thermocline structure changes. OBJECTIVES Our primary objective is to provide reliable estimates for the barotropic and baroclinic tides in the Indonesian Seas. We intend to determine: 1) specifically where in the Indonesian Seas baroclinic tides are generated and propagated, and, if time allows, 2) the effect of the seasonally and ENSO driven North Pacific versus South Pacific thermohaline structures on internal tide generation.
Iop Conference Series Earth and Environmental Science, 2010
The present rapid melting of the Pine Island Glacier (PIG) has been attributed to basal melting d... more The present rapid melting of the Pine Island Glacier (PIG) has been attributed to basal melting driven by the ocean. Specifically, this ocean melting is attributed to currents and tides pumping "warm" Circumpolar Deep Water (CDW) into the ice shelf cavity. To identify tidal activity in the region, an observational time series of yo-yo CTD (Conductivity, Temperature, and Depth) data