The long-term vision that has underlain the proposal to IMOS for the “Radiometry Task Team” (RTT)... more The long-term vision that has underlain the proposal to IMOS for the “Radiometry Task Team” (RTT), whose work is summarised in this report, is as follows. We think that the Australian research community involved into ocean colour and bio-optics science has the potential to become a major player in the Southern hemisphere in the coming years. We want to play this role by providing crucial validation data to the upcoming global satellite missions (Sentinels in particular), by delivering satellite products tailored to the needs of Australian researchers, institutions and users, and by improving practices and knowledge of our community in the domain of fieldwork in optics. The Australian Government has now an agreement with the European Commission (EC), signed by Geosciences Australia (GA) on hosting the collaborative Ground Segment for the Sentinel system. This agreement was, amongst other reasons, reached on the understanding that Australia would deliver world-class calibration –validation data back to the EC, the European Space Agency (ESA) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). This will be feasible by building on the investments of the past 10 years, by taking advantage of the next slice of NCRIS funding to leverage co-contributions, and also by reorganizing significantly our assets and activities. International engagement will also be key to success here, for instance through the validation teams of global mission, the IOCCG, the building of international research proposals. We hope that the present report shows how the RTT has achieved a first step in that direction and, above all, has allowed a community plan to be put together for the coming years.
This review represents the Southern Ocean community's satellite data needs for the coming decade.... more This review represents the Southern Ocean community's satellite data needs for the coming decade. Developed through widespread engagement and incorporating perspectives from a range of stakeholders (both research and operational), it is designed as an important community-driven strategy paper that provides the rationale and information required for future planning and investment. The Southern Ocean is vast but globally connected, and the communities that require satellite-derived data in the region are diverse. This review includes many observable variables, including sea ice properties, sea surface temperature, sea surface height, atmospheric parameters, marine biology (both micro and macro) and related activities, terrestrial cryospheric connections, sea surface salinity, and a discussion of coincident and in situ data collection. Recommendations include commitment to data continuity, increases in particular capabilities (sensor types, spatial, temporal), improvements in dissemination of data/ products/uncertainties, and innovation in calibration/validation capabilities. Full recommendations are detailed by variable as well as summarized. This review provides a starting point for scientists to understand more about Southern Ocean processes and their global roles, for funders to understand the desires of the community, for commercial operators to safely conduct their activities in the Southern Ocean, and for space agencies to gain greater impact from Southern Ocean-related acquisitions and missions.
Remote sensing of Southern Ocean chlorophyll concentrations is the most effective way to detect l... more Remote sensing of Southern Ocean chlorophyll concentrations is the most effective way to detect large-scale changes in phytoplankton biomass driven by seasonality and climate change. However, the current algorithms for the Sea-viewing Wide Field-of-view Sensor (SeaWiFS, algorithm OC4v6), the Moderate Resolution Imaging Spectroradiometer (MODIS-Aqua, algorithm OC3M) and GlobColour significantly underestimate chlorophyll concentrations at high latitudes. Here we use a long-term dataset from the Southern Ocean (20 - 160E) to develop more accurate algorithms for all three of these products in southern high latitude regions. These new algorithms improve in situ versus satellite chlorophyll coefficients of determination (r^2) from 0.27 to 0.46, 0.26 to 0.51 and 0.25 to 0.27, for OC4v6, OC3M and GlobColour, respectively, while addressing the underestimation problem. This study also revealed that pigment composition, which reflects species composition and physiology, is key to understanding the reasons for satellite chlorophyll underestimation in this region. These significantly improved algorithms will permit more accurate estimates of standing stocks and more sensitive detection of spatial and temporal changes in those stocks, with consequences for derived products such as primary production and carbon cycling.
All photosynthetic organisms endeavor to balance energy supply with demand. For sea-ice diatoms, ... more All photosynthetic organisms endeavor to balance energy supply with demand. For sea-ice diatoms, as with all marine photoautotrophs, light is the most important factor for determining growth and carbon-fixation rates. Light varies from extremely low to often relatively high irradiances within the sea-ice environment, meaning that sea-ice algae require moderate physiological plasticity that is necessary for rapid light acclimation and photoprotection. This study investigated photoprotective mechanisms employed by bottom Antarctic sea-ice algae in response to relatively high irradiances to understand how they acclimate to the environmental conditions presented during early spring, as the light climate begins to intensify and snow and sea-ice thinning commences. The sea-ice microalgae displayed high photosynthetic plasticity to increased irradiance, with a rapid decline in photochemical efficiency that was completely reversible when placed under low light. Similarly, the photoprotective xanthophyll pigment diatoxanthin (Dt) was immediately activated but reversed during recovery under low light. The xanthophyll inhibitor dithiothreitol (DTT) and state transition inhibitor sodium fluoride (NaF) were used in under-ice in situ incubations and revealed that nonphotochemical quenching (NPQ) via xanthophyll-cycle activation was the preferred method for light acclimation and photoprotection by bottom sea-ice algae. This study showed that bottom sea-ice algae from the east Antarctic possess a high level of plasticity in their light-acclimation capabilities and identified the xanthophyll cycle as a critical mechanism in photoprotection and the preferred means by which sea-ice diatoms regulate energy flow to PSII.
Hobart has the highest number of scientists per capita of any city in Australia. We all use data ... more Hobart has the highest number of scientists per capita of any city in Australia. We all use data and we can all learn from each other.
I started Data Science Hobart in order to build a community of scientists, programmers, data monkeys, and hackers that meet regularly, in Hobart, to discuss data, concepts, tools, methods, and to solve problems. The group will try to be programming language independent – we should feel free to talk about any programming language or problem – including R, Matlab, Python, Java, Excel or whatever you happen to use.
This group is open to all and our meetings are usually held in the IMAS Waterfront Building, 20 Castray Esplanade, Battery Point.
Uploads
Papers by Robert Johnson
We think that the Australian research community involved into ocean colour and bio-optics science has the potential to become a major player in the Southern hemisphere in the coming years. We want to play this role by providing crucial validation data to the upcoming global satellite missions (Sentinels in particular), by delivering satellite products tailored to the needs of Australian researchers, institutions and users, and by improving practices and knowledge of our community in the domain of fieldwork in optics.
The Australian Government has now an agreement with the European Commission (EC), signed by Geosciences Australia (GA) on hosting the collaborative Ground Segment for the Sentinel system. This agreement was, amongst other reasons, reached on the understanding that Australia would deliver world-class calibration –validation data back to the EC, the European Space Agency (ESA) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).
This will be feasible by building on the investments of the past 10 years, by taking advantage of the next slice of NCRIS funding to leverage co-contributions, and also by reorganizing significantly our assets and activities. International engagement will also be key to success here, for instance through the validation teams of global mission, the IOCCG, the building of international research proposals.
We hope that the present report shows how the RTT has achieved a first step in that direction and, above all, has allowed a community plan to be put together for the coming years.
Talks by Robert Johnson
I started Data Science Hobart in order to build a community of scientists, programmers, data monkeys, and hackers that meet regularly, in Hobart, to discuss data, concepts, tools, methods, and to solve problems. The group will try to be programming language independent – we should feel free to talk about any programming language or problem – including R, Matlab, Python, Java, Excel or whatever you happen to use.
This group is open to all and our meetings are usually held in the IMAS Waterfront Building, 20 Castray Esplanade, Battery Point.
Check us out here: [ http://datasciencehobart.wordpress.com/ ]
Sign up to the email list here: [ http://tinyletter.com/datasciencehobart ]
Write to us on Facebook here: [ https://www.facebook.com/datasciencehobart ]