PALMER_UNOC18NEX - Turbulent breath: Observing the interplay of upper ocean fine structure and oxygen variability with autonomous ocean gliders
Turbulent breath: Observing the interplay of upper ocean fine structure and oxygen variability with autonomous ocean gliders
The exchange of gases between atmosphere and ocean is a topic of intense scientific interest due to its importance for global climate and oceanic ecosystems. Oxygen concentrations in surface waters are directly influenced by air-sea exchange and the subsequent transfer of oxygen to deeper layers has an important role to play in ventilating our oceans to maintain healthy and productive seas. Regions where ocean oxygen levels are depleted to potentially unhealthy levels are growing globally, both in the open-ocean and coastal areas (Diaz and Rosenberg, 2009), caused by changing temperatures, nutrient supply and atmospheric forcing. This has important and possibly dangerous implications for marine ecosystems and the potential to change global carbon cycles.
Many of the physical and biogeochemical mechanisms that regulate air-sea transfer of gases are determined by turbulent mixing. Turbulence is, however, chaotic and notoriously difficult to measure. New developments (Palmer et al., 2015) using autonomous ocean gliders provide improved capability in resolving fine-scale ocean structure and turbulence up to the sea surface that has the potential to enhance our understanding of gas exchange at this critical interface.
Data for this project come from shelf sea and open ocean sites including the Celtic Sea, Porcupine Abyssal Plain and the mid-Atlantic. The student will collect additional data in the framework of the NERC AlterEco project in the North Sea. Each dataset provides measurements of near surface finescale and microscale temperature and velocity by autonomous underwater gliders that allow quantifying turbulent mixing in the near surface layer and upper ocean thermocline. Combined with meteorological and surface measurements from autonomous Wavegliders and ship data, this studentship will investigate the links between variable meteorological and ocean forcing on air-sea gas transfer.
The student will process and analyse turbulence and other physical and biogeochemical data collected by state-of-the-art autonomous ocean vehicles, and develop expertise in air-sea gas transfer mechanisms and parameterisations. Combining this new dataset with models of the ocean surface mixed layer and meteorological data, the student will then develop an improved understanding of how changing weather, waves and ocean conditions impact on oxygen uptake to address the key question:
How will future climate impact on the turbulent transfer of oxygen and other gases between ocean and atmosphere?
The NEXUSS CDT provides state-of-the-art, highly experiential training in the application and development of cutting-edge Smart and Autonomous Observing Systems for the environmental sciences, alongside comprehensive personal and professional development. There will be extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial / government / policy partners. The student will be registered at the University of East Anglia, and hosted at the NOC in Liverpool. In addition to the training provided by NEXUSS the student will also benefit from the expertise of their supervisory team who will provide training in
- Data processing and analysis techniques relating to a wide range of ocean measurements including ocean microstructure (turbulence), gliders, ADCP and CTD.
- Understanding of air-sea gas transfer mechanisms and parameterisations.
- Development of ocean surface boundary layer models including coupling of atmosphere and oceans and gas-transfer.
This project has been shortlisted for funding by the NEXUSS Centre for Doctoral Training. Undertaking a PhD with the NEXUSS CDT will involve attendance at mandatory training events throughout the course of the PhD.
Selected candidates who meet RCUK’s eligibility criteria will be awarded a NERC/EPSRC studentship - in 2017/18, the stipend is £14,553.
In most cases, UK and EU nationals who have been resident in the UK for 3 years are eligible for a stipend. For non-UK EU-resident applicants NERC/EPSRC funding can be used to cover tuition fees, RTSG and training costs, but not any part of the stipend. Individual institutes may, however, elect to provide a stipend from their own resources.
This PhD studentship is expected to begin in September/October 2018. Both full-time and part-time study are possible (those planning to study part-time may wish to discuss this with the supervisor before applying).
1) Diaz, R. J., and R. Rosenberg (2008) Spreading dead zones and consequences for marine ecosystems. Science 321.5891 926-929.
2) M. R. Palmer et al (2015) Turbulence and Mixing by Internal Waves In The Celtic Sea Determined From Ocean Glider Microstructure Measurements. Journal of Marine Systems http://dx.doi.org/10.1016/j.jmarsys.2014.11.005
Prof Jan Kaiser (University of East Anglia)
Prof Mark Inall (The Scottish Association for Marine Science)
- Start date October 2018
- Studentship Length 3 years 8 months
- Acceptable First Degree any numerate discipline, Chemistry, Mathematics, Oceanography or Marine Science, or Physics
- Minimum Entry Standard 2:1 or equivalent