The Arctic is experiencing rapid warming, changes in the balance of snowfall and rainfall and a loss of snow- and glacier cover. Consequently, shifts in the amount and timing of freshwater runoff to fjords and their surrounding oceans are taking place. But because the Arctic is still so sparsely-measured, documenting such changes and their impact on the water cycle and supply of sediment to the glacier-fed fjords remains challenging, reducing confidence in the prediction of their effects. Nevertheless, this little-measured freshwater runoff is a critical input to the marine environment, and changes in it are likely to drive changes in sediment transfer and glacimarine sedimentation and coastal circulation. Determining patterns and changes of freshwater runoff and sediment input to fjords is therefore an important priority for understanding and forecasting environmental change in the wider Arctic, particularly considering the prospect of continued and accelerating future change.
This project focuses on the contribution of freshwater and suspended sediment transfer from onshore sources to an Arctic fjord system in Svalbard, their subsequent behaviour as they mix with fjord waters, and the tools that are best able to measure and monitor variability in them. The key features that this project will focus on are the buoyant sediment plumes that form as turbid runoff enters the fjord, either at its surface through subaerial rivers, or below the surface from submarine meltwater outlets at tidewater glacier faces as they provide an accessible means of measuring freshwater output from the watershed around the fjord. These turbid plumes are thought to be the main way that glaciers supply sediment to the glacimarine environment in polar climatic settings so Svalbard fjords lie at the meltwater-dominant end of the glacimarine-process continuum. However, detailed spatial and temporal observations of meltwater plume characteristics and behaviour as well as the volumes and fluxes of sediment that they deliver to Svalbard fjords are still lacking.
In this project you will investigate turbid plumes discharging from tidewater glaciers and subaerial rivers into a Svalbard fjord using combined in-situ oceanographic and geomorphological and remote approaches. The key project outcome is to gain significant insights into the changing freshwater contribution and sediment supply to a high Arctic fjord by addressing two project aims: (1) quantifying spatial and temporal variability of turbid meltwater plumes and sediment supply in order to determine how the plumes respond to meltwater and sediment inputs, how they interact with fjord circulation and meteorological forcing, and how the characteristics of the plumes can be used to derive useful information about meltwater runoff and sediment transfer. (2) Up-scaling plume variability results to whole fjord-scale in order to evaluate the synoptic hydrology and sediment supply of fast-changing Svalbard watersheds.
You will collect spatio-temporal oceanographic, sedimentological and small Unmanned Aircraft System (UAS; ‘drone’) data from a Svalbard fjord with an emphasis on meltwater plumes in coastal-margin and glacier-proximal to -distal locations. In-situ sampling of total suspended sediment (TSS) and spectral reflectance will be conducted on meltwater plumes to establish a turbidity-reflectance empirical relationship.
Temperature, conductivity and turbidity profiling, Acoustic Doppler Current Profiling (to depth range of 6 m) and water-column sampling will be used to define the oceanography of the fjord and the vertical structure of the plumes, specifically the thickness, extent and volume of the surface freshwater layer and TSS variation with depth, in order to quantify sediment flux within each plume and its temporal variability. Sediment traps will be used to derive plume sedimentation rates in proximal to distal locations for a variety of temporal scales. Spatial and temporal patterns of TSS for the whole plume will be derived by integrating in-situ measurements with drone-acquired imagery and spectral reflectance data.
The field measurements will be integrated with available climate and meteorological data and modelled estimates of freshwater runoff inputs. You will integrate plume data with MODerate resolution Imaging Spectroradiometer (MODIS) imagery from Terra and Aqua satellites to obtain a longer temporal record of meltwater plume behaviour and sediment flux since 2002 and use this as a basis to upscale results to a synoptic or fjord spatial scale.
Training and Skills
CENTA students are required to complete 45 days training throughout their PhD including a 10 day placement. In the first year, students will be trained as a single cohort on environmental science, research methods and core skills. Throughout the PhD, training will progress from core skills sets to master classes specific to CENTA research themes. You are required to be physically fit to undertake field work in potentially poor conditions.
A background in Earth sciences, geography or oceanography will be advantageous and you should have some experience of working with spatial datasets. Training will include processing and analysing spatio-temporal data and imagery derived from ocean instruments, sUAS and satellite. You will be trained and become qualified to operate a sUAS. Training will also be provided in relation to the design and collection of a high-quality oceanographic, geomorphological and sUAS data set. This training and the methodological approach will develop key skills identified by NERC as ‘most wanted’ for jobs in the environment sector such as multi-disciplinarity, fieldwork and numeracy.
Year 1: As fieldwork in Svalbard will not be possible until the summer of 2019, the initial period of the studentship will focus on learning about glacier-ocean interactions and hydrology, and analysing oceanographic and remotely sensed data. Assess satellite imagery to examine meltwater plume activity in Svalbard fjords. The fieldwork is planned to take place in the summer of 2019.
Year 2: Processing and analysis of sUAS imagery and spectral-reflectance data combined with in-situ oceanographic, sediment and spectral-reflectance sampling of meltwater plumes. An additional field season could be possible in 2020.
Year 3: Continue with data analysis and complete the write-up of the PhD project
Partners and collaboration (including CASE)
Dr Jeffrey Evans has over 20 years of experience of working on the glacimarine sedimentation processes close to polar tidewater glacier margins, including from meltwater plumes. Dr Richard Hodgkins has spent over 25 years working on the hydrology of High Arctic glaciers and meltwater discharged into Svalbard fjords. The student will also work with Dr Mark Brandon who has over 25 years of research experience of polar oceanography and oceanographic fieldwork. Dr David Graham has extensive experience of using drones, drone-sensors and geospatial data.
For information about this project, please contact Dr Jeffrey Evans (firstname.lastname@example.org) or Dr Richard Hodgkins (email@example.com). For enquiries about the application process, please contact the School of Social, Political and Geographical Sciences Research (firstname.lastname@example.org). Please quote CENTA when completing the application form: http://www.lboro.ac.uk/study/apply/research/.