Emissions of mineral dust into the atmosphere from land surfaces susceptible to wind erosion are highly significant for understanding the Earth’s environmental system as a whole. Appreciation of the wide ranging environmental influence that dust exerts is such that a full “dust cycle” concept - its uplift, through atmospheric residence time, to eventual deposition - is now recognised. Suspended dust can have a role in controlling climate by influencing incoming solar radiation, and affect global biogeochemical cycles, for instance, by providing nutrient fertilisation to oceans and triggering phytoplankton responses which cause atmospheric CO2 drawdown.
The initial process of dust emission from the surface must be well understood because this stage of the cycle is fundamental for the spatial and temporal variability of atmospheric dust loading, and therefore, is a primary control on the environmental effects dust might have. Recently, sources of dust located in the high latitudes (≥50°N and ≥40°S) have emerged as a potentially significant contributor of dust to the global system. While process studies have been undertaken in low latitude, dryland environments, measurements of dust flux and the controls on this from both the land surface and the boundary-layer airflow, are largely absent from high latitude dust areas. The lack of knowledge concerning high latitude dust emission processes means that key uncertainties also exist regarding the relative importance of different drivers between the low and high latitudes.
Computer modelling approaches are the best way to understand the complex impacts of dust, but a key limitation of existing dust models remains their accuracy in simulating the initial raising of dust. To predict atmospheric loading, models must be able to correctly quantify the amount of dust emitted from the land surface. To improve modelling performance, field-based measurements of dust production rates and the micrometeorological factors that drive them are needed from process experiments conducted on surfaces prone to emission. Dust emission in the high latitudes is particularly lacking in this regard, where a robust dataset of emission and its related drivers will have a valuable role in parametrizing current dust emission schemes for use in high latitudes.
Fieldwork in the high latitudes will be essential for this project. Field campaigns in the Søndre Strømfjord valley near Kangerlussuaq, West Greenland, will be undertaken at times of reliable, peak dust emission in the region. A full suite of micrometeorological variables, together with vertical dust flux (the fundamental measurement of dust emission from the surface), will be quantified on actively eroding surfaces. Changing surface conditions including moisture, saltation activity and fine sediment characteristics will also be determined, as well as local dust deposition rates.
Work with the project collaborator will add a modelling component to the project. The field datasets of measured vertical dust fluxes and rates of deposition can be used to first evaluate and then constrain existing dust models as a first step to improving dust modelling in high latitudes. The benefit of detailed sedimentological input for model performance will also be tested.
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.
Training will be provided in logistics planning for fieldwork, and field sampling. The student will also develop familiarity with all equipment, including datalogging skills that are broadly applicable across environmental monitoring. Analysis of a range of varied, complementary datasets will also lead to high-order computational skills. The opportunity to work with numerical dust emission schemes will enable the student to become proficient in modelling techniques.
Year 1: Planning and preparation for a first field season in late Spring, timed with peak dust emissions. Analysis and interpretation of initial dataset and field samples.
Year 2: Applying Year 1 dataset to existing dust models. Design and execution of second field season, with a particular focus on data requirements for improved dust emission modelling in high latitudes.
Year 3: Detailed analysis, integration and interpretation of both field datasets, leading to refinement of dust emission schemes for accurate simulation of dust production at high latitudes.
Partners and collaboration (including CASE)
Through working in SW Greenland, the student would be eligible to become involved in and seek support from the study region-focussed multi-disciplinary Kangerlussuaq International Research Network (KAIRN) and the broader, global High Latitude and Cold Climate Dust Network. Both are highly active groups of international researchers that meet regularly.
To integrate the field data with dust models, there will be the excellent opportunity to collaborate with Dr Kerstin Schepanski, an internationally renowned dust modeller at the Leibniz Institute for Tropospheric Research (TROPOS), Leipzig, Germany.
For information about this project, please contact Prof. Joanna Bullard (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/.