Natasha Wallum

Natasha is a Departmental Lecturer at the School of Geography and the Environment (SoGE) and tutor at Brasenose College. She is a physical geographer with research interests in aeolian geomorphology and desert dust emission.

Natasha holds a BSc (Hons) in Physical Geography and MSc in Applied GIS and Remote Sensing from the University of Southampton. During her studies, Natasha gained a keen interest in the application of geospatial analysis to dynamic geomorphology. Her passion for this particular field of research was underlined by her BSc independent research dissertation that modelled the effects of climate change and sea-level rise on complex soft cliff coastlines. This work received multiple prestigious national awards, including the Alfred Steers Dissertation Prize from the Royal Geographical Society (with IBG) and the Marjorie Sweeting Dissertation Award from the British Society for Geomorphology.

Prior to studying for her DPhil at the University of Oxford, Natasha worked as a corporate geospatial analyst in the City of London.

Natasha has recently completed her DPhil in Geography and the Environment, in association with the UKRI National Environment Research Council’s Doctoral Training Program (NERC-DTP) and Hertford College. Her DPhil research applied a combination of fieldwork experimentation, remote sensing analysis and laboratory methods to investigate the processes controlling emissions of atmospheric mineral aerosols from Etosha Pan, Namibia – a major southern-hemisphere dust source. Natasha’s work has involved collaborations with various international organisations, including NASA and the USGS.

Since completing her DPhil, Natasha has continued her involvement with ongoing projects in global dust emissions modelling and field/space imaging spectroscopy to analyse and interpret the surface geochemistry of large ephemeral lake beds in dryland regions.

Natasha's research interests are primarily focused on the global dust cycle, with emphasis on the geomorphological and hydrological processes that occur within arid basins.

Ephemeral lakes and dust emissions

Ephemeral lake beds are prominent sources of atmospheric mineral dust aerosols globally, but emissions from these landforms are characterised by considerable spatial and temporal variability. It has proven extremely difficult to resolve the complex relationships between multi-scale climatic conditions and surface drivers that control windblown dust emissions from these source regions. Such complexity introduces uncertainty in model predictions of atmospheric dust loading with subsequent imprecision in estimates of its impacts and interactions with other global scale processes in the Earth system, which have far-reaching implications for climate, ocean fertilisation, nutrient transport, air quality and human health.

Natasha's research focuses on deploying a range of remote sensing approaches to constrain the effect of gross changes in hydrology and surface erodibility dynamics on the emission of dust from major ephemeral lake dust sources in southern Africa. As part of this, her work also involves the application of global time-series of Earth observation (EO) data (e.g., MODIS, MSG-SEVIRI, Landsat, EMIT) and field spectroscopy for monitoring the geochemistry and surface morphology of ephemeral lake systems. In addition to in-situ field experimentation to investigate the local scale controls and processes of aeolian entrainment from specific highly emissive dust 'hot-spot' surfaces from within these source regions.

Her research has involved collaboration with: Professor Giles Wiggs (University of Oxford), Dr Robert Bryant (University of Sheffield), and Dr Richard Reynolds (USGS). Funding from the UK Research and Innovation (UKRI) Natural Environment Research Council (NERC).

Natasha contributes to the undergraduate Preliminary Examinations lectures on Geomorphology for the 'Earth System Processes' course. She also lectures on the 'Earth System Dynamics' core course and the 'Desert Landscapes and Dynamics' option for the Final Honours School.

Natasha is willing to offer advisory support for undergraduate and masters dissertations in the fields of geomorphology, climate, and hazards in arid regions, in addition to the application of remote sensing and GIS for data analysis and visualisation.

Natasha is an undergraduate tutor, graduate advisor and admissions interviewer at Brasenose College. She also delivers lectures and workshops in the UNIQ summer school access programme.