Long-term ‘hydrologic memory’ in tropical dryland areas

Simon Opie, who obtained his UCL Geography MSc in Climate Change in 2019, has now had the outcomes of his thesis published in the leading journal, Earth System Dynamics.

He used satellite observations (From the Gravity Recovery and Climate Experiment: GRACE) to analyse changes in groundwater storage for 14 large-scale tropical and sub-tropical aquifer systems, comparing them with patterns of rainfall.

The systems exhibited distinct climate-controlled responses, relationships of great value in conceptualising how climate variability and change affect groundwater, the largest globally distributed source of freshwater.

Simon’s research also suggests that long-term climate trends are the main driver of groundwater changes in drylands systems, rather than the seasonal variability that dominates humid regions. This difference between long and short ‘hydraulic memory’ in groundwater systems has important implications for their sensitivity to climate disturbances such as drought, and the impacts of human groundwater abstraction.

The resulting paper, Climate-groundwater dynamics inferred from GRACE and the role of hydraulic memory, was prepared with Simon’s thesis supervisors, including UCL Geography's Professor Richard Taylor and Dr Chris Brierley as well as Dr Mohammad Shamsudduha (now at Sussex University) and Dr Mark Cuthbert (Cardiff University).

Simon is to continue post-graduate study in UCL Geography in September through a Fellowship from the London NERC Doctoral Training Programme.

See

• GRACE