This project is one of a number that are in competition for funding from the NERC GW4+ DTP. The GW4+ DTP consists of the Great Western Four alliance of the University of Bath, University of Bristol, Cardiff University and the University of Exeter plus six Research Organisation partners. The partnership aims to provide a broad training in earth and environmental sciences, designed to train tomorrow’s leaders in earth and environmental science. For further details about the programme, please see http://nercgw4plus.ac.uk/
Model calibration is an important step for ensuring a realistic simulation of hydrological models and is typically performed using river discharge data. However, many of world’s river basins are poorly gauged, or the access to the data is limited. Besides, calibrating against discharge data does not necessarily guarantee a realistic estimation of flow dynamic and water storage, which is due to the equifinality problem with reasonable calibration fit but poor model predictions. These factors limit the application of available hydrological models to study water availability or climate change impact on water resources. During the last decades, satellite altimetry and gravity proved their high accuracy for monitoring surface water and terrestrial water storage, respectively. Although most of these data are freely available, only few studies apply them for calibrating hydrological models. Therefore, there is an urgent need for developing frameworks to use these data as extra constrains for calibrating hydrological models.
Project Aims and Methods
The central objective of this project is to design calibration frameworks to use satellite derived terrestrial water storage (TWS) and surface water level (SWL) data for calibrating hydrological models. It is our hypothesis that using these data in an efficient and flexible multi-criteria calibration approach reduces the equifinality problem and further improves model simulations. The hydrological model of the W3RA , which has not been calibrated against river discharge, will be used for simulations. Model validations will be performed over Australia, which is a data rich region, and the Niger River basin. The satellite data of this study include: (A) TWS from GRACE (2003- onwards) , and GRACE-FO (after 2018); and (B) SWL in rivers and reservoirs obtained by satellite altimetry missions from the European and American space agencies (1998-onwards) . Four multi-objective evolutionary algorithms of the NSGA-II, MPSO, PESA-II and SPEA-II, as well as a Combined objective function and Genetic Algorithm (CGA)  will be tested to simultaneously calibrate W3RA against river discharge, GRACE TWS and altimetry SWL. Bayesian techniques as in  will also be tested. We expect that the project will provide insights about daily to decadal water flow and storage changes in Australia and West Africa.
NERC GW4+ DTP funding is for 3.5 years and is open to UK and EU applicants who meet the residency eligibility criteria.
A studentship will provide UK/EU tuition fees, a stipend in line with the RCUK rate (£14,553 per annum for 2017/18) and a generous budget for research expenses and training.
For further information including additional details on eligibility criteria, funding and how to apply, please http://www.cardiff.ac.uk/study/postgraduate/funding/view/nerc-gw4-doctoral-training-partnership-phd-projects-in-the-school-of-earth-and-ocean-sciences
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