Research Interests
Global and regional GPS/GNSS geodesy; hydrological loading; ocean tide loading; Glacial Isostatic Adjustment; sea level change; precise GPS/GNSS positioning; reference frames; tropospheric water vapour; GPS/GNSS meteorology; Synthetic Aperture Radar (SAR) interferometry (InSAR); engineering deformation monitoring; crustal deformation; tectonics (especially Greece and Italy); earthquake cycle; post-seismic deformation; geophysical inverse theory.
See my Google Scholar profile.
Current Work
Using global geodesy to observe the seasonal water cycle and climate change.
Precise GPS geodesy to constrain models of glacial isostatic adjustment in Antarctica.
Global geodetic reference frames.
Ocean tide loading in the UK and worldwide.
Geodetic observations of the earthquake cycle and associated geophysical inverse theory.
Postgraduate Supervision
Current:
Mohamed Akl (2021-). Assessment and management of groundwater resources using integration of remote sensing and geographical information system (GIS).
Rebecca Guiney (2021-). Investigating the capabilities of multi-scale and multi-sensor geospatial data to monitor rapidly depleting groundwater resources in Delhi, India.
Rinrada Srikwanma (2021-). Multipath effects in multi-GNSS.
Completed:
Ahmed Mohammed (PhD, 2023): Impact of combining GPS and GLONASS for reference frame densification using PPP.
Marine Roger (PhD, 2022). Co- and post-seismic deformation of the 1999 Chi-Chi earthquake revealed by Earth Observations.
Majid Abbaszadeh (PhD, 2021). Multi-constellation GNSS estimation of ocean tide loading displacement.
Katarina Vardić (PhD, 2021). A GNSS velocity field for estimating tectonic plate motion and testing global glacial isostatic adjustment models.
Yasir Al-Husseinawi (PhD, 2019). Spaceborne InSAR for dam stability.
Reza Amouzgar (PhD 2017): High-performance tsunami modelling with modern GPU technology.
Philippa Cowles (PhD 2017): Sidereal filtering for multi-GNSS precise point positioning and deformation monitoring.
Ciprian Spatar (PhD 2016): Observability and estimation of geocentre motion using multi-satellite laser ranging.
Sam Webb (PhD 2015): Kinematic GNSS tropospheric estimation and mitigation over a range of altitudes
Grace Nield (PhD 2014): The effect of Late Holocene ice mass changes on glacial isostatic adjustment in West Antararctica
Mohammed Assiadi (PhD 2012): Enhancement of the accuracy of single epoch positioning for long baselines with application to structure deformation monitoring [co-supervisor]
David Booker (PhD 2012): Secular changes in Earth's shape and surface mass loading
Ian Thomas (PhD 2008): GPS estimates of sub-daily to decadal changes in Antarctic water vapour, 1995-2006
Ahmed Ragheb (PhD 2008): Filtered and semi-continuous single epoch GPS for deformation monitoring
Sofia Rontogianni (PhD 2007): Strain rates in Greece using GPS measurements from 1994-2000
Anna Freemantle (PhD 2006): Present-day Adriatic tectonics: rigorous tests using continuous GPS
Craig Allinson (PhD 2005): Ocean tide loading in the British Isles from GPS observations
Stuart Edwards (PhD 2005): GPS Calibration and Validation of Altimetric Satellite Radiometers
Jamal Gledan (PhD 2004): Development of low cost GPS strategies for deformation monitoring [co-supervisor]
Simon Edwards (PhD 2003): Calibration of tropospheric artefacts in SAR interferometry using GPS observations
Ravi Gunasingam (MPhil 2003): Single-epoch ambiguity resolution using low-cost GPS receivers
Julian Rainbow (MPhil 2001): Optimising navigational precision utilising potential GNSS constellations
Esteem Indicators
Advisory boards and committees:
UK delegate to International Association for Geodesy (2011-2018).
UK panel for International Union of Geodesy and Geophysics (2011-2018).
NERC Advisory Network (2019-).
Satellite Applications Catapult NE Centre of Excellence steering committee (2014-2023).
Board of Editors, Journal of Geodesy, 2007-2015.
British Geophysical Association committee (2009-2015; Treasurer 2011-2015).
Peer review panels:
NERC Earth Sector Services and Facilities Advisory Group (2014-2016).
NERC Peer Review College, 2008-present (Interdisciplinary Studentships peer review panel, 2010; Networks of Sensors moderating panel, 2011; New Investigators panel, 2011; Large Grants panel, 2013, 2016, 2017; Standard Grants panels, 2014, 2015); Panel A core member (2017-present); Exploring the Frontiers peer review panel (2022); Pushing the Frontiers moderating / peer review panel (2022); Global Partnerships Seedcorn Fund panel (2022).
NERC Geophysical Equipment Facility Steering Committee, 2005-2014 (Chair 2010-2014).
NERC Space Geodesy Steering Committee, 2004-2007.
NERC Services Review Board member, 2004.
NASA Inter-Disciplinary Science sea-level funding review panel member (2003); Earth Surface & Interior peer review panel (2019).
European Science Foundation review college (2008-present).
Keynote and invited presentations:
Invited speaker (x2), American Geophysical Union Fall conference, San Francisco, 2003.
Invited speaker, IERS workshop, Munich, 2002.
Invited keynote speaker, IGCP565 3rd workshop, Reno, 2010.
Invited speaker, WEGENER 17th General Assembly, Leeds, 2014.
Invited speaker, IUGG General Assembly, Prague, 2015.
Funding
UK Natural Environment Research Council:
Global geodetic investigation of widespread intraplate deformation (PI, 1999-2002).
Elastic and Inelastic Ocean Tide Loading Response in the British Isles from Long-term GPS Observations (PI, 2001-2004).
Solid Earth deformation and changes in mass transport of the hydrosphere (PI, 2002-2005).
Validation of GRACE gravity field determination using GPS (PI, 2003-2004).
Changes in Glacier Geometry and Extent in Svalbard: implications for Sea-level Rise During the 20th and 21st Centuries (Co-I, 2004-2007).
Global Loading and Deformation at Tidal Timescales (PI, 2006-2009).
Tidal Dynamics of the Filchner-Ronne and Larsen C Ice Shelves from GPs Observations and Model Assimilation (PI, 2007-2010).
The determination of a new global GPS-derived surface velocity field and its application to the problem of 20th century sea-level rise (Co-I, 2007-2011).
Improved constraints on global-scale hydrological change by determining secular geocenter motion and low degrees of the surface mass load (PI, 2008-2013).
Consistent multi-technique geodetic estimates of contributions to present-day sea level change (PI, 2008-2011).
Improved models of West Antarctic glacial isostatic adjustment through new crustal motion data (Co-I/PI, 2009-2015).
Resolving Antarctic ice mass TrEndS [RATES] (Co-I/PI, 2012-2015).
iSTAR-D: The contribution to sea level from the Amundsen Sea sector of Antarctica (Co-I/PI, 2013-2017).
Reducing the uncertainty in estimates of the sea level contribution from the westernmost part of the East Antarctic Ice Sheet [Undercoats] (PI, 2014-2020).
Tidal loading and asthenospheric anelasticity (PI, 2018-2024).
Quantifying West Antarctic mantle viscosity via precise GPS measurement of Earth's response to surface mass balance anomalies (Co-I, 2017-2025).
UK Engineering and Physical Sciences Research Council:
Correction of tropospheric artefacts in SAR interferograms using GPS observations (PI, 1999-2002).
Synergy of GPS, digital photogrammetry and InSAR for coastal zone monitoring (Co-I, 2000-2003).
Auto - bahn: Towards Millimetre Accurate Real - Time Positioning From GNSS (Co-I, 2005-2007).
Institutional Award equipment funding (PI, 2013).
Other academic or related bodies:
GPS subsidence monitoring at Houghton-le-Spring (British Geological Survey; PI, 2001-2002).
An assessment of ocean tide loading models for precise GPS positioning in Great Britain (RICS Education Trust; Co-I, 2005).
Tropospheric effects on GNSS positioning for airborne applications (RICS Education Trust; Joint PI, 2011).
Mitigation of GNSS multipath by the use of dual-polarisation observations (RICS Education Trust; Joint PI, 2013-2014).
Regional glacial isostatic adjustment and CryoSat elevation rate corrections in Antarctica [REGINA] (European Space Agency; PI, 2013-2014 and 2014-2015).
Industrial research and consultancy:
Continuous monitoring of North Sea oil platform movement using GPS (Shell UK; Co-I, 1998-2002; PI, 2003-2015).
Subsidence monitoring at Wytch Farm oil field, Dorset (BP; Co-I, 2002, 2004, 2006, 2010).
Review and validation of improvements to GPS subsidence monitoring at Ekofisk field, southern North Sea (Phillips Petroleum; PI, 2002-2003).
Permanent GPS Monitoring of Shah Deniz Platform, Caspian Sea (Fugro Survey / BP; Co-I, 2005-2014).
An examination of commercial network RTK GPS services in Great Britain (The Survey Association; Co-I, 2008).
Further examination of commercial network RTK GNSS services in Great Britain (The Survey Association; Co-I, 2011).
Reprocessing and analysis of offshore platform GNSS data (Hurricane Geo Inspection Survey / Petronas; PI, 2016).
Optimisation of the value and performance of PageNET (Ordnance Survey International / NAMRIA; PI, 2017).
Modernisation of GNSS Network RTK services in Guyana (Ordnance Survey International / GLSC; PI, 2018-19).
East of Leeds control survey validation (Central Alliance; PI, 2018).
Industrial Relevance
Precise positioning and navigation.
Oilfield and oil platform monitoring.
Engineering and natural hazard deformation monitoring.
