Staff Profile

Introduction

Peter Clarke works at the interface of geodesy and geophysics, using precise GPS/GNSS positioning to study the deformation of the Earth due to plate tectonics, tides, and surface mass loading. His interests span the applications of these areas to geohazards such as earthquakes, tsunamis and climate change (changes in the global hydrological cycle, ice sheet mass, and atmospheric water vapour).

See also my Google Scholar profile, and open-access publications in the Newcastle University Library repository, or follow me on Twitter @geophysgeodesy .

Roles and Responsibilities

Deputy Director of Civil & Geospatial Engineering, 2021-present.

Qualifications

B.A. (Hons.), Natural Sciences (Geological Sciences), Queens' College, Cambridge University, 1992 (M.A., 1995).

D.Phil., Earth Sciences, Exeter College, Oxford University, 1997.

Certificate in Teaching and Learning in Higher Education, Newcastle University, 1999.

Disciplinary area

Geospatial Engineering

Previous Positions

Reader in Geophysical Geodesy, School of Civil Engineering and Geosciences, Newcastle University, 2004-2007.

Visiting Assistant Professor, Colorado Center for Astrodynamics Research and Department of Physics, University of Colorado at Boulder, USA, 2003 (sabbatical).

Lecturer, Department of Geomatics / School of Civil Engineering and Geosciences, Newcastle University, 1998-2004.

Junior Research Fellow, Wolfson College, Oxford University, 1997-1998.

Post-Doctoral Research Assistant, Dept. of Earth Sciences, Oxford University, 1996-1998.

Post-Graduate Research Assistant, Dept. of Earth Sciences, Oxford University, 1992-1993.

Memberships

Fellow, Royal Astronomical Society (2002-).

Fellow, Higher Education Academy (formerly ILTHE, 2001-).

Board of Editors, Journal of Geodesy (2007-2015).

UK panel for International Union of Geodesy and Geophysics (2011-2019).

British Geophysical Association (committee member 2009-2015, Treasurer 2011-2015).

NERC Peer Review College (2008-)

Member, American Geophysical Union (1998-).

Associate Member, International GNSS Service (1999-).

Associate, UNAVCO Inc (2009-).

Languages

English: fluent.

American: fluent.

Geordie: conversational.

French: basic conversational.

German: very basic.

Greek: very basic.

Informal Interests

Mountaineering, running, orienteering, cycling, skiing, travel, family.

Google scholar: click here.

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.

Undergraduate Teaching

CEG1711 "Tutorial study skills for geomatics".

CEG2710 "GNSS theory and practice" (module leader).

CEG2720 "Geomatics practice and research" (module leader).

CEG3707 "Geohazards and deformation monitoring" (module leader).

CEG3710 "Offshore surveying".

CEG3799 "Individual research project" (module leader).

• Articles

  • Koulali A, Whitehouse PL, Clarke PJ, van den Broeke MR, Nield GA, King MA, Bentley MJ, Wouters B, Wilson T. GPS-Observed Elastic Deformation Due to Surface Mass Balance Variability in the Southern Antarctic Peninsula. Geophysical Research Letters 2022, 49(4), e2021GL097109.
  • Vardić K, Clarke PJ, Whitehouse PL. A GNSS velocity field for crustal deformation studies: The influence of glacial isostatic adjustment on plate motion models. Geophysical Journal International 2022, 231(1), 426-458.
  • Koulali A, Clarke PJ. Modelling quasi-periodic signals in geodetic time series using Gaussian Processes. Geophysical Journal International 2021, 226(3), 1705-1714.
  • Nicolas J, Verdun J, Boy J-P, Bonhomme L, Asri A, Corbeau A, Berthier A, Durand F, Clarke P. Improved hydrological loading models in South America: analysis of GPS displacements using M-SSA. Remote Sensing 2021, 13(9), 1605.
  • Roger M, Li Z, Clarke P, Song C, Hu J-C, Feng W, Yi L. Joint inversion of geodetic observations and relative weighting-the 1999 Mω 7.6 chi-chi earthquake revisited. Remote Sensing 2020, 12(19), 3125.
  • Koulali A, Clarke PJ. Effect of antenna snow intrusion on vertical GPS position time series in Antarctica. Journal of Geodesy 2020, 94(10), 101.
  • Abbaszadeh M, Clarke PJ, Penna NT. Benefits of combining GPS and GLONASS for measuring ocean tide loading displacement. Journal of Geodesy 2020, 94, 63.
  • Wang J, Penna NT, Clarke PJ, Bos MS. Asthenospheric anelasticity effects on ocean tide loading around the East China Sea observed with GPS. Solid Earth 2020, 11, 185-197.
  • Clarke PJ. Seasonal Surface Loading Helps Constrain Short‐Term Viscosity of the Asthenosphere. Geophysical Research Letters 2018, 45(5), 2349-2351.
  • Al-Husseinawi Y, Li Z, Clarke P, Edwards S. Evaluation of the Stability of the Darbandikhan Dam after the 12 November 2017 Mw 7.3 Sarpol-e Zahab (Iran–Iraq Border) Earthquake. Remote Sensing 2018, 10(9), 1426.
  • Sasgen I, Martín-Español A, Horvath A, Klemann V, Petrie EJ, Wouters B, Horwath M, Pail R, Bamber JL, Clarke PJ, Konrad H, Wilson T, Drinkwater MR. Altimetry, gravimetry, GPS and viscoelastic modeling data for the joint inversion for glacial isostatic adjustment in Antarctica (ESA STSE Project REGINA). Earth System Science Data 2018, 10(1), 493-523.
  • Sasgen I, Martín-Español A, Horvath A, Klemann V, Petrie EJ, Wouters B, Horwath M, Pail R, Bamber JL, Clarke PJ, Konrad H, Drinkwater MR. Joint inversion estimate of glacial isostatic adjustment in Antarctica considering a lateral varying Earth structure (ESA STSE project REGINA). Geophysical Journal International 2017, 211(3), 1534–1553.
  • Martín-Español A, Zammit-Mangion A, Clarke PJ, Flament T, Helm V, King MA, Luthcke SB, Petrie E, Remy F, Schön N, Wouters B, Bamber JL. Spatial and temporal Antarctic ice sheet mass trends, glacio-isostatic adjustment and surface processes from a joint inversion of satellite altimeter, gravity and GPS data. Journal of Geophysical Research: Earth Surface 2016, 121(2), 182-200.
  • Webb SR, Penna NT, Clarke PJ, Webster S, Martin I, Bennitt GV. Kinematic GNSS estimation of zenith wet delay over a range of altitudes. Journal of Atmospheric and Oceanic Technology 2016, 33(1), 3-15.
  • Nield GA, Whitehouse PL, King MA, Clarke PJ. Glacial isostatic adjustment in response to changing Late Holocene behaviour of ice streams on the Siple Coast, West Antarctica. Geophysical Journal International 2016, 205(1), 1-21.
  • Amouzgar R, Liang Q, Clarke PJ, Yasuda T, Mase H. Computationally efficient tsunami modelling on Graphics Processing Units (GPUs). International Journal of Offshore and Polar Engineering 2016, 26(2), 154-160.
  • Bos MS, Penna NT, Baker TF, Clarke PJ. Ocean tide loading displacements in western Europe: 2. GPS-observed anelastic dispersion in the asthenosphere. Journal of Geophysical Research: Solid Earth 2015, 120(9), 6540–6557.
  • Penna NT, Clarke PJ, Bos MS, Baker TF. Ocean tide loading displacements in western Europe: 1. Validation of kinematic GPS estimates. Journal of Geophysical Research: Solid Earth 2015, 120(9), 6523–6539.
  • Spatar CB, Moore P, Clarke PJ. Collinearity assessment of geocentre coordinates derived from multi-satellite SLR data. Journal of Geodesy 2015, 89(12), 1197-1216.
  • Booker D, Clarke PJ, Lavallée DA. Secular changes in Earth's shape and surface mass loading derived from combinations of reprocessed global GPS networks. Journal of Geodesy 2014, 88(9), 839-855.
  • Nield GA, Barletta VR, Bordoni A, King MA, Whitehouse PL, Clarke PJ, Domack E, Scambos TA, Berthier E. Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading. Earth and Planetary Science Letters 2014, 397, 32-41.
  • Assiadi A, Edwards SJ, Clarke PJ. Enhancement of the accuracy of single-epoch GPS positioning for long baselines by local ionospheric modelling. GPS Solutions 2014, 18(3), 453-460.
  • Nield GA, Whitehouse PL, King MA, Clarke PJ, Bentley MJ. Increased ice loading in the Antarctic Peninsula since the 1850s and its effect on glacial isostatic adjustment. Geophysical Research Letters 2012, 39(17), L17504.
  • Thomas ID, King MA, Bentley MJ, Whitehouse PL, Penna NT, Williams SDP, Riva REM, Lavallee DA, Clarke PJ, King EC, Hindmarsh RCA, Koivula H. Widespread low rates of Antarctic glacial isostatic adjustment revealed by GPS observations. Geophysical Research Letters 2011, 38(22), L22302.
  • Thomas ID, King MA, Clarke PJ, Penna NT. Precipitable water vapor estimates from homogeneously reprocessed GPS data: An intertechnique comparison in Antarctica. Journal of Geophysical Research: Atmospheres 2011, 116(D4), D04107.
  • King MA, Padman L, Nicholls K, Clarke PJ, Gudmundsson H, Kulessa B, Shepherd A. Ocean tides in the Weddell Sea: new observations on the Filchner-Ronne and Larsen C ice shelves and model validation. Journal of Geophysical Research: Oceans 2011, 116(C6), C06006.
  • Ragheb AE, Edwards SJ, Clarke PJ. Using Filtered and Semicontinuous High Rate GPS for Monitoring Deformations. Journal of Surveying Engineering 2010, 136(2), 72-79.
  • Clarke PJ, Penna NT. Ocean tide loading and relative GNSS in the British Isles. Survey Review 2010, 42(317), 212-228.
  • Lavallee DA, Moore P, Clarke PJ, Petrie EJ, van Dam T, King MA. J2: An evaluation of new estimates from GPS, GRACE, and load models compared to SLR. Geophysical Research Letters 2010, 37(22), L22403.
  • Edwards SJ, Clarke PJ, Penna NT, Goebell S. An examination of network RTK GPS services in Great Britain. Survey Review 2010, 42(316), 107-121.
  • King MA, Watson CS, Penna NT, Clarke PJ. Subdaily signals in GPS observations and their effect at semiannual and annual periods. Geophysical Research Letters 2008, 35(3), L03302.
  • Ragheb AE, Clarke PJ, Edwards SJ. GPS sidereal filtering: coordinate- and carrier-phase-level strategies. Journal of Geodesy 2007, 81(5), 325-335.
  • Clarke PJ, Lavallée DA, Blewitt G, van Dam T. Basis functions for the consistent and accurate representation of surface mass loading. Geophysical Journal International 2007, 171(1), 1-10.
  • Thomas ID, King MA, Clarke PJ. A comparison of GPS, VLBI and model estimates of ocean tide loading displacements. Journal of Geodesy 2007, 81(5), 359-368.
  • Lavallée DA, van Dam T, Blewitt G, Clarke PJ. Geocenter motions from GPS: A unified observation model. Journal of Geophysical Research B: Solid Earth 2006, 111(5), -.
  • King MA, Moore P, Clarke PJ, Lavallée DA. Choice of optimal averaging radii for temporal GRACE gravity solutions, a comparison with GPS and satellite altimetry. Geophysical Journal International 2006, 166(1), 1-11.
  • King MA, Penna NT, Clarke PJ, King EC. Validation of ocean tide models around Antarctica using onshore GPS and gravity data. Journal of Geophysical Research B: Solid Earth 2005, 110(8), 1-21.
  • Clarke PJ, Lavallée DA, Blewitt G, van Dam T, Wahr J. Effect of gravitational consistency and mass conservation on seasonal surface mass loading models. Geophysical Research Letters 2005, 32(8), 1-5.
  • Mills JP, Buckley SJ, Mitchell HL, Clarke PJ, Edwards SJ. A geomatics data integration technique for coastal change monitoring. Earth Surface Processes and Landforms 2005, 30(6), 651-664.
  • Allinson CR, Clarke PJ, Edwards SJ, King MA, Baker TF, Cruddace PR. Stability of direct GPS estimates of ocean tide loading. Geophysical Research Letters 2004, 31(15), L15603.
  • Gross R, Blewitt G, Clarke PJ, Lavallée DA. Degree-2 harmonics of the Earth's mass load estimated from GPS and Earth rotation data. Geophysical Research Letters 2004, 31(7), L07601-4.
  • Blewitt G, Clarke PJ. Inversion of Earth's changing shape to weigh sea level in static equilibrium with surface mass redistribution. Journal of Geophysical Research: Solid Earth 2003, 108(B6), 2311.
  • Hunstad I, Selvaggi G, D'Agostino N, England P, Clarke PJ, Pierozzi M. Geodetic strain in peninsular Italy between 1875 and 2001. Geophysical Research Letters 2003, 30(4), 1181.
  • Rainbow JJ, Clarke PJ. Optimising navigational precision from potential GNSS constellations. Hydrographic Journal 2002, (103), 3-9.
  • Wadge G, Webley PW, James IN, Bingley R, Dodson A, Waugh S, Veneboer T, Puglisi G, Mattia M, Baker D, Edwards SC, Edwards SJ, Clarke PJ. Atmospheric models, GPS and InSAR measurements of the tropospheric water vapour field over Mount Etna. Geophysical Research Letters 2002, 29(19), 1905.
  • Blewitt G, Lavallée DA, Clarke PJ, Nurutdinov K. A new global mode of Earth deformation: Seasonal cycle detected. Science 2001, 294(5550), 2342-2345.
  • Wright TJ, Parsons BE, Jackson JA, Haynes M, Fielding EJ, England PC, Clarke PJ. Source parameters of the 1 October 1995 Dinar (Turkey) earthquake from SAR interferometry and seismic bodywave modelling. Earth and Planetary Science Letters 1999, 172(1-2), 23-37.
  • Clarke PJ, Davies RR, England PC, Parsons B, Billiris H, Paradissis D, Veis G, Cross PA, Denys PH, Ashkenazi V, Bingley R, Kahle HG, Muller MV, Briole P. Crustal strain in central Greece from repeated GPS measurements in the interval 1989-1997. Geophysical Journal International 1998, 135(1), 195-214.
  • Clarke PJ, Paradissis D, Briole P, England PC, Parsons BE, Billiris H, Veis G, Ruegg J-C. Geodetic investigation of the 13 May 1995 Kozani-Grevena (Greece) earthquake. Geophysical Research Letters 1997, 24(6), 707-710.
  • Clarke PJ, Davies RR, England PC, Parsons BE, Billiris H, Paradissis D, Veis G, Denys PH, Cross PA, Ashkenazi V, Bingley R. Geodetic estimate of seismic hazard in the Gulf of Korinthos. Geophysical Research Letters 1997, 24(11), 1303-1306.

• Conference Proceedings (inc. Abstract)

  • Ragheb AE, Clarke PJ, Edwards SJ. Coordinate-space and observation-space filtering methods for sidereally repeating errors in GPS: Performance and filter lifetime. In: Proceedings of the Institute of Navigation, National Technical Meeting. 2007, San Diego, California: Curran Associates, Inc.

• Research Dataset/Database

  • Webb SR, Penna NT, Clarke PJ. Snowdon Mountain Railway Global Navigation Satellite Systems (GNSS): Repeatable Kinematic Dataset Collection from Snowdonia. 2015. Harwell: Centre for Environmental Data Archival.