The Surface Water and Ocean Topography (SWOT) mission will provide for the first time from space two-dimensional high-resolution maps of surface water levels globally over ocean and inland waters. If SWOT meets its performance targets, it will represent a major milestone in our ability to observe, study and understand the nature and evolution of the Earth’s marine and land surface water systems, globally.

The UK Space Agency invested in SWOT jointly with the US NASA, French CNES and Canadian Space Agency to enable the implementation and launch of this mission. The SWOT-UK project proposes a comprehensive programme of campaigns and multidisciplinary research centred on the Bristol Channel and River Severn region as the UK contribution to the international SWOT Science Team validation efforts. In accordance with the requirements of the NERC/UKSA SWOT CalVal call, SWOT-UK takes an open and inclusive approach, putting special emphasis on disseminating value-added SWOT validation datasets and engaging with the wider UK science and stakeholder communities to raise awareness of the SWOT capabilities.

PI: Dr Christine Gommenginger, National Oceanography Centre
Email: Christine.Gommenginger at noc.ac.uk

Dates
–
Funding

NERC and UK Space Agency SWOT CalVal AO

Aim

The objectives of SWOT-UK are:

  • To assemble a large dataset of quality-controlled ground-truth and satellite data of water level, slope and river discharge over the Bristol Channel/River Severn region.
  • To carry out a targeted campaign of airborne and shipborne surveys during the SWOT 90-days daily repeat cal-val mission phase to complement existing observations.
  • To investigate critical aspects of SWOT instrument and mission performance using pre-launch and campaign data to determine the quality of SWOT data in coastal and estuarine settings.
  • To use SWOT data for novel validation of 2D ocean, wave and hydrodynamic models, and their ability to resolve marine-fluvial interactions and water level spatial variability.
  • To represent the UK within the international SWOT Science Team, interact with SWOT and the UKSA, and engage with key flood forecasting and coastal management stakeholders and the wider UK community to disseminate findings and quality-controlled datasets.

Articles

Bell, P. S., 2022. Mapping Earth’s Water Bodies. International Water Power and Dam Construction, November 2022, available online at: https://content.yudu.com/web/442ay/0A444q7/WPD1122-Pros/html/index.html?page=26&origin=reader

Lichtman, I. D., 2023. Swot in an Estuary-River system. AVISO Image of the Month - May 2023, [blog] available online at: https://www.aviso.altimetry.fr/en/news/idm/2023/may-2023-swot-in-an-estuary-river-system.html

Lichtman, I. D., Bell, P. S., Gommenginger, C., Banks, C., Calafat, F. M., Brown, J., & Williams, S. D. P. (2025). Evaluating water levels from the surface water and ocean topography (SWOT) mission in a hyper‐tidal coastal and estuarine environment. Earth and Space Science, 12, e2024EA004104. https://doi.org/10.1029/2024EA004104

Datasets

Lichtman, I.D., Bell, P. S., Williams, S. D. P., Gommenginger, C., Banks, C., Calafat, F. M. & Brown, J., 2024. Water level data from the Bristol Channel and Severn Estuary and River region for validation of satellite altimeters, 2012-2023 (SWOT-UK project). [Dataset] NERC EDS British Oceanographic Data Centre NOC, doi: 10.5285/25129f9a-7369-9ab2-e063-7086abc05905, 
https://www.bodc.ac.uk/data/published_data_library/catalogue/10.5285/25129f9a-7369-9ab2-e063-7086abc05905

Presentations

Bell, P. S., 2024. Satellite remote sensing of estuaries. Estuaries & Coasts of North-west England, ECSA Focus meeting 2024, 20-22 May 2024, Carlisle, UK [Presentation].

Bell, P. S., Neil, C., Lichtman, D., and Sams, C., 2025. SWOT-Satellite-Enabled Tidal Data in Estuaries. UK Coastal Research Conference, Liverpool, UK, 1-3 July 2025 [Presentation].

Gommenginger, C., Lichtman, I., Banks, C., Calafat, F. and Bell, P., 2024. Observing Water Levels in Coastal, Estuarine, and Riverine Environments with In-Situ Gauges, Nadir Altimetry and Swath Altimetry: Challenges and Opportunities. 30 Years of Progress in Radar Altimetry Symposium, Montpellier, France, 2-7 September 2024 [Presentation] available online at: https://www.dropbox.com/scl/fi/ocf7ivuqdgsdpkfpcikup/01-03-Gommenginger.pdf?rlkey=npnf1wch49zhwia3ahv50nd1o&e=2&dl=0

Lichtman, I. D., Shaw, A., Banks, C., Calafat, F. J. M., Gommenginger, C. and Bell, P., 2023. Towards validation of SWOT and new coastal processing algorithms: An altimetry and water level gauge case study in the Bristol Channel and Severn Estuary area. 13th Coastal Altimetry Workshop and Coastal Altimetry Training, Cadiz, Spain, 6-10 February 2023 [Presentation].

Lichtman, I. D., Shaw, A., Banks, C., Calafat, F. J. M., Gommenginger, C. and Bell, P., 2023. Towards validation of SWOT and new coastal altimetry algorithms: An altimetry and water level gauge case study in the Bristol Channel and Severn Estuary. UK Coastal Research Conference 2023, Plymouth, UK, 4-6 July [Presentation].

Lichtman, D., Banks, C., Calafat, F., Gommenginger, C. and Bell, P., 2023. Towards validation of SWOT in the coastal zone: a radar altimetry and water level gauge case study in the Bristol Channel and Severn River-Estuary system. Ocean Surface Topography Science Team Meeting, 7-11 November 2023, San Juan, Puerto Rico [Poster] available online at: https://ostst.aviso.altimetry.fr/?id=95&no_cache=1&tx_ausyclsseminar_pi2%5bobjAbstracte%5d=3809

Lichtman, D., Banks, C., Calafat, F., Martin, A., Gommenginger, C. and Bell, P., 2024. Evaluating SWOT in the Coastal Zone: Comparisons with Radar Altimetry and Water Level Gauge Data in the Bristol Channel and Severn River-Estuary System, UK. AGU Ocean Sciences Meeting, 18-24 Feburary 2024, New Orleans, USA [Poster] https://www.researchgate.net/publication/378877397_Evaluating_SWOT_in_the_Coastal_Zone_Comparisons_with_Radar_Altimetry_and_Water_Level_Gauge_Data_in_the_Bristol_Channel_and_Severn_River-Estuary_System_UK

Lichtman, D. I., Banks, C., Calafat, F., Gommenginger, C. and Bell, P., 2024. Validating SWOT in the coastal zone: a radar altimetry and tide gauge case study in the Bristol Channel and Severn River-Estuary system. EGU General Assembly, 14–19 April 2024, Vienna, Austria. [Presentation] available online at: https://www.researchgate.net/publication/380005827_Validating_SWOT_in_the_coastal_zone_a_radar_altimetry_and_tide_gauge_case_study_in_the_Bristol_Channel_and_Severn_River-Estuary_system

Lichtman, D. I., Bell, P., Cotton, P. D., Banks, C., Calafat, F. and Gommenginger, C., 2024. The Surface Water and Ocean Topography Mission in the Coastal Zone: 2D Altimetry for Mapping Intertidal Morphology Area and Change. 43rd EARSeL Symposium, 17-20 June 2024, Manchester, UK. [Presentation]

Lichtman, I. D., Bell, P. S., Banks, C., Gommenginger, C., Brown, J. & Valiente, N. G., 2025. Can wave processes be seen in SWOT HR data? – A first look. 6th meeting of the Challenger Society Special Interest Group on Wind Waves, Liverpool, UK, 30 June 2025 [Poster], https://projects.noc.ac.uk/windwavesSIG/sites/windwaves/files/documents/S3_Lichtman.pdf