Overview

Helen is a part-time lecturer in mathematics at Exeter University and a senior scientist at the Met Office, with research interests in modelling the transport and dispersion of atmospheric substances. Her specific interests lie in the development of the Met Office's atmospheric dispersion model NAME (Numerical Atmospheric-dispersion Modelling Environment) and in using NAME in a wide range of applications, including chemical, biological and radiological releases, volcanic clouds, smoke plumes, air quality and disease spread. She is also interested in inversion techniques which combine observations and modelling to estimate uncertain emission source terms.

Helen has a mathematics degree and a PGCE in secondary mathematics from Oxford University, and a PhD in integrable nonlinear differential equations from the University of Kent at Canterbury.

Personal Met Office webpage

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Publications

_{Copyright Notice: Any articles made available for download are for personal use only. Any other use requires prior permission of the author and the copyright holder.}

| 2024 | 2023 | 2022 | 2021 | 2020 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2008 | 2007 | 2006 | 2005 | 2002 | 2001 | 2000 |

2024

• Johnson C, Millward F, Webster H. (2024) An operational model for wind-blown volcanic umbrella clouds, DOI:10.5194/egusphere-egu24-9933. [PDF]
• Webster H, Thomson D, Salter J. (2024) A Bayesian inversion method for estimating ash emissions: accounting for meteorological uncertainty & quantifying uncertainty in the estimated emissions, DOI:10.5194/egusphere-egu24-9544. [PDF]

2023

• Salter JM, Webster HN, Saint C. (2023) Technical note: Exploring parameter and meteorological uncertainty via emulation in volcanic ash atmospheric dispersion modelling, DOI:10.5194/egusphere-2023-2870. [PDF]
• Millward FJ, Webster HN, Johnson CG. (2023) Modeling Wind‐Blown Umbrella Clouds in Lagrangian Dispersion Models, Journal of Geophysical Research: Atmospheres, volume 128, no. 17, DOI:10.1029/2023jd039115. [PDF]
• Selvaratnam V, Thomson DJ, Webster HN. (2023) Validation of the Atmospheric Dispersion Model NAME against Long-Range Tracer Release Experiments, Journal of Applied Meteorology and Climatology, volume 62, no. 9, pages 1165-1174, DOI:10.1175/jamc-d-23-0021.1.

2022

• Webster HN, Thomson DJ. (2022) Using Ensemble Meteorological Data Sets to Treat Meteorological Uncertainties in a Bayesian Volcanic Ash Inverse Modeling System: A Case Study, Grímsvötn 2011, Journal of Geophysical Research: Atmospheres, volume 127, no. 24, DOI:10.1029/2022jd036469. [PDF]
• Cowan N, Nemitz E, Walker JT, Fowler D, Finnigan JJ, Webster HN, Levy P, Twigg M, Tang SY, Bachiller-Jareno N. (2022) Review of methods for assessing deposition of reactive nitrogen pollutants across complex terrain with focus on the UK, Environmental Science Atmospheres, volume 2, no. 5, pages 829-851, DOI:10.1039/d2ea00012a.
• Harvey NJ, Dacre HF, Saint C, Prata AT, Webster HN, Grainger RG. (2022) Quantifying the impact of meteorological uncertainty on emission estimates and the risk to aviation using source inversion for the Raikoke 2019 eruption, Atmospheric Chemistry and Physics, volume 22, no. 13, pages 8529-8545, DOI:10.5194/acp-22-8529-2022. [PDF]
• Harvey NJ, Dacre HF, Saint C, Prata A, Webster HN, Grainger RG. (2022) Quantifying the impact of meteorological uncertainty on emission estimates and volcanic ash forecasts of the Raikoke 2019 eruption, DOI:10.5194/acp-2021-973. [PDF]

2021

• Pelley RE, Thomson DJ, Webster HN, Cooke MC, Manning AJ, Witham CS, Hort MC. (2021) A near-real-time method for estimating volcanic ash emissions using satellite retrievals, Atmosphere, volume 12, no. 12, DOI:10.3390/atmos12121573.

2020

• Selvaratnam V, Webster H, Thomson D, Devenish B. (2020) The impact of high time resolution meteorology on dispersion models, 20th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, HARMO 2020.
• Harvey NJ, Dacre HF, Webster HN, Taylor IA, Khanal S, Grainger RG, Cooke MC. (2020) The Impact of Ensemble Meteorology on Inverse Modeling Estimates of Volcano Emissions and Ash Dispersion Forecasts: Grímsvötn 2011, Atmosphere, volume 11, no. 10, pages 1022-1022, DOI:10.3390/atmos11101022. [PDF]
• Beckett FM, Witham CS, Leadbetter SJ, Crocker R, Webster HN, Hort MC, Jones AR, Devenish BJ, Thomson DJ. (2020) Atmospheric Dispersion Modelling at the London VAAC: A Review of Developments since the 2010 Eyjafjallajökull Volcano Ash Cloud, Atmosphere, volume 11, no. 4, pages 352-352, DOI:10.3390/atmos11040352. [PDF]
• Beckett F, Witham C, Leadbetter S, Crocker R, Webster H, Hort M, Jones A, Devenish B, Thomson D. (2020) Dispersion Modelling at the London VAAC 10 Years after the Eyjafjallajökull Ash Cloud, DOI:10.5194/egusphere-egu2020-4774. [PDF]
• Harvey N, Dacre H, Webster H. (2020) The impact of ensemble meteorology on volcano emission estimates and ash dispersion forecasts, DOI:10.5194/egusphere-egu2020-19130. [PDF]
• Dacre HF, Bedwell P, Hertwig D, Leadbetter SJ, Loizou P, Webster HN. (2020) Improved representation of particle size and solubility in model simulations of atmospheric dispersion and wet-deposition from Fukushima, Journal of Environmental Radioactivity, volume 217, DOI:10.1016/j.jenvrad.2020.106193.
• Webster HN, Devenish BJ, Mastin LG, Thomson DJ, Van Eaton AR. (2020) Operational Modelling of Umbrella Cloud Growth in a Lagrangian Volcanic Ash Transport and Dispersion Model, Atmosphere, volume 11, no. 2, pages 200-200, DOI:10.3390/atmos11020200. [PDF]

2018

• Arnold T, Manning A, Kim J, Li S, Webster H, Thomson D, Mühle J, Weiss RF, Park S, O'Doherty S. (2018) Inverse modelling of CF<sub>4</sub> and NF<sub>3</sub> emissions in East Asia, DOI:10.5194/acp-2017-1171. [PDF]
• Arnold T, Manning A, Kim J, Li S, Webster H, Thomson D, Mühle J, Weiss RF, Park S, O'Doherty S. (2018) Supplementary material to "Inverse modelling of CF<sub>4</sub> and NF<sub>3</sub> emissions in East Asia", DOI:10.5194/acp-2017-1171-supplement. [PDF]
• Harvey NJ, Huntley N, Dacre HF, Goldstein M, Thomson D, Webster H. (2018) Multi-level emulation of a volcanic ash transport and dispersion model to quantify sensitivity to uncertain parameters, NATURAL HAZARDS AND EARTH SYSTEM SCIENCES, volume 18, no. 1, pages 41-63, DOI:10.5194/nhess-18-41-2018. [PDF]
• Webster HN, Whitehead T, Thomson DJ. (2018) Parameterizing Unresolved Mesoscale Motions in Atmospheric Dispersion Models, JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY, volume 57, no. 3, pages 645-657, DOI:10.1175/JAMC-D-17-0075.1. [PDF]
• Arnold T, Manning AJ, Kim J, Li S, Webster H, Thomson D, Mühle J, Weiss RF, Park S, O'Doherty S. (2018) Inverse modelling of CF4 and NF3 emissions in East Asia, Atmospheric Chemistry and Physics, volume 18, no. 18, pages 13305-13320, DOI:10.5194/acp-18-13305-2018.

2017

• Webster HN, Thomson DJ. (2017) A particle size dependent wet deposition scheme for the lagrangian dispersion model, name, HARMO 2017 - 18th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings, volume 2017-October, pages 431-435.

2016

• Selvaratnam V, Thomson D, Webster H. (2016) Validation of the atmospheric dispersion model name against long-range tracer release experiments, HARMO 2016 - 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings, volume 2016-May, pages 56-60.
• Webster HN, Thomson DJ, Cooke MC, Pelley RE. (2016) Improvements to an operational inversion method for estimating volcanic ash source parameters using satellite retrievals, HARMO 2016 - 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings, volume 2016-May, pages 518-522.
• Harvey NJ, Huntley N, Dacre H, Goldstein M, Thomson D, Webster H. (2016) Multi-level emulation of a volcanic ash transport and dispersion model to quantify sensitivity to uncertain parameters, DOI:10.5194/nhess-2016-288. [PDF]
• Wilkins KL, Watson IM, Kristiansen NI, Webster HN, Thomson DJ, Dacre HF, Prata AJ. (2016) Using data insertion with the NAME model to simulate the 8 May 2010 Eyjafjallajokull volcanic ash cloud, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, volume 121, no. 1, pages 306-323, DOI:10.1002/2015JD023895. [PDF]

2015

• Dacre HF, Grant ALM, Harvey NJ, Thomson DJ, Webster HN, Marenco F. (2015) Volcanic ash layer depth: Processes and mechanisms, GEOPHYSICAL RESEARCH LETTERS, volume 42, no. 2, pages 637-645, DOI:10.1002/2014GL062454. [PDF]

2014

• Webster H, Whitehead T, Thomson D. (2014) Parametrizing low-frequency mesoscale motions in atmospheric dispersion models, HARMO 2014 - 16th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings, pages 312-317.
• Leadbetter S, Hort M, Jones A, Webster H, Witham C. (2014) Modelling the regional deposition of radionuclides from the fUKushima DAI-ICHI nuclear power plant with name, HARMO 2014 - 16th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, Proceedings, pages 621-626.
• Wilkins KL, Mackie S, Watson IM, Webster HN, Thomson DJ, Dacre HF. (2014) Data insertion in volcanic ash cloud forecasting, ANNALS OF GEOPHYSICS, volume 57. [PDF]

2013

• Webster HN, Thomson DJ, Jones AR. (2013) H15-25: Modelling wet deposition with high resolution precipitation data, Proceedings of the 15th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, HARMO 2013, pages 378-381.

2012

• Mohan R, Walton HA, Thomson D, Webster H, Wilkinson P, Grundy C, Murray V, Leonardi G. (2012) The Buncefield Oil Depot Fire of 2005: Potential Air-Pollution Health Impacts Under Alternative Meteorological Scenarios, PLoS Currents, DOI:10.1371/currents.RRN1300.
• Kristiansen NI, Stohl A, Prata AJ, Bukowiecki N, Dacre H, Eckhardt S, Henne S, Hort MC, Johnson BT, Marenco F. (2012) Performance assessment of a volcanic ash transport model mini-ensemble used for inverse modeling of the 2010 Eyjafjallajokull eruption, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, volume 117, article no. ARTN D00U11, DOI:10.1029/2011JD016844. [PDF]
• Millington SC, Saunders RW, Francis PN, Webster HN. (2012) Simulated volcanic ash imagery: A method to compare NAME ash concentration forecasts with SEVIRI imagery for the Eyjafjallajokull eruption in 2010, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, volume 117, article no. ARTN D00U17, DOI:10.1029/2011JD016770. [PDF]
• Johnson B, Turnbull K, Brown P, Burgess R, Dorsey J, Baran AJ, Webster H, Haywood J, Cotton R, Ulanowski Z. (2012) In situ observations of volcanic ash clouds from the FAAM aircraft during the eruption of Eyjafjallajokull in 2010, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, volume 117, article no. ARTN D00U24, DOI:10.1029/2011JD016760. [PDF]
• Witham C, Webster H, Hort M, Jones A, Thomson D. (2012) Modelling concentrations of volcanic ash encountered by aircraft in past eruptions, ATMOSPHERIC ENVIRONMENT, volume 48, pages 219-229, DOI:10.1016/j.atmosenv.2011.06.073. [PDF]
• Webster HN, Thomson DJ, Johnson BT, Heard IPC, Turnbull K, Marenco F, Kristiansen NI, Dorsey J, Minikin A, Weinzierl B. (2012) Operational prediction of ash concentrations in the distal volcanic cloud from the 2010 Eyjafjallajokull eruption, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, volume 117, article no. ARTN D00U08, DOI:10.1029/2011JD016790. [PDF]

2011

• Webster HN, Thomson DJ. (2011) Dry deposition modelling in a Lagrangian dispersion model, International Journal of Environment and Pollution, volume 47, no. 1/2/3/4, pages 1-1, DOI:10.1504/ijep.2011.047322. [PDF]
• Polson D, Fowler D, Nemitz E, Skiba U, McDonald A, Famulari D, Di Marco C, Simmons I, Weston K, Purvis R. (2011) Estimation of spatial apportionment of greenhouse gas emissions for the UK using boundary layer measurements and inverse modelling technique, ATMOSPHERIC ENVIRONMENT, volume 45, no. 4, pages 1042-1049, DOI:10.1016/j.atmosenv.2010.10.011. [PDF]
• Webster HN, Thomson DJ. (2011) Dry deposition modelling in a Lagrangian dispersion model, INTERNATIONAL JOURNAL OF ENVIRONMENT AND POLLUTION, volume 47, no. 1-4, pages 1-9. [PDF]
• Webster HN, Thomson DJ, Johnson BT, Heard IPC, Turnbull K, Marenco F, Kristiansen NI, Dorsey J, Minikin A, Weinzierl B. (2011) A comparison of namemodel predictions and observations from the 2010 Eyjafjallajökull eruption, HARMO 2011 - Proceedings of the 14th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, pages 699-703.
• Marenco F, Johnson B, Turnbull K, Newman S, Haywood J, Webster H, Ricketts H. (2011) Airborne lidar observations of the 2010 Eyjafjallajokull volcanic ash plume, JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, volume 116, article no. ARTN D00U05, DOI:10.1029/2011JD016396. [PDF]
• Webster HN, Devenish BJ, Haywood JM, Lock AP, Thomson DJ. (2011) Using plume rise schemes to model highly buoyant plumes from large fires, INTERNATIONAL JOURNAL OF ENVIRONMENT AND POLLUTION, volume 44, no. 1-4, pages 226-234, DOI:10.1504/IJEP.2011.038422. [PDF]

2010

• Devenish BJ, Rooney GG, Webster HN, Thomson DJ. (2010) The Entrainment Rate for Buoyant Plumes in a Crossflow, BOUNDARY-LAYER METEOROLOGY, volume 134, no. 3, pages 411-439, DOI:10.1007/s10546-009-9464-5. [PDF]
• Wallensten A, Moore P, Webster H, Johnson C, van der Burgt G, Pritchard G, Ellis-Iversen J, Oliver I. (2010) Q fever outbreak in Cheltenham, United Kingdom, in 2007 and the use of dispersion modelling to investigate the possibility of airborne spread, EUROSURVEILLANCE, volume 15, no. 12, pages 16-22, article no. ARTN 19521. [PDF]

2008

• Webster HN, Thomson DJ. (2008) Dry deposition modelling in a Lagrangian dispersion model, Hrvatski Meteoroloski Casopis, volume 43 PART 1, pages 287-291.

2007

• Webster HN, Carroll EB, Jones AR, Manning AJ, Thomson DJ. (2007) The Buncefield oil depot incident: a discussion of the meteorology, Weather, volume 62, no. 12, pages 325-330, DOI:10.1002/wea.164. [PDF]
• Gloster J, Mellor PS, Manning AJ, Webster HN, Hort MC. (2007) Assessing the risk of windborne spread of bluetongue in the 2006 outbreak of disease in northern Europe, VETERINARY RECORD, volume 160, no. 2, pages 54-56, DOI:10.1136/vr.160.2.54. [PDF]
• Webster HN, Beare RJ, Devenish BJ, Haywood JM, Lock AP, Thomson DJ. (2007) Using plume rise schemes to model highly buoyant plumes from large fires, Proceedings of the 11th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, HARMO 2007, pages 220-224.
• Webster H, Beare R, Devenish B, Haywood J, Lock A, Thomson D. (2007) Using plume rise schemes to model highly buoyant plumes from large fires, Proceedings of the 11th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes, HARMO 2007.

2006

• Gloster J, Sellers R, Webster H, Valarcher J. (2006) Assessing the risk of airborne spread of foot‐and‐mouth disease: A case study, Weather, volume 61, no. 5, pages 137-142, DOI:10.1256/wea.164.05. [PDF]

2005

• Morrison NL, Webster HN. (2005) An Assessment of Turbulence Profiles in Rural and Urban Environments Using Local Measurements and Numerical Weather Prediction Results, Boundary-Layer Meteorology, volume 115, no. 2, pages 223-239, DOI:10.1007/s10546-004-4422-8. [PDF]

2002

• Webster HN, Thomson DJ. (2002) Validation of a Lagrangian model plume rise scheme using the Kincaid data set, Atmospheric Environment, volume 36, no. 32, pages 5031-5042, DOI:10.1016/s1352-2310(02)00559-9. [PDF]

2001

• Mansfield EL, Webster HN. (2001) On One‐Parameter Families of Painlevé III, Studies in Applied Mathematics, volume 101, no. 3, pages 321-341, DOI:10.1111/1467-9590.00096. [PDF]

2000

• Кларксон ПА, Clarkson PA, Менсфилд ЭЛ, Mansfield EL, Вебстер ХН, Webster HN. (2000) О соотношении между дискретными и непрерывными уравнениями Пенлеве, Theoretical and Mathematical Physics, volume 122, no. 1, pages 5-22, DOI:10.4213/tmf551.
• Clarkson PA, Mansfield EL, Webster HN. (2000) On the relation between the continuous and discrete Painlevé equations, Theoretical and Mathematical Physics, volume 122, no. 1, pages 1-16, DOI:10.1007/bf02551165. [PDF]
• Clarkson PA, Webster HN. (2000) Hierarchies of exact solutions for the discrete third Painlevé equation, Chaos, Solitons & Fractals, volume 11, no. 1-3, pages 53-71, DOI:10.1016/s0960-0779(98)00268-9. [PDF]

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