Amos Lawless
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+44 (0) 118 378 5018
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Professor
Professor of Data Assimilation
Office
Room 102Building location
MathematicsAreas of interest
- Optimization techniques for data assimilation
- Data assimilation for Hamiltonian systems
- Imposing balance in variational data assimilation
- Data assimilation for multi-scale systems
- Data assimilation for morphodynamic prediction
Research centres and groups
Websites/blogs
Publications
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Shataer, S.
,
Lawless, A.
,
Nichols, N.
ORCID: 0000-0003-1133-5220
(2023)
Conditioning of hybrid variational data assimilation.
Numerical Linear Algebra with Applications
ISSN:
1099-1506
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Francis, D.
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Fowler, A.
ORCID: 0000-0003-3650-3948
,
Lawless, A.
,
Eyre, J.
,
Migliorini, S.
(2023)
The effective use of anchor observations in variational bias correction in the presence of model bias.
Quarterly Journal of the Royal Meteorological Society
ISSN:
1477-870X
|
doi:
https://dx.doi.org/10.1002/qj.4482
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Leung, T.
ORCID: 0000-0003-0056-284X
,
Lawless, A.
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Nichols, N.
ORCID: 0000-0003-1133-5220
,
Lea, D.
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Martin, M.
(2022)
The impact of hybrid oceanic data assimilation in a coupled model: a case study of a tropical cyclone.
Quarterly Journal of the Royal Meteorological Society
, 148
(746).
pp.
2410-2430.
ISSN:
0035-9009
|
doi:
https://dx.doi.org/10.1002/qj.4309
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Tabeart, J.
,
Dance, S.
ORCID: 0000-0003-1690-3338
,
Lawless, A.
,
Nichols, N.
ORCID: 0000-0003-1133-5220
,
Waller, J.
(2022)
New bounds on the condition number of the Hessian of
the preconditioned variational data assimilation problem.
Numerical Linear Algebra with Applications
, 29
(1).
ISSN:
1099-1506
|
doi:
https://dx.doi.org/10.1002/nla.2405
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Daužickaitė, I.
ORCID: 0000-0002-1285-1764
,
Lawless, A.
,
Scott, J.
ORCID: 0000-0003-2130-1091
,
Van Leeuwen, P.
ORCID: 0000-0003-2325-5340
(2021)
Randomised preconditioning for the forcing formulation of weak constraint 4D‐Var.
Quarterly Journal of the Royal Meteorological Society
, 147
(740).
pp.
3719-3734.
ISSN:
1477-870X
|
doi:
https://dx.doi.org/10.1002/qj.4151
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Dauzickaite, I.
,
Lawless, A.
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Scott, J.
ORCID: 0000-0003-2130-1091
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Leeuwen, P.
(2021)
On time-parallel preconditioning for the state formulation of incremental weak constraint 4D-Var.
Quarterly Journal of the Royal Meteorological Society
, 147
(740).
pp.
3521-3529.
ISSN:
1477-870X
|
doi:
https://dx.doi.org/10.1002/qj.4140
- Otkin, J. , Potthast, R. , Lawless, A. (2021) Nonlinear conditional model bias estimation for data assimilation. SIAM Journal on Applied Dynamical Systems , 20 (1). pp. 299-332. ISSN: 1536-0040 | doi: https://dx.doi.org/10.1137/19M1294848
- Dauzickaite, I. , Lawless, A. , Scott, J. , Van Leeuwen, P. (2020) Spectral estimates for saddle point matrices arising in weak constraint four-dimensional variational data assimilation. Numerical Linear Algebra with Applications , 27 (5). ISSN: 1099-1506 | doi: https://dx.doi.org/10.1002/nla.2313
- Smith, P. , Lawless, A. , Nichols, N. (2020) The role of cross-domain error correlations in strongly coupled 4D-Var atmosphere-ocean data assimilation. Quarterly Journal of the Royal Meteorological Society , 146 (730). pp. 2450-2465. ISSN: 1477-870X | doi: https://dx.doi.org/10.1002/qj.3802
- Owens, M. , Lang, M. , Riley, P. , Lockwood, M. , Lawless, A. (2020) Quantifying the latitudinal representivity of in situ solar wind observations. Journal of Space Weather and Space Climate , 10 ISSN: 2115-7251 | doi: https://dx.doi.org/10.1051/swsc/2020009
- Tabeart, J. , Dance, S. , Lawless, A. , Migliorini, S. , Nichols, N. , Smith, F. , Waller, J. (2020) The impact of using reconditioned correlated observation error covariance matrices in the Met office 1D-Var system. Quarterly Journal of the Royal Meteorological Society , 146 (728). pp. 1372-1390. ISSN: 1477-870X | doi: https://dx.doi.org/10.1002/qj.3741
- Pinnington, E. , Quaife, T. , Lawless, A. , Williams, K. , Arkebauer, T. , Scoby, D. (2020) The land variational ensemble data assimilation framework: LaVEnDAR v1.0.0. Geoscientific Model Development , 13 pp. 55-69. ISSN: 1991-9603 | doi: https://dx.doi.org/10.5194/gmd-13-55-2020
- Tabeart, J. , Dance, S. , Lawless, A. , Nichols, N. , Waller, J. (2020) Improving the condition number of estimated covariance matrices. Tellus A: Dynamic Meteorology & Oceanography , 72 (1). pp. 1-19. ISSN: 1600-0870 | doi: https://dx.doi.org/10.1080/16000870.2019.1696646
- Sgura, I. , Lawless, A. , Bozzini, B. (2019) Parameter estimation for a morphochemical reaction-diffusion model of electrochemical pattern formation. Inverse Problems in Science and Engineering , 27 (5). pp. 618-647. ISSN: 1741-5985 | doi: https://dx.doi.org/10.1080/17415977.2018.1490278
- Tabeart, J. , Dance, S. , Haben, S. , Lawless, A. , Nichols, N. , Waller, J. (2018) The conditioning of least squares problems in variational data assimilation. Numerical Linear Algebra with Applications , 25 (5). ISSN: 1099-1506 | doi: https://dx.doi.org/10.1002/nla.2165
- Smith, P. , Lawless, A. , Nichols, N. (2018) Treating sample covariances for use in strongly coupled atmosphere-ocean data assimilation. Geophysical Research Letters , 45 (1). pp. 445-454. ISSN: 0094-8276 | doi: https://dx.doi.org/10.1002/2017gl075534
- Otkin, J. , Potthast, R. , Lawless, A. (2018) Nonlinear bias correction for satellite data assimilation using Taylor series polynomials. Monthly Weather Review , 146 (1). pp. 263-285. ISSN: 0027-0644 | doi: https://dx.doi.org/10.1175/mwr-d-17-0171.1
- Smith, P. , Lawless, A. , Nichols, N. (2017) Estimating forecast error covariances for strongly coupled atmosphere-ocean 4D-Var data assimilation. Monthly Weather Review , 145 (10). pp. 4011-4035. ISSN: 0027-0644 | doi: https://dx.doi.org/10.1175/MWR-D-16-0284.1
- Pinnington, E. , Casella, E. , Dance, S. , Lawless, A. , Morison, J. , Nichols, N. , Wilkinson, M. , Quaife, T. (2017) Understanding the effect of disturbance from selective felling on the carbon dynamics of a managed woodland by combining observations with model predictions. JGR-Biogeosciences , 122 (4). pp. 886-902. ISSN: 2169-8961 | doi: https://dx.doi.org/10.1002/2017JG003760
- Howes, K. , Fowler, A. , Lawless, A. (2017) Accounting for model error in strong-constraint 4DVar data assimilation. Quarterly Journal of the Royal Meteorological Society , 143 (704). pp. 1227-1240. ISSN: 1477-870X | doi: https://dx.doi.org/10.1002/qj.2996
- Pinnington, E. , Casella, E. , Dance, S. , Lawless, A. , Morison, J. , Nichols, N. , Wilkinson, M. , Quaife, T. (2016) Investigating the role of prior and observation error correlations in improving a model forecast of forest carbon balance using Four Dimensional Variational data assimilation. Agricultural and Forest Meteorology , 228-229 pp. 299-314. ISSN: 0168-1923 | doi: https://dx.doi.org/10.1016/j.agrformet.2016.07.006
- Fowler, A. and Lawless, A. (2016) An idealized study of coupled atmosphere-ocean 4D-Var in the presence of model error. Monthly Weather Review , 144 (10). pp. 4007-4030. ISSN: 0027-0644 | doi: https://dx.doi.org/10.1175/MWR-D-15-0420.1
- Smith, P. , Fowler, A. , Lawless, A. (2015) Exploring strategies for coupled 4D-Var data assimilation using an idealised atmosphere-ocean model. Tellus A , 67 ISSN: 1600-0870 | doi: https://dx.doi.org/10.3402/tellusa.v67.27025
- Haben, S. , Lawless, A. , Nichols, N. (2014) Conditioning and preconditioning of the optimal state estimation problem. Dept of Mathematics & Statistics, University of Reading (2014-08). pp 21.
- Waller, J. , Dance, S. , Lawless, A. , Nichols, N. (2014) Estimating correlated observation error statistics using an ensemble transform Kalman filter. Tellus A , 66 ISSN: 1600-0870 | doi: https://dx.doi.org/10.3402/tellusa.v66.23294
- Waller, J. , Dance, S. , Lawless, A. , Nichols, N. , Eyre, J. (2014) Representativity error for temperature and humidity using the Met Office high-resolution model. Quarterly Journal of the Royal Meteorological Society , 140 (681). pp. 1189-1197. ISSN: 1477-870X | doi: https://dx.doi.org/10.1002/qj.2207
- Lawless, A. (2013) Variational data assimilation for very large environmental problems. In: Cullen, M. , Freitag, M. , Kindermann, S. , Scheichl, R. , (eds.) Large Scale Inverse Problems: Computational Methods and Applications in the Earth Sciences. Radon Series on Computational and Applied Mathematics , 2. De Gruyter (13). , Berlin. pp. 55-90. ISBN: 9783110282269
- Moodey, A. , Lawless, A. , Potthast, R. , Van Leeuwen, P. (2013) Nonlinear error dynamics for cycled data assimilation methods. Inverse Problems , 29 (2). pp. 25002. ISSN: 0266-5611 | doi: https://dx.doi.org/10.1088/0266-5611/29/2/025002
- Smith, P. , Thornhill, G. , Dance, S. , Lawless, A. , Mason, D. , Nichols, N. (2013) Data assimilation for state and parameter estimation: application to morphodynamic modelling. Quarterly Journal of the Royal Meteorological Society , 139 (671 Part B). pp. 314-327. ISSN: 1477-870X | doi: https://dx.doi.org/10.1002/qj.1944
- Thornhill, G. , Mason, D. , Dance, S. , Lawless, A. , Nichols, N. , Forbes, H. (2012) Integration of a 3D Variational data assimilation scheme with a coastal area morphodynamic model of Morecambe Bay. Coastal Engineering , 69 pp. 82-96. ISSN: 0378-3839 | doi: https://dx.doi.org/10.1016/j.coastaleng.2012.05.010
- Pocock, J. , Dance, S. , Lawless, A. (2011) State estimation using the particle filter with mode tracking. Computers & Fluids , 46 (1). pp. 392-397. ISSN: 0045-7930 | doi: https://dx.doi.org/10.1016/j.compfluid.2011.02.009
- Haben, S. , Lawless, A. , Nichols, N. (2011) Conditioning and preconditioning of the variational data assimilation problem. Computers & Fluids , 46 (1). pp. 252-256. ISSN: 0045-7930 | doi: https://dx.doi.org/10.1016/j.compfluid.2010.11.025
- Boess, C. , Lawless, A. , Nichols, N. , Bunse-Gerstner, A. (2011) State estimation using model order reduction for unstable systems. Computers & Fluids , 46 (1). pp. 155-160. ISSN: 0045-7930 | doi: https://dx.doi.org/10.1016/j.compfluid.2010.11.033
- Haben, S. , Lawless, A. , Nichols, N. (2011) Conditioning of incremental variational data assimilation, with application to the Met Office system. Tellus Series A: Dynamic Meteorology and Oceanography , 63 (4). pp. 782-792. ISSN: 1600-0870 | doi: https://dx.doi.org/10.1111/j.1600-0870.2011.00527.x
- Katz, D. , Lawless, A. , Nichols, N. , Cullen, M. , Bannister, R. (2011) Correlations of control variables in variational data assimilation. Quarterly Journal of the Royal Meteorological Society , 137 (656). pp. 620-630. ISSN: 1477-870X | doi: https://dx.doi.org/10.1002/qj.798 (Part A)
- Baxter, G. , Dance, S. , Lawless, A. , Nichols, N. (2011) Four-dimensional variational data assimilation for high resolution nested models. Computers & Fluids , 46 (1). pp. 137-141. ISSN: 0045-7930 | doi: https://dx.doi.org/10.1016/j.compfluid.2011.01.023
- Lawless, A. (2010) A note on the analysis error associated with 3D-FGAT. Quarterly Journal of the Royal Meteorological Society , 136 (649). pp. 1094-1098. ISSN: 1477-870X | doi: https://dx.doi.org/10.1002/qj.619
- Dance, S. , Baines, M. , Lawless, A. , Mason, D. , Nichols, N. , Scott, T. , Sweby, P. , Smith, P. , Thornhill, G. (2010) Use of data assimilation methods in coastal sediment models.
- Thornhill, G. , Scott, T. , Smith , P. , Dance, S. , Mason, D. , Nichols, N. , Baines, M. , Horsburgh, K. , Sweby, P. , Lawless, A. (2009) Progress on “Changing coastlines: data assimilation for morphodynamic prediction and predictability”.
- Nichols, N. , Baxter, G. , Dance, S. , Lawless, A. (2009) Issues in high resolution data assimilation.
- Lawless, A. , Nichols, N. , Boess, C. , Bunse-Gerstner, A. (2008) Approximate Gauss-Newton Methods for optimal state estimation using reduced-order models. International Journal for Numerical Methods in Fluids , 56 (8). pp. 1367 -1373. ISSN: 0271-2091 | doi: https://dx.doi.org/10.1002/fld.1629
- Lawless, A. , Nichols, N. , Boess, C. , Bunse-Gerstner, A. (2008) Using model reduction methods within incremental four-dimensional variational data assimilation. Monthly Weather Review , 136 (4). pp. 1511-1522. ISSN: 0027-0644 | doi: https://dx.doi.org/10.1175/2007MWR2103.1
- Scott, T. , Smith, P. , Dance, S. , Mason, D. , Baines, M. , Nichols, N. , Horsburgh, K. , Sweby, P. , Lawless, A. (2008) Data assimilation for morphodynamic prediction and predictability. Coastal Engineering 2008 Proceedings of the 31st International Conference. , 3. World Scientific pp. 2386-2398. | doi: https://dx.doi.org/10.1142/9789814277426_0197
- Bannister, R. , Katz, D. , Cullen, M. , Lawless, A. , Nichols, N. (2008) Modelling of forecast errors in geophysical fluid flows. International Journal for Numerical Methods in Fluids , 56 (8). pp. 1147-1153. ISSN: 0271-2091 | doi: https://dx.doi.org/10.1002/fld.1618
- Scott, T. , Smith, P. , Dance, S. , Mason, D. , Nichols, N. , Baines, M. , Horsburgh, K. , Sweby, P. , Lawless, A. (2007) Progress on Changing coastlines: data assimilation for morphodynamic prediction and predictability.
- Bannister, R. , Katz, D. , Cullen, M. , Lawless, A. , Nichols, N. (2007) Modelling of forecast errors in geophysical fluid flows. Proceedings of the Ninth International ICFD Conference on Numerical Methods for Fluid Dynamics, March 26 – 29, 2007. ICFD , Reading.
- Lawless, A. , Nichols, N. , Boess, C. , Bunse-Gerstner, A. (2007) Approximate Gauss-Newton methods using reduced order models. Proceedings of the Ninth International ICFD Conference on Numerical Methods for Fluid Dynamics, March 26 – 29, 2007. ICFD , Reading.
- Baxter, G. , Dance, S. , Lawless, A. , Nichols, N. , Ballard, S. (2007) Towards Multi-scale Data Assimilation for High Resolution Nested Models. Proceedings of the Ninth International ICFD Conference on Numerical Methods for Fluid Dynamics, March 26 – 29, 2007. ICFD , Reading.
- Watkinson, L. , Lawless, A. , Nichols, N. , Roulstone, I. (2007) Weak constraints in four-dimensional variational data assimilation. Meteorologische Zeitschrift , 16 (6). pp. 767-776. | doi: https://dx.doi.org/10.1127/0941-2948/2007/0249
- Gratton, S. , Lawless, A. , Nichols, N. (2007) Approximate Gauss-Newton methods for nonlinear least squares problems. SIAM Journal on Optimization (SIOPT) , 18 (1). pp. 106-132. ISSN: 1052-6234 | doi: DOI:10.1137/050624935
- Lawless, A. , Gratton, S. , Nichols, N. (2006) An investigation of the convergence of incremental 4D-Var.
- Lawless, A. and Nichols, N. (2006) Inner loop stopping criteria for incremental four-dimensional variational data assimilation. Monthly Weather Review , 134 pp. 3425-3435.
- Lawless, A. , Gratton, S. , Nichols, N. (2005) An investigation of incremental 4D-Var using non-tangent linear models. Quarterly Journal of the Royal Meteorological Society , 131 (606). pp. 459-476. ISSN: 1477-870X
- Lawless, A. , Gratton, S. , Nichols, N. (2005) Approximate iterative methods for variational data assimilation. International Journal For Numerical Methods In Fluids , 47 (10-11). pp. 1129-1135.
- Watkinson, L. , Lawless, A. , Nichols, N. , Roulstone, I. (2005) Variational data assimilation for Hamiltonian problems. International Journal For Numerical Methods In Fluids , 47 (10-11). pp. 1361-1367.
- Lawless, A. , Gratton, S. , Nichols, N. (2004) Approximate iterative methods for variational data assimilation. ICFD
- Stanton, L. , Lawless, A. , Nichols, N. , Roulstone, I. (2004) Variational data assimilation for Hamiltonian problems. ICFD
- Lawless, A. , Nichols, N. , Ballard, S. (2003) A comparison of two methods for developing the linearization of a shallow-water model. Quarterly Journal of the Royal Meteorological Society , 129 (589). pp. 1237-1254. ISSN: 1477-870X | doi: https://dx.doi.org/10.1256/qj.02.75
- Lawless, A. and Nichols, N. (2003) The convergence of incremental 4D-Var using non-tangent linear models.. In: Cote, . , (eds.) Research activities in atmospheric and oceanic modelling. WMO CAS/JSG Working Group on Numerical Experimentation pp. 01-17 + 01-18.