Nathan M. Urban


I am staff scientist in the Computational Physics and Methods group (CCS-2) at Los Alamos National Laboratory.

My research centers on computer model uncertainty quantification and global climate change from an Earth system perspective, with an emphasis on Bayesian data-model calibration, probabilistic prediction, risk assessment, and decision analysis. My research has a strong methodological focus, developing new approaches to uncertainty quantification, model reduction, and hybrid numerical-statistical modeling. A particular focus is in multi-model or model "structural" uncertainty quantification, referring to uncertainties in how models are constructed, rather than in the parameters or inputs to the models themsleves.

Publications

  1. A.M. DeGennaro, N.M. Urban, B.T. Nadiga, and T. Haut, Model structural inference using local dynamic operators, International Journal of Uncertainty Quantification, in revision (2018).
  2. A.M. DeGennaro and N.M. Urban, Scalable extended dynamic mode decomposition using random kernel approximation, SIAM Journal on Scientific Computing, in revision (2018).
  3. A. Jonko, N.M. Urban, and B. Nadiga, "Towards Bayesian hierarchical inference of equilibrium climate sensitivity from a combination of CMIP5 climate models and observational data", Climatic Change 149, 247 (2018) [journal].
  4. K.E. Bennett, J.R. Urrego-Blanco, A. Jonko, T.J. Bohn, A.L. Atchley, N.M. Urban, and R.S. Middleton, "Global sensitivity analysis of simulated water balance indicators under future climate change in the Colorado basin", Water Resources Research 54, 132 (2018) [journal].
  5. J.R. Urrego-Blanco, E.C. Hunke, N.M. Urban, N. Jeffery, A.K. Turner, J.R. Langenbrunner, and J.M. Booker, "Validation of sea ice models using an uncertainty-based distance metric for multiple model variables", Journal of Geophysical Research—Oceans 122, 2923 (2017) [journal].
  6. C.M. Little and N.M. Urban, "CMIP5 temperature biases and 21st century warming around the Antarctic coast", Annals of Glaciology 57, 69 (2016) [journal].
  7. B.T. Nadiga and N.M. Urban, Dependence of inferred climate sensitivity on the discrepancy model, Proceedings of the 6th International Workshop on Climate Informatics: CI 2016 (2016).
  8. J.A. Saenz, N. Lubbers, and N.M. Urban, Dimensionality-reduction of climate data using deep autoencoders, Proceedings of the 6th International Workshop on Climate Informatics: CI 2016 (2016).
  9. J.R. Urrego-Blanco, N.M. Urban, E.C. Hunke, A.K. Turner, and N. Jeffery, "Uncertainty quantification and global sensitivity analysis of the Los Alamos sea ice model", Journal of Geophysical Research—Oceans 121, 2709 (2016) [journal].
  10. N.M. Urban, T.J. Bralower, M. Haran, and K. Keller, A statistical interpretation of surface ocean temperature trends during the Paleocene-Eocene Thermal Maximum, in revision. [data]
  11. N.M. Urban, P.B. Holden, N.R. Edwards, R.L. Sriver, R. Olson, and K. Keller, Historical and future learning about climate sensitivity, Geophysical Research Letters, Geophysical Research Letters 41 2543 (2014). LA-UR-14-20618. [journal]
  12. J. Xiao, K.J. Davis, N.M. Urban, and K. Keller, "Uncertainty in model parameters and regional carbon fluxes: A model-data fusion approach", Agricultural and Forest Meteorology 189–190, 175 (2014). [journal]
  13. M.D. Escarra, L.T. Le, N.M. Urban, M. Oppenheimer, and C.F. Gmachl, "Quantum cascade laser-based sensing for carbon sequestration leakage monitoring", IEEE Sensors Journal 13, 2348 (2013). [journal]
  14. R. Olson, R. Sriver, W. Chang, M. Haran, N.M. Urban, and K. Keller, "What is the effect of unresolved internal climate variability on climate sensitivity estimates?", Journal of Geophysical Research—Atmospheres 118, 4348 (2013). [journal]
  15. C.M. Little, M. Oppenheimer, and N.M. Urban, "Upper bounds on twenty-first-century Antarctic ice loss assessed using a probabilistic framework", Nature Climate Change 3, 654 (2013). [journal]
  16. C.M. Little, N.M. Urban, and M. Oppenheimer, "Probabilistic framework for assessing the ice sheet contribution to sea level change", Proceedings of the National Academy of Sciences 110, 3264 (2013). [journal]
  17. T.E. Fricker, J.E. Oakley, and N.M. Urban, Multivariate emulators with nonseparable covariance structures, Technometrics 55, 47 (2013). [journal]
  18. T.W. Hilton, K.J. Davis, K. Keller, and N.M. Urban, "Improving North American terrestrial CO2 flux diagnosis using spatial structure in land surface model residuals", Biogeosciences Discussions 10, 4607 (2013). [journal]
  19. R.L. Sriver, N.M. Urban, R. Olson, and K. Keller, "Toward a physically plausible upper bound of sea-level rise projections", Climatic Change 115, 893 (2012). [journal]
  20. R. Olson, R. Sriver, M. Goes, N.M. Urban, H.D. Matthews, M. Haran, and K. Keller, A climate sensitivity estimate using Bayesian fusion of instrumental observations and an Earth System model, Journal of Geophysical Research—Atmospheres 117, D04103 (2012). [journal]
  21. P.J. Applegate, N.M. Urban, K. Keller, T.V. Lowell, B.J.C. Laabs, M.A. Kelly, and R.B. Alley, Improved moraine age interpretations through explicit matching of geomorphic process models to cosmogenic nuclide measurements from single landforms, Quaternary Research 77, 293 (2012). [journal]
  22. A. Schmittner, N.M. Urban, J.D. Shakun, N.D. Mahowald, P.U. Clark, P.J. Bartlein, A.C. Mix, and A. Rosell-Melé, Climate sensitivity estimated from temperature reconstructions of the Last Glacial Maximum, Science 334, 1385 (2011). [journal] [supplement]
  23. Y. Cui, L.R. Kump, A.J. Ridgwell, A.J. Charles, C.K. Junium, A.F. Diefendorf, K.H. Freeman, N.M. Urban, and I.C. Harding, "Slow release of fossil carbon during the Palaeocene-Eocene Thermal Maximum", Nature Geoscience 4, 481 (2011). [journal]
  24. J. Xiao, K.J. Davis, N.M. Urban, K. Keller, and N. Saliendra, Upscaling carbon fluxes from towers to the regional scale: Influence of parameter variability and land cover representation on regional flux estimates, Journal of Geophysical Research—Biogeosciences 116, G00J06 (2011). [journal]
  25. M. Haran and N.M. Urban, Discussion of 'A statistical analysis of multiple temperature proxies: are reconstructions of surface temperatures over the last 1000 years reliable?' by McShane and Wyner, Annals of Applied Statistics 5, 61 (2011). [journal]
  26. M. Goes, N.M. Urban, R. Tonkonojenkov, M. Haran, and K. Keller, The skill of different ocean tracers in reducing uncertainties about projections of the Atlantic meridional overturning circulation, Journal of Geophysical Research—Oceans 115, C12006 (2010). [journal]
  27. D.M. Ricciuto, R. Tonkonojenkov, R.D. Wilkinson, N.M. Urban, D. Matthews, K.J. Davis, and K. Keller, Assimilation of global carbon cycle observations into an Earth system model to estimate uncertain terrestrial carbon cycle parameters (2011).
  28. N.M. Urban and K. Keller, Probabilistic hindcasts and projections of the coupled climate, carbon cycle, and Atlantic meridional overturning circulation systems: A Bayesian fusion of century-scale observations with a simple model, Tellus A 62, 737 (2010). [journal]
  29. P.J. Applegate, N.M. Urban, K. Keller, and R.B. Alley, Modeling the statistical distributions of cosmogenic exposure dates from moraines, Geoscientific Model Development 2, 1407 (2010). [journal]
  30. N.M. Urban and T.E. Fricker, A comparison of Latin hypercube and grid ensemble designs for the multivariate emulation of an Earth system model, Computers & Geosciences 36, 746 (2010). [journal]
  31. A. Schmittner, N.M. Urban, K. Keller, and D. Matthews, Using tracer observations to reduce the uncertainty of ocean diapycnal mixing and climate-carbon cycle projections, Global Biogeochemical Cycles 23, GB4009 (2009). [journal]
  32. N.M. Urban and K. Keller, Complementary observational constraints on climate sensitivity, Geophysical Research Letters 36, L04708 (2009). [journal]
  33. D.E. Shai, N.M. Urban, and M.W. Cole, Structure and heat capacity of Ne and Xe adsorbed on a bundle of carbon nanotubes from Monte Carlo calculations, Physical Review B 77, 205427 (2008). [journal]
  34. N.M. Urban and M.W. Cole, Quantum fluids in nanopores, International Journal of Modern Physics B 20, 5264 (2006). [journal]
  35. N.M. Urban, S.M. Gatica, M.W. Cole, and J.L. Riccardo, Thermodynamic properties and correlation functions of Ar films on the surface of a bundle of nanotubes, Physical Review B 71, 245410 (2005). [journal]


Contact:
nurban@lanl.gov
Computational Physics and Methods (CCS-2)
Los Alamos National Laboratory
Mail Stop B265, Los Alamos, NM 87545, USA

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