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
- 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).
- A.M. DeGennaro and N.M. Urban, Scalable extended dynamic mode decomposition using random kernel approximation, SIAM Journal on Scientific Computing, in revision (2018).
- 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].
- 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].
- 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].
- 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].
- 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).
- 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).
- 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].
- 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]
- 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]
- 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]
- 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]
- 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]
- 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]
- 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]
- T.E. Fricker, J.E. Oakley, and N.M. Urban, Multivariate emulators with nonseparable covariance structures, Technometrics 55, 47 (2013). [journal]
- T.W. Hilton, K.J. Davis, K. Keller, and N.M. Urban, "Improving North American terrestrial CO_{2} flux diagnosis using spatial structure in land surface model residuals", Biogeosciences Discussions 10, 4607 (2013). [journal]
- 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]
- 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]
- 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]
- A. Schmittner, N.M. Urban, J.D. Shakun, N.D. Mahowald, P.U. Clark, P.J. Bartlein, A.C. Mix, and A. Rosell-MelĂ©, Climate sensitivity estimated from temperature reconstructions of the Last Glacial Maximum, Science 334, 1385 (2011). [journal] [supplement]
- 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]
- 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]
- 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]
- 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]
- 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).
- 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]
- 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]
- 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]
- 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]
- N.M. Urban and K. Keller, Complementary observational constraints on climate sensitivity, Geophysical Research Letters 36, L04708 (2009). [journal]
- 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]
- N.M. Urban and M.W. Cole, Quantum fluids in nanopores, International Journal of Modern Physics B 20, 5264 (2006). [journal]
- 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]