Global sensitivity analysis in an ocean general circulation model: a sparse spectral projection approach

Polynomial Chaos (PC) expansions are used to propagate parametric uncertainties in an ocean general circulation model. The computations focus on shorttime, high-resolution simulations of the Gulf of Mexico (GOM), using the HYbrid Coordinate Ocean Model (HYCOM), with wind stresses corresponding to hurricane Ivan. A sparse quadrature approach is used to determine the PC coefficients which provides a detailed representation of the stochastic model response. The quality of the PC representation is first examined through a systematic refinement of the number of resolution levels. The PC representation of the stochastic model response is then utilized to compute distributions of quantities of Research supported by the Office of Naval Research, Award N00014-101-0498. A. Alexanderian, J. Winokur, I. Sraj, O.M. Knio Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218 A. Srinivasan, M. Iskandarani Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149-1098 A. Srinivasan Center for Computational Science, University of Miami, Miami, FL 33149 W. C. Thacker Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, FL 33149 W. C. Thacker Atlantic Oceanographic and Meteorological Laboratory, Miami, FL 33149 Omar M. Knio (corresponding author) Department of Mechanical Engineering and Materials Science Duke University Durham, NC 27708 Tel: 919 660 5344 Fax: 919 660 8963 E-mail: [email protected] interest (QoIs), and to analyze the local and global sensitivity of these QoIs to uncertain parameters. Conclusions are finally drawn regarding limitations of local perturbations and variance-based assessment and concerning potential application of the present methodology to inverse problems and to uncertainty management.