Verifying and assessing the performance of the perturbation strategy in polynomial chaos ensemble forecasts of the circulation in the Gulf of Mexico
KAUST DepartmentComputer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Applied Mathematics and Computational Science Program
Online Publication Date2018-09-05
Print Publication Date2018-11
Permanent link to this recordhttp://hdl.handle.net/10754/630538
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AbstractWe present an analysis of two recent efforts aimed at quantifying the uncertainties in a 30-day HYbrid Coordinate Ocean Model forecast of the circulation in the Gulf of Mexico, with particular emphasis on the separation of Loop Current Eddy Franklin, using Polynomial Chaos methods. The analysis herein explores whether the model perturbations lead to realistic representation of the uncertainty in the Gulf Circulation. Comparisons of model output with Sea Surface Height and current mooring data show that the observational data generally falls within the envelope of the ensemble and that the modal decomposition delivers “realistic” perturbations in the Loop Current region. We use information theory metrics to quantify the information gain and the computational trade-offs between different wind and initial conditions perturbation modes. The relative entropy measures indicate that two modes for initial condition perturbations are enough, in our model configuration, to represent the uncertainty in the Loop Current region; while two modes for wind forcing perturbations are necessary in order to estimate the uncertainty in the coastal zone. The ensemble statistics are then explored using the Polynomial Chaos surrogate and the newly developed contour boxplot methods.
CitationWang S, Li G, Iskandarani M, Le Hénaff M, Knio OM (2018) Verifying and assessing the performance of the perturbation strategy in polynomial chaos ensemble forecasts of the circulation in the Gulf of Mexico. Ocean Modelling 131: 59–70. Available: http://dx.doi.org/10.1016/j.ocemod.2018.09.002.
SponsorsThis research was made possible in part by a grant from The Gulf of Mexico Research Initiative, by the US Department of Energy (DOE), Office of Science, Office of Advanced Scientific Computing Research, under Award Number DE- SC0008789, and by the National Science Foundation under Grant number 1639722 (an EarthCube-supported project). This research was conducted in collaboration with and using the resources of the University of Miami Center for Computational Science, as well as the resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231. M. Le Hénaff received partial support for this work from the NOAA Quantitative Observing System Assessment Program (QOSAP, grant NA15OAR4320064) and the base funds of the NOAA Atlantic Oceanographic and Meteorological Laboratory. Data are publicly available through the Gulf of Mexico Research Initiative Information & Data Cooperative (GRIIDC) at https://data.gulfresearchinitiative.org (doi:10.7266/N77H1GNF, doi:10.7266/N7QZ2813). This study has been conducted using E.U. Copernicus Marine Service Information. The mapped altimetry products were produced by Ssalto/Duacs and distributed by the Copernicus Marine Environment Marine Service (http://marine.copernicus.eu).