[en] An ensemble of 250 model setups covering the Mediterranean Sea is built by perturbing various parameters: the bathymetry, the initial conditions, atmospheric forcing fields (air temperature, cloud coverage, wind), and internal model parameters (diffusion coefficients). The ensemble is then forwarded in time using the GHER hydrodynamic model, allowing to obtain information about the expected error associated with the forecast in a natural way. The evolution of this error is analyzed. In particular, we examine the time evolution and stationarity of its spatial average, and the spatial distribution of the error at different instants, by means of its first to fourth order moments, and of empirical orthogonal functions. We verify whether the a posteriori error distribution is Gaussian using the Anderson-Darling test. From these results, we are able to assess what parameters and forcing fields are most critical for the forecast. Qualitative conclusions are obtained throughout the text, in accordance with our expectations. Moreover, quantitative estimations of the expected error are also given. (C) 2008 Elsevier Ltd. All rights reserved.
Research center :
Centre Interfacultaire de Recherches en Océanologie - MARE -GHER
Disciplines :
Earth sciences & physical geography
Author, co-author :
Vandenbulcke, Luc ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Rixen, M.
Alvera Azcarate, Aïda ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > GeoHydrodynamics and Environment Research (GHER)
Barth, Alexander ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Océanographie physique
Beckers, Jean-Marie ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Océanographie physique
Language :
English
Title :
An analysis of the error space of a high-resolution implementation of the GHER hydrodynamic model in the Mediterranean Sea
Alvera-Azcárate A., Barth A., Ben BouallFgue Z., Rixen M., and Beckers J.-M. Forecast Verification of a 3D model of the Ligurian Sea. The use of Discrete Wavelet Transforms in the skill assessment of spatial forecasts. Journal of Marine Systems 65 (2007) 460-483
Alvera-Azcárate, A., 2004. Forecast verification of a 3d model of the Mediterranean Sea. Analysis of model results and observations using wavelets and Empirical Orthogonal Functions. Ph.D. Thesis, Université de Liege, 263 pp.
Anderson T.W., and Darling D.A. Asymptotic theory of certain "goodness-of-fit" criteria based on stochastic processes. Annals of Mathematical Statistics 23 (1952) 193-212
Auclair F., Marsaleix P., and De Mey P. Space-time structure and dynamics of the forecast error in a coastal circulation model of the Gulf of Lions. Dynamics of Atmospheres and Oceans 36 (2003) 309-346
Auclair F., Marsaleix P., and Estournel C. The penetration of the Northern Current over the Gulf of Lions (Mediterranean) as a downscaling problem. Oceanologica Acta 24 (2001) 529-544
Barth A., Alvera-Azcárate A., Beckers J.-M., Rixen M., and Vandenbulcke L. Multigrid state vector for data assimilation in a two-way nested model of the Ligurian Sea. Journal of Marine Systems (2006)
Barth, A., 2004. Assimilation of sea surface temperature and sea surface height in a two-way nested primitive equation model of the Ligurian Sea. Ph.D. Thesis, Université de Liege, 202 pp.
Beckers J.-M., Rixen M., Brasseur P., Brankart J.-M., Elmoussaoui A., Crépon M., Herbaut C., Martel F., Van den Berghe F., Mortier L., Lascaratos A., Drakopoulos P., Korres P., Pinardi N., Masetti E., Castellari S., Carini P., Tintore J., Alvarez A., Monserrat S., Parrilla D., Vautard R., and Speich S. Model intercomparison in the Mediterranean. The MedMEx simulations of the seasonal cycle. Journal of Marine Systems (2002) 215-251
Beckers J., Brasseur P., and Nihoul J. Circulation of the western Mediterranean: from global to regional scales. Deep-Sea Research 44 3-4 (1997) 531-549
Beckers J. Application of a 3D model to the Western Mediterranean. Journal of Marine Systems 1 (1991) 315-332
Bertino L., Evensen G., and Wackernagel H. Sequential data assimilation techniques in oceanography. International Statistical Review 17 (2003) 223-241
Bozzano R., Siccardi A., Schiano M.E., Borghini M., and Castellari S. Comparison of ecmwf surface meteorology and buoy observations in the ligurian sea. Annales Geophysicae 22 (2004) 317-330
Brasseur P., Beckers J.-M., Brankart J.-M., and Schoenauen R. Seasonal temperature and salinity fields in the Mediterranean Sea: climatological analyses of an historical data set. Deep-Sea Research 43 2 (1996) 159-192
Broquet G., Brasseur P., Rozier D., Brankart J.-M., and Verron J. Estimation of model errors generated by atmospheric forcings for ocean data assimilation: experiments in a regional model of the Bay of Biscay. Ocean Dynamics 58 (2008) 1-17
Cane M., Kaplan A., Miller R., Tang B., Hackert E., and Busalacchi A. Mapping tropical Pacific sea level: data assimilation via a reduced state space Kalman filter. Journal of Geophysical Research 101 C10 (1996) 22599-22617
Chiles J.P., and Delfiner P. Geostatistics: Modeling Spatial Uncertainty (1999), Wiley
Duynkerke P., and Teixeira J. Comparison of the ecmwf reanalysis with fire i observations: diurnal variation of marine stratocumulus. Journal of Climate 14 (2000) 1466-1478
Evensen G. Sequential data assimilation with a nonlinear quasi-geostrophic model using Monte Carlo methods to forecast error statistics. Journal of Geophysical Research 99 NO. C5 (1994) 10143-10162
Evensen G. The Ensemble Kalman Filter: theoretical formulation and practical implementation. Ocean Dynamics 53 (2003) 343-367
Haines K. Assimilation of satellite altimetry in ocean models. In: Pinardi N., and Woods J.D. (Eds). Ocean Forecasting Conceptual Basis and Applications (2002), Springer-Verlag, Berlin, Heidelberg, New York 472
Halpern D., Freilch M.H., and Waller R.A. Ecmwf and ers-1 surface winds over the arabian sea during July 1995. Journal of Physical Oceanography 29 (1999) 1619-1623
Lermusiaux, P., Haley, P., Leslie, W., Logutov, O., September 2007. Ocean predictions for rapid environmental assessment: modelers, data and modeling systems. In: Nato Undersea Research Center: Rapid Environmental Assessment Conference, La Spezia, Italy, keynote oral presentation. .
Lermusiaux P. Uncertainty estimation and prediction for interdisciplinary ocean dynamics. Journal of Computational Physics 217 (2006) 176-199
Mourre B., De Mey P., Lyard F., and Le Provost C. Assimilation of sea level data over continental shelves: an ensemble method for the exploration of model errors due to uncertainties in bathymetry. Dynamics of Atmospheres and Oceans 38 (2007) 93-121
Nihoul J.C.J., Deleersnijder E., and Djenidi S. Modelling the general circulation of shelf seas by 3D k - ε{lunate} models. Earth-Science Reviews 26 (1989) 163-189
Pham D.T., Verron J., and Roubaud M.C. A singular evolutive extended Kalman filter for data assimilation in oceanography. Journal of Marine Systems 16 3-4 (1998) 323-340 (October)
Robinson A., Wayne G., Theocharis A., and Lascaratos A. Mediterranean sea circulation. In: Steele J., Turekian K., and Thorpe S. (Eds). Encyclopedia of Ocean Sciences (2001), Academic Press
She J., Berg P., and Berg J. Bathymetry impacts on water exchange modelling through the Danish Straits. Journal of Marine Systems 65 (2007) 450-459
Smith W.H.F., and Sandwell D.T. Global sea floor topography from satellite altimetry and ship depth soundings. Science 277 (1997) 1956-1962
Talagrand O. Assimilation of observations, an introduction. Journal of the Meteorological Society of Japan 75 (1997) 191-209
Vallis G. Mechanisms and parameterizations of geostrophic adjustment and a variational approach to balanced flow. Journal of Atmospheric Science 49 (1992) 1144-1160
Vandenbulcke, L., Barth, A., Rixen, M., Alvera-Azcarate, A., Ben Bouallegue, Z., Beckers, J., 2006. Study of the combined effects of data assimilation and grid nesting in ocean models - application to the Gulf of Lions. Ocean Science 2, 213-222. .