Skill tests of three-dimensional tidal currents in a global ocean model: A look at the North Atlantic

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: G. Timko, Patrick, Arbic, Brian K., Richman, James G., Scott, Robert B., Metzger, E. Joseph, Wallcraft, Alan J.
• Other Authors: Center for Ocean-Atmospheric Prediction Studies (COAPS), Florida State University Tallahassee (FSU), Department of Earth and Environmental Sciences Ann Arbor, University of Michigan Ann Arbor, University of Michigan System-University of Michigan System, Centre for Applied Marine Sciences, Marine Science Laboratories, Oceanography Division, Stennis Space Center, Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institute of Geophysics Austin (IG), University of Texas at Austin Austin
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2012
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Greenwich; North Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-00738922; https://doi.org/10.1029/2011JC007617

International audience We present and apply several skill tests to assess tidal currents generated within a global ocean model compared to an archive of current meter records spanning 40 years. Within the North Atlantic we have identified over 1800 velocity records available for comparison to model output. The skill tests identify those regions where tidal ellipse parameters (semi-major/minor axis, inclination and Greenwich phase) fall within 95% confidence intervals derived from observations. Additional skill tests examine the vertical and horizontal structure of the tidal currents using the correlation and root mean square error between the observations and model. The skill tests account for grid misrepresentation within the model by comparing model values in a local 9-point neighborhood. Both the three-dimensional structure of model tidal currents and barotropic model tidal currents are compared to the altimetry based barotropic model TPXO 7.2. Our results indicate that the non-data assimilative ocean model performance is comparable to TPXO 7.2. The semi-major axes of the semi-diurnal constituents lie within the 95% confidence intervals between 40% and 60% of the time in some regions of the North Atlantic. The performance degrades when all tidal ellipse parameters are considered. Root mean square errors between the model and observations distributed through the water column are generally less than 1 cm s−1 representing an error of less than ∼10% for constituent M2. The model tides also exhibit high correlation with observations in the horizontal planes. The skill tests could be adapted to other sets of observations and other models.