TY - JOUR T1 - Surface currents in the Alderney Race from high-frequency radar measurements and three-dimensional modelling A1 - Lopez,G. A1 - Bennis,Anne-Claire A1 - Barbin,Y. A1 - Sentchev,A. A1 - Benoit,L. A1 - Marié,Louis AD - Morphodynamique Continentale et Côtière (M2C), CNRS UMR 6143, Univ. Caen Normandie, 14000 Caen, France AD - Retired from Institut Méditerranéen d’Oceanologie (MIO), CNRS UMR 7294, IRD, Univ. Toulon, Univ. Aix-Marseille, 83041, Toulon, France AD - Laboratory of Oceanology and Geosciences, University Littoral Côte d’Opale, Univ. Lille, CNRS UMR 8187 LOG, Wimereux 62930, France AD - Laboratoire d’Océanographie Physique et Spatiale (LOPS), CNRS UMR 6523, Univ. Brest, Ifremer, IRD, 29280 Plouzané, France UR - https://doi.org/10.1098/rsta.2019.0494 DO - 10.1098/rsta.2019.0494 KW - HF radar KW - surface current KW - Alderney Race KW - MARS 3D KW - WW3 KW - high-frequency radar N2 - Two weeks of high-frequency radar measurements collected at the Alderney Race are compared with the results of a three-dimensional fully coupled wave–current model. Spatial current measurements are rare in this site, otherwise well investigated through modelling. Thus, the radar measurements offer a unique opportunity to examine the spatial reliability of numerical results, and can help to improve our understanding of the complex currents in the area. Comparison of observed and modelled surface current velocities showed a good agreement between the methods, represented by root mean squared errors ranging from 14 to 40 cm s−1 and from 18 to 60 cm s−1 during neap and spring tides, respectively. Maximum errors were found in shallow regions with consistently high current velocities, represented by mean neap and spring magnitudes of 1.25 m s−1 and 2.7 m s−1, respectively. Part of the differences between modelled and observed surface currents in these areas are thought to derive from limitations in the k-epsilon turbulence model used to simulate vertical mixing, when the horizontal turbulent transport is high. In addition, radar radial currents showed increased variance over the same regions, and might also be contributing to the discrepancies found. Correlation analyses yielded magnitudes above 0.95 over the entire study area, with better agreement during spring than during neap tides, probably because of an increase in the phase lag between radar and model velocities during the latter. Y1 - 2020/08 PB - The Royal Society JF - Philosophical Transactions Of The Royal Society A-mathematical Physical And Engineering Sciences SN - 1364-503X VL - 378 IS - 2178 ID - 75516 ER -