The relationship between satellite and meteorological model-derived winds with those from ocean buoys within the Bay of Biscay

Output from the global forecast system (GFS) meteorological model and measurements derived from the QuikSCAT satellite are investigated, comparing them with in situ data obtained from moored buoys. In order to undertake these comparisons, one year (April 2003–March 2004) of wind data from the GFS model and from the QuikSCAT satellite were co-located with the in situ data; retaining spatial differences of less than 0.4° longitude−0.5° latitude and temporal differences of <30 min. The buoy data were converted from 3 m to 10 m height above the sea surface by means of the logarithmic profile method. To investigate the agreement between the data pairs, correlation coefficients were computed; likewise linear regression models were fitted to the different data sets. The accuracy and precision of the QuikSCAT and GFS model were estimated through the computation of the bias and the RMS differences (RMSD). The statistical results reflect a better agreement between the QuickSCAT and the buoy winds (r > 0.68 for the wind speed, r > 0.86 for the direction), rather than between the GFS and the buoy winds (r > 0.61 for the wind speed, r > 0.74 for the direction). Similarly, there is higher accuracy and precision in the QuikSCAT measurements (RMSD < 2.23 m s−1 for the wind speed, RMSD < 48.3° for the direction). Nonetheless, the GFS still represents a good agreement with the winds obtained from the buoys. In both cases, there is better agreement and higher accuracy and precision in the open ocean waters (0.82 < r < 0.98), than near to the coast (0.61 < r < 0.91), both for wind speed and direction.