Winter Currents Velocity and Sea Surface Temperature Anomalies Accompanying the Gulf Stream North Wall Displacements

Abstract

Based on average monthly data of the ORAS4 ocean reanalysis, the spatial distribution and values of anomalies of the ocean surface temperature and the velocity of surface currents occurring in the North Atlantic at the meridional displacements of the north wall of the Gulf Stream in January–February are determined. Gulf Stream North Wall Index data are used as data on Gulf Stream movements. The spatial distributions of anomalies corresponding to the northern and southern positions of the North Wall are based on averaging the fields of ocean surface temperature and the velocity of currents corresponding to each phase of the Gulf Stream North Wall index. It has been revealed that for meridional displacements of the North Wall of the Gulf Stream, statistically significant anomalies of the modulus of current velocity (0.03 m/s) and ocean surface temperature (1°C) are not only in the area of the Wall, but also along the entire northern boundary of the Gulf Stream. Here the value of the correlation coefficient of velocity time series with the Gulf Stream North Wall index is 0.56. As for temperature, the same coefficient is 0.50. Significant temperature anomalies (0.3°C) are found off the coast of the Iberian Peninsula and in the central part of the subtropical gyre. The values of the correlation coefficients of time series of the surface temperature and the index of the Gulf Stream in these areas are 0.48 and 0.53 respectively.