On the year-to-year changes of the Iberian Poleward Current

Abstract

The results of a 20 year high-resolution simulation that spans from 1989 to 2008 are analyzed to study the year-to-year changes of the Iberian Poleward Current (IPC), and its effects on the temperature and salinity variability on the Western Iberian Margin. The model results are compared with satellite data and with data measured at two moored multiparametric buoys. The model reproduces the events of strong sea surface temperature (SST) anomalies described in the literature, for the northern and western coasts, and it helps to explain the connection between the IPC intensity, temperature, and salinity. By analyzing some specific winters, with different characteristics, it is confirmed that years of stronger IPC result in higher transport of heat and salt, and the development of positive anomalies of temperature and salinity. However, local air-sea fluxes are also important and explain the temperature and salinity anomalies observed in some of the winters. The interplay between the IPC transport, or advection, and the local heat and salt fluxes explain why the temperature and salinity anomalies may be in antiphase or uncorrelated with the IPC magnitude. It is shown that from November to January, the IPC magnitude depends mostly on the intensity of the southerly winds, and it has a significant negative correlation with the NAO index.