The network of high frequency radars allows the monitoring of surface currents. The observation system is distributed by two areas: the one around Lisbon harbour with two stations: Cape Espichel ( 38,4155º N and 9,2167º W) and the other at São Julião (38,6745º N e 9,3264ºW). The South area has four stations: Sagres lighthouse (36,9945º N and 8,9492º W), Alfanzina lighthouse (37,0868º N and 8,4425ºW), Monte Gordo - terrace of Dunamar Hotel ( 37,1788º N and 7,4439ºW) and Huelva - Mazagon station (37,1316º N and 6,8329ºW) at Spain. Hourly observations are obtained up to 75 Km, with a spatial resolution of 1,3 Km.