Probabilistic relationships between wind and surface water circulation patterns in the SE Bay of Biscay

• DOI: 10.1007/s10236-015-0871-5
• Publication Date: 2015-09-11T08:41:54Z
• Authors: Lohitzune Solabar...; Anna Rubio; Mar Cárdenas; Sonia Castanedo; Ganix Esnaola; Fernando J. Méndez; Raúl Medina; Luis Ferrer
• Keywords: HF RADAR DATA; CURRENTS; DYNAMICS; 0106 biological sciences; SLOPE; High-frequency radar; Wind-induced circulation; SOUTHERN BAY; OIL-SPILL; 01 natural sciences; VARIABILITY; 13. Climate action; Shelf slope circulation; Ocean surface currents; SOUTHEASTERN BAY; RECONSTRUCTION; 14. Life underwater; Iberian Poleward Current; TEMPERATURE; Clustering technique

Non-linear K-means classification algorithm was used to obtain a comprehensive description of the winds and high-frequency radar-derived currents in the SE Bay of Biscay (study area), taking into account a wide range of scales, from several days to interannual variability. The results in the study area show that in summer, a stronger variability in winds and surface currents can be expected, while in winter, intense southwesterly winds and a cyclonic circulation prevail. In addition to the seasonal component of the currents, a significant spatial variability in terms of current patterns and a temporal variability at shorter and interannual scales were also identified, highlighting the complexity of the surface current dynamics. Moreover, the probabilistic relationships between wind and current patterns were explored, obtaining conditional probabilities. Most of the surface current patterns are clearly related to specific wind patterns that are recurrent in the study area. However, other common current patterns are not so clearly related to specific wind conditions. The presence of a seasonal slope current (Iberian Poleward Current, IPC) is one of the most relevant features of the local circulation. An IPC occurrence time series based on Sea Surface Temperature satellite imagery was used to obtain conditional probabilities with the high-frequency radar surface current patterns, showing a relation between the strongest IPC events and closed cyclonic currents, which are not linked to specific winds.