SST subseasonal variability in the central Benguela upwelling system as inferred from satellite observations (1999–2009)

• DOI: 10.1002/jgrc.20287
• Publication Date: 2013-06-29T12:19:00Z
• Authors: Katerina Goubanova; Séréna Illig; Eric Machu; Véronique Garçon; Boris Dewitte
• Keywords: Madden–Julian oscillation; Wind Stress; Ekman transport; Forcing (mathematics); Empirical orthogonal functions; Middle latitudes; Kelvin wave; Seasonality

Subseasonal variability of Sea Surface Temperature (SST) in the central Benguela upwelling system is investigated using TMI satellite‐derived data over period 1999–2009. Spatial patterns and time‐frequency characteristics subseasonal are documented based on Empirical Orthogonal Functions (EOF) decomposition wavelet analysis. Despite land contamination satellite within approximately 100 km off coast first EOF SST anomalies allows characterizing coastal at scale. Two regimes evidenced: a submonthly (2–30 days) regime with dominant 11 days oscillation lower frequency intraseasonal (30–90 61 oscillation. Both modulated, to large extent, by local surface wind stress consistent Ekman dynamics. The seasonality relationship between for (intraseasonal) characterized marked semiannual (annual) cycle, which explained terms impact seasonal change upper ocean stratification vertical advection process. wind‐driven shown be associated eastward propagating disturbances midlatitudes corresponding wave number 4. results also suggest an important role Antarctic Oscillation modulating variability. equatorial Kelvin waves order discuss possible remote oceanic forcing along system.