Satellite observations of an annual cycle in the Agulhas Current

• Published in: Geophysical research letters Vol. 39; no. 15
• Main Authors: Krug, M., Tournadre, J.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 16.08.2012; American Geophysical Union; John Wiley & Sons, Inc
• Subjects: Agulhas Current; Altimetry; annual cycle; Atmospheric sciences; climate; cross-stream; Earth sciences; Earth, ocean, space; Exact sciences and technology; Oceanography; Physical oceanography; Remote sensing; satellite observations; Sciences of the Universe; Sea surface temperature; seasonal; Seasonal variations; SST; variability; Agulhas current; ocean currents; high frequency; Position; Space remote sensing; streams; coordinates; Summer; Satellite observation; exhibits; Sea surface temperature; velocity; variability; trajectory; in situ; Ocean model; drill cores; annual variations; Frequency spectrum; Western boundary current; seasonal variations; flow; altimetry; Geostrophic current
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2012GL052335

Ocean models show an annual cycle in the Agulhas Current transport which has not yet been confirmed in analyses of in‐situ or satellite observations. A cross‐stream coordinate approach is used to study the variability of the Agulhas Current from 18 years of along‐track altimetry and merged altimetry and close to 7 years of high frequency Sea Surface Temperature (SST) observations. While the position and width of the Agulhas Current's dynamical core do not display an annual cycle, the geostrophic current speed at the current's core exhibits distinct seasonal variations, with a stronger flow observed in austral summer. The annual cycle dominates the frequency spectra of the current's core geostrophic velocities. Key Points There is an annual cycle in the Agulhas Current The annual cycle dominates the variability in the Agulhas Current A cross‐stream approach is needed for Agulhas Current variability