Variations in the Malvinas Current volume transport since October 1992

• Published in: Journal of Geophysical Research 2009-02, Vol.114 (C2), p.n/a
• Main Authors: Spadone, Aurélie, Provost, Christine
• Format: Article
• Language: English
• Subjects: Earth Sciences; Earth, ocean, space; Exact sciences and technology; Geophysics; interannual variations; Malvinas Current; Marine; Physics; Sciences of the Universe; transport
• ISSN: 0148-0227; 2169-9275; 2156-2202; 2169-9291
• DOI: 10.1029/2008JC004882

We present a set of new current meter measurements collected to monitor the Malvinas Current (MC) near its merger with the Brazil Current at 40–41°S from December 2001 to February 2003 below a Jason‐1 altimeter track. These measurements are compared to former measurements obtained 8 years earlier at the same location; they also provide new information on the core of the MC on the continental slope above the 1000‐m isobath where a mooring had been previously lost. There, most of the velocity variation is along‐isobath (80% of the variance) and shows a significant annual cycle. The two data sets provide coherent means and statistical parameters on the vertical structure of the flow. A 14‐year‐long time series of MC volume transport is derived using satellite altimetry. The good correlation between the altimetry‐derived transport and the transport estimated from the current meter data persists in time (over 0.7 for each measurement period). A spectacular shift in the spectral composition of transport variations was observed: from 1992 until the end of 1997 transport variations occurred at rather short periods (50–90 days and to some degree around 180 days) whereas, after year 2000, longer periods including a seasonal cycle predominated. Altimetry‐derived anomalies of surface geostrophic velocities along the core of the MC show a similar shift in spectral composition suggesting a remote‐forcing origin.