2001), 25-day period large-scale oscillations in the Argentine basin revealed by the TOPEX/Poseidon altimeter

• Main Authors: Lee-lueng Fu, Benny Cheng, Bo Qiu
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Argentine; Southern Ocean; Zapiola; South Atlantic Ocean
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.508.950; http://www.soest.hawaii.edu/oceanography/bo/FCQ01.pdf

The measurement of the global sea surface height made by the TOPEX/Poseidon satellite has provided the first synoptic view of large-scale oceanic variability at intraseasonal scales from weeks to months. Areas of significant intraseasonal variability were found primarily in the Tropics and the high-latitude oceans, the Southern Ocean in particular. The focus of the paper is the finding of large-scale oscillations at a period of 25 days in the Argentine Basin of the South Atlantic Ocean. These oscillations exhibit a dipole pattern of counterclockwise rotational propagation centered at 458S, 3178E over the Zapiola Rise. The scale of the dipole is about 1000 km. The peak-to-trough amplitude is on the order of 10 cm. The amplitude of these oscillations has large seasonal-to-interannual variations. These oscillations are shown to be associated with a free barotropic mode of the basin as a solution to a linearized barotropic vorticity equation. Closed f/H contours provide a mechanism for the confinement of the waves to the topographic feature of the Zapiola Rise. Results from a numerical model simulation reproduced the patterns of the observed oscillations. The resultant mass transport variability is on the order of 50 Sv (Sv [ 106 m3 s21). Deep current meters in the Argentine Basin reveal signals consistent with the altimetry observations. 1.