On deep-current and hydrographic observations from a mudwave region and elsewhere in the Argentine Basin

Weatherly, Georges L.

doi:10.1016/0967-0645(93)90042-l

Cited by 70 publications

(48 citation statements)

References 18 publications

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“…Remarkably, the Zapiola anticyclone is surrounded by one of the most eddying region of the global ocean, namely the confluence between the Nord-Brazil current and the Malvinas current (see Figure 2b). Perhaps surprisingly, the Zapiola anticyclone has only been discovered rather lately, and almost simultaneously with in situ measurement [Weatherly, 1993;Saunders and King, 1995], numerical ocean models [de Miranda et al, 1999], and in theoretical studies [Dewar, 1998]. Also striking is the strong interannual variability of the Zapiola anticyclone transport which has recently been reported from 15 years of altimetric measurements [Saraceno et al, 2009].…”

Section: Intrinsic Variability Of the Zapiola Anticyclonementioning

confidence: 97%

Stochastic variability of oceanic flows above topography anomalies

Venaille

Sommer

Molines

et al. 2011

Geophys. Res. Lett.

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We describe a stochastic variability mechanism which is genuinely internal to the ocean, i.e. not due to fluctuations in atmospheric forcing. % The key ingredient is the existence of closed contours of bottom topography surrounded by a stirring region of enhanced eddy activity. This configuration leads to the formation of a robust but highly variable vortex above the topography anomaly. The vortex dynamics integrates the white noise forcing of oceanic eddies into a red noise signal for the large scale volume transport of the vortex. The strong interannual fluctuations of the transport of the Zapiola anticyclone ($\sim 100 \ Sv$) in the Argentine basin are argued to be partly due to such eddy-driven stochastic variability, on the basis of a 310 years long simulation of a comprehensive global ocean model run driven by a repeated-year forcing

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Section: Intrinsic Variability Of the Zapiola Anticyclonementioning

confidence: 97%

Stochastic variability of oceanic flows above topography anomalies

Venaille

Sommer

Molines

et al. 2011

Geophys. Res. Lett.

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“…Several factors have been suggested to explain the differences. Weatherly (1993) argued that the different peak frequencies at his sites 4 and 5 could be reconciled by accounting for a Doppler shift in the period of a single Rossby wave (with a basic period of about 23 days), due to the background flow being of opposite sign at the two locations. However, after correcting for a sign error (G. Weatherly 2005, personal communication), the direction of the flow at the two sites does not appear to support such an interpretation: accounting for a Doppler shift at site 5, the westward flow would actually be consistent with a free-oscillation period higher than 28 days, rather than lower.…”

Section: Introductionmentioning

confidence: 99%

“…Weatherly (1993) analyzed current-meter records from a few moorings in the Argentine Basin and found evidence for barotropic variability with periods between 20 and 30 days. More specifically, he found evidence for a 28-day oscillation at the site closest to Zapiola Rise (his site 5; W5 in Fig.…”

Section: Introductionmentioning

confidence: 99%

Multiple Oscillatory Modes of the Argentine Basin. Part I: Statistical Analysis

Weijer

Vivier

Gille

et al. 2007

Journal of Physical Oceanography

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Observations of the sea surface height in the Argentine Basin indicate that strong variability occurs on a time scale of 20Ϫ30 days. The aim of this study is to determine the physical processes responsible for this variability. First, results are presented from two statistical techniques applied to a decade of altimetric data. A complex empirical orthogonal function (CEOF) analysis identifies the recently discovered dipole mode as the dominant mode of variability. A principal oscillation pattern (POP) analysis confirms the existence of this mode, which has a period of 25 days. The second CEOF displays a propagating pattern in the northern Argentine Basin, plus a rotating dipole in the southwest corner. The POP analysis identifies both patterns as individual modes, with periods of 30 and 20 days, respectively. Second, the barotropic normal modes of the Argentine Basin are studied, using a shallow-water model capturing the full bathymetry of the basin. Coherences between the spatial patterns of these modes and altimeter data suggest that several of the basin modes are involved in the observed variability. This analysis implies that the 20-day mode detected by recent bottom-pressure measurements is a true barotropic mode. However, the 25-day variability, as found in altimeter data, cannot be directly attributed to the excitation of a free Rossby basin mode. This study indicates that the results of several apparently conflicting observations of the flow variability in the Argentine Basin can be reconciled by assuming that multiple basin modes are involved.

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“…This is a region characterized with very high degree of sea surface height variability. Part of it is due to the intense eddy and frontal activity resulting from confluent currents, part of it has been identified in several measurements coming from altimetry (Fu et al, 2001), current meters (Weatherly, 1993) and pressure gauges (Hughes et al, 2007), as a barotropic oscillation with a 20-30 days period. Most recently, different statistical techniques applied to a decade of weekly SSH maps suggests that actually multiple basin modes are present in the Argentine basin (Weijer et al, 2007a).…”

Section: Barotropic Rossby Basin Modesmentioning

confidence: 99%

Stability of large-scale oceanic flows and the importance of non-local effects

Hristova¹

2009

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On deep-current and hydrographic observations from a mudwave region and elsewhere in the Argentine Basin

Cited by 70 publications

References 18 publications

Stochastic variability of oceanic flows above topography anomalies

Stochastic variability of oceanic flows above topography anomalies

Multiple Oscillatory Modes of the Argentine Basin. Part I: Statistical Analysis

Stability of large-scale oceanic flows and the importance of non-local effects

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