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5) Other studies

by Webmaster Legos last modified Aug 25, 2020 07:08 PM

 

Survostral XBT and TSG data have been used in a wide range of scientific studies. A short selection is include here :

  • The variability of baroclinic transport across the ACC has been estimated from a combination of SR3 CTD measurements, relative to 2500m, and the temperature in the surface layer measured from Survostral XBTs. The variability of this baroclinic transport (relative to 2500m) is estimated at ~8 Sv from SURVOSTRAL data (Rintoul and Sokolov, 2001), compared to the mean transport of 147 ± 10 Sv across the SR3 section.
  • The time series of barotropic transport across the ACC has been estimated from XBTs, SR3 CTDs and satellite altimetry from 1992 onwards, based on the strong correlation between steric height variations and barotropic transport variability (Rintoul et al., 2002).
  • The time-variable position of ACC fronts has been estimated using absolute dynamic height contours from satellite altimetry. This technique can follow 3 fronts over 25 years (SAF-N, SAF-S, PF; Sallee et al., 2008) distributed online (ctoh.legos.obs-mip.fr/data/datasets/Polar_Fronts) or up to 10 ACC fronts (Sokolov and Rintoul, 2003). The tuning of these algorithms was validated in using SURVOSTRAL XBT data (Sallee et al., 2008; Auger, 2019).
  • Dynamic processes that generate deep jet instability in the CCA, were investigated using a combination of modeling, altimetric analysis and SURVOSTRAL XBT sections. Chapman and Morrow (2013) revealed that jets can "jump" between different bathymetric fracture zones. A vortex dipole develops on either side of the jets, and the variability in the dipole amplitude is well correlated with the frequencies of "jumping".
  • Improving the spatial resolution of hydrological fronts, via the lateral advection provided by altimetry. Altimetric currents horizontally stirred daily maps of low-resolution, gridded 2D T and S fields based on ISAS/CORA data in the Southern Ocean over a period of 7-15 days (Dencausse et al., 2013). This lateral advection generates a cascade of energy towards the smaller scales, which can create more turbulent and intense fronts. SURVOSTRAL high-resolution SSS and XBT measurements, with very fine-scale resolution of polar fronts, were used to validate this technique in this region of the Southern Ocean, and to derive the optimal duration of advection.
  • Lagrangian pathways of interocean exchange. SURVOSTRAL XBT sections and SR3 CTD sections have been used to validate numerical models investigating inter-ocean exchange south of Tasmania. Southern Ocean mode and intermediate waters have been tracked using numerical models starting from the 140°E section into the Indian Ocean (Koch-Larrouy et al., 2009) and into the Pacific Ocean (Hasson et al., 2011); the critical starting point of these models were validated with Survostral data.
  • Mode water properties in the Subantarctic Zone and their relation to mesoscale eddy activity have been studied using the combined Survostral XBT data with other hydrographic and altimeter data. (Herraiz‐Borreguero and Rintoul, 2010),
  • Spawning of cold-core eddies north of the SAF south of Tasmania, bring a heat deficit of -3.8 x 1019 J, and a salt deficit of -1.6 x 1012 kg north of the SAF, and contribute to a cooling and freshening of the Subantarctic zone where mode waters form (Morrow et al., 2004). The freshening is equivalent to that introduced by the northward Ekman transport (Rintoul and England, 2002), so this result highlights the important role of eddies in the transfer of low salinity water to the Sub-Antarctic Zone in southern Tasmania. The work was based on a combined analysis of altimetry and SURVOSTRAL TSG data.

 

 

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