An Exchange Window for the Injection of Antarctic Intermediate Water into the South Pacific

Iudicone, Daniele; Rodgers, Keith B.; Schopp, Richard; Madec, Gurvan

doi:10.1175/jpo2985.1

Cited by 37 publications

(41 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It also implies that AAIW is not merely a denser version of SAMW, but rather that it has a distinct and independent formation process. These results are consistent with previous studies (e.g., Iudicone et al, 2007).…”

Section: Marinovsupporting

confidence: 94%

Water masses as a unifying framework for understanding the Southern Ocean Carbon Cycle

et al. 2011

View full text Add to dashboard Cite

Abstract. The scientific motivation for this study is to understand the processes in the ocean interior controlling carbon transfer across 30 • S. To address this, we have developed a unified framework for understanding the interplay between physical drivers such as buoyancy fluxes and ocean mixing, and carbon-specific processes such as biology, gas exchange and carbon mixing. Given the importance of density in determining the ocean interior structure and circulation, the framework is one that is organized by density and water masses, and it makes combined use of Eulerian and Lagrangian diagnostics. This is achieved through application to a global ice-ocean circulation model and an ocean biogeochemistry model, with both components being part of the widely-used IPSL coupled ocean/atmosphere/carbon cycle model.Our main new result is the dominance of the overturning circulation (identified by water masses) in setting the vertical distribution of carbon transport from the Southern Ocean towards the global ocean. A net contrast emerges between the role of Subantarctic Mode Water (SAMW), associated with large northward transport and ingassing, and Antarctic Intermediate Water (AAIW), associated with a much smaller export and outgassing. The differences in their export rate reflects differences in their water mass formation processes. For SAMW, two-thirds of the surface waters are provided as Correspondence to: D. Iudicone (iudicone@szn.it) a result of the densification of thermocline water (TW), and upon densification this water carries with it a substantial diapycnal flux of dissolved inorganic carbon (DIC). For AAIW, principal formatin processes include buoyancy forcing and mixing, with these serving to lighten CDW. An additional important formation pathway of AAIW is through the effect of interior processing (mixing, including cabelling) that serve to densify SAMW.A quantitative evaluation of the contribution of mixing, biology and gas exchange to the DIC evolution per water mass reveals that mixing and, secondarily, gas exchange, effectively nearly balance biology on annual scales (while the latter process can be dominant at seasonal scale). The distribution of DIC in the northward flowing water at 30 • S is thus primarily set by the DIC values of the water masses that are involved in the formation processes.

show abstract

Section: Marinovsupporting

confidence: 94%

Water masses as a unifying framework for understanding the Southern Ocean Carbon Cycle

et al. 2011

View full text Add to dashboard Cite

show abstract

“…The flow turns westward at approximately 25°S. This northward flow resembles the export path of AAIW described by Iudicone et al (2007), in which AAIW is injected in the subtropical gyre east of 90°W.…”

Section: Routesupporting

confidence: 57%

Subantarctic mode water: distribution and circulation

Herráiz‐Borreguero

Rintoul

2010

Ocean Dynamics

View full text Add to dashboard Cite

The subduction and export of subantarctic mode water (SAMW) as part of the overturning circulation play an important role in global heat, freshwater, carbon and nutrient budgets. Here, the spatial distribution and export of SAMW is investigated using Argo profiles and a climatology. SAMW is identified by a dynamical tracer: a minimum in potential vorticity. We have found that SAMW consists of several modes with distinct properties in each oceanic basin. This conflicts with the previous view of SAMW as a continuous water mass that gradually cools and freshens to the east. The circulation paths of SAMW were determined using (modified) Montgomery streamlines on the density surfaces corresponding with potential vorticity minima. The distribution of the potential vorticity minima revealed "hotspots" where the different SAMW modes subduct north of the Subantarctic Front. The subducted SAMWs follow narrow export pathways into the subtropical gyres influenced by topography. The export of warmer, saltier modes in these "hotspots" contributes to the circumpolar evolution of mode water properties toward cooler, fresher and denser modes in the east.

show abstract

“…The first is a deep overturning circulation that occurs as part of the global scale meridional overturning circulation (MOC) where water enters the Pacific basin below 3000-4000 m, upwells in the interior, and returns in the depth range of 1000-2000 m (Kuhlbrodt et al, 2007). The second, shallower circulation system consists of intermediate and subpolar mode waters (Yasuda, 1997;Talley, 2003;Iudicone et al, 2007) overlain by the main thermocline and wind-driven circulation cells.…”

Section: C) the Deep Noble Gas Distributionsmentioning

confidence: 99%

The deep distributions of helium isotopes, radiocarbon, and noble gases along the U.S. GEOTRACES East Pacific Zonal Transect (GP16)

et al. 2018

View full text Add to dashboard Cite

We report the deep distributions of noble gases, helium isotopes, and radiocarbon measured during the U.S. GEOTRACES GP16 East Pacific Zonal Transect between 152 and 77°W at 12-15°S in the South Pacific. The dominant feature is an intense tongue of hydrothermal effluent that extends more than 4,000 km westward from the East Pacific Rise (EPR) at ~2500m depth. The patterns reveal significant "downstream" variations in water mass structure, advection, and mixing that belie the simple perception of a continuous plume extending westward from the EPR. For example, one feature observed at 120°W, 14°S has tracer signatures that are consistent with a water mass originating from an area as much as 2,000 km south of this section, suggesting a quasi-permanent northward flow on the western flank of the EPR. Helium isotope variations in the plume show a uniquely high In the western end of the section, incoming bottom waters have relatively less hydrothermal hydrothermal helium, more radiocarbon, and more oxygen, as well as negative saturation anomalies for the heavy noble gases (Ar, Kr, and Xe). During the basin-scale upwelling of this water, diapycnal mixing serves to erase these negative anomalies. The relative magnitudes of the increases for the heavy noble gases (Ar, Kr, and Xe) are quantitatively consistent with this process. This leads us to estimate the relatively smaller effects on He and Ne saturations, which range from near zero to 0.2% and 0.3% respectively. With this information, we are able to refine our estimates of the magnitude of He ratio of non-atmospheric helium introduced into deep Pacific waters.pg. 2

show abstract

An Exchange Window for the Injection of Antarctic Intermediate Water into the South Pacific

Cited by 37 publications

References 60 publications

Water masses as a unifying framework for understanding the Southern Ocean Carbon Cycle

Water masses as a unifying framework for understanding the Southern Ocean Carbon Cycle

Subantarctic mode water: distribution and circulation

The deep distributions of helium isotopes, radiocarbon, and noble gases along the U.S. GEOTRACES East Pacific Zonal Transect (GP16)

Contact Info

Product

Resources

About