The thermodynamic balance of the Weddell Gyre

نویسندگان

  • Alberto C. Naveira Garabato
  • Jan D. Zika
  • Loïc Jullion
  • Peter J. Brown
  • Paul R. Holland
  • Michael P. Meredith
  • Sheldon Bacon
چکیده

The thermodynamic balance of the Weddell Gyre is assessed from an inverse estimate of the circulation across the gyre’s rim. The gyre experiences a weak net buoyancy gain that arises from a leading-order cancelation between two opposing contributions, linked to two cells of water mass transformation and diapycnal overturning. The lower cell involves a cooling-driven densification of 8.4± 2.0 Sv of Circumpolar Deep Water and Antarctic Bottom Water near the gyre’s southern and western margins. The upper cell entails a freshening-driven conversion of 4.9 ± 2.0 Sv of Circumpolar Deep Water into lighter upper ocean waters within the gyre interior. The distinct role of salinity between the two cells stems from opposing salinity changes induced by sea ice production, meteoric sources, and admixture of fresh upper ocean waters in the lower cell, which contrasts with coherent reductions in salinity associated with sea ice melting and meteoric sources in the upper cell.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Freshwater fluxes in the Weddell Gyre: results from δ18O.

Full-depth measurements of δ(18)O from 2008 to 2010 enclosing the Weddell Gyre in the Southern Ocean are used to investigate the regional freshwater budget. Using complementary salinity, nutrients and oxygen data, a four-component mass balance was applied to quantify the relative contributions of meteoric water (precipitation/glacial input), sea-ice melt and saline (oceanic) sources. Combinatio...

متن کامل

Thermohaline stratification below the Southern Ocean sea ice

The end of winter stratification within the cold cyclonic trough of the Weddell gyre near 60øS between 5øE and the Greenwich meridian is resolved with the Mikhail Somov data set. The temperature maximum of the Weddell Deep Water (WDW) is, for the most part, less than 0.5øC, but warmer cells of WDW are found. These warm WDW cells have temperature, salinity, and oxygen properties similar to the W...

متن کامل

On the export of Antarctic Bottom Water from the Weddell Sea

A survey of the current field over the South Scotia Ridge, obtained with a lowered Acoustic Doppler Current Profiler (LADCP), is presented. There is a pattern of northward (southward) flow on the western (eastern) side of each of four deep passages in the ridge, which is supported by tracer measurements. The net full-depth LADCP-referenced geostrophic transport over the ridge is 2277 Sv (1 Sv=1...

متن کامل

Martinson and Iannuzzi: Weddell Gyre and Global Climate

We examine the spatiotemporal variability of the upper ocean-sea ice system of the Atlantic sector of the Southern Ocean subpolar seas (Weddell gyre), and the nature of its covariability with extrapolar climate, identifying teleconnections and their mechanisms. To systematically evaluate the sporadic and sparse distribution of subpolar data we employed an optimal analysis involving Empirical Or...

متن کامل

An Idealized Model of Weddell Gyre Export Variability

Recent observations suggest that the export of Antarctic Bottom Water (AABW) from the Weddell Sea has a seasonal cycle in its temperature and salinity that is correlated with annual wind stress variations. This variability has been attributed to annual vertical excursions of the isopycnals in theWeddell Gyre, modifying the water properties at the depth of the Orkney Passage. Recent studies attr...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2015