A Pulsation Mode in the Antarctic Circumpolar Current South of Australia

Sun, Che; Watts, D. Randolph
May 2002
Journal of Physical Oceanography;May2002, Vol. 32 Issue 5, p1479
Academic Journal
A streamfunction EOF method is developed to identify long-term thermohaline variations within a strong baroclinic current. The temporal variability associated with meandering fronts and mesoscale eddies is removed by projecting hydrographic data into a baroclinic streamfunction space. The residual field, after removing the streamfunction mean field, is analyzed to find empirical orthogonal functions. The method is applied to a time series of hydrographic sections across the Antarctic Circumpolar Current (ACC) south of Australia. The temperature variation in the surface layer (0–300 dbar) is dominated by a seasonal signal. In the subsurface water (300–3000 dbar), a separately calculated first EOF mode dominates the thermohaline variation and exhibits two phases. In the strengthening phase both salinity and temperature in the Subantarctic Mode Water increase and the ACC section is characterized by less Antarctic Intermediate Water and higher salinity at the core of the Circumpolar Deep Water. The water masses vary conversely in the relaxing phase. The authors call this mode the ACC pulsation mode and hypothesize that it is related to the ACC barotropic transport and is a response to the large-scale wind stress variation. Observations of westerly winds and ACC transport appear to support the hypothesis as they all display semiannual periods nearly in phase with higher coherence to the south.


Related Articles

  • Oceanic Boundary Conditions for Jakobshavn Glacier. Part II: Provenance and Sources of Variability of Disko Bay and Ilulissat Icefjord Waters, 1990-2011*. Gladish, Carl V.; Holland, David M.; Lee, Craig M. // Journal of Physical Oceanography;Jan2015, Vol. 45 Issue 1, p33 

    Jakobshavn Glacier, west Greenland, has responded to temperature changes in Ilulissat Icefjord, into which it terminates. Basin waters in this fjord exchange with neighboring Disko Bay waters of a particular density at least once per year. This study determined the provenance of this isopycnic...

  • Oceanic Boundary Conditions for Jakobshavn Glacier. Part I: Variability and Renewal of Ilulissat Icefjord Waters, 2001-14*. Gladish, Carl V.; Holland, David M.; Rosing-Asvid, Aqqalu; Behrens, Jane W.; Boje, Jesper // Journal of Physical Oceanography;Jan2015, Vol. 45 Issue 1, p3 

    Jakobshavn Glacier, west Greenland, has responded to temperature changes in Ilulissat Icefjord, into which it terminates. This study collected hydrographic observations inside Ilulissat Icefjord and from adjacent Disko Bay between 2001 and 2014. The warmest deep Disko Bay waters were blocked by...

  • Changes in Temperature and Salinity Tendencies of the Upper Subtropical North Atlantic Ocean at 24.5°°N. Véélez-Belchíí, Pedro; Hernáández-Guerra, Alonso; Fraile-Nuez, Eugenio; Beníítez-Barrios, Veróónica // Journal of Physical Oceanography;Nov2010, Vol. 40 Issue 11, p2546 

    Strong interest in multidecadal changes in ocean temperature and heat transport has resulted in the occupation of the North Atlantic Ocean hydrographic transect along 24.5°°N five times since 1957, more than any other transoceanic section in the world. This latitude is chosen because it is...

  • Circulation and Modification of Warm Deep Water on the Central Amundsen Shelf. Ha, H. K.; Wåhlin, A. K.; Kim, T. W.; Lee, S. H.; Lee, J. H.; Lee, H. J.; Hong, C. S.; Arneborg, L.; Björk, G.; Kalén, O. // Journal of Physical Oceanography;May2014, Vol. 44 Issue 5, p1493 

    The circulation pathways and subsurface cooling and freshening of warm deep water on the central Amundsen Sea shelf are deduced from hydrographic transects and four subsurface moorings. The Amundsen Sea continental shelf is intersected by the Dotson trough (DT), leading from the outer shelf to...

  • Relationship between oceanic heat content and sea surface height on interannual time scale. Zhang, Linlin; Sun, Che; Hu, Dunxin // Chinese Journal of Oceanology & Limnology;Nov2012, Vol. 30 Issue 6, p1026 

    The relationship between heat content and sea surface height (SSH) in the global ocean on the interannual time scale is examined with satellite altimeter measurements, historical hydrography, and model assimilation outputs. Results show that correlation between altimetric SSH and heat content in...

  • Mechanisms Governing Interannual Variability of Upper-Ocean Temperature in a Global Ocean Hindcast Simulation. Doney, Scott C.; Yeager, Steve; Danabasoglu, Gokhan; Large, William G.; McWilliams, James C. // Journal of Physical Oceanography;Jul2007, Vol. 37 Issue 7, p1918 

    The interannual variability in upper-ocean (0–400 m) temperature and governing mechanisms for the period 1968–97 are quantified from a global ocean hindcast simulation driven by atmospheric reanalysis and satellite data products. The unconstrained simulation exhibits considerable...

  • Hydrographical characteristics and oxygen isotopic signatures of water in a coastal environment (Mangalore) along the southeastern Arabian Sea. Jacob, Josia; Ghosh, Prosenjit; Dineshbabu, A.; Sabu, P.; Srinivas, K.; Sulochanan, Bindu // Journal of Oceanography;Jun2014, Vol. 70 Issue 3, p251 

    Coastal marine environments are important links between the continents and the open ocean. The coast off Mangalore forms part of the upwelling zone along the southeastern Arabian Sea. The temperature, salinity, density, dissolved oxygen and stable oxygen isotope ratio (δO) of surface waters...

  • Historical Ocean Subsurface Temperature Analysis with Error Estimates. Ishii, Masayoshi; Kimoto, Masahide; Kachi, Misako // Monthly Weather Review;Jan2003, Vol. 131 Issue 1, p51 

    An objective analysis of monthly ocean subsurface temperatures from 1950 to 1998 is carried out. The analysis scheme and the results with estimated analysis errors are presented. The analysis domain is global with a horizontal grid of 1° × 1° and 14 vertical levels in the upper 500 m....

  • Estimating Sea Surface Temperature from Infrared Satellite and In Situ Temperature Data. Emery, W. J.; Castro, Sandra; Wick, G. A.; Schluessel, Peter; Donlon, Craig // Bulletin of the American Meteorological Society;Dec2001, Vol. 82 Issue 12, p2773 

    Sea surface temperature (SST) is a critical quantity in the study of both the ocean and the atmosphere as it is directly related to and often dictates the exchanges of heat, momentum, and gases between the ocean and the atmosphere. As the most widely observed variable in oceanography, SST is...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics