Indian Ocean Gyre

The Indian Ocean gyre, located in the Indian Ocean, is one of the five major oceanic gyres, large systems of rotating ocean currents, which together form the backbone of the global conveyor belt. The Indian Ocean gyre is composed of two major currents: the South Equatorial Current, and the West Australian Current.

The Indian Ocean gyre

Normally moving counter-clockwise, in the winter the Indian Ocean gyre reverses direction due to the seasonal winds of the South Asian Monsoon. In the summer, the land is warmer than the ocean, so surface winds blow from the ocean to the land. However, during the winter, these temperatures reverse, making the winds blow from the land to the ocean. Because most of the air pressure gradient is retained behind the Tibetan plateau, air pressure gradients over the Indian Ocean and the gyre are small. This results in winds of moderate strength, due to the protection from the full force winds blowing off the Mongolian high pressure region. Because of these moderate, dry winds, the Winter Monsoon season in the Indian Ocean region is the dry season for most of Southern Asia. Due to this seasonal wind cycle, the currents of the Indian Ocean, which make up the Indian Ocean gyre, are directly affected, causing reversal.[1]

Garbage patch
This section is an excerpt from Indian Ocean garbage patch.[edit]
Map showing 5 circles. The first is between western Australia and eastern Africa. The second is between eastern Australia and western South America. The third is between Japan and western North America. Of the two in the Atlantic, one is in hemisphere.
North Atlantic
gyre
North Atlantic
gyre
North Atlantic
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Indian
Ocean
gyre
North
Pacific
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South
Pacific
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South Atlantic
        gyre
Map showing 5 circles. The first is between western Australia and eastern Africa. The second is between eastern Australia and western South America. The third is between Japan and western North America. Of the two in the Atlantic, one is in hemisphere.
There are trash vortices in each of the five major oceanic gyres
Map of gyres centered near the south pole (click to enlarge)
The Indian Ocean Garbage Patch on a continuous ocean map centered near the south pole
The Indian Ocean garbage patch, discovered in 2010, is a marine garbage patch, a gyre of marine litter, suspended in the upper water column of the central Indian Ocean, specifically the Indian Ocean Gyre, one of the five major oceanic gyres.[2][3][4][5][6][7] The patch does not appear as a continuous debris field. As with other patches in each of the five oceanic gyres, the plastics in it break down to ever smaller particles, and to constituent polymers.[8] As with the other patches, the field constitutes an elevated level of pelagic plastics, chemical sludge, and other debris; primarily particles that are invisible to the naked eye. The concentration of particle debris has been estimated to be approximately 10,000 particles per square kilometer.[9][10][11][12]

References
  1. Tomczak, Matthias & J. Stuart Godfrey: Regional Oceanography: and Introduction 2nd Edition. (2003). ISBN 8170353068
  2. "Ocean Geography ~ MarineBio Conservation Society". www.marinebio.org. 17 June 2018. Retrieved 2021-09-17.
  3. First Voyage to South Atlantic Pollution Site SustainableBusiness.com News access-date=10 December 2021
  4. New garbage patch discovered in Indian Ocean Archived 2 October 2011 at the Wayback Machine, Lori Bongiorno, Green Yahoo, 27 July 2010
  5. Opinion: Islands are 'natural nets' for plastic-choked seas Archived 6 October 2012 at the Wayback Machine Marcus Eriksen for CNN, Petroleum, CNN Tech 24 June 2010
  6. Our Ocean Backyard: Exploring plastic seas Archived 20 June 2010 at the Wayback Machine, Dan Haifley, 15 May 2010, Santa Cruz Sentinel
  7. Life aquatic choked by plastic 14 November 2010, Times Live
  8. Moore, Charles (November 2003). "Across the Pacific Ocean, plastics, plastics, everywhere". Natural History Magazine. Archived from the original on 2009-07-06.
  9. Sesini, Marzia (August 2011). "The Garbage Patch In The Oceans: The Problem And Possible Solutions" (PDF). Columbia University.
  10. For a discussion of the current sampling techniques and particle size, see Peter Ryan, Charles Moore et al., Monitoring the abundance of plastic debris in the marine environment. Phil. Trans. R. Soc. B 27 July 2009 vol. 364 no. 1526 1999–2012, doi:10.1098/rstb.2008.0207
  11. "OSU: Reports of giant ocean 'garbage patch' are exaggerated". 4 January 2011. Archived from the original on 14 February 2011. Retrieved 7 January 2011.
  12. Transoceanic Trash: International and United States Strategies for the Great Pacific Garbage Patch, Susan L. Dautel, 3 Golden Gate U. Envtl. L.J. 181 (2009)


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