The Effects of Indian Ocean Dipole

 

 

 

 

Eastern Indian Ocean

 

·       Drought at the eastern Indian Ocean

o       Could possibly cause more forest fires that lead to serious haze event.

o       Nutrients in smoke from the 1997 Indonesian wildfires produced a large algae bloom. (http://www.redtidealert.com/TheFireTheory.html)

o       Shortage of water supply that will affect the economic activities and daily life.

 

·       Upwelling and large phytoplankton bloom at the western Sumatra to southern Java

o       Death of nearly all coral and fish in a 400 km stretch of the Mentawai Islands reef, southwest of Sumatra in Indonesia, in 1997. (http://www.redtidealert.com/TheFireTheory.html)

o       The coastal marine environment that being affected by 2004 tsunami could face serious threat again during IOD.

 

·       Lowering of Sea Surface Height

o       Bleaching of coral at Phuket, Thailand (http://www.springerlink.com/openurl.asp?genre=article&issn=0025-3162&volume=141&issue=1&spage=21 )

 

 

Western Indian Ocean

 

·       Heavy rainfall

o       Unusually heavy rainfall and flood over Kenya, Somalia and Ethiopia (http://www.nature.com/nature/journal/v401/n6751/full/401337a0_fs.html).

o       Almost 2 m — rise in the level of Lake Victoria. (http://www.agu.org/pubs/crossref/1999/1999GL900165.shtml)

o       From late October 1997 through January 1998, torrential rains occurred in most of East Africa, resulting in the worst flooding in the region since 1961 and rainfall that was 60-100 times the seasonal average (http://www.cdc.gov/mmwr/preview/mmwrhtml/00051976.htm)

o       The floods have also caused extensive damage to crops, both in the field and in stores, as well as losses of large numbers of livestock. Severe damage has also been inflicted on the sub-region’s infrastructure (roads, bridges, rail lines), seriously disrupting the movement of goods within and between countries. In some countries such as Somalia and Kenya loss of human life has been significant. Food assistance is currently being provided to the affected people in these countries but substantial assistance is still urgently needed not only in the form of food but also as logistical support in view of transport difficulties. In the sub-region as a whole some 10 million people currently require emergency assistance. (http://www.fao.org/documents/show_cdr.asp?url_file=/DOCREP/004/W7832E/W7832E00.HTM)

 

·       Disease outbreak

o       Acute Rift Valley fever virus (RVFV) outbreak 1997-98. Estimate approximately 27,500 infections occurred, making this the largest recorded outbreak of RVFV in East Africa.  (http://www.cdc.gov/ncidod/EID/vol8no2/01-0023.htm)

o       Rift Valley fever (RVF) is an arthropod-borne (primarily mosquito), acute, febrile, viral disease of sheep, cattle, and goats. The disease in these species is characterized by high abortion rates, high mortality in neonates, and hepatic necrosis. (http://www.vet.uga.edu/VPP/gray_book/FAD/rvf.htm)

o       The outbreaks have generally occurred in otherwise dry areas following periods of heavy rainfall. (http://www.vet.uga.edu/VPP/gray_book/FAD/rvf.htm)

 

 

India, Bangladesh and Vietnam

·       Excess rainfall (http://www.deccanherald.com/deccanherald/mar112004/snt2.asp)

 

 

Eastern Asia

·       Hot and dry summer (http://www.deccanherald.com/deccanherald/mar112004/snt2.asp)

 

 

Australia

·       Dry winter at southwestern Australia (http://www.deccanherald.com/deccanherald/mar112004/snt2.asp)

 

 

 

 

 

References

 

Nerilie J. Abram, Michael K. Gagan, Malcolm T. McCulloch, John Chappell, and Wahyoe S. Hantoro (2003).  Coral Reef Death During the 1997 Indian Ocean Dipole Linked to Indonesian Wildfires. Science, Vol. 301 (5635), 952 – 955, DOI: 10.1126/science.1083841. (http://www.sciencemag.org/cgi/content/full/sci;301/5635/952)

 

Letters: The Sudden Death of a Coral Reef ,Bert W. Hoeksema, Daniel F. R. Cleary;, N. J. Abram, M. K. Gagan, M. T. McCulloch, J. Chappell, and W. S. Hantoro
Science 27 February 2004: 1293-1294  (http://www.sciencemag.org/cgi/content/full/sci;303/5662/1293b)

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Technical Comments: Response to Comment on "Coral Reef Death During the 1997 Indian Ocean Dipole Linked to Indonesian Wildfires", Nerilie J. Abram, Michael G. Gagan, Malcolm T. McCulloch, John Chappell, and Wahyoe S. Hantoro, Science 27 February 2004: 1297. (http://www.sciencemag.org/cgi/content/full/sci;303/5662/1297b)

 

B. Brown, K. Clarke, and R. Warwick (2002). Serial patterns of biodiversity change in corals across shallow reef flats in Ko Phuket, Thailand, due to the effects of local (sedimentation) and regional (climatic) perturbations. Marine Biology, Vol. 141(1), 21-29, DOI: 10.1007/s00227-002-0810-0. (http://www.springerlink.com/openurl.asp?genre=article&issn=0025-3162&volume=141&issue=1&spage=21 )

 

H. H. Saji, B. N. Goswami, P. H. Vinayachandran, T. Yamagata, (1999). A dipole mode in the tropical Indian Ocean. Nature, 401, 360.  (http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v401/n6751/full/401360a0_fs.html)

 

Webster, P. J., Moore, A. M., Loschnigg, J. P. & Leben, R.R. (1999). Coupled ocean–atmosphere dynamics in the Indian Ocean during 1997–98. Nature, 401, 356-360 (http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v401/n6751/full/401356a0_fs.html).

 

David Anderson (1999). Climatology: Extremes in the Indian Ocean. Nature, 401, 337 – 338, doi:10.1038/43807. (http://www.nature.com/nature/journal/v401/n6751/full/401337a0_fs.html)

 

Birkett, C., Murtugudde, R. & Allan, T. (1999). Indian Ocean climate event brings floods to East Africa’s lakes and the Sudd marsh. Geophys. Res. Lett., 26, 1031-1034.  (http://www.agu.org/pubs/crossref/1999/1999GL900165.shtml)