Bottom water has warmed by about 0.005 to 0.01 degrees Celsius since the early 1990s, according to the Institute of Observational Research for Global Change (IORGC) of the Japan Agency for Marine-Earth Science and Technology. The institute conducted trans-Pacific hydrographic observations along the pathway of Lower Circumpolar Deep Water from its research vessel, the Mirai, between 1999 and 2005 and compared the results to those of prior to the early 1990s.

The research findings were reported on January 4, 2007, and published in Geophysical Research Letters Vol. 33: http://www.agu.org/journals/gl/

According to the report, this bottom water warming was equivalent to warmth that could raise atmospheric temperature above the hydrographic lines of the research from 1 to 1.6 degrees Celsius.

Ocean circulation is a dominant factor in global climate, as it conveys large amounts of heat and carbon dioxide. Some numerical model simulations have estimated that bottom water temperature from the South to the North Pacific Ocean would rise over several decades, as bottom water formation around the Antarctica decreases. The data reported by the IORGC supports the predictions of these models.

http://www.jamstec.go.jp/iorgc/eng/index.html
http://www.agu.org/pubs/crossref/2006.../2006GL027933.shtml

Posted: 2007/04/07 05:56:53 PM
Japanese version

TAG Ecosystem , Government , University/Research institute