The Global Subduction/Obduction Rates: Their Interannual and Decadal Variability

• Published in: Journal of Climate
• Main Authors: Liu, Ling Ling, Huang, Rui Xin, Liu, LL (reprint author), Chinese Acad Sci, Inst Oceanol, Key Lab Ocean Circulat & Waves, Qingdao 266071, Peoples R China.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2012
• Subjects: Water Mass Formation; North-atlantic Ocean; Subtropical Mode Water; Ideal-fluid Thermocline; Wind-driven Circulation; Southwest Pacific-ocean; Hydrographic Section; Indian-ocean; Sea; Layer; Meteorology & Atmospheric Sciences; Indian; Pacific; Southern Ocean; North Atlantic
• Online Access: http://ir.qdio.ac.cn/handle/337002/12195; https://doi.org/10.1175/2011JCLI4228.1

Ventilation, including subduction and obduction, for the global oceans was examined using Simple Ocean Data Assimilation (SODA) outputs. The global subduction rate averaged over the period from 1959 to 2006 is estimated at 505.8 Sv (1 Sv = 10(6) m(3) s(-1)), while the corresponding global obduction rate is estimated at 482.1 Sv. The annual subduction/obduction rates vary greatly on the interannual and decadal time scales. The global subduction rate is estimated to have increased 7.6% over the past 50 years, while the obduction rate is estimated to have increased 9.8%. Such trends may be insignificant because errors associated with the data generated by ocean data assimilation could be as large as 10%. However, a major physical mechanism that induced these trends is primarily linked to changes in the Southern Ocean. While the Southern Ocean plays a key role in global subduction and obduction rates and their variability, both the Southern Ocean and equatorial regions are critically important sites of water mass formation/erosion.