Cite this paper:
LIU Hongwei, ZHANG Qilong, PANG Chongguang, DUAN Yongliang, XU Jianping. The seasonal variation of the North Pacific Meridional Overturning Circulation heat transport[J]. HaiyangYuHuZhao, 2019, 37(2): 423-433

The seasonal variation of the North Pacific Meridional Overturning Circulation heat transport

LIU Hongwei1,2,5, ZHANG Qilong1,5, PANG Chongguang1,5, DUAN Yongliang3,4, XU Jianping2
1 Key Laboratory of Ocean Circulation and Waves, Institute of Oceanology, Chinese Academy of Sciences and Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China;
2 State Key Laboratory of Satellite Ocean Environment Dynamics, MNR, Hangzhou 310012, China;
3 Center for Ocean and Climate Research, First Institute of Oceanography, MNR, Qingdao 266061, China;
4 Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China;
5 Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
Abstract:
Based on the 50-year Simple Ocean Data Assimilation (SODA) reanalysis data, we investigated the basic characteristics and seasonal changes of the meridional heat transport carried by the North Pacific Meridional Overturning Circulation. And we also examined the dynamical and thermodynamic mechanisms responsible for these heat transport variability at the seasonal time scale. Among four cells, the tropical cell (TC) is strongest with a northward heat transport (NHT) of (1.75±0.30) PW (1 PW=1.0×1015 W) and a southward heat transport (SHT) of (-1.69±0.55) PW, the subtropical cell (STC) is second with a NHT of (0.71±0.65) PW and SHT of (-0.63±0.53) PW, the deep tropical cell (DTC) is third with a NHT of (0.18±0.03) PW and SHT of (-0.18±0.11) PW, while the subpolar cell (SPC) is weakest with a NHT of (0.09±0.05) PW and SHT of (-0.07±0.09) PW. These four cells all have different seasonal changes in their NHT and SHT. Of all, the TC has stronger change in its SHT than in its NHT, so do both the DTC and SPC, but the seasonal change in the STC SHT is weaker than that in its NHT. Therefore, their dynamical and thermodynamic mechanisms are different each other. The local zonal wind stress and net surface heat flux are mainly responsible for the seasonal changes in the TC and STC NHTs and SPC SHT, while the local thermocline circulations and sea temperature are primarily responsible for the seasonal changes of the TC, STC and DTC SHTs and SPC NHT.
Key words:    meridional overturning circulation|heat transport|North Pacific|seasonal variation   
Received: 2018-02-02   Revised: 2018-04-04
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Articles by LIU Hongwei
Articles by ZHANG Qilong
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References:
Bryan K. 1991. Poleward heat transport in the ocean:A review of a hierarchy of models of increasing resolution. Tellus A:Dynamic Meteorology and Oceanography, 43(4):104-115.
Bryden H L, Roemmich D H, Church J A. 1991. Ocean heat transport across 24°N in the Pacific. Deep Sea Research Part A. Oceanographic Research Papers, 38(3):297-324.
Carton J A, Giese B S. 2008. A reanalysis of ocean climate using Simple Ocean Data Assimilation (SODA). Monthly Weather Review, 136(8):2 999-3 017.
Fang G H, Wei Z X, Choi B H, Wang K, Fang Y, Li W. 2003. Interbasin freshwater, heat and salt transport through the boundaries of the East and South China Seas from a variable-grid global ocean circulation model. Science in China Series D:Earth Sciences, 46(2):149-161.
Fillenbaum E R, Lee T L, Johns W E, Zantopo R J. 1997. Meridional heat transport variability at 26.5°N in the North Atlantic. Journal of Physical Oceanography, 27(1):153-174, https://doi.org/10.1175/1520-0485(1997)027<0153:MHTVAN>2.0.CO;2.
Gu D F, Philander S G H. 1997. Interdecadal climate fluctuations that depend on exchanges between the tropics and extratropics. Science, 275(5301):805-807.
Hsiung J. 1985. Estimates of global oceanic meridional heattransport. Journal of Physical Oceanography, 15(11):1 405-1 413.
Johns W E, Baringer M O, Beal L M, Cunningham S A, Kanzow T, Bryden H L, Hirschi J J M, Marotzke J, Meinen C S, Shaw B, Curry R. 2011. Continuous, arraybased estimates of atlantic ocean heat transport at 26.5°N.Journal of Climate, 24(10):2 429-2 449.
Kleeman R, McCreary J P, Klinger B A. 1999. A mechanism for generating ENSO decadal variability. Geophysical Research Letters, 26(12):1 743-1 746.
Klinger B A, Marotzke J. 2000. Meridional heat transport by the subtropical cell. Journal of Physical Oceanography, 30(4):696-705.
Li P, Zhang Q L, Liu H W, Xu J P. 2011. Seasonal variation of the North Pacific meridional net heat transport. Advances in Marine Science, 29(3):275-284. (in Chinese with English abstract)
Liu H W, Zhang Q L, Duan Y L, Hou Y J. 2011. The threedimensional structure and seasonal variation of the North Pacific meridional overturning circulation. Acta Oceanologica Sinica, 30(3):33-42.
Liu Z Y, Philander S G H, Pacanowski R C. 1994. A GCM study of tropical-subtropical upper-ocean water exchange.Journal of Physical Oceanography, 24(12):2 606-2 623.
Lu P, Mccreary J P, Klinger B A. 1998. Meridional circulation cells and the source waters of the Pacific equatorial undercurrent. Journal of Physical Oceanography, 28(1):62-84.
McCreary J P, Lu P. 1994. Interaction between the subtropical and equatorial ocean circulations:the subtropical cell.Journal of Physical Oceanography, 24(2):466-497.
McCreary J P, Yu Z J. 1992. Equatorial dynamics in a 212-layer model. Progress in Oceanography, 29(1):61-132.
McPhaden M J, Zhang D X. 2002. Slowdown of the meridional overturning circulation in the upper Pacific Ocean.Nature, 415(6872):603-608.
Nonaka M, Xie S P, McCreary J P. 2002. Decadal variations in the subtropical cells and equatorial pacific SST.Geophysical Research Letters, 29(7):20-1-20-4, https://doi.org/10.1029/2001GL013717.
Pedlosky J. 1987. An inertial theory of the equatorial undercurrent. Journal of Physical Oceanography, 17(11):1 978-1 985.
Riccardo F, Molteni F, Kucharski F. 2014. Pacific interdecadal variability driven by tropical-extratropical interactions.Climate Dynamics, 42(11-12):3 337-3 355.
Rothstein L M, Zhang R H, Busalacchi A J, Chen D K. 1998. A numerical simulation of the mean water Pathways in the subtropical and tropical Pacific Ocean. Journal of Physical Oceanography, 28(2):322-343.
Schott F A, Stramma L, Wang W Q, Giese B S, Zantopp R. 2008. Pacific subtropical cell variability in the SODA 2.0.2/3 assimilation. Geophysical Research Letters, 35(10):L10607, https://doi.org/10.1029/2008GL033757.
Song W, Lan J, Liu Q Y, Sui D D, Zeng L L, Wang D X. 2014. Decadal variability of heat content in the South China Sea inferred from observation data and an ocean data assimilation product. Ocean Science, 10(1):135-139.
Trenberth K E, Solomon A. 1994. The global heat-balance:heat transports in the atmosphere and ocean. Climate Dynamics, 10(3):107-134, https://doi.org/10.1007/BF00210625.
Wang J D, Carton J A. 2002. Seasonal heat budgets of the north Pacific and north Atlantic Oceans. Journal of Physical Oceanography, 32(12):3 474-3 489.
Wang Q, Huang R X. 2005. Decadal variability of pycnocline flows from the subtropical to the Equatorial Pacific.Journal of Physical Oceanography, 35(10):1 861-1 875.
Zhang L P, Wu L X, Yu L S. 2011. Oceanic origin of a recent La Niña-like trend in the Tropical Pacific. Advances in Atmospheric Sciences, 28(5):1 109-1 117.
Zhang Q L, Hou Y J, Yan T Z. 2012. Inter-annual and interdecadal variability of Kuroshio heat transport in the East China Sea. International journal of Climatology, 32(4):481-488.
Zhang Q, Yang H J, Zhong Y F, Wang D X. 2005. An idealized study of the impact of extratropical climate change on El Niño-Southern Oscillation. Climate Dynamics, 25(7-8):869-880.