姚文峻,史久新

• 1:中国海洋大学物理海洋实验室

摘要(Abstract)：

通过分析1981—2010年的SODA2.2.4(Simple Ocean Data Assimilation)温盐数据,发现南极中层水在这个时期表现出了盐度减小的变化趋势,包括垂向盐度极小值处与沿27.2kg/m~3等密度面的盐度。但是这个淡化过程并不是渐进的,而是先在1996—2000年间达到了一个盐度异常的最大值,然后才进入快速减小阶段。盐度最小值处(27.2kg/m~3等密度面)盐度的EOF分解表明,南非以南海域以及东南大西洋海域的盐度减小幅度显著大于太平洋与印度洋水体,这隐含了厄加勒斯流系统对大西洋-印度洋通道上中层水体性质变化的重要影响。在形成机制上,本文从两个海气相互作用过程解释了上述的结果。南半球纬向风应力的EOF结果表明,亚南极锋以南的西风带在1979—2014年间是一个增强的变化趋势,由此产生的低盐南极表层水向北输送导致了上述的多年南极中层水淡化现象。这其中1998年风应力的极大值应当对应一个盐度异常的极小值,但在这里表现出的是盐度异常的最大值产生了一个矛盾的因果关系。进一步的分析表明,这个盐度异常最大值是海表面淡水输入量(降雨-蒸发)在相应时期大幅度减小的结果。

关键词(KeyWords)： 南极中层水;多年变化;西风;淡水输入

Abstract:

Keywords:

基金项目(Foundation): 南北极环境综合考察与评估专项“极地对全球和我国气候变化影响的综合评价(CHINARE-04-04)”;“南极环境综合分析与评价(CHINARE-04-01)”资助~~

作者(Author): 姚文峻,史久新

DOI: 10.16441/j.cnki.hdxb.20170026

参考文献(References)：

• [1]Piola A R and D T Georgi.Circumpolar properties of Antarctic intermediate water and Subantarctic Mode Water[J].Deep-Sea Res A,1982,29(6):687-711,doi:10.1016/0198-0149(82)90002-4.
• [2]Orsi A H,Whitworth T Iii and Nowlin Jr W D,On the meridional extent and fronts of the Antarctic Circumpolar Current[J].DeepSea Res I,1995,42(5):641-673,doi:http://dx.doi.org/10.1016/0967-0637(95)00021-W.
• [3]Whitworth T and Nowlin W D.Water masses and currents of the Southern Ocean at the Greenwich Meridian[J].J Geophys Res Oceans,1987,92(C6):6462-6476,doi:10.1029/JC092iC06p06462.
• [4]Talley L D.Descriptive Physical Oceanography:An Introduction[M].Boston:Academic Press,2011.
• [5]Talley L D.Antarctic Intermediate Water in the South Atlantic[M].//The South Atlantic:Present and Past Circulation.New York:Springer,1996.
• [6]Sloyan B M and Rintoul S R.Circulation,renewal and modification of Antarctic mode and intermediate water[J].J Phys Oceanogr,2001,31(4):1005-1030,doi:http://dx.doi.org/10.1175/1520-0485(2001)031<1005:CRAMOA>2.0.CO;2.
• [7]Speich S,Blanke B,de Vries P,et al.Tasman leakage:A new route in the global ocean conveyor belt[J].Geophys Res Lett,2002,29(10):1416,doi:10.1029/2001gl014586.
• [8]Ridgway K R and Dunn J R.Observational evidence for a Southern Hemisphere oceanic supergyre[J].Geophys Res Lett,2007,34,L13612,doi:10.1029/2007gl030392.
• [9]Las Heras M M and Schlitzer R.On the importance of intermediate water flows for the global ocean overturning[J].J Geophys Res Oceans,1999,104(C7):15515-15536,doi:10.1029/1999JC900102.
• [10]Donners J,and Drijfhout S S.The Lagrangian view of South Atlantic interocean exchange in a global ocean model compared with inverse model results[J].J Phys Oceanogr,2004,34(5):1019-1035,doi:http://dx.doi.org/10.1175/1520-0485(2004)034<1019:TLVOSA>2.0.CO;2.
• [11]Speich S,Blanke B and Cai W.Atlantic meridional overturning circulation and the Southern Hemisphere supergyre[J].Geophys Res Lett,2007,34,L23614,doi:10.1029/2007GL031583.
• [12]Talley L D.Closure of the global overturning circulation through the Indian,Pacific,and Southern Oceans:Schematics and transports[J].Oceanography,2013,26(1):80-97,doi:http://dx.doi.org/10.5670/oceanog.2013.07.
• [13]Davis R E.Intermediate-depth circulation of the Indian and South Pacific Oceans measured by autonomous floats[J].J Phys Oceanogr,2005,35(5):683-707,doi:http://dx.doi.org/10.1175/JPO2702.1.
• [14]Lavender K L,Owens W B and Davis R E.The mid-depth circulation of the subpolar North Atlantic Ocean as measured by subsurface floats[J].Deep-Sea Res I,2005,52(5):767-785,doi:10.1016/j.dsr.2004.12.007.
• [15]Bindoff N L and Mc Dougall T J.Decadal changes along an Indian Ocean section at 32Sand their interpretation[J].J Phys Oceanogr,2000,30(6):1207-1222,doi:http://dx.doi.org/10.1175/1520-0485(2000)030<1207:DCAAIO>2.0.CO;2.
• [16]Curry R,Dickson B and Yashayaev I.A change in the freshwater balance of the Atlantic Ocean over the past four decades[J].Nature,2003,426(6968):826-829,doi:10.1038/nature02206.
• [17]Wong A P,Bindoff N L and Church J A.Large-scale freshening of intermediate waters in the Pacific and Indian Oceans[J].Nature,1999,400(6743),440-443:doi:10.1038/22733.
• [18]Helm K P,Bindoff N L and Church J A.Changes in the global hydrological-cycle inferred from ocean salinity[J].Geophys Res Lett,2010,37,L18701,doi:10.1029/2010GL044222.
• [19]Durack P J,Wijffels S E.Fifty-year trends in global ocean salinities and their relationship to broad-scale warming[J].J Climate,2010,23(16):4342-4362,doi:10.1175/2010JCLI3377.1.
• [20]Church J A,Godfrey J S,Jackett D R,et al.A model of sea level rise caused by ocean thermal expansion[J].J Climate,1991,4(4):438-456,doi:http://dx.doi.org/10.1175/1520-0442(1991)004〈0438:AMOSLR〉2.0.CO;2.
• [21]Bindoff N L and Mcdougall T J.Diagnosing climate change and ocean ventilation using hydrographic data[J].J Phys Oceanogr,1994,24(6):1137-1152,doi:10.1175/1520-0485(1994)024〈1137:DCCAOV〉2.0.CO;2.
• [22]Held I M and Soden B J.Robust responses of the hydrological cycle to global warming[J].J Climate,2006,19(21):5686-5699,doi:http://dx.doi.org/10.1175/JCLI3990.1.
• [23]Skliris N,Marsh R,Josey S A,et al.Salinity changes in the world ocean since 1950in relation to changing surface freshwater fluxes[J].Climate Dynamics,2014,43(3-4):709-736,doi:10.1007/s00382-014-2131-7.
• [24]Santoso A and England M H.Antarctic intermediate water circulation and variability in a coupled climate model[J].J Phys Oceanogr,2004,34(10):2160-2179,doi:http://dx.doi.org/10.1175/1520-0485(2004)034<2160:AIWCAV>2.0.CO;2.
• [25]Naveira Garabato A C,Jullion L,Stevens D P,et al.Variability of subantarctic mode water and Antarctic Intermediate Water in the rake passage during the late-twentieth and early-twenty-first centuries[J].J Climate,2009,22(13):3661-3688,doi:10.1175/2009jcli2621.1.
• [26]Close S E,Naveira Garabato A C,McDonagh E L.et al.Control of mode and intermediate water mass properties in Drake Passage by the Amundsen Sea Low[J].J Climate,2013,26(14):5102-5123,doi:10.1175/JCLI-D-12-00346.1.
• [27]Sverdrup H U,Johnson M W and Fleming R H.The Oceans:Their Physics,Chemistry,and General Biology[M].New York:Prentice-Hall,1942.
• [28]Fetter A,Schodlok M and Zlotnicki V.Antarctic Intermediate Water Formation in a High-Resolution OGCM[R].Vienna:Vienna EGU General Assembly Conference Abstracts,2010.
• [29]Mc Cartney M S.The subtropical recirculation of mode waters[J].J Mar Res,1982,40:427-464
• [30]Schmidtko S and Johnson G C.Multidecadal warming and Shoaling of Antarctic Intermediate Water[J].J Climate,2012,25(1):207-221,doi:10.1175/jcli-d-11-00021.1.
• [31]Carton J A and Giese B S.A reanalysis of ocean climate using Simple Ocean Data Assimilation(SODA)[J].Monthly Weather Review,2008,136(8):2999-3017,doi:http://dx.doi.org/10.1175/2007MWR1978.1.
• [32]Yang X Y and He Z.Decadal change of Antarctic Intermediate Water in the region of Brazil and Malvinas confluence[J].DeepSea Res I,2014,88:1-7,doi:10.1016/j.dsr.2014.02.007.
• [33]Trenberth K E,Large W G and Olson J G.The effective drag coefficient for evaluating wind stress over the oceans[J].J Climate,1989,2(12):1507-1516,doi:http://dx.doi.org/10.1175/1520-0442(1989)002<1507:TEDCFE>2.0.CO;2.
• [34]Dong S,Sprintall J,Gille S T,et al.Southern Ocean mixed-layer depth from Argo float profiles[J].J Geophys Res,2008,113(C6),doi:10.1029/2006jc004051.
• [35]Sun C and Watts D R,A view of ACC fronts in streamfunction space[J].Deep-Sea Res I,2002,49(7):1141-1164,doi:10.1016/S0967-0637(02)00027-4.
• [36]Rimaud J,Speich S,Blanke B,et al.The exchange of Intermediate Water in the southeast Atlantic:Water mass transformations diagnosed from the Lagrangian analysis of a regional ocean model[J].J Geophys Res,2012,117(C8),doi:10.1029/2012jc008059.
• [37]Gordon A L,Weiss R,Smethie Jr W M,et al.Thermociine and intermediate water communication[J].J Geophys Res,1992,97(C5):7223-7240,doi:10.1029/92JC00485.
• [38]Mc Carthy G D,King B A,Cipollini P,et al.On the sub-decadal variability of South Atlantic Antarctic Intermediate Water[J].Geophys Res Lett,2012,39,L10605,doi:10.1029/2012GL051270.
• [39]Biastoch A,Durgadoo J V,Morrison A K,et al.Atlantic multidecadal oscillation covaries with Agulhas leakage[J].Nature Communications,2015,6,doi:10.1038/ncomms10082.
• [40]Reid J R.On the Circulation of the South Atlantic Ocean[M].//The South Atlantic.Berlin Heidelberg:Springer,1996:13-44.
• [41]Rintoul S R and England M H.Ekman transport dominates local air-sea fluxes in driving variability of Subantarctic Mode Water[J].J Phys Oceanog,2002,32(5):1308-1321,doi:10.1175/1520-0485(2002)032<1308:ETDLAS>2.0.CO;2.
• [42]Sallée J-B,Wienders N,Speer K,et al.Formation of subantarctic mode water in the southeastern Indian Ocean[J].Ocean Dynam,2006,56(5-6):525-542,doi:10.1007/s10236-005-0054-x.
• [43]Gong D and Wang S,Definition of Antarctic Oscillation index[J].Geophys Res Lett,1999,26(4):459-462,doi:10.1029/1999GL900003.
• [44]Biastoch A,B9ning C W and Lutjeharms J.Agulhas leakage dynamics affects decadal variability in Atlantic overturning circulation[J].Nature,2008,456(7221):489-492,doi:10.1038/nature07426.

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