Indian Ocean Capacitor Effect on Indo–Western Pacific Climate during the Summer following El Niño
Tóm tắt
Significant climate anomalies persist through the summer (June–August) after El Niño dissipates in spring over the equatorial Pacific. They include the tropical Indian Ocean (TIO) sea surface temperature (SST) warming, increased tropical tropospheric temperature, an anomalous anticyclone over the subtropical northwest Pacific, and increased mei-yu–baiu rainfall over East Asia. The cause of these lingering El Niño effects during summer is investigated using observations and an atmospheric general circulation model (GCM). The results herein indicate that the TIO warming acts like a capacitor anchoring atmospheric anomalies over the Indo–western Pacific Oceans. It causes tropospheric temperature to increase by a moist-adiabatic adjustment in deep convection, emanating a baroclinic Kelvin wave into the Pacific. In the northwest Pacific, this equatorial Kelvin wave induces northeasterly surface wind anomalies, and the resultant divergence in the subtropics triggers suppressed convection and the anomalous anticyclone. The GCM results support this Kelvin wave–induced Ekman divergence mechanism. In response to a prescribed SST increase over the TIO, the model simulates the Kelvin wave with low pressure on the equator as well as suppressed convection and the anomalous anticyclone over the subtropical northwest Pacific. An additional experiment further indicates that the north Indian Ocean warming is most important for the Kelvin wave and northwest Pacific anticyclone, a result corroborated by observations.
These results have important implications for the predictability of Indo–western Pacific summer climate: the spatial distribution and magnitude of the TIO warming, rather than simply whether there is an El Niño in the preceding winter, affect summer climate anomalies over the Indo–western Pacific and East Asia.
Từ khóa
Tài liệu tham khảo
Alexander, 2002, The atmospheric bridge: The influence of ENSO teleconnections on air–sea interaction over the global oceans., J. Climate, 15, 2205, 10.1175/1520-0442(2002)015<2205:TABTIO>2.0.CO;2
Alexander, 2004, Broadening the atmospheric bridge paradigm: ENSO teleconnections to the tropical West Pacific-Indian Oceans over the seasonal cycle and to the North Pacific in summer., 10.1029/147GM05
Annamalai, 2005, Southwest Indian Ocean SST variability: Its local effect and remote influence on Asian monsoons., J. Climate, 18, 4150, 10.1175/JCLI3533.1
Behera, 2000, Simulation of interannual SST variability in the tropical Indian Ocean., J. Climate, 13, 3487, 10.1175/1520-0442(2000)013<3487:SOISVI>2.0.CO;2
Chiang, 2002, Tropical tropospheric temperature variations caused by ENSO and their influence on the remote tropical climate., J. Climate, 15, 2616, 10.1175/1520-0442(2002)015<2616:TTTVCB>2.0.CO;2
Chiang, 2005, Mechanisms of remote tropical surface warming during El Niño., J. Climate, 18, 4130, 10.1175/JCLI3529.1
Copsey, 2006, Recent trends in sea level pressure in the Indian Ocean region., Geophys. Res. Lett., 33, L19712, 10.1029/2006GL027175
Deser, 2006, Simulation of the 1976/77 climate transition over the North Pacific: Sensitivity to tropical forcing., J. Climate, 19, 6170, 10.1175/JCLI3963.1
Deser, 2004, Pacific interdecadal climate variability: Linkages between the tropics and the North Pacific during boreal winter since 1900., J. Climate, 17, 3109, 10.1175/1520-0442(2004)017<3109:PICVLB>2.0.CO;2
Du, 2008, Role of atmospheric adjustments in the tropical Indian Ocean warming during the 20th century in climate models., Geophys. Res. Lett., 35, L08712, 10.1029/2008GL033631
Du, 2009, Role of air–sea interaction in the long persistence of El Niño–induced North Indian Ocean warming., J. Climate, 10.1175/2008JCLI2590.1
Emanuel, 1997, Reply to comments by Bjorn Stevens, David A. Randall, Xin Lin and Michael T. Montgomery on ‘On large-scale circulations in convecting atmospheres.’., Quart. J. Roy. Meteor. Soc., 123, 1779
Enfield, 1997, Tropical Atlantic SST variability and its relation to El Niño–Southern Oscillation., J. Geophys. Res., 102, 929, 10.1029/96JC03296
Fu, 1988, The relationship between ENSO and climate anomaly in China during the summer time., Sci. Atmos. Sin., 12, 133
Gill, 1980, Some simple solutions for heat-induced tropical circulation., Quart. J. Roy. Meteor. Soc., 106, 447, 10.1002/qj.49710644905
Harrison, 1996, The COADS sea level pressure signal: A near-global El Niño composite and time series view, 1946–93., J. Climate, 9, 3025, 10.1175/1520-0442(1996)009<3025:TCSLPS>2.0.CO;2
Huang, 2002, Interannual variability in the tropical Indian Ocean., J. Geophys. Res., 107, 3199, 10.1029/2001JC001278
Huang, 1989, The influence of ENSO on the summer climate change in China and its mechanism., Adv. Atmos. Sci., 6, 21, 10.1007/BF02656915
Huang, 2004, Recent advances in studies of the interaction between the East Asian winter and summer monsoons and ENSO cycle., Adv. Atmos. Sci., 21, 407, 10.1007/BF02915568
Kalnay, 1996, The NCEP/NCAR 40-Year Reanalysis Project., Bull. Amer. Meteor. Soc., 77, 437, 10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2
Kang, 2002, Intercomparison of the climatological variations of Asian summer monsoon precipitation simulated by 10 GCMs., Climate Dyn., 19, 383, 10.1007/s00382-002-0245-9
Kawamura, 2001, Role of equatorially asymmetric sea surface temperature anomalies in the Indian Ocean in the Asian summer monsoon and El Niño–Southern Oscillation coupling., J. Geophys. Res., 106, 4681, 10.1029/2000JD900610
Klein, 1999, Remote sea surface temperature variations during ENSO: Evidence for a tropical atmospheric bridge., J. Climate, 12, 917, 10.1175/1520-0442(1999)012<0917:RSSTVD>2.0.CO;2
Kosaka, 2006, Structure and dynamics of the summertime Pacific-Japan teleconnection pattern., Quart. J. Roy. Meteor. Soc., 132, 2009, 10.1256/qj.05.204
Kumar, 1998, Specification of regional sea surface temperatures in atmospheric general circulation model simulations., J. Geophys. Res., 103, 8901, 10.1029/98JD00427
Kumar, 2003, The nature and causes for the delayed atmospheric response to El Niño., J. Climate, 16, 1391, 10.1175/1520-0442-16.9.1391
Lau, 2003, Atmosphere–ocean variations in the Indo-Pacific sector during ENSO episodes., J. Climate, 16, 3, 10.1175/1520-0442(2003)016<0003:AOVITI>2.0.CO;2
Lau, 2005, Influences of ENSO-induced Indo–western Pacific SST anomalies on extratropical atmospheric variability during the boreal summer., J. Climate, 18, 2922, 10.1175/JCLI3445.1
Lengaigne, 2006, Influence of the seasonal cycle on the termination of El Niño events in a coupled general circulation model., J. Climate, 19, 1850, 10.1175/JCLI3706.1
Li, 2008, Tropical Indian Ocean basin warming and East Asian summer monsoon: A multiple AGCM study., J. Climate, 21, 6080, 10.1175/2008JCLI2433.1
Liu, 2004, A gap in the Indo-Pacific warm pool over the South China Sea in boreal winter: Seasonal development and interannual variability., J. Geophys. Res., 109, C07012, 10.1029/2003JC002179
Matsuno, 1966, Quasi-geostrophic motions in the equatorial area., J. Meteor. Soc. Japan, 44, 25, 10.2151/jmsj1965.44.1_25
Murakami, 1994, Summer monsoon over the Asian continent and western North Pacific., J. Meteor. Soc. Japan, 72, 719, 10.2151/jmsj1965.72.5_719
Murtugudde, 1999, Interannual variability of the dynamics and thermodynamics, and mixed layer processes in the Indian Ocean., J. Climate, 12, 2300, 10.1175/1520-0442(1999)012<2300:IVOTDA>2.0.CO;2
Neelin, 2005, Moist teleconnection mechanisms for the tropical South American and Atlantic sector., J. Climate, 18, 3928, 10.1175/JCLI3517.1
Nitta, 1987, Convective activities in the tropical western Pacific and their impact on the Northern Hemisphere summer circulation., J. Meteor. Soc. Japan, 65, 373, 10.2151/jmsj1965.65.3_373
Ohba, 2006, A role of zonal gradient of SST between the Indian Ocean and the western Pacific in localized convection around the Philippines., SOLA, 2, 176, 10.2151/sola.2006-045
Rayner, 2006, Improved analyses of changes and uncertainties in sea surface temperature measured in situ since the mid-nineteenth century: The HadSST2 dataset., J. Climate, 19, 446, 10.1175/JCLI3637.1
Roeckner, 2003, Atmospheric general circulation model ECHAM5: Part I.
Schott, 2008, Indian Ocean circulation and climate variability., Rev. Geophys.
Shen, 2001, Simulation of the 1998 East Asian summer monsoon by the CCSR/NIES AGCM., J. Meteor. Soc. Japan, 79, 741, 10.2151/jmsj.79.741
Sobel, 2002, The ENSO signal in tropical tropospheric temperature., J. Climate, 15, 2702, 10.1175/1520-0442(2002)015<2702:TESITT>2.0.CO;2
Su, 2003, The scatter in tropical average precipitation anomalies., J. Climate, 16, 3966, 10.1175/1520-0442(2003)016<3966:TSITAP>2.0.CO;2
Su, 2001, Tropical teleconnection and local response to SST anomalies during the 1997–98 El Niño., J. Geophys. Res., 106, 20025, 10.1029/2000JD000124
Terao, 2005, East-west SST contrast over the tropical oceans and the post E1 Niño western North Pacific summer monsoon., Geophys. Res. Lett., 32, L15706, 10.1029/2005GL023010
Tokinaga, 2004, Seasonal transition of SST anomalies in the tropical Indian Ocean during El Niño and Indian Ocean dipole years., J. Meteor. Soc. Japan, 82, 1007, 10.2151/jmsj.2004.1007
Trenberth, 1998, Progress during TOGA in understanding and modeling global teleconnections associated with tropical sea surface temperatures., J. Geophys. Res., 103, 14291, 10.1029/97JC01444
Ueda, 1995, Abrupt seasonal change of large-scale convective activity over the western Pacific in the northern summer., J. Meteor. Soc. Japan, 73, 795, 10.2151/jmsj1965.73.4_795
Ueda, 2009, Important factors for the development of the Asian–northwest Pacific summer monsoon., J. Climate, 10.1175/2008JCLI2341.1
Vecchi, 2006, The termination of the 1997–98 El Niño. Part I: Mechanisms of oceanic change., J. Climate, 19, 2633, 10.1175/JCLI3776.1
Wang, 2002, Rainy season of the Asian-Pacific summer monsoon., J. Climate, 15, 386, 10.1175/1520-0442(2002)015<0386:RSOTAP>2.0.CO;2
Wang, 2000, Pacific–East Asia teleconnection: How does ENSO affect East Asian climate?, J. Climate, 13, 1517, 10.1175/1520-0442(2000)013<1517:PEATHD>2.0.CO;2
Wang, 2003, Atmosphere–warm ocean interaction and its impact on Asian–Australian monsoon variability., J. Climate, 16, 1195, 10.1175/1520-0442(2003)16<1195:AOIAII>2.0.CO;2
Wang, 2005, Fundamental challenge in simulation and prediction of summer monsoon rainfall., Geophys. Res. Lett., 32, L15711, 10.1029/2005GL022734
Wang, 1999, Western Pacific interannual variability associated with the El Niño–Southern Oscillation., J. Geophys. Res., 104, 5131, 10.1029/1998JC900090
Wang, 2006, Interannual variability of the South China Sea associated with El Niño., J. Geophys. Res., 111, C03023
Watanabe, 2000, Atmosphere-ocean thermal coupling in the North Atlantic: A positive feedback., Quart. J. Roy. Meteor. Soc., 126, 3343, 10.1002/qj.49712657017
Watanabe, 2003, A moist linear baroclinic model: Coupled dynamical–convective response to El Niño., J. Climate, 16, 1121, 10.1175/1520-0442(2003)16<1121:AMLBMC>2.0.CO;2
Webster, 1999, Coupled oceanic-atmospheric dynamics in the Indian Ocean during 1997-98., Nature, 401, 356, 10.1038/43848
Wu, 1995, Neighborhood response of rainfall to tropical sea surface temperature anomalies. Part I: Numerical experiment., Chinese J. Atmos. Sci., 19, 422
Wu, 1995, Neighborhood response of rainfall to tropical sea surface temperature anomalies. Part II: Data analysis., Chinese J. Atmos. Sci., 19, 663
Wu, 2006, Local air–sea relationship in observations and model simulations., J. Climate, 19, 4914, 10.1175/JCLI3904.1
Wu, 2008, An asymmetric mode of tropical Indian Ocean rainfall variability in boreal spring., J. Geophys. Res., 113, D05104, 10.1029/2007JD009316
Xie, 1996, Analyses of global monthly precipitation using gauge observations, satellite estimates, and numerical model predictions., J. Climate, 9, 840, 10.1175/1520-0442(1996)009<0840:AOGMPU>2.0.CO;2
Xie, 2004, The shape of continents, air-sea interaction, and the rising branch of the Hadley circulation., 10.1007/978-1-4020-2944-8_5
Xie, 1994, A coupled ocean-atmosphere model of relevance to the ITCZ in the eastern Pacific., Tellus, 46A, 340, 10.3402/tellusa.v46i4.15484
Xie, 2002, Structure and mechanisms of South Indian Ocean climate variability., J. Climate, 15, 864, 10.1175/1520-0442(2002)015<0864:SAMOSI>2.0.CO;2
Xie, 2003, Summer upwelling in the South China Sea and its role in regional climate variations., J. Geophys. Res., 108, 3261, 10.1029/2003JC001867
Yang, 2007, Impact of the Indian Ocean SST basin mode on the Asian summer monsoon., Geophys. Res. Lett., 34, L02708, 10.1029/2006GL028571
Yoo, 2006, Variability of the Indian Ocean sea surface temperature and its impacts on Asian-Australian monsoon climate., J. Geophys. Res., 111, D03108, 10.1029/2005JD006001