Role of the eastern boundary-generated waves on the termination of 1997 Indian Ocean Dipole event
Tóm tắt
The termination of Indian Ocean Dipole (IOD) events is examined in terms of equatorial wave dynamics. In situ and satellite observations combined with an output from a linear wave model are used in this study. Our emphasis is on the 1997 IOD event but our results apply to other positive IOD events as well. We find that the termination of anomalously cold sea surface temperature (SST) in the eastern pole of the dipole is associated with a warming tendency caused by the net surface heat fluxes. However, net surface heat fluxes alone cannot explain the total change in the SST. We show that during the peak phase of an IOD event, the weakening of zonal heat advection caused by eastern boundary-generated Rossby waves combined with the reduction of vertical entrainment and diffusion creates favorable conditions for surface heat fluxes to warm the SST in the eastern basin.
Tài liệu tham khảo
Ashok K, Guan Z, Yamagata T (2003) Influence of the Indian Ocean Dipole on the Australian winter rainfall. Geophys Res Lett 30(15):1821. https://doi.org/10.1029/2003GL017926
Bonjean F, Lagerloef GSE (2002) Diagnostic model and analysis of the surface currents in the tropical Pacific Ocean. J Phys Oceanogr 32:2938–2954
Chambers DP, Tapley BD, Stewart RH (1999) Amomalous warming in the Indian Ocean coincident with El Niño. J Geophys Res 104:3035–3047. https://doi.org/10.1029/1998JC900085
Chen W, Han Y, Li DW (2016) Interannual variability of equatorial eastern Indian Ocean upwelling: local versus remote forcing. J Phys Oceanogr 46:789–807. https://doi.org/10.1175/JPO-D-15-0117.1
Dee DP, Uppala SM, Simmons AJ et al (2011) The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q J R Meteorol Soc 137:553–597
Du Y, Qu T, Meyers G (2008) Interannual variability of sea surface temperature off Java and Sumatra in a global GCM. J Climate 21:2451–2465. https://doi.org/10.1175/2007JCLI1753.1
Feng M, Meyers G (2003) Interannual variability in the tropical Indian Ocean: a two-year time-scale of Indian Ocean Dipole. Deep-Sea Res 50:2263–2284
Horii T, Hase H, Ueki I, Masumoto Y (2008) Oceanic precondition and evolution of the 2006 Indian Ocean Dipole. Geophys Res Lett 35:L03607. https://doi.org/10.1029/2007GL032464
Horii T, Ueki I, Ando K, Mizuno K (2013) Eastern Indian Ocean warming associated with the negative Indian Ocean dipole: a case study of the 2010 event. J Geophys Res Oceans 118:536–549. https://doi.org/10.1002/jgrc.20071
Kumar BP, Vialard J, Lengaigne M, Murty VSN, McPhaden MJ (2011) TropFlux: air-sea fluxes for the global tropical oceans–description and evaluation against observations. Clim Dyn. https://doi.org/10.1007/s00382-011-1115-0
Lee T, Fukumori I, Tang B (2004) Temperature advection: internal versus external processes. J Phys, Oceanogr 34:1936–1944
Li T, Zhang Y, Lu E, Wang D (2002) Relative role of dynamic and thermodynamic processes in the development of the Indian Ocean dipole: an OGCM diagnosis. Geophys Res Lett 29(23):2110. https://doi.org/10.1029/2002GL05789
McPhaden MJ (1982) Variability in the central equatorial Indian Ocean, part II: oceanic heat and turbulent energy balance. J Mar Res 40:403–419
McPhaden MJ, Nagura M (2014) Indian Ocean dipole interpreted in terms of recharge oscillator theory. Clim Dyn 42(5–6):1569–1586
Meyers GA, McIntosh PC, Pigot L, Pook MJ (2007) The year of El Niño, La Niña, and interactions with the tropical Indian Ocean. J Clim 20:2872–2880
Murtugudde R, McCreary JP, Busalacchi AJ (2000) Oceanic processes associated with anomalous events in the Indian Ocean with relevance to 1997–98. J Geophys Res 105(C2):3295–3306
Nagura M, McPhaden MJ (2010a) The dynamics of zonal current variations associated with the Indian Ocean Dipole. J Geophys Res 115:C11026. https://doi.org/10.1029/2010JC006423
Nagura M, McPhaden MJ (2010b) Wyrtki jet dynamics: seasonal variability. J Geophys Res 115:C07009. https://doi.org/10.1029/2009JC005922
Nagura M, McPhaden MJ (2012) The dynamics of wind-driven intraseasonal variability in the equatorial Indian Ocean. J Geophys Res 115:C07009. https://doi.org/10.1029/2011JC007405
Picaut J, Masia F, du Penhoat Y (1997) An advective-reflective conceptual model for the oscillatory nature of the ENSO. Science 277:663–666
Rao SA, Yamagata T (2004) Abrupt termination of Indian Ocean dipole events in response to instraseasonal oscillations. Geophys Res Lett 31:L19306. https://doi.org/10.1029/2004GL020842
Rao SA, Behera SK, Masumoto Y, Yamagata T (2002) Interannual subsurface variability in the tropical Indian Ocean with a special emphasis on the Indian Ocean dipole. Deep Sea Res 49:1549–1572
Reynolds RW, Rayner NA, Smith TM, Stokes DC, Wang WQ (2002) An improved in situ and satellite SST analysis for climate. J Climate 15:1609–1625
Saji NH, Yamagata T (2003) Possible impacts of Indian Ocean Dipole mode events on global climate. Clim Res 25:151–169
Saji NH, Goswami BN, Vinayachandran PN, Yamagata T (1999) A dipole mode in the tropical Indian Ocean. Nature 410:360–363
Tokinaga H, Tanimoto Y (2004) Seasonal transition of SST anomalies in the tropical Indian ocean during El Nino and Indian Ocean dipole years. J Meteor Soc Japan 82:1007–1018
Vialard J, Foltz GR, McPhaden MJ, Duvel JP, de Boyer Montégut C (2008) Strong Indian Ocean sea surface temperature signals associated with the Madden-Julian Oscillation in late 2007 and early 2008. Geophys Res Lett 35:L19608. https://doi.org/10.1029/2008GL035238
Vinayachandran PN, Saji NH, Yamagata T (1999) Response of the equatorial Indian Ocean to an unusual wind event during 1994. Geophys Res Lett 26:1613–1616. https://doi.org/10.1029/1999GL900179
Wang W, McPhaden MJ (1999) The surface layer heat balance in the equatorial Pacific Ocean. Part I: mean seasonal cycle. J Phys Oceanogr 29:1812–1831
Webster PJ, Moore AW, Loschnigg JP, Leben RR (1999) Coupled ocean-atmosphere dynamics in the Indian Ocean during 1997–98. Nature 401:356–360
Yamagata T, Behera SK, Luo J-J, Masson S, Jury M, Rao SA (2004) Copled ocean-atmosphere variability in the tropical Indian Ocean. Earth Clim Ocean Atmos Interact Geophys Monogr 147:189–212
Yuan D, Liu H (2009) Long-wave dynamics of sea level variations during Indian Ocean Dipole events. J Phys Oceanogr 39:1115–1132