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Vinu K. Valsala and Motoyoshi Ikeda

three-dimensional flow pattern of the ITF over the Indian Ocean (especially the ITF entrance region at the Indonesian Straits and the Somali upwelling region where the ITF routes are significantly redirected) by following both the Lagrangian-type trajectories and the passive tracer pathways along with the temperature and salinity; 2) to determine the significance of seasonal changes in the Indian Ocean in spreading the ITF pathways; and 3) to examine the effects of the ITF on temperature and

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Clémentde Boyer Montégut, Jérôme Vialard, S. S. C. Shenoi, D. Shankar, Fabien Durand, Christian Ethé, and Gurvan Madec

of the SST seasonal cycle in the AS because seasons of strongest positive flux coincide with the thinnest mixed layer. Another striking result is the important role of salinity in the seasonal heat budget of the NIO. Salinity effects can explain why winter cooling is greater in the western than in the eastern AS ( Table 2 ). Heat accumulated in the barrier layer in the eastern AS warms the mixed layer in winter by 0.4°C, while the western AS experiences a subsurface heat loss of −0.8°C. SSS02

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Lisan Yu, Xiangze Jin, and Robert A. Weller

that NCEP2 may not have the same representation of variability as NCEP1. The STD pattern shown here substantiates the viewpoint that NCEP2 is not as good at representing the variability in Q net . 6. Role of Q net in the seasonal and interannual variabilities of SST The physical representation of Q net from the six products is tested using a physical relation. If the effects of oceanic processes are not considered, Q net is related to the change of the surface mixed layer temperature through

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Jean Philippe Duvel and Jérôme Vialard

1. Introduction The intraseasonal variability (ISV) of deep convection is one of the most organized and reproducible large-scale perturbations in the Tropics, with maximum amplitude over the Indo-Pacific region. Over the Indian Ocean, this ISV has a strong seasonality. During the summer monsoon, the convective perturbation propagates northward from the equator to the Indian peninsula with maximum amplitude over the Bay of Bengal (see Lawrence and Webster 2002 ). These summer perturbations are

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J. Stuart Godfrey, Rui-Jin Hu, Andreas Schiller, and R. Fiedler

and generate small-scale mixing. The existence of this maximum may explain the sensitivity of the OFES results to the inclusion of daily winds. Part II of this study explores similar issues in a model with realistic coastlines and wind stresses. The “minimum depth” principle is generalized to accommodate this more realistic case, and we explore the effects of adding seasonal wind stress variations to the same annual mean winds. Acknowledgments This paper has been 10 years in preparation. A

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Rui-Jin Hu and J. Stuart Godfrey

the way water colder than minimum SST joins the southward Ekman transport in the real Indian Ocean. In this paper, five of the most obvious limitations of the model of Part I are addressed—unrealistic basin shape, annual mean wind stress, and surface heat boundary conditions, plus lack of seasonality of stress and of heat fluxes. In the first experiment of the present paper, the idealized basin shape and wind stresses of Part I were replaced with (a reasonable approximation to) the observed

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Joaquim Ballabrera-Poy, Eric Hackert, Raghu Murtugudde, and Antonio J. Busalacchi

thermodynamics of the tropical Indian Ocean. J. Climate , 12 , 2300 – 2326 . Murtugudde , R. , R. Seager , and A. Busalacchi , 1996 : Simulation of the tropical oceans with an ocean GCM coupled to an atmospheric mixed-layer model. J. Climate , 9 , 1795 – 1815 . Murtugudde , R. , A. J. Busalacchi , and J. Beauchamp , 1998 : Seasonal-to-interannual effects of the Indonesian throughflow on the tropical Indo–Pacific basin. J. Geophys. Res. , 103 , 21425 – 21441 . Murtugudde , R. G

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J. C. Hermes, C. J. C. Reason, and J. R. E. Lutjeharms

Current is in fact enhanced by a further 30 Sv from this recirculation subgyre, implying that of the three sources it contributes the most volume flux to the Agulhas Current. It is also possible that the recirculation may be influenced by seasonal shifts of the south Indian Ocean anticyclone ( Preston-Whyte and Tyson 1988 ). Since the recirculation seems to be the major contributor to the Agulhas Current it is conceivable that a seasonal variability to the inflow to the Agulhas Current may occur. The

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H. Annamalai, H. Okajima, and M. Watanabe

imposed in the tropical Indo-Pacific region from 30°S to 30°N and seasonally varying climatological SSTs are imposed elsewhere. The tropical Pacific Ocean (TPO) runs are similar to the TIP runs, except that SST anomalies are inserted only into the tropical Pacific. The tropical Indian Ocean (TIO) runs are like the TIP runs, but with SST anomalies imposed only in the tropical Indian Ocean. This set of experiments is expected to reveal the individual and combined effects of SST anomalies on the local

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Bohua Huang and J. Shukla

interannual variability in the tropical Indian Ocean. Previous studies have emphasized the effects of the surface heat flux over the tropical Indian Ocean (e.g., Klein et al. 1999 ; Venzke et al. 2000 ; Lau and Nath 2000 , 2003 ; Baquero-Bernal et al. 2002 ; Li et al. 2003 ; Yu and Lau 2004 ). In this study, we further examine the role of the ocean dynamics in the tropical air–sea feedback. We also distinguish the tropical air–sea interaction from those in the subtropical Indian Ocean where the

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