This research was supported by the Visiting Scientist Program at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory (NOAA/GFDL), administered by the University Corporation for Atmospheric Research (UCAR). Analysis and graphics were done using the freeware package Ferret (information available online at http://ferret.pmel.noaa.gov/). We acknowledge the TAO project office for making the TAO and PIRATA buoy data easily and readily available; we are grateful to Drs. Yukio Masumoto and Yoshi Kuroda for kindly making the high-frequency Indian Ocean TRITON data available. Helpful comments and suggestions were received from the CLIVAR Indian Ocean Panel, Ed Harrison, Scott Song, Tony Rosati, Andrew Wittenberg, Bob Hallberg, Brian Arbic, and Sebastian Ilcane. We acknowledge the careful reading by and useful suggestions from the three anonymous reviewers.
Annamalai, H., , and R. Murtugudde, 2004: Role of the Indian Ocean in regional climate variability. Earth Climate: The Ocean–Atmosphere Interaction,Geophys. Monogr., Vol. 147, Amer. Geophys. Union, 213–246.
Arbic, B. K., , S. T. Garner, , R. W. Hallberg, , and H. L. Simmons, 2004: The accuracy of surface elevations in forward global barotropic and baroclinic tide models. Deep-Sea Res. II, 51 , 3069–3101.
Argo Science Team, 2001: The global array of profiling floats. Observing the Oceans in the 21st Century, C. J. Koblinsky and N. R. Smith, Eds., GODAE Project Office, 248–258.
Ballabrera-Poy, J., , E. Hackert, , R. Murtugudde, , and A. J. Busalacchi, 2007: An observing system simulation experiment for an optimal moored instrument array in the tropical Indian Ocean. J. Climate, 20 , 3284–3299.
Bhat, G. S., , G. A. Vecchi, , and S. Gadgil, 2004: Sea surface temperature of the Bay of Bengal derived from TRMM. J. Atmos. Oceanic Technol., 21 , 1283–1290.
Bond, N. A., , and G. A. Vecchi, 2003: On the Madden–Julian oscillation and precipitation in Oregon and Washington. Wea. Forecasting, 18 , 600–613.
Boyer, T. F., , S. Levitus, , J. L. Antonov, , R. A. Locarnini, , and H. E. Garcia, 2005: Linear trends in salinity or the World Oceans, 1955–1998. Geophys. Res. Lett., 32 .L01604, doi:10.1029/2004GL021791.
CLIVAR–GOOS Indian Ocean Panel, 2006: Understanding the role of the Indian Ocean in the climate system—Implementation plan for sustained observations. WCRP Informal Rep. 5/2006, ICPO Publications Series 100, GOOS Rep. 152, 78 pp.
Duvel, J. P., , R. Roca, , and J. Vialard, 2004: Ocean mixed layer temperature variations induced by intraseasonal convective perturbations over the Indian Ocean. J. Atmos. Sci., 61 , 1004–1023.
ECMWF, 1989: The description of the ECMWF/WCRP level III—A global atmospheric data archive. ECMWF Tech. Attachment, 72 pp. [Available from ECMWF, Shinfield Park, Reading RG2 9AX, United Kingdom.].
Eriksen, C. C., , T. J. Osse, , R. D. Light, , T. Wen, , T. W. Lehman, , P. L. Sabin, , J. W. Ballard, , and A. M. Chiodi, 2001: Seaglider: A long-range autonomous underwater vehicle for oceanographic research. IEEE J. Oceanic Eng., 26 , 424–436.
Fu, X., , B. Wang, , T. Li, , and J. McCreary, 2003: Coupling between northward propagating, intraseasonal oscillations and sea surface temperature in the Indian Ocean. J. Atmos. Sci., 60 , 1733–1753.
Gualdi, S., , E. Guilyardi, , A. Navarra, , S. Masina, , and P. Delecluse, 2003: The interannual variability in the Indian Ocean as simulated by a CGCM. Climate Dyn., 20 , 567–582.
Harrison, D. E., 1989: On climatological monthly mean wind stress and wind stress curl fields over the World Ocean. J. Climate, 2 , 57–70.
Harrison, D. E., , and N. K. Larkin, 1998: The COADS sea level pressure signal: A near-global El Niño composite and time series view, 1946–1993. J. Climate, 9 , 3025–3055.
Hayes, S. P., , L. J. Mangum, , J. Picaut, , A. Sumi, , and K. Takeuchi, 1991: TOGA-TAO: A moored array for real-time measurements of the tropical Pacific Ocean. Bull. Amer. Meteor. Soc., 72 , 339–347.
Kummerow, C., and Coauthors, 2000: The status of the Tropical Rainfall Measuring Mission (TRMM) after two years in orbit. J. Appl. Meteor., 39 , 1965–1982.
Large, W. G., , and S. Pond, 1981: Open-ocean momentum-flux measurements in moderate to strong winds. J. Phys. Oceanogr., 11 , 324–336.
Larkin, N. K., , and D. E. Harrison, 2001: Tropical Pacific ENSO cold events, 1946–95: SST, SLP, and surface wind composite anomalies. J. Climate, 14 , 3904–3931.
Lau, N. C., , and M. J. Nath, 2003: Atmosphere–ocean variations in the Indo–Pacific sector during ENSO episodes. J. Climate, 16 , 3–20.
Levitus, S., 1982: Climatological Atlas of the World Ocean. NOAA Prof. Paper 13, 173 pp. and 17 microfiche.
Levitus, S., , J. Antonov, , and T. Boyer, 2005: Warming of the world ocean, 1955–2003. Geophys. Res. Lett., 32 .L02604, doi:10.1029/2004GL021592.
Loshnigg, J., , and P. J. Webster, 2000: A coupled ocean–atmosphere system of SST modulation for the Indian Ocean. J. Climate, 13 , 3342–3360.
Madden, R. A., , and P. R. Julian, 1994: Observations of the 40–50-day tropical oscillation: A review. Mon. Wea. Rev., 122 , 814–837.
Maloney, E. D., , and D. L. Hartmann, 2000: Modulation of eastern North Pacific hurricane activity in the Gulf of Mexico by the Madden–Julian oscillation. Science, 287 , 2002–2004.
Mariano, A. J., , E. H. Ryan, , B. D. Perkins, , and S. Smithers, 1995: The Mariano global surface velocity analysis 1.0. Tech. Rep. CG-D-34-95, Office of Engineering, Logistics, and Development, U.S. Coast Guard, 55 pp.
Masumoto, Y., , H. Hase, , Y. Kuroda, , H. Matsuura, , and K. Takeuchi, 2005a: Intraseasonal variability in the upper layer currents observed in the eastern equatorial Indian Ocean. Geophys. Res. Lett., 32 .L02607, doi:10.1029/2004GL021896.
Masumoto, Y., , V. S. N. Murty, , M. Jury, , M. J. McPhaden, , P. Hacker, , J. Vialard, , R. Molcard, , and G. Meyers, cited. 2005b: Tropical Indian Ocean mooring array: Present status and future plans. [Available online at http://ioc.unesco.org/oopc/oopc9/Tropical_Indian_Moorings.pdf.].
McPhaden, M. J., and Coauthors, 1998: The Tropical Ocean-Global Atmosphere (TOGA) observing system: A decade of progress. J. Geophys. Res., 103 , 14169–14240.
Meyers, G., and Coauthors, 2000: Monsoon, seasonal and interannual applications of an Indian Ocean observing system. Observing the Ocean in the 21st Century, C. J. Koblinsky and N. R. Smith, Eds., Bureau of Meteorology, 48–65.
Miyama, T., , J. P. McCreary, , T. G. Jensen, , J. Loschnigg, , S. Godfrey, , and A. Ishida, 2003: Structure and dynamics of the Indian Ocean cross-equatorial cell. Deep-Sea Res. II, 50 , 2023–2047.
Mo, K. C., , and R. W. Higgins, 1998: Tropical convection and precipitation regimes in the western United States. J. Climate, 11 , 2404–2423.
Nicholls, N., 1995: All-India summer monsoon rainfall and sea surface temperature around northern Australia and Indonesia. J. Climate, 8 , 1463–1467.
Oke, P. R., , and A. Schiller, 2007: A model-based assessment and design of a tropical Indian Ocean mooring array. J. Climate, 20 , 3269–3283.
Pacanowski, R. C., , and S. G. H. Philander, 1981: Parametrizations of vertical mixing in numerical models of tropical oceans. J. Phys. Oceanogr., 11 , 1443–1451.
Premkumar, K., , M. Ravichandran, , S. R. Kalsi, , D. Sengupta, , and S. Gadgil, 2000: First results from a new observational system over the Indian seas. Curr. Sci., 78 , 323–330.
Reynolds, R. W., , and T. M. Smith, 1994: Improved global sea surface temperature analyses using optimum interpolation. J. Climate, 7 , 929–948.
Reynolds, R. W., , N. A. Rayner, , T. M. Smith, , D. C. Stokes, , and W. Wang, 2002: An improved in situ and satellite SST analysis for climate. J. Climate, 15 , 1609–1625.
Richardson, P. L., , and T. K. McKee, 1989: Surface velocity in the equatorial oceans (20N-20S) calculated from historical ship drifts. WHOI Tech. Rep. WHOI-89-9, Woods Hole Oceanographic Institution, Woods Hole, MA, 50 pp.
Saji, N. H., , B. N. Goswami, , P. N. Vinayachandran, , and T. Yamagata, 1999: A dipole mode in the tropical Indian Ocean. Nature, 401 , 360–363.
Schiller, A., , S. E. Wijffels, , and G. A. Meyers, 2004: Design requirements for an Argo float array in the Indian Ocean inferred from observing system simulation experiments. J. Atmos. Oceanic Technol., 21 , 1598–1620.
Schott, F. A., , J. P. McCreary, , and G. C. Johnson, 2004: Shallow overturning circulations of the tropical–subtropical oceans. Earth Climate: The Ocean–Atmosphere Interaction,Geophys. Monogr., Vol. 147, Amer. Geophys. Union, 261–304.
Sengupta, D., , and M. Ravichandran, 2001: Oscillations of Bay of Bengal sea surface temperature during the 1998 summer monsoon. Geophys. Res. Lett., 28 , 2033–2036.
Sengupta, D., , R. Senan, , V. S. N. Murty, , and V. Fernando, 2004: A biweekly mode in the equatorial Indian Ocean. J. Geophys. Res., 109 .C10003, doi:10.1029/2004JC002329.
Servain, J., , A. J. Busalacchi, , M. J. McPhaden, , A. D. Moura, , G. Reverdin, , M. Vianna, , and S. E. Zebiak, 1998: A Pilot Research Moored Array in the Tropical Atlantic (PIRATA). Bull. Amer. Meteor. Soc., 79 , 2019–2031.
Sibenac, M., , T. Podder, , W. Kirkwood, , and H. Thomas, 2004: Autonomous underwater vehicles for ocean research: Current needs and state of the art technologies. Mar. Technol. Soc. J., 38 , 2. 63–72.
Simmons, H. L., , R. W. Hallberg, , and B. K. Arbic, 2004: Internal wave generation in a global baroclinic tide model. Deep-Sea Res. II, 51 , 3043–3068.
Smith, W. H. F., , and D. T. Sandwell, 1997: Global sea floor topography from satellite altimetry and ship depth soundings. Science, 277 , 1956–1962.
Song, Q. N., , G. A. Vecchi, , and A. Rosati, 2007: Indian Ocean variability in the GFDL coupled climate model. J. Climate, 20 , 2895–2916.
Vecchi, G. A., , and D. E. Harrison, 2002: Monsoon breaks and subseasonal sea surface temperature variability in the Bay of Bengal. J. Climate, 15 , 1485–1493.
Vecchi, G. A., , and D. E. Harrison, 2003: On the termination of the 2002–03 El Niño event. Geophys. Res. Lett., 30 .1964, doi:10.1029/2003GL017564.
Vecchi, G. A., , and N. A. Bond, 2004: The Madden–Julian Oscillation (MJO) and northern high latitude wintertime surface air temperatures. Geophys. Res. Lett., 31 .L04104, doi:10.1029/2003GL018645.
Vecchi, G. A., , and D. E. Harrison, 2004: Interannual Indian rainfall variability and Indian Ocean sea surface temperature anomalies. Earth Climate: The Ocean–Atmosphere Interaction,Geophys. Monogr., Vol. 147, Amer. Geophys. Union, 247–260.
Vecchi, G. A., , and D. E. Harrison, 2005: The termination of the 1997–98 El Niño. Part I: Mechanisms of oceanic change. J. Climate, 19 , 2633–2646.
Vecchi, G. A., , S-P. Xie, , and A. Fischer, 2004: Air–sea coupling over western Arabian Sea cold filaments. J. Climate, 17 , 1213–1224.
Wang, B., , P. J. Webster, , and H. Teng, 2005: Antecedents and self-induction of active-break south Asian monsoon uraveled by satellites. Geophys. Res. Lett., 32 .L04704, doi:10.1029/2004GL020996.
Webster, P. J., , V. O. Magana, , T. N. Palmer, , J. Shukla, , R. A. Tomas, , M. Yanai, , and T. Yasunari, 1998: Monsoons: Processes, predictability and prospects for prediction. J. Geophys. Res., 103 , 14451–14510.
Webster, P. J., , A. M. Moore, , J. P. Loschnigg, , and R. R. Leben, 1999: Coupled ocean–atmosphere dynamics in the Indian Ocean during 1997–98. Nature, 401 , 356–360.
Xie, S. P., , H. Annamalai, , F. A. Schott, , and J. P. McCreary, 2002: Structure and mechanisms of South Indian Ocean climate variability. J. Climate, 15 , 864–878.
Yamagata, T., , S. K. Behera, , J-J. Luo, , S. Masson, , M. R. Jury, , and S. A. Rao, 2004: Coupled ocean–atmosphere variability in the tropical Indian Ocean. Earth Climate: The Ocean–Atmosphere Interaction,Geophys. Monogr., Vol. 147, Amer. Geophys. Union, 189–211.