Upper-Ocean Salinity Variability in the Tropical Pacific: Case Study for Quasi-Decadal Shift during the 2000s Using TRITON Buoys and Argo Floats

Takuya Hasegawa Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan

Search for other papers by Takuya Hasegawa in
Current site
Google Scholar
PubMed
Close
,
Kentaro Ando Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan

Search for other papers by Kentaro Ando in
Current site
Google Scholar
PubMed
Close
,
Iwao Ueki Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan

Search for other papers by Iwao Ueki in
Current site
Google Scholar
PubMed
Close
,
Keisuke Mizuno Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan

Search for other papers by Keisuke Mizuno in
Current site
Google Scholar
PubMed
Close
, and
Shigeki Hosoda Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan

Search for other papers by Shigeki Hosoda in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Upper-ocean salinity variation in the tropical Pacific is investigated during the 2000s, when Triangle Trans-Ocean Buoy Network (TRITON) buoys and Argo floats were deployed and more salinity data were observed than in previous periods. This study focuses on upper-ocean salinity variability during the warming period of El Niño–Southern Oscillation (ENSO)-like quasi-decadal (QD)-scale sea surface temperature anomalies over the central equatorial Pacific (January 2002–December 2005; hereafter “warm QD phase”). It is shown that strong negative salinity anomalies occur in the western tropical Pacific and the off-equatorial Pacific in the upper ocean at depths less than 80 m, showing a horseshoe-like pattern centered at the western tropical Pacific during the warm QD phase. TRITON mooring buoy data in the western equatorial Pacific show that low-salinity and high-temperature water could be transported eastward from the western equatorial Pacific to the central equatorial Pacific during the warm QD phase. Similar patterns, but with the opposite sign of salinity anomalies, appear in the cold QD phase during January 2007–December 2009 with negative sea surface temperature anomalies over the central equatorial Pacific. It is suggested that effects from zonal salinity advection and precipitation could contribute to the generation of the salinity variations in the western equatorial Pacific for QD phases during the 2000s. On the other hand, the contribution of meridional salinity advection is much less than that of zonal salinity advection. In addition, El Niño Modoki and La Niña events could affect salinity changes for warm and cold QD phases via interannual-scale zonal salinity advection variations in the western equatorial Pacific during the 2000s.

Corresponding author address: Takuya Hasegawa, Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-Cho, Yokosuka, Kanagawa 237-0061, Japan. E-mail: takuyah@jamstec.go.jp

Abstract

Upper-ocean salinity variation in the tropical Pacific is investigated during the 2000s, when Triangle Trans-Ocean Buoy Network (TRITON) buoys and Argo floats were deployed and more salinity data were observed than in previous periods. This study focuses on upper-ocean salinity variability during the warming period of El Niño–Southern Oscillation (ENSO)-like quasi-decadal (QD)-scale sea surface temperature anomalies over the central equatorial Pacific (January 2002–December 2005; hereafter “warm QD phase”). It is shown that strong negative salinity anomalies occur in the western tropical Pacific and the off-equatorial Pacific in the upper ocean at depths less than 80 m, showing a horseshoe-like pattern centered at the western tropical Pacific during the warm QD phase. TRITON mooring buoy data in the western equatorial Pacific show that low-salinity and high-temperature water could be transported eastward from the western equatorial Pacific to the central equatorial Pacific during the warm QD phase. Similar patterns, but with the opposite sign of salinity anomalies, appear in the cold QD phase during January 2007–December 2009 with negative sea surface temperature anomalies over the central equatorial Pacific. It is suggested that effects from zonal salinity advection and precipitation could contribute to the generation of the salinity variations in the western equatorial Pacific for QD phases during the 2000s. On the other hand, the contribution of meridional salinity advection is much less than that of zonal salinity advection. In addition, El Niño Modoki and La Niña events could affect salinity changes for warm and cold QD phases via interannual-scale zonal salinity advection variations in the western equatorial Pacific during the 2000s.

Corresponding author address: Takuya Hasegawa, Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-Cho, Yokosuka, Kanagawa 237-0061, Japan. E-mail: takuyah@jamstec.go.jp
Save
  • Alory, G., C. Maes, T. Delcroix, N. Reul, and S. Ilig, 2012: Seasonal dynamics of sea surface salinity off Panama: The far eastern Pacific fresh pool. J. Geophys. Res., 117, C04028doi:10.1029/2011JC007802.

    • Search Google Scholar
    • Export Citation
  • Ando, K., and M. J. McPhaden, 1997: Variability of surface layer hydrography in the tropical Pacific Ocean. J. Geophys. Res., 102 (C10), 23 06323 078.

    • Search Google Scholar
    • Export Citation
  • Ando, K., T. Matsumoto, T. Nagahama, I. Ueki, Y. Takatsuki, and Y. Kuroda, 2005: Drift characteristics of a moored conductive–temperature–depth sensor and correction salinity data. J. Atmos. Oceanic Technol., 22, 282291.

    • Search Google Scholar
    • Export Citation
  • Argo Science Team, 2000: Report of the Argo Science Team second meeting. Proc. Argo. Science Team Second Meeting, Southampton, United Kingdom, Southampton Oceanography Centre, 1–35.

  • Ashok, K., S. K. Behera, S. A. Rao, H. Weng, and T. Yamagata, 2007: El Niño Modoki and its possible teleconnection. J. Geophys. Res., 112, C11007, doi:10.1029/2006JC003798.

    • Search Google Scholar
    • Export Citation
  • Bonjean, F., and G. S. E. Lagerloef, 2002: Diagnostic model and analysis of the surface currents in the tropical Pacific Ocean. J. Phys. Oceanogr., 32, 29382954.

    • Search Google Scholar
    • Export Citation
  • Bosc, C., T. Delecroix, and C. Maes, 2009: Barrier layer variability in the western Pacific warm pool from 2000 to 2007. J. Geophys. Res., 114, C06023, doi:10.1029/2998JC005187.

    • Search Google Scholar
    • Export Citation
  • Cravatte, S., T. Delcroix, D. Zhang, M. McPhaden, and J. Leloup, 2009: Observed freshening and warming of the western Pacific warm pool. Climate Dyn., 33, 565589, doi:10.1007/s00382-009-0526-7.

    • Search Google Scholar
    • Export Citation
  • Davis, R. E., W. S. Kessler, and J. T. Sherman, 2012: Gliders measure western boundary current transport from the South Pacific to the equator. J. Phys. Oceanogr., 42, 20012013.

    • Search Google Scholar
    • Export Citation
  • Delcroix, T., and J. Picaut, 1998: Zonal displacement of the western equatorial Pacific “fresh pool.” J. Geophys. Res., 103 (C1), 10871098.

    • Search Google Scholar
    • Export Citation
  • Delcroix, T., S. Cravatte, and M. J. McPhaden, 2007: Decadal variations and trends in tropical Pacific sea surface salinity since 1970. J. Geophys. Res., 112, C03012, doi:10.1029/2006JC003801.

    • Search Google Scholar
    • Export Citation
  • Hase, H., and Y. Kuroda, 2002: Validation of TRITON buoy current meter performance (in Japanese). Rep. Japan Mar. Sci. Technol. Cent., 45, 5562.

    • Search Google Scholar
    • Export Citation
  • Hasegawa, T., and K. Hanawa, 2003: Decadal-scale variability of upper ocean heat content in the tropical Pacific. Geophys. Res. Lett., 30, 1272, doi:10.1029/2002GL016843.

    • Search Google Scholar
    • Export Citation
  • Hasegawa, T., T. Yasuda, and K. Hanawa, 2007: Generation mechanism of quasidecadal variability of upper ocean heat content in the equatorial Pacific Ocean. J. Geophys. Res., 112, C08012, doi:10.1029/2006JC003755.

    • Search Google Scholar
    • Export Citation
  • Hasegawa, T., K. Ando, K. Mizuno, and R. Lukas, 2009: Coastal upwelling along the north coast of Papua New Guinea and SST cooling over the Pacific warm pool: A case study for the 2002/03 El Niño event. J. Oceanogr., 65, 803817.

    • Search Google Scholar
    • Export Citation
  • Hénin, C., Y. du Penhoat, and M. Ioualalen, 1998: Observations of sea surface salinity in the western Pacific fresh pool: Large-scale changes in 1992–1995. J. Geophys. Res., 103 (C4), 75237536.

    • Search Google Scholar
    • Export Citation
  • Hosoda, S., T. Ohira, and T. Nakamura, 2008: A monthly mean dataset of global oceanic temperature and salinity derived from Argo flat observations. JAMSTEC Rep. Res. Dev., 8, 4759.

    • Search Google Scholar
    • Export Citation
  • Hosoda, S., T. Suga, N. Shikama, and K. Mizuno, 2009: Global surface layer salinity change detected by Argo and its implication for hydrological cycle intensification. J. Oceanogr., 65, 579586.

    • Search Google Scholar
    • Export Citation
  • Huffman, G. J., and Coauthors, 2007: The TRMM Multisatellite Precipitation Analysis (TMPA): Quasi-global, multiyear, combined-sensor precipitation estimates at fine scale. J. Hydrometeor., 8, 3855.

    • Search Google Scholar
    • Export Citation
  • Johnson, E. S., F. Bonjean, G. S. E. Lagerloaf, and J. T. Gunn, 2007: Validation and error analysis of OSCAR sea surface currents. J. Atmos. Oceanic Technol., 24, 688701.

    • Search Google Scholar
    • Export Citation
  • Kao, H.-Y., and J.-Y. Yu, 2009: Contrasting eastern-Pacific and central-Pacific types of ENSO. J. Climate, 22, 615632.

  • Kashino, Y., I. Ueki, Y. Kuroda, and A. Purwandani, 2007: Ocean variability north of New Guinea derived by TRITON buoy data. J. Oceanogr., 63, 554559.

    • Search Google Scholar
    • Export Citation
  • Kerr, Y., P. Waldteufel, J. P. Wigneron, J. M. Martinuzzi, J. Font, and M. Berger, 2001: Soil moisture retrieval from space: The Soil Moisture and Ocean Salinity (SMOS) mission. IEEE Trans. Geosci. Remote Sens., 39, 17291735, doi:10.1109/36.942551.

    • Search Google Scholar
    • Export Citation
  • Kug, J.-S., F.-F. Jin, and S.-I. An, 2009: Two types of El Niño events: Cold tongue El Niño and warm pool El Niño. J. Climate, 22, 14991515.

    • Search Google Scholar
    • Export Citation
  • Lagerloef, G., and Coauthors, 2008: The Aquarius/SAC-D mission: Designed to meet the salinity remove-sensing challenge. Oceanography, 21, 6881.

    • Search Google Scholar
    • Export Citation
  • Larkin, N. K., and D. E. Harrison, 2005: On the definition of El Niño and associated seasonal average U.S. weather anomalies. Geophys. Res. Lett., 32, L13705, doi:10.1029/2005GL022738.

    • Search Google Scholar
    • Export Citation
  • Lukas, R., and E. Lindstrom, 1991: The mixed layer of the western equatorial Pacific Ocean. J. Geophys. Res., 96 (Suppl.), 33433357.

  • Luo, J., and T. Yamagata, 2001: Long-term El Niño–Southern Oscillation (ENSO)-like variation with special emphasis on the South Pacific. J. Geophys. Res., 106 (C10), 22 21122 227.

    • Search Google Scholar
    • Export Citation
  • Luo, J., S. Masson, S. Behera, P. Delecluse, S. Gualdi, A. Navarra, and T. Yamagata, 2003: South Pacific origin of the decadal ENSO-like variation as simulated by a coupled GCM. Geophys. Res. Lett., 30, 2250, doi:10.1029/2003GL018649.

    • Search Google Scholar
    • Export Citation
  • Maes, C., J. Picaut, and S. Belamari, 2002: Salinity barrier layer and onset of El Niño in a Pacific coupled model. Geophys. Res. Lett.,29, 2206, doi;10.1029/2002GL016029.

  • Maes, C., J. Picaut, and S. Belamari, 2005: Importance of salinity barrier layer for the buildup of El Niño. J. Climate, 18, 104118.

    • Search Google Scholar
    • Export Citation
  • Maes, C., K. Ando, T. Delcroix, W. S. Kessler, M. J. McPhaden, and D. Roemmich, 2006: Observed correlation of surface salinity, temperature and barrier layer at the eastern edge of the western Pacific warm pool. Geophys. Res. Lett., 33, L06601, doi:10.1029/2005GL024772.

    • Search Google Scholar
    • Export Citation
  • Mantua, N. J., S. R. Hare, Y. Zhang, J. M. Wallace, and R. C. Francis, 1997: A Pacific interdecadal climate oscillation with impacts on salmon production. Bull. Amer. Meteor. Soc., 78, 10691079.

    • Search Google Scholar
    • Export Citation
  • McPhaden, M. J., S. E. Zebiak, and M. H. Glantz, 2006: ENSO as an integrating concept in Earth science. Science, 314, 17401745.

  • McPhaden, M. J., and Coauthors, 2009: The global tropical moored buoy array. Proc. OceanObs'09: Sustained Ocean Observations and Information for Society Conf., Venice, Italy, ESA, Publ. WPP-306. [Available online at http://www.oceanobs09.net/proceedings/cwp/cwp61/index.php.]

  • Minobe, S., 1997: A 50–70 year climatic oscillation over the North Pacific and North America. Geophys. Res. Lett., 24, 683684.

  • Minobe, S., 1999: Resonance in bidecadal and pentadecadal climate oscillations over the North Pacific: Role in climate regime shifts. Geophys. Res. Lett., 26, 855858.

    • Search Google Scholar
    • Export Citation
  • Picaut, J., M. Ioualalen, C. Menkes, T. Delcroix, and M. J. McPhaden, 1996: Mechanism of the zonal displacements of the Pacific warm pool, implications for ENSO. Science, 277, 14861489.

    • Search Google Scholar
    • Export Citation
  • Picaut, J., F. Masia, and Y. du Penhoar, 1997: An advective-reflective conceptual model for the oscillatory nature of the ENSO. Science, 277, 663666.

    • Search Google Scholar
    • Export Citation
  • Picaut, J., M. Ioualalen, T. Delcroix, F. Masia, R. Murtugudde, and J. Vialard, 2001: The oceanic zone of convergence on the eastern edge of the Pacific warm pool: A synthesis of results and implications for ENSO and biogeochemical phenomena. J. Geophys. Res., 106 (C2), 23632386.

    • Search Google Scholar
    • Export Citation
  • Sasaki, Y. N., N. Schneider, N. Maximenko, and K. Lebedev, 2010: Observational evidence for propagation of decadal spiciness anomalies in the North Pacific. Geophys. Res. Lett., 37, L07708, doi:10.1029/2010GL042716.

    • Search Google Scholar
    • Export Citation
  • Schneider, N., 2000: A decadal spiciness mode in the tropics. Geophys. Res. Lett., 27, 257260.

  • Schneider, N., 2004: The response of tropical climate to the equatorial emergence of spiciness anomalies. J. Climate, 17, 10831095.

  • Singh, A., and T. Delcroix, 2011: Estimating the effects of ENSO upon the observed freshening trends of the western tropical Pacific Ocean. Geophys. Res. Lett., 38, L21607, doi:10.1029/2011GL049636.

    • Search Google Scholar
    • Export Citation
  • Singh, A., T. Delcroix, and S. Cravatte, 2011: Contrasting the flavors of El Niño–Southern Oscillation using sea surface salinity observations. J. Geophys. Res., 116, C06016, doi:10.1029/2010JC006862.

    • Search Google Scholar
    • Export Citation
  • Smith, T. M., R. W. Reynolds, T. C. Peterson, and J. Lawrimore, 2008: Improvements to NOAA's historical merged land–ocean surface temperature analysis (1880–2006). J. Climate, 21, 22832296.

    • Search Google Scholar
    • Export Citation
  • Tourre, Y. M., B. Rajagopalan, Y. Kushnir, M. Barlow, and W. B. White, 2001: Patterns of coherent decadal and interdecadal climate signals in the Pacific basin during the 20th century. Geophys. Res. Lett., 28, 20692072.

    • Search Google Scholar
    • Export Citation
  • Tourre, Y. M., C. Cibot, L. Terray, W. B. White, and B. Dewitte, 2005: Quasi-decadal and inter-decadal climate fluctuations in the Pacific Ocean from a GCM. Geophys. Res. Lett., 32, L07710, doi:10.1029/2004GL022087.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., 1997: The definition of El Niño. Bull. Amer. Meteor. Soc., 78, 27712777.

  • White, W. B., Y. M. Tourre, M. Barlow, and M. Dettinger, 2003: A delayed action oscillator shared by biennial, interannual, and decadal signals in the Pacific basin. J. Geophys. Res., 108, 3070, doi:10.1029/2002JC001490.

    • Search Google Scholar
    • Export Citation
  • Zhang, T. Y., J. M. Wallace, and D. S. Battisti, 1997: ENSO-like interdecadal variability: 1900–93. J. Climate, 10, 10041020.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 285 86 7
PDF Downloads 155 71 4