Climate Dynamics

, Volume 25, Issue 7–8, pp 777–800

A multi-model analysis of the role of the ocean on the African and Indian monsoon during the mid-Holocene

  • Y. Zhao
  • P. Braconnot
  • O. Marti
  • S.P. Harrison
  • C. Hewitt
  • A. Kitoh
  • Z. Liu
  • U. Mikolajewicz
  • B. Otto-Bliesner
  • S.L. Weber
Article

Abstract

We investigate the role of the ocean feedback on the climate in response to insolation forcing during the mid-Holocene (6,000 year BP) using results from seven coupled ocean–atmosphere general circulation models. We examine how the dipole in late summer sea-surface temperature (SST) anomalies in the tropical Atlantic increases the length of the African monsoon, how this dipole structure is created and maintained, and how the late summer SST warming in the northwest Indian Ocean affects the monsoon retreat in this sector. Similar mechanisms are found in all of the models, including a strong wind evaporation feedback and changes in the mixed layer depth that enhance the insolation forcing, as well as increased Ekman transport in the Atlantic that sharpens the Atlantic dipole pattern. We also consider changes in interannual variability over West Africa and the Indian Ocean. The teleconnection between variations in SST and Sahelian precipitation favor a larger impact of the Atlantic dipole mode in this region. In the Indian Ocean, the strengthening of the Indian dipole structure in autumn has a damping effect on the Indian dipole mode at the interannual time scale.

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Y. Zhao
    • 1
  • P. Braconnot
    • 1
  • O. Marti
    • 1
  • S.P. Harrison
    • 2
  • C. Hewitt
    • 3
  • A. Kitoh
    • 4
  • Z. Liu
    • 5
  • U. Mikolajewicz
    • 6
  • B. Otto-Bliesner
    • 7
  • S.L. Weber
    • 8
  1. 1.IPSL/Laboratoire de Sciences du climat et de l’environnementUnité mixte CEA-CNRSGif-sur-YvetteFrance
  2. 2.School of Geographical SciencesUniversity of BristolBristolUK
  3. 3.Hadley Centre Met OfficeExeterUK
  4. 4.Meteorological Research InstituteTsukubaJapan
  5. 5.University of Wisconsin-MadisonMadisonUSA
  6. 6.Max Planck Institute für MeteorologyHamburgGermany
  7. 7.Climate Change ResearchNational Center for Atmospheric ResearchBoulderUSA
  8. 8.Royal Netherlands Meteorological InstituteDe BiltThe Netherlands

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