Articles | Volume 6
Adv. Geosci., 6, 29–33, 2006
https://doi.org/10.5194/adgeo-6-29-2006
Adv. Geosci., 6, 29–33, 2006
https://doi.org/10.5194/adgeo-6-29-2006

  09 Jan 2006

09 Jan 2006

Coupled model simulations of mid-Holocene ENSO and comparisons with coral oxygen isotope records

J. Brown1, M. Collins2, and A. Tudhope3 J. Brown et al.
  • 1Centre for Global Atmospheric Modelling, Department of Meteorology, University of Reading, Reading, UK
  • 2Hadley Centre for Climate Prediction and Research, Met Office, Exeter, UK
  • 3School of Geosciences, University of Edinburgh, Edinburgh, UK

Abstract. The sensitivity of El Niño-Southern Oscillation (ENSO) to changes in mean climate is investigated for simulations of pre-industrial and mid-Holocene (6000 years before present) climate using the Hadley Centre coupled atmosphere-ocean model, HadCM3. Orbitally-forced changes in insolation in the mid-Holocene produce changes in seasonality which may alter ENSO amplitude and frequency. The model simulations are compared with mid-Holocene fossil coral oxygen isotope records from the western Pacific Warm Pool. The coral records imply a reduction of around 60% in the amplitude of interannual variability associated with ENSO in the mid-Holocene, while the model simulates a smaller reduction in ENSO amplitude of around 10%. The model also simulates a slight shift to longer period variability and a weakening of ENSO phase-locking to the seasonal cycle in the mid-Holocene. There is little change in the pattern of ENSO tropical precipitation teleconnections in the simulated mid-Holocene climate.

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