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Stable water isotopes in HadCM3: isotopic signature of El Nino-Southern Oscillation and the tropical amount effect

Tindall, J. C.; Valdes, P.J.; Sime, Louise C.. 2009 Stable water isotopes in HadCM3: isotopic signature of El Nino-Southern Oscillation and the tropical amount effect. Journal of Geophysical Research, 114 (D4), D04111. 12, pp. 10.1029/2008JD010825

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Abstract/Summary

Stable water isotopes have been added to the full hydrological cycle of the Hadley Centre Climate model (HadCM3) coupled atmosphere-ocean GCM. Simulations of delta O-18 in precipitation and at the ocean surface compare well with observations for the present-day climate. The model has been used to investigate the isotopic anomalies associated with ENSO; it is found that the anomalous delta O-18 in precipitation is correlated with the anomalous precipitation amount in accordance with the "amount effect.'' The El Nino delta O-18 anomaly at the ocean surface is largest in coastal regions because of the mixing of ocean water and the more depleted runoff from the land surface. Coral delta O-18 anomalies were estimated, using an established empirical relationship, and generally reflect ocean surface delta O-18 anomalies in coastal regions and sea surface temperatures away from the coast. The spatial relationship between tropical precipitation and delta O-18 was investigated for the El Nino anomaly simulated by HadCM3. Weighting the El Nino precipitation anomaly by the precipitation amount at each grid box gave a large increase in the spatial correlation between tropical precipitation and delta O-18. This improvement was most apparent over land points and between 10 and 20 degrees of latitude.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1029/2008JD010825
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > Climate and Chemistry - Forcings and Phasings in the Earth System
ISSN: 0148-0227
NORA Subject Terms: Marine Sciences
Meteorology and Climatology
Glaciology
Hydrology
Atmospheric Sciences
Date made live: 12 Nov 2010 15:51
URI: http://nora.nerc.ac.uk/id/eprint/11323

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