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

JC Tindall, PJ Valdes, L.C. Sime

Research output: Contribution to journalArticle (Academic Journal)peer-review

112 Citations (Scopus)

Abstract

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.
Translated title of the contributionStable water isotopes in HadCM3: Isotopic signature of El Nino Southern Oscillation and the tropical amount effect
Original languageEnglish
Article numberD04111
JournalJournal of Geophysical Research: Atmospheres
Volume114
Publication statusPublished - Feb 2009

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