Climate of the Past

An Interactive Open Access Journal of the European Geosciences Union

| Contact |
Volumes and Issues  Contents of Issue 5  Special Issue  
Clim. Past Discuss., 5, 2177-2222, 2009
www.clim-past-discuss.net/5/2177/2009/
doi:10.5194/cpd-5-2177-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.

A unified proxy for ENSO and PDO variability since 1650

S. McGregor, A. Timmermann, and O. Timm
IPRC, SOEST, University of Hawaii at Manoa, POST Bldg., Room 401, 1680 East-West Road, Honolulu, HI 96822, Hawaii, USA

Abstract. In this manuscript we have attempted to consolidate the common signal in previously defined proxy reconstructions of the El Niño-Southern Oscillation into one individual proxy titled the Unified ENSO Proxy (UEP). While correlating well with the majority of input reconstructions, the UEP provides better representation of observed indices of ENSO, discrete ENSO events and documented historical chronologies of ENSO than any of these input ENSO reconstructions. Further to this, the UEP also provides a means to reconstruct the PDO/IPO multi-decadal variability of the Pacific Ocean as the low-pass filtered UEP displays multi-decadal variability that is consistent with the 20th century variability of the PDO and IPO. The UEP is then used to describe changes in ENSO variability which have occurred since 1650 focusing on changes in ENSOs variance, multi-year ENSO events, PDO-like multi-decadal variability and the effects of volcanic and solar forcing on ENSO. We find that multi-year El Niño events similar to the 1990–1995 event have occurred several times over the last 3 1/2 centuries. Consistent with earlier studies we find that volcanic forcing can induce a statistically significant change in the mean state of ENSO in the year of the eruption and a doubling of the probability of an El Niño (La Niña) event occurring in the year of (three years after) the eruption.

Discussion Paper (PDF, 917 KB)   Interactive Discussion (Closed, 4 Comments)   Final Revised Paper (CP)   

Citation: McGregor, S., Timmermann, A., and Timm, O.: A unified proxy for ENSO and PDO variability since 1650, Clim. Past Discuss., 5, 2177-2222, doi:10.5194/cpd-5-2177-2009, 2009.   Bibtex   EndNote   Reference Manager    XML
 

Search CP


News

Recent Papers