Harrison and Larkin, 1997: Darwin sea level pressure, 1876-1996: evidence for climate change?
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last modified
Mar 25, 2009 02:01 PM
published in Geophysical Research Letters
Reference
Harrison, D.E., and N.K. Larkin, 1997. Darwin seal level pressure 1876-1996: evidence for climate change? GRL, 24 (14), 1779-1782.
Abstract
It has been argued that there was a period of prolonged ENSO conditions between 1990-95 so anomalous that it is "highly unlikely" to be due to "natural decadal-timescale variation" [Trenberth and Hoar, 1996]. This conclusion follows from their study of the Darwin sea level pressure anomaly record, which foudn that the 1990-95 period would occur randomly about once every 1100-3000 yrs. Taking into account the uncertainty in the number of degrees of freedom in the Darwin time series, we find that conditions like those of 1990-95 may be expected as often as every 150-200 yrs at the 95% confidence level. Student's-t,ARMA, and Bootstrap/Monte Carlo test of the time series all yeild similar results. We therefore suggest that the 1990-95 peiod may plausibly be an aspect of the natural variability of the tropical Pacific.
