Dynamical Contribution to Hemispheric Temperature Trends

John M. Wallace, Yuan Zhang and James A. Renwick

In press, Science, September 1995.

Abstract

Roughly half the temporal variance of monthly-mean (Northern) hemispheric- mean surface air temperature anomalies based on land station data is shown to be linearly related to the amplitude of a distinctive spatial pattern in which the oceans are anomalously cold and the continents anomalously warm poleward of 40° N when the hemisphere is warm. Apart from an upward trend since 1975 , to which El Niño has contributed, the amplitude time series associated with this pattern resembles seasonally dependent white noise. We argue that the variability associated with this pattern is dynamically induced and not necessarily an integral part of the fingerprint of global warming.

Compressed tar file (.5 Mbytes) containing PostScript files of the manuscript and figures.

Corresponding author: Yuan Zhang (zhang@atmos.washington.edu)

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