Comment on 'Influence of the Southern Oscillation on tropospheric temperature' by J. D. McLean,C. R. de Freitas, and R. M. Carter

摘要

[1] McLean et al. (2009) (henceforth MFC09) claim that the El Nino-SouthernOscillation (ENSO), as represented by the Southern Oscillation Index (SOI), accountsfor as much as 72% of the global tropospheric temperature anomaly and an even higher81% of this anomaly in the tropics. They conclude that the SOI is a "dominant andconsistent influence on mean global temperatures," "and perhaps recent trends in global'temperatures." However, their analysis is inappropriate in a number of ways and overstatesthe influence of ENSO on the climate system. This comment first briefly reviews what isunderstood about the influence of ENSO on global temperatures and then shows thatthe analysis of MFC09 greatly overestimates the correlation between temperatureanomalies and the SOI by inflating the power in the 2-6 year time window while filteringout variability on longer and shorter time scales. The suggestion in their conclusionsthat ENSO may be a major contributor to recent trends in global temperature is notsupported by their analysis or any physical theory presented in their paper, especially asthe analysis method itself eliminates the influence of trends on the purported correlations.