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Stern H, Moodie N, Cornall-Reilly J, Forster T, and McBride P (2005) Comment on A long-term trend in Melbourne rainfall?Bulletin of the Australian Meteorological and Oceanographic Society, Vol. 18.

Visual examination of a graph depicting the year-to-year fluctuations in annual Melbourne rainfall (1856-2003) suggests that there is no long-term trend. This is confirmed by statistical analysis of the data. The equation for the linear trend line is: Rain = 852.395 - 0.103*Year

There are 147 degrees of freedom yielding a t(-0.103) of -0.412. From this information one determines that the probability of the absolute value of t being =< .412 is 32%. This means that the probability of there being no long-term trend is 68%, that is, it is more than twice as likely (than not) that there is no long-term trend. Visual examination of a graph depicting the year-to-year fluctuations in annual Melbourne rainfall (1974-2003) suggests that thereannual may be a short-term trend.This is also confirmed by statistical analysis of the data. The equation for the linear trend line is: Rain = 6470.482 2.936*Year

There are 29 degrees of freedom yielding a t(-2.936) = -1.033. From this information one determines that the probability of the absolute value of t being =< 1.033 is 69%. This means that the probability of there being no short-term trend is 31%, that is, it is more than twice as likely (than not) that there is a short-term trend. With the probability of t being =<-1.033 at 16%, it is likely that the short-term trend is downward.

Home Publications Presentations Climate of Victoria 10 Day Forecasts Seasonal Outlook Other Links