Page:Hunt - The climate and weather of Australia - 1913.djvu/30

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GRAPHS SHEWING ANNUAL FLUCTUATIONS OF MEAN BAROMETRIC PRESSURE FOR THE STATE CAPITAL CITIES.


Explanation of the Graphs of Barometric Pressure.—On the above graphs the lines representing the yearly fluctuation of barometric pressure at the State capital cities are means for long periods, and are plotted from the Climatological Tables given hereinafter. The pressures are shewn in inches on about 2⅛ times the natural scale, and the corresponding pressures in centimetres are also shewn in the two inner columns, in which each division represents one millimetre.

Interpretation of the Barometric Graphs.—Taking the Brisbane graph for purposes of illustration, it will be seen that the mean pressure on 1st January is about 29.88 inches, and there are maxima in the middle of May and August of about 30.10 and 30.08 respectively. The double maxima appear clearly on each graph.

Fig. 28.



MEAN PRESSURE, APRIL, 1910.