Fig. 3From: The changing relationship between Cholera and interannual climate variables in Kolkata over the past centuryWavelet power spectrum depicting the strength of a particular wavelet scale across time for historical (a) and recent (b) epidemiological time signals. Color represents wavelet power level, where yellow regions indicate a strong contribution of a wavelet with a particular period at a particular date. The faded area denotes regions outside of the ‘cone of influence’ where the accuracy of the calculation is reduced by the presence of edge effects. Black outlines denote areas of statistical significance (p < 0.05) against the null hypothesis of white noiseBack to article page