Fig. 2: A solar cycle in olive pollen production.
From: Olive production in the 21st century will be threatened by water stress and declining solar activity
a Olive pollen influx (expressed in pollen grains per cm−2 per year−1) is drawn on a linear age scale (expressed in kiloyears Before Present) and shown with the standard deviation. The long-term trends are depicted as 200 years moving average and as a sinusoidal regression (with the 1σ error). The periods of low/high pollen production are highlighted by different colours. b Wavelet transform (scalogram) for the olive pollen influx is detailed. The cone of influence is denoted as a grey line, and the significance level (P = 0.05) is as white lines. The main periodicity is noted on the graph.
