Figure 2.

Duration, timing, and height of annual peaks of telemetrically measured variables and NDVI. Sections separated by vertical lines indicate periods with different light and vegetation conditions, i.e. the period when the sun was continuously below the horizon (Polar Night, DD), the periods with daylight and night (LD), the period of continual light (Midnight Sun, LL) before the onset of the vegetation period with NDVI values <0 (LL low), and the period of continual light with above-ground new vascular plant growth (NDVI >0, LL high). Plotted are baseline cosine fits to empirical data shown in Fig. 1, and their 95% confidence intervals (for details see Methods).