**3. Results**

## *3.1. Seasonal Evolution and Correlations*

The temporal evolution of the ET and the monthly ECI with reference to the snow cover information is shown in Figure 3. For the Renon, Lavarone and Monte Bondone study area, both the ET and ECI seem to follow the same seasonal evolution, particularly in the summer months, when both the curves reaches the peak. In several situations, generally in the cold months, the ECI behaves differently, creating a "second peak" that does not follow the normal ET trend. The snow cover information explains the "winter peak" of the ECI, where the amplitude and the size of both the blue curve and black histogram are indeed similar. On the other hand, in the Bosco della Fontana study area, ET and the ECI have an opposite seasonal evolution. ET has a normal seasonal trend with the highest values in summer, decreasing in winter, whereas the ECI has its low values in summer.

**Figure 3.** Relationship between the ET (ET tower—blue line) and the monthly ECI (red line).

Figure 4 shows the linear regression between ET-ECI considering the months with low snow cover (lower than 50%). This was carried out to assess the strength of the correlation without the "anomalous peaks" created by the ECI in the cold months. In the Renon, Lavarone and Monte Bondone study areas, the correlations are all positive, reaching an *R*<sup>2</sup> between 0.49 (Lavarone) to 0.68 (Renon). In the Bosco della Fontana study area, the correlation is negative, reaching an *R*<sup>2</sup> of 0.72.

The monthly time series of ET and the WDI are shown in Figure 5. In the four study areas, both the curves show the same trend, with the peak in the summer months and a lower value in winter.

Figure 6 shows the linear regression between ET and the WDI for the four considered study areas. *R*<sup>2</sup> ranges from 0.48 (Lavarone) to 0.89 (Bosco della Fontana). Unlike the correlation ET-ECI, the slope remains positive for all of the considered areas.

**Figure 4.** Linear regression between the ET (ET tower) and the monthly ECI when the snow cover is lower than 50%. *N* is the number of data points.

**Figure 5.** Time series of ET (blue dashed line) and WDI (red line)

**Figure 6.** Linear regression between ET and WDI for the four considered study areas.
