# Multi-Temporal Sentinel-1 Backscatter and Coherence for Rainforest Mapping
## 4 Materials  
The study area covers an extended region over the state of Rondonia, Brazil (approximately 238 thousand km\({}^{2}\)), comprised between 7 deg50\({}^{\prime}\) and 13 deg50\({}^{\prime}\) latitude South and 59 deg50\({}^{\prime}\) and 67 deg10\({}^{\prime}\) longitude West. This area has become of primary interest, since it is one of the most deforested places in the Amazon basin. Furthermore, since the end of April 2019 the European Space Agency (ESA) has planned a 6-days repeat-pass coverage with the Sentinel-1a and Sentinel-1b satellites in order to monitor the state of the rainforest. Within this large study area, we downloaded and processed a set of 12 S-1 short-time-series in the framework explained in Figure 1, extracting for each stack the 22 feature maps described in Section 3. According to Section 3, interferometric stacks of five acquisitions, corresponding to an observation time of 30 days, were coregistered with respect to a master image, chosen as the one in the middle of the acquisitions. As presented in Figure 2 stacks belonging to a certain relative orbit have the same master date and all of these dates are centered around an average date, named acquisitions centroid. The provided 12 common swaths are described in Table 2 and further details can be found in Table 11, while the location of the 12 footprints, superimposed on Google Earth, are depicted in Figure 3. Here, the external reference map FROM-GLC (described in the following) is displayed. From a first visual inspection of Figure 3, some void areas can be identified along the orbit planes. These gaps are due to the misalignment in azimuth between S-1A and S-1B acquisitions and the stringent coregistration requirements for TOPS data. The varying squint (during the acquisition of a burst) causes a large variation of the Doppler centroid within the burst itself and a coregistration error results in a different phase ramp for different bursts, leading to consequently undesired phase jumps between subsequent bursts. In order to ensure a proper coregistration of the data, the enhanced spectral diversity (ESD) technique is applied to the overlapping areas between adjacent bursts [10; 22; 23]. This approach provides results with accuracy of few centimeters if the overlapping area is sufficiently extended. In correspondence of those gaps this constraint is unfortunately not respected and the interferometric results are therefore not trustworthy. For both training and validation we used a modified version of the Finer Resolution Observation and Monitoring of Global Land Cover (FROM-GLC) map [24]. This reference is a global land cover map generated using a Random Forests classifier, trained on Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) data and updated to 2017 using additional Sentinel-2 data. Since the FROM-GLC map comprises an inventory of 10 land cover classes, we first grouped them into four macro-classes: artificial surfaces (ART), forests (FOR), non-forested areas (NFR), and water bodies and unclassified or no data as invalids (INV), as shown in Table 3. Secondly, because of the difficulty in finding reliable reference data over the Amazon basin, we discarded all the possible temporal inconsistencies between FROM-GLC reference and Sentinel-1, by relying on the PRODES (Programa de Calculo do Desflorestamento da Amazonia) digital map [25]. PRODES is a ground polygon inventory derived from visual inspection of optical data and depicts new deforested areas on a yearly base. We therefore extracted from PRODES the polygons corresponding to new cuts occurred between 2017 and 2019 and we set them as invalid samples in the FROM-GLC map, obtaining a more reliable map that, for the sake of simplicity, we named REF. Figure 4 shows the external REF reference map (left), represented as the FROM-GLC 2017 of Figure 3 with in yellow the clearcuts (CUT) marked  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{7}{c}{**Corner Coordinates [deg]**} \\ \hline
**Stack** & **Orbit** & **Name** & **Lat.