# Satellite Monitoring of Italian Vineyards and Spatio-Temporal Variability Assessment
## 2 Materials and Methods
### Biomass Developing Evolution  
The biomass evolution in vineyards was determined based on RS on the web GIS Google Earth Engine (GEE). Multispectral imagery from the harmonized S2 (Level-2A) MultiSpectral Instrument (MSI) dataset includes a collection of images acquired by the S2 constellation, spanning from 2017 and available on GEE [34]. The analysis was carried out during the six-year grapevine development season from 2017 to 2022. This dataset has undergone a process of harmonisation wherein the digital number values of newer acquisitions have been adjusted by an increment of 1000, ensuring uniformity across the dataset (seamless) and thus making temporal comparisons more reliable. The imagery available in this dataset, sourced directly from the European Space Agency's (ESA) SciHub portal ([[https://scihub.copernicus.eu/](https://scihub.copernicus.eu/)]([https://scihub.copernicus.eu/](https://scihub.copernicus.eu/)), accessed on 1 November 2020), has been atmospherically corrected utilising the sen2 cor tool (Level-2A achieves bottom of atmosphere reflectance--BOA) and subsequently integrated into the Earth Engine database for enhanced accessibility and analysis. Cloud contamination was mitigated through a two-stage  
Figure 4: Grapevine’s training system classification: (**a**) vertical (VS), (**b**) horizontal (HS), (c) Alberello (AS). Figure 3: The structural features are displayed in (**a**). The purple polygon traces the field borders. The white and light blue lines mean the row’s length and the vineyard’s width, respectively, in correspondence to the vineyard’s centroid. The white dashed lines represent the two following rows in which the row spacing was measured. Finally, the yellow rectangular is the headland in which the headland’s width was appraised. The classification of the rows’ orientation is displayed in (**b**). The rows’ orientation ranged from 90\({}^{\circ}\) to 269\({}^{\circ}\). The yellow slices mean the EW orientation. The green slice is the SE orientation, the orange slice is the NS orientation, and the light blue slice is the SW orientation. filtration process applied to the harmonized S2 MSI dataset. Initially, images manifesting cloud coverage exceeding 20% of their total pixels were systematically excluded to ensure the reliability of the remaining dataset. Subsequently, for the retained imagery, cloud-affected pixels were identified and eliminated by leveraging the Scene Classification Layer (SCL) intrinsic to S2 Level-2A products. This systematic approach ensures the extraction of cloud-free observations, significantly enhancing the quality and usability of the dataset. Actually, no vineyard-satellite alignment or same day-time was guaranteed during the monitoring. However, the above-mentioned S2 peculiarities should ensure reliable ground data. Furthermore, comparing statistical indices instead of absolute values from each vineyard with a time series monitoring performed in the multi-season analysis should overcome any RS weaknesses. Two VIs were computed for each vineyard's pixel of every image. NDVI [35] and NDRE [36] were used for this study. The formulas of the VIs are described in Equations (1) and (2). For this purpose, the following S2 bands were selected: NIR (band 8), red (band 4), and vegetation red edge (band 5). Additional specifications are listed in Table 1. The revisit interval of S2 at the Italian latitude is five days. For this study, the monitoring lasted 60 days during the middle phase of the grapevine development, which is the most important period for biomass increase [37]. The vineyards that provided less than four satellite images per year were excluded from the analysis, as four points was the threshold for fitting linear regression. Regional information about grapevine phenological stages is available on the government institution \"Rete Rurale Nazionale\" assessed on www.reterurale.it (accessed on 1 June 2023). Hence, the flowering date (BBCH 65) of _Vitis vinifera_ cv. Chardonnay was chosen as a reference for each Italian political region.