*2.1. Materials*

For this study, we downloaded MODIS data from the MOD09 product [20,21] from 2000–2015 and AVHRR from the LTDR product [22]. We divided the data into AVHRR-pre MODIS (1982-2000) and AVHRR (2000–2015). These data contain surface reflectance at Climate Modelling Grid (CMG) spatial resolution (0.05◦). We use the red and NIR surface reflectance bands, as well as the view zenith (*θv*), solar zenith (*θs*), and relative azimuth (*φ*) angles, selecting pixels of the highest quality. We extracted the data for individual pixels in the 445 Benchmark Land Multisite Analysis and Intercomparison of Products (BELMANIP2) sites. BELMANIP2 sites are an update of BELMANIP1 [23] and were selected due to their representativeness and variability of vegetation types and climatological conditions around the world. Moreover, they were selected so that the sites are homogeneous over a 10 × 10 km<sup>2</sup> area, so these sites are homogeneous at CMG resolution (0.05◦ or 5.6 km). We obtained the NDVI from the red and NIR bands from AVHRR-pre, AVHRR and MODIS data. The product includes no spectral adjustment method, which is necessary considering that the time series is composed of data from several different National Oceanic and Atmospheric Administration (NOAA) satellites. Moreover, an accurate intercomparison with MODIS requires that all data be on the same radiometric scale. For this reason, we perform spectral adjustment using methods from Reference [24], selecting NOAA14 as a reference.
