AVHRR NDVI Compositing Method Comparison and Generation of Multi-Decadal Time Series—A TIMELINE Thematic Processor

Remote sensing image composites are crucial for a wide range of remote applications, such as multi-decadal time series analysis. The Advanced Very High Resolution Radiometer (AVHRR) instrument has provided daily data since the early 1980s at spatial resolution 1 km, allowing analyses climate change-related environmental processes. For monitoring vegetation conditions, Normalized Difference Vegetation Index (NDVI) is most widely used metric. However, to actually enable analyses, consistent NDVI over AVHRR time-span needs be created. In this context, aim study thoroughly assess effect different compositing procedures on composites, no standard procedure been established. Thirteen methods have implemented; daily, decadal, and monthly Europe Northern Africa calculated year 2007, resulting sets evaluated according six criteria. median approach was selected best-performing algorithm considering all investigated aspects. combination value viewing illumination angles criteria best-pixel selection proved promising approach, too. generated series, currently ranging from 1981–2018, shows behavior close agreement MODIS product. conducted demonstrate strong influence composites.