NDVI or PPI: A (Quick) Comparison for Vegetation Dynamics Monitoring in Mountainous Area

Article Article scientifique Article NDVI or PPI: A (Quick) Comparison for Vegetation Dynamics Monitoring in Mountainous Area eng 2024 2024 author Charrière Dimitri Pablo 960705 author Francon Loïc 932400 author Giuliani Gregory 0000-0002-1825-8865 94488 Services communs de l'Institut des sciences de l'environnement (ISECO) 3894 10.3390/rs16203894 1104-3792 Cold ecosystems are experiencing a warming rate that is twice as fast as the global average and are particularly vulnerable to the consequences of climate change. In mountain ecosystems, it is particularly important to monitor vegetation to understand ecosystem dynamics, biodiversity conservation, and the resilience of these fragile ecosystems to global change. Hence, we used satellite data acquired by Sentinel-2 to perform a comparative assessment of the Normalized Difference Vegetation Index (NDVI) and the Plant Phenology Index (PPI) in mountainous regions (canton of Valais-Switzerland in the European Alps) for monitoring vegetation dynamics of four types: deciduous trees, coniferous trees, grasslands, and shrublands. Results indicate that the NDVI is particularly noisy in the seasonal cycle at the beginning/end of the snow season and for coniferous trees, which is consistent with its known snow sensitivity issue and difficulties in retrieving signal variation in dense and evergreen vegetation. The PPI seems to deal with these problems but tends to overestimate peak values, which could be attributed to its logarithmic formula and derived high sensitivity to variations in near-infrared (NIR) and red reflectance during the peak growing season. Concerning seasonal parameters retrieval, we find close concordance in the results for the start of season (SOS) and end of season (EOS) between indices, except for coniferous trees. Peak of season (POS) results exhibit important differences between the indices. Our findings suggest that PPI is a robust remote sensed index for vegetation monitoring in seasonal snow-covered and complex mountain environments. NDVI PPI Grassland Shrubland Mountains Sentinel-2 Phenology Dewey 333.7-333.9 18 Institut des sciences de l'environnement 0DB false 1057 TIGERS 941 ISE Pôle Informatique environnementale 938 ISE Pôle Sciences 673 Envirospace Lab 859 Global Resource Information Database (GRID) 970b71ee-b344-4440-bc52-c9af263975d0 Living Earth Lab Remote sensing 16 322331ac-23c7-4577-94c6-6072ccdb8b63 Article (Published version) Public remotesensing-16-03894.pdf 9221296 application/pdf CC BY-4.0 89803965931a5b3bacc934f01620788d445af407d5724e22cf0bb24ceb15eb55 openAccess Centres et instituts / Institut des sciences de l'environnement

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NDVI or PPI: A (Quick) Comparison for Vegetation Dynamics Monitoring in Mountainous Area	Remote sensing			2024	102	50

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Charrière, Dimitri Pablo

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