Projet Imalirijiit/végétation

• Main Author: Dedieu, Jean-Pierre
• Other Authors: Univ. Grenoble Alpes, IRD, CNRS, INRAE, Grenoble INP*, IGE, 38000 Grenoble, France *Institute of Engineering and Management Univ. Grenoble Alpes (UMR IGE), ANR-11-LABX-0010,DRIIHM / IRDHEI,Dispositif de recherche interdisciplinaire sur les Interactions Hommes-Milieux(2011)
• Format: Conference Object
• Language: French
• Published: HAL CCSD 2021
• Subjects: OHMi Nunavik; [SDE]Environmental Sciences; Kangiqsualujjuaq; Tundra; Nunavik
• Online Access: https://hal.science/hal-04642085

National audience Analysis of greening dynamics in the George River watershed, Nunavik, using remote sensing Studies of vegetation dynamics at the circumpolar scale by spatial remote sensing showed a significant increase in plant productivity (“Shrubification”) over the past 30 years, associated with an increase in temperature. In the specific case of Nunavik, the Imalirijiit program conducted a study on this topic; the study was funded in part by the APR 2019-2020 from OHMI Nunavik. This study focused on two complementary components: (i) Analysis of the 30-year spatio-temporal evolution of plant activity within George River watershed (42,000 km2) comparing three key dates: 1985, 2000 and 2015.The normalized difference vegetation index (NDVI) has been applied to mosaics of summer Landsat images (resolution 30 m) and indicates that greening is not constant over the total period. There are differences in dynamics with four types of dominant responses related to latitude, altitude, and plant formations (either forest, shrub or tundra). (ii) Analysis of the possibilities of spatial remote sensing to map Ericaceae. These plant formations are essential for traditional feeding of communities because they produce berries; however they are threatened by the extension of shrubs. Their ground cover can be mapped by Sentinel-2 satellites with sufficient ground resolution (10 m) and the spectral band adapted to their detection (Red-Edge). The study focused on an area near Kangiqsualujjuaq with images from summer and autumn of 2019. The NARI specific index is used to map ericaceae, however field validations could not take place in 2020 due to the Covid-19 pandemic. Analyse des dynamiques de verdissement par télédétection dans le bassin versant de la Rivière George, Nunavik Les études portant sur les dynamiques de végétation réalisées à l’échelle circumpolaire par télédétection spatiale ont montré une nette augmentation de la productivité végétale (« verdissement ») sur les 30 dernières années, associée à une augmentation ...