Summary:
Published in Journal of Geophysical Research: Atmospheres 130(20): e2025JD044311
This study focuses on the net radiative forcing caused by the impoundment of an 85-km2 hydroelectric reservoir in the subarctic Côte-Nord, Quebec, Canada (50.69°N, 63.24°W, mean depth of 44 m). Using spectral bands from the Landsat 7 ETM+ and Landsat 8 OLI/TIRS satellites, we observed spatial and temporal variations in albedo and surface temperature on 104 dates between 2000 and 2023. By integrating these data with ERA5-Land meteorological reanalyses and in situ measurements, we investigated seasonal and interannual variations in shortwave and longwave radiative fluxes and net radiation before (2000–2013) and after (2015–2023) reservoir impoundment. The flooded area initially consisted of 79% coniferous forest (mainly black spruce), 15% water, 4% dry soil, and 2% wet soil. Before the impoundment, the average winter albedo was 0.25 ± 0.02 and the summer albedo was 0.08 ± 0.002. After the impoundment, the winter albedo increased significantly, reaching between 0.70 and 0.90 in the presence of fresh snow on the ice (January to May), while in summer it decreased to about 0.05 ± 0.003. Surface temperatures exhibited pronounced pre- to postimpoundment contrasts, with the reservoir consistently 2–7°C warmer in autumn and winter but 1–5°C cooler in spring and summer. The reservoir also reaches its maximum temperature 3–5 weeks later. The impoundment induced a net radiative cooling of −21 W m−2 compared to forest, featuring a pronounced winter deficit (−60 to −140 W m−2) due to snow cover albedo effects, partially compensated by summer surpluses (+5 to +50 W m−2).
File:
Sector(s):
Forests
Catégorie(s):
Scientific Article
Theme(s):
Ecosystems and Environment, Forest Ecology, Forest Growth and Yield Modelling, Forestry Research, Forests
Departmental author(s):
Author(s):
BEN ABA, Imen, Daniel F. NADEAU, Jean-Daniel SYLVAIN, Guillaume DROLET and François ANCTIL
Year of publication:
2025
Format:
Keyword(s):
écologie forestière, forest ecology, modélisation de la croissance et du rendement des forêts, forest growth and yield modelling, écosystèmes et environnement, ecosystems and environment, article scientifique, scientific article, land management, Land use, boreal forest, albedo, radiation, balance, climate change, gestion du territoire, occupation du sol, Forêt boréale, Albédo, bilan radiatif, changement climatique