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Research article - Peer-reviewed, 2019

Seasonal dynamics of albedo across European boreal forests: Analysis of MODIS albedo and structural metrics from airborne LiDAR

Hovi, Aarne; Lindberg, Eva; Lang, Mait; Arumae, Tauri; Peuhkurinen, Jussi; Sirparanta, Sanna; Pyankov, Sergey; Rautiainen, Miina

Abstract

Uncertainties in estimation of albedo-related radiative forcing cause ambiguity in evaluation of net climate effects of forests and forest management. Numerous studies have reported local relations between forest structure and albedo in the boreal zone. However, more research is needed to establish these relations for geographically extensive areas, and to examine seasonal courses of albedo to understand the effects of forest structure on mean annual shortwave energy balance. Remote sensing is a viable option for accomplishing these goals, but there are many challenges related to e.g. long periods of cloud cover and low solar elevations in high latitudes. We used the new MODIS Collection 6 (MCD43A3) daily albedo product, and analyzed MODIS albedo dependence on airborne LiDAR-based forest structure in 22 study sites in Estonia, Finland, Sweden, and Russia (57 degrees-69 degrees N, 12 degrees-57 degrees E). Wall-to-wall LiDAR data allowed us to take into account the effective spatial resolution of MODIS, which notably improved correlations between albedo and forest structure. Use of the best quality backup algorithm (magnitude inversion) together with main algorithm results in the MODIS albedo product did not reduce the correlations compared to using main algorithm only. We quantified the effects of landscape-level forest structure (forest height, canopy cover, fraction of young forest) and fraction of broadleaved deciduous forest on mean annual albedo. We showed that because the forest structure-albedo relations are the strongest in snow-covered periods, and because the snow-covered period is longest in the north, the effect of forest structure on mean annual albedo increases towards the north. On the other hand, the effect of broadleaved fraction did not show such latitudinal trend. Our results indicate that even within a single climatic zone the optimal forest management solution to mitigate climate change depends on geographic location.

Keywords

MODIS; Albedo; Seasonality; Boreal forests; Forest management

Published in

Remote Sensing of Environment
2019, volume: 224, pages: 365-381
Publisher: ELSEVIER SCIENCE INC

Authors' information

Hovi, Aarne
Aalto University
Swedish University of Agricultural Sciences, Department of Forest Resource Management
Lang, Mait
Estonian University of Life Sciences
Arumae, Tauri
Estonian University of Life Sciences
Peuhkurinen, Jussi
Arbonaut Oy Ltd
Sirparanta, Sanna
Arbonaut Oy Ltd
Pyankov, Sergey
Perm State University
Rautiainen, Miina
Aalto University

Sustainable Development Goals

SDG13 Climate action

UKÄ Subject classification

Remote Sensing
Forest Science

Publication Identifiers

DOI: https://doi.org/10.1016/j.rse.2019.02.001

URI (permanent link to this page)

https://res.slu.se/id/publ/99512