A new approach combining a multilayer radiative transfer model with an individual based forest model: Application to boreal forests in Finland

• Published in: Remote Sensing
• Main Authors: Henniger, Hans, Bohn, Friedrich, Schmidt, Kim, Huth, Andreas
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI, Basel 2023
• Subjects: forest model; radiative transfer; vegetation indices; individual based; forest reflectance; karelia*
• Online Access: https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=27112; https://doi.org/10.3390/rs15123078

To understand forest dynamics under today’s changing environmental conditions, it is important to analyze the state of forests at large scales. Forest inventories are not available for all regions, so it is important to use other additional sources of information, e.g. remote sensing observations. Increasingly, remotely sensed data based on optical instruments and airborne LIDAR are becoming widely available for forests. There is great potential in analyzing these measurements and gaining an understanding of forests state. In this work, we combine the new generation radiative transfer model mScope with the individual-based forest model FORMIND to generate reflectance spectra for forests. Combining the two models allows us to account for species diversity at different height layers in the forest. We compare the generated reflectances for forest stands in Finland, in the region of North Karelia, with Sentinel-2 measurements. We investigate which level of forest representation gives the best results. For the majority of the forest stands, we generated good reflectances with all levels forest representation compared to the measured reflectance. Good correlations were also found for the vegetation indices (especially NDVI with R²=0.62). This work provides a forward modelling tool for relating forest reflectance to forest characteristics. With this tool it is possible to generate a large set of forest stands with corresponding reflectances. This opens the possibility to understand how reflectance is related to succession and different forest conditions.