Projekteja vuodessa
Abstrakti
We report a new version and an empirical evaluation of a forest reflectance model based on photon recollision probability (p). For the first time, a p-based approach to modeling forest reflectance was tested in a wide range of differently structured forests from different biomes. To parameterize the model, we measured forest canopy structure and spectral characteristics for 50 forest plots in four study sites spanning from boreal to temperate biomes in Europe (48°–62°N). We compared modeled forest reflectance spectra against airborne hyperspectral data at wavelengths of 450–2200 nm. Large overestimation occurred, especially in the near-infrared region, when the model was parameterized considering only leaves or needles as plant elements and assuming a Lambertian canopy. The model root mean square error (RMSE) was on average 80%, 80%, 54% for coniferous, broadleaved, and mixed forests, respectively. We suggest a new parameterization that takes into account the nadir to hemispherical reflectance ratio of the canopy and contribution of woody elements to the forest reflectance. We evaluated the new parameterization based on inversion of the model, which resulted in average RMSE of 20%, 15%, and 11% for coniferous, broadleaved, and mixed forests. The model requires only few structural parameters and the spectra of foliage, woody elements, and forest floor as input. It can be used in interpretation of multi- and hyperspectral remote sensing data, as well as in land surface and climate modeling. In general, our results also indicate that even though the foliage spectra are not dramatically different between coniferous and broadleaved forests, they can still explain a large part of reflectance differences between these forest types in the near-infrared, where sensitivity of the reflectance of dense forests to changes in the scattering properties of the foliage is high.
Alkuperäiskieli | Englanti |
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Artikkeli | 112804 |
Sivumäärä | 20 |
Julkaisu | Remote Sensing of Environment |
Vuosikerta | 269 |
DOI - pysyväislinkit | |
Tila | Julkaistu - helmik. 2022 |
OKM-julkaisutyyppi | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä |
Sormenjälki
Sukella tutkimusaiheisiin 'Assessment of a photon recollision probability based forest reflectance model in European boreal and temperate forests'. Ne muodostavat yhdessä ainutlaatuisen sormenjäljen.Projektit
- 3 Päättynyt
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DIMEBO: Boreaalisten metsien spektrinen diversiteetti
Rautiainen, M. (Vastuullinen tutkija), Kuusinen, N. (Projektin jäsen), Juola, J. (Projektin jäsen) & Salko, S.-S. (Projektin jäsen)
01/09/2019 → 30/06/2022
Projekti: Academy of Finland: Other research funding
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FREEDLES: From needles to landscapes: a novel approach to scaling forest spectra
Rautiainen, M. (Vastuullinen tutkija), Hovi, A. (Projektin jäsen), Juola, J. (Projektin jäsen), Mercier, A. (Projektin jäsen), Salko, S.-S. (Projektin jäsen), Rönkkö, J. (Projektin jäsen), Karlqvist, S. (Projektin jäsen) & Schraik, D. (Projektin jäsen)
01/05/2018 → 30/04/2024
Projekti: EU: ERC grants
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BOREALITY: Boreaalisen metsän vuodenaikaisvaihteluiden mittaaminen avaruudesta: mikä on metsän albedon, tuotoksen ja fenologian yhteys?
Hovi, A. (Projektin jäsen), Rautiainen, M. (Vastuullinen tutkija), Majasalmi, T. (Projektin jäsen), Juola, J. (Projektin jäsen) & Palviainen, P. (Projektin jäsen)
01/09/2015 → 31/12/2019
Projekti: Academy of Finland: Other research funding
Laitteet
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i3 – Industry Innovation Infrastructure
Sainio, P. (Manager)
Insinööritieteiden korkeakouluLaitteistot/tilat: Facility
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