Vegetation angular signatures of equatorial forests from DSCOVR EPIC and Terra MISR observations
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Published version
Date
2021
Authors
Ni, Xiangnan
Knyazikhin, Yuri
Sun, Yuanheng
She, Xiaojun
Guo, Wei
Panferov, Oleg
Myneni, Ranga B.
Version
Published version
OA Version
Citation
X. Ni, Y. Knyazikhin, Y. Sun, X. She, W. Guo, O. Panferov, R.B. Myneni. "Vegetation Angular Signatures of Equatorial Forests From DSCOVR EPIC and Terra MISR Observations." Frontiers in Remote Sensing, Volume 2, https://doi.org/10.3389/frsen.2021.766805
Abstract
In vegetation canopies cross-shading between finite dimensional leaves leads to a peak in reflectance in the retro-illumination direction. This effect is called the hot spot in optical remote sensing. The hotspot region in reflectance of vegetated surfaces represents the most information-rich directions in the angular distribution of canopy reflected radiation. This paper presents a new approach for generating hot spot signatures of equatorial forests from synergistic analyses of multiangle observations from the Multiangle Imaging SpectroRadiometer (MISR) on Terra platform and near backscattering reflectance data from the Earth Polychromatic Imaging Camera (EPIC) onboard NOAA’s Deep Space Climate Observatory (DSCOVR). A canopy radiation model parameterized in terms of canopy spectral invariants underlies the theoretical basis for joining Terra MISR and DSCOVR EPIC data. The proposed model can accurately reproduce both MISR angular signatures acquired at 10:30 local solar time and diurnal courses of EPIC reflectance (NRMSE < 9%, R^2 > 0.8). Analyses of time series of the hot spot signature suggest its ability to unambiguously detect seasonal changes of equatorial forests.
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Copyright © 2021 Ni, Knyazikhin, Sun, She, Guo, Panferov and Myneni. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.