Details zur Publikation

Kategorie Datenpublikation
DOI 10.5281/zenodo.15275610
Lizenz creative commons licence
Titel (primär) Simulated spectral irradiances, radiances, and vegetation albedo obtained from coupling libRadtran and SCOPE2.0 (1.0) [Data set]
Autor Wolf, K.; Jäkel, E.; Ehrlich, A.; Schäfer, M.; Feilhauer, H.; Huth, A.; Wendisch, M.
Quelle Zenodo
Erscheinungsjahr 2025
Department OESA
Sprache englisch
Topic T5 Future Landscapes
Abstract Field observations of vegetation indices (VIs) are derived from ratios of spectral reflectance data that are collected by drones and aircraft, providing higher spatial resolution than satellites. These reflectance data require periodic reference measurements over calibrated reflectance panels under cloud-free conditions. However, the reference measurements are partly performed in cloudy situations with the effect that wavelength-dependent scattering and absorption of solar radiation by clouds affects the subsequently derived VIs. This paper quantifies these effects using combined atmosphere-vegetation radiative transfer (RT) simulations. We study the general case when VIs are obtained from reflectance ratios of two wavelengths, and for the special cases of the normalized difference vegetation index (NDVI), the normalized difference water index (NDWI), and the enhanced vegetation index (EVI). For the general case of two-band VIs the lowest sensitivity to cloud changes was found for wavelength combinations below 1400 nm and outside the water vapor absorption bands. The NDVI was almost insensitive to changes in cloud conditions, while greater biases were identified for the NDWI. The EVI was most susceptible to cloud changes, with biases of 0.2 in the selected example. This lead to biases in the estimated leaf area index of 0.9. Biophysical properties derived from EVI, such as gross primary product, are also affected with variations of up to +/- 2 gCm-2d-1 in the selected cases.
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Wolf, K., Jäkel, E., Ehrlich, A., Schäfer, M., Feilhauer, H., Huth, A., Wendisch, M. (2025):
Simulated spectral irradiances, radiances, and vegetation albedo obtained from coupling libRadtran and SCOPE2.0 (1.0) [Data set]
Zenodo 10.5281/zenodo.15275610