Details zur Publikation |
| Kategorie | Textpublikation |
| Referenztyp | Zeitschriften |
| DOI | 10.1016/j.jag.2024.103910 |
Lizenz  |
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| Titel (primär) | Quantitative assessment of various proxies for downscaling coarse-resolution VOD products over the contiguous United States |
| Autor | Zhong, S.; Fan, L.; De Lannoy, G.; Frappart, F.; Zeng, J.; Vreugdenhil, M.; Peng, J.
; Liu, X.; Xing, Z.; Wang, M.; Li, X.; Wang, H.; Wigneron, J.-P. |
| Quelle | International Journal of Applied Earth Observation and Geoinformation |
| Erscheinungsjahr | 2024 |
| Department | RS |
| Band/Volume | 130 |
| Seite von | art. 103910 |
| Sprache | englisch |
| Topic | T5 Future Landscapes |
| Supplements | https://ars.els-cdn.com/content/image/1-s2.0-S1569843224002644-mmc1.docx |
| Keywords | Active microwave; Passive microwave; Vegetation optical depth (VOD); Sentinel-1; Optical indices |
| Abstract | Vegetation Optical Depth (VOD), a vegetation parameter that quantifies the extinction effect of microwaves penetrating the canopy, plays a crucial role in global-scale biomass monitoring and climate change research. However, the spatial gridding of existing long-term VOD products is relatively coarse (approximately 25 km), with restrictions on their application at a regional scale. High-resolution active-microwave proxies and optical vegetation indices can potentially be used to disaggregate coarse-resolution VOD, but it is unclear which proxy is optimal. In this paper, the Normalized Difference Vegetation Index (NDVI) and active-microwave proxies (VH, VV, and cross-polarization ratio CR) from Sentinel-1 were quantitatively assessed with VOD products at various frequencies (L-/C-/X-VOD) across the contiguous United States (U.S.). The results showed that VH (R = 0.80) and NDVI (R = 0.77) exhibit a high spatial correlation with L-VOD products. For temporal correlation, NDVI had the highest overall performances with all VOD products, but good correlations were also achieved with CR and, to a lesser extent, VH. Further comparisons of the performance between Brightness Temperature (TB) and VOD revealed that while TB displayed a strong temporal correlation with active-microwave proxies, its spatial correlations with such proxies were low. In contrast, VOD had good correlations both temporally and spatially with active-microwave proxies (e.g., VH). These evidences suggested that the downscaling of VOD using the combination of VH and other proxies could be an alternative promising method to estimate high-resolution VOD. |
| dauerhafte UFZ-Verlinkung | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=29243 |
| Zhong, S., Fan, L., De Lannoy, G., Frappart, F., Zeng, J., Vreugdenhil, M., Peng, J., Liu, X., Xing, Z., Wang, M., Li, X., Wang, H., Wigneron, J.-P. (2024): Quantitative assessment of various proxies for downscaling coarse-resolution VOD products over the contiguous United States Int. J. Appl. Earth Obs. Geoinf. 130 , art. 103910 10.1016/j.jag.2024.103910 |
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