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| Hauptseite > Publikationsdatenbank > Use of satellite-based vegetation indices and thermal neutron intensities to investigate biomass effects on roving CRNS measurements |
| Hauptseite > Publikationsdatenbank > Use of satellite-based vegetation indices and thermal neutron intensities to investigate biomass effects on roving CRNS measurements |
| Conference Presentation (Other) | FZJ-2024-06963 |
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2024
Abstract: The use of roving cosmic-ray neutron sensors (CRNS) can provide soil moisture (SM) information over large areas. These can be extremely useful, for example, in the validation of land-surface models and satellite-based SM products. However, there are challenges in roving CRNS applications that are not yet resolved. For instance, detailed biomass information is often needed to obtain accurate SM estimates.Between June and November 2023, five roving CRNS measurements were performed in the Selke River catchment (Saxony Anhalt, Germany) as part of a joint field campaign of the CosmicSense project. Over 1000 km of measurements were conducted with the FZJ rover (Hydroinnova LLC, Albuquerque, NM, USA) that was equipped with 36 detector tubes. Of these tubes, 20 were moderated by 25 mm high density polyethylene (HDPE) to measure neutrons in the epithermal energy regime while 16 tubes were left bare to shift the measured energy towards the thermal energy regime.In addition, 19 stationary CRNS along different land covers of the study area were available for support. Four of these were CRS-2000 (Hydroinnova LLC, Albuquerque, NM, USA) equipped with moderated and bare detectors that were placed in agricultural areas. Vegetation indices such as NDVI were derived from Sentinel-2 satellite images at 10 m resolution to estimate/proxy biomass close to the roving dates. Additionally, land cover and land use information were used to stratify the study area into the most representative cover types.The temporal and spatial relationships between satellite-based vegetation indices and thermal or epithermal neutron intensities were investigated. The SM estimated from epithermal neutrons was compared with data from the available stationary CRNS and from in-situ measurements and samples. It was then explored whether thermal neutron intensities can be used to improve roving SM estimates by providing on-the-fly corrections of epithermal measurements for the surrounding biomass.
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