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@INPROCEEDINGS{Brogi:1049553,
      author       = {Brogi, Cosimo and Bogena, Heye Reemt and Huisman, Johan
                      Alexander and Jakobi, Jannis and Schmidt, Marius and
                      Montzka, Carsten and Bates, Jordan and Akter, Sonia},
      title        = {{S}imultaneous monitoring of soil water content and
                      vegetation with cosmic-ray neutron sensors: novel findings
                      and future opportunities},
      reportid     = {FZJ-2025-05357},
      year         = {2025},
      abstract     = {Accurate and continuous monitoring of soil water content
                      (SWC) and plant development provides significant benefits in
                      various contexts, including long-term environmental
                      observatories, the development and validation of
                      environmental models and remote sensing products, as well as
                      practical applications like digital and sustainable
                      agriculture. Cosmic-Ray Neutron Sensors (CRNS) are becoming
                      increasingly popular for continuous and non-invasive
                      monitoring of SWC, and recent advancements have demonstrated
                      their potential for vegetation monitoring. CRNS use a
                      moderated detector to measure epithermal neutron intensity
                      (En) and estimate SWC over a radius of approximately 200 m.
                      An additional bare detector measures lower-energy thermal
                      neutron intensity (Tn), which is more sensitive to
                      vegetation biomass than to SWC. However, the benefits of
                      simultaneous monitoring of SWC and vegetation properties
                      with CNRS for monitoring networks such as ICOS and ILTER
                      have not been investigated yet.In this study, a CRNS that is
                      part of the COSMOS-Europe network measured En and Tn over a
                      10-year period at the ICOS Class 1 ecosystem station in
                      Selhausen, Germany (integrated into the already-present
                      TERENO station in 2019). En and Tn were compared to a large
                      dataset of a) SWC obtained from multiple point-scale sensors
                      within 30 m of the CRNS, b) gross primary productivity (GPP)
                      obtained with the eddy covariance (EC) method, and c) manual
                      and drone-based measurements of plant height (PH), leaf area
                      index (LAI), and dry aboveground biomass (AGB).Discrepancies
                      between the CRNS and the point-scale SWC measurements were
                      observed (RMSE of 0.063 cm3/cm3). These were attributed to
                      the periodic reinstallation of the point-scale sensors that
                      sometimes led to abrupt changes in measured SWC, and to the
                      fact that the CRNS, like the EC station, measures over a
                      much larger area. Thanks to the co-location of the CRNS and
                      EC station, a comparison of Tn and GPP showed a clear
                      co-development during cropping periods and the lower
                      responsiveness of Tn during senescence and desiccation
                      indicated that factors such as plant structure and other
                      hydrogen pools (e.g., below-ground biomass) may affect Tn.
                      Crop-specific or annual models were used to estimate plant
                      traits from Tn. The accuracy of plant traits predicted by
                      the CRNS was relatively lower compared to manual and
                      destructive methods (RMSE of 0.13 m for PH, 1.01 m for LAI,
                      and 0.27 kg/m2 for dry AGB). However, the effortless nature
                      of the CRNS outweighs this reduction in accuracy, opening
                      the possibility of generating continuous time series of
                      plant traits with only a few manual measurements.This study
                      showcases the potential of CRNS for simultaneous field-scale
                      monitoring of SWC and vegetation, which is of great interest
                      for monitoring platforms and environmental modelling.
                      Moreover, the novel findings obtained by comparing Tn and
                      GPP showed that strengthened collaboration between
                      observatories and networks such as COSMOS, TERENO, and ICOS,
                      can provide information that is not only useful for
                      researchers but also for instruments manufacturers. In fact,
                      the possibility to extend the usage of CRNS beyond SWC and
                      toward monitoring of plant traits could increase the
                      interest towards thermal neutron detection and vegetation
                      monitoring.},
      month         = {Apr},
      date          = {2025-04-27},
      organization  = {EGU 2025, Vienna (Austria), 27 Apr
                       2025 - 2 May 2025},
      subtyp        = {Other},
      cin          = {IBG-3},
      cid          = {I:(DE-Juel1)IBG-3-20101118},
      pnm          = {2173 - Agro-biogeosystems: controls, feedbacks and impact
                      (POF4-217) / DFG project G:(GEPRIS)413955144 - Verbesserte
                      Quantifizierung von Bodenfeuchte und Biomasse durch
                      Kombination von bodengestützter Neutronen- und
                      LiDAR-Sensorik und Modellierung (413955144)},
      pid          = {G:(DE-HGF)POF4-2173 / G:(GEPRIS)413955144},
      typ          = {PUB:(DE-HGF)24},
      doi          = {10.5194/egusphere-egu25-12743},
      url          = {https://juser.fz-juelich.de/record/1049553},
}