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https://doi.org/10.5194/egusphere-2022-219
https://doi.org/10.5194/egusphere-2022-219
25 Apr 2022
 | 25 Apr 2022

Signal contribution of distant areas to cosmic-ray neutron sensors – implications on footprint and sensitivity

Martin Schrön, Markus Köhli, and Steffen Zacharias

Abstract. This paper presents a new theoretical concept to estimate the contribution of distant areas to the measurement signal of cosmic-ray neutron detectors for snow and soil moisture monitoring. The algorithm is based on the local neutron production and their transport mechanism, given by the neutron-moisture relationship and the radial intensity function, respectively. The purely analytical approach has been validated with physics-based neutron transport simulations for heterogeneous soil moisture patterns, exemplary landscape features, and remote fields at a distance. We found that the method provides good approximations of simulated signal contributions in patchy soils with typical deviations of less than 1 %. Moreover, implications of this concept have been investigated for the neutron-moisture relationship, where the signal contribution of an area has the potential to explain deviating shapes of this curve that are often reported in literature. Finally, the concept has been used to develop a new practical footprint definition to express whether or not a distant area's soil moisture change is actually detectable in terms of measurement precision. The presented concepts answer long lasting questions about the influence of distant landscape structures in the integral footprint of the sensor without the need for computationally expensive simulations. The new insights are highly relevant to support signal interpretation, data harmonization, and sensor calibration, and will be particularly useful for sensors positioned in complex terrain or on agriculturally managed sites.

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Journal article(s) based on this preprint

09 Feb 2023
Signal contribution of distant areas to cosmic-ray neutron sensors – implications for footprint and sensitivity
Martin Schrön, Markus Köhli, and Steffen Zacharias
Hydrol. Earth Syst. Sci., 27, 723–738, https://doi.org/10.5194/hess-27-723-2023,https://doi.org/10.5194/hess-27-723-2023, 2023
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

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This paper presents a new analytical concept to answer long lasting questions of the cosmic-ray...
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