Neutrons on Rails - trans-regional monitoring of soil moisture and snow
water equivalent
Abstract
Large-scale measurements of the spatial distribution of water content in
soils and snow are challenging for state-of-the-art hydrogeophysical
methods. Cosmic-ray neutron sensing (CRNS) is a non-invasive technology
that has the potential to bridge the scale gap between conventional
in-situ sensors and remote-sensing products in both, horizontal and
vertical domains. In this study we explore the feasibility and potential
of estimating water content in soils and snow with neutron detectors in
moving trains. Theoretical considerations quantify the stochastic
measurement uncertainty as a function of water content, altitude,
resolution, and detector efficiency. Numerical experiments demonstrate
that the sensitivity of measured water content is almost unperturbed by
train materials. And finally three distinct real world experiments
provide a proof of concept on short and long-range tracks. With our
results a trans-regional observational soil moisture product becomes a
realistic vision within the next years.