Erlangen 2018 – scientific programme

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UP: Fachverband Umweltphysik

UP 8: Methods - measurement techniques; Atmosphere - trace gases, mesosphere

UP 8.2: Talk

Wednesday, March 7, 2018, 14:15–14:30, G 1.011

Soil moisture measurement at the hectometer scale using CRNS for mobile applications — •Markus Köhli^1,2, Jannis Weimar¹, Martin Schrön³, and Ulrich Schmidt¹ — ¹Physikalisches Institut, Universität Heidelberg, Heidelberg, Germany — ²Im Neuenheimer Feld 226 — ³Helmholtz Zentrum für Umweltforschung, UFZ, Leipzig

The method of cosmic ray neutron sensing (CRNS) - soil moisture measurement at the hectometer scale non-invasively has turned out to be feasible by detecting environmental albedo neutron density. The key feature of the method is the exceptionally different behavior of hydrogen in its reflection power of neutrons generated by cosmic rays. It slows down fast neutrons whereas any other heavier element independent of the chemical composition rather reflects them. In the recent years the understanding of neutron transport by Monte-Carlo simulations led to major advancements in precision, which have been successfully targeted meanwhile by a manifold of experiments. Whereas the homogeneous conditions are well understood, inhomogeneous topologies are now in the focus of research. In our case these are applications for partial snow cover and mobile surveys, where the influence of the road material, which biased results towards lower soil moisture values, could be calculated, measured and analytically understood. Here we present the actual status of the method especially with respect to inhomogeneous terrain.