Three years of soil moisture observations by a dense cosmic-ray neutron sensing cluster at an agricultural research site in north-east Germany

Abstract

Abstract. Cosmic-ray neutron sensing (CRNS) allows for the estimation of root-zone soil water content (SWC) at the scale of several hectares. In this paper, we present the data recorded by a dense CRNS network operated from 2019 to 2022 at an agricultural research site in Marquardt, Germany – the first multi-year CRNS cluster. Consisting, at its core, of eight permanently installed CRNS sensors, the cluster was supplemented by a wealth of complementary measurements: data from seven additional temporary CRNS sensors, partly collocated with the permanent ones, 27 SWC-profiles (mostly permanent), two groundwater observation wells, meteorological records, and global navigation satellite system reflectometry (GNSS-R). Complementary to these continuous measurements, numerous campaign-based activities provided data by mobile CRNS-roving, hyperspectral imagery via unmanned aerial systems (UAS), intensive manual sampling of soil properties (SWC, bulk density, organic matter, texture, soil hydraulic properties), and observations of biomass and snow (cover, depth, and density). The unique temporal coverage of three years entails a broad spectrum of hydro-meteorological conditions, including exceptional drought periods, extreme rainfall, but also episodes of snow coverage, as well as a dedicated irrigation experiment. Apart from serving to advance CRNS-related retrieval methods, this data set is expected to be useful for various disciplines, e.g. soil and groundwater hydrology, agriculture, or remote sensing. Hence, we show exemplary features of the data set in order to highlight the potential for such subsequent studies. The data is available at https://doi.org/10.23728/b2share.edfdaa0d2a82477fa512bde3f53312f2 (Heistermann et al., 2022b).

Technical Note: revisiting the general calibration of cosmic-rayneutron sensors to estimate soil water content

“…In order to obtain a scaling factor f s in , we scale ξ at any location (λ, ϕ, z) by ξ at an arbitrary location defined by λ 0 =12.97°, ϕ 0 =52.47°, and z 0 =40 m). This arbitrary location corresponds to the research site in Marquardt (about 10 km southwest of Berlin, Germany, see Heistermann et al, 2023).…”

“…Code and data availability. The four CRNS datasets used for this study were published via Copernicus' Earth System Science Data (Fersch et al, 2020;Heistermann et al, 2022;Bogena et al, 2022a;Heistermann et al, 2023). The PARMA model is openly available in the form of an Excel application (EXPACS), and as a C++ code, see https://phits.jaea.go.jp/expacs.…”