EGU24-16814, updated on 09 Apr 2024
https://doi.org/10.5194/egusphere-egu24-16814
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Revisiting the barometric effect on cosmic-ray neutron soil moisture sensing

Patrick Davies1, Roland Baatz2, Heye Bogena3, Emmanuel Quansah1, and Leonard Amekudzi1
Patrick Davies et al.
  • 1Kwame Nkrumah University of Science and Technology (KNUST), Meteorology and Climate Science, Ghana
  • 2Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalder Str. 84, 15374 Muncheberg, Germany
  • 3Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, Germany.

Accurate soil moisture estimation from Cosmic-ray neutron sensor (CRNS) entails necessary steps in pre-processing observed neutrons at the Earth's surface. One of the most important corrections to the measured neutron data is compensation for the influence of the atmosphere, also called the barometric effect (β). However, the correction for this effect is not universal, as values can vary depending on geographical location (i.e. cut-off rigidity), altitude, atmospheric conditions, and sensor type (i.e. energy range); hence, site-specific β values are required to reduce these offsets. In this study, 25 CRNS stations from around the world are used to estimate site-specific and to explore the sensitivity of β on soil moisture measurement with CRNS. The results obtained showed that β varied both spatially and temporally. Within the cut-off rigidity range of 1 to 4.5 GV where these sites are found, the average monthly for the investigated sites ranged between -0.53 to -0.96 %mbar. Although the cut-off rigidity range was small, we found an increasing relationship of β with increasing cut-off rigidity. In addition, we show how β affects soil moisture estimates through its effect on the atmospheric pressure correction during the CRNS calibration. The results of our study highlight the importance of site and sensor-specific for CRNS calibration and the correction of atmospheric effects on CRNS-derived soil moisture.

How to cite: Davies, P., Baatz, R., Bogena, H., Quansah, E., and Amekudzi, L.: Revisiting the barometric effect on cosmic-ray neutron soil moisture sensing, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16814, https://doi.org/10.5194/egusphere-egu24-16814, 2024.