Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.5194/gi-7-83-2018 |
Licence  |
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| Title (Primary) | Intercomparison of cosmic-ray neutron sensors and water balance monitoring in an urban environment |
| Author | Schrön, M.; Zacharias, S.
; Womack, G.; Köhli, M.; Desilets, D.; Oswald, S.E.; Bumberger, J.
; Mollenhauer, H.; Kögler, S.; Remmler, P.
; Kasner, M.; Denk, A.; Dietrich, P.
|
| Source Titel | Geoscientific Instrumentation, Methods and Data Systems |
| Year | 2018 |
| Department | MET |
| Volume | 7 |
| Issue | 1 |
| Page From | 83 |
| Page To | 99 |
| Language | englisch |
| Supplements | https://www.geosci-instrum-method-data-syst.net/7/83/2018/gi-7-83-2018-supplement.zip |
| UFZ wide themes | TERENO; RU5; |
| Abstract | Sensor-to-sensor variability is a source of
error common to all geoscientific instruments that needs to be assessed
before comparative and applied research can be performed with multiple
sensors. Consistency among sensor systems is especially critical when
subtle features of the surrounding terrain are to be identified.
Cosmic-ray neutron sensors (CRNSs) are a recent technology used to
monitor hectometre-scale environmental water storages, for which a
rigorous comparison study of numerous co-located sensors has not yet
been performed. In this work, nine stationary CRNS probes of type CRS1000were installed in relative proximity on a grass patch surrounded by trees, buildings, and sealed areas. While the dynamics of the neutron count rates were found to be similar, offsets of a few percent from the absolute average neutron count rates were found. Technical adjustments of the individual detection parameters brought all instruments into good agreement. Furthermore, we found a critical integration time of 6 h above which all sensors showed consistent dynamics in the data and their RMSE fell below 1 % of gravimetric water content. The residual differences between the nine signals indicated local effects of the complex urban terrain on the scale of several metres. Mobile CRNS measurements and spatial simulations with the URANOS neutron transport code in the surrounding area (25 ha) have revealed substantial sub-footprint heterogeneity to which CRNS detectors are sensitive despite their large averaging volume. The sealed and constantly dry structures in the footprint furthermore damped the dynamics of the CRNS-derived soil moisture. We developed strategies to correct for the sealed-area effect based on theoretical insights about the spatial sensitivity of the sensor. This procedure not only led to reliable soil moisture estimation during dry-out periods, it further revealed a strong signal of intercepted water that emerged over the sealed surfaces during rain events. The presented arrangement offered a unique opportunity to demonstrate the CRNS performance in complex terrain, and the results indicated great potential for further applications in urban climate research. |
| Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=20011 |
| Schrön, M., Zacharias, S., Womack, G., Köhli, M., Desilets, D., Oswald, S.E., Bumberger, J., Mollenhauer, H., Kögler, S., Remmler, P., Kasner, M., Denk, A., Dietrich, P. (2018): Intercomparison of cosmic-ray neutron sensors and water balance monitoring in an urban environment Geosci. Instrum. Method. Data Syst. 7 (1), 83 - 99 10.5194/gi-7-83-2018 |
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