Measuring soil moisture content non‐invasively at intermediate spatial scale using cosmic‐ray neutrons

Zréda, Marek; Desilets, Darin; Ferré, T. P. A.; Scott, Russell L.

doi:10.1029/2008gl035655

Cited by 456 publications

(672 citation statements)

References 32 publications

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“…The vertical component of the error ellipse represents the standard error of the mean for depth-averaged samples taken in manual soil surveys. The horizontal component represents the standard error in the moisture determination propagated from the statistical uncertainty in the counting rate [Zreda et al, 2008]. Error bars give the standard deviation of the depth-averaged samples, while the vertical rectangles encompass the entire range of depth-averaged samples.…”

Section: A2 Roving Measurements In Hawaiimentioning

confidence: 99%

“…The effect of soil moisture on cosmic ray neutron intensity above the ground surface was identified in measurements made over four decades ago [Hendrick and Edge, 1966] but was considered noise in the measurement of neutrons. More recently, applications to hydrology have been recognized [Zreda et al, 2008].…”

Section: Introductionmentioning

confidence: 99%

“…[5] In a previous paper [Zreda et al, 2008] we described the application of the cosmic ray technique to the field-scale determination of soil moisture content at a grassland site in southeastern Arizona, USA. Fixed monitoring stations similar to that one are now being implemented in COSMOS (Cosmic Ray Soil Moisture Observing System; cosmos.hwr.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Nature's neutron probe: Land surface hydrology at an elusive scale with cosmic rays

Desilets

Zréda

Ferré

2010

Water Resources Research

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[1] Fast neutrons are generated naturally at the land surface by energetic cosmic rays. These "background" neutrons respond strongly to the presence of water at or near the land surface and represent a hitherto elusive intermediate spatial scale of observation that is ideal for land surface studies and modeling. Soil moisture, snow, and biomass each have a distinct influence on the spectrum, height profile, and directional intensity of neutron fluxes above the ground, suggesting that different sources of water at the land surface can be distinguished with neutron data alone. Measurements can be taken at fixed sites for long-term monitoring or in a moving vehicle for mapping over large areas. We anticipate applications in many previously problematic contexts, including saline environments, wetlands and peat bogs, rocky soils, the active layer of permafrost, and water and snow intercepted by vegetation, as well as calibration and validation of data from spaceborne sensors.Citation: Desilets, D., M. Zreda, and T. P. A. Ferré (2010), Nature's neutron probe: Land surface hydrology at an elusive scale with cosmic rays, Water Resour. Res., 46, W11505,

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Section: A2 Roving Measurements In Hawaiimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Nature's neutron probe: Land surface hydrology at an elusive scale with cosmic rays

Desilets

Zréda

Ferré

2010

Water Resources Research

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308

462

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“…The radius of the horizontal footprint of the CRNS, the region containing 86% of the detected neutrons, is estimated to be about 300 m by Desilets and Zreda (2013) and from 130 to 240 m by Köhli et al (2015) at sea level (atmospheric pressure of 1013 hPa). The surveying depth is estimated to be about 12 cm (saturated soil) to 76 cm (dry soil) by Zreda et al (2008) and from 15 to 83 cm by Köhli et al (2015). A hectometer scale can compensate the deficiency of soil moisture observation between point and remote sensing images.…”

Section: Introductionmentioning

confidence: 99%

Application of cosmic-ray neutron sensing to monitor soil water content in an alpine meadow ecosystem on the northern Tibetan Plateau

Zhu

Shao

Zeng

et al. 2016

Journal of Hydrology

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Keywords: CRNS Soil moisture Alpine meadow Tibetan Plateau s u m m a r y Cosmic-ray neutron sensing (CRNS) is a new method for continuously monitoring mean soil water content (SWC) on a hectometer scale. To evaluate the application and accuracy of the method for SWC observation in an alpine meadow ecosystem (AME), we installed the CRNS in a flat meadow near the Naqu prefecture on the northern Tibetan Plateau. We collecting soil samples and applying the system by the oven-drying method. A weather station was also installed near the CRNS for monitoring basic meteorological variables and the soil temperature and water content at various depths. Three Em-50 instruments for monitoring SWC and soil temperature were buried in three sub-quadrats northwest, northeast and southeast of the CRNS at distances of 460, 370 and 373 m, respectively, to observe the variation of SWC at the various depths. The footprint of the CRNS for SWC observation in the meadow was about 580 m, and the mean measuring depth was about 31 cm according to the general calculation equations. The reference neutron flux for dry soil (N 0 ) had a mean and coefficient of variation of 8686 and 3%, respectively, and remained substantially invariant throughout the measuring period. The five SWCs from the independent field samples almost passed through the SWC trend of the CRNS, the root mean square error (RMSE) was 0.011 m 3 m À3 for the CRNS and oven-drying method. The time series of SWC measured by the CRNS agreed well with the mean SWC series to a depth of 20 cm measured by the weather station. The trend of SWC measured by the Em-50s generally agreed with the trend of SWC measured by the CRNS, but some values and variations of SWC differed between the Em-50s and CRNS data. Because of the good agreement between the CRNS and independent field samples, we suspect that this disagreement is due to an insufficient representativeness of point observations and the distances of the points from the CRNS. The diurnal variation of hourly SWC from the CRNS was sinusoidal during a dry period, peaking at 11:00 and was minimum at 18:00 (Beijing time), with a range of 1%. Overall, the CRNS measured SWC in the AME with an acceptable accuracy, providing a scientific basis for the promotion and application of the CRNS in high, cold ecosystems.

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“…Other applications of neutron detectors use above ground measurements of natural slow neutrons emitted upwards from the soil water under influence of cosmic rays. These measurements have a footprint of 10-100 m and are sensitive to moisture at a depth of 10-100 cm [50,51].…”

Section: Neutron Probesmentioning

confidence: 99%

Soil Moisture & Snow Properties Determination with GNSS in Alpine Environments: Challenges, Status, and Perspectives

et al. 2013

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Moisture content in the soil and snow in the alpine environment is an important factor, not only for environmentally oriented research, but also for decision making in agriculture and hazard management. Current observation techniques quantifying soil moisture or characterizing a snow pack often require dedicated instrumentation that measures either at point scale or at very large (satellite pixel) scale. Given the heterogeneity of both snow cover and soil moisture in alpine terrain, observations of the spatial distribution of moisture and snow-cover are lacking at spatial scales relevant for alpine hydrometeorology. This paper provides an overview of the challenges and status of the determination of soil moisture and snow properties in alpine environments. Current measurement techniques and newly proposed ones, based on the reception of reflected Global Navigation Satellite Signals (i.e., GNSS Reflectometry or GNSS-R), or the use of laser scanning are reviewed, and the perspectives offered by these new techniques to fill the current gap in the instrumentation level are discussed. Some key enabling technologies OPEN ACCESSRemote Sens. 2013, 5 3517 including the availability of modernized GNSS signals and GNSS array beamforming techniques are also considered and discussed.

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Measuring soil moisture content non‐invasively at intermediate spatial scale using cosmic‐ray neutrons

Cited by 456 publications

References 32 publications

Nature's neutron probe: Land surface hydrology at an elusive scale with cosmic rays

Nature's neutron probe: Land surface hydrology at an elusive scale with cosmic rays

Application of cosmic-ray neutron sensing to monitor soil water content in an alpine meadow ecosystem on the northern Tibetan Plateau

Soil Moisture & Snow Properties Determination with GNSS in Alpine Environments: Challenges, Status, and Perspectives

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