Evaluating Cosmic Ray Neutron Sensor Estimates of Snow Water Equivalent in a Prairie Environment Using UAV Lidar

Abstract Monitoring snow cover in prairie environments is important for understanding water and energy fluxes, agricultural production, and flooding, but difficult due to shallow snowpack and considerable snow heterogeneity. Cosmic ray neutron sensors (CRNS) are sensitive to snow within a radius of...

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Main Authors: M. Woodley, H. Kim, E. Sproles, J. Eberly, S. Tuttle
Format: Article
Language:English
Published: Wiley 2024-06-01
Series:Water Resources Research
Subjects:
Online Access:https://doi.org/10.1029/2024WR037164
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author M. Woodley
H. Kim
E. Sproles
J. Eberly
S. Tuttle
author_facet M. Woodley
H. Kim
E. Sproles
J. Eberly
S. Tuttle
author_sort M. Woodley
collection DOAJ
description Abstract Monitoring snow cover in prairie environments is important for understanding water and energy fluxes, agricultural production, and flooding, but difficult due to shallow snowpack and considerable snow heterogeneity. Cosmic ray neutron sensors (CRNS) are sensitive to snow within a radius of 150–250 m, which allows for continuous estimation of snow water equivalent (SWE) over a large footprint and may better represent area‐averaged snow cover in prairies than conventional SWE instruments, such as snow pillows. A CRNS was installed at Montana State University's Central Agricultural Research Center (CARC; 47.06°, −109.95°) in Moccasin, MT in coordination with NASA's SnowEx 2021 field campaign. This work assesses the feasibility of a CRNS for SWE monitoring in prairies by comparing CRNS SWE estimates to spatially distributed SWE derived from uninhabited aerial vehicle lidar snow depths within the sensor's footprint and manual snow pit measurements. Lidar observations show snow cover was highly spatially variable, with the largest snow accumulation near barriers and the least in barren fields. Additionally, we evaluate our CRNS SWE estimates using Ultra Rapid Neutron Only Simulation (URANOS) Monte Carlo simulations. Comparisons of SWE estimates derived from lidar, CRNS, and URANOS for shallow snowpack at the site yielded root mean square values of about 2 mm (approximately 30% of the mean SWE). These results suggest that the CRNS is effective at integrating over significant spatial variability within its footprint at this site. However, the spatial distribution of snow exerts a strong influence on the CRNS signal and must be considered when interpreting CRNS observations.
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spelling doaj-art-047858c7ca3f4602a3e5ce7dfe8d2da52025-08-20T03:30:54ZengWileyWater Resources Research0043-13971944-79732024-06-01606n/an/a10.1029/2024WR037164Evaluating Cosmic Ray Neutron Sensor Estimates of Snow Water Equivalent in a Prairie Environment Using UAV LidarM. Woodley0H. Kim1E. Sproles2J. Eberly3S. Tuttle4Syracuse University Syracuse NY USASyracuse University Syracuse NY USADepartment of Sciences Montana State University Bozeman MT USACentral Agricultural Research Center Montana State University Bozeman MT USASyracuse University Syracuse NY USAAbstract Monitoring snow cover in prairie environments is important for understanding water and energy fluxes, agricultural production, and flooding, but difficult due to shallow snowpack and considerable snow heterogeneity. Cosmic ray neutron sensors (CRNS) are sensitive to snow within a radius of 150–250 m, which allows for continuous estimation of snow water equivalent (SWE) over a large footprint and may better represent area‐averaged snow cover in prairies than conventional SWE instruments, such as snow pillows. A CRNS was installed at Montana State University's Central Agricultural Research Center (CARC; 47.06°, −109.95°) in Moccasin, MT in coordination with NASA's SnowEx 2021 field campaign. This work assesses the feasibility of a CRNS for SWE monitoring in prairies by comparing CRNS SWE estimates to spatially distributed SWE derived from uninhabited aerial vehicle lidar snow depths within the sensor's footprint and manual snow pit measurements. Lidar observations show snow cover was highly spatially variable, with the largest snow accumulation near barriers and the least in barren fields. Additionally, we evaluate our CRNS SWE estimates using Ultra Rapid Neutron Only Simulation (URANOS) Monte Carlo simulations. Comparisons of SWE estimates derived from lidar, CRNS, and URANOS for shallow snowpack at the site yielded root mean square values of about 2 mm (approximately 30% of the mean SWE). These results suggest that the CRNS is effective at integrating over significant spatial variability within its footprint at this site. However, the spatial distribution of snow exerts a strong influence on the CRNS signal and must be considered when interpreting CRNS observations.https://doi.org/10.1029/2024WR037164snow water equivalentlidarprairiecosmic ray neutron sensorURANOSMontana
spellingShingle M. Woodley
H. Kim
E. Sproles
J. Eberly
S. Tuttle
Evaluating Cosmic Ray Neutron Sensor Estimates of Snow Water Equivalent in a Prairie Environment Using UAV Lidar
Water Resources Research
snow water equivalent
lidar
prairie
cosmic ray neutron sensor
URANOS
Montana
title Evaluating Cosmic Ray Neutron Sensor Estimates of Snow Water Equivalent in a Prairie Environment Using UAV Lidar
title_full Evaluating Cosmic Ray Neutron Sensor Estimates of Snow Water Equivalent in a Prairie Environment Using UAV Lidar
title_fullStr Evaluating Cosmic Ray Neutron Sensor Estimates of Snow Water Equivalent in a Prairie Environment Using UAV Lidar
title_full_unstemmed Evaluating Cosmic Ray Neutron Sensor Estimates of Snow Water Equivalent in a Prairie Environment Using UAV Lidar
title_short Evaluating Cosmic Ray Neutron Sensor Estimates of Snow Water Equivalent in a Prairie Environment Using UAV Lidar
title_sort evaluating cosmic ray neutron sensor estimates of snow water equivalent in a prairie environment using uav lidar
topic snow water equivalent
lidar
prairie
cosmic ray neutron sensor
URANOS
Montana
url https://doi.org/10.1029/2024WR037164
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