Tuesday, 14 January 2025
Hall C (New Orleans Ernest N. Morial Convention Center)
The importance of measuring hydrological variables like Soil Water Content (SWC) or Snow Water Equivalent (SWE) is widely recognised for a vast range of applications. Hydrological balance is crucial for the rational use of water resources in agriculture, power generation and industry; knowledge of such variables is also crucial to improve early warning systems for environmental hazards like floods, droughts, landslides, avalanches and wildfires. Long-time monitoring of hydrological variables amid climate change is also an aim by itself.
However, hydrological variables are notably more difficult to measure than meteorological variables. Common technologies to measure SWC are invasive point-scale probes, which are hardly representative of a wider area, unsuitable for coarse-textured soils and easy to be broken or lost. Nivological stations commonly rely on nivometers to measure snow depth, that is not straighforwardly related to SWE and moreover comes as a punctual information, that may miss the inhomogeneous distribution of the snowpack. In both cases, the main alternative is remote sensing, which suffers limits related to spatial resolution, measurement depth and continuity.
As an attempt to compensate for the lack of measurements of hydrological variables, computational models are widely used to derive them from meteorological ones. For example, the Canadian-developed Fire Weather Index relies mainly on precipitations and temperature to evaluate the dryness of the soil; the Swiss-developed SNOWPACK model uses wind, temperature and solar radiation data, together with the snow depth provided by nivometers, to model the layering of the snowpack and derive the total SWE. Indeed models still need measured data to be validated and improved.
Nowadays proximal sensors based on the concept of Cosmic Rays Neutrons Sensing (CRNS) are a viable option for the measurement of both SWC and SWE. CRNS is based on the detection of neutrons, which are generated in the atmosphere by the interaction of cosmic rays (high energy particles naturally flowing from space), then backscattered by the soil and effectively absorbed by water in any form, due to their strong interaction with hydrogen. After proper calibration, CRNS allows to infer SWC or SWE from neutron counts. Thanks to the propagation distance of neutrons through air, soil or snow, the provided measurement is averaged over a large footprint and in depth, thus filling the scale gap between point-scale and remote sensing and providing a reasonably sized ground reference to calibrate satellites observations.
In recent decades, some CRNS networks were deployed, notably COSMOS-US and COSMOS-UK for the national-scale monitoring of SWC and the French network created by Électricité de France for the measurement of SWE for hydropower purposes. The traditional technology for CRNS is based on tubes filled with 3He as the sensitive material. As the need was felt of neutrons detectors reliant on safer and more easily available materials, Finapp developed a suitable detector based on a lithium-doped solid scintillator material. The resulting device is lighter, more handy and cheaper than 3He tubes and opens the way to new widespread applicability. Thanks to the low power consumption, the system can function off-grid and be an autonomous station even in remote areas, while transmitting data at pre-set temporal intervals through GSM or data-logger.
The Finapp detector also has the unique additional property of being able to monitor the fluctuations of the incoming cosmic rays flux, by observing the flux of muons as a reference. This remove the needs of an external reference, thus making the system autonomous in processing the signal on-board and providing the final value of either SWC or SWE.
In this presentation we will report some examples of applications of Finapp CRNS systems in Northern Italy, related to both the measurements of SWE and SWC, highlighting how a single probe can find multiple scopes.
This work involves the use of data provided by courtesy of ARPAV (Dipartimento Regionale per la Sicurezza del Territorio), ARPA Piemonte and ARPAE Emilia-Romagna. Part of the activities is related to the MOSAIC Project (Managing prOtective foreSt fAcIng clImate Change compound events), co-funded by the European Union through the Interreg Alpine Space programme (Project ID: ASP0100014).
However, hydrological variables are notably more difficult to measure than meteorological variables. Common technologies to measure SWC are invasive point-scale probes, which are hardly representative of a wider area, unsuitable for coarse-textured soils and easy to be broken or lost. Nivological stations commonly rely on nivometers to measure snow depth, that is not straighforwardly related to SWE and moreover comes as a punctual information, that may miss the inhomogeneous distribution of the snowpack. In both cases, the main alternative is remote sensing, which suffers limits related to spatial resolution, measurement depth and continuity.
As an attempt to compensate for the lack of measurements of hydrological variables, computational models are widely used to derive them from meteorological ones. For example, the Canadian-developed Fire Weather Index relies mainly on precipitations and temperature to evaluate the dryness of the soil; the Swiss-developed SNOWPACK model uses wind, temperature and solar radiation data, together with the snow depth provided by nivometers, to model the layering of the snowpack and derive the total SWE. Indeed models still need measured data to be validated and improved.
Nowadays proximal sensors based on the concept of Cosmic Rays Neutrons Sensing (CRNS) are a viable option for the measurement of both SWC and SWE. CRNS is based on the detection of neutrons, which are generated in the atmosphere by the interaction of cosmic rays (high energy particles naturally flowing from space), then backscattered by the soil and effectively absorbed by water in any form, due to their strong interaction with hydrogen. After proper calibration, CRNS allows to infer SWC or SWE from neutron counts. Thanks to the propagation distance of neutrons through air, soil or snow, the provided measurement is averaged over a large footprint and in depth, thus filling the scale gap between point-scale and remote sensing and providing a reasonably sized ground reference to calibrate satellites observations.
In recent decades, some CRNS networks were deployed, notably COSMOS-US and COSMOS-UK for the national-scale monitoring of SWC and the French network created by Électricité de France for the measurement of SWE for hydropower purposes. The traditional technology for CRNS is based on tubes filled with 3He as the sensitive material. As the need was felt of neutrons detectors reliant on safer and more easily available materials, Finapp developed a suitable detector based on a lithium-doped solid scintillator material. The resulting device is lighter, more handy and cheaper than 3He tubes and opens the way to new widespread applicability. Thanks to the low power consumption, the system can function off-grid and be an autonomous station even in remote areas, while transmitting data at pre-set temporal intervals through GSM or data-logger.
The Finapp detector also has the unique additional property of being able to monitor the fluctuations of the incoming cosmic rays flux, by observing the flux of muons as a reference. This remove the needs of an external reference, thus making the system autonomous in processing the signal on-board and providing the final value of either SWC or SWE.
In this presentation we will report some examples of applications of Finapp CRNS systems in Northern Italy, related to both the measurements of SWE and SWC, highlighting how a single probe can find multiple scopes.
This work involves the use of data provided by courtesy of ARPAV (Dipartimento Regionale per la Sicurezza del Territorio), ARPA Piemonte and ARPAE Emilia-Romagna. Part of the activities is related to the MOSAIC Project (Managing prOtective foreSt fAcIng clImate Change compound events), co-funded by the European Union through the Interreg Alpine Space programme (Project ID: ASP0100014).
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