PROGRAM

 

Monday, Sept 23

18:00
Icebreaker sponsored by Quaesta Instruments LLC

Whiskey Bar of The Plough Inn, Hillsborough, BT266AG

Tuesday, Sept 24

09:00 Welcome by Steven Morrison, Head of AFBI Hillsborough

Session 1

Chair: Paul Schattan

09:10 Keynote: The physics of Cosmic-Ray Neutron Sensing: Neutron evaporation and propagation at the land atmosphere interface (Jannis Weimar)

09:40 Response of bare and moderated neutron detectors under different environmental conditions (Daniel Rasche, Martin Schrön, Jannis Weimar, Markus Köhli, Theresa Blume and Andreas Güntner)

10:00 Pushing the limits of COSMOS: monitoring water content in deserts, complex terrain, and airships (Martin Schrön, Nurit Agam, Daniel Rasche, Markus Köhli, Lasse Hertle, Solveig Landmark, Adit Arazi, Steffen Zacharias)

10:20 Discussion

 

10:30
Tea/Coffee break

Session 2

Chair: Daniel Rasche

11:00 A comprehensive evaluation of neutron monitor based cosmic ray flux corrections for CRNS (Lasse Hertle, Steffen Zacharias and Martin Schrön)

11:20 Incoming Neutron Flux Correction: an empirical approach to determining the site-specific correction parameter (Jonathan Evans and the whole COSMOS-UK Team)

11:40 A new ground level neutron monitor for the United Kingdom (Michael Aspinall, Tilly L. Alton, Cory L. Binnersley, Steven C. Bradnam, Carlo Cazzaniga, Stephen Croft, Christopher Frost, Malcolm J. Joyce, Dakalo Mashao, Lee W. Packer, Tony Turner and James A. Wild)

12:00 CRNS Networks for Space Weather: Progress and Challenges (Fraser Baird, Keith A Ryden, Fan Lei and Clive Dyer)

12:20 Discussion

 

12:30
Lunch

Session 3

Chair: Mie Andreasen

14:00 Keynote: Effect of Biomass Water Dynamics in Cosmic-Ray Neutron Sensor Observations: A Long-Term Analysis of Maize-Soybean Rotation in Nebraska (Tanessa Morris, Trenton Franz and Sophia Becker)

14:30 Using cosmic-ray neutron sensing for monitoring plant traits (Heye Reemt Bogena, C. Brogi, J. Jakobi, J. A. Huisman, J. Bates, C. Montzka and M. Schmidt)

14:50 Use of satellite-based vegetation indices and thermal neutron intensities to investigate biomass effects on roving CRNS measurements (Cosimo Brogi, H. R. Bogena, E. Capitanio, A. D. Rocha, F. Nieberding and J. A. Huisman)

 

15:10
Tea/Coffee break

Session 4

Chair: Jonathan Evans

15:40 Evaluating the effect of cover crops on soil hydrology in orchards using cosmic ray sensors (Isaya Kisekka, Srinivasa Peddinti, Charlie Chen, Anish Sapkota and Mathew Roby)

16:00 Evaluating seasonal soil water storage in an irrigated cropped field using cosmic-ray neutron sensing and soil hydrological modelling (Lena Scheiffele, Katya Dimitrova-Petrova, María Olivia García Quiroz and Sascha E. Oswald)

16:20 Next Generation Soil Moisture and Snow Water Equivalent Monitoring Using Cosmic Ray Neutron Sensing by the U.S. Geological Survey (Todd Caldwell, Gwendolyn Davies, Trenton Franz, Brandon Fleming, Robert Lotspeich, Shawn Naylor, Meredith Reitz, Graham Sexstone, Michelle Stern and Brian Pellerin)

16:40 Discussion

 

Conference Dinner

 

18:30
Dinner with live traditional Irish music
The Plough Inn, Hillsborough, BT266AG

Wednesday, Sept 25

Session 5

Chair: Martin Schrön

09:00 Keynote: Boron Based Neutron Sensing in COSMIC-SWAMP (Patrick Stowell on behalf of the COSMIC-SWAMP collaboration)

09:30 Development of a site-specific standardised Cosmic Ray Neutron Sensor (CRNS) calibration protocol (Konstantin Shishkin, Owen Fenton, Klara Finkele, Tamara Hochstrasser and Paul Murphy)

09:50 A Hydrus-1D model to harmonise soil moisture measurement scales from cosmic-ray neutron sensing to point sensors: application to COSMOS-UK data validation and quality assurance (Tim Howson, Sadra Emamalizadeh, Jonathan Evans, Gabriele Baroni and Philip Vincent)

10:10 Using cosmic-ray neutron measurements to validate gamma-ray spectrometry soil moisture estimation at three landcover types (Mie Andreasen, Steven Van der Veeke, Han Limburg, Ronald Koomans and Majken C. Looms)

 

10:30
Tea/Coffee break

Session 6

Chair: Cosimo Brogi

11:00 Sensing Arctic Snow: First insights into calibrating a Cosmic Ray Neutron Sensor on the Archipelago of Svalbard for Snow Water Equivalent monitoring (Nora Krebs, Paul Schattan, Martin Schrön, Lasse Hertle, Julia Boike, Sebastian Westermann, Marco Mazzolini, Clarissa Willmes, Simon Filhol, Christine Fey, Solveig Landmark, Steffen Zacharias and Peter Dietrich)

11:20 Simultaneous measurement of Snow Water Equivalent by cosmic neutrons and muons detection (Enrico Gazzola, Luca Stevanato, Mauro Valt, Stefano Gianessi, Barbara Biasuzzi, Luca Morselli, Marcello Lunardon and Federica Lorenzi)

11:40 Spatial and temporal variation of soil water content by cosmic-ray neutron sensors in Mediterranean agroecosystems (Leticia Gaspar Ferrer, Ana Navas and Trenton E. Franz)

12:00 Large-scale soil moisture monitoring using multiple rail-based cosmic-ray neutron systems: challenges and opportunities for an automatic CRNS roving network (Daniel Altdorff, Sascha E. Oswald, Solveig Landmark, Steffen Zacharias, Peter Dietrich, Sabine Attinger and Martin Schrön)

 

Field trip

Glenwherry, Cosmos UK site, including packed lunch

 

14:00 Overview of work at the CAFRE Hill Farm (Nicola Warden, CAFRE)

14:30 Site visit of the COSMOS-UK station

15:30 Afternoon tea/coffee and scones back at the centre

16:00 Carbon flux surveillance in the uplands of Northern Ireland (Phil Jordan, Ulster University)

16:20 Monitoring the Carbon and Water Balance of Peatlands in NI (Eimear Reeve, NI Environment Agency)

16:40 Peat NI - An investigation of emission factors for high organic matter soils managed as intensive grassland in Northern Ireland (Suzanne Higgins, AFBI)

17:00 Depart Glenwherry

18:00 Dinner as part of the field trip at Tullyglass Hotel, Ballymena Co Antrim BT421HJ

21:00 Arrival back in Hillsborough

 

Thursday, Sept 25

Session 7

Chair: Steffen Zacharias

09:30 Keynote: Getting Successful Impact in Weather Forecasting, Farming and Environmental Risks using CRNS Soil Moisture Observations (Jonathan Evans)

10:00 The Irish Soil Moisture Observation Network (ISMON): Inter-Institutional Collaboration to Establish Long-Term Infrastructure (Klara Finkele and ISMON Team)

10:20 Integration of soil moisture measurements into the observation network of the German Meteorological Service – the project IsaBoM (Mathias Herbst, Mario Albert, Leonhard Hufnagl, Wolfgang Kurtz and Jan Lenkeit)

10:40 Establishing Ground Referencing Network through the Korean cOsmic-ray Soil Moisture Observing System (KOSMOS) for Integrating Satellite Images (Jaehwan Jeong, Kiyoung Kim and Hyungsuk Kimm)

 

11:00
Tea/Coffee break

Session 8

Chair: Rafael Rosolem

11:30 COSMOS-UK Operations – Network Standardisation to deliver over 10 years of near real time soil moisture and hydrometeorological data (Phil Vincent and COSMOS-UK Team)

11:50 Advancing CRNS Processing: Towards Long-Term, Sustainable Research Tools (Daniel Power, Steffen Zacharias, Fredo Erxleben, Thomas Förster, Rafael Rosolem and Martin Schrön)

12:10 Discussion

 

12:30
Lunch

Session 9

Chair: Heye Reemt Bogena

13:30 Recharge modelling using in a semi-arid tropical watershed (Deepti B Upadhyaya, Rajsekhar Kandala, Laurent Ruiz, Jonathan Evans, Ross Morrison and Sekhar Muddu)

13:50 Role of infiltration on land–atmosphere feedbacks in Central Europe: WRF-Hydro simulations evaluated with cosmic-ray neutron soil moisture measurements (Joël Arnault, Benjamin Fersch, Martin Schrön, Heye Reemt Bogena, Harrie-Jan Hendricks Franssen and Harald Kunstmann)

14:10 Future increases in soil moisture drought frequency at UK monitoring sites: merging the JULES land model with observations and convection-permitting UK Climate Projections (Magdalena Szczykulska, Chris Huntingford, Elizabeth Cooper and Jonathan G. Evans)

 

14:30
Tea/Coffee break

Session 10

Chair: Klara Finkele

15:00 Keynote: From Research to Operations – The Next Steps from a National Meteorological Service Point of View (Eoin Moran, Klara Finkele, Padraig Flattery, Sarah Gallagher, Haleh Karbala Ali, Sarah O’Reilly and Saji Varghese)

15:30 Project SoMMet - Soil Moisture Metrology (Miroslav Zboril, María de los Ángeles Millán Callado and the SoMMet Consortium)

15:50 European and Global Environmental Research Infrastructures – key partners towards a global CRNS network (Steffen Zacharias and Daniel Power)

16:10 Towards the establishment of a global COsmic-ray Soil Moisture Observing System (Rafael Rosolem and Global COSMOS team)

16:30 Plenary discussion (moderated by Rafael Rosolem)

 

17:00
Closing

Friday, Sept 27

10:00
Guided tour of Hillsborough Castle (optional)
Meeting at the gates, opposite The Plough Inn.

 

​

Abstracts

 

Tuesday, Sept 24

Session 1

 

09:10 Keynote: The physics of Cosmic-Ray Neutron Sensing: Neutron evaporation and propagation at the land atmosphere interface
Jannis Weimar
(Physikalisches Institut, University of Heidelberg, Germany)

Particle simulations are the key tool to visualize and analyse the neutron creation and propagation for describing how Cosmic-Ray Neutron Sensing works. These toolkits from nuclear and particle physics precisely track the cosmic-ray neutron flux at the land-atmosphere interface in various different environmental settings. Therefore, they offer a comprehensive description of the neutron transport dynamics that also includes the creation of neutrons by particles other than neutrons. While this complete description helps to analyse the albedo epithermal neutron flux, it also opens the path for applications that use cosmic-ray neutrons as a proxy beyond typical CRNS.

We present conceptual simulation studies using the MCNP multi-particle code. MCNP6 offers a variety of different models that simulate high-energy interactions which create neutrons down to the thermal regime. Comparing MCNP simulations for water or various soil and air conditions with experimental data enables adapting of these models to specific scenarios such as neutron flux attenuation as a combination of production, propagation and absorption. Understanding all three of these contributors separately finally allows to reproduce experimental data and is a prerequisite for moving on to more complex and heterogeneous setups.

We show which cosmogenic particle species play a key role for neutron production and how various environmental conditions influence these processes. The results are used to improve effective neutron production modeling in the neutron-only simulation toolkit URANOS. Furthermore, this yields additional insights into the barometric correction function, snow-water-equivalent monitoring with below-snow neutron detectors as well as passive soil moisture sensing in the vadose zone via in-soil cosmic-ray neutrons flux measurements.

 

09:40 Response of bare and moderated neutron detectors under different environmental conditions
Daniel Rasche1, Martin Schrön2, Jannis Weimar3, Markus Köhli3,4, Theresa Blume1 and Andreas Güntner1,5
(1: Section Hydrology, GFZ German Research Centre for Geosciences, 14473 Potsdam, Germany, 2: Department of Monitoring and Exploration Technologies, Helmholtz Centre for Environmental Research – UFZ, 04318 Leipzig, Germany, 3: Physikalisches Institut, Heidelberg University, 69120 Heidelberg, Germany, 4: Physikalisches Institut, University of Bonn, 53115 Bonn, Germany, 5: Institute of Environmental Sciences and Geography, University of Potsdam, 14476 Potsdam, Germany)

Cosmic-Ray Neutron Sensing (CRNS) for the estimation of soil moisture relies on the detection of hydrogen-sensitive neutrons in the epithermal energy range. These are commonly measured using a moderated neutron detector shielded with a 25 mm high-density polyethylene shield which slows down epithermal neutrons to detectable energies. Many commercially available CRNS detector systems also include an unshielded, bare neutron detector for detecting slower thermal neutrons. Thermal neutrons are in equilibrium with the energy (temperature) of the surrounding media and compared to epithermal neutrons, different physical processes become important. This suggests a different response of thermal neutrons to changes in environmental hydrogen content and make thermal neutron a potentially useful variable to observe. Since the introduction of CRNS, different studies also consider thermal neutrons by modelling their response to different environmental conditions in neutron transport simulations and investigate the potential of thermal neutrons for estimating biomass and snow water equivalents.

In studies investigating thermal neutrons with neutron transport simulations, an energy threshold (e.g. < 0.5 or < 0.25 eV) is often used to define and subsequently analyse model results. However, at most observation sites, a regular bare neutron detector is used to observe thermal neutrons. As neutron signals observed by the bare and moderated neutron detector always contain a fraction of epithermal and thermal neutrons, respectively, a discrepancy between modelling studies and field observations exists. This reduces the transferability and knowledge gained from neutron transport simulations to better understand neutron observations.

Against this background, we used the URANOS model code to derive response functions of a bare and a moderated neutron detector. These mimic the behaviour of a real bare and moderated neutron detector and make neutron transport simulation results more comparable to field observations. The derived detector response functions were then used in a large set of neutron transport simulation scenarios including different soil moisture states, soil chemical properties, soil bulk densities, water and vegetation layers. The conducted neutron transport simulations provide valuable insights into the behaviour of bare and moderated neutron detectors and help to explain and gain further understanding of observed neutron signals at different study sites.

 

10:00 Pushing the limits of COSMOS: monitoring water content in deserts, complex terrain, and airships
Martin Schrön, Nurit Agam, Daniel Rasche, Markus Köhli, Lasse Hertle, Solveig Landmark, Adit Arazi, Steffen Zacharias
(1: Helmholtz Centre for Environmental Research GmbH, UFZ Leipzig, Germany, 2: Ben-Gurion University of the Negev, Israel)

The precise measurement of soil water content is a technological challenge. Traditional electromagnetic or remote-sensing approaches exhibit a range of problems, such as not covering the small-scale spatial heterogeneity of the lanscape, sensing only shallow soil horizons, exhibiting strong sensitivity to temperature, or losing accuracy under extremely dry conditions. A new approach based on cosmic-ray neutron sensing technology (CRNS) has promised to address most of these issues. Most studies in the past have investigated the practical use of CRNS instruments for soil moisture monitoring in mid-latitude regions, under semi-arid to humid conditions, and in the context of agriculture. In has been unclear for a long time how the sensor would perform under extreme conditions, such as desert environments, above pure-water bodies, or in complex terrain. Moreover, mobile CRNS surveys reached the limit of road accessibility and constrained footprint area. In this presentation, we will explore recent experiments and future applications of CRNS to push the existing limits of this technology. We will discuss the potential and limitations of CRNS to measure water content in the desert of the Negev, to monitor atmospheric variations with a buoy on a lake, and the influence of spatial heterogenity in the footprint. Furthermore, we will look at first experiments using airborne neutron sensing that extends the application domain into the third dimension.

Session 2

11:00 A comprehensive evaluation of neutron monitor based cosmic ray flux corrections for CRNS
Lasse Hertle, Steffen Zacharias and Martin Schrön
(Helmholtz Centre for Environmental Research - UFZ)

Correcting for the variability in cosmic ray flux for Cosmic Ray Neutron Sensing using neutron monitor data presents two challenges. These are caused by the two influences that the correction addresses: changes in the heliosphere and the effect of geomagnetism. For any neutron monitor based correction, it is first necessary to extract a clean signal for the changes in heliospheric modulation of cosmic rays from one or multiple monitors. In practice, this is challenged by the sensitivity of neutrons measured to hydrogen abundance near the detector. This sensitivity is dependent on the energy band of neutrons measured, with cascade neutrons being the least sensitive. Still, they are not free from the hydrogen influence, large snow accumulations or seasonal monsoon rains can skew the signal. Furthermore, technical difficulties or other structural changes to the neutron monitor will have a strong influence on the data. This makes the selection and screening of the neutron monitor data a critical endeavour. Secondly, the signal has to be localised to the site where the CRNS detector is installed, since the neutron monitor signal represents the geomagnetic conditions at the specific point on earth. The localisation mainly depends on altitude and cut-off rigidity. Multiple corrections have been put forward with differing attention to the challenge of localisation, but all based on a single neutron monitor. These correction methods have been compared among each other and to a novel approach based on multiple neutron monitors with the goal of evaluating the best suited correction method for any CRNS measurement.

 

11:20 Incoming Neutron Flux Correction: an empirical approach to determining the site-specific correction parameter
Jonathan Evans and the whole COSMOS-UK Team
(UK Centre for Ecology & Hydrology, Wallingford, Oxfordshire, OX10 8BB, UK)

Established methods to account for changes in naturally occurring ground level neutron flux, are applied to Cosmic Ray Neutron Sensor (CRNS) data, to enable accurate retrieval of soil moisture measurements. Common practice is to use standardised Neutron Monitors which are in operation around the world. However, there are relatively few Neutron Monitors, meaning that CRNS sensors may be far from the nearest monitor, thus changes in the incoming neutron flux based on Neutron Monitor changes need a site-specific parameter. This correction parameter also accounts for altitudinal differences and potentially it could account for differences in neutron energies measured by the Neutron Monitor compared with the CRNS.

Here we present the empirical approach applied to the COSMOS-UK network, to determine the site-specific incoming neutron correction factor, which we term ‘gamma’. This method relies on years of site specific CRNS data, during which there are significant changes in incoming neutron flux (i.e. more active years of the 11-year solar cycle). By selecting periods of most stable soil moisture content (such as winter periods around field capacity, for the UK), we determine the relationship between the site ground level neutron flux (as recorded by the CRNS) and the NM.

The resulting corrections remove trends in the soil moisture measurements which were correlated with NM trends. At some higher latitude wetter sites this correction has a high impact on the resulting data, which would otherwise be strongly biased and physically unreasonable. We compare this empirical approach to recently published methods to predict a priori the correction parameter and discuss possible reasons why the methods may lead to different results.

 

11:40 A new ground level neutron monitor for the United Kingdom
Michael Aspinall1, Tilly L. Alton1, Cory L. Binnersley2, Steven C. Bradnam3, Carlo Cazzaniga4, Stephen Croft1, Christopher Frost4, Malcolm J. Joyce1, Dakalo Mashao1, Lee W. Packer3, Tony Turner3 and James A. Wild5
(1School of Engineering, Lancaster University, Lancaster, United Kingdom, 2Mirion Technologies (Canberra UK) Limited, Warrington, United Kingdom, 3United Kingdom Atomic Energy Authority, Abingdon, United Kingdom, 4STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, United Kingdom, 5Physics Department, Lancaster University, Lancaster, United Kingdom)

We provide an update on a new ground level neutron monitor (NM) for space weather observations. Such monitors operate in a global network to deduce the primary cosmic ray (CR) flux in the upper atmosphere from measurements of CR variations and fluxes of solar energetic particles at the Earth’s surface. The current network has been operational since the 1960’s and consists of about fifty NMs, most are implemented to the 1964 standard devised by Carmichael – the NM-64. The NM-64 uses large boron trifluoride (BF3) gas filled proportional counter tubes in configurations of 3, 6, 9 or 18 tubes. The instruments work on the production of fast neutrons via spallation within a lead (Pb) producer, moderation of the produced neutrons to thermal energies via a high-density polyethylene (HDPE) moderator, and thermal neutron detection using gas-filled proportional counters. NM-64s are massive and expensive, rely on highly toxic gas and can be temperamental due to the age of their counting electronics. After evaluating various detector options, based on operational experience, experiments and simulations, a new NM design was conceived which exploits the established supply chain serving nuclear safeguards and security. The new slab design is optimised for 1” dia., helium-3 (3He) gas-filled proportional counters, it has a 64% smaller footprint, 80% smaller volume, 55% less mass and is estimated to be cheaper than the present-day build costs of a 6-tube NM-64. Various experimental results are in good agreement with our Monte Carlo simulations used for design optimisation. CR neutron detectors are used worldwide for monitoring soil moisture (e.g., COSMOS-UK) and are highly dependent on incoming CRs, they therefore rely on NM data daily for data interpretation. Hence the relevance of this work to the soil moisture sensing community and for establishing national and continental sensor networks for long-term environmental and space weather observation.

 

12:00 CRNS Networks for Space Weather: Progress and Challenges
Fraser Baird, Keith A Ryden, Fan Lei and Clive Dyer
(Surrey Space Centre, University of Surrey)

Enhancements to atmospheric radiation caused by space weather events are a significant hazard to aviation. Typically, such enhancements are monitored by the ground level neutron monitor network. However, this network is sparse and ageing. The density of CRNS networks worldwide means that such networks have strong potential for observing these enhancements alongside neutron monitors. In this contribution, an overview of recent progress towards realising this potential will be presented. Specifically, the results of searches for space weather signals in COSMOS-UK data, as well as the yield functions for CRS/2000B detectors will be outlined.  Outstanding questions and challenges will also be discussed.

Session 3

14:00 Keynote: Effect of Biomass Water Dynamics in Cosmic-Ray Neutron Sensor Observations: A Long-Term Analysis of Maize-Soybean Rotation in Nebraska
Tanessa Morris, Trenton Franz and Sophia Becker
(School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE, USA)

The precise measurement of soil water content (SWC) is crucial for effective water resource management. This study utilizes the Cosmic Ray Neutron Sensor (CRNS) as a novel technique for area-averaged SWC measurements at an intermediate scale. However, accurate SWC measurements from CRNS require consideration of all hydrogen sources, including time-variable ones like plant biomass and plant water. Near Mead, Nebraska, three field sites (CSP1, CSP2, and CSP3) growing a maize-soybean rotation have been monitored for 5 (CSP1 and CSP2) and 13 years (CSP3), collecting data on biomass water equivalent (BWE) biweekly with destructive sampling, epithermal neutron counts, atmospheric variables, and point-scale SWC from a sparse Time Domain Reflectometry (TDR) network (4 locations and 5 depths). In 2023, dense gravimetric SWC surveys were collected 8 times in each field over the growing season The N0 parameter, derived from the Desilets Equation, exhibits a strong linear relationship with BWE, suggesting a straightforward vegetation correction factor (fveg). Results from both the 2023 gravimetric surveys and long-term TDR data indicate a count rate reduction of 1% (+/- 0.5%) for every 1 kg/m2 (or mm of water) increase in biomass for all 3 sites and 2 crop types. This reduction factor aligns well with existing but shorter-term studies in croplands and forests. The higher count rate detector model CRS2000B model at CSP1 and CSP2 significantly reduced the uncertainty in the results (R2 of 0.8 vs. 0.3) compared to the CRS 1000B model at CSP3. This research strongly supports an fveg correction should be applied for cropland sites. It is also likely the same fveg correction can be applied to forest sites, but a long-term study is still needed. This long-term study contributes valuable insights into the vegetation correction factor for CRNS, helping resolve a long-standing issue within the CRNS community.

 

14:30 Using cosmic-ray neutron sensing for monitoring plant traits
Heye Reemt Bogena, C. Brogi, J. Jakobi, J. A. Huisman, J. Bates, C. Montzka and M. Schmidt
(Agrosphere Institute (IBG-3), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany)

Continuous information on plant traits such as plant height (PH) and leaf area index (LAI) is important to study and monitor plant growth with positive impacts on sustainable agriculture as well as crop and land surface model development. Cosmic-ray neutron sensors (CRNS) have primarily been used to determine soil moisture but have potential in vegetation and plant traits monitoring. Here, long-term CRNS, PH, and LAI data (2015-2023) from an agricultural field with different crops (Selhausen, Germany) were used to test such potential. Thermal neutron intensity was used to predict PH and LAI via regression models of in-situ measurements with additional validation from Unmanned Aerial System (UAS)-based LiDAR and multispectral data. For PH, the annual models provided generally high R2-values (0.86 on average) while an aggregation by crop type resulted in a slight reduction of the R2-values (0.77 on average). The distinct differences in the observed slope values support the assumption that plant traits – thermal neutron intensity relationships depend on vegetation structure. The root mean square error (RMSE) of the PH predicted with thermal neutron intensities was between 12 and 14 cm. A regression model to predict LAI based on PH was then established (R2: 0.78) and used to predict LAI with thermal neutron intensity for the 2019-2013 period. The resulting RMSE was 0.91 for potato and 1.25 for sugar beet, which is within the uncertainty range of radiation-based methods. In the case of winter wheat, however, the RMSE was a relatively high 3.12 with overestimations in dry seasons and underestimations in wet seasons. Validation against UAS-based PH and Green Area Index (GAI) generally confirmed the results although GAI and LAI in winter wheat were comparable only before the onset of senescence. These results demonstrate the potential of CRNS for continuous monitoring of plant traits at the field scale.

 

14:50 Use of satellite-based vegetation indices and thermal neutron intensities to investigate biomass effects on roving CRNS measurements
Cosimo Brogi1, H. R. Bogena1, E. Capitanio1,2, A. D. Rocha3, F. Nieberding1 and J. A. Huisman1
(1: Agrosphere Institute (IBG-3), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany, 2: Department of Physical Sciences, Earth and Environment, University of Siena, 53100 Siena, Italy, 3: Geoinformation in Environmental Planning Lab, Department of Landscape Architecture and Environmental Planning, Technical University of Berlin, 10623 Berlin, Germany)

The use of roving cosmic-ray neutron sensors (CRNS) can provide soil moisture (SM) information over large areas. These can be extremely useful, for example, in the validation of land-surface models and satellite-based SM products. However, there are challenges in roving CRNS applications that are not yet resolved. For instance, detailed biomass information is often needed to obtain accurate SM estimates. Between June and November 2023, five roving CRNS measurements were performed in the Selke River catchment (Saxony Anhalt, Germany) as part of a joint field campaign of the CosmicSense project. Over 1000 km of measurements were conducted with the FZJ rover (Hydroinnova LLC, Albuquerque, NM, USA) that was equipped with 36 detector tubes. Of these tubes, 20 were moderated by 25 mm high density polyethylene (HDPE) to measure neutrons in the epithermal energy regime while 16 tubes were left bare to shift the measured energy towards the thermal energy regime.

In addition, 19 stationary CRNS along different land covers of the study area were available for support. Four of these were CRS-2000 (Hydroinnova LLC, Albuquerque, NM, USA) equipped with moderated and bare detectors that were placed in agricultural areas. Vegetation indices such as NDVI were derived from Sentinel-2 satellite images at 10 m resolution to estimate/proxy biomass close to the roving dates. Additionally, land cover and land use information were used to stratify the study area into the most representative cover types.

The temporal and spatial relationships between satellite-based vegetation indices and thermal or epithermal neutron intensities were investigated. The SM estimated from epithermal neutrons was compared with data from the available stationary CRNS and from in-situ measurements and samples. It was then explored whether thermal neutron intensities can be used to improve roving SM estimates by providing on-the-fly corrections of epithermal measurements for the surrounding biomass.

Session 4

15:40 Evaluating the effect of cover crops on soil hydrology in orchards using cosmic ray sensors
Isaya Kisekka1,2, Srinivasa Peddinti1, Charlie Chen1, Anish Sapkota1,2 and Mathew Roby3
(1: University of California Davis, Department of Land, Air and Water Resources, 2: University of California Davis, Department of Biological and Agricultural Engineering, 3: USDA ARS Sustainable Agricultural Water Systems Research)

Cover crops can provide many agronomic benefits in nut orchards including improving soil health, providing habitats for pollinators, and increasing soil water storage. However, there is an urgent need to develop robust methods for evaluating the effectiveness of cover crops in altering soil hydraulic properties that govern soil water holding capacity. Cosmic ray soil moisture monitoring provides continuous, non-intrusive observations of shallow soil moisture across large areas. This study uses cosmic ray soil moisture data and the HYDRUS model to evaluate soil hydraulic properties in cover and non-cover cropped young pistachio orchards in California. We integrated experimental observations with the HYDRUS Module Cosmic to estimate changes in soil hydraulic properties through inverse modelling. A thorough examination was conducted, comparing the soil hydraulic properties estimated using cosmic ray soil moisture data with independent point scale measurements. There was a substantial difference in van Genuchten soil hydraulic properties in the cover versus non-cover cropped pistachio orchard in the shallow soil layers, which could be attributed to improved soil structure in the cover-cropped orchard. This study demonstrates a method for using cosmic ray soil moisture data with the Hydrus model to evaluate the effect of conservation practices, such as cover cropping, on soil hydraulic properties at field scale.

 

16:00 Evaluating seasonal soil water storage in an irrigated cropped field using cosmic-ray neutron sensing and soil hydrological modelling
Lena Scheiffele, Katya Dimitrova-Petrova, María Olivia García Quiroz and Sascha E. Oswald
(Institute of Environmental Science and Geography, University of Potsdam, Germany)

Brandenburg is one of the driest regions in Germany (average precipitation of 500 mm/year) with 45 % of its area used for agricultural production. The limited precipitation, alongside changing precipitation patterns and increasing temperatures attributed to climate change, makes agricultural production more vulnerable. In recent years, pronounced dry spells and drought periods during spring and summer posed additional risks to crop health and yield. Paired with the prevalence of sandy and sandy-loamy soils with low water holding capacity, the demand for irrigation is expected to rise, but will have to rectify its use of the also stressed subsurface and surface water resources. Therefore, optimizing irrigation practices is of great interest for stakeholders and root zone soil moisture monitoring and modelling can support decision-making.

In this study, we investigate the response of root zone soil water storage to irrigation in a cropped field in Oehna, Southern Brandenburg. A cosmic-ray neutron sensor (CRNS) is installed in the center of the field, with its horizontal footprint fully covered by the pivot irrigation system. Our aim is to evaluate how CRNS can contribute to assess the water balance for the crop season 2024 and to suggest improvements for irrigation to enhance crop yield. For this purpose we use >1.5 years of soil moisture data from CRNS and a soil moisture profile probe. We complement the monitoring with soil hydrological modeling (HYDRUS 1D) to comprehensively assess soil moisture dynamics. Model calibration is supported by CRNS data, irrigation amounts and collected crop biomass information. Additionally, we evaluate the effectiveness of a CRNS probe equipped with a single additional soil moisture profile sensor as a standalone setup in assessing soil moisture distribution within the root zone. Our findings contribute to improving irrigation practices by CRNS measurement, tailored to the local environmental conditions, ultimately fostering sustainable agricultural management, through optimal irrigation water use to support satisfactory crop yield.

 

16:20 Next Generation Soil Moisture and Snow Water Equivalent Monitoring Using Cosmic Ray Neutron Sensing by the U.S. Geological Survey
Todd Caldwell1, Gwendolyn Davies1, Trenton Franz2, Brandon Fleming3, Robert Lotspeich4, Shawn Naylor5, Meredith Reitz4, Graham Sexstone6, Michelle Stern7 and Brian Pellerin8
(1: Nevada Water Science Center, U.S. Geological Survey, Carson City, Nevada, United States, 2: University of Nebraska, Lincoln, Lincoln, Nebraska, United States, 3: Pennsylvania Water Science Center, U.S. Geological Survey, New Cumberland, Pennsylvania, United States, 4: Colorado Water Science Center, U.S. Geological Survey, Lakewood, Colorado, United States, 5: Ohio-Kentucky-Indiana Water Science Center, U.S. Geological Survey, Indianapolis, Indiana, United States, 6: California Water Science Center, U.S. Geological Survey, Sacramento, California, United States, 7: Hydrologic Remote Sensing Branch, U.S. Geological Survey, Reston, Virginia, United States 8: Hydrologic Networks Branch, U.S. Geological Survey, Reston, Virginia, United States)

The United States faces growing challenges in providing safe and sustainable water supplies for human and ecological uses. The U.S. Geological Survey (USGS) plays an essential role in meeting these challenges through its observational networks and water research activities. Emerging and innovative technologies in water science have led the USGS to develop the Next Generation Water Observing System (NGWOS) in ten planned pilot basins across the nation. The NGWOS aims to foster innovation and development of monitoring technologies and methodologies. Soil-water content (SWC) and snow water equivalent (SWE) are particularly difficult to quantify at appropriate scales for water-supply research. Traditional in situ sensors measure a limited area that reflects local (sub-meter) variability. More often, watershed-scale (1-100 square kilometers) estimates are needed to improve water-supply forecasting and groundwater recharge estimates. In collaboration with university and industry partners, NGWOS began a research and development program to evaluate novel technologies for measuring SWC and SWE, including cosmic ray neutron sensors (CRNS) which are now deployed at innovation test beds and in a pilot network. This presentation will describe USGS NGWOS activities for operationalizing CRNS and in situ SWC and SWE collection within the bounds of USGS data quality standards and policy. The goal of this research and development program is to expand CRNS monitoring to a national scale and to increase the adoption of such data into water availability assessments and water resource management.

Wednesday, Sept 25

Session 5

09:00 Keynote: Boron Based Neutron Sensing in COSMIC-SWAMP
Patrick Stowell on behalf of the COSMIC-SWAMP collaboration
(Physics & Astronomy Department, University of Sheffield, Sheffield, S10, 2TN, United Kingdom)

The COSMIC SWAMP project aims to develop tools for improving irrigation efficiency through the use of boron-based cosmic neutron sensors for continuous soil moisture monitoring. These sensors use cosmic-ray neutron sensing to produce rolling soil moisture estimates in COSMIC-SWAMP, that can be used directly with automated crop modelling tools to understand water resource management. In this presentation, we will discuss the creation and testing of low-power neutron detectors that are capable of transmitting data via LoRaWAN, enabling their integration into existing smart farm sensing networks. A significant focus will be on developing a low-power pulse shape discrimination module to enable effective neutron-gamma discrimination in scintillator-based neutron detectors in the field. Following this we will review efforts to test these sensors at a field site in the UK alongside lessons learnt deploying them in an existing smart farm sensor field site in Brazil.

 

09:30 Development of a site-specific standardised Cosmic Ray Neutron Sensor (CRNS) calibration protocol
Konstantin Shishkin1,2, Owen Fenton2, Klara Finkele5, Tamara Hochstrasser4,3 and Paul Murphy1,3
(1: UCD School of Agriculture and Food Science, University College Dublin, Dublin 4, Ireland, 2: Teagasc, Environmental Research Centre, Johnstown Castle, Wexford, Ireland. 3: UCD Earth Institute, University College Dublin, Dublin 4, Ireland, 4: UCD School of Biology and Environmental Science, University College Dublin, Dublin 4, Ireland, 5: Met Éireann, Glasnevin, Dublin 9, Ireland)

Soil moisture is a key soil characteristic that must be taken into account when planning agricultural

management activity e.g. trafficking of land or timing of nutrient application. Traditionally, soil moisture is measured using point-scale sensors or directly through field sampling followed by drying-weighing of the soil sample in the laboratory. However, due to the spatial heterogeneity of soils, the amount of soil moisture may vary significantly within even a few meters within a single paddock, which limits the usefulness of the traditional point-scale methods for management decisions. In contrast, satellite measurements of soil moisture are too coarse in their resolution to give accurate descriptions of soil moisture at the field scale. The Cosmic-Ray Neutron Sensor (CRNS) is a neutron sensing instrument that can be installed at field sites to monitor soil moisture conditions over intermediate scales. This approach uses the principle of elementary particle attenuation with depth to assess concentration of water molecules in soil within a footprint of 75-300 m radius, with a varying accuracy for the chosen footprint radius. Further exploration of both the CRNS footprint and accuracy is needed, necessitating the development of a standardized site-specific calibration process (the ocus of the present work) to enable enhanced data integration across sites and improve the accuracy of neutron counts (NC) to volumetric soil moisture content (VMC) conversion within the defined footprint. For that purpose, the newly established Irish Soil Observation Network (ISMON) has installed ten CRS2000/B neutron sensors presenting an opportunity to create such a standardised protocol. This work presents the first results of the ISMON CRNS stations calibration and introduces a new vision towards development of standardised CRNS calibration protocol for grassland sites.

 

09:50 A Hydrus-1D model to harmonise soil moisture measurement scales from cosmic-ray neutron sensing to point sensors: application to COSMOS-UK data validation and quality assurance
Tim Howson1, Sadra Emamalizadeh2, Jonathan Evans1, Gabriele Baroni2 and Philip Vincent1
(1: UK Centre for Ecology and Hydrology, Wallingford, UK; 2: University of Bologna, UK.)

The World Meteorological Organisation’s (WMO) Global Climate Observing System (GCOS) includes soil moisture as one of the Essential Climate Variables (ECV). Soil moisture is particularly important for agricultural applications, hydrological modelling, weather forecasting, and studying the effects of climate change. However, there are different in-situ measurement techniques with different sensor footprints and different sources of error, which can make comparisons and validation difficult. Point-scale sensors typically have a small, decimetre footprint and require careful installation for measurements to be representative. Cosmic-ray neutron sensing (CRNS) techniques can cover a 200 m radius but relatively shallow depths, mostly influenced by the water content of the top 10 cm of soil (unless very dry). The COSMOS-UK network uses the CRNS technique to measure soil moisture from 47 currently active sites throughout the UK. Calibration coefficients are calculated from soil calibrations using traditional invasive soil sampling at each site, followed by laboratory methods measuring gravimetric soil moisture, lattice-bound water, bulk density, and soil organic carbon. In addition, most COSMOS-UK sites have Time Domain Transmissometer (TDT) point soil moisture sensors at 5, 10, 15, 25, and 50 cm depths in two replicates (a total of ten sensors). Since the CRNS technique is relatively new, open questions, e.g., incoming neutron correction, require independent soil moisture measurements. Therefore, there is a strong need to be able to directly compare and cross-validate CRNS measurements with TDT soil moisture measurements whilst properly accounting for their different spatial scales, including depth. This paper discusses the application of the Hydrus-1D model for validation and quality assurance of different COSMOS-UK soil moisture measurements at the field and point scales. The resulting measurement harmonisation is part of a developing framework for the EURAMET project on Soil Moisture Metrology (SoMMet).

 

10:10 Using cosmic-ray neutron measurements to validate gamma-ray spectrometry soil moisture estimation at three landcover types
Mie Andreasen1, Steven Van der Veeke2, Han Limburg2, Ronald Koomans2 and Majken C. Looms3
(1: Geological Survey of Denmark and Greenland, Denmark, 2: Medusa Radiometrics, Groningen, Skagerrak 26, 9723 JR, Groningen, the Netherlands, 3: Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark)

Soil moisture measurements can be used to provide early warning of an emerging drought. Droughts during the growing season may result in loss of agricultural yield but can also affect the natural ecosystems negatively or cause damages to infrastructure. Furthermore, when the soil becomes saturated additional rainfall may not infiltrate fast enough and the excess water will produce increased quick flow with risk of flooding both locally and at downstream locations. In the recent years both droughts (summers 2018 and 2023) and flooding events (winters 2019/2020 and 2023/2024) have had large economic consequences. Soil moisture can vary considerably over short distances because of its dependency on vegetation, root uptake of water, local slopes and terrain, and soil structure and soil composition. As a result, it is difficult to obtain a precise understanding of soil moisture dynamics of a specific land cover from only a few point-scale sensors.

In order to account for this variability, methods for estimating area-average soil moisture are therefore paramount to accurately assess and understand the water budget for different landcover types. For the last decade, the cosmic-ray neutron (CRN) detector has been used for soil moisture estimation at a spatial scale of hundreds of meters. However, this scale is insufficient for small agricultural fields (<1-2 ha) and precision agriculture practices (e.g., irrigation scheduling) that require more localized soil moisture data. Recently, stationary gamma-ray spectrometry (GRS) detection was introduced in the field of hydrology for continuous soil moisture estimation at a unique spatial scale of 10s-of-meters.

In this study, we test the GRS soil moisture method for an agricultural field, a beech forest, and a spruce plantation. We examine the correlation between CRN intensities and GRS concentrations at each site and evaluate the performance of three GRS soil moisture conversion functions. While we observe a strong correlation between CRN intensities and GRS concentrations for all sites, challenges arise with the CRN conversion function in forested areas. The function's shape does not appropriately capture the soil moisture dynamics. This study highlights the need for further refinement of the conversion methods to improve the accuracy of the soil moisture estimates, particularly in complex land cover types like forests.

Session 6

11:00 Sensing Arctic Snow: First insights into calibrating a Cosmic Ray Neutron Sensor on the Archipelago of Svalbard for Snow Water Equivalent monitoring
Nora Krebs1, Paul Schattan1,2, Martin Schrön3, Lasse Hertle3, Julia Boike4, Sebastian Westermann5, Marco Mazzolini5, Clarissa Willmes5, Simon Filhol5, Christine Fey1,2, Solveig Landmark3, Steffen Zacharias3 and Peter Dietrich3
(1: Institute of Geography, University of Innsbruck, 6020 Innsbruck, Austria, 2: Institute of Hydrology and Water Management (HyWa), University of Natural Resources and Life Sciences, 1190 Vienna, Austria, 3: Department of Monitoring and Exploration Technologies, Helmholtz Centre for Environmental Research - UFZ Leipzig, 04318 Leipzig, Germany, 4: Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany, 5: Department of Geosciences, University of Oslo, 0316 Oslo, Norway)

Throughout the last decades air temperature measurements revealed that the Arctic shows the highest warming trend on Earth, inducing fast changes on snow cover dynamics. Because of the remoteness of arctic research sites, additional information needs to be obtained from satellite observations and snowpack models. While in-situ snow measurements provide valuable data to set up and validate snow models and remote sensing products, the small spatial footprint of the former commonly mismatches the coarse spatial resolution of the latter, introducing uncertainty.

Above-snow Cosmic Ray Neutron Sensing (CRNS) is an emerging technique for the observation of the Snow Water Equivalent (SWE) that may overcome this scale gap. The measurement principle of CRNS is based on the moderation of cosmogenic neutrons by hydrogen atoms. The characteristic scattering length of neutrons in the Earth ́s atmosphere results in an integrated footprint size of several hectares that matches the spatial resolution of most remote sensing products and distributed snow models. However, up to this point the method has never been tested at arctic latitudes.

In July 2023, we installed a CRNS detector at the AWIPEV long-term observation site Bayelva in Ny-Ålesund, Svalbard. We thereby present first insights into the calibration of the above-snow CRNS detector for arctic SWE observations. The calibration has been performed by distributed snow height and density measurements. Control on dynamics in the resulting SWE signal is provided by complementary continuous snow measurements at the Bayelva research site. The application of above-snow CRNS on arctic snow cover holds numerous assets and has the potential to benefit snow monitoring at arctic latitudes as a whole.

 

11:20 Simultaneous measurement of Snow Water Equivalent by cosmic neutrons and muons detection
Enrico Gazzola1, Luca Stevanato1, Mauro Valt2, Stefano Gianessi1, Barbara Biasuzzi1, Luca Morselli1, Marcello Lunardon1,3 and Federica Lorenzi1
(1: Finapp srl, via del Commercio 27, Montegrotto Terme (Italy), 2: Regional Agency for Environmental Prevention and Protection of Veneto (ARPAV) - Italy, 3: Dept. of Physics and Astronomy "Galileo Galilei", University of Padova, Italy)

The amount of water stored in mountain snowpack as Snow Water Equivalent (SWE) is a fundamental part of the water resource. Despite its relevance, its monitoring poses great challenges due to the remoteness and elevation of the areas of interest. While it is commonly measured through in-situ coring campaigns performed by specialized personnel, estimated by computational models relying on meteorological observations, or derived from satellite data, the limitations of these methods let us with the need of proximal sensors providing continuous SWE measurements in mountain areas.

Recently, probes based on the detection of cosmic rays have emerged as a suitable candidate, with the development of devices based on either the absorption of neutrons or muons by the snowpack. Finapp developed and patented a compact probe suitable for Cosmic-Rays Neutron Sensing applications, characterized by the unique feature of being able to detect and discriminate both neutrons and muons with the same detector.

The 2023/2024 winter season saw the activation of the first full nivological network of 20 Finapp probes across the mountain areas of the Veneto region (Italy), for the Regional Environmental Protection Agency of Veneto (ARPAV), at altitudes between 1400 and 2600 m asl. This offers a large test field for assessing the performances of the sensors and how they compare to available data from field campaigns, historical trends and computational models.

The setup for SWE measurements is composed by a Finapp probe in the ground, plus a reference detector on a mast, out of the snowpack, to monitor the incoming cosmic rays flux. SWE is calculated basing on the drop of either neutron counts or muons counts by the ground detector. The two methods will be compared, with a special attention to their notably different footprint, and the advantages of their simultaneous availability will be highlighted.

 

11:40 Spatial and temporal variation of soil water content by cosmic-ray neutron sensors in Mediterranean agroecosystems
Leticia Gaspar Ferrer1, Ana Navas1 and Trenton E. Franz2
(1Estación Experimental de Aula Dei (EEAD-CSIC). Consejo Superior de Investigaciones Científicas, Zaragoza, Spain, 2School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE, United States)

Accurate information of spatial and temporal variation of soil moisture is crucial for understanding the land surface processes and their management. Antecedent soil moisture can be one of the most important factors controlling hydrological and erosive processes, affecting the runoff and soil loss in agroforestry systems. In situ field measurements of soil moisture are restricted to discrete data at specific locations, while remote sensing products offered a coarse spatial and temporal resolution data limited to the soil surface. The use of Cosmic-ray neutron sensors (CRNS) for providing effective soil water content measurements at the field scale is a unique and increasingly accepted method used in a multitude of research applications over the past decade. This contribution details the successful application of a mobile "backpack" CRNS in a heterogeneous terrain of a Spanish agroforestry system to obtain SWC information at the field scale. Our results captured how soil moisture varies temporally and spatially along different seasonality conditions (late wet spring, dry and wet summer), in locations with certain land use (crops, pastures or Mediterranean forest) topography or soil properties. Our preliminary results indicate that CRNS captured soil moisture dynamics along the toposequence and demonstrated the sensitivity of neutron sensors to investigate the effect of parent material on soil water. Together with soil erosion rates estimated by 137Cs fallout, the combination of these nuclear techniques may result in a better understanding of how water content affects the process of soil degradation.

 

12:00 Large-scale soil moisture monitoring using multiple rail-based cosmic-ray neutron systems: challenges and opportunities for an automatic CRNS roving network
Daniel Altdorff1,3, Sascha E. Oswald1, Solveig Landmark2, Steffen Zacharias2, Peter Dietrich2,4, Sabine Attinger3,1 and Martin Schrön2
(1: Institute of Environmental Science and Geography, University of Potsdam, Potsdam, Germany; 2: Department for Monitoring and Exploration Technologies, UFZ — Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany, 3: UFZ Leipzig — Helmholtz Centre for Environmental Research GmbH, Department of Computational Hydrosystems, 4: Center for Applied Geoscience, University of Tübingen, Germany)

Soil water content (SWC) is one of the key variables controlling crucial environmental processes. While spatio-temporal information on soil moisture at large scales (1 to 100 km) is a prerequisite for a variety of applications and modeling efforts, its measurement in relevant soil depths and at a management-relevant scale and temporal resolution is still a challenge. Over the past decade, cosmic-ray neutron sensing (CRNS) has become a popular method for non-invasive SWC measurements. The lateral footprint extension in the hectare range with an integral depth of several decimeters and the maintenance-free data recording have made CRNS particularly popular. Mobile CRNS in cars, for instance, offers the possibility of mapping large areas, but requires manual operation (i.e., a driver). This limits the collected information to few campaign days. The recently introduced fully automatic rail-based system (Rail-CRNS) can overcome this limitation and is potentially capable of collecting continuous SWC information along the railroad. While a pilot project has demonstrated the feasibility along a 9 km long railroad line in central Germany, we present here the first results of a large-scale SWC monitoring measured by several Rail-CRNS systems across Germany. Up to five Rail-CRNS systems run simultaneously daily over several hundred kilometers and record the ambient neutrons and generate spatiotemporal SWC products from an area of more than 100 km2 nearly in real time. However, since a number of influencing factors affect the conversion of measured neutrons into in-situ SWC (e.g. driving speed, biomass, land use), efforts to correct and improve signal quality before conversion to SWC are still challenging. We discuss current approaches using practical examples and highlight their advantages and disadvantages. Finally, the next steps towards realizing the vision of a network that provides reliable SWC data in near real-time as a basis for decision-making for various applications will be outlined.

Thursday, Sept 25

Session 7

09:30 Keynote: Getting Successful Impact in Weather Forecasting, Farming and Environmental Risks using CRNS Soil Moisture Observations
Jonathan Evans
(UK Centre for Ecology & Hydrology, Wallingford, Oxfordshire, OX10 8BB, UK.)

Here we present a brief review of successful Cosmic Ray Neutron Sensor (CRNS) soil moisture data applications, and their impact, with a vision to increase the impact of soil moisture datasets. Some of the important steps for validation of the technique and development of soil moisture measurement standards are noted, as the foundation for data applications. An overview of some early work on applications such as remote sensing comparisons demonstrates the benefits of increased in situ observational scale along with open issues and challenges of matching measurement scales. Data assimilation and other approaches are now being used to calibrate both gridded land surface and hydrological models, with the drive towards continuous assimilation of ground-based soil moisture observations into operational weather, flood, drought and wildfire forecasting and warning systems. CRNS soil moisture datasets should play a critical role in delivering actionable end user information for more resilient flood, drought and water resource management in the context of a changing climate.

 

10:00 The Irish Soil Moisture Observation Network (ISMON): Inter-Institutional Collaboration to Establish Long-Term Infrastructure
Klara Finkele and ISMON Team
(Met Éireann, Glasnevin, Dublin 9, Ireland)

Real-time soil moisture measurements are essential for the dynamic management of climate change adaptation, reduction of nutrient losses and greenhouse gas emissions from agriculture and forestry. Soil moisture status influences crop growth, run-off, groundwater recharge, land surface-atmospheric exchange dynamics and greenhouse gas emissions as well as forest fire risk. Here we present the new Irish Soil Moisture Observation Network (ISMON) as an umbrella to bring together several recently established long-term environmental observational networks. These are: 1) initiative of the AGMET group, 2) COSMOS UK – Northern Ireland, 3) Teagasc NASCO (National Agricultural Soil Carbon Observatory) and 4) Terrain-AI, all of which include several different methodologies for measuring soil moisture. The AGMET initiative installed 10 new sites with CRNS (cosmic ray neutron sensors), whereas Teagasc NASCO and Terrain AI are using Time Domain Reflectometry probes. Such networks are seen as necessary to resolving the problem of scale between point, field-based measurements and satellite-derived soil moisture products and are important in monitoring key biogeochemical processes that vary rapidly in time and space. In the initial phase of the implementation of the ISMON network, the current distribution of the stations in relation to the other networks are presented. The ISMON aims to capture the most relevant soil types, land cover, and regional climate regimes to corroborate direct measurements of soil moisture and will adapt its design to improve the monitoring network as required. The ISMON will make a valuable contribution to, and expand the international soil moisture monitoring network.

 

10:20 Integration of soil moisture measurements into the observation network of the German Meteorological Service – the project IsaBoM
Mathias Herbst1, Mario Albert1, Leonhard Hufnagl1, Wolfgang Kurtz1 and Jan Lenkeit2
(1: German Meteorological Service (Deutscher Wetterdienst, DWD), Center for Agrometeorological Research, Braunschweig/ Freising, Germany, 2: German Meteorological Service (Deutscher Wetterdienst, DWD), Department Observation Networks and Data, Hamburg, Germany)

As many other European countries, Germany has been affected by an increasing number of both drought and flood events in the last couple of years that had considerable negative impacts on the agricultural and forestry sector. These events led to an increasing information demand of stakeholders, practitioners and the general public on critical variables such as soil moisture. Area-wide information on soil moisture is most often derived indirectly from hydrological model simulations, one of them being DWD’s soil moisture viewer which is based on the SVAT-model AMBAV. Besides model-based soil moisture information, which is strongly influenced by model assumptions and parameterisation, a number of institutions started to build-up local soil moisture observation networks, such as the TERENO network, that also provide in-situ observations of soil moisture states. However, a nationwide observation network for (standardised) soil moisture observations is still lacking in Germany.

The project IsaBoM (“Integration of standardised and automatized soil moisture measurements in the DWD observation network”), an internal project of the German Meteorological Service (DWD), strives to establish the technical and scientific basis for introducing standardised soil moisture observations in DWD’s operational meteorological observation network. This includes e.g. the choice of suitable sensors and measurement protocols, calibration procedures for selected sensors, quality-control measures and establishing data flow and automated data provisioning. The final goal is to equip about 25 stations throughout Germany with CRNS sensors and in-situ profile measurements of soil moisture where the chosen locations should provide a representative subset in terms of soil properties and climatic conditions. Here we present the overall network design as well as first comparisons between soil moisture data obtained by different CRNS sensors at two sites that have a broad range of complementary agrometeorological measurements in place that facilitate a thorough interpretation of the results.

 

10:40 Establishing Ground Referencing Network through the Korean cOsmic-ray Soil Moisture Observing System (KOSMOS) for Integrating Satellite Images
Jaehwan Jeong1, Kiyoung Kim2 and Hyungsuk Kimm3,4
(1: Agriculture-forestry Bioresources Convergence Center, Seoul National, University, Republic of Korea, 2: Survey planning department, Korea Institute of Hydrological Survey, Ilsan, Republic of Korea, 3: Department of Agriculture, Forestry and Bioresources, Seoul National University, Republic of Korea, 4: Research Institute of Agriculture and Life Sciences, Seoul National University, Republic of Korea)

With the development of remote sensing technology, one of the main challenges is establishing a system for monitoring hydrometeorological factors using satellites. The Korean government plans to launch the Compact Advanced Satellite 500-5 satellite for managing water resources in 2025, and it will be equipped with a C-band synthetic aperture radar with a resolution of 10 m and a swim width of 120 km. This project includes plans to provide soil moisture products, so stablishing a ground data network for reference is a very important task we face right now. However, in Korea, more than 70% of the country has mountainous areas, most of which are dense forests. Therefore, the spatial heterogeneity of soil moisture is very large, and it is very challenging to observe. For this reason, the accuracy and reliability of soil moisture data are low, so providing soil moisture data is very limited compared to other hydrometeorological factors. To overcome these limitations, we tried to adopt a CRNP that can install sensors safely and eco-friendly and secure high-quality spatial soil moisture data at an appropriate intermediate scale. We have evaluated the applicability of CRNP in Korea while constructing and operating two sites in Seolmacheon (SMC) and Hongcheon (HC). SMC and HC sites were installed in 2018 and 2022, respectively. We introduce two CRNP sites in Korea and discuss the calibration results and evaluation at each station. They showed good agreement with the average of capacitance sensors that are installed across the footprints. Also, they are effectively used to evaluate satellite-based soil moisture products. Therefore, we are planning to expand the CRNP sites gradually and establish a Korean cOsmic-ray Soil Moisture Observation System (KOSMOS).

Session 8

11:30 COSMOS-UK Operations – Network Standardisation to deliver over 10 years of near real time soil moisture and hydrometeorological data
Phil Vincent and COSMOS-UK Team
(UK Centre for Ecology & Hydrology, Wallingford, Oxfordshire, OX10 8BB, UK.)

COSMOS-UK is a network of 47 monitoring stations across the UK providing near real-time data on soil moisture using the Cosmic Ray Neutron Sensing technique. This network has been generating data for over 10 years providing valuable long-term data streams on soil hydrology and hydrometeorology to a range of applications. We will review the operational processes used to maintain the COSMOS-UK network since 2013 and how initial design and lessons learnt have continued to shape COSMOS-UK as an operational network. This review will include the full data processing chain and the flow of measurement data from sensor through to the end user application. Consideration will be given to maintaining data quality in an operational setting. This will include processes for maintaining optimal sensor operation, infrastructure development and site standardisation, identifying anomalous or erroneous data and the challenges in validating sensors and measurement data. Additionally future developments in data quality checking will be presented as well as the challenges of running a long-term, lean, operational network.

 

11:50 Advancing CRNS Processing: Towards Long-Term, Sustainable Research Tools
Daniel Power1, Steffen Zacharias1, Fredo Erxleben2, Thomas Förster2, Rafael Rosolem3,4 and Martin Schrön1
(1: Helmholtz Centre for Environmental Research GmbH, Leipzig, Germany, 2: Helmholtz-Zentrum Dresden-Rossendorg, Germany, 3: Department of Civil Engineering, University of Bristol, Bristol, UK, 4: Cabot Institute for the Environment, University of Bristol, Bristol, UK)

Cosmic-Ray Neutron Sensors (CRNS) are now well-established sensors, with applications ranging from long term monitoring, to roving surveys, to snow dynamics research. Despite having a strong research community, continually improving processing methods and sensor accuracy, the perceived complexity of the CRNS processing steps can act as a potential roadblock to its implementation across broader research infrastructures outside of the CRNS community. Existing software tools for CRNS processing, such as crspy and neptoon, have been crucial towards simplifying processing steps, however their inability to operate together, both designed with different frameworks, means future development will remain separate, doubling work on tools ultimately aiming to solve the same problem. We present here a revised tool set, combining the best aspects of each of the previous tools into a single interoperable framework. It has been written in Python, using current best practices in research software engineering, with a modular design and class-based structure, ensuring its long-term sustainability and extensibility. We include extensive documentation, for both users and developers, to support its use across the community. We present the first use case, a simple plug and play system, which is being piloted across the eLTER network, supporting the expansion of CRNS across Europe. We will additionally demonstrate how it can be used for CRNS research itself, allowing revised methods to be tested across hundreds of CRNS sites quickly.

Session 9

13:30 Recharge modelling using in a semi-arid tropical watershed
Deepti B Upadhyaya1, Rajsekhar Kandala1, Laurent Ruiz3,4, Jonathan Evans2, Ross Morrison2 and Sekhar Muddu1
(1: Department of Civil Engineering, Indian Institute of Science, Bangalore-560012, Karnataka, India, 2: UK Centre for Ecology & Hydrology, Wallingford, UK, 3: Indo-French Cell for Water Sciences, ICWaR, Indian Institute of Science, Bangalore, India, 4: G-EAU, INRAE, Univ Montpellier, AgroParisTech, Cirad, IRD, Institut Agro, Montpellier, France)

In the current study, a semi-arid agricultural watershed (Berambadi, south India) is investigated where groundwater level varies from year to year due to its exploitation for irrigation. The rainfall in this region shows high variability as well as the groundwater recharge. Our interest in the study is to model recharge from the ground surface using soil moisture (SM) from COSMOS as a proxy. The recharge estimation is highly sensitive to the scale, so our interest in this study is to check how the COSMOS data (500 m scale) and HydraProbe (point scale) influence the estimation of recharge by using the hydrological model Hydrus-1D. The data of HydraProbe and COSMOS from 2016 to 2022 were analysed and we will discuss the variability of the recharge values point scale and 500 m scale season-wise (South West monsoon -kharif and North East monsoon -rabi). The study period has varying annual rainfall of low (480 mm), normal (775 mm) and high (1500 mm). We compared the recharge from an irrigated site and a rainfed site estimated using point scale measurements (HydraProbe) and the COSMOS sensor situated in the same area. The two-point scale locations fall inside the area of influence of the COSMOS. The comparison of SM suggests that SM from COSMOS is averaging signals from irrigated and rainfed sites. The recharge values by using COSMOS in the low rainfall year act more like an irrigated point scale site than a rainfed site. However, during high rainfall years, the effect of both rainfed and irrigated sites was seen in the results using COSMOS.

 

13:50 Role of infiltration on land–atmosphere feedbacks in Central Europe: WRF-Hydro simulations evaluated with cosmic-ray neutron soil moisture measurements
Joël Arnault1,2, Benjamin Fersch2, Martin Schrön3, Heye Reemt Bogena4, Harrie-Jan Hendricks Franssen4 and Harald Kunstmann1,2
(1: University of Augsburg, Institute of Geography, Augsburg, Germany, 2: Karlsruhe Institute of Technology, Institute of Meteorology and Climate Research, Garmisch-Partenkirchen, Germany, 3: Helmholtz Centre for Environmental Research, Department of Monitoring and Exploration Technologies, Leipzig, Germany, 4: Forschungszentrum Jülich, Agrosphere Institute, Jülich, Germany)

The skill of regional climate models partly relies on their ability to represent land–atmosphere feedbacks in a realistic manner, through the coupling with a land surface model. However, these models often suffer from insufficient or erroneous information on soil hydraulic parameters. In this study, the land–atmosphere model WRF-Hydro driven with ERA5 reanalysis is employed to reproduce the regional climate over Central Europe with a horizontal resolution of 4 km, for the period 2017-2020. Simulated soil moisture is compared with data from cosmic-ray neutron sensors (CRNS) at three Terrestrial Environmental Observatories. Soil hydraulic parameters from continental and global digital soil datasets (i.e. SoilGrids and EU-SoilHydroGrids), together with Campbell and van Genuchten–Mualem retention curve equations, are used to assess the role of infiltration on modeled land–atmosphere feedbacks. The percolation parameter is calibrated to better capture observed discharge amounts in the observatories. WRF-Hydro with Campbell and SoilGrids gives the lowest mean temperature and mean precipitation differences compared to the E-OBS product from European Climate Assessment & Dataset, which is achieved by reducing soil moisture in the rootzone, increasing air temperature, and decreasing precipitation through a positive soil moisture–precipitation feedback process. WRF-Hydro with van Genuchten–Mualem and EU-SoilHydroGrids best reproduces CRNS soil moisture daily variations, despite enhanced positive biases that generate a larger proportion of convective precipitation favored over wet soils and spurious discharge peaks. The question remains open how an infiltration modeling option that better captures CRNS soil moisture dynamics can also lead to a clear improvement of the simulated weather conditions.

 

14:10 Future increases in soil moisture drought frequency at UK monitoring sites: merging the JULES land model with observations and convection-permitting UK Climate Projections
Magdalena Szczykulska, Chris Huntingford, Elizabeth Cooper and Jonathan G. Evans
(UK Centre for Ecology & Hydrology, Wallingford, Oxfordshire, OX10 8BB, UK)

Soil moisture is an important climatic variable playing a vital role in storing water for plant uptake. Continued greenhouse gas emissions and the resulting warming of the climate may lead to reduced agricultural water resources, which requires quantification. Here, we estimate future soil moisture levels under the high-emissions RCP8.5 scenario at 34 sites of the UK Cosmic-ray Soil Moisture Observing System (COSMOS-UK) network. We use the Joint UK Land Environment Simulator (JULES) model for modelling of soil moisture. As a first step, the soil parameters of the model are optimised against the COSMOS-UK field-scale soil moisture observations. The calibrated JULES model is then forced with 2.2 km convection-permitting UK Climate Projections (UKCP18) to yield soil moisture in three time periods: 1982-2000, 2022-2040 and 2062-2080. We analyse the data in the context of soil moisture droughts and the impact for individual months. We find that on average across all sites, there is an increase in future extreme soil moisture drought events above 90 days with respect to the historical period. In 2062-2080, the frequency of these events is expected to increase by a factor of between 1.8 and 2.8. We also find that months between May and November show an increased probability of high or more intense plant water stress in this far future period, with months between June and October being at especially high risk.

Session 10

15:00 Keynote: From Research to Operations – The Next Steps from a National Meteorological Service Point of View
Eoin Moran, Klara Finkele, Padraig Flattery, Sarah Gallagher, Haleh Karbala Ali, Sarah O’Reilly and Saji Varghese
(Met Éireann, Glasnevin, Dublin 9, Ireland)

The World Meteorological Organization (WMO) serves as the overarching body responsible for coordinating meteorological, climate and hydrological programs worldwide. In line with this mandate, the Global Climate Observation System (GCOS) has identified Essential Climate Variables (ECVs), including soil moisture, as crucial components for monitoring climate dynamics.

Within Europe, EUMETNET is a grouping of 33 European National Meteorological Services that provides a framework to organise co-operative programmes between its Members in the various fields of basic meteorological activities. EUMETNET spearheads specialized observation initiatives, such as the establishment of pollen observation networks. Leveraging existing infrastructure, these projects offer a promising avenue for advancing soil moisture observations from research projects to the development of a comprehensive, long-term monitoring network.

National Meteorological Services stand poised to play a pivotal role in this transition, facilitating the shift 'From Research to Operations.' Drawing on their extensive operational expertise and infrastructure, these services can collaborate with WMO's hydrological working groups to realize the vision of a robust and sustainable soil moisture monitoring framework for the future.

 

15:30 Project SoMMet - Soil Moisture Metrology
Miroslav Zboril, María de los Ángeles Millán Callado and the SoMMet Consortium
(Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig, Germany)

Soil moisture is one of the Essential Climate Variables as defined by the WMO Global Climate Observing System. Several soil moisture observation systems exist on multiple scales, however, poorly harmonized due to the lack of interlinks. There is a need to establish the chain of traceability, the metrological assessment of uncertainties and the harmonisation of soil moisture measurements within the hydrological cycle, on multiple scales ranging from point-scale sensors to satellite-based remote sensing techniques. In addition, there is an urgent need for real-time, continuous, high-quality, high-resolution and metrologically traceable and harmonised data on soil moisture. To address these needs, the project SoMMet (Soil Moisture Metrology) has been set up in the framework of the European Partnership on Metrology of EURAMET. The aim of the project is to develop sound metrological tools and establish a metrological foundation for soil moisture measurement methods on multiple scales, supporting the traceability and harmonisation initiatives.

In the presentation, an overview of the SoMMet objectives and research activities will be given. Specifically, the status of the characterisation and validation activities with Cosmic-Ray Neutron Sensing (CRNS) sensors in neutron metrology laboratories will be presented and discussed. The project 21GRD08 SoMMet has received funding from the European Partnership on Metrology, co-financed from the European Union’s Horizon Europe Research and Innovation Programme and by the Participating States.

 

15:50 European and Global Environmental Research Infrastructures – key partners towards a global CRNS network
Steffen Zacharias and Daniel Power
(UFZ Helmholtz Centre for Environmental Research, Dept. Monitoring and Exploration Technologies, Leipzig, Germany)

To address the challenges of global change, it is essential to have global cooperation, particularly from the scientific community. Earth System models at the continental or global scale are crucial for reanalysis, prediction, and projection in the face of changing climatic conditions and socio-ecological upheavals. The demand for environmental monitoring data has been increasing for decades and will continue to do so in the age of AI that has just begun. Global research infrastructures are crucial components of corresponding scientific strategies, and improving and strengthening the networking of existing RIs is a top priority, particularly from a political standpoint. Cross-network virtual and physical co-location demands community-accepted

measurement standards and data harmonization is needed. The CRNS-community has already taken steps to establish corresponding strategies but strong partners are needed to anchor such strategies internationally in the long-term. Several research collaborations have been established in the large RIs to better network the CRNS method internationally. We will present some of the most promising current developments in collaboration with European and global research infrastructures (RIs). We aim to encourage active engagement from the CRNS community in this strategic research environment.

 

16:10 Towards the establishment of a global COsmic-ray Soil Moisture Observing System
Rafael Rosolem and Global COSMOS team
(University of Bristol, UK)

Soil moisture is an important component of the water balance despite accounting for a small volume relative to other hydrological cycle components. With the continuing evolution of land surface and global hydrological models, characterizing soil moisture dynamics at sub-kilometer scales is becoming ever important. To help with that, the cosmic-ray neutron sensing is an established technology that provides estimates of root-zone soil moisture at relevant field scales. In simple terms, cosmic-ray neutron sensors can estimate root zone soil moisture through an indirect relationship between measured neutrons scattered from the soil and the amount of hydrogen atoms observed in the soil water.

Following its development in the late 2000s and the establishment of the first COsmic-ray Soil Moisture Observing System (COSMOS) network in the USA, a continuing adoption of this technology has been observed over the years, notably with the establishment of other national scale networks. As the cosmic-ray neutron sensing technology matures, so does our understanding on how to better isolate the soil moisture signal from other sources of hydrogen within the sensor footprint. However, despite recent improvements in our understanding, the evaluation of this technology at continental to global-scale datasets has been inexistent due to a lack of proper data harmonization. Here, we introduce the initial steps towards the harmonization of cosmic-ray neutron sensors worldwide. The harmonization is performed using the state-of-the-art and recent developed Cosmic-Ray Sensor PYthon data processing tool, applied to more than 200 stations. We highlight examples of applications using this global harmonized dataset in hydrology, agriculture, and environmental sciences; and present an open discussion about challenges and opportunities in potentially establishing a Global COSMOS network.