Galactic Cosmic Rays (GCRs) are an intrinsic part of the heliospheric radiation environment, and an inevitable challenge to long-term space exploration. Here we show solar cycle induced GCR modulation at Mars in the period 2005-2020, along with GCR radial gradients, by utilising Mars Express and Rosetta engineering parameters compared to sunspot number time series. The engineering parameter used is called EDAC (Error Detection And Correction), a cumulative counter which is triggered by charged energetic particle causing memory errors in on-board computers. EDAC data provides a new way of gaining insight into the field of particle transport in the heliosphere, allowing us to circumvent the need for dedicated instrumentation as EDAC software is present on all spacecraft.

This data set can be used to capture variations of GCRs in both space and time, yielding the same qualitative information as ground-based neutron monitors. Our analysis of the Mars Express EDAC parameter reveals a strong solar cycle GCR modulation, yielding an anticorrelation coefficient of -0.5 at a time lag of ~5.5 months. By combining Mars Express with Rosetta data, we calculate a 5.3% increase in EDAC count rates per astronomical unit, attributed to a radial gradient in GCR fluxes in accordance with established literature.

The potential of engineering data for scientific purposes remains mostly unexplored. The results obtained from this work demonstrates, for the first time for heliophysics purposes, the usefulness of the EDAC engineering parameter, data mining and the utility of keeping missions operational for many years, providing complimentary data to nominal science instruments.

How to cite: Knusten, E. W., Witasse, O., Sanchez-Cano, B., Lester, M., Wimmer-Schweingruber, R., Denis, M., Godfrey, J., and Johnstone, A.: Galactic Cosmic Ray Modulation at Mars and beyond measured with EDACs on Mars Express and Rosetta, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11158, https://doi.org/10.5194/egusphere-egu21-11158, 2021.

Cosmic Rays, in particular the high charge and high energy (HZE) particles and eventual secondary low energy protons, are high Linear Energy Transfer (LET) radiation, i.e. they transfer a high amount of energy to the target per unit path length travelled in the target itself, leaving behind a dense track of ionization and atomic excitations. Understanding the radiation physics and the biology induced by the impact of high LET radiation is of importance for different fields of research, such as radiation therapy with charged particles, space radiation protection of astronauts and of human explorers on Mars and eventually also survival of any bacterial, plant cell on other planetary/small bodies. While data for low LET radiation  such as X-ray have been studied in the survivors of the atomic-bombs, medical patients and nuclear reactor workers, for high LET radiation there is no relevant collection of human data for risk estimates, and experiments with nuclei created at accelerators are necessary.

At present we still do not have an understanding of how the  radiation  interaction  with a  single nanometric  target (units of DNA), the so-called track  structure [1],  should  decide  the  fate  of  the  irradiated cell. Monte Carlo (MC) track structure codes essentially work only with the physics given by impact cross sections on the sole water, there is no real consideration of the electronic/chemical characteristics of the hosted biomolecule [2]. Limitations given by such an approach have been highlighted [3], but on the positive side a massive effort is being done to follow the different steps of radiation effects up to biological damage [4].

In this contribution we would like to highlight how a chain of models from different communities could be of help to study the radiation effects on biomolecules. In particular, we will present how ab-initio (parameter-free) approaches from the chemical-physics community can be used to derive in detail the energy loss of the impacting ions/secondary electrons on water and small biological units [5,6], either following in real time the ion or based on perturbative theories for low energy electrons, and how the derived quantity can be given  as input to Monte Carlo track structure codes, extending their capabilities to different relevant targets. Given the physical limitations and high costs of irradiation experiments, such calculations offer an efficient approach that can boost the understanding of radiation physics and consolidate existing MC track structure codes.

This work is initiated in the context of the EU H2020 project ESC2RAD, Grant 776410.

[1] H. Nikjoo, S. Uehara, W.E. Wilson, et al, International Journal of Radiation Biology 73, 355 (1998)

[2] H. Palmans, H Rabus, A L Belchior, et al, Br. J. Radiol. 88, 20140392 (2015)

[3] H. Rabus and H. Nettelback, Radiation Measurements 46, 1522 (2011)

[4] M. Karamitros, S. Luan, M.A. Bernal, et al,  Journal of Computational Physics 274,  841 (2014)

[5] B. Gu, B. Cunningham D. Munoz-Santiburcio, F. Da Pieve, E. Artacho and J. Kohanoff, J. Chem. Phys. 153, 034113 (2020)

[6] N. Koval, J. Kohanoff, E. Artacho et al, in preparation

How to cite: Da Pieve, F., Gu, B., Koval, N., Muñoz Santiburcio, D., Teunissen, J., Artacho, E., Cleri, F., and Kohanoff, J.: Towards parameter-free nanodosimetric quantities in the impact of highly ionizing radiation  , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16032, https://doi.org/10.5194/egusphere-egu21-16032, 2021.

Here we examine the cause-and-effect relations between galactic cosmic rays, electric field, aerosols and clouds over a region of Atlantic Ocean, during a Forbush Decrease (FD) event on 07/12/2015, using Convergent Cross Mapping (CCM) method. For this purpose, we used FD data from the Neuron Monitor Database (NMDB), Potential Gradient data (PG) from Global Coordination of Atmospheric Electricity Measurements (GLOCAEM) and remote sensing data from MODIS/Aqua, namely Aerosol Optical Depth at 550nm (AOD), Cloud Fraction (CF), Cloud Optical Thickness (COT), Cloud Top Pressure (CTP), Cirrus Reflectance (CR) and Cloud Effective Radius-Liquid (CERL). A cause-and-effect relation was found between FD and AOD, CERL, CF and PG, over the region. On the other hand, no causal effect was found between FD and COT, CTP and CR. This research is funded in the context of the project "Cosmic and electric effects on aerosols and clouds” (MIS: 5049552) under the call for proposals “Support for researchers with emphasis on young researchers - Cycle B” (EDULL 103). The project is co-financed by Greece and the European Union (European Social Fund - ESF) by the Operational Programme Human Resources Development, Education and Lifelong Learning 2014-2020.

How to cite: Stathopoulos, S., Misios, S., and Kourtidis, K.: Cause-and-effect relations between cosmic rays, electric field, aerosols and clouds, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-544, https://doi.org/10.5194/egusphere-egu21-544, 2021.

We present the first results of modelling of the short-living cosmogenic isotope ⁷Be production, deposition, and transport using the chemistry-climate model SOCOLv_3.0 aimed to study solar-terrestrial interactions and climate changes. We implemented an interactive deposition scheme,  based on gas tracers with and without nudging to the known meteorological fields. Production of ⁷Be was modelled using the 3D time-dependent Cosmic Ray induced Atmospheric Cascade (CRAC) model. The simulations were compared with the real concentrations (activity) and depositions measurements of ⁷Be in the air and water at Finnish stations. We have successfully reproduced and estimated the variability of the cosmogenic isotope ⁷Be produced by the galactic cosmic rays (GCR) on time scales longer than about a month, for the period of 2002–2008. The agreement between the modelled and measured data is very good (within 12%) providing a solid validation for the ability of the SOCOL CCM to reliably model production, transport, and deposition of cosmogenic isotopes, which is needed for precise studies of cosmic-ray variability in the past. 

How to cite: Golubenko, K., Rozanov, E., Kovaltsov, G., Leppänen, A.-P., and Usoskin, I.: Atmospheric production and transport of 7Be activity by cosmic rays: Modelling with the chemistry-climate model SOCOLv3.0 and comparison with direct measurements, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2287, https://doi.org/10.5194/egusphere-egu21-2287, 2021.

Secondary cosmic-ray neutrons may be effectively used as a proxy for environmental hydrogen content at the hectare scale. These neutrons are generated mostly in the upper layers of the atmosphere within particle showers induced by galactic cosmic rays and other secondary particles. Below 15 km altitude their intensity declines as primary cosmic rays become less abundant and the generated neutrons are attenuated by the atmospheric air. At the earth surface, the intensity of secondary cosmic-ray neutrons heavily depends on their attenuation within the atmosphere, i.e. the amount of air the neutrons and their precursors pass through. Local atmospheric pressure measurements present an effective means to account for the varying neutron attenuation potential of the atmospheric air column above the neutron sensor. Pressure variations possess the second largest impact on the above-ground epithermal neutron intensity. Thus, using epithermal neutrons to infer environmental hydrogen content requires precise knowledge on how to correct for atmospheric pressure changes.

We conducted several short-term field experiments in saturated environments and at different altitudes, i.e. different pressure states to observe the neutron intensity pressure relation over a wide range of pressure values. Moreover, we used long-term measurements above glaciers in order to monitor the local dependence of neutron intensities and pressure in a pressure range typically found in Cosmic-Ray Neutron Sensing. The results are presented along with a broad Monte Carlo simulation campaign using MCNP 6. In these simulations, primary cosmic rays are released above the earth atmosphere at different cut-off rigidities capturing the whole evolution of cosmic-ray neutrons from generation to attenuation and annihilation. The simulated and experimentally derived pressure relation of cosmic-ray neutrons is compared to those of similar studies and assessed in the light of an appropriate atmospheric pressure correction for Cosmic-Ray Neutron Sensing.

How to cite: Weimar, J., Schattan, P., Schrön, M., Köhli, M., Gugerli, R., Stevanato, L., Achleitner, S., and Schmidt, U.: A reevaluation of the atmospheric pressure dependence of secondary cosmic-ray neutrons in the context of Cosmic-Ray Neutron Sensing, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10602, https://doi.org/10.5194/egusphere-egu21-10602, 2021.

The novel method of Cosmic-ray neutron sensing (CRNS) allows non-invasive soil moisture measurements at a hectometer scaled footprint. Up to now, the conversion of soil moisture to a detectable neutron count rate relies mainly on the equation presented by Desilets et al. (2010). While in general a hyperbolic expression can be derived from theoretical considerations, their empiric parameterisation needs to be revised for two reasons. Firstly, a rigorous mathematical treatment reveals that the values of the four parameters are ambiguous because their values are not independent. We find a 3-parameter equation with unambiguous values of the parameters which is equivalent in any other respect to the 4-parameter equation. Secondly, high-resolution Monte-Carlo simulations revealed a systematic deviation of the count rate to soil moisture relation especially for extremely dry conditions as well as very humid conditions. That is a hint, that a smaller contribution to the intensity was forgotten or not adequately treated by the conventional approach. Investigating the above-ground neutron flux by a broadly based Monte-Carlo simulation campaign revealed a more detailed understanding of different contributions to this signal, especially targeting air humidity corrections. The packages MCNP and URANOS were used to derive a function able to describe the respective dependencies including the effect of different hydrogen pools and the detector-specific response function. The new relationship has been tested at three exemplary measurement sites and its remarkable performance allows for a promising prospect of more comprehensive data quality in the future.

How to cite: Köhli, M., Weimar, J., Fersch, B., Baatz, R., Schrön, M., and Schmidt, U.: Moisture and humidity dependence of the above-ground cosmic-ray neutron intensity revised, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9215, https://doi.org/10.5194/egusphere-egu21-9215, 2021.

Cosmic-Ray Neutron Sensing (CRNS) delivers an integral value of soil moisture over a radial footprint of 150 to 240 m and a penetration depth of 15 to 83 cm. The support volume, especially in the vertical extent, decreases with increasing soil moisture. As the sensor is most sensitive to upper soil layers and the signal contribution decreases with increasing depth, the vertical distribution of moisture influences the signal received by the neutron detector. Additional soil moisture measurements are required to estimate the penetration depth of the CRNS measurement. These may be provided by profile measurements of a soil moisture monitoring network equipped with buried electromagnetic sensors. Different horizontal and vertical weighting schemes exist to compare the integrated CRNS value to an integrated (weighted) average value from a sensor network by adjusting reference measurements to the spatial sensitivity of the sensor. The vertical weighting was developed based on hydrodynamic modelling of a soil column and a neutron transport model (MCNPx). Since then the development of the Ultra Rapid Adaptable Neutron-Only Simulation (URANOS) opened up the possibilities for more complex neutron simulations to understand and interpret the CRNS signal. Simulations confirmed the large influence of soil moisture on the penetration depth of the sensor for homogeneous vertical soil moisture distributions, rarely occurring in natural environments. While in recent years the influence of horizontal heterogeneities on the signal generation was the focus of several studies, the influence of vertical gradients achieved less attention.

Against this background, we evaluate data from a field site in southern Germany with clayey soils and influence of shallow groundwater, where a CRNS is operated in parallel to a soil moisture monitoring network. We observe a good match between the time series of CRNS derived soil moisture and the weighted soil moisture from the sensor network during infiltration events. Several times during summer, however, topsoil dries and a strong vertical gradient develops (0.20 m³ m^-³ in 5 cm to 0.50 m³ m^-³ in 20 cm depth). During these periods the weighted sensor network underestimates CRNS derived soil moisture by up to 0.25 m³ m^-³. We hypothesize, that the estimation of the penetration depth does not hold for these extreme soil moisture gradients and that neutrons penetrate deeper into the soil and probe the wetter layers. The combination of observed neutron intensities as well as dedicated neutron transport simulations using the URANOS and MNCP6 model code will help to understand the site-specific signal behavior, explain differences observed in the data and lastly, gain information on the behavior of neutron intensities under vertically varying soil moisture contents.

How to cite: Scheiffele, L. M., Weimar, J., Rasche, D., Fersch, B., and Oswald, S. E.: Penetration depth of Cosmic-ray neutron sensing for soil moisture under extreme vertical soil moisture gradients in measurements and modelling, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15240, https://doi.org/10.5194/egusphere-egu21-15240, 2021.

Cosmic-Ray Neutron Sensing (CRNS) has constantly advanced during the last decade as a modern technique for non-invasive soil moisture estimation at the field scale. Latest studies led to an improved understanding of the CRNS integration volume, weighting functions for reference soil moisture measurements and correction procedures of raw neutron counts.

It is common knowledge that soil moisture is highly variable in space. Nevertheless, the CRNS processing techniques currently assume that there is little structure to this variability within the 10 ha measurement footprint, i.e. no distinct difference in average moisture content between near and far field. In particular, with a single CRNS probe and the current knowledge it is not possible to separate different soil moisture conditions within the footprint.

Against this background, we investigated the effect of soil moisture patterns on the size of the measurement footprint and on the response of thermal and epithermal neutron intensities at a CRNS observation site in north-eastern Germany. The site exhibits pronounced differences in soil water content (and dynamics) in the near (0-60 m) and far field (> 60 m) of the neutron detector as the near field is dominated by mineral and the far field by organic peatland soils.

Neutron transport simulations with URANOS revealed that thermal neutrons have a smaller measurement footprint compared to epithermal neutrons. We show that thermal neutrons mainly originated from the mineral soils in the near field, while the larger epithermal footprint area also includes the peatland soils. However, the simulated thermal neutrons still seem to be influenced by peatland soil water variations.

With the support of the computer simulations, we were able to better interpret and identify patterns in the observed neutron count rates that represent different features of the heterogeneous field site. The study presents a new application for thermal detectors in concert with the standard epithermal detectors, and revealed opportunities for improving the calibration against soil moisture reference measurements in the near field. We illustrate the potential of CRNS for estimating soil moisture time series at heterogeneous study sites and for disentangling different soil moisture conditions within the measurement footprint.

How to cite: Rasche, D., Köhli, M., Schrön, M., Blume, T., and Güntner, A.: Towards disentangling heterogeneous soil moisture patterns in Cosmic-Ray Neutron Sensor footprints, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12880, https://doi.org/10.5194/egusphere-egu21-12880, 2021.

Climate change and its impacts at local scales, such as the more frequent occurrence of extreme weather events like droughts or floods, pose an increasing problem for agriculture. Our aim is to support farmers with soil condition and weather forecasting products that provide the basis for optimal adaptation to short-term weather variability and extremes as well as to long-term, regional climate change.

For this purpose, a prototypical monitoring and real-time forecasting system was established. The monitoring networks consist of a novel cosmic ray neutron sensor (Styx Neutronica), soil moisture and temperature sensors in four depths between 5 and 60 cm (SoilNet) and an all-in-one weather station (ATMOS-41, METER Environment) to measure the atmospheric conditions including air temperature, humidity, pressure, solar irradiance, wind speed and precipitation at 2 meter height above ground. The observation data are transmitted in real time to a cloud server via the cellular solution NBIoT (Narrow Band Internet of Things). After data post-processing the meteorological and hydrological parameters measured on site are directly assimilated into the fully coupled multi-physical numerical model system TSMP (Terrestrial Systems Modeling Platform, www.terrsysmp.org) at Forschungszentrum Jülich. ParFlow hydrologic model (www.parflow.org) is used in combination with the Community Land Model (CLM) to predict hourly, high-resolution (near plot level) information on soil moisture or other soil and meteorological parameters for the next 10 days. A special feature here is the prediction on the temporal development of plant-available water between 0-60cm depth for the sites of our monitoring network partners.

Observation data as well as the forecasting products are published in near real time on the digital product platform www.adapter-projekt.de. Users thus have direct access to relevant information that support them in planning agricultural management, e.g. irrigation and fertilization requirements, trafficability or workability.

How to cite: Ney, P., Belleflamme, A., Iakunin, M., Wagner, N., Bathiany, S., Pfeifer, S., El Zohbi, J., Rechid, D., Görgen, K., and Bogena, H.: Establishment of a network of soil moisture and cosmic ray neutron sensors for data assimilation and optimization of high-resolution, real-time predictions, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15539, https://doi.org/10.5194/egusphere-egu21-15539, 2021.