TY - JOUR AB - Ground-based measurements of neutrons from secondary cosmic rays are affected by environmental parameters, particularly hydrogen content in soil. To investigate the impact of these parameters, in particular snow cover, Geant4 Monte Carlo simulations were carried out. In a previous study the model used for the Geant4 Monte Carlo simulations was already validated by measurements performed with an extended-range Bonner sphere spectrometer (ERBSS) at Zugspitze, Germany, and at Jungfraujoch, Switzerland. In the present study a sensitivity analysis including different environmental parameters (i.e. slope of mountain, snow height, and soil moisture) and their influence on the flux of neutrons from secondary cosmic rays was performed with Geant4. The results are compared with ERBSS measurements performed in 2018 at the Environmental Research Station Schneefernerhaus located at the Zugspitze, Germany. It is shown that the slope of the Zugspitze mountain reduces the neutron flux from secondary cosmic rays between about 25 % and 50 % as compared to a horizontal surface, depending on neutron energy and snow cover. An increasing height of snow cover, simulated as snow water equivalent (SWE), reduces the total neutron flux exponentially down to a factor of about 2.5 as compared to soil without any snow cover, with a saturation for snow heights greater than 10 to 15 cm SWE, depending on neutron energy. Based on count rates measured with the individual spheres of the ERBSS, SWE values were deduced for the whole year 2018. Specifically, mean SWE values deduced for the winter months (January to March) are between 6.7 and 10.1 cm or more, while those for the summer months (July to September) are between 2.1 and 3.6 cm. Soil moisture of 5 % water mass fraction in limestone leads to a decrease of the total neutron flux by about 35 % compared to dry limestone. It is concluded that the measurement of neutrons from secondary cosmic radiation can be used to gain information on the height of snow cover and its seasonal changes, on soil moisture, and on local geometry such as mountain topography. Because the influence of such parameters on neutron flux from secondary cosmic rays depends on neutron energy, analysis of the whole neutron energy spectrum is beneficial. AU - Brall, T. AU - Mares, V. AU - Buetikofer, R.* AU - Rühm, W. C1 - 63315 C2 - 51276 CY - Bahnhofsallee 1e, Gottingen, 37081, Germany SP - 4769-4780 TI - Assessment of neutrons from secondary cosmic rays at mountain altitudes-Geant4 simulations of environmental parameters including soil moisture and snow cover. JO - Cryosphere VL - 15 IS - 10 PB - Copernicus Gesellschaft Mbh PY - 2021 SN - 1994-0416 ER - TY - JOUR AB -   Knowing the timing and the evolution of the snow melting process is very important, since it allows the prediction of: i) the snow melt onset; ii) the snow gliding and wet-snow avalanches; iii) the release of snow contaminants and iv) the runoff onset. The snowmelt can be monitored by jointly measuring snowpack parameters such as the snow water equivalent (SWE) or the amount of free liquid water content (LWC). However, continuous measurements of SWE and LWC are rare and difficult to be obtained. On the other hand, active microwave sensors such as the Synthetic Aperture Radar (SAR) mounted on board of satellites, are highly sensitive to LWC of the snowpack and can provide spatially distributed information with a high resolution. Moreover, with the introduction of Sentinel-1, SAR images are regularly acquired every 6 days over several places in the world. In this paper we analyze the correlation between the multi-temporal SAR backscattering and the snowmelt dynamics. We compared Sentinel-1 backscattering with snow properties derived from in situ observations and process-based snow modeling simulations for five alpine test sites in Italy, Germany and Switzerland considering two hydrological years. We found that the multi-temporal SAR measurements allow the identification of the three melting phases that characterize the melting process i.e., moistening, ripening and runoff. In detail, we found that the C-band SAR backscattering decreases as soon as the snow starts containing water, and that the backscattering increases as soon as SWE starts decreasing, which corresponds to the release of meltwater from the snowpack. We discuss the possible reasons of this increase, which are not directly correlated to the SWE decrease, but to the different snow conditions, which change the backscattering mechanisms. Finally, we show a spatially-distributed application of the identification of the runoff onset from SAR images for a mountain catchment, i.e., the Zugspitze catchment in Germany. Results allow to better understand the spatial and temporal evolution of melting dynamics in mountain regions. The presented investigation could have relevant applications for monitoring and predicting the snowmelt progress over large regions.   AU - Marin, C.* AU - Bertoldi, G.* AU - Premier, V.* AU - Callegari, M.* AU - Brida, C.* AU - Hürkamp, K. AU - Tschiersch, J. AU - Zebisch, M.* AU - Notarnicola, C.* C1 - 56863 C2 - 47271 SP - 935-956 TI - Use of Sentinel-1 radar observations to evaluate snowmelt dynamics in alpine regions. JO - Cryosphere VL - 14 PY - 2020 SN - 1994-0416 ER - TY - JOUR AB - The comparison of two shallow ice cores recovered in 1999 and 2000 from the same place on the Chimborazo summit glacier revealed the influence of the coincident Tungurahua volcanic eruption on their stable isotope and chemical records. The surface snow melting and water percolation induced from the ash deposition caused a preferential elution and re-localization of certain ionic species, while the stable isotope records were not affected. Additionally, the comparison of the ionic amount and some selected ion ratios preserved along the ice core column reports under which processes the chemical species are introduced in the snow pack, as snow flake condensation nuclei, by atmospheric scavenging or by dry deposition. This preliminary study is essential for the interpretation of the deep Chimborazo ice core, or for other sites where surrounding volcanic activity influences the glaciochemical records. AU - Ginot, P.* AU - Schotterer, U.* AU - Stichler, W. AU - Godoi, M.A.* AU - Francou, B.* AU - Schwikowski, M.* C1 - 6281 C2 - 28274 SP - 561-568 TI - Influence of the Tungurahua eruption on the ice core records of Chimborazo, Ecuador. JO - Cryosphere VL - 4 IS - 4 PB - Copernicus PY - 2010 SN - 1994-0416 ER -