bluuebunny/crossref_metadata_2025 huggingface dataset:
Paleomagnetic research of the Upper Miocene sections of Taman Peninsula (Eastern Paratethys)
Authors: Salnaia Natalia , Rostovtseva Yuliana , Pilipenko Olga
Published: March 2022

Magnetostratigraphic studies currently play an important role in the dating of the Miocene sections of the Kerch-Taman region (Eastern Paratethys). The major goal of our work was the paleomagnetic and rock magnetic studies of the transient Sarmatian-Meotian deposits in order to estimate the relative age (pre- or postfolding) of the natural remanent magnetization (NRM) using field tests. In order to solve this problem, during fieldwork in 2020-2021 the 280 hand-blocks at 0.1-2 m step were sampled from the key sections of the Sarmatian-Meotian transition - Popov Kamen, Panagia, Taman, and Tuzla (Taman Peninsula, Southern Russia). These sections located on different limbs of folds from one folded system. Thanks to rock magnetic studies, at least two magnetic minerals are determined - magnetic iron sulfide (presumably, greigite) and magnetite. NRM directions of two polarities, mostly isolated in the low-temperature interval and associated, apparently, with greigite, are determined. According to the results of paleomagnetic studies, a correlation between the bedding elements and NRM directions in the stratigraphic coordinate system is traceable. This, as well as the thermomagnetic results, show that the fold test for Popov Kamen and Panagia sections are negative, testify in favor of remagnetization, at least in part, of these sections. Our results suggest the impossibility of using the magnetostratigraphic method for dating the studied part of the sections Popov Kamen, Panagia, Taman, and Tuzla.

This work was supported by the Russian Science Foundation grant No. 19-77-10075.
Origin of the solar wind observed by PSP 
Authors: Magdalenic Jasmina , Valliappan Senthamizh Pavai , Rodriguez Luciano
Published: March 2022

The recently available novel Parker Solar Probe (PSP) observations allow mapping of the solar wind characteristics in the low solar corona, at only a few tens of solar radii, and study the characteristics of the solar wind and its transients close to the Sun. The first few perihelion passes of the PSP revealed the highly variable structure of the solar wind. These observations provided the unique possibility to study the solar wind originating from small coronal holes. Such studies were previously not possible as the majority of the in situ observations were taken at distances of about 1 AU, and the association of the solar wind originating from the small coronal holes and its sources on the Sun was extremely unreliable. We employ a magnetic connectivity tool (developed by ESA’s MADAWG group) to associate the solar wind parcels observed by the PSP with their source regions on the Sun.  Our study encompasses the first eight PSP perihelion passes, using a time window of about three weeks around each perihelion. The first results indicate that we can well distinguish and identify the solar wind observed by the PSP originating not only from the big, but also from the small coronal holes.
Validation of DGFI-TUM’s new ionosphere model: case studies for year 2018
Authors: Krypiak-Gregorczyk Anna , Milanowska Beata , Schmidt Michael , Goss Andreas , Erdogan Eren , Jarmołowski Wojciech , Wielgosz Paweł
Published: March 2022

In the last decades, advances in satellite technologies, data analysis techniques, and models, and a growing number of analysis centers allow modeling the ionospheric electron content with unprecedented accuracy. International GNSS Service (IGS) Ionosphere Associated Analysis Centers (IAAC) continuously provide global ionospheric maps (GIMs) based on processing GNSS data from the ground IGS network. It is a great advantage that these GIMs are often based on very different modeling techniques and thus, are also characterized by different accuracy levels. Due to the dynamic nature of the ionosphere, there is a permanent need to improve the modeling techniques of ionospheric key parameters such as the vertical total electron content (vTEC).

In this presentation, we evaluate a new ionosphere model from DGFI-TUM denoted OTHG, which is a candidate for a new IGS IAAC product. The OTHG model is based on tensor products of trigonometric B-spline functions in longitude and polynomial B-spline functions in latitude for a global representation (Goss et al. 2019). Here, we complement our earlier investigations of the seven analysis center models (Wielgosz et al. 2021) with new results for the OTHG GIMs. For these investigations, we use our own validation methodology presented in Krypiak-Gregorczyk et al. (2017), which is based on GIM-derived slant TEC (sTEC) comparison with carrier phase geometry-free combination of GNSS signals. In the presented study, we use one year of GNSS data collected by 25 globally distributed stations. The overall yearly RMS value is calculated for each product based on all 365 days of continuous observations from all stations. The results show that the overall RMS of the tested GIMs ranges from 0.93 TECU to 1.29 TECU. The OTHG GIMs performed as one of the best. In addition, GIM vTEC comparisons to Jason-2 and Jason - 3 altimetry data are studied. In these analyses, the OTHG GIMs also showed a good performance. Therefore, it can be concluded that  DGFI-TUM is a valuable ionospheric product for the research community.

 

Goss A., Schmidt M., Erdogan E., Görres B., Seitz F. (2019) High-resolution vertical total electron content maps based on multi-scale B-spline representations. Annales Geophysicae, 37(4), 10.5194/angeo-37-699-2019

Krypiak-Gregorczyk A., Wielgosz P., Borkowski A. (2017) Ionosphere Model for European Region Based on Multi-GNSS Data and TPS Interpolation, Remote Sensing, 9(12), 1221,  DOI:10.3390/rs9121221

Wielgosz P., Milanowska B., Krypiak-Gregorczyk A., Jarmołowski W. (2021) Validation of GNSS‑derived global ionosphere maps for different solar activity levels: case studies for years 2014 and 2018. GPS Solutions 25, 103. https://doi.org/10.1007/s10291-021-01142-x
Retrieval of Humidity Profile Using Refractive Index of UHF Wind Profiler Radar 
Authors: Kim Min Seong , Kwon Byung Hyuk , Kim SangJin , Lee KyungHun , Kim YuJin
Published: March 2022

In the atmospheric boundary layer (ABL), the humidity profile was retrieved by combining the data of the radiometer and the wind profiler, and was compared with that of the GPS radiosonde. The variation of the amount of precipitable water (PW) was analyzed in sea breeze, typhoon, and precipitation cases. High-frequency electromagnetic waves emitted from the wind profiler are affected by atmospheric thermodynamic factors (temperature, humidity, and atmospheric pressure). An algorithm was developed to determine the optimal vertical gradient of refractivity (M) which plays important role in the vertical variation of humidity. M was corrected in consideration of the boundary layer height estimated by the wind profiler and the humidity characteristics in the mixed layer. The root mean square error (RMSE) of the retrieved specific humidity was 1.72 g/kg, which was twice as low as the RMSE 3.42 g/kg of radiometer specific humidity. The variation of PW is essential for understanding the structure of the ABL. As the sea breeze blows, the PW increased in the lower layer. As the typhoon approaches the Korean Peninsula, the lower level PW increased rapidly. The PW before and after precipitation showed clear increase and decrease, respectively except for summer season when there is enough water vapor
A Numerical Study of Wormhole Formation and Growth in Homogeneous and Heterogeneous Carbonate Rocks
Authors: Furui Kenji , Yoshioka Keita
Published: March 2022

Wormholes are an effective fluid conduit that dominate the flow path in karst aquifers and are artificially induced in geo-energy applications through acid injection. As acidic fluids infiltrate geologic formations, they react with the minerals in the formation. The reaction localizes and forms a dendritic dissolution pattern under certain conditions, known as the reaction infiltration instability. This instability is instigated by material heterogeneities in most computational models. However, studies have demonstrated that injection of water into a homogeneous plaster can initiate and grow wormholes. In this study, we show that material heterogeneities suppress the wormhole growth in carbonate rocks compared with a homogeneous counterpart. Wormholes were numerically simulated through injection of a strong acid (hydrochloric acid) under both homogeneous and heterogeneous permeability fields using a phase-field approach. The phase-field variable represents calcite dissolution in a diffused manner and is coupled with a reactive flow model assuming convective and diffusive acid transport in the liquid phase and significantly high surface reaction rate, which emulate typical high-rate matrix acidizing treatments in carbonate reservoirs. Heterogeneous permeability fields localize the flow in high-permeability domains and enhance the splitting and branching of wormholes. The length of the dominant wormholes can be suppressed as an increasing amount of acid infiltrates into the branched wormholes. Our findings indicate that material heterogeneities should not be treated as a trigger for wormholes in the numerical simulation but as one of the parameters to control their nucleation and growth. 
Characteristics, Generation, and Propagation of Nonlinear Internal Waves Observed in the Northern East China Sea
Authors: Lee Seung-Woo , Nam SungHyun
Published: March 2022

Oceanic nonlinear internal waves (NLIWs) play an important role in regional circulation, marine biogeochemistry, energetics, vertical mixing, underwater acoustics, marine engineering, and submarine navigation, most commonly generated by the interaction between barotropic tides and bathymetry. However, our understanding of their characteristics, generation, and propagation is still far from complete in many water bodies. Here, we present the characteristics of NLIWs observed from moored and underway observation in the northern East China Sea during May 15-28, 2015 and discuss their generation and propagation. The NLIWs observed during the experiment were characterized by an amplitude ranging from 4 to 16 m, width ranging from 380 to 600 m, and propagated southwestward at a speed of 0.64–0.72 m s−1. Groups of NLIWs were predominantly observed during, or a couple of days after, the period of spring tides, with a time interval 24–96 min shorter than the canonical semidiurnal period (12.42 h; M2); this is in contrast to those found in many other regions that have a phase-locking to the barotropic semidiurnal tides. The remote generation and propagation of the NLIWs from potential generation sites into the study area under time-varying stratification support the fact that the time interval departed from the semidiurnal period. Our results have substantial implications for turbulent mixing and ocean circulation in regions where the shelf is broad and shallow. The NLIWs generated from multiple sources propagate in multiple directions with propagating speeds varying over days depending on stratification. 
Physics Based Seismicity Rate Computation For Northeast Himalaya, India
Authors: Pandey Auchitya Kumar , Chingtham Prasanta , Roy Paresh Nath Singha
Published: March 2022

The computation of probable occurrence of future large earthquakes is the prime objective of the present study in the Northeast Himalaya India. For this purpose, the physics based rate-and-state friction law is adopted for forecasting the seismicity rate changes for MW ≥ 5.0 during the period 2016-2020. The coulomb stress changes (ΔCFF) is consider as a principle component which associated with the earthquake ruptured from the receiver’s fault. The reason behind considering the coulomb stress changes lies on the fact that the seismicity rate increases where the stress increase and decrease where the stress decreases. Here, it has been observed that high ΔCFF values are found widespread along the Main Central Thrust. Moreover, highest b-value is found to be in and around the Sikkim Himalaya. However, the highest background seismicity rate is also obtained in the vicinity of Sikkim and Bhutan with values ranging from 0 to 3.6. Finally, we have considered the consecutive fault parameter (Aσ = 0.05 MPa) for computing the forecast model with variable ΔCFF and heterogeneous b-value. The different value of the constitutive parameter (Aσ = 0.01, 0.02, 0.09, and 0.30 MPa) is adopted to understand the contribution of this parameter in a sudden change of seismicity rate due to stress perturbations. Also, various friction coefficient values (μ' = 0.2, 0.5, 0.6 and 0.8) are considered to find out the variation of seismicity rate changes. Then, CSEP model have been explored to check the consistency between the observed earthquakes and forecasted seismicity rates. The result from the CSEP model approves that the observed earthquakes matches well with the forecasted seismicity rates, thereby showing the consistency and efficiency of our forecast model.
Estimating the variation in runoff due to landcover changes using the SWAT model
Authors: Sarkar Basu Arunima , Pilla Francesco
Published: March 2022

Land use and land cover changes are majorly associated with the anthropogenic causes as well as human growth and urban expansion. The rapid increase in urban development is interlinked to fragmentation of landcover changes leading to a rise in flood events. The growth rate of urbanization has been quite significant in Ireland over the past 30 years. Ireland’s annual growth rate of urbanization was found to be 3.1% between 1990 to 2012. Several studies have further documented that Ireland experienced an overall higher degree of land conversion relative to other European countries, concluding that the urban land expansion in Ireland has been among the highest in Europe. The majority of the physically-based hydrological models that are used to simulate the discharge dynamics from river basin outlets require land cover information. One of the major limitations of those models is that they, in general, assume that the land cover information remains the same over time. However, changes in land cover are evolving over time, which needs to be considered while simulating runoff at a river basin. In situations where the hydrological model is used to simulate runoff for a short period of time, ranging from a few months to a few years, a static land cover information might be sufficient, however, when runoff simulations are required for longer periods of time (more than a decade), it is important to consider the changes in land cover over such a period. This study investigates how changes in land cover impact hydrological runoff simulations using a rainfall-runoff model called soil water assessment tool (SWAT). The study area considered is the Dodder River basin located in southern Dublin, Ireland. Runoff at the basin outlet was simulated using SWAT for 1993–2019 using five landcover maps obtained for 1990, 2000, 2006, 2012 and 2018. The hypothesis specifically points to the consideration of dynamic and time-varying landcover data during the development of hydrological modelling for runoff simulation. Furthermore, two composite quantile functions were generated by using a kappa distribution for monthly mean runoff and GEV distribution for monthly maximum runoff, based on model simulations obtained using different landcover data corresponding to different time-period.
Oblique continental rifting. Insights from 3-D forward geodynamic modelling coupled with surface processes and application to the Equatorial passive margins formation.
Authors: Huismans Ritske S. , Theunissen Thomas , Rouby Delphine , Wolf Sebastian G. , May Dave
Published: March 2022

Plate divergence (continental rifting) is often oblique to the rift axis or plate boundary, comprising many active rifts and mature rifted margins on Earth. Recent findings from field-based studies, plate reconstructions and numerical and analog models suggest that rift obliquity plays a critical role in rift evolution and imparts fundamental controls on the eventual architecture of mid-ocean ridges and mature rifted margins. These studies show the importance of vertical strike-slip and transform structures in the oblique extension process but also reveal that the initiation of syn-rift vertical strike-slip motion over long distances requires inherited weaknesses. As a typical example the Southern part of the Equatorial passive rifted conjugate margins exhibit segments with different tectonics and subsidence histories alternating with transform segment with different lengths and orientation. We aim in this study 1) to evaluate the role of the inheritance (obliquity, geometry of weaknesses) in controlling the pattern of faulting (type of fault, direction of propagation, and linkage), and 2) to evaluate the feedback between tectonics and surface processes in this context to understand consequences on landscape evolution. For this purpose we use most recent advances in 3-D forward geodynamic modeling coupled with surface processes. Preliminary results confirm the importance of inheritance in shaping the continental rift by controlling fault propagation leading to oblique segments with variable tectonics and subsidence history and show some unexpected feedbacks between tectonics and surface processes. These results compare well to the Equatorial system and provide important insight on the causes that might explain timing and amplitude of vertical motions and related sediment flux.
The ecology of wild microorganisms in a changing climate
Authors: Hungate Bruce
Published: March 2022

Climate warming can alter microbial activity, potentially altering the composition of the atmosphere and feeding back to climate, as well as health of soils that support production of food and fiber. The vast variation in microbial metabolism, physiology, and traits means that different microorganisms are likely to respond differently to the same forcings. For example, some microorganisms appear to thrive with warming, some are unresponsive, and others decline. Such differences in responses likely result in different contributions by microorganisms to terrestrial feedbacks to climate change, like carbon storage and loss from soils, as well as the release and exchange of the potent greenhouse gases nitrous oxide and methane. Characterizing the magnitude and significance of differential biological responses and feedbacks to environmental forcing is a major focus of ecosystem science and functional ecology. Doing so for microorganisms is challenging, but vitally important given the size and uncertainty of microbial feedbacks to the changing climate. Addressing these issues requires quantitative measurements of microbial responses to warming, responses that can be translated into the material flows in nature that constitute the feedbacks of interest. Further, we need to aim toward quantifying microbial responses under field conditions, under conditions where we can simultaneously characterize the magnitude of the feedback and thus have common context for connecting the two. Examples of efforts to make these connections will be presented, from warming experiments across biomes. Quantitative field-based microbial ecology can push the field by revealing the biology and evolution of the key drivers of important feedbacks to the changing climate and atmosphere, and may help identify organisms that are especially effective in promoting the ecosystem processes that protect the climate.
Hydrography, circulation and warm inflow toward the central Getz Ice Shelf: two years of mooring observations
Authors: Dundas Vår , Darelius Elin , Daae Kjersti , Steiger Nadine , Nakayama Yoshihiro , Kim Tae-Wan
Published: March 2022

As the melt rates of Getz Ice Shelf (GIS) increase, its grounding line is retreating, possibly destabilizing GIS. Detailed oceanographic observations from all the GIS frontal regions are needed to describe its drivers of basal melt and obtain an accurate projection of its melt rates. We present the first mooring observations from the bathymetrically sheltered trough between Siple and Carney Islands - one of the remaining GIS fronts to be described in detail. Although the ocean is colder in this central trough compared to what is observed in adjacent troughs, temperatures more than 1° above freezing are present throughout the mooring period, with a positive mean heat transport directed towards the ice shelf. Output from a high-resolution regional model indicates that heat is advected to the trough from both the eastern Amundsen Sea and from the continental shelf break in the north. The variability in heat content and heat transport are both affected by ocean surface stress, but while westward stress drives increased heat transport towards the ice shelf, eastward stress drives enhanced heat content. These relationships are most prominent in winter. Anomalously low summertime sea ice concentration and weak winds during the mooring period appear to suppress the effect of a strong positive anomaly in cumulative Ekman pumping, causing relatively low heat content during the mooring period compared to long-term estimates from the regional model.
Assessing uncertainty in groundwater flow directions by an iterative Ensemble Smoother technique
Authors: Formentin Giovanni , Marazuela Miguel Angel , Erlmeier Klaus , Tepe Nathalie , Hofmann Thilo
Published: March 2022

A sub-alpine catchment hosts a drinking water plant that collects groundwater through a series of drains. The catchment is crossed by a river that recharges the aquifer with potentially polluted water. The waterworks managers need a management strategy to maximize groundwater collection and minimize the probability to extract river water. This request was addressed by means of a groundwater model that simulates the mixing of river water and groundwater under a stochastic framework.

Samples of river water show the presence of Gadolinium, a rare earth element used as a contrast agent (GBCA) for magnetic resonance imaging. This element is also recurrently found in samples taken from some monitoring wells, and previous studies have determined its suitability as a tracer of solute dispersion. We used it as an indicator of partitioning between river water and original groundwater.

We built a simple, fast-running numerical groundwater model with the FEM code Feflow (DHI). We coupled it with PESTPP-IES, an optimization tool that implements the ensemble-smoother form of the Gauss-Levenberg-Marquardt algorithm. Through it, an ensemble of "realistic" parameter fields was generated, all of which support a good fit between model outputs and the calibration dataset. The latter included mixing ratios (calculated by measured Gadolinium concentrations) and groundwater levels. To simulate Gadolinium spread in groundwater, we used particle tracking instead of building an advective-dispersive transport model, because the latter is costlier to build and slower to run, therefore it does not allow the high number of runs required by PESTPP-IES. Although dispersion is not explicitly represented, its role is surrogated by uncertainty in hydraulic conductivity.

With this study, we built the engine of a decision support system that will optimize waterworks management. We also demonstrated that a lean, purpose-driven model is adequate in simulating solute transport in complex hydrogeological systems. Gadolinium concentrations were instrumental in identifying the partitioning between river water and groundwater.
Investigating the influence of local insolation on near-surface snow grain properties to constrain the mechanisms of pore close-off and associated elemental fractionation in polar firn
Authors: Harris Stuart Romilly , Landais Amaëlle , Martinerie Patricia , Dumont Marie , Fructus Mathieu , Orsi Anaïs , Libois Quentin , Arnaud Laurent , Stevens C. Max , Grisart Antoine , Prié Frédéric
Published: March 2022

Processes controlling pore closure in deep polar firn are broadly understood, yet defining the physical mechanisms remains ambiguous. Firn densification models predict pore close-off depths which are subsequently used in firn air models to predict the gas-ages of entrapped air bubbles. However, current firn models require observational tuning which causes variable model performance for sites with different characteristics. Furthermore, layering in the deep firn, which is not simulated in many firn densification models, is expected to cause a large distribution of pore lock-in depths. Observations from numerous firn cores have identified neighbouring layers with different physical properties, such as density, grain size and impurities, which experience pore-closure at different depths. These properties are strongly influenced by 1) snow metamorphism due to temperature gradients within the snowpack, and 2) accumulation rate. The relative influence of each of these properties on pore closure remains in question.

Based on current understanding, we propose to quantify the changes in density and snow microstructural properties near the surface as a result of the interplay between accumulation rate and insolation using the Crocus snowpack model. To support the modelling effort, we have compiled δO2/N2 records - a proxy for local summer solstice insolation - from several polar ice cores. The relationship between insolation and δO2/N2 is understood to be linked to near-surface snow metamorphism, which largely determines the properties of deep-firn layers, and thus, the pore-closure process. By first identifying how insolation and accumulation rate influence the near-surface snow properties, we aim to implement this effect into firn models to develop our understanding of the physical mechanisms controlling pore-closure and the associated elemental fractionation.
Where is Arctic coastal infrastructure at risk?
Authors: Bartsch Annett , Widhalm Barbara , Pointner Georg , von Baeckmann Clemens , Nitze Ingmar , Grosse Guido , Lantuit Hugues , Irrgang Anna , Boike Julia , Vieira Goncalo
Published: March 2022

Infrastructure and anthropogenic impacts are expanding across the Arctic. A consistent record of human impact is required in order to quantify the changes and to assess climate change impacts on the communities.
We derived a first panarctic satellite-based record of expanding infrastructure and anthropogenic impacts along all permafrost affected coasts (100 km buffer) within the H2020 project Nunataryuk based on Sentinel-1/2 satellite imagery. C-band synthetic aperture radar and multi-spectral information is combined through a machine learning framework. Depending on region, we identified up to 50% more information (human presence) than in OpenStreetMap. The combination with satellite records on vegetation change (specifically NDVI from Landsat since 2000) allowed quantification of recent expansion of infrastructure. Most of the expanded human presence occurred in Russia related predominantly to oil/gas industry.

The majority of areas with human presence in this coastal zone will be subject to thaw by mid-21st century based on ground temperature trends derived from the ESA CCI+ Permafrost time series (1997-2019). Of specific concern in this context are also settlements located directly at permafrost affected coasts. An efficient erosion rate monitoring scheme needs to be developed and combined with settlement records and permafrost information in order to assess the risk for local communities and infrastructure. Relevant progress in the framework of the ESA EO4PAC project will be discussed.
Modelling water isotopes using a global non-hydrostatic model with explicit convection scheme
Authors: Tanoue Masahiro , Yashiro Hisashi , Takano Yuki , Yoshimura Kei , Kodama Chihiro , Satoh Masaki
Published: March 2022

The stable water isotopes (SWIs) (δ18O and δD) are used as an indicator of the intensity of the atmospheric hydrological cycle due to their large variability in time and space. SWIs are used for investigating the model’s bias and uncertainty. In this study, we developed a new global storm-resolving model equipped with SWIs (NICAM-WISO). We applied the new model to conduct three current climate simulations using a single-moment cloud microphysics scheme, without any convection parameterization scheme: CTRL, LRES, and HRES. These simulations used the same physical process but at a different horizontal resolution (LRES, 224 km; CTRL, 56 km; HRES, 14 km). We conducted the simulations on the supercomputer Fugaku. CTRL reproduced the seasonal means of the atmospheric hydrological cycle, as well as precipitation isotopic ratios. However, all simulation results have three types of biases. First, in tropical ocean regions, the model had a negative bias in precipitation isotopic ratios; this was caused by a negative bias in vapor isotopic ratios for the middle troposphere, which resulted from excess condensation biases during upward transportation and high-frequency deep convection. Second, all simulations overestimated precipitation isotopic ratios in the East Asia summer monsoon region due to low precipitation in the region caused by a shift in the moisture convergence zone from eastern China to the western Pacific Ocean. Third, in cold continental regions such as Siberia, Greenland, and Antarctica, the model had a positive bias in precipitation isotopic ratios due to a moisture bias and a low temperature effect; these regions also had a large positive bias in terms of precipitation deuterium excess. A particularly large bias was observed in ice clouds with low ice water content, indicating uncertainties in the vapor deposition process. Together, these results suggest that stable water isotopes are helpful for identifying biases associated with cloud microphysics and the atmospheric hydrological cycle. The unique constraints of stable water isotopes revealed cloud microphysics uncertainty and biases in the hydrological simulations.
Causal Orthogonal Functions: A Causal Inference approach to temporal feature extraction
Authors: Reiter Nicolas-Domenic , Runge Jakob , Gerhardus Andreas
Published: March 2022

Understanding complex dynamical systems is a major challenge in many scientific disciplines. There are two aspects which are of particular interest when analyzing complex dynamical systems: 1) the temporal patterns along which they evolve and 2) the governing causal mechanisms.

Temporal patterns in a time-series can be extracted and analyzed through a variety of time-series representations, that is a collection of filters. Discrete Wavelet and Fourier Transforms are prominent examples and have been widely applied to investigate the temporal structure of dynamical systems.

Causal Inference is a framework formalizing questions of cause and effect. In this work we propose an elementary and systematic approach to combine time-series representations with Causal Inference. Hereby we introduce a notion of cause and effect with respect to a pair of arbitrary time-series filters. Using a Singular Value Decomposition we derive an alternative representation of how one process drives another over a specified time-period. We call the building blocks of this representation Causal Orthogonal Functions. Combining the notion of Causal Orthogonal Functions with a Wavelet or Fourier decomposition of a time-series yields time-scale specific Causal Orthogonal Functions. As a result we obtain a time-scale specific representation of the causal influence one process has on another over some fixed time-period. This allows to conduct causal effect analysis in discrete-time stochastic dynamical systems at multiple time-scales. We illustrate our approach by examining linear VAR processes.
Mesozoic titanite U–Pb age from mafic granulites of the Wuhe Complex, southeastern North China Craton (NCC)
Authors: Kong Xu , Lu Jun-sheng , Liu Gang , Feng Qiang , Li Yu-ting , Zhang Yi-yi
Published: March 2022

As an important component of the lower crust, mafic granulites can provide a great deal of information about orogens’ metamorphic and tectonic evolution, and thus are studied extensively. According to the previous studies, the Wuhe Complex experienced the Late Paleoproterozoic metamorphic event. Here, we report the newly discovered Mesozoic metamorphic titanite age from the mafic granulites of Wuhe Complex and provide some clues to the Mesozoic metamorphic event of the southeastern NCC. Mafic granulite (sample 20BB44) is composed of garnet (12–15 vol.%), clinopyroxene (30–35 vol.%), hornblende (3–6 vol.%), plagioclase (40–50 vol.%), and quartz (1–2 vol.%) with minor ilmenite, pyrite, apatite, zircon, and titanite. Titanite grains are subhedral, euhedral, or homogeneous with grain sizes of 50–300 μm, and have inclusion minerals of hornblende, plagioclase, quartz, and ilmenite. Titanites have variable contents of U (1.0–17.2 ppm), Th (0.2–29.6 ppm), Pb (2.2–6.5 ppm), and Zr (20–259 ppm) with Th/U ratios of 0.07–4.53. According to the Zr-in-Titanite thermometer (Hayden et al., 2008: the estimated pressure was assumed as 0.5 GPa, and the activity of SiO2 (αSiO2) and TiO2 (αTiO2) were assumed as 1 and 0.8, respectively), the titanites may form at the temperature of 607–725 ℃ (689 ℃ on average). Thirty analysis spots on 29 titanite grains yield a lower intercept U–Pb age of 163 ± 28 Ma (MSWD = 1.17). Titanite U–Pb age of 163 Ma may represent the Mesozoic metamorphic event of southeastern NCC and may relate to the subduction of the Paleo-Pacific plate.
On the influence of shallow geothermal energy on the behaviour of contaminants of emerging concern
Authors: Pujades Garnes Estanislao , Jurado Anna , Scheiber Laura , Teixidó Marc , Criollo Rotman , Vilarrasa Victor , Vázquez-Suñé Enric
Published: March 2022

Pressure over water resources is increasing rapidly as a result of climate change and growing population. In this context, urban aquifers emerge as a valuable resource of fresh-water for cities. However, the quality of urban groundwater is degraded due to the presence of contaminants of emerging concern (CECs) that reach continuously urban aquifers from different recharge sources. The effects of CECs are largely unknown, but it is expected that they pose a risk for human health, soil, plants and animals. CECs are naturally degraded in aquifers and their degradation rates depend on the physico-chemical conditions (i.e., redox conditions and water temperature) of the groundwater, which may vary as a result of anthropogenic activities. Therefore, it is needed to establish the impact of anthropogenic activities on CECs to determine their behaviour under modified and variable physico-chemical conditions and allow the safely use of urban groundwater. One of these anthropogenic activities that potentially modify the physico-chemical conditions is the use of the subsurface to obtain cooling and heating energy through low-enthalpy geothermal energy (LEGE) systems. LEGE is a renewable and carbon-free energy whose utilization is currently growing. Thus, it is expected that in a near future the density of LEGE systems will increase over most cities. Then, our objective is to determine the impact of LEGE systems on the behaviour of CECs.

We have investigated the behaviour of CECs under the influence of LEGE by means of numerical models and considering different representative scenarios. The results show that the physico-chemical variations induced by LEGE systems modify notably the degradation rates of CECs, and thus, their concentrations on the downgradient side. Our results have significant implications for predicting the behaviour of CECs in urban aquifers and suggest the possibility of specifically design LEGE systems to improve in a passive way the quality of urban groundwater by eliminating CECs.
Particle Laden Gravity Currents dynamics in highconcentration regimes
Authors: Schneider Jean , Dossmann Yvan , Delcey Mickaël , Cheny Yoann , Kiesgen De Richter Sébastien
Published: March 2022

LEMTA - UMR 7563 CNRS-UL - Universite de Lorraine, Nancy, France

Particle-laden gravity currents (PLGC) are commonly found in estuaries
where rivers discharge suspended matters into the oceans. The dynamics of
these stratified flow is largely related to the properties of the suspended particles, such as their geometry, concentration, and particles size. While several
studies have focused on low concentration regimes (e.g. [1]), the physical mechanisms controlled by particle size and concentration are largely unknown for
volume fraction larger than 2 %.

In order to investigate how the dynamics of PLGC is influenced by particle
concentration and particle size in high concentration regimes, we study the impact of different particle sizes ranging from 6µm to 85µm.

The experimental lock-release device is composed of a tilted tank at a controlled angle in which a particle loaded fluid is released on an environment with
a controlled density. A particular focus is put on hypopycnal freshwater currents with high concentration suspended particles advancing through a heavier
environment. We follow the progress of the current with a high frequency CCD
camera. Quantitative data can then be determined using optical methods such
as Light Attenuation Technique which is extended to multiphase flows.

Different flow regimes are observed depending on the concentration range and
particle size. These regimes highlight the competition between advective transport controlled by density difference and convective sedimentation. Indeed four
mechanisms are observed in these regimes, respectively horizontal advection at
the surface, sedimentation, advection parallel to the tank bottom, and particle
rise of due to buoyancy effects of the surrounding fluid.

References
[1] Bruce R. Sutherland et al. “Particle settling from constant-flux surface
gravity currents and a near-stationary particle-bearing layer”. In: Physical
Review Fluids 6.6 (June 10, 2021). Publisher: American Physical Society,
p. 063802. doi: 10 . 1103 / PhysRevFluids . 6 . 063802. url: https : / /
link . aps . org / doi / 10 . 1103 / PhysRevFluids . 6 . 063802 (visited on
10/25/2021)
Spotting C2H4 in forest soils- what influences the occurrence of the phytohormone? 
Authors: Lang Verena , Schneider Veronika , Schengel Alexander , Schäffer Jürgen , Schack-Kirchner Helmer , Maier Martin
Published: March 2022

As a reactive gaseous hydrocarbon, the phytohormone ethylene (Ethene, C2H4) influences root growth, senescence, and fruit ripening. While plants produce ethylene, microorganisms and fungi are also capable of degrading it. Ethylene therefore acts as an indicator for soil biological processes, but due to its reactivity it is hardly detectable in the atmosphere and soil air. In the 1970s to 1990s, studies were able to demonstrate that up to several ppm of C2H4 occur in soil under certain conditions. However, these studies were limited to laboratory experiments and have a limited transferabilty to undisturbed forest soils.

We investigated the occurrence of ethylene as well as the influencing environmental parameters in forest soils in southwestern Germany using long-term measurement series from the Forest Environmental Monitoring (ICP Forests), as well as from project studies over the past 30 years. In total, soil gas data were available from 24 sites covering a period from 1994 to 2021. Data from gas samplers were used which were installed at various soil depths, at which the soil gas concentration was determined at regular intervals.

The data analysis showed that ethylene in the forest soil very rarely reached the detection limit of our highly sensitive gas chromatography system and that the occurrence is not subject to a regular temporal pattern, but rather cluster in hotspots and hot moments. Ethylene is measured far more frequently under spruce than under deciduous trees. The observed tree species effect indicates a correlation between rooting intensity and ethylene occurrence, as revealed by the evaluation of the root profiles. Artificial soil compaction also leads to increased ethylene concentrations, whereas no effect of liming could be observed.

Thus, the extensive field measurements confirm the patterns known from laboratory studies and show that ethylene, despite its rare occurrence in forest soils, is potentially found at all sites. The accumulation of ethylene in soil air could be observed significantly more frequently in compacted soils than in well-aerated forest soils, where the faster exchange with ethylene free atmospheric air makes accumulation and thus detection difficult.
Response of soil moisture to rainfall reduction under different grassland species: preliminary results of a rainfall exclusion experiment under a Mediterranean climate
Authors: Milazzo Filippo , Colesanti Michele , Leal Murillo Ramon , Fernández Habas Jesús , Fernández Rebollo Pilar , Vanwalleghem Tom
Published: March 2022

Permanent grassland (PG) covers about 30% of the cultivated area of Europe, and 5 x 108 ha of them are in the Mediterranean zones. Climate change and prolonged drought seasons can expose PG’s soils to bare conditions for a long time, raising the land degradation risk, and diminishing food delivery to cattle. The objective of this study is to measure the response of soil moisture to a reduction in rainfall in different grass species. A rainfall exclusion experiment was set up to intercept 30% of the natural rainfall in Cordoba, Spain. Soil moisture was measured in 18 plots of 2 m2, of which 9 were under exclusion and 9 under natural rainfall. We used a Drill and Drop Sentek soil moisture probe, measuring between 0 – 30 cm depth, from 1/11/21 until 27/01/22. We also measured phenological plant response.  Average soil moisture was clearly lower in the reduced rainfall plots. These results will contribute to understand the effect of future climate on soil moisture, grass response and agricultural food security in the region. In particular, it will help farmers to select the species that best resist drought conditions.
Seasonal compartmentalisation of water in a grassland at 2600 m a.s.l.
Authors: Gentile Alessio , Bevilacqua Ivan , Canone Davide , Ceperley Natalie , Gisolo Davide , N'Sassila Mesmer , Previati Maurizio , Zuecco Giulia , Schaefli Bettina , Ferraris Stefano
Published: March 2022

High Alpine catchments are precious water-resources since they act as natural storage reservoirs, storing water in the snow cover and in the subsurface and thereby providing water during the dry seasons. Thus, a deeper knowledge of the hydrological functioning of these systems is necessary, in particular to make climate change projections. The role of seasonality is crucial in these catchments that generally exhibit a snow-dominated hydro-climatic regime.

Here we use high-frequency observations of stable isotopes of water to identify the seasonal origin of streamwater in a high-elevation Alpine catchment located in the Valle d’Aosta Region, Italy. We quantify the relative contribution of winter and summer precipitation reaching the stream through the Seasonal Origin Index (SOIQ), calculated using the δ18O values and the volumes of precipitation and streamflow. Highly negative SOIQ values are obtained suggesting that streamwater is mainly composed of winter precipitation. Conversely, the Seasonal Origin Index for evapotranspiration (SOIET), which can be directly inferred from SOIQ, returns a positive value reflecting that plants preferentially take up water deriving from summer precipitation.

These findings allow us to develop a conceptual model of this Alpine system. This conceptual model suggests:

a deep infiltration component, mainly composed by snowmelt water, reaching the stream through a preferential flow.

a shallow infiltration component, predominantly represented by summer rainfall, that dominates the shallow soils and that is used by plants.

Therefore, we presume a seasonal compartmentalisation of water in this high-elevation catchment.

Nevertheless, a previous study in Switzerland revealed SOIQ ≈ 0 for the Allenbach and Dischmabach snow-dominated catchments, indicating that similar fractions of summer and winter precipitation become streamflow. This different result achieved in systems with an apparently similar functioning highlights the need for a deep insight into the flow paths governing high-elevation catchments and it opens the way for new challenges to understand the hydrological processes hidden behind this difference.
Stakeholder interpretation of probabilistic representations of uncertainty in spatial information: an example on the nutritional quality of staple crops
Authors: Chagumaira Christopher , Nalivata Patson , Chimungu Joseph , Gashu Dawd , Broadley Martin , Milne Alice , Lark Murray
Published: March 2022

Spatial information, inferred from samples, is needed for decision-making but is uncertain. One way to convey uncertain information is with probabilities (e.g., that a value falls below a critical threshold). We examined how different professional groups (agricultural scientists or health and nutrition experts) interpret information, presented this way when making a decision about interventions to address human selenium (Se) deficiency. The information provided was a map, either of the probability that Se concentration in local staple grain falls below a nutritionally-significant threshold (negative framing) or of the probability that grain Se concentration is above the threshold (positive framing). There was evidence for an effect of the professional group and of framing on the decision process. Negative framing led to more conservative decisions; intervention was recommended at a smaller probability that the grain Se is inadequate than if the question were framed positively, and the decisions were more comparable between professional groups under negative framing.  Our results show the importance of framing in probabilistic presentations of uncertainty, and of the background of the interpreter. Our experimental approach could be used to elicit threshold probabilities that represent the preferences of stakeholder communities to support them in the interpretation of uncertain information.