bluuebunny/crossref_metadata_2025 huggingface dataset:
Bayesian modeling of velocity break points in GNSS time series and the effect of noise on their estimation: Did velocity anomalies in the Krafla volcanic system, north Iceland, precede the Bárðarbunga-Holuhraun 2014-2015 rifting episode?
Authors: Yang Yilin , Sigmundsson Freysteinn , Geirsson Halldór , Lanzi Chiara , Hreinsdóttir Sigrún , Drouin Vincent , Zhou Xiaohui , Ma Yifang
Published: February 2023

Correct estimation of the timing of velocity changes (break points) and associated uncertainties in ground deformation observed with Global Navigation Satellite System (GNSS) coordinate time series is crucial for understanding various Earth processes and how they may couple with each other. To simultaneously estimate break points, velocity changes and their uncertainties, we implement Bayesian modeling with Markov Chain Monte Carlo algorithm for GNSS time series. As the presence of white noise (WN) and time-correlated flicker noise (FLN) in GNSS time series was found to affect velocity estimation, synthetic data experiments are first conducted to investigate their effect on break point estimation. The results indicate that reliable estimates are obtained only when the value of velocity change is larger than FLN amplitude. With the presence of WN and FLN, whose amplitudes are one twentieth and one fourth of the velocity-change value, the estimation bias and uncertainty are <0.5 mm/yr and ~5 mm/yr for velocity change, and <30 d and ~100 d for break point, respectively. In this case the uncertainty is one magnitude larger than that with only the presence of WN. Then the proposed method is applied to model two velocity changes detected manually during 2014-2015 at the Krafla volcanic system, North Volcanic Zone (NVZ), Iceland. Similar accuracy and precision as the synthetic data experiments can be expected in east component of the real data as the velocity-change values are 6.9-16.5 times of the WN amplitudes and 2.5-4.0 times of the FLN amplitudes from preliminary analysis. Considering the uncertainty estimated with 95% confidence interval, the first break point at the three continuous GNSS stations in the Krafla area suggests a change in extension pattern across the NVZ prior to the beginning of a major rifting episode that started on 16 August 2014 at the Bárðarbunga volcanic system, which is ~130 km south of Krafla. The first break point at KRAC station in the Krafla caldera occurs on 2-4 July 2014, with 95% confidence interval being 4 May to 13 August 2014. The first velocity change is about 7.6 to 9.8 mm/yr to the west with its uncertainty ranging from 4.5 to 14.4 mm/yr. The velocities approximately resume to the original level after the second change at the end of 2014 or early 2015, whose chronological relationship with the end of Bárðarbunga-Holuhraun episode cannot be asserted because of uncertainties. The results may indicate coupling of activities between the volcanic systems in the NVZ via processes not well understood. Further work is needed to confirm these results and their significance.
For a sustainable future: a survey about geoethics and 2030 Agenda among the Italian geosciences community
Authors: Egidio Elena , Gerbaudo Andrea , Lasagna Manuela , Lozar Francesca , Tonon Marco Davide
Published: February 2023

The annual Congress of the Società Geologica Italiana (SGI) and Società Italiana di MIneralogia e Petrologia (SIMP), held in Turin in September 2022 and dedicated to Geosciences for a sustainable future, has been the occasion to critically think on the role of the Geosciences for our society and planet, on the position geoscientists deserve and the role they must take in the formation of citizens, protection from natural hazards and preservation of cultural and natural heritage. In continuation of our previously published work Are we ready for a sustainable development? A survey among young geoscientists in Italy , the present study broadens the sample analyzed to include the entire Italian community of geoscientists and aims to highlight: 1) The relevance of the ethical aspects connected to the work of professionals and scholars, in accordance with the values of geoethics; 2) the most widely held views about the connections between the Earth Sciences and the 17 Sustainable Development Goals of the UN 2030 Agenda; 3) which initiatives have been put in place by Italian Earth Sciences departments on education for sustainability and which can be the best strategies for developing sustainability education related to geoscience issues. Based on 230 answers to a questionnaire with open and closed questions sent to the participants at the Congress, the results show that the Italian geocommunity has great awareness of the ethical implications of its work and research, in particular of the responsibility towards the environment; despite this consciousness, the average level of knowledge about the 2030 Agenda and its goals is still scarce. To fill this gap, the need for sustainability education initiatives in departments is recognized as urgent, as well as the use of inter- and transdisciplinary educational approaches that can train scholars and professionals capable of addressing the complex challenges of our time.
Low-cost sensor system for measuring ambient nitrogen compounds in agricultural areas
Authors: Fabius Jasper H. , Celikkol Burcu , Rai Upasna , Vonk Jan , Suer Remco , Zhuang Shaojie
Published: February 2023

Nitrogen compounds such as nitrogen dioxide (NO2) and ammonia (NH3) contribute significantly to air pollution and environmental degradation. Fine-grained networks of sensors for ambient nitrogen compounds can be used to inform policy makers and farmers about the effectiveness of techniques to reduce emissions of nitrogen compounds. We are developing a low-cost self-sustaining sensor system that can be deployed outdoors in large numbers in and around agricultural areas to measure the concentration of NH3, NO2, temperature and humidity with a high spatiotemporal resolution. We use off-the-shelf electrochemical sensors to measure nitrogen compounds. A preliminary comparison between the NH3 measurements taken by our sensor system and by a differential optical absorption spectroscopy instrument (miniDOAS) demonstrate encouraging results. After calibration, the measurements from our system show fairly good agreement with hourly-averaged miniDOAS measurements, at concentrations down to ~20 µg/m3. We are currently setting up a larger validation study to further assess the performance and robustness of our system in different outdoor agricultural environments. Our sensor system has the potential to greatly expand the availability and affordability of NH3 monitoring across wide areas, enabling farmers and policymakers to gain insights on the effectiveness of potential nitrogen reduction measures.
A multidisciplinary workflow to assess seismic hazard by active and capable faults when planning railway lines
Authors: Bonini Selina , Viola Giulio , Tartaglia Giulia , Rodani Stefano , Comedini Massimo , Vignaroli Gianluca
Published: February 2023

The planning phase of a railway line has to carefully consider the potential impact of several geohazards, including the seismic hazard associated with active faults capable to cause significant offset (dm to m) of the ground surface. Italian authorities are investing large resources in the construction of new railway lines in Italy, which is a territory that stands out as high-risk due to the presence of active faults, including those accommodating extension within the Apennines belt. Numerous seismogenic sources have been recognized therein by the geophysical and geological community over the last few years. Their identification and characterization represent the foundation of the seismic hazard map of Italy, which is regularly used to assess the seismic hazard of any given area of the country. Active and Capable Faults (ACFs) may contribute to increasing the seismic hazard of an area, though, and may interfere with railway lines. Following the Italian guidelines for the seismic microzonation procedures, an ACF is capable of producing, within a time interval of concern the society, macro-earthquakes and deformation/displacement at or near the ground surface and should have done so during the last 40 ka (upper Late Pleistocene – Holocene).We propose a multidisciplinary workflow for improving and standardizing the use of the existing Italian geohazard databases. As the area covered by a railway line may extend for tens or hundreds of kilometers, it is crucial to define systematic criteria that make it possible for the intersected ACFs to be sorted into classes of varying hazard, each requiring different approaches and study levels. The seismicity associated with the ACF’s, the fault geometric and kinematic compatibility with the current regional tectonic setting and stress field, the involvement of < 40 ka old rocks and sediments, the proximity to the ground surface of the historical hypocenters, the geometrical relationships between the ACF’s and the orientation of the railway line are just a few of the aspects to be considered by such an approach.We aim to define and constrain all the input parameters necessary to perform site-specific fault displacement and seismic hazard analysis, since the currently available Italian seismic hazard map is still too coarse in its resolution (with PGA values every 10 km). Our new approach will allow us to include the detection of near-field effects (e.g., the increasing of the vertical component due to seismic acceleration, forward-directivity phenomena, co-seismic rotation) if the trailway line runs within a 15 km zone from the main fault plane.Knowing ACFs behavior will make it possible, during the planning, to choose the best railroad options, in order to reduce the vulnerability of the planned infrastructure.
Uncertainty in estimation of Soil Hydraulic properties and root zone state variables in inverse method
Authors: Gupta Vaibhav , Muddu Sekhar
Published: February 2023

Soil hydraulic parameters such as residual water content, saturated water content, hydraulic conductivity, are key factors to be considered when assessing the soil capabilities to provide ecosystem services. Proper computation of fluxes from vadose zone using the hydrological models strongly depends on correct estimation of input parameters, process scale, boundary, and initial conditions. Estimation of soil parameters for many hydrological models is always an arduous task due to uncertainty bounded with parameters. Over the last few years many researchers have favoured to estimate the parameters using inversion approach due to increasing computing capabilities and easily measurable output variables. The current study deepens the understanding of the soil hydraulic parameter estimation using inversion approach. The inversion was conducted on synthetic data set using the SWAP (Soil water atmosphere and plant) model along with the GLUE (Generalized Likelihood Uncertainty Estimation) algorithm. Several constrain variables, able to be derived from remote sensing or in-situ measurements (Leaf Area index - LAI, Evapotranspiration – ET and Surface soil moisture – SSM), were used in the inversion process alone or in different combinations. The current study uses the two types of soil profile, homogenous soil system and two layered soil system. In this synthetic experiment, we compared the effect of different soil type, different surface conditions, different water conditions, and frequency of observed variables on parameter estimation. Effect of initial predefine range of the parameter space, on SHP estimation, were also investigated. Use of DSM data to define the initial range of parameter space were also investigated. We also simulated the state variables with uncertainty using the estimated parameters. Main outcomes could be reported when retrieving the SHPs, retrieval was significantly correlated with soil type and water stress condition, although overall retrieving performances were quite poor specially in layered soil system. We could identify some promising combinations of constrain variables for better estimation of parameter in different soil types. Our approach may further provide spatial sampling of DSM data components to improve the SHPs estimation, to be used as surrogate input for defining the initial range.
Effects of background solar wind on the propagation of coronal mass ejection driven shock
Authors: Wu Chin-Chun , Liou Kan , wood Brian , Hutting Lynn
Published: February 2023

Propagation of interplanetary (IP) shocks, particularly those driven by coronal mass ejections (CMEs), is still an outstanding question in heliophysics and space weather forecasting. Here we address effects of the ambient solar wind on the propagation of two CME-driven shocks from Sun to Earth. The two CME-driven shock events (CME03: April 3, 2010 and CME12: July 12, 2012) have the following properties: (1) driven by a halo CME (i.e., source location is near Sun-Earth line), (2) a southern hemispheric CME source location, (3) similar propagation speed (e.g., took ~2 days reach the Earth), (4) occurred in the non-quiet solar period, and (4) leading to a severe geomagnetic storm. What is interesting is that the initial (near the Sun) propagation speed, as measured by coronagraph images, of CME03 was slower (~300 km/s) than CME12, but it took about same time for both events to reach the Earth. According to in-situ solar wind observations from Wind, the CME03-driven shock was associated with a faster solar wind upstream of the shock than the CME12. This is also demonstrated in our global MHD simulations. This study emphasizes the importance of the background solar wind in the propagation of CME-driven shocks. Not only the initial propagation speed near the Sun but also the ambient solar wind speed is the key to timing the arrival of CME events. The present study also demonstrated that global MHD simulations with realistic solar wind inputs is able to precisely predict the arrival of CME events.
The importance of anaerobic oxidation of methane in thermokarst lakes
Authors: Sivan Orit , Pellerin André , Lotem Noam , Eilani Russak Efrat , Gerera Yarden , Walter-Anthony Katey
Published: February 2023

About 40% of the annual methane emissions originate from natural, non-anthropogenic sources. These include mainly freshwater sediments, in which significant increase in methane emissions has been observed throughout the past decades with the ongoing global temperature rise. Thermokarst lakes, formed by abrupt thawing of permafrost, play a significant role in this observed increase in methane emissions. However, methane production rates and natural consumption controls there are not well constrained, as well as their response to global warming.  We explore the rates and mechanisms of methane production and anaerobic oxidation (AOM) processes several interior Alaska thermokarst lakes, which formed and continue to expand as a result of ice-rich permafrost thaw. This is mainly through geochemical and microbial profiles combined with slurry incubation experiments with labeled isotopes, potential electron acceptors and several inhibitors in different temperatures. Our manipulated experiments shed insight on the controls of methanogenesis onset and the mechanisms of both methanogenesis and AOM. Direct rate measurements using two isotope methods and modeling provide robust rate estimations for methanogenesis and AOM. They indicate that the role of AOM in these lakes is less significant than previous estimations, and that AOM will probably not attenuate the methanogenesis increase in a warmer climate. 
Teaching science, sustainability and technology through gamification: The approach of escape rooms.
Authors: Alexandropoulou Angeliki , Tsezou Athina –Spyridoula
Published: February 2023

Gamification is a pedagogical strategy that introduces principles of gaming in learning environments by promoting participation and enhancing motivation. The literature indicates that whenever students are involved in playful educational experiences, motivation is significantly increased compared to the typical educational activities while emotional intelligence and well-being are also cultivated. Studying in a distraction-free atmosphere helps students foster a positive attitude towards learning as they can study and participate at their own speed, free of peers and teachers pressure.Escape rooms as a didactic tool in teaching and learning is still in its nascent stages, but recent researches have proven that it does not just offer students’ exposure to technology but a higher level of critical thinking, decision making under time constraints, communication, creative innovation, confidence and collaboration amongst peers.My colleagues and I are involved in a project that gives the students of our school the opportunity to participate in creating and promoting escape rooms as a learning activity in order to present a different teaching approach. The context varies among science, environmental problems, sustainability, geography, space, math and technology. We combine the team based learning method and the project based method in order to study each topic, collect information, write a story, create relative puzzles and include them in each escape room. When digital escape rooms are ready, teams exchange their links trying to solve them and accomplish their missions. In this way, students are involved in different topics and obtain knowledge by exploring, creating and collaborating. All of the above is going to be presented to our poster.
Preliminary results from global modelling of Cirrus Cloud Thinning in the Geoengineering Model Intercomparison Project
Authors: Smith William , Visioni Daniele , Hunt Hugh
Published: February 2023

Cirrus clouds have a net positive radiative forcing effect on the climate, leading to the suggestion of cirrus cloud thinning (CCT) as a means to ameliorate global warming. By deliberately thinning cirrus clouds, more longwave radiation is able to escape the Earth system into space, cooling the planet. CCT has been modelled as part of the Geoengineering Model Intercomparison project in the G7cirrus experiment. Given the complexities of cirrus cloud modeling, to obtain similar results across different models this experiment simulates CCT by increasing the fall seed of ice crystals in cirrus clouds. This is carried out against a SSP5-8.5 scenario background, beginning in 2020 and ending in 2100. So far, G7cirrus has been run in two Earth System Models: UKESM1 and IPSL. Here, we look at some preliminary results from this experiment, such as analysing the intervention’s effective radiative forcing and its impact on different climate variables such as air temperature and precipitation.
Analysis of the impact of climate change on grapevines in Turkey using heat unit accumulation–based indices
Authors: An Nazan , Turp M. Tufan , Orgen Bora , Bilgin Başak , Kurnaz M.Levent
Published: February 2023

Temperature is the most important factor influencing grapevine phenology and yield. Various indices have been developed that deal with the temperature sums that grapevines are exposed to during growth and maturation. With the help of these indices, predictions are made about whether the grapes will grow in a certain region and the quality of the grapevines. In this study, the future impacts of climate change on viticultural conditions in Turkey were projected by using Huglin index (HI), Winkler index (WI), and cool night index (CI). Under the RCP8.5 scenario, HI, WI, and CI indices for the future period of 2022–2050 were calculated for Turkey at 10 km spatial resolution with the RegCM4.4 model and compared with the 1972–2000 reference period. As a result of the study, a substantial increase in CI, HI, and WI and at least one level of categorical change were observed in the climatic conditions of the next 30 years in Turkey. These categorical shifts in CI, HI, and WI indicate that there may be changes in the geographical pattern of grapevine species grown in Turkey as well as the aroma and quality.Acknowledgement: This research has been supported by Boğaziçi University Research Fund Grant Number 17601 
Climate change mitigation and SDGs: modelling the regional potential of promising mitigation measures and assessing their impact on other SDGs
Authors: Dagnachew Anteneh , Hof Andries
Published: February 2023

Measures that aim to reduce greenhouse gas emissions also have impacts on achieving other Sustainable Development Goals (SDGs). Given the enormous challenge of achieving the goals of the Paris Agreement and the SDGs, insight into these impacts provides information on how to improve feasibility of climate change mitigation measures by maximizing the co-benefits and managing the risks of possible trade-offs across SDGs. In this paper, we explore the impact of twenty promising climate mitigation measures on achieving the other SDGs for eleven world regions. Using the IMAGE modelling framework, the paper explores the GHG emissions reduction potential of these measures aggregated by sector under three scenarios. Based on peer-reviewed articles, the impact of the measures on other SDGs is assessed for the top three sectors with the highest GHG reduction potential in each region. We conclude that the number of synergies between the selected climate change mitigation measures and other SDGs dwarf the number of trade-offs in all regions. The magnitude of these synergies and trade-offs, however, varies by regional and socio-economic context. In high- and middle-income regions, the mitigation measures show few trade-offs that are generally associated with technology choices that could aggravate inequality and impact biodiversity. In low-income regions, some measures, especially land-use related ones, could interfere with efforts to reduce poverty, end hunger and improve well-being, if not complemented by additional policies that aim to protect the poor from increasing food and energy prices.
Partitioning the urban carbon budget with carbonyl sulfide (COS) flux measurements conducted in a high-latitude city
Authors: Soininen Jesse , Rantala Pekka , Kulmala Liisa , Järvi Leena
Published: February 2023

Globally, cities correspond to most of the direct anthropogenic carbon emissions, and due to the global mega-trend of urbanization, their importance will only increase. The carbon budget of an area is often given as a net ecosystem exchange (NEE), which describes net CO2 fluxes measured with eddy covariance (EC) method. However, these measurements alone cannot partition anthropogenic and biogenic carbon sources and sinks. Earlier studies on vegetated ecosystems have defined leaf-scale relative uptake (LRU) of carbonyl sulfide (COS) and CO2 to partition the biogenic uptake, namely gross primary production (GPP). In this research, the aim was to examine the suitability of using COS flux measurements to partition GPP from urban NEE, to better understand the effect of urban green areas on the carbon balance of cities. EC fluxes of CO2 and COS were measured at ICOS Associated Ecosystem Station FI-Kmp station in Helsinki, Finland, during Winter 2020-2021 and July 2022. Urban LRU is estimated for a footprint dominated by urban parks. Then, GPP is estimated from the measured COS flux, using three methods with varying complexity, for more heterogeneous footprints with more pronounced anthropogenic influence. Estimates are compared with a more common carbon balance partitioning method where only ecosystem respiration is considered.Preliminary results showed how LRU over urban park has similar behavior as forest LRU, and the values are same order of magnitude. COS flux can be used as a tracer for carbon uptake by photosynthesis also in urban areas. Two out of the three methods showed the daily dynamics of GPP qualitatively right, with more complex underestimating and simpler overestimating the GPP, respectively. When using COS as a proxy for GPP in a heterogeneous urban environment, errors arise due to anthropogenic emissions of COS, which are not expected in the original context of using the compound as a biogenic activity tracer. In the future, more focus will be put to adapt methods to determine anthropogenic influence.
Understanding the hydrological response of groundwater discharge from freezing soils to a warming climate
Authors: Devoie Élise , McKenzie Jeffrey , Lamontagne-Hallé Pierrick , Woo Audrey
Published: February 2023

Objective: Estimate the error introduced by the misrepresentation of soil freezing characteristic curves (SFCCs) in hydrological models and propose an improved method for modelling freezing soils.Key FindingsMost SFCCs used in numerical modelling studies are chosen based on convergence behaviour as opposed to physical soil properties.
The choice of SFCC affects model outcomes, including governing the ice content of soils, which in turn controls the permeability and the discharge from a hydrogeologic model.
AbstractMore than half of the global terrestrial surface is subject to freezing processes, either as seasonally frozen soils or as permafrost. Soil freezing processes are represented by the soil freezing characteristic curve (SFCC) that relates soil temperature to its unfrozen water content. Unfortunately, SFCCs are frequently misrepresented in models, and often chosen based on ease of model convergence behavior as opposed to physical soil properties. With climate change and increased frequency of midwinter melt, SFCCs are becoming increasingly important in accurately predicting the hydrological response of catchments.Two synthetic hillslopes, one for a permafrost system and one for a permafrost-free system affected by seasonal freezing, are simulated using SUTRA-ice and a selection of widely accepted SFCCs. SFCCs are drawn from literature values as well as a repository of collected SFCC data: "A Repository of 100+ Years of Measured Soil Freezing Characteristic Curves". The resulting discharge is compared for each simulation, showing that the choice of SFCC is important in controlling streamflow generation in these landscapes, and the choice of SFCC may be a previously overlooked controlling process in the hydrological behaviour of catchments with freezing soils. Further work upscaling these results to catchment and larger scales is needed.
Measuring the pore size distribution of a soil sample during the saturated triaxial compression using non-Newtonian fluids
Authors: Lanzendörfer Martin , Roháč Jakub , Slavík Martin , Weiss Tomáš , Najser Jan
Published: February 2023

While there are many methods available for the characterization of pore space of soils, most of them are not suitable for observing the gradual changes of the pore sizes of a given sample during the process of its compaction. Non-Newtonian fluids have been utilized recently for approximating the pore size distribution, providing not only a cheaper and more accessible alternative to the classical porosimetry techniques but also a method that allows to keep the sample undisturbed and to be used repeatedly. In particular, the so-called ANA method [1] computes the effective pore size distribution based on a set of saturated flow experiments with different shear-thinning fluids, such as the aqueous xanthan gum solutions of different concentrations.We will discuss a methodology to measure the progressive changes in the pore size distribution of the sand sample placed in the standard triaxial test chamber where it is subject to a drained compression. After every compression step (i.e. after increasing the pressure level maintained in the chamber, thus further compacting the sample), a sequence of permeability measurements with fluids of different rheology is performed and the effective pore size distribution is approximated. The ANA approach is used in our case since the similar yield-stress method [2] requires using larger hydraulic gradients, which would disturb the effective stress imposed on the compressed sample.[1] Hauswirth, S.C., Abou Najm, M.R., Miller, C.T., 2019. Characterization of the Pore Structure of Porous Media Using non-Newtonian Fluids. Water Resources Research 55, 7182–7195. https://doi.org/10.1029/2019WR025044[2] Rodríguez de Castro, A., Agnaou, M., Ahmadi-Sénichault, A., Omari, A., 2020. Numerical porosimetry: Evaluation and comparison of yield stress fluids method, mercury intrusion porosimetry and pore network modelling approaches. Computers and Chemical Engineering 133. https://doi.org/10.1016/j.compchemeng.2019.106662 
Exploring solar-terrestrial interactions via multiple imaging observers
Authors: Branduardi-Raymont Graziella
Published: February 2023

How does solar wind energy flow through the Earth’s magnetosphere, how is it converted and distributed? This are the questions we want to address. We need to understand how geomagnetic storms and substorms start and grow, not just as a matter of scientific curiosity, but to address a clear and pressing practical problem: space weather, which can influence the performance and reliability of our technological systems, in space and on the ground, and can endanger human life and health.Much knowledge has already been acquired over the past decades, particularly by making use of multiple spacecraft measuring conditions in situ, but the infant stage of space weather forecasting demonstrates that we still have a vast amount of learning to do. A novel global approach is now being taken by a number of space imaging missions which are under development and the first tantalising results of their exploration will be available in the next decade. In a White Paper, submitted to ESA in response to the Voyage 2050 Call, we propose the next step in the quest for a complete understanding of how the Sun controls the Earth’s plasma environment: a tomographic imaging approach comprising two spacecraft in highly inclined polar orbits, enabling global imaging of magnetopause and cusps in soft X-rays, of auroral regions in FUV, of plasmasphere and ring current in EUV and ENA (Energetic Neutral Atoms), alongside in situ measurements. Such a mission, encompassing the variety of physical processes determining the conditions of geospace, will be crucial on the way to achieving scientific closure on the question of solar-terrestrial interactions.The White Paper was published on 16 August 2021 (G. Branduardi-Raymont et al., Experimental Astronomy, https://doi.org/10.1007/s10686-021-09784-y) and full co-author details are at the end of the article.
Rayleigh-Bénard instability in heterogeneous porous media
Authors: Benhammadi Rima , Hidalgo Juan José , Dentz Marco
Published: February 2023

Convective mixing is present in a large assortment of natural and industrial processes, such as in carbon capture and sequestration, where it ensures a safer storage of carbon dioxide, seawater intrusion, high-level radioactive waste disposal sites and geothermal energy production. In this work, we study the effect of the heterogeneity on the behavior of convective mixing since most of the works that have been conducted so far did not take heterogeneity into consideration.To do so, we consider the Horton-Rogers-Lapwood problem where convection is triggered by a Rayleigh-Bénard instability. Heterogeneity is represented by 2-D multi-Gaussian log-Normally distributed anisotropic permeability fields. We perform a parametric study in which we explore the effect of the variation of the Rayleigh number (Ra), the variance and the correlation length of the permeability field on the fingering patterns, mixing and dissolution fluxes. Mixing is characterized by the scalar dissipation rate and the boundary fluxes. The mixing state is evaluated through the probability density function (pdf) of the concentration and the intensity of segregation. We show the difference in behavior between the dissolution fluxes and the mixing state both for the case of homogeneous and heterogeneous porous media. We observe that convective mixing is enhanced in the case of heterogeneous porous media compared to the homogeneous counterparts.An increase of Ra and of the variance of the permeability field causes a more rapid homogenization of the system and also a decrease in the interface width, the variance of the concentration pdf and the intensity of segregation. For permeability fields with a small correlation length, the effect of the heterogeneity is substantial only for a variance higher than 2. However, for a larger correlation length, this effect is more pronounced and the fingering patterns are no longer smooth but dispersive.Based on these observations, an upscaling of the model based on the effective longitudinal and transverse permeability and the dispersion coefficient is performed.Key words: convective mixing, Rayleigh-Bénard instability, heterogeneity, scalar dissipation rate, dissolution fluxes.
Baseline data as source of uncertainty in large-scale hydrology - a case study
Authors: Kupzig Jenny , Flörke Martina
Published: February 2023

Global hydrological models (GHMs) supply key information for international stakeholders and policymakers, simulating the impacts of the water cycle associated with climate change. Uncertainty in simulation, e.g., linked to climate models, model structure and parameters, jeopardizes valuable decision support. Various scenario data sets have been used, and model‑intercomparison studies have been performed in climate change studies to account for uncertainty linked to climate models and model structure, respectively (Kundzewicz et al., 2018). However, uncertainty in baseline data, used (1) for parameter adjustment of GHMs, and (2) assessment of relative changes in future, has rarely been addressed. Here we show that neglecting the uncertainty related to baseline data can mislead decision-making when assessing the impacts of climate change. We found that three different calibrated versions of the GHM WaterGAP3 (using three different sources of baseline data, namely EWEMBI2b, E-OBS and German Weather Service) reveal contradicting results regarding future streamflow for the German part of the Danube basin. Whereas one data set shows a decreasing 90th percentile of streamflow, indicating less heavy flood occurrence, the other datasets show an increasing 90th percentile of streamflow, indicating the opposite. Although the impact of baseline data (and consecutive parameter estimation) is already present at the mesoscale (Remesan & Holman, 2015), it is often overlooked in climate change studies using GHMs. Our results demonstrate that the choice of baseline data must be considered a source of uncertainty for climate change studies using calibrated GHMs. We anticipate that our study will increase awareness of baseline data's importance and contribute to valuable decision support for international policy related to floods, drought, and human water management.
A New Vs30 Prediction Strategy Taking Topography, Geology, Terrain and Water Saturation into Account: Application to Türkiye and California
Authors: Okay Hakan Bora , Özacar Atilla Arda
Published: February 2023

The time averaged shear wave velocity of the top 30 meters (Vs30) is the most widely used parameter for the geotechnical characterization of site conditions. However, the spatial availability of Vs30 observations are rather limited except specific areas where conducted micro-zonation studies include closely spaced measurements suitable for assessment of earthquake site effects. In order to infer Vs30, global models use slope or morphological terrain classes as proxies. In a regional scale, these proxies are commonly combined with geologic and geotechnical data to improve the accuracy of Vs30 predictions. So far, a region specific Vs30 model that would aid seismic hazard assessments is not yet constructed for Türkiye and its near vicinity. In this study, a new Vs30 prediction strategy is developed using data from Türkiye and California, and its performance is compared with others.At first, Vs30 measurements are classified into 4 sedimentary rock classes according to their ages (Quaternary-Pliocene, Miocene, Paleogene, Pre-Paleogene) and 3 non-sedimentary rock classes (Intrusive, Extrusive, Metamorphic). Observations from Quaternary-Pliocene rocks are most abundant and characterized by large data scatter, thus further divided into 2 major terrain classes. Since the reduction in Vs30 due to fluid saturation is pronounced, especially in unconsolidated young units, Quaternary-Pliocene rocks are also differentiated as saturated if the water table depth is less than 30 meters and unsaturated otherwise. In California, saturation is determined by using available groundwater measurements. Throughout Türkiye, flat areas with elevation differences less than 30 meters from water bodies (sea, lake, and major rivers) are mapped out as saturated zones. After the elimination of outliers, slope and elevation based Vs30 prediction equations are developed separately for sub-classes of Quaternary-Pliocene, Miocene, and Paleocene aged sedimentary rocks using multi-variable linear regression while Vs30 is fixed to class average in others. Resultant model misfits and comparisons with results of micro-zonation study conducted across İstanbul, clearly indicate that our proposed Vs30 prediction strategy is performing better, especially in younger sedimentary units and thus provide a new, more accurate Vs30 model of Türkiye. 
The Stable Isotopes and Geochemical Investigation of Ozvatan Carbonatites (Central Anatolia, Turkey)
Authors: Unluer Ali Tugcan , Budakoglu Murat , Bakkalbasi Ali Erdem , Doner Zeynep , Kocaturk Huseyin
Published: February 2023

The Ozvatan carbonatite complex is located on the Eastern Part of the Central Anatolia, Turkey and host considerable Light Rare Earth Elements (LREE) mineralizations. The carbonatites in Ozvatan complex are mostly coarse grained calcio-carbonatites (sövites) with fluorites and minor opaque minerals. The carbonatites were intruded into silica undersaturated nepheline syenites and caused an intense fenitization process. The calcio-carbonatites of the study are were predominantly enriched in terms of La (up to 995 ppm), Ce (up to 1386 ppm) and Nd (up to 211 ppm). Also some of the LILE’s are enriched including Sr (up to 2%) and Ba (up to 0.75) as expected.  The stable δ13CV-PDB  and δ18OV-SMOW values of the Ozvatan carbonatites represent fractional crystallization and hydrothermal alteration trends. The δ13C values (-6.0 – 4.1 ‰) are generally in tune with worldwide carbonatite range. However, it cannot be concluded as a primary ignous carbonatitic melt due to relatively high δ13CV-PDB values. The  δ18O values (13.3 – 49.3 ‰)  are  also high  mostly cauesed by the high intensity hydrothermal activities (fenitization) or the contamination of meta-carbonate basement rocks. Overall, it can be stated that the, carbonatites of the Ozvatan are products of fractionation of a carbonated silicate melt, low temprature metasomatism and crustal contamination. Keywords: Alkaline Magmatism, Carbonatite, Stable isotopes
Pliocene-Pleistocene evolution of the Agulhas leakage to the Atlantic Ocean
Authors: McClymont Erin , Caley Thibaut , Charles Christopher , Starr Aidan , Sanchez Montes Maria Luisa , West Martin , Rossignol Linda , Hall Ian , Hemming Sidney
Published: February 2023

The Agulhas leakage is an important contributor to the global thermohaline conveyor system, adding warm and saline subtropical waters from the Indian Ocean to the South-east Atlantic Ocean. It has been proposed that weaker Agulhas leakage occurred during glacial stages, but that leakage was reinvigorated during deglaciations and was, in turn, potentially important for the development of interglacial warmth.Little is known about the longer-term evolution of Agulhas leakage during the Pliocene and Pleistocene (the last 5.3 Ma). In the Pliocene, the continental ice sheets were smaller in size, and the position and strength of key ocean and atmosphere circulation systems in the South Atlantic region were different. The Pliocene is also characterised by a series of gateway changes which are argued to have affected North Atlantic climate, but the response of the Agulhas leakage system remains unclear. It is also unclear whether the ‘early deglaciation’ signal is a specific component of the late Pleistocene 100 kyr cycles. Identifying how and when this signal developed could have important implications for understanding the impact of ocean circulation changes on the development of the mid-Pleistocene climate transition (MPT) ~1.2-0.6 Ma, when the period of the glacial-interglacial cycles shifted from ~41 kyr to ~100 kyr.Here we present initial results from a new Cape Basin site (Site U1479, 35°03.53′S; 17°24.06′E), which was recovered by IODP Expedition 361 in 2016 from the western slope of the Agulhas Bank (Hall et al., 2016). We combine reconstructions of sea surface temperatures (using the alkenone-derived UK37’ index) and sea surface salinity (from alkenone dD analysis) with details of planktonic foraminifera assemblages, to identify and understand variability in Agulhas leakage operating across both orbital and longer timescales. There is an overall cooling of ~4°C since the Pliocene, but it is focussed around ~2 Ma and from 1.2 Ma. Orbital scale and longer-term variability in SST, sea surface salinity and Agulhas leakage fauna are also determined, demonstrating that the Agulhas leakage system has evolved across a range of timescales through the Plio-Pleistocene, especially in association with the MPT.ReferencesHall, I.R., Hemming, S.R., LeVay, L.J., and the Expedition 361 Scientists, 2016. Expedition 361 Preliminary Report: South African Climates (Agulhas LGM Density Profile). International Ocean Discovery Program. http://dx.doi.org/10.14379/iodp.pr.361.2
The controlling mechanism of nitrogen dynamics across a large river basin
Authors: Qi Hongkai , Liu Yi , Kuang Xingxing , Luo Xin , Jiao Jiu Jimmy
Published: February 2023

Investigating the dynamics and distribution of nitrogen (N) in river networks is essential for environmental management and pollution control. However, the controlling mechanisms of N dynamics across large watersheds are not well understood. In this study, we examined N concentration and stable isotopes (δ2H-H2O, δ18O-H2O, δ15N-NO3- and δ18O-NO3-) in river water and groundwater through field sampling from 284 sites across the Pearl River Basin, China. Preliminary results show that nitrate (NO3-) is the primary form of riverine dissolved inorganic nitrogen (DIN), and NO3- concentration is three times higher in the groundwater than in river water (mean of  330.5 ± 480.1 μmol/L v.s. 93.2 ± 65 μmol/L). The signature of δ15N-NO3- and δ18O-NO3- indicates that riverine nitrogen is primarily fromsoil organic N. The δ18O-NO3- values ranged from 2.76‰ to 7.52‰, indicating that nitrification is the dominant process in the N cycle of river water across the basin. Denitrification is not apparent in the water column because δ15N-NO3- does not show a negative correlation with NO3- concentration. We find that the source region has the highest NO3- concentration (187.1 ± 16 μmol/L) in river waters. The high cropland proportion (36.5% ± 5%) leads to higher soil N accumulation due to fertilization, and the highest oxidation-reduction potential (222.3 ± 7 mV) indicates the strongest oxidation environment for nitrification. As the nitrification process produces H+, which can consume carbonate and increase dissolved inorganic carbon (DIC), the highest DIC concentration (3139.3 ± 777.5 μmol/L) further proves the most robust nitrification process in the source regions. In conclusion, nitrification can control N dynamics and dominate NO3- distribution in river water in large watersheds.
Effects of the closure of Berlin-Tegel Airport on ultrafine particle concentration on the airport site
Authors: Fritz Sabine , Aust Sebastian , Sauter Tobias
Published: February 2023

Airports contribute significantly to the concentration of ultrafine particles (UFP) at the local level. UFP from combustion processes are produced when aircraft take off and land, during aircraft movements on the tarmac, when turbines are started, but also by vehicles transporting goods and people on the airfield. UFP are considered particularly harmful to human health due to their large surface area. They can also penetrate far into the human body due to their small size.This study examines the extent to which particle number concentration (PNC) responds to the cessation of air traffic due to the relocation of an airport. PNC and wind data were measured at one station on the airfield downwind of the runways for the prevailing wind direction for about three weeks each before and after the closure of the airport.We observed a 30 - 40 % drop in PNC after the closure of the airport regardless of the wind direction. 70 % higher PNC on average, 2.5 times higher maximum values as well as a three times higher dispersion of PNC occured with wind from the direction of the airport before the closure of the airport than afterwards. These differences are only evident during the day when air traffic is active and not during the nighttime flight restrictions. More frequent and higher concentration peaks occur in conjunction with wind from the airport before flight operations ceased.The special circumstances resulting from the relocation of the airport allow clear conclusions to be drawn about the importance of airport operations for PNC in the area of the airfield. As the study took place under Covid-19 pandemic conditions, it shows the impact of aircraft movements on PNC, but does not allow conclusions about air pollution during normal air traffic. Further studies or modelling on the spatial dispersion of airport-related air pollutants and thus on the exposure of the population living and working nearby can close the gap on health effects of air traffic.The study has been published as Fritz S., Aust S. and Sauter T. (2022): Impact of the closure of Berlin-Tegel Airport on ultrafine particle number concentrations on the airfield. Front. Environ. Sci. 10:1061584, doi: 10.3389/fenvs.2022.1061584. The study was supported by the German Federal Ministry of Education and Research (BMBF) under grant FKZ 01LP 1912B (Urban Climate under Change, Phase II, Module 3DO + M).
Effects of long-term enhanced game population density on soil physical, chemical, and microbiological properties
Authors: Inselsbacher Erich , Gerzabek Helene , Nopp-Mayr Ursula , Gerzabek Martin
Published: February 2023

Forests are critically influenced by game animals since the browsing and peeling by these animals has a detrimental effect on forests by affecting a broad range of processes in forest ecosystems. Further, plants that are browsed by herbivorous game animals show stress reactions which can lead to a change in plant species composition and in belowground interactions between roots and soil microorganisms. On the other hand, a high game population density leads to high nutrient and carbon (C) inputs via excrement and, in case of feeding, via fodder inputs. These inputs can have positive effects on plant nutrition and growth as well as soil organic C build-up. While previous studies have focused on various topics related to the effects of game animals on forest ecosystems, an overarching understanding of soil-plant-wildlife interactions and feedback reactions is still missing. In this study, we aim at tackling this short-coming and elucidating the effect of long-term enhanced game population density on soil physical, chemical, and microbial properties. The study site includes different forest types located in the vicinity of Vienna, Austria, and consists of a fenced area with high game animal population density and a directly adjacent, open forest area with lower animal density, serving as a control. Soil samples were taken from three depths (0-10 cm, 10-20 cm, 20-50 cm) from ten sub-sites differing in plant species composition and underbrush density. In the laboratory, we analyzed soil density, particle size distribution, pH, electric conductivity, total C and N, microbial biomass C and N, plant-available nutrients, and root density to study the effect of a high density of game animals (wild boars, deer) in the study area. The results gained in this study will serve as a scientific basis for a subsequent, long-term research and monitoring strategy. Here, we present results from the first sampling campaign and discuss implications of environmental impacts of wildlife animals on a larger scale.