bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical modeling of north china craton Thinning and destruction.
Authors: Zheng Ming-Jun , Lee Yuan-Hsi , Tan Eh
Published: February 2023

 The North China Craton is located on the Eurasian continental margin. Since the Mesozoic, the Izanagi and Pacific plates are subducting westward with the trench retreating eastward over time. This process is accompanied by extensive magmatism, development of rift basins, and the formation of the Japan sea. The lithosphere of the North China Craton, which is about 220 km thick, gradually becomes thinner from west to east down to around 60-80 km. Due to extensive magmatism between 140-120Ma, we believe that the North China Craton was positioned at the back-arc area of the Eurasian continental margin where the Izanagi plate currently subducts, and the trench gradually migrated eastward. We assume that the subduction event formed a large-scale high-temperature weak zone, similar to the high-temperature back-arc region mentioned in (Currie & Hyndman, 2006). By using thermo-mechanical modeling, we simulated the Craton break-up process. Following a continuous eastward extension model characterized by normal faulting and lithospheric thinning, we approximated the observed lithospheric variations. If the extension of the Japan sea is not considered, lithospheric thickness was simulated to decrease from 220 km to 60 km eastward. Within 600 km of tension, continuous lithospheric thinning will eventually lead to the formation of oceanic crust (Japan sea).        We tested the mechanism affecting lithosphere thinning and found that a large-scale initial high-temperature weak zone and a low-viscosity mantle (with a large amount of fluid participation) are the key factors for the break-up of the North China craton.
Precipitation origin in atmospheric rivers from a global perspective: first steps
Authors: Crespo-Otero Alfredo , Insua-Costa Damián , Míguez-Macho Gonzalo
Published: February 2023

Atmospheric rivers (ARs) are filaments of enhanced moisture in the atmosphere, usually located in subtropical zones and mid-latitudes over oceanic areas. These structures are able to transport huge water vapor amounts, so that when they make landfall and the water vapor is forced upwards, they often cause heavy or even extreme rainfall, thus increasing the odds of catastrophic flooding. Given their potential effects on our daily lives, a better understanding of their physical properties is therefore needed. 

One of the most studied and debated ARs properties in recent years is the origin of the moisture in them. Despite the numerous scholars dealing with this topic, moisture sources for precipitation in ARs have not yet been investigated from a global and climatological perspective.  Here we present a first attempt to fill this gap by selecting different ARs events across the globe and subsequently simulating them with the FLEXPART model, enabled to calculate Lagrangian trajectories of individual air particles. In addition, we use state-of-the-art techniques to process and bias-correct FLEXPART outputs in other to accurately estimate precipitation origins. Our preliminary results reveal that ARs can tap from multiple moisture sources and that the contributions of the latter vary widely from case to case. Therefore, we conclude that moisture uptake in ARs is more complex and varied than previously known.  
Coupling approach in shallow, unconfined aquifers in the Po Plain area: A preliminary study for future ground monitoring purposes.
Authors: Eid Celine , Benetatos Christoforos , Rocca Vera
Published: February 2023

The use of the coupling approach in analyzing the interaction between the flow field and the stress field in shallow, unconsolidated aquifers allows a better description of the involved phenomena. We perform our study on an area in the Po Plain (northern Italy) in the province of Bologna in Emilia-Romagna based on intended future studies on ground movements due to the superposition of shallow water production with deep underground gas storage.The static geological model of the alluvial sediments, locally exceeding 500 meters of thickness, is developed via a stochastic approach in order to manage the high degree of uncertainty in the system spatial continuity and heterogeneities. Corresponding water production data and piezometric measurements are collected for simulating the dynamic behavior of the shallow aquifer. The high uncertainty in water production data are managed considering a maximum and minimum scenarios on the basis of punctual well measurements and regional trend information. Correlation law between petrophysical parameters and deformation variables are derived for technical literature. The coupling technique is then applied and some sensitivity analysis are developed to assess the effects of the correlation laws. The results are finally compared with the output from the uncoupled techniques.
The role of water table depth and plant functional type in energy partitioning
Authors: Giardina Francesco , Seneviratne Sonia I. , Stocker Benjamin D. , Liu Jiangong , Gentine Pierre
Published: February 2023

Energy partitioning between surface latent (LE) and sensible (H) heat fluxes is a key factor in the development of the boundary layer and the regulation of the hydrological cycle. Climate factors and surface cover are commonly considered the major controlling effects on energy partitioning. However, the influence of other drivers such as water table depth and groundwater convergence has rarely been considered.Here, we use an extensive dataset of eddy covariance and global remote-sensing data to show that not only climate, but also water table depth and plant functional type (PFT) play an important role in energy partitioning across different biomes. Our findings illuminate the understanding of plant water stress in terrestrial ecosystems.
InBestSoil — Monetary valuation of soil ecosystem services and creation of initiatives to invest in soil health: setting a framework for the inclusion of soil health in business and the policy-making process (Horizon Europe Project)
Authors: Soto Gómez Diego , López Periago José Eugenio , Fernández Calviño David , Rodríguez Pérez Paula
Published: February 2023

InBestSoil (IBS) project has been funded under the call "Incentives and business models for soil health" from the EU Missions program (Horizon Europe) — Grant Agreement n° 1010910990. The University of Vigo leads the project within a consortium of 19 partners from 10 countries with a 48-month duration.The IBS aims to quantify the economic benefits of the different ecosystem services that healthy soils can provide and analyze the costs and benefits of the interventions to improve soil health. This economic valuation will facilitate investments in soil health and the generation of new businesses, incentives, and policies that help us to reclaim degraded soils or improve the quality of existing ones.In IBS, we analyzed nine case studies across Europe with different land uses (agricultural, forestry, urban, and mining) across four different biogeographic regions (Boreal, Continental, Atlantic and Mediterranean). These long-term experiments have been running for years into an established network of stakeholders and businesses created to exploit improved soil quality benefits. In each case study, we will assess the outcome of soil reclamation actions by examining the actual soil quality indicators and comparing them with the antecedent indicators before the restoration process. Then, we will conduct an economic valuation of the soil quality differences by considering the potential income from the enhanced ecosystem services that have proved effective in improving soil quality indicators.To develop a multi-actor approach, we will gather data and opinions from stakeholders about every relevant item in this transformation, i.e., from selecting soil indicators to creating new incentives and policies. These consultations will be done at each step of the project through a collaborative platform developed specifically for the IBS. The IBS partners come from a wide range of sectors (from universities to distribution companies of organic products), allowing us to create an extensive network of stakeholders to share information, feedback experiences, and diffusion of results.With this information, we will first try to scale up by exporting to other areas the business models that were created around our case studies. Second, we will use the information obtained through the economic valuation to develop new business models. Finally, we will try to integrate the information obtained to develop a set of incentive support systems and new policies. Acknowledgments: This study has been funded by the Horizon Europe Project InBestSoil (GA  101091099).
Interpreting extreme climate impacts from large ensemble simulations — are they unseen or unrealistic?
Authors: Kelder Timo , Marjoribanks Tim , Slater Louise , Wanders Niko , Wilby Rob , Prudhomme Christel
Published: February 2023

Large ensemble simulations may be exploited to appreciate plausible extreme climate impacts that we may not yet have seen. Such information can be vital for decision makers to anticipate otherwise unforeseen impacts. Large ensemble simulations can generate larger data samples than the observed record but biases are likely to exist, which may occasionally produce unrealistic extreme events. Interpreting simulated 'unseen' events that are more extreme than those seen in historical records is therefore crucial, but adequate evaluation is complicated by observational uncertainties and natural variability. In this talk, we introduce a three-step procedure to assess the realism of simulated extreme events based on the model properties (step 1), statistical features (step 2), and physical credibility of the extreme events (step 3). We use the global climate model EC-Earth and global hydrological model PCR-GLOBWB to demonstrate these steps for a 2000 year Amazon monthly flood ensemble. The spatial model resolution of 1x1° and daily temporal resolution is coarse, but no reason to dismiss monthly flood simulations over the Amazon a priori. We find that the simulations are statistically inconsistent with the observations, but we cannot determine whether simulations outside observed variability are inconsistent for the right physical reasons. For example, there could be legitimate discrepancies between simulations and observations resulting from infrequent temporal compounding of multiple flood peaks, rarely seen in observations. Physical credibility checks are crucial to assessing their realism and show that the unseen Amazon monthly floods were generated by an unrealistic bias correction of precipitation. Based on this case study, we discuss the takeaway challenges when evaluating extreme climate impacts from large ensemble simulations. Understanding the drivers of simulations outside observed variability helps to gain trust in unseen simulations. Uncovering the characteristics of events in the models may reveal the most important model deficiencies or improve our scientific understanding of unseen events.
On the peak metamorphic conditions of the Yuli belt, eastern Taiwan: new constraints using garnet isopleths
Authors: Lo Wen-Han , Tsai Chin-Ho , Dewangga Dominikus Deka
Published: February 2023

Two metamélange units in the Yuli belt contain high-pressure (HP) metamorphic rocks attesting to subduction zone metamorphism. These metamélange units are characterized by blocks of serpentinites, metaigneous, and metavolcaniclastic rocks in a matrix of garnet pelitic schist. Some of the blocks contain HP minerals (glaucophane, omphacite), but their peak metamorphic conditions are still poorly constrained. This presentation reports a compilation of garnet textures and compositions from these blocks and adjacent pelitic schists. Phase equilibrium modeling (Perple_X) with garnet isopleths is applied to estimate the P-T conditions quantitatively. We recognized two types of garnet compositional nature in these HP blocks. Garnet in the glaucophane schists (GlnS) displays a Mn-rich core and Fe-rich rim. By contrast, garnet in the garnet-paragonite-epidote amphibolites (GPEA) is nearly homogeneous and relatively Mg-rich. Garnet of the adjacent pelitic schists (PS) shows a similar zoning to that of the GlnS. The peak P-T conditions of these HP rocks constrained by garnet isopleths reveal a P-T range in 10–18 kbar and 500–580 ºC. The inferred P-T paths for the GlnS and PS are clockwise, whereas the one for the GPEA seems counter-clockwise. Our new P-T constraints suggest that these HP blocks and the metapelitic matrix likely formed in a paleo-subduction interface. The discrepancy in P-T data and paths among different rock types may reflect a kind of tectonic mixing.Keywords: subduction zone, subduction interface, tectonic mélange, tectonic mixing, phase equilibrium modeling, garnet chemical zoning 
Surge-tide interaction along the Italian coastline
Authors: Antonini Alessandro , Ragno Elisa , Pasquali Davide
Published: February 2023

Storm surge events are probably one of the most studied phenomena in coastal regions since they can lead to coastal flooding, environmental damage, and sometimes loss of human life. In regions of shallow water, among other localized processes, surges occurring at high astronomical tides tend to be damped while surges occurring at rising tides are amplified affecting water level extremes. This requires accounting for tide-surge interaction when defining the coastal hazards due to extreme water levels.
Cities along the Italian coast, such as Venice, Ravenna, Bari (Adriatic sea), Genova, Livorno, Napoli, and Palermo (Tyrrhenian sea), are vulnerable to coastal flooding. Hence, a thorough understanding of the interaction between water level components, i.e., storm surge and astronomical tides, is required to define a proper framework for coastal risk assessment.
Here, we analyze water level observations in several Italian coastal locations to investigate possible correlation and interaction between astronomical tide and the storm surge. Then we study the effect that such interaction has on extreme water level statistics to support the development of flood-resilient adaptation strategies.
Ozone source apportionment with a tagging approach in the LOTOS-EUROS model
Authors: Schaap Martijn , Kranenburg Richard , Thuerkow Markus , Lupascu Aura , Butler Tim
Published: February 2023

As the majority of the population is exposed to air pollutant levels above the WHO guidelines, poor air quality remains one of the key challenges to increase human wellbeing in Europe. To further improve the ambient air quality it is important to know the extent to which the different anthropogenic activities contribute to the population exposures of particulate matter, nitrogen oxides and ozone. Source attribution is a process of tracing pollution levels back to its origin. Within the LOTOS-EUROS chemistry transport model a labelling technique has been developed and applied extensively for particulate matter and nitrogen oxides. So far, ozone source apportionment was not available.The existing labelling approach was extended for ozone inspired by the implementation of the TOAST module in WRF-CHEM (Lupascu and Butler, 2019). We implemented an additional labelling family for the Ox family. For all reactions in which NO is oxidized to NO2 by a peroxide (RO2 or HO2) the NO2 produced in the Ox family receives the origin of the NO from the NOy family. By capitalizing on the existing labelling modules of LOTOS-EUROS we benefit from the more efficient implementation than simply increasing the number of tracers in the chemical mechanism.     The new implementation was applied for the year 2019 by adopting zooming approach with a European domain and a higher resolution nest across northwestern Europe. Evaluation against measurements shows that the model is well capable to reproduce the observed variability across the country. During winter time in northwestern Europe the regional background ozone levels are largely determined by influx from the hemispheric background. Regional production from road transport and other combustion sources are important from July to September, whereas increased levels during spring show considerable contributions from ozone formed in southern Europe. To investigate in how far two modelling systems agree or deviate from each other in terms of source apportionment, simulations with LOTOS-EUROS and WRF-CHEM with a consistent model setup and labelling strategy were performed. The results of this analysis will also be shown at the meeting. Lupaşcu, A. and Butler, T.: Source attribution of European surface O3 using a tagged O3 mechanism, Atmos. Chem. Phys., 19, 14535–14558, https://doi.org/10.5194/acp-19-14535-2019, 2019
Geophysical survey of near-surface aquifers for the goals of Managed Aquifer Recharge in a settlement of the Danube-Tisza Interfluve, Hungary
Authors: Oláh Soma , Szijártó Márk , Visnovitz Ferenc , Mádl-Szőnyi Judit
Published: February 2023

For recent decades, the groundwater level has been decreasing in the area of the Danube-Tisza Interfluve, Hungary, mainly due to climate change. The average depth of water table is between 5-7 m in the elevated Interfluve area. The shallow eolian and fluvial aquifers of the region can be used to store water between the surface and water table for later extraction or for ecological benefit. Therefore, Managed Aquifer Recharge (MAR) systems could play an essential role in improving the stored water and the water balance in the Danube-Tisza Interfluve.The aim of the research was to carry out a geophysical survey and a complex data processing in order to analyse the characteristics of near-surface sediments of Kerekegyháza town (Danube-Tisza Interfluve, Hungary) for MAR implementation. For a detailed understanding of the shallow geological environment in Kerekegyháza, we used three main data systems and previous interpretations. Stratigraphic information was collected and examined from (1) hydrogeological reports. In addition, (2) archived vertical electric sounding (VES) measurements were reprocessed. Furthermore, (3) two-dimensional electric resistivity tomography (ERT) was performed. Summarizing the lithological and electric resistivity data, 4 geological sections and a complex 3D data system were compiled.Interpreting the preliminary information, a simplified three-layered (uncovered aquifer – aquitard – covered aquifer) geological model was set up in the pilot area. Based on the stratigraphic information and the electric resistivity values, the geological setting is more heterogeneous than the simplified model. Hence the determined layers are not horizontally continuous, except for the uncovered dry sand or quicksand aquifer with 0-3 m thickness. Below that, presumably clay lenses cause rapid lateral variations in the grain size and the resistivity. However, the correspondence between the electrical and lithological divisions is not evident due to the different resolutions of the applied methods. The ERT results suggest that the pattern of heterogeneity shows spatial variation, which requires further research to explain the exact geological causes. The most significant reservoir in the area of the town is the covered sand formation with ~15 m thickness, detected by all applied methods.The results can provide background for planning the appropriate technique of Managed Aquifer Recharge in the town of Kerekegyháza, mitigating further groundwater subsidence. In addition, its application for further cities in the elevated region of the Danube-Tisza Interfluve can contribute to more sustainable management with available water resources.The research was funded by the National Multidisciplinary Laboratory for Climate Change, RRF-2.3.1-21-2022-00014 project.
Net ecosystem carbon balance, emissions of methane and nitrous oxide and water quality in the first four years of rewetting a cultivated peat soil site for paludiculture
Authors: Lång Kristiina , Kekkonen Hanna , Honkanen Henri , Heikkinen Jaakko , Saarnio Sanna , Larmola Tuula
Published: February 2023

Cultivated peatlands are a major source of greenhouse gas (GHG) emissions and water pollution in northern Europe, and their future management is a key issue on the path to carbon neutral societies. Conventional cultivation requires drainage, and above the drainage depth all peat is prone to decomposition with the implication that these soils have the highest emission rates per area compared to any other land use. Paludiculture is a management option in which wet-tolerant crops are produced with raised ground water levels. It is thus a GHG mitigation method that allows for slowing down peat decomposition in drained peatlands while still maintaining agricultural income for the landowner. There are tradeoffs to consider when implementing paludiculture: 1) methane emissions rise with the switch of aerobic to anaerobic decomposition, 2) slowing down decomposition reduces nutrient mineralisation from the peat and compromises productivity and 3) harvesting reduces the potential to sequester carbon to the ecosystem compared to natural wetlands. 

We experimented paludiculture at a highly degraded peat site in southern Finland with plots of willow, forage, and mixed vegetation (set-aside). We recorded the yields, emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) and auxiliary environmental data for four years, as well as nutrient content of the soil water for two years. We will present the results of these measurements, including estimates on the net ecosystem carbon balance of each crop based on empiric models.  

Raising the ground water level to the desired depth (-20 cm) turned out to be challenging. The mean annual ground water table levels during the four study years were about 80, 40, 40 and 30 cm (the measurements of the last year are still ongoing). The preliminary results suggest that even a slight raise of the ground water level was able to slow down CO2 emissions from soil respiration, while an increase in CH4 emission partly counteracted this benefit especially when the ground water level was above 30 cm. Nitrous oxide emissions were extremely high after the initial disturbance of the site but remained at a relatively low level after that. The results will be compared to an adjacent site with an annual crop, and paludiculture as a mitigation measure discussed.  
Environmental controls on the distribution of life in shallow seas on the early Earth in the 3.33 Ga Josefsdal Chert, Barberton Greenstone Belt
Authors: Westall Frances , Bréhéret Jean , Hickman-Lewis Keyron , Campbell Kathleen , Giudo Diego , Foucher Frédéric , Cavalazzi Barbara
Published: February 2023

The 3.33 Ga Josefsdal Chert in the Barberton Greenstone Belt, South Africa, records a sequence of sediments deposited under shifting energy conditions in a nearshore paleoenvironment (1, 2). At the base, volcanoclastic sediments were deposited under somewhat dynamic conditions on top of pillow basalt and hydrothermal chert. They grade gradually upwards into alternating deposits of chemical silica and very fine scale microbialites tabular phototrophic mats) formed under very quiet conditions frequently interrupted by storm currents, which then transitioned sharply into thinly bedded tuffs with much hydrothermal activity at the base. Growth faults permitted thick sequences of very shallow sediments to accumulate. While the REE data show the global, background Eu signature of hydrothermal influence throughout, local Sm/Yb:Eu/Sm ratios document local hydrothermal hot spots. Fluvial inflow is documented by flat REE patterns in the middle to upper sequences (2).Within this environmental background, microbialites abound, their nature (phototrophic/chemotrophic), distribution and preservation being influenced by environmental factors, such as water depth (phototrophy), sedimentation flux, and hydrothermal vents and activity. Phototrophic activity was abundant during the middle, volcanically quiet period and was present also during the lower and upper volcanoclastic depositional periods, with biofilms and mats forming on the tops of individual fining upwards layers (3,4). Chemotrophic colonies were abundant in the vicinity of hydrothermal vents (5). Amost instantaneous silicification of both sediments and the microbialites resulted in excellent preservation, although the organo-geochemical signatures are heavily diluted (SiO2 contents ranging from ~ 90-99.9%). Biogenicity of the different microbialites was evaluated on the basis of their morphology, interactions with the immediately surrounding sediment and environmental conditions (e.g.current flow), organic carbon and δ13C compositions, as well as their transition element compositions and the presence of minerals precipitated as by-products of microbial metabolism (e.g. aragonite, sulphate). Periodic exposure of some of the phototrophic biofilms, as indicated by desiccation and entrapped layers of pseudomorphed evaporite minerals (aragonite, calcite, gypsum, and halite)(3,4), as well as desiccation texture on certain bedding planes, indicates a littoral, on shore environment of formation.(1) Westall, F. et al., 2015, Geology, 43, 615; (2) Westall, F., Bréhéret, J. et al. in prep.; (3) Westall, F. et al., 2006, Phil. Trans. Roy. Soc. Lond. B., 361, 1857; (4) Westall, F. et al., 2011, Earth Planet. Sci. Lett., 310, 468; (5) Hickman-Lewis, K., et al. 2020, Sci Rep 10, 4965.
Creating School Seismology Labs For the Development of Students’
Authors: Simionescu Cristina , Tataru Dragos , Nastase Eduard , Necula Eduard , Vanciu Rau Adina , Zaharia Bogdan
Published: February 2023

Educational seismology projects all over the world allow schools to detect signals from large earthquakes happening anywhere in the world. It starts from the natural interest and fascination for the destructive power of earthquakes. Still, the experiment quickly became much more, from simple information to exposing fundamental concepts tested by practical experiments. In the framework of the Romanian Educational Seismic Network, classroom activities that enable students to learn about some basic science concepts using seismology and earthquakes as a unifying theme have been developed in the last decade. Students are guided to use concepts such as energy transfer, wave properties, and resonance to understand elementary models of earthquakes' causes and effects. From 2022, a new Erasmus Project adds one more piece to the framework, together with a truly regional approach - SEISMOLAB - Creating School Seismology Labs For the Development of Students’. One of the aims of the project is to bring together seismologists, pedagogues, curriculum developers, local authorities, advanced educational developers, and schools to join forces during the implementation and co-design, develop and validate an innovative professional development program for supporting the in-service training of teachers on topics related, but not limited to seismology education. Thus, apart from Seismology, participants will be familiarised with the open schooling approach that provides a powerful framework to engage, discuss and explore how schools can facilitate open, more effective, and efficient co-design, co-creation, and use of educational content tools and services for personalised science learning and teaching and citizens science.In Romania, the project will be piloted in ten secondary and high schools where SEISMO-labs will be developed based on a framework for organising School Development Labs of Students’ Competences and a set of educational scenarios (SEISMO-Labs demonstrators). A SEISMO-Lab Toolkit and a teacher training program will prepare teachers to implement SEISMO-Labs in their schools, receiving training on the approach and the pedagogical methodologies. An evaluation methodology will be designed for mapping and monitoring the impact and effectiveness, both quantitatively and qualitatively, at the student, teacher, and school/institution level of the SEISMO-Labs.ACKNOWLEDGEMENTSThis work was done in the framework of the project “Seismo-Lab” which has been funded with support from the European Commission under the Erasmus+ programme (Grant agreement number 2021-1-EL01-KA220-SCH-000032578).
Neutral and stratified turbulent boundary layer flow over low mountains
Authors: Lott Francois , Pauget Lucile , Beljaars Anton
Published: February 2023

A uniform approximation of flow over gentle hills with a turbulent closure based on mixing length theory is derived. It permits to  describe the transition from neutral to stratified flow in the production of mountain drag. Our results corroborate previous studies showing that the transition from the form drag associated to the mountain induced changes in boundary layer friction  to the mountain gravity waves drag can be captured by theory. We also confirm that the first is associated with downstream sheltering with relative acceleration at the hill top, the second with upstream blocking with strong downslope winds.  We also show that the downslope winds penetrate well into the inner layer. The theory show that the altitude at which the incident flow need to be taken to calculate the drag is related to the inner layer depth at which dissipative effects equilibrate disturbance advection. We also show that the parameter that capture the transition, which in our case is a Richardson number, is directly related to the altitude of the turning levels of the gravity waves with respect to the mountain length. Our uniform solutions are also used to describe the wave field aloft and the distribution of the Reynolds stress in the vertical. Some directions to combine neutral and stratified effects in the parameterization of subgrid scale orographies in large scale models are given.
AI based 1D and 3D P- and S-Wave Velocity Models for the Alpine Mountain Chain from Local Earthquake Data
Authors: Braszus Benedikt , Rietbrock Andreas , Haberland Christian , Ryberg Trond
Published: February 2023

The increase in seismic data availability as well as the improvement of automated picking algorithms allows us to reassess the seismicity and velocity structure in many regions around the globe with higher accuracy. Using the seismic recordings from a total of more than 1100 stations of the AlpArray Seismic Network and other permanent and temporary stations within the area we work towards a comprehensive 3D P- and S-wave crustal velocity model for the European Alpine region using Local Earthquake Tomography. Phase arrival times of local seismicity are determined by the widely used deep neural network PhaseNet.We present first a P- & S-wave minimum 1D model of the Greater Alpine region computed with the established linearized inversion algorithm VELEST and compare it to our new 1D model using a bayesian Markov chain Monte Carlo (McMC) algorithm exploring a broader model space. Pg and Pn phase arrivals in the epicentral distance ranges from 0-130km and 300-600km, respectively, are included while picks within the triplication zone from 130-300km are not considered due to difficult phase identification. Both models match within the error margin of the McMC result, while the discrepancy is largest in the lower crust where the resolution decreases due to the chosen epicentral distance ranges. With our minimum 1D model as starting model we compute a 3D P-wave model using the SIMULPS code. As the remaining residual distributions of the 1D and 3D model show, the removal of outliers in the pick catalog is more accurate when based on the 3D residuals due to insufficient incorporation of velocity variations along epicentral distance and backazimuth in the 1D model. The most prominent first order structures of the 3D model are in agreement with previous local studies of the area and the model already can be used to consistently improve crustal correction terms on an orogenic scale for teleseimic tomographies and thus sharpen the seismic image of the upper mantle. Furthermore, it will allow to the associate the phases Pg, Pmp & Pn to picked onset times in the crustal triplication zone more accurately. Due to their ray paths these picks are of special importance to the resolution in the lower crust and will contribute significantly to the final 3D P- and S-wave model. Absolute velocities along the Moho interface are higher than in previous studies and therefore in better accordance with values expected from petrology.  
Characterization and Monitoring of the Gunnuhver geothermal site using electrical methods
Authors: Vanhooren Lore , Fontaine Olivier , Caudron Corentin , Vrancken Elien , Dekoninck Warre , De Lathauwer Hanne , Hermans Thomas
Published: February 2023

Volcanic Hydrothermal systems (VHS) are three-phase reservoirs between the magma chamber and the earth’s surface, they are present in most volcanoes on Earth but the dynamical behavior is currently poorly known. As fluid circulation gives rise to a range of geophysical and hydrothermal signals, it complicates the detection of pre-eruptive signals, hence certain volcanoes remain on alert for significant amounts of time without erupting. Moreover, VHS lie at the basis of phreatic or hydrothermal eruptions, which can cause significant casualties. Given these safety concerns it is thus paramount that we gain a better understanding of the dynamics of VHS.Traditionally seismometers are used to monitor VHS but the high level of background noise complicates the application of standard processing techniques. Here we apply geo-electric methods for characterization and monitoring. Electrical Resistivity Tomography (ERT) and Induced Polarization (IP) provide a relatively high resolution image of the subsurface electrical properties. The main dynamic processes occurring in VHS are temperature changes, variations in saturation and mineral precipitation, all of which influence the electrical signal making ERT/IP a suitable method to monitor this system. Similarly, the spontaneous potential signal (SP) is influenced by fluid flow and diffusion/conduction processes and should therefore bring complementary information to ERT/IP.  In this project the Gunnuhver geothermal area in Iceland is monitored on a daily basis since October 2022. Prior to the monitoring campaign a field characterization was executed where 5 profiles were measured using ERT/IP and SP. Due to the proximity to the ocean, the groundwater in this area is saline which complicates the IP data acquisition, as saline environments have a low ability to store electrical charge. Hence, in the characterization phase we attempted to find the most suitable method for acquiring an IP signal in this high-temperature, saline setting. The static ERT profiles show a high spatial variability in the area, where the alteration zone, characterized by very low resistivity, is clearly distinguishable from the more resistive basalt. Adjacent to the geo-electrical methods the characterization and monitoring also include seismicity, fiber-grating, CO2 measurements and shallow soil-moisture and -temperature measurements.By developing a novel time-lapse inversion approach, where the auxiliary data helps to constrain the interpretation of the ERT/IP profiles, we are able to get new insights into the inner workings of Volcanic Hydrothermal Systems.
A new python code to invert 36Cl cosmogenic nuclide dataset on normal fault bedrock scarps: comparison with previous published codes and results on the accuracy of the retrieved seismic history of two normal fault systems in Central Apennines
Authors: Llinares Maureen , Benedetti Lucilla , Gassier Ghislain , Viseur Sophie
Published: February 2023

Measuring 36Cl cosmogenic nuclides on exposed bedrock fault scarps has now been used in several places in the Mediterranean to retrieve ages of the fault seismic history (e.g. Mechernich et al. 2022, Iezzi et al. 2021 and Cowie et al. 2017).In Central Apennines, around the Fucino basin, at least 15 36Cl sampling sites were analyzed in previous studies to interpret the 36Cl data as seismic history or slip-rates. Several codes (e.g., Beck et al. 2018, Shlagenhauf et al. 2010) were used as a basis for solving 36Cl production equations to calculate the 36Cl concentration resulting from bedrock scarp exhumation history. Some codes included an MCMC routine to retrieve the seismic histories the closest to the dataset. The main differences between the various codes lie in: 1-the fault history prior to exhumation, 2-the parameters previous authors decided to inverse (as an example, mean density of the colluvium is inversed in Beck et al. 2018 but not in Tesson et al. 2019) and 3-the a priori distribution of those parameters (for instance, the time between two earthquakes follows an inverse gaussian distribution for Beck et al. 2018 but a uniform distribution for Tesson et al. 2019). I have compared the various codes and run them on the same dataset (one site at Campo Felice, one site at Roccapreturo and one site at Magnola) and found that retrieved seismic histories are similar, although the estimation of uncertainties differs.Moreover, all previous cited codes run under Matlab or Fortran. Fortran codes have the advantage of fast computing time but could be cumbersomeI here propose a new code, adapted from Tesson et al. 2019, in the more accessible and widely used Python language. The inferred pre-exposure is also inversed and is a function of the height of the fault cumulative escarpment. The parameters considered are the number of events, ages of event, the associated slips, the long term slip rate, the quiescence and the pre-exposure and their optimal evaluation is done with a MCMC algorithm provided by Numpyro (Du Phan et al. 2019).Using this new code, we have reanalyzed the 15 36Cl sites around the Fucino and, through a gaussian mixture algorithm, checked the hypothesis of common periods of activity throughout all the Fucino basin. 
The influence of radiosonde observations on the sharpness and altitude of the tropopause
Authors: Krüger Konstantin , Schäfler Andreas , Craig George , Weissmann Martin
Published: February 2023

The shape, sharpness and altitude of the extratropical tropopause (TP) is strongly linked to the position and the strength of the subtropical and polar jet streams that determine the weather in the midlatitudes. However, current numerical weather prediction models fail to correctly represent the sharpness of the TP (i.e., the gradients of wind and temperature). In this study, we address the question if and how the assimilation of radiosonde observations influences the TP representation and whether it acts to sharpen or smooth near near-tropopause gradient.We investigate the influence by comparing temperature, Brunt-Väisälä frequency (N²) and wind profiles of the observations (y), the model background (xb) and the analysis (xa) in tropopause-relative coordinates.In total, we analyse more than 9000 radiosondes that were assimilated by the European Centre for Medium-Range Weather Forecast’s Integrated Forecast System (ECMWF IFS) over Canada, the Northern Atlantic and Europe during a one-month period in fall 2016. To test whether the diagnosed influence is caused by the assimilated radiosondes, we conducted a data denial experiment that excluded 500 radiosondes that were launched in the framework of the North Atlantic Waveguide and Downstream EXperiment (NAWDEX) field campaign. In observation space, we investigate the departures (i.e., the differences between y, xb and xa) in the control run (CTR) with all radiosondes considered and the denial run (DEN) without the NAWDEX radiosondes.The observed minimum temperature at the TP is overestimated in the background forecast (warm bias, ~1 K). Above, in a layer 0.5-2 km, the temperature is underestimated (~0.5 K). Consequently, the sharpness of the TP which is diagnosed by the maximum of N² is also underestimated. We show that data assimilation is able to improve the temperature and to slightly strengthen the TP in the analysis, particularly in situations where the observed and model TP altitude fairly agree. In the data denial experiment we show that this influence exists in the CTR, but not in the DEN run, and thus can be attributed to the assimilation of the radiosonde data.Regarding wind, we find an underestimation of the maximum wind at and below the TP (0.5-1 m s-1) and demonstrate that the assimilation of radiosonde winds is able to improve the wind profile across the TP. The bias and the positive influence are found to be stronger in situation of strong wind, i.e., the jet stream.Although data assimilation is able to improve wind and temperature gradients across the tropopause by pulling the background closer to the observations, the individual analysis profiles still underestimate the sharpness of the tropopause. The misrepresented TP in models may impact the quality of weather and climate projections.
The metasomatic processes and thermal condition of lithosphere mantle under the center of Siberian craton: evidences of pyroxenite xenoliths from Mir kimberlite pipe
Authors: Kalashnikova Tatiana , Kostrovitsky Sergei
Published: February 2023

The study of mantle xenoliths from kimberlite pipes allows to establish the composition, evolution processes and thermal condition of the lithospheric mantle under ancient cratons. The Mirny kimberlite field belongs to the diamond-bearing kimberlite fields in the center of the Siberian craton. The collection of mantle xenoliths from the Mir pipe (57 samples) was investigated by authors. Four main petrographic groups were identified: peridotites (Grt lherzolites), Grt websterites, Grt clinopyroxenites and eclogites. The pyroxenite xenoliths attract the special attention.   Garnets from lherzolites and websterites are also characterized by a relatively high Mg# content (75–83) and low TiO2 contents (up to 0.2 wt %). Eclogites are characterized by high-calcium (3.78 - 9.46 wt.%) and high-iron (7.77 - 17.20 wt.%) composition of garnet getting into the ​​wehrlite paragenesis area. Thus, the lithospheric mantle under the Mirny kimberlite field differs from the lithospheric mantle under other diamondiferous fields (for example, Udachnaya kimberlite pipe). The Mirny mantle xenoliths are characterized by the pyroxenites widespread development (up to 50%), the low-Ti composition and deformed lherzolites absence.In addition, websterites and lherzolites show a wide range of crystallization parameters (600 - 1200°C; 2 - 6 GPa) probably due to their gradual cooling after magmatic crystallization and the exsolution structures formation. Clinopyroxenites are characterized by narrow variations in the P-T crystallization parameters (812 - 960°C; 3-4 GPa) indicated their later crystallization from asthenospheric melts. Eclogites are characterized by relatively low calculated temperature parameters (720–840°C; 2.2–3.7 GPa) confirming their origin in subduction zones at shallow depths. The sporadic calculated values for websterites and clinopyroxenites are locating within the diamond stability area. The use of the Opx - thermobarometer (in samples founding Opx) revealed 2 trends in the crystallization of orthopyroxene. Crystallization of individual Opx grains in websterites occurred earlier than Cpx with higher P-T parameters - higher by ~100С and ~0.5 Ha. The second trend (pressure reduction with a slight decrease in temperature) notes the formation of Opx decay structures in an initially homogeneous crystal of monoclinic pyroxene. Minerals from pyroxenites demonstrate a wide development of melting processes in the lithospheric mantle in the south of the Siberian craton Craton and the formation of megacrystalline pyroxene cumulates. The origin of eclogites is assumed from subducted oceanic crust marking the subduction component in the process of formation of the lithospheric mantle.The research was supported by Russian Science Foundation grant № 22-77-10073.
Altitude extension of NCAR-TIEGCM (TIEGCM‑X) and evaluation
Authors: Cai Yihui , Yue Xinan , Wang Wenbin , Zhang Shun‑Rong , Liu Huixin , Lin Dong , Wu Haonan , Yue Jia , Bruinsma Sean L. , Ding Feng , Ren Zhipeng , Liu Libo
Published: February 2023

The upper boundary height of the traditional community general circulation model of the ionosphere‑thermosphere system is too low to be applied to the topside ionosphere/thermosphere study. In this study, the National Center for Atmospheric Research Thermosphere‑Ionosphere‑Electrodynamics General Circulation Model (NCAR‑TIEGCM) was successfully extended upward by four scale heights from 400–600 km to 700–1200 km depending on solar activity, named TIEGCM‑X. The topside ionosphere and thermosphere simulated by TIEGCM‑X agree well with the observations derived from a topside sounder and satellite drag data. In addition, the neutral density, temperature, and electron density simulated by TIEGCM‑X are morphologically consistent with the NCAR‑TIEGCM simulations before extension. The latitude‑altitude distribution of the equatorial ionization anomaly derived from TIEGCM‑X is more reasonable. During geomagnetic storm events, the thermospheric responses of TIEGCM‑X are similar to TIEGCM. However, the ionospheric storm effects in TIEGCM-X are stronger than those in TIEGCM and are even opposites at some middle and low latitudes due to the presence of more closed magnetic field lines. DMSP observations prove that the ionospheric storm effect of TIEGCM-X is more reasonable. The well‑validated TIEGCM‑X has significant potential applications in ionospheric/thermospheric studies, such as the responses to storms, low‑latitude dynamics, and data assimilation.
Growth and chain formations of diatoms (Pseudo-nitzschia) under different turbulent conditions: a laboratory analysis
Authors: Bampouris Vasileios , Houliez Emilie , Schmitt Francois G. , Crouvoiser Muriel , Kormas Kostas , Christaki Urania
Published: February 2023

Diatoms have high productivity and are highly influenced by turbulent conditions. We consider here diatoms of the species Pseudo-nitzschia,  which are chain forming. The objective of this work was to show how the turbulent environment affects the growth and the chain forming of these species. For this, cultures of the species Pseudo-nitzschia multiseries and Pseudo-nitzschia fraudulenta were performed in the laboratory and submitted to stationary turbulent conditions, using the Agiturb system developed in the LOG at Wimereux (Le Quiniou et al. 2022). In the Agiturb system, the turbulent flow is produced using four contra-rotating agitators that are placed under a cubic tank, generating a statistically stationary, spatially inhomogeneous flow with compression and stretching. The injection of the energy in the flow is produced by 4 stirring bars activated by 4 magnetic stirrers situated at symmetric positions. The cubic tank is almost half-full with 15 liters of sea water. For each experiment, the magnitude of the rotation rate of each agitator was identical, with two agitators rotating clockwise and two anti-clockwise, the same directions being along the diagonal. Different values of the rotation rate were chosen to reach different turbulence levels, characterized by the microscale Reynolds number Rλ going from 130 to 360. These Reynolds numbers correspond to typical values found in the ocean, from the epicontinental zone, to coastal, surf zones and even storm conditions. In the experiments, all the other parameters that affect the diatoms’ proliferation were kept the same. Formation and growth of the chains were assessed through microscopy.  P. fraudulenta displayed higher growth than P. multiseries in all turbulence levels except from the control condition (Rλ=0) where the growth was approximately the same. The level of turbulence that was more beneficial for the growth of P. multiseries was the agitated (Rλ= 240) whereas for P. fraudulenta it was for a smaller Reynolds number (Rλ = 160). The chain length were also considered in relation with turbulence level, by considering the probability density of single chains, small chains (2 or 3 cells) and long chains (more than 4 cells). The result was that the predominant form of the cells for both species was the single cells. However, P. multiseries presented higher variations in chain forming throughout the whole experiment than P. fraudulenta. Within this approach, the optimal turbulence level, for growth as well as chain formation, can be assessed for each phytoplankton species.