bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal Dynamics of Dissolved Organic Carbon at the Outlet of a Rewetted Coastal Peatland
Authors: Meidani Hadi , Janssen Manon
Published: March 2024

Peatlands have a major role in the global carbon cycle. While the gaseous export of carbon from peatlands has already been well-recognized, the dissolved organic carbon (DOC) fraction has not been equally noticed. Despite covering a small area (less than 3%), peatlands contribute from 12% to 20% of the DOC being released to oceans. The DOC dynamics in streams draining peatlands are highly variable, both on seasonal and event scales, and the corresponding drivers are still under discussion, particularly differing between disturbed and pristine peatlands. The objective of this study is to determine the DOC dynamics at the outlet of a rewetted coastal peatland and assess the effects of discharge and salinity. The study area is the nature reserve “Heiligensee and Hütelmoor” on the German Baltic Sea coast with an area of 350 ha. Here, high-frequency time series of discharge and DOC concentrations (complemented with regular samplings) are measured at the drainage/ditch system outlet, and consequently, the DOC export is calculated. According to the results, DOC concentrations demonstrate a seasonal trend and seem to be diluted during higher discharges by rainfall. However, they show no evident correlation with salinity. Moreover, the high‑frequency DOC concentrations, although available only for a limited period, indicate high variabilities following rainfall/discharge events. The discharge exhibits seasonal variabilities with an increase throughout winter, and then, a continuous decrease, and is highly responsive to rainfall events. The DOC exports are strongly linked with the discharge and thus show a similar pattern with the highest values in winter and spring. Our results highlight the necessity of high-frequency fluvial DOC monitoring with respect to extreme flow events in rewetted peatlands and a deeper investigation of the hydroclimatological controls through time-series/statistical analyses. This could provide valuable insights into mitigating excessive DOC export from rewetted peatlands.
Real-time monitoring of dynamic isomer populations with CI-SLIM IMS-MS
Authors: Riva Matthieu , Gerber Sebastian , Claflin Megan , Mettke Peter , Frauenheim Molly , Rice Rebecca , Gold Avram , Surratt Jason , Yatsyna Vasyl , Graf Stephan , Canagaratna Manjula , Herrmann Hartmut , Rohner Urs , Kamrath Michael , Lopez-Hilfiker Felipe
Published: March 2024

Ion mobility spectrometry (IMS) using Structures for Lossless Ion Manipulations (SLIM) is an emerging powerful tool for rapid isomer separations. This technology offers high mobility resolution due to prolonged ion mobility path lengths that are achieved on a small form factor separation device. In this work, we interface SLIM IMS separation with a chemical ionization source, which allows one to sample from the gas- and particle-phases directly. As such, one can monitor dynamic isomer populations in ambient air in real-time without prior sample preparation. This technology opens the door to new possibilities in atmospheric chemistry where isomer distribution is expected to play a key role in gas phase processes and in the formation of organic aerosols.                  The CI-IMS-TOF instrument built by TOFWERK produces ions via a two-step chemical ionization process, which involves 1) producing reagent ions and 2) ionizing neutral analyte molecules via the reagent ions through either charge transfer or adduct formation. Once generated, these secondary ions travel into the SLIM IMS region, where a series of DC- and AC-electrodes on printed circuit boards create a traveling wave driving force. As the ions travel through the helium buffer gas, they separate based on their rotationally averaged collision cross-sections.In the present work, various experiments were performed using an aerosol flow tube reactor and an atmospheric simulation chamber to recreate atmospheric conditions. Gas-phase oxidation of isoprene was used to explore the capabilities of the CI-SLIM IMS-MS under atmospheric relevant conditions. Firstly, the most important oxidation products produced from the OH-oxidation of isoprene were used including methacrolein, methyl vinyl ketone, isoprene epoxy diols (IEPOX), isoprene hydroxy hydroperoxide (1,2 and 4,3-ISOPOOH), and other C5H10O3 reactive uptake products as a single component or as a mixture to first evaluate the capabilities of the CI-SLIM IMS-MS at resolving the different isomers. Secondly, the reactive uptake of IEPOX onto acidic particles and OH-initiated oxidation (low and high NO regimes) of isoprene were studied to characterize the dynamic of the isomers generated within the simulation chamber under various environmental conditions. Results will be presented to demonstrate the capabilities of the newly developed CI-SLIM IMS-MS at resolving isomers in real time.
Use of high-time resolution roadside measurements to inform NOx emission ratios 
Authors: Williams Carys , Drysdale Dr Will , Cliff Dr Samuel , Moller Dr Sarah , Lee Prof James
Published: March 2024

As air quality targets become more stringent, a better understanding of urban air pollution sources continues to be important for the development of targeted and effective policy.  Ambient measurements of the enhancement of NOx and CO2 concentrations above background can be linked to direct emissions via the calculation of emission ratios (ΔNOx/ΔCO2), which in turn provide insight into emission sources. In this work, we use a regression analysis method to quantify emission ratios from high time resolution (1 second) roadside measurements of NOx and CO2 taken in two major UK cities, London and Manchester. Calculated emission ratios allow us to gain a greater understanding of the effect of factors such as fleet composition and vehicle operating conditions on NOx emissions, along the roads measured. Additionally, a comparison of emission ratios across the two cities allows for an interesting discussion on the differences in traffic behaviour and effectiveness of local traffic-related policy (e.g. low emission zones). Analysis of long-term measurements of NOx and CO2 at the Marylebone Road site demonstrate the effect of changes in vehicle technology and the effect of the ULEZ. This work also aims to highlight the benefit of long-term high time resolution measurements on a local level to develop an advanced understanding of local traffic-related NOx emission characteristics.
Miocene to Quaternary Seismic Stratigraphy and Tectonic Evolution of the Marine Area Between Çandarlı Bay and Lesbos Basin, Northeastern Aegean Sea
Authors: Elitez İrem , İslam Tuba , Gültekin Derya İpek , Yaltırak Cenk
Published: March 2024

This study focuses on the marine area located between Çandarlı Bay and Lesbos Basin in the Northeastern Aegean Sea. The high quality multibeam bathymetry data, their processing and interpretation with the onshore structures and an integrated interpretation with seismic reflection profiles allowed to map the offshore active faults, to prepare the seismic stratigraphy and to evaluate the tectonic evolution of the marine area between Çandarlı Bay and Lesbos Basin. In addition, thickness maps were generated from seismic reflection profiles and seismic stratigraphic units were correlated with the Foça-1 well to reveal the characteristics of the deposited strata in this region. The seismic stratigraphic units were also compared with onshore geological units.Five major seismic stratigraphic units were identified and all of which are compatible with each other from the Çandarlı Bay to the Gulf of Izmir. The findings suggest continuous sedimentation from the Burdigalian (Lower Miocene) to the present day. A predominantly volcaniclastic sequence deposited in the Burdigalian-Serravalian period rests on basement rocks. This unit is overlain by Tortonian clastics and carbonates interbedded with volcanic rocks. Tortonian sediments are followed by about 300-500 m thick clastics and anhydrites, which were deposited in an environment corresponding to the Messinian salinity crisis in the Mediterranean Sea. The post-Messinian unit is of Pliocene age and starts with upper Miocene limestones at the base and transitioning upwards into clastic rocks. The stratigraphy concludes in the upper part with a Quaternary unit, which is mainly composed of fine-grained clastics and has been influenced by sea-level changes.The study area is dominated by both NW-SE and NNW-SSE-striking normal faults and two distinct tectonic phases have been identified. The first phase spans from the Miocene to the end of the upper Miocene and is characterized as a supra-detachment basin associated with the development of core complexes in the region. These faults do not extend to the surface in seismic sections and are indicative of an early-stage tectonic activity. The homogeneity of the sediment thickness suggests a slowdown in tectonic activity during the Tortonian-Messinian period. In the Plio-Quaternary period, the sediment thicknesses indicate uplift in the surrounding region. Additionally, the bathymetric traces of faults shaping the Lesbos Basin to the west of Çandarlı Bay indicate the presence of a new tectonic system.
U-Th dating of gypsum: methodology and reference materials
Authors: Wang Xuefeng , Wang Lisheng , Ma Zhibang , Duan Wuhui , Xiao Jule
Published: March 2024

Gypsum is a common evaporate mineral in a wide variety of geological settings, especially in arid and semi-arid areas. It often precipitated from the natural brine systems with trace amounts of U and almost no Th, rendering it a potentially valuable U-Th geochronometer. However, U-Th dating of gypsum is often challenging, such as how to quickly and completely digest gypsum into solution, and avoid the re-crystallization of gypsum particles during the digestion and chromatography process. Here we present a rapid and practical method for high-precision U-Th dating of gypsum using the (NH4)2CO3 exchange reaction and double-spike method by MC-ICPMS. Our developed protocol addresses these conventional challenges by using the chemical reaction between calcium sulfate and carbonate, resulting in the (NH4)2SO4 solution and CaCO3 precipitate. Then the CaCO3 could be easily digested by diluted acid. With the solid-liquid separation, Ca2+ and SO42- ions are also effectively separated, minimizing the recrystallization of gypsum. The (NH4)2CO3 median, the gypsum/carbonate molar ratio of 1: 4, and the exchange reaction duration of 1.5 ~ 2 hours are suggested in this protocol. Since there is no gypsum U-Th dating reference materials to validate the accuracy of different approaches and ensure methods are repeatable across laboratories. We also prepared and characterized two natural gypsum U-Th dating reference materials (PXCG-1, PXCG-2) from PiXiao Cave, southwest China. Data from three different laboratories exhibit good agreement with both 238U content, δ234U, 230Th/238U activity ratio, and the 230Th ages. The 230Th ages of PXCG-1, PXCG-2 RMs proposed are 66.97 ± 0.31 ka, 260.82 ± 3.39 ka, respectively.
Pyrite-based trace element fingerprints for methane and oil seepage
Authors: Smrzka Daniel , Lin Zhiyong , Monien Patrick , Bach Wolfgang , Peckmann Jörn , Bohrmann Gerhard
Published: March 2024

Pyrite forms at marine hydrocarbon seeps as the result of the microbial oxidation of methane, organic matter, and crude oil coupled to sulphate reduction. Redox sensitive and nutrient trace elements in pyrite may hold valuable information on present and past seepage events, the evolution of fluid composition, as well as the presence of heavy hydrocarbon compounds from crude oil. This study uses the trace element compositions of pyrite that formed at methane seeps and crude oil-dominated seeps to constrain element mobilities during the sulphate reduction processes, and to which degree specific trace elements are captured by pyrite. Pyrite forming at oil seeps shows high Mn/Fe ratios and high Mo content compared to pyrite from methane seeps. These patterns suggest either more intense or persistent sulphidic conditions, or an intensified manganese (oxy)hydroxide shuttle process at oil seeps. Copper and Zn are enriched in oil seepage-derived pyrite while Ni and V enrichment is less pronounced, suggesting either a selective uptake of specific elements by pyrite, or varying trace element compositions of organic compounds oxidized via microbial reduction.   
The multi-scale rarity matrix – a comprehensive tool to analyze the space-time severity of meteorological drought, with application to France
Authors: Blanchet Juliette , Chagnaud Guillaume , Creutin Jean-Dominique
Published: March 2024

Droughts are recurrent phenomena that present a large variety of space and time patterns making rather difficult the assessment of their rarity and the comparison between events. Our study focuses on the space-time “memory effect” of meteorological drought over France using gridded precipitation from the SAFRAN reanalysis over 1950-2022. The proposed easy tool of rarity matrix analyzes how drought events build and persist across time and space. The approach is purely statistic, assuming that drought consequences over a given area depend on the probability of non exceedance (“rarity”) of antecedent rainfall accumulations. In order to cover a large spectrum of “memory effects”, we consider a continuum of accumulation periods ranging from a few weeks to several years and moving windows of size 80x80 to 480x480 km2 over France. The rarity matrix of a given year displays the most severe rarity values encountered during the year as a function of the various accumulation periods and the various spatial scales.Over the study period of 1950-2022 we show how the shape of rarity matrix discriminate short- and long-term historical droughts, as well as regional to national droughts. As an additional asset, the rarity matrix is also able to analyze the rarity of precipitation excess over several weeks to months or years, as it was the case in fall 2023 in France.
The performance of the Foreshock Traffic Light System for the period 2016-2024
Authors: Gulia Laura , Wiemer Stefan , Biondini Emanuele , Enescu Bogdan , Vannucci Gianfranco
Published: March 2024

Strong earthquakes are followed by countless smaller events, whose number decays with time: a posteriori, we call them aftershocks. Sometimes, this sequence is interrupted by a larger event, and the “aftershocks” turn out to be foreshocks. In 2019, Gulia and Wiemer have proposed traffic light tool, named the Foreshock Traffic Light System (FTLS), that can discriminate between foreshocks and aftershocks, by monitoring the size distribution of events closely. The model successfully passed the first near real-time test (Gulia et al., 2020). A new version of the code, that can run in real-time, has been recently developed; since testing is the essence of the scientific method and is fundamentally important in seismicity forecast evaluation, we here show the performance of the new version of the FTLS through pseudo-prospective and, when possible, real-time tests on the available seismic sequences between 2016 and 2024.
On the implementation of Leith viscosities in NEMO: Results from a forced global ocean model
Authors: Wilder Thomas , Kuhlbrodt Till
Published: March 2024

In CMIP6, eddy-permitting models (notably HadGEM3-GC3.1 N216ORCA025) were found to perform poorlyagainst their coarse-resolution counterparts, particularly in the Southern Ocean. Compared with N96ORCA1(1 degree), ORCA025 exhibited an enhanced warm bias, weakened Antarctic Circumpolar Transport (~ 60 Sv),overactive Antarctic gyres, and lower Antarctic sea-ice extent and volume. The poor performance of the eddy-permitting model has been attributed to their diﬀiculty in representing mesoscale processes at higher latitudes.Despite these shortcomings, eddy-permitting models remain desirable for their capacity to resolve meridionaltransports of heat and carbon, and ice-ocean interactions.The objective of this work is to improve the representation of mesoscale processes in ORCA025 through theimplementation of two viscosity schemes: 2D Leith and Quasi-Geostrophic Leith. These viscosity schemeshave been shown to improve interior mixing by mesoscale eddies in eddy-rich models. Both schemes offer aparameterised viscosity coeﬀicient that is flow and scale-aware, in contrast to a typical constant biharmonicviscosity employed in N216ORCA025.In a forced ocean configuration (GOSI9p8.0 ORCA025), both Leith schemes demonstrate a marked impact onthe ocean’s circulation and its properties compared to biharmonic viscosity. Here, the Leith schemes dampenthe eddy kinetic energy field and reduce the Antarctic circumpolar transport, with corresponding changes intemperature and salinity fields. Additional simulations, both forced and coupled, are ongoing and may providefurther insights into the different impacts of the Leith viscosity schemes on physical processes in eddy-permittingEarth system models.
Impact of melt accumulation on tidal heat production in Europa’s mantle
Authors: Kervazo Mathilde , Tobie Gabriel , Behounkova Marie , Dumoulin Caroline , Choblet Gaël
Published: March 2024

Volcanic activity at Europa’s seafloor is one of the key questions regarding the habitability of its subsurface ocean. The suitable conditions for hydrothermalism on Europa’s seafloor are conditioned by the heat released from the underlying silicate mantle, supplied by both radiogenic and tidal heating. The orbital resonance between Io, Europa, and Ganymede forces their orbit and maintains non-zero eccentricities. Tidal heating due to eccentricity tides on Io is so extreme that it  produces intense volcanism.  Even though tidal heating  in Europa’s silicate mantle is expected to be much weaker than on Io due to its greater distance to Jupiter,   Běhounková et al. [1] showed that it may still be sufficient to maintain Europa’s mantle in a partially molten state  for several tens to hundred millions of years, particularly during periods of increased eccentricity. Due to inefficient melt transport through the thick lithosphere of Europa [2], melt produced during periods of enhanced eccentricity may accumulate and in turn affect the tidal heating, as it is the case for Io, implying a possible runaway melt process in the silicate interior of Europa. In this context, the goal of this study is to evaluate the effect of melt accumulation on the tidal heat production of Europa’s silicate mantle. For that purpose, we follow the approach developed to model the solid tides in Io’s partially molten interior [3], taking into account the effect of melt on the viscoelastic properties of the mantle. We adapt it to the context of Europa, corresponding to a deeper and thinner asthenosphere than on Io. We show that, whatever the partially molten layer thickness, melt accumulation increases tidal heat production and tidal dissipation even exceeds radiogenic heating. For equivalent volume of accumulated melt, the thinner the layer, the more pronounced this effect is. Our results show that the accumulation of melt, over timescales consistent with the 3D model prediction of Běhounková et al. [1], may significantly affect the tidal dissipation amplitude and its pattern. The potential presence of such melt accumulations may be tested by future measurements by Europa Clipper and JUICE from the combined analysis of gravimetric, altimetric and magnetic data, which might reveal long-wavelength anomalies which could be confronted to our model prediction. [1] Běhounková et al., GRL, 48(3), e2020GL090077 (2021),  [2] Bland and Elder, GRL, 49(5), e2021GL096939 (2022). [3] Kervazo et al., A&A, 650, A72 (2021) 
Limiting factors in model performance for the multi-objective calibration of a pan-European, semi-distributed hydrological model for discharge and sediments
Authors: Brendel Conrad , Capell René , Bartosova Alena
Published: March 2024

An inevitable challenge faced during calibration of large-scale hydrological models is the task of reducing equifinality of various model structures and parameter sets. HYPE (Hydrological Predictions for the Environment) is a semi-distributed, continuous simulation hydrological model which provides alternative routines for many simulated processes and utilizes both domain-wide parameters and parameters tied to physiography. The fourth-generation HYPE model for the pan-European domain, E-HYPE4, was calibrated for discharge and sediments within a framework which allowed for the evaluation of factors limiting model performance. Calibration was performed using a multi-phase approach in which an initial multi-objective calibration for discharge and sediments was followed by an exhaustive sediment calibration to evaluate combinations of erosion and sedimentation/resuspension routines. During each calibration phase, ensembles of parameter sets and model routines were simultaneously evaluated against discharge, evapotranspiration, and sediment observations. In total, 20,000 candidate parameter sets were evaluated during the discharge calibration, and a further 20,000 candidate model setups were assessed during the sediment calibration. Model performance was best with a highly regionalized model, and the largest drop in achievable model performance occurred when transitioning from an ensemble of candidates to a single model setup for the full model domain. However, much of the gains in performance with a highly regionalized model could be achieved with a much less regionalized model. Inclusion of sediments in the discharge calibration process reduced equifinality, and evaluation of the erosion routines indicated that a simple index-based routine performed equally well as a more complex, process-based routine . Finally, analysis of model performance by subbasin attributes revealed the dominant factors — such as landuse, glaciers, abstractions/regulations, groundwater, and lakes/wetlands — affecting model biases for different geographical regions.
Characterization of an urban landfill with the transient electromagnetic and spectral induced polarization methods to quantify raw materials and map leakages
Authors: Aigner Lukas , Flores Orozco Adrian
Published: March 2024

Circular economy requires reliable information about the content of old landfills regarding raw materials worth exploiting. Geophysical electrical methods are standard tools for such investigations; however, they require a galvanic contact between electrodes and the ground. Many landfills are covered by a shallow isolating layer consisting of an electrically resistive material (e.g., a PVC layer), which hinders current flow and significantly decreases the resolution and the signal-to-noise ratio (SNR). Low-induction electromagnetic methods have also been suggested for such investigations; yet these methods have a limited depth of investigation. To overcome these limitations, we investigate the applicability of the transient electromagnetic method to characterize an industrial landfill. The investigation is based on a TEM survey to define the positions of two deep boreholes  The combination of borehole and geophysical data aims at identifying the composition and distribution of waste, a prerequisite to evaluate its potential content of raw materials. We conducted TEM measurements in a large industrial landfill (ca. 500 m long, 200 m wide and 20 m deep) sealed by an impermeable PVC layer. The objectives of the TEM survey are: 1) the delineation of the landfill geometry 2) locating possible changes in waste composition and 3) identifying damages in the isolating PVC layer which might result in leachate migration below the landfill. We obtain TEM data with the TEM-FAST 48 instrument in a 12.5 m square single-loop configuration at 81 sounding locations to cover the entire plateau of the landfill. We demonstrate that the TEM signatures are affected by induced polarization effects, which is likely related to the presence of molybdenum and other relevant raw materials. To evaluate this observation, we conducted complementary measurements with the spectral induced polarization method using a large electrode spacing to enhance the SNR. We validated the TEM results using two 40 m deep boreholes that reach from the top of the landfill into the confining clay-rich layer.
Effects of Stress on the Olivine–Spinel Phase Transformation in the Mantle: Griggs-Type Deformation Experiments Using Mg2GeO4 as an Analogue.
Authors: Akhtar-Lewis Scott
Published: March 2024

The effects of pressure and temperature on the phase transformation of olivine to wadsleyite and then ringwoodite within the mantle is well understood. However, the extent to which stress affects this phase transformation is not clear. Understanding how stress influences the kinetics of the olivine to spinel phase transformation and the mechanism in which it does so at grain scale, will have broader implications for mantle dynamics. Deformation experiments using Mg2GeO4 have been used as an approximate analogue for fayalite as it transforms from olivine to ringwoodite at lower pressures and temperatures rather than the conditions found at d410 (Vaughan, 1981). This enables the use of larger samples than possible for the silicate system, and allows for extensive microstructural investigations. This session aims to discuss high pressure deformation experiments on Mg2GeO4 (olivine) during the transformation to ringwoodite using a Griggs-type, solid medium, deformation apparatus. These experiments expand on (Vaughan 1984) which linked kinetics of the reaction in a model that matches other stressed reactions in the mantle (Wheeler, 2020). Experiments were conducted at a range of confining pressures 0.8 - 1.2 GPa at a fixed temperature of 900 °C and a strain rate of 10-6 /s. The four samples were deformed to finite strains ranging from 10 to 45 %. The aim of the conditions chosen was to apply varying amounts of differential stress and therefore differing the σ1 stress on the sample as a whole. Samples were characterised down to the level of individual interfaces using Electron Backscatter Diffraction (EBSD) to understand the physical mechanism of the reaction and the kinetics that govern it.
Long term ice-sheet albedo feedback constrained by most recent deglaciation
Authors: Booth Alice , Goodwin Philip , Cael Bb
Published: March 2024

Slow climate feedbacks that operate on timescales of more than a century are currently underrepresented in model assessments of climate sensitivity, and this continues to hinder efforts to accurately predict future climate change beyond the end of the 21st Century. As such, the magnitude of multi-centennial and millennial climate feedbacks are still poorly constrained. We utilise recent reconstructions of Earth’s Energy Imbalance (EEI) to estimate both the total climate feedback parameter and the ice-sheet albedo feedback since the Last Glacial Maximum. This new proxy-based record of EEI facilitates the first opportunity to simultaneously calculate both the magnitude and timescale of Earth’s climate feedback over the most recent deglaciation using a purely proxy data-driven approach, and without the need for simulated reconstructions. We find the ice-sheet albedo feedback to have been an amplifying feedback reaching an equilibrium magnitude of 0.55 Wm-2K-1, with a 66% confidence interval of 0.45 Wm-2K-1 to 0.63 Wm-2K-1. The timescale for the ice-sheet albedo feedback to reach equilibrium is estimated as 3.61Kyrs, with a 66% confidence interval of 1.88Kyrs to 5.48Kyrs. These results provide new evidence for the timescale and magnitude of the amplifying ice-sheet albedo feedback that will continue to drive anthropogenic warming for millennia to come, further increasing the urgency for an effective climate change mitigation strategy to avoid serious long-term consequences for our planet and its ecosystems.
Functionality assessment of road network combining flood roadworthiness and graph topology
Authors: He Ke , Pregnolato Maria , Carhart Neil , Neal Jeffrey , De Risi Raffaele
Published: March 2024

In the realm of critical infrastructure, the road network plays an indispensable role in facilitating daily activities, communication, and economic interactions. However, it remains susceptible to the persistent challenge of flood hazards, leading to both structural and non-structural damages (e.g., physical collapse and service interruption). In normal flood disasters, physical collapse may not occur, but service interruptions often occur. Such disruptions manifest in the form of increased travel distances, prolong the travel times, and, in severe cases, complete travel impossibility. This has resulted in a reduction in transportation efficiency, leading to an increase in the social cost of transportation.This study presents a novel approach that integrated flood hazard, transportation network topology, and vehicle vulnerability to evaluate the functionality of road network. A severity factor is defined to assess the accessibility of expected links (roads and bridges), considering different vehicle types such as cars and SUVs. Then, this study analyses the overall road network functionality loss under varying flood return periods by evaluating the severity of each network link based on the different types of vehicles. Identification of links with the lowest functionality allows for the assessment of the entire network’s performance using topology-based measures, including the average node degree, average clustering, average shortest path, and reachable areas (isochrones). This research employs the transportation network of Bristol, UK, as a case study to investigate the dynamic relationship between the network status and vehicle typology in the context of flooding events. Findings reveal a discernible correlation, wherein the resilience of the network in influenced by the specific characteristics of different vehicle types. Notably, SUVs emerge as inherently more resistant to flood-related disruptions compared to conventional cars.The insights presented in this paper hold significant implications for the development of robust mitigation strategies geared towards bolstering the resilience of road networks and optimizing the rerouting of emergency response vehicles in flood-prone areas. By elucidating the interplay between vehicle characteristics, network functionality, and flood impacts, the research provides a foundation for informed decision-making in the formulation and implementation of effective preparedness measures. The outcomes of this study offer a strategic roadmap for authorities and policymakers, enabling them to proactively address the challenges posed by future flood events and enhance the overall adaptability and responsiveness of road networks in emergency situations.
Ice crystal numbers in Arctic clouds over sea ice and ocean: satellite retrievals and cloud-resolving modelling
Authors: Papakonstantinou Presvelou Iris , Quaas Johannes
Published: March 2024

Mixed-phase and ice clouds are prominent parts of the Arctic climate system. In particular, boundary layer clouds and their interactions with local aerosols may play an important role in the amplified warming that has been observed in the Arctic during the recent years. These aerosols which are known as ice nucleating particles (INPs) are necessary for the heterogeneous ice formation in temperatures above -38oC. Several in-situ observations have measured a high number of effective ice nucleating particles, possibly related to biological activity in the open ocean. In contrast, in our previous study analyzing the novel active remote sensing dataset DARDAR-Nice for ten years in the Arctic region (Papakonstantinou-Presvelou et al., 2022), we found an increased ice number in low-level clouds over sea ice compared to the open ocean, suggesting other possible factors that might contribute to this difference. Here we perform several sensitivity experiments with the ICON model at kilometer-scale resolution in order to investigate the effect of these factors to the ice number, namely the contribution of local INPs, blowing snow and secondary ice production.
Analyzing Groundwater Hazards with Sequential Monte Carlo 
Authors: Friedli Lea , Linde Niklas
Published: March 2024

Analyzing groundwater hazards frequently involves utilizing Bayesian inversions and estimating probabilities associated with rare events. A concrete example concerns the potential contamination of an aquifer, a process influenced by the unknown hydraulic properties of the subsurface. In this context, the emphasis shifts from the posterior distribution of model parameters to the distribution of a particular quantity of interest dependent on these parameters. To tackle the methodological hurdles at hand, we propose a Sequential Monte Carlo approach in two stages. The initial phase involves generating particles to approximate the posterior distribution, while the subsequent phase utilizes subset sampling techniques to evaluate the probability of the specific rare event of interest. Exploring a two-dimensional flow and transport example, we demonstrate the efficiency and accuracy of the developed PostRisk-SMC method in estimating rare event probabilities associated with groundwater hazards.
Appearance of viral genomes with high GC base proportion in atmospheric samples from Europe and Antarctica
Authors: Rahlff Janina , Cockerton Luke , Amato Pierre , Pearce David A. , Marz Manja
Published: March 2024

Outdoor viruses from atmospheric ecosystems have rarely been investigated, and thus only a few viral genomes from the air can be found in public databases. Viruses and their hosts have positively correlating guanine-cytosine (GC) contents in their DNA1. High GC content was previously found in actinobacterial and betaproteobacterial isolates from the stratosphere2 as well as in aerosol and rainwater viruses3. This is proposed as an adaptation to harsh environmental conditions, primarily as protection against ultraviolet radiation. Here, we combine metagenomically derived viral operational taxonomic units (vOTUs) collected from aerosols and precipitation samples from the Swedish coast3, along with time-series data collected in Antarctica using different sampling devices. Additionally, cloud water samples from the Puy de Dôme in France4 were included. A total of 80 assembled vOTUs, of which 37 were predicted phages, across all samples, had a GC content between 55.2% and 70.3%, considered 'high GC.' Antarctic air vOTUs were found after sampling with the Coriolis µ (wet) but not with the Coriolis Compact (dry) air sampler. The time series indicates overlapping vOTUs between days and sampling height (sea-level or altitude). In Antarctic air, high GC vOTUs (mean GC = 59.6% ± 4.0) were detected on one of the seven days, while low GC viruses were absent in this sample. On other days, the GC of vOTUs was
An ensemble based approach for the effect of climate change on the dynamics of extremes
Authors: Jánosi Dániel , Herein Mátyás , Tél Tamás
Published: March 2024

In view of the growing importance of climate ensemble simulations, we propose an ensemble approach for following the dynamics of extremes in the presence of climate change. A strict analog of extreme events, a concept based on single time series and local observations, cannot be found. To study nevertheless typical properties over an ensemble, in particular if global variables are of interest, a novel, statistical approach is used, based on a ”zooming in” into the ensemble. To this end, additional sub-ensembles with initially very close members are generated around trajectories of the original ensemble. Plume diagrams initiated on the same day of a year are generated from these sub-ensembles. The trajectories within a plume diagram strongly deviate on the time scale of a few weeks. By defining the extreme deviation as the difference between the maximum and minimum values in a plume diagram, a growth rate for the extreme deviation can be extracted. An average of these taken over the original ensemble (i.e. over all sub-ensembles) characterizes the typical, exponential growth rate of extremes, and the reciprocal of this can be considered the characteristic time of the emergence of extremes. Using a climate model of intermediate complexity, these are found to be on the order of a few days, with some difference between the global mean surface temperature and pressure. Measuring the reciprocal of the growth rate in several years along the last century, results for the temperature turn out to be roughly constant, while a pronounced decaying trend is found in the last decades for the pressure.
Impact of inversion tectonics on the hydrocarbon trap development in the Qom-Saveh area: Insights from the Western Alborz Oilfield, Central Iran
Authors: Tajmir Riahi Zahra , Nikpoush Sadaf , Soleimany Bahman
Published: March 2024

Abstract:Deciphering inversion tectonics and identification of inverted structures are very important in the petroleum industry due to the positive or negative impacts they can exert on the hydrocarbon traps. The proper understanding of structures related to inversion has implications for geo-energy exploration. In order to characterize the occurrence of inversion tectonics and its effect in the Western Alborz Oilfield, located in the Qom-Saveh area (Central Iran), this research describes the structural style and deformation history through structural and tectono-sedimentary analyses based on the surface data (geological map and satellite image) and subsurface data (seismic data and well data). The results obtained from the interpretation of seismic profiles and the investigation of the geometry of the sedimentary layers across the growth structures indicate that the Western Alborz anticline is created from multiple fault-propagation folds. The final shape and geometry of the Western Alborz anticline are affected by thrust fault with the ram and flat geometry, reversed normal fault, and steeply dipping normal fault activity. The Western Alborz structure evolved at least during six tectonic phases. Three stages of the extensional deformation occurred from the Eocene to the Early Miocene. Moreover, three compressional phases happened in the Late Miocene and continued to the present day. During the Middle Miocene (Langhian-Serravallian), the tectonic quiescence period prevailed in this Oilfield. Multiple fault-propagation folding and the fold axis rotation in the Western Alborz anticline are controlled by the presence of décollement surfaces, the salt diapirism, and the occurrence of inversion tectonics along the pre-existing basement structure. Based on the structural evidence of inversion tectonics and the deformation history in the study area, the positive inversion tectonics occurred at the Middle to Late Miocene boundary and modified the evolutionary history of the sedimentary basin. Inversion affected hydrocarbon trap development at the Late Miocene and controlled their current conditions in Central Iran. Considering the hydrocarbon migration after the Late Miocene in the Central Iran basin up to the present day, the inversion tectonics event has a positive impact on the hydrocarbon trap development in the Western Alborz Oilfield. The results of this study could add data to worldwide examples of the positive impacts of tectonic inversion on the hydrocarbon trap development in collisional orogenic belts. Keywords: Inversion tectonics; Tectono-sedimentary analysis; Hydrocarbon trap; Western Alborz Oilfield; Central Iran
The Frictional Strength and Stability of Spatially Heterogeneous Fault gouges
Authors: Arts Job , Niemeijer André , Drury Martyn , Willingshofer Ernst , Matenco Liviu
Published: March 2024

Along-fault lithological heterogeneity is observed in all fault zones that cross-cut compositional layering. Modelling studies of fault rupture nucleation, propagation and arrest often assume that the fault mechanical behaviour is governed by either the rheologically weakest phase or by homogeneous gouge mixtures of the juxtaposing lithologies. However, the effects of spatial heterogeneity on fault gouge composition and hence its frictional behaviour are not well understood.In this study, we conducted friction experiments to understand how material mixing and clay-smearing in fault gouges affect the frictional strength and stability of claystone-sandstone juxtaposing faults. Simulated mechanically contrasting fault gouges (Ten Boer claystone and Slochteren sandstone) were derived from the Groningen gas field in the northeast of the Netherlands, an area affected by induced seismicity. We conducted velocity stepping tests in a rotary shear configuration to facilitate substantial shear displacement, essential to study mixing and clay-smearing in large offset faults. Experiments were performed under normal stresses ranging between 2.5 and 10 MPa, imposed velocities ranging between 10 and 1000 µm/s, and under drained conditions. We introduced spatial heterogeneity by segmentation of the simulated gouge in claystone and sandstone patches.Our mechanical data shows displacement-dependent changes in sliding friction and its rate-dependence. Clay smearing and shear localization on foliation planes cause transient weakening of the gouge and a shift from velocity-weakening to velocity-strengthening behaviour. Progressive shearing leads to juxtaposition of sandstone segments that are separated only by a thin clay smear. We propose that the associated increase in friction is caused by lithology mixing at the interfaces between the clay smear and the bulk Slochteren sandstone gouge, and by the disruption of continuous Y-shears. Progressive shearing does not lead to a decrease in the rate-sensitivity parameter (a-b), suggesting that, although affected by quartz and feldspar grains, deformation remains localized on phyllosilicate foliation planes.Our results show that fault friction and its rate-dependence are not simply governed by the weakest lithology along a fault plane, nor that they can be simply represented by a homogeneous mixture of the juxtaposing lithologies. Detailed knowledge of the stratigraphic layering in combination with the fault offset is required to predict the macroscopic frictional behaviour of heterogenous fault gouges.
Using TROPOMI observations to derive methane emissions and its driving factors over Lake Chad
Authors: Liu Mengyao , van der A Ronald , Liu Ruoqi , van Weele Michiel , Zhang Geli , de Laat Jos , Veefkind Pepijn
Published: March 2024

Wetland methane emissions are an important source of uncertainty in the methane budget due to their significant spatial and temporal variabilities. The Lake Chad Basin is located in central Africa and comprises a number of transboundary waters, which exhibit dramatic expansion and contraction. However, methane emissions from Lake Chad seem not to be properly captured in bottom-up emission inventories. An improved divergence method has been developed to estimate gridded methane (CH4) emissions from satellite observations of the TROPOspheric Monitoring Instrument (TROPOMI). Significant annual methane emissions over the Lake Chad Basin are identified by both the official reprocessed (S5P_RPRO_L2__CH4) and WFM-DOAS (TROPOMI/WFMD v1.8) XCH4 products. The maximum methane emissions appear from December to February while the minimum emissions are found during June to August. We further extract the monthly surface water areas using Landsat satellite imagery and wetland areas based on the MODIS vegetation index. The monthly variations of methane emissions are consistent with monthly surface water areas and wetlands areas but in contrast to the monthly rainfall. The seasonal emissions during the period of 2018 to 2022 over the Lake Chad Basin have been studied to better understand the role of driving factors such as rainfall, temperature, and waterlogged soils.
A model perspective on the drivers of the shallow oxygen minimum zone off the northwestern African coast
Authors: Cardoso Cláudio , Calil Paulo , Caldeira Rui M. A. , Peliz Álvaro
Published: March 2024

The Oxygen Minimum Zone (OMZ) off the coast of Mauritania and Senegal is characterized by a shallow and a deep oxygen minimum, each with potentially different formation mechanisms. Although the shallow OMZ has been linked to the en-route degradation of organic matter within highly productive, coastal-generated eddies, less attention has been paid to hypoxic Dissolved Oxygen (DO) concentrations observed along the coastal region, where low-oxygen eddies are formed. This study aims to clarify the spatio-temporal dynamics and underlying mechanisms that lead to the formation of the shallow OMZ along the northwestern African coast.To achieve this, a Eulerian-Lagrangian numerical framework was employed by combining a coupled physical-biogeochemical model with a Lagrangian particle-tracking simulation. The model domain covers the entire Tropical Atlantic with an horizontal resolution of 3 km, achieving a good representation of the horizontal and vertical structure of the North Atlantic OMZ. To assess the pathways and evolution of the water masses that form the shallow OMZ, lagrangian particles were released in grid cells with DO < 40 μmol.l-1 and traced backwards in time.Our results reveal distinct seasonal and latitudinal variations of DO concentrations along the coast, with DO concentrations significantly decreasing in the transition from the upwelling to the relaxation season (from May to July). Associated with the transport of more oxygenated South Atlantic Central Waters (SACW), the influence of the Poleward Undercurrent (PUC) on the ventilation of the coastal region is evident, especially when the current loses intensity and becomes a surface-intensified feature in summer. When the PUC reaches its maximum intensity in autumn, its core deepens below the mixed layer and replaces the older, oxygen-poor waters with ventilated waters of southern origin.The impact of eddies on coastal dynamics was also explored. A quasi-permanent Anticyclonic Modewater Eddy (ACME) formed during the upwelling season by the interaction of the PUC with the Cap-Vert headland is the main mechanism behind the import of offshore waters to the coastal region. Lagrangian particle trajectories suggest that this eddy prevents the direct northward transport of SACW by the PUC. Whilst some of the particles are trapped and subsequently transported offshore inside the eddy, other particles are stirred with an older, less oxygenated SACW variety in the offshore region and re-circulate to the coastal region. Similar particle re-circulation patterns are also observed further north, coinciding with cyclonic and ACME formation hotspots.Our findings suggest that in addition to their role in the formation and advection of oxygen-depleted waters to offshore, coastal-generated eddies play a crucial role in modulating DO levels along the northwestern African coast.