bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluating the crisis communications campaign during the 2020-2021 eruption of La Soufriere, St Vincent. 
Authors: Mani Lara , Edwards Stacey , Juman Alia , Thomas Thalia , Joseph Erouscilla
Published: March 2022

During the 2020-2021 eruption of La Soufriere, St. Vincent, the Seismic Research Centre at The University of the West Indies (SRC) played a major role in supporting communication of hazard and risk information to publics and stakeholders across St. Vincent. Due to COVID-19 restrictions, the communications campaign was heavily reliant on social media channels and TV and radio broadcasts, rather than in-person community education and communication sessions. Although the communications approach sought to be inclusive of all members of the affected communities where possible, it was considered possible that the more vulnerable residents, such as the elderly, children, and those with low levels of literacy were excluded from the communication efforts.

In order to establish the effectiveness of the crisis communications campaign at engaging communities and stakeholders with relevant information and to identify areas for improvement, a large-scale evaluation campaign was conducted in St Vincent in August 2021. The results demonstrate that radio broadcasts are the most important communication tool for broad community reach, but that person-to-person information sharing was more important in the most exposed communities. Agencies such as the Red Cross and grassroots community disaster preparedness groups were instrumental in the spread of information to those most vulnerable within the most at-risk communities and for evacuation coordination. However, social media was also found to be highly effective at communicating information to the diaspora, which in turn was communicated to family and friends on the island through mediums such as WhatsApp.

Here we present some of the early findings of this research and provide suggestions and considerations to inform future crisis communication campaigns in St. Vincent and the wider Caribbean region.
Towards seismic velocity monitoring using anthropogenic seismic signals
Authors: Sheng Yixiao , Mordret Aurélien , Sager Korbinian , Brenguier Florent , Boué Pierre , Rousset Baptiste , Vernon Frank , Ben-Zion Yehuda
Published: March 2022

Anthropogenic seismic signals attract more and more attention in recent years. Freight trains, among different seismic sources, are of particular interest for seismic velocity monitoring due to several advantages. Trains are persistent, powerful sources that generate seismic tremors equivalent to Mw 2 earthquakes and detectable up to 100 km distance; trains move along fixed trajectories, allowing us to properly account for the source distribution and its coupling between the structure; trains generate high-frequency body-wave energy enabling us to focus on the changes at depth with high spatial resolution. We propose a fault zone monitoring framework through a case study in southern California. Freight trains running through the Coachella Valley are used to monitor changes associated with the San Jacinto Fault. The general steps include identifying sources and constructing a train catalog, extracting body waves through seismic interferometry, measuring travel-time perturbation, and mapping seismic velocity change. We analyze the seismic data from 2010 to 2020 and discover an episode of velocity changes in early 2014, manifested on all station pairs considered. The velocity perturbation shows a complicated spatial pattern, with some station pairs exhibiting positive changes, and others negative changes. We interpret that this velocity perturbation results from an aseismic slip near the edge of the Anza seismic gap and further validate this idea using numerical simulations. We use the Coulomb software to simulate volumetric strain for velocity perturbation and full-waveform modeling to simulate correlation functions for estimating travel-time change. The proposed framework has great potentials to be applied in other settings, from wastewater injection to CO2 sequestration, using freight trains or other type of anthropogenic sources.
Tipping risks due to temperature overshoots within the Paris range
Authors: Wunderling Nico , Winkelmann Ricarda , Rockström Johan , Loriani Sina , McKay David A. , Ritchie Paul , Sakschewski Boris , Donges Jonathan F.
Published: March 2022

Climate tipping elements potentially lead to accelerated and irreversible climate change once their critical temperature threshold is passed. Some of their critical thresholds (tipping points) are at risk to be transgressed already within the temperature guardrails of 1.5-2.0°C above pre-industrial levels. However, it has been suggested at the same time that global mean temperature levels are likely to temporarily overshoot these boundaries.

Therefore, we investigate the tipping risk for a set of four interacting climate tipping elements using a conceptual model. To this end, we study the impact of different peak and long-term saturation temperatures on the Greenland Ice Sheet, the West Antarctic Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest.

We find that overshoot peak temperatures between 2.5-4.0°C increase the risk by 10-55% even if long-term global mean temperature levels are stabilized between 1.5-2.0°C. Furthermore, the interactions between the tipping elements increase tipping risks significantly already at modest to intermediate levels of interaction. Therefore our conceptual study suggests that safe overshoots are only possible for low peak temperatures of the overshoot as well as final saturation temperatures at or below today’s global warming levels.
Positive and negative phases of the North Atlantic Oscillation – not just images in the mirror
Authors: Christensen Jens H. , Schmith Torben , Kirchner Anna I.K. , Yang Shuting , Olsen Steffen M.
Published: March 2022

The North Atlantic Oscillation (NAO) is the leading mode of atmospheric variability during winter in the North Atlantic region on time scales ranging from ~5-7 days over months to the entire winter season. It influences the weather and climate in the entire North Atlantic-European region and even beyond and has been recognised for centuries. It is scientifically characterised by the NAO index, which is essentially the pressure difference between the Azores and Iceland, in combination with a spatial pressure anomaly pattern. Often the NAO is regarded as consisting of positive or negative events with the duration of around one week with intermittent periods of near-neutral conditions, and the net number of events combined with their magnitude then form the NAO strength for the winter. Here we wish to point out that this picture appears too simplified. We find that the phase of the NAO outside the time horizon of one week has an influence on the shorter NAO type events, most pronounced for NAO- events where the influence can both distort and at the same time either amplify or diminish the NAO pattern. This has potential implications for seasonal or longer time-scale predictability in our region. In a similar manner, the well-known strong correlation between the phase and strength of the NAO with precipitation anomalies over Europe may be also skewed. We identify that on a monthly to seasonal time scale the correlation may be less significant for strong negative precipitation anomalies than appears to be the case for strong positive anomalies. In some of the examined data, specifically dry conditions in north-western Europe do not seem to show a clear connection to a particular phase of the NAO and thus cannot necessarily be used to derive information about the state of this atmospheric circulation pattern, an approach often taken when trying to reconstruct the atmospheric circulation based on proxy records.
2-D Sn attenuation tomography of Arunachal Himalaya
Authors: Sarkar Sukanta , Singh Chandrani , Kumar M. Ravi , Tiwari Ashwani Kant , Dubey Arun Kumar , Singh Arun
Published: March 2022

In this study, we have presented the first high-resolution 2-D Sn attenuation tomography image of
Arunachal Himalaya to enlighten the lithospheric structure of the area. The region is one of the
active segments of the Himalaya and least understood because of the inaccessibility and difficult
working conditions. 37 regional earthquakes within the epicentral distance of 250 - 1650 km were
recorded by 29 broadband seismic stations operated in Arunachal Himalaya covering the majority
portions of the eastern Himalaya are used in the present study.
Sn is the uppermost mantle refracted phase travelled with a velocity of 4.3 - 4.7 km/s. It
is highly sensitive to the velocity gradient and attenuation in the uppermost mantle. We have
categorised the propagation efficiencies of Sn as efficient, inefficient and blocked based on a
visual inspection. The inefficient and blocked Sn phases are observed mainly in the western side
of our study region. Further, we have obtained the Sn Q tomography model to examine lateral
variations in attenuation characteristics, employing the Two Station Method (TSM) using 567 station
pairs as input data. The central Arunachal Himalaya exhibits a low Q value (≤ 50) whereas
Tawang and the western part of Arunachal Himalaya show a high value of Q ≤ 300. The obtained
results are well correlated with the tectonic fabric of the area.
Electron heating scales in quasi-perpendicular shocks
Authors: Johlander Andreas , Dimmock Andrew , Khotyaintsev Yuri , Graham Daniel , Lalti Ahmad
Published: March 2022

Collisionless shock waves are important for particle heating and acceleration in space. Electron heating at shocks is a combination of adiabatic heating due to large-scale electric and magnetic fields and scattering by high-frequency oscillations. Electron heating and scattering at the shock is still poorly understood but the scales at which heating happens can hint to which physical processes are taking place. Here, we study electron heating scales with the Magnetospheric Multiscale (MMS) spacecraft at Earth’s quasi-perpendicular bow shock. We utilize the small tetrahedron formation and rapid plasma measurements of MMS to directly measure the electron temperature gradient inside the shock. From this, we reconstruct the electron temperature profile inside the shock ramps of a number of shock crossings with varying shock parameters. We find that most of the electron temperature increase takes place on a scale of tens of electron inertial lengths. Further, we investigate the electron distribution functions and attempt to disentangle the effects of the large-scale adiabatic heating and scattering by high-frequency waves.
Sediment load determines the shape of rivers 
Authors: Popovic Predrag , Devauchelle Olivier , Abramian Anais , Lajeunesse Eric
Published: March 2022

Understanding how rivers adjust to the sediment load they carry is critical to predicting the evolution of landscapes. Presently, however, no physically based model reliably captures the dependence of basic river properties, such as its shape or slope, on the discharge of sediment, even in the simple case of laboratory rivers. Here, we show how the balance between fluid stress and gravity acting on the sediment grains, along with cross-stream diffusion of sediment, determines the shape and sediment flux profile of laminar laboratory rivers that carry sediment as bedload. Using this model, which reliably reproduces the experiments without any tuning, we confirm the hypothesis, originally proposed by G. Parker (1978), that rivers are restricted to exist close to the threshold of sediment motion (within about 20%). This limit is set by the fluid–sediment interaction and is independent of the water and sediment load carried by the river. Thus, as the total sediment discharge increases, the intensity of sediment flux (sediment discharge per unit width) in a river saturates, and the river can transport more sediment only by widening. In this large discharge regime, the cross-stream diffusion of momentum in the flow permits sediment transport. Conversely, in the weak transport regime, the transported sediment concentrates around the river center without significantly altering the river shape. If this theory holds for natural rivers, the aspect ratio of a river could become a proxy for sediment discharge—a quantity notoriously difficult to measure in the field.
The great Arctic Eocene strike-slip zone Umky
Authors: Startseva Ksenia , Nikishin Anatoly , Rodina Elizaveta
Published: March 2022

On the seismic lines acquired in 2011-2020 for the North-Chukchi Sea and East Siberian Sea basins plenty of low-amplitude normal faults is identified. Maximal apparent throw of the faults is 100-200 ms, and occasionally reaches up to 300-400 ms. Dip angles of the faults are often directed towards each other, the resulting flower structure is related to strike-slip tension. For individual faults it is possible to ascertain strike azimuth – near 350° for the North Chukchi basin and near 340° in East Siberian basin. By the seismic data, the faults are distributed within an area of ~1.500 km long- and ~350 km wide.

According to interpretation, the faults activation occurred from 45 Ma to 34 Ma. This time corresponds to a regional tectonic rebuilding, that is observed across all the region. For example, a sharp slowdown of the Eurasian Basin spreading had place then. Formation of the North-Chukchi and East Siberian basins is related to Aptian-Albian (~125 Ma) rifting, that manifested itself on the De Long Islands and the Mendeleev Rise. Isometric form of the basins could indicate the conditions of pull-apart tension. Data of gravity and magnetic anomalies support this assumption – a long linear anomaly of ~285° strike is identified to the North of the Wrangel Island (in Chukchi, the last is called Umkilir – “White Bear Island”). The anomaly is interpreted as regional strike-slip that was formed ~125 Ma. The angle between the strike-sleep and the multiple low-amplitude Eocene faults is about 55-65°. It is possible to relate the low-amplitude faults to the reactivation of the great strike-slip.

This study was supported by the Russian Science Foundation (Grant 22-27-00160).
The key controls of thallium isotopic fractionation in soil
Authors: Vejvodová Kateřina , Vaněk Aleš , Mihaljevič Martin , Ettler Vojtěch , Trubač Jakub , Vaňková Maria , Drahota Petr , Vokurková Petra , Penížek Vít , Zádorová Tereza , Tejnecký Václav , Pavlů Lenka , Drábek Ondřej
Published: March 2022

The purpose of this study was to investigate the key geochemical and mineralogical factors that could affect the fractionation of stable thallium (Tl) isotopes in soil. A set of grassland soil samples enriched in geogenic Tl in combination with selected Tl-containing mineral materials from the Czech Republic (Kluky) were investigated for this purpose. A combination of X-ray diffraction analysis (XRD), chemical extractions and stable isotope analysis were used to understand the behaviour of Tl and its isotope systematics within the soil profile. The results demonstrate significant incorporation of Tl in pedogenic Mn-oxide, which led to a large accumulation of the heavy 205Tl isotope (~+14 ε205Tl units), presumably resulting from continuous redox reactions with Mn-oxides and systematic accumulation of heavy isotope fraction onto the oxide surface(s). Consequently, we concluded that the Mn-oxide-controlled Tl uptake is the primary cause of the observed 205Tl enrichment in the middle profile zone, at the A/B soil horizon interface, with up to +4 of ε205Tl. Furthermore, our results displayed a clear relationship between the Tl isotopic fractionation degree and the Mn-oxide soil concentration (R2 = 0.6), as derived from the oxalate-extractable data. A combination of soil and mineralogical considerations suggests that 205Tl enrichment in the soil samples is also partly due to the Tl present in micaceous clay minerals, mainly illite, which is the predominant pedogenic Tl host phase. Supported by our previous results, this Tl behaviour can be inferred from systematic Mn-oxide degradation and the associated Tl (enriched in 205Tl) cycling in the studied soils and therefore, presumably in the redoximorphic soils in general.
Links between the spatial distribution of the surface urban heat island and heat-related mortality in Prague, Czech Republic
Authors: Dogan Tugba , Urban Aleš
Published: March 2022

Episodes of extremely high temperatures (heatwaves) are associated with an increased risk of human mortality. People living in cities are at the most significant risk of heat-related mortality due to the urban heat island effect. Although most studies investigate the impact of heat stress on mortality in a city as a whole, the magnitude of the heat stress in a particular part of the city depends on its physical characteristics.

Our study aims to investigate spatio-temporal links between the spatial distribution of the surface urban heat island intensity (SUHII) and heatwave-related mortality in Prague, the Czech Republic. We will analyse daily all-cause mortality in ten Prague districts between 2001 and 2010. A mortality baseline in each district will be determined using generalized additive models adjusted for long-term trends and seasonal and weekly cycles. Relative deviations from the baseline mortality will be calculated to quantify excess mortality during heat waves, defined as periods of at least three consecutive days with a mean daily temperature higher than the 95th percentile of the annual distribution. Six major heatwaves will be selected to investigate the links between the spatial distribution of SUHII and heat wave-related mortality. Daily MODIS land surface temperature images will be used to analyse the spatio-temporal changes in SUHII during the major heatwaves. Spatial statistics tools in ArcGIS will be used to investigate the spatio-temporal patterns.

Our study hypothesizes that the spatial distribution of heat-related mortality is associated with the distribution of SUHII during the major heatwaves. Due to climate change, the frequency and intensity of heatwaves are expected to increase, and the urban heat island intensity is likely to increase in response to heatwaves. The results of our study will help to identify areas in Prague with the most significant impact of urban design on heat-related mortality. This information is vital for identifying hot spots of heat-related mortality and developing strategies to mitigate heat stress in the city.
Multiple hazards and public risk perceptions under COVID-19
Authors: Di Baldassarre Giuliano , Raffetti Elena , Mondino Elena
Published: March 2022

The salience of global crises, such as COVID-19 and climate change, have plausibly influenced how people characterize and assess multiple hazards. In this study, we examine and compare how global crises and local disasters influence public perceptions of multiple hazards in Italy and Sweden by integrating the results of nationwide surveys with information about the occurrence of hazardous events. These included more than 4,000 participants and were conducted in three different phases of the COVID-19 pandemic (August 2020, November 2020 and August 2021), corresponding to various levels of infection rates. In line with the cognitive process known as the availability heuristic, we found that people are more worried about risks related to experienced events. In both countries, individuals assess the risk associated with a given hazard based on how easily it comes to their mind. Moreover, notwithstanding the ongoing pandemic, people in both Italy and Sweden are highly concerned about climate change, and they rank it as the most likely threat. Lastly, we found that public perceptions of multiple hazards are deeply intertwined. These outcomes do no only increase our knowledge on the way in which global crises and hazardous events shape public risk perception across different contexts, but also have the potential to inform communication strategies aiming to reduce disaster risk while supporting climate change adaptation.
Abundant multistability and intermediate tipping points in a global ocean model
Authors: Lohmann Johannes
Published: March 2022

Several climate sub-systems are believed to be at risk of undergoing abrupt, irreversible changes as a tipping point (TP) in Greenhouse gas concentrations is reached. Since the current generation of climate models is likely not accurate enough to reliably predict TPs, a hope is to anticipate them from observations via early-warning signals (EWS). EWS have been designed to identify generic changes in variability that occur before a well-defined TP is crossed.

Such well-defined, singular TPs are believed to arise from a single dominant positive feedback that destabilizes the system. However, one may ask whether the large number of spatio-temporal scales in the climate system, and associated second-order feedbacks, could not lead to a variety of more subtle, but discontinuous reorganizations of the spatial climate pattern before the eventual catastrophic tipping. Such intermediate TPs could hinder predictability and mask EWS.

We performed simulations with a global ocean model that shows a TP of the Atlantic meridional overturning circulation (AMOC) due to freshening of the surface waters resulting from increased ice melt. Using a large ensemble of equilibrium simulations, we map out the stability landscape of the ocean circulation in high detail. While in a classical hysteresis experiment only one regime of bistability is found, by very slow increases in forcing we observe an abundance of discontinuous, qualitative changes in the AMOC variability. These are used to initialize smaller-scale hysteresis experiments that reveal a variety of multistable regimes with at least 4 coexisting alternative attractors.

We argue that due to chaotic dynamics, non-autonomous instabilities, and complex geometries of the basins of attraction, the realized path to tipping can be highly sensitive to initial conditions and the trajectory of the control parameter. Further, we discuss the degree to which the equilibrium dynamics are reflected in the transient dynamics for different rates of forcing. The results have implications regarding the expected abruptness of TPs, as well as their predictability and the design of EWS.
Non-linear ground response triggered by volcanic explosions at Etna Volcano, Italy
Authors: Jousset Philippe , Costes Lucile , Currenti Gilda , Schwarz Benjamin , Napoli Rosalba , Diaz Sergio , Krawczyk Charlotte
Published: March 2022

Volcanic explosions produce energy that propagates both in the subsurface as seismic waves and in the atmosphere as acoustic waves. We analyse thousands of explosions which occurred at different craters at Etna volcano (Italy) in 2018 and 2019. We recorded signals from infrasound sensors, geophones (GPH), broadband seismometers (BB) and Distributed Acoustic Sensing (DAS) with fibre optic cable. The instruments were deployed at Piano delle Concazze at about 2 to 2.5 km from the active craters, within (or onto) a ~300,000 m2 scoria layer deposited by recent volcanic eruptions. The DAS interrogator was setup inside the Pizzi Deneri Volcanic Observatory (~2800 m elevation). Infrasonic explosion records span over a large range of pressure amplitudes with the largest one reaching 130 Pa (peak to peak), with an energy of ca. 2.5x1011 J. In the DAS and the BB records, we find a 4-s long seismic “low frequency” signal (1-2 Hz) corresponding to the seismic waves, followed by a 2-s long “high-frequency” signal (16-21 Hz), induced by the infrasound pressure pulse. The infrasound sensors contain a 1-2 Hz infrasound pulse, but surprisingly no high frequency signal. At locations where the scoria layer is very thin or even non-existent, this high frequency signal is absent from both DAS strain-rate records and BB/GPH velocity seismograms. These observations suggest that the scoria layer is excited by the infrasound pressure pulse, leading to the resonance of lose material above more competent substratum. We relate the high frequency resonance to the layer thickness. Multichannel Analysis of Surface Wave from jumps performed along the fibre optic cable provide the structure of the subsurface, and confirm thicknesses derived from the explosion analysis. As not all captured explosions led to the observation of these high frequency resonance, we systematically analyze the amplitudes of the incident pressure wave versus the recorded strain and find a non-linear relationship between the two. This non-linear behaviour is likely to be found at other explosive volcanoes. Furthermore, our observations suggest it might also be triggered by other atmospheric pressure sources, like thunderstorms. This analysis can lead to a better understanding of acoustic-to-seismic ground coupling and near-surface rock response from natural, but also anthropogenic sources, such as fireworks and gas explosions.
Livestock exposure to future cumulated climate-related stressors in West Africa
Authors: Brouillet Audrey , Sultan Benjamin
Published: March 2022

As global warming is projected to intensify according to model simulations, a large range of resulting impacts and stressors is expected during the 21st century. Severe impacts are particularly projected in vulnerable regions such as West Africa, where local populations largely rely on livestock systems as their main food production and income source. As climate change threatens livestock systems in various ways, here we assess how regional livestock could be exposed to cumulated and cross-sectoral climate stressors during the upcoming decades. A set of eight major risk indicators that may affect livestock is assessed and illustrate changes in food availability, heat stress, flood and drought risks. Corresponding simulations are analysed from the largest multi-model climate-related impact simulations database ISIMIP.

Under the RCP8.5 scenario, we find that a large part of West Africa will experience at least 5 to 6 cumulated cross-sectoral climate stressors before the 2030s, including amplified severe heat stress conditions and flood risks. Consequently, about 30% of total west african livestock will be affected by these cumulated stressors, with highest exposures shown for sheeps and cattles (respectively 39% and 38% of their total regional density). Multi-model means show that these species will be first exposed to significant intensification of severe heat stress conditions from early 2020s, then to more flood risks from 2030s. This study brings new quantifications that could help policy makers to prioritize decisions to prepare local populations to face multiple climate-related impacts.
Slow-release fertilizers from liquid digestate: amount and speciation of the N leached in a laboratory column experiment
Authors: Ferretti Giacomo , Galamini Giulio , Medoro Valeria , Faccini Barbara , Coltorti Massimo
Published: March 2022

The inefficient management of fertilizers is dramatically impairing the soil, water, and atmosphere quality. Efficient alternative methodologies for granting adequate N availability to crops while reducing the nutrient losses in the environment are urgently needed. In this work, we present a column leaching experiment in which the amount and speciation of the N lost by different slow-release fertilizers were investigated, in comparison to traditional fertilizers (urea and liquid digestate). The slow-release alternatives are produced by recovering N from liquid digestate and represented by NH4-enriched zeolite-rich tuff and struvite. Four treatments were tested consisting in sandy soil fertilized with urea, liquid digestate, NH4-enriched zeolite tuff and struvite. N amount and speciation was accounted in eight flushing events over 38 days (Total Kjeldahl N, Organic-N, NH4+-N, NO3--N, NO2--N).

Results showed that urea and liquid digestate fertilized columns lost the majority of N within the first 2 flushing events as organic N and NH4+-N, respectively. On the contrary, struvite and NH4-enriched zeolite fertilized columns lost homogeneously fewer N and with a more balanced speciation over the entire experiment length. The mass balance outlined that, native soil N was mined in urea and liquid digestate treatments while in the soil fertilized with slow-release alternatives a fraction of N from the fertilizers was still present. These two slow-release alternatives thus representing a way to recycle N from liquid digestate and to use it more efficiently, minimizing N losses.
Glacio-chemical signature of grain boundaries and insoluble particle aggregates in ice core 2D impurity imaging
Authors: Bohleber Pascal , Stoll Nicolas , Delmonte Barbara , Pelillo Marcello , Roman Marco , Siddiqi Kaleem , Stenni Barbara , Vascon Sebastiano , Weikusat Ilka , Barbante Carlo
Published: March 2022

Identifying, understanding, and constraining post-depositional processes altering the original layer sequence in ice cores is especially needed in order to avoid misinterpretation of the oldest and most highly thinned layers. The record of soluble and insoluble impurities represents an important part of the paleoclimate proxy set in ice cores but is known to be affected post-depositionally through interaction with the ice matrix, diffusion and chemical reactions. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been recognized for its micron-scale resolution and micro-destructiveness in ice core impurity analysis. Important added value comes from employing LA-ICP-MS for state-of-the-art 2D chemical imaging. The latter has already revealed a close relationship between the ice grain boundary network and impurity signals with a significant soluble component, such as Na. Here we show the latest improvements in 2D chemical imaging of ice with LA-ICP-MS, by increasing the spatial resolution from 35 to 20 and even 10 µm and extending the simultaneous analysis to cover also mostly insoluble impurity species, such as Al. The latter reveal clear signals of insoluble particle aggregates in samples of Greenland ice cores. Combining the chemical images with computer vision-based image analysis allows to separate the geochemical signals of grain boundaries and insoluble particles. Considering intensities as well as elemental ratios, this classification further highlights important differences in the geochemical signals depending on the location of the impurities in the ice matrix. Ultimately, we discuss how this refined approach may serve to investigate post-depositional changes occurring with increasing depth to the soluble and insoluble impurity components, based on grain growth and chemical reactions, respectively.
Machine learning-based modeling of deep-sea polymetallic nodules spatial distribution: spatial autocorrelation and model transferability at local scales
Authors: Gazis Iason - Zois , Greinert Jens
Published: March 2022

The spatial distribution of deep-sea polymetallic nodules (PMN) is of high interest due to increasing global demand in metals (Ni, Co, Cu), and their significant contribution to deep-sea ecology as hard-substrate. The spatial mapping is based on a combination of multibeam echosounders and underwater images in parallel to traditional ground-truth sampling by box coring. The combined analysis of such data has been advanced by using machine learning approaches, especially for automated image analyses and quantitative predictive mapping. However, the presence of spatial autocorrelation (SAC) in PMN distribution has not been extensively studied. While SAC could provide information regarding the patchy distribution of PMN and thus enlighten the variable selection before machine learning modeling, it could also result in an over-optimistic validation performance when not treated carefully. Here, we present a case study from a geomorphologically complex part of the Peru Basin. The local Moran’s I analysis revealed the presence of SAC of the PMN distribution, which can be linked with specific seafloor acoustic and geomorphological characteristics such as aspect and backscatter intensity. A quantile regression forests (QRF) model was developed using three cross-validations (CV) techniques: random-, spatial-, and feature space cluster-blocking. The results showed that spatial block cross-validation is the least unbiased method. Opposite the commonly used random-CV overestimates the true prediction error. QRF predicts well in morphologically similar areas, but the model uncertainty is high in areas with novel feature space conditions. Therefore, there is the need for dissimilarity analysis and transferability assessment even at local scales. Here, we used the recently proposed method “Area of Applicability” to map the geographical areas where feature space extrapolation occurs.
Controls on along-strike variations of basin development: a case study of the Northern Alpine Foreland Basin
Authors: Eskens Lucas , Andrić-Tomašević Nevena , Süss Peter M. , Ehlers Todd A. , Herrmann Rolf , Müller Matthias
Published: March 2022

The Northern Alpine Foreland Basin developed in response to the collision between the European and Adriatic plates. During the Oligocene-Early Miocene coeval along-strike deposition of terrestrial and deep marine conditions are recorded in the western and eastern parts of the basin respectively. However, the mechanisms driving the observed variability in along-strike development of the basin are still poorly understood.

To study the causes of the observed along-strike variability we review published geological data and (re)interpret available 2D and 3D seismic data, constrained by well data. We interpret (1) seismic facies, (2) stratigraphic surfaces and (3) tectonic structures. Our current focus area covers the transitional zone between the western and eastern parts of the basin.

In our study we distinguish 6 stratigraphic surfaces from the Base Tertiary to the Top Aquitanian. From Upper Swabia to the German-Austrian border (along the basin strike) we observe that the top of the crystalline basement is tilted towards the east with an angle of 2-3°. Furthermore, the base of the Tertiary deposits is also tilted towards the east with an angle of 0.3°. The main structural features are E-W and NW-SE striking normal faults. In the western part of our study area the normal faults cut the crystalline basement, Mesozoic and Oligocene deposits. The faults are sealed by Rupelian deposits. Thickness changes (~20 m) occur in Rupelian and overlying Chattian deposits. Maximum offsets of up to 60 m are observed for Mesozoic reflectors. In the eastern part of our study area the normal faults cut the crystalline basement, Mesozoic, Oligocene and Early Miocene deposits. Thickness changes across these faults indicate fault activity during the Rupelian, Chattian and Aquitanian. Maximum offsets (>150 m) are observed for Chattian reflectors. Upper Aquitanian deposits seal these faults, which is younger than observed in the western part of the study area. The NW-SE striking faults confine Paleozoic grabens within the crystalline basement.

We relate the observed normal faulting of the Oligocene and Early Miocene deposits to flexural downbending of the European plate, assumed to have been caused by tectonic loading of the Alps and/or European slab pull. Furthermore, we suggest that the observed temporal variation in termination of fault activity is related to temporal and spatial variations in tectonic loading of the Alps and/or European slab pull. Finally, based on the observed eastward tilt of the top crystalline basement and Base Tertiary along the basin strike, variations in pre-existing crustal architecture must be considered.
Observing small-scale ocean surface dynamics and vertical ocean processes in coastal, shelf and polar seas with the Earth Explorer 11 SEASTAR mission candidate.
Authors: Gommenginger Christine , Martin Adrien
Published: March 2022

High-resolution satellite images of sea surface temperature and ocean colour reveal an abundance of ocean fronts, swirls, vortices and filaments at horizontal scales below 10 km that permeate the global ocean, especially near mesoscale jets and eddies, in coastal seas and close to sea ice margins. These small-scale ocean features are the fingerprints of dynamic atmosphere-ocean interactions and intense ocean vertical processes that mediate exchanges across all the fundamental interfaces of the Earth System – between the atmosphere, the ocean surface, the ocean interior, the cryosphere and land – and impact major aspects of the global climate system.

Numerous research studies and high-impact scientific publications confirm the key role of submesoscale processes in air-sea interactions, upper-ocean mixing, lateral transports and vertical exchanges with the ocean interior. Small-scale processes also visibly dominate in coastal, shelf seas and polar seas - regions of disproportionally high strategic and societal value as hosts to numerous human activities and natural resources. This paper will review some of the evidence about the fundamental role of small-scale ocean dynamics in the Earth System, making the case for new observations from space to characterise these important phenomena. The contribution ends by outlining the science drivers and objectives of the SEASTAR satellite candidate mission currently under study as one of four candidates to the European Space Agency Earth Explorer 11 programme.
Wastewater treatment plant discharged phosphorus impacts the release of arsenic from arsenic-enriched streambed sediment
Authors: Venhauerova Petra , Drahota Petr , Strnad Ladislav , Matoušková Šárka
Published: March 2022

Phosphate competition with arsenic is one of the leading causes of As release from sediments into freshwaters. An important P source to freshwaters is wastewater treatment plants (WWTP), estimated to contribute 25–45% of all P in surface waters.

A stream surrounded by soils and sediments with naturally elevated concentrations of As (> 200 mg/kg) and continuous entry of small capacity WWTP discharge was studied. The methods used were XRD, EPMA, bulk analyses, single extractions, and batch leaching experiments. Since 2013, the WWTP effluent supplies 7–23 mg/l of PO4 into the stream and an increased concentration of As (150–180 µg/l) due to everyday usage of As‑enriched wells water in the households. This study revealed that the fractionation of As and P in sediments changed due to exposure to treated wastewater. The adsorbed As fraction decreased by 9 %, whereas the adsorbed P fraction increased by 9 % in the downstream samples. As a result, the P‑retention capacity of the sediment decreased in the downstream samples from 16 % to 10–12 %. These findings are supported by a mineralogical study, which showed that P and As distribution within the Fe (hydr)oxides differed significantly between the samples taken upstream and downstream of the effluent discharge point. The samples upstream showed higher As and lower P median concentration (1.3 wt % of As2O5 and 0.8 of P2O5 wt %, respectively), while the opposite behavior was observed downstream: As 0.7 wt % of As2O5 and P 1.6 wt % of P2O5. These findings indicate that elevated phosphate is replaced by arsenate in the Fe (hydr)oxides, and the As is mobilized into the aqueous phase. Moreover, a detailed mineralogical investigation of samples exposed to the P-enriched effluent showed newly created Fe (hydr)oxide coatings significantly enriched in P (< 18.2 wt % of P2O5), Ca (< 10.9 wt % CaO) while depleted in As (< 3.3 wt % As2O5).

Our results showed that local sources of phosphate, such as WWTP, in areas with elevated concentrations of As can significantly impact As behavior and may be responsible for elevated concentrations of As in surface waters.

Acknowledgments: This research was supported by the Grant Agency of Charles University (GAUK no. 790120), Czech Science Foundation (GAČR no. 22-27939S), and the Center for Geosphere Dynamics (UNCE/SCI/006).
Water supersaturation modeling for Early Mars Climate during Noachian
Authors: Delavois Antony , Forget François , Turbet Martin , Millour Ehouarn , Vandemeulebrouck Romain , Lange Lucas , Bierjon Antoine
Published: March 2022

Through today's observation of dry lakes, rives and large valley networks, we can assume liquid water abundantly flowed on Mars during the Noachian era, approximatively 4Gya. However, the climate that host this active water cycle is yet poorly understood. Recent modeling studies tried to reproduce the conditions that may have occured on the planet, trying to find an atmospheric process or composition that could solve the well known Faint Young Sun Paradox. Theses modeling studies, through the use of 3-dimensional Global Climate Models struggled to warm sufficiently the past climate of Mars, even considering different greenhouse gases, the role of clouds, meteoritic impact or even volcanism. However, the presence of H2 could be an interesting solution for a sustainable warming as some recent studies suggest (Turbet and Forget, 2021). Another recent study (Ito et al. 2020) suggested that H2O2 might be a convincing candidate but has to be in high supersaturation ratio in the atmosphere, even though it only used a simplified 1D model and relatively high supersaturation levels.

We try here to explore the scenario of supersaturated water, that might be a specy able to provide a sufficient global warming under supersaturated conditions or through the formation of high altitude clouds.  Through 1D and 3D modeling, we try to constrain the theoritical supersaturation level of H2O that will allow the warming of the climate above 273K. Our results suggest that in an atmosphere only composed of CO2 and H2O, water supersaturation can create a significant warming but only with with supersaturation levels in the lower layers of the atmosphere, although it can be seen as unrealistic. We describe in this work the effect of supersaturation on temperatures, clouds, and the water cycle of the simulated planet. Even if we do not tackle the question whether the supersaturation hypothesis is realistic or not, these results give a better understanding of what would be Early Mars' climate under such conditions.
Upscaling the impact of transport limitations in fluid-solid reactions using a chemical continuous time random walk
Authors: Aquino Tomas , Le Borgne Tanguy
Published: March 2022

Fluid-solid reactions play a key role in a wide range of biogeochemical processes. Transport limitations at the pore scale limit the amount of solute available for reaction, so that reaction rates measured under well-mixed conditions tend to strongly overestimate rates occurring in natural and engineered systems. Although different models have been proposed to capture this phenomenon, linking pore-scale structure, flow heterogeneity, and local reaction kinetics to upscaled effective kinetics remains a challenging problem.

We present a new theoretical framework to upscale these dynamics based on the chemical continuous time random walk framework. The approach is based on the concept of inter-reaction times, which incur delays compared to well-mixed conditions due to the times between contacts of transported reactants with the solid phase. We consider a simple chemical reaction in order to focus on the effects of transport limitations and medium structure, namely a second-order degradation reaction between a fluid-phase reactant and a solid-phase reactant distributed uniformly over the fluid-solid interface, where only the fluid reactant is consumed. Our formulation quantifies the global kinetics of fluid-reactant mass as it undergoes advection, diffusion, and reaction. Predictions are in agreement with numerical simulations of transport in stratified channel flows and Stokes flow through a beadpack. The theory captures the decrease of effective reaction rates compared to the well-mixed prediction with increasing Damköhler number due to transport limitations.
Micromagnetic modelling and single particle multipole expansions from Micromagnetic Tomography
Authors: Cortés‐Ortuño David , Fabian Karl , de Groot Lennart
Published: March 2022

Micromagnetic Tomography is a technique that combines X-ray micro tomography and scanning magnetometry data to obtain magnetic information of individual grains embedded in a sample. Recovering magnetic signals of individual grains in rock samples and synthetic samples provides a new pathway to study the rock-magnetic properties of remanent magnetizations that are crucial to paleomagnetic studies. This is possible by numerically inverting the surface magnetic signal for the magnetic potential of individual magnetic grains via their spherical harmonic expansion [1]. Resulting magnetic moment solutions are uniquely determined as dipole and higher order multipole moments, which has been proved in [2]. Furthermore, the higher order multipole signals in the magnetic particles are an indication that the grains carry complex magnetic orderings, such as multi-domain or vortex configurations [3]. In this work we show that the magnetic moment information can be used to constrain the internal magnetic configuration of individual grains using micromagnetic modelling. We first review the multipole expansion method used in Micromagnetic Tomography [3]. Further, we show three dimensional micromagnetic modelling results to predict the multipole signal of magnetic particles in different local energy minimum magnetization states. We show that for certain grains it is possible to uniquely infer the magnetic configuration from the inverted magnetic multipole moments. This result is crucial to discriminate single-domain particles from grains in more complex configurations. Our investigation proves the feasibility to select statistical ensembles of magnetic grains based on their magnetization states, which opens new possibilities to characterize stable paleomagnetic recorders in natural samples. 

[1] L. V. de Groot, K. Fabian, A. Béguin, M. E. Kosters, D. Cortés-Ortuño, R. R. Fu, C. M. L. Jansen, R. J. Harrison, T. van Leeuwen, A. Barnhoorn. Micromagnetic tomography for paleomagnetism and rock-magnetism. Journal of Geophysical Research: Solid Earth, 126:e2021JB022364, 2021.
[2] K. Fabian and L. V. de Groot. A uniqueness theorem for tomography-assisted potential-field inversion. Geophysical Journal International, 216(2):760–766, 2018.
[3] D. Cortés‐Ortuño, K. Fabian and L. V. De Groot. Single particle multipole expansions from Micromagnetic Tomography. Geochemistry, Geophysics, Geosystems, 22:e2021GC009663, 2021.