bluuebunny/crossref_metadata_2025 huggingface dataset:
Are all crystal-bearing magmas actually Newtonian?
Authors: Vasseur Jérémie , Wadsworth Fabian , Wayne Laurence , Dingwell Donald
Published: March 2022

Crystal bearing magmas have long been known to be non-Newtonian, exhibiting clear shear-thinning features when exposed to shear stresses. However, the micromechanical origin of this shear thinning remains enigmatic and attempts to describe how shear thinning arises in magmas have been equivocal. Here, we demonstrate that in controlled experimental systems, shear thinning is a non-local and scale-dependent artefact of crystal organisation during flow, and is not therefore an intrinsic property of the crystal-bearing magmas sensu stricto. Furthermore, we show that most experimental approaches to crystal-bearing magma rheology sit in a regime in which crystal migration effects will be dominant, explaining why the experimental evidence is that non-Newtonian effects are observed. We use a numerical conduit model for crystal migration physics to demonstrate that in nature, volcanic systems sit in another regime altogether and will not organise crystal cargo on the time- and length-scales of magma ascent. This leads us to tentatively conclude that crystal-bearing magmas on Earth are Newtonian, and that the only non-Newtonian effects of concern relate to bubbles at moderate capillary number, and the melt phase at moderate Weissenberg number. Finally, we note that this goes some way to unify the mismatch in effective viscosity between low-temperature analogue experiments and experiments on natural crystal-bearing melts.
Extensional faulting in the crests of growing anticlines – examples from seismic data and discrete-element modelling
Authors: Hundebøl Hansen Torsten , Rønø Clausen Ole , Lundsgaard Palmstrøm Esben , Damsgaard Anders
Published: March 2022

In contractional basin settings, the development of families of relatively small (throws = 10’s of meters) normal faults in the crests of growing anticlines is a common phenomenon. Various publications describe such faults from both outcrops, seismic data, analogue and computational models. The authors generally attribute their formation to local extensional stress fields arising from outer-arc extension in the bending sedimentary units or gravitational collapse. In spite of abundant reporting, crestal faults are rarely the focus of the given studies. An understanding of the phenomenon is relevant as these faults occur in many reservoirs in anticlines where they can affect compartmentalisation and fluid flow.

We present examples of crestal normal faults in the Danish sector of the North Sea that formed during folding associated with regional tectonic shortening and basin inversion. These faults display variations in structural style, which we link to differences in mechanical stratigraphy and geometries of the associated anticlines. Additionally, we present discrete-element models of crestal deformation during early anticline growth with various magnitudes of crestal-unit strengths and imposed lateral shortening. By analysing the results, we aim to identify the relative control of these parameters on the resulting structural style and strain distribution in the anticline crest.
Vertical and lateral variability of suspended sediment in cross-sections at the river Rhine
Authors: Slabon Aron , Hoffmann Thomas
Published: March 2022

Monitoring suspended sediment transported in fluvial systems is of major importance regarding natural hazards, water quality, and sustainable river management. However, monitoring is challenged by the spatial and temporal variability of suspended sediment transport and thus time consuming and costly. Here we analyze the spatial variability of suspended sediment in the German waterways using data from suspended monitoring networks of the German water and shipping authority (WSV). The data consists of four stations with cross-sectional measurements (isokinetic sampling with 20-25 samples/sampling campaign and 3-4 campaigns per cross-section/year) along with three stations with frequent (daily) point measurements. As the distribution of SSC with water depth is well established through the Rouse profile, uncertainties are induced through the determination of the settling velocity and the assumption of suspended sediment being transported as primary particles.

The lateral and vertical variability are quantified through the mean standard deviation for each vertical profile and sampling depth for each sampling campaign respectively. First, we investigate general patterns (including the vertical and lateral variability) of suspended sediment concentration (SSC) in the four different cross-sections. Second, we link the lateral and vertical variability with discharge, the magnitude of SSC, and flow velocity. Third, we estimate differences between the cross-sectional sampling and single point sampling.

Our preliminary results indicate an increase of vertical and lateral variability with average SSC in the cross-section. This involves a strong vertical gradient at high average SSC and increased variability at the bottom compared to near-surface SSC. As the flow velocity is smaller at the bottom, we detect a decrease in variability with higher flow velocity. These general patterns are present at each cross-section. However, site specific variations are abundant; caused by site specific properties, such as local morphology, lithology, and the impact of tributaries. Mean standard deviation of laterals and verticals shows the strongest connection to SSC, rather than discharge and flow velocity. Comparing cross-sectional average SSC with surface-sampling from the middle of the river ranges from strong underestimations (> 70 %) to strong overestimations (> 100 %) for single years with an average underestimation of approx. 11 % for all three stations over the 30-year sampling period used in this study. Thereby, incorporating cross-sectional measurements reduce uncertainties induced by point-sampling. Further, site specific adaptations regarding the sample location and an optimization of the sampling process utilizing simultaneous sampling could improve cross-sectional sampling.
Spatial distribution of the b-value in Southern California based on Gauss process inference with a geologically defined prior
Authors: von Specht Sebastian , Holschneider Matthias , Ferrat Khadidja , Zöller Gert , Molkenthin Christian , Hainzl Sebastian
Published: March 2022

As a population parameter, reliable estimation of the b-value is intrinsically complicated, particularly when spatial variability is considered. We approach this issue by treating the spatial b-value distribution as a non-stationary Gauss process for the underlying earthquake-realizing Poisson process. For Gauss process inference the covariance—which describes here the spatial correlation of the b-value—must be specified a priori. We base the covariance on the local fault structure, i.e. the covariance is anisotropic: elongated along the dominant fault strike and shortened when normal to the fault trace. This adaptive feature captures the geological structure better than an isotropic covariance or similarly defined and commonly used running-window estimates of the b-value.We demonstrate the Bayesian inference of the Gauss process b-value estimation for southern California based on the SCEDC earthquake catalog and with the covariance calibrated with the USGS fault model.Our model provides a continuous b-value estimate which reflects the local fault structure to a very high degree. Therefore, we are able to associate the b-value with the local seismicity distribution and can link it to the major Californian faults and geothermal areas. This technique, in its general formulation, can be applied to other non-stationary seismicity parameters, e.g. Omori’s law.
Structural and geochronological constraints on a Late Mesozoic extension event in the West Qinling Orogenic Belt, China
Authors: Zhang Le , Li Wei
Published: March 2022

The Qinling Orogenic Belt (QOB) has been well documented that it was formed by multiple steps of convergence and subsequent collision between the North China Block (NCB) and South China Block (SCB) during the Paleozoic and Late Triassic. Following the collision in the Late Triassic, the whole QOB evolved into an intracontinental orogeny. Large-scale N-S compressional and thrusting deformation tectonics along the previous major boundary faults were developed. Meanwhile, several extension-related tectonics were also developed in the QOB during or slightly later than the compression. However, the expiry date of the Late Mesozoic intracontinental compression orogeny and the tectonic transformation of the QOB remains unclear.

The extensional shear zone developed in the West QOB provides a crucial clue for revealing the orogenic belt's tectonic transformation and uplift and exhumation process. This paper focuses on kinematics, geochronology, and deformation temperature of the Taibai shear zone in the west QOB (TBSZ) to understand the intracontinental orogenic evolutionary process of the QOB.

The Taibai shear zone was developed at the northwestern margin of the Taibai pluton. It cuts across the QOB and separates the Taibai pluton in the east from the Baoji pluton in the west. The NE–NEE-striking and NW–NNW-dipping TBSZ is an extensional shear zone showing a top-to-the-NW sinistral shear sense. Mineral deformation characteristics and two-feldspar geothermometers constrain that the TBSZ was formed under the high greenschist–low amphibolite facies conditions (300-550 ℃) in the middle-upper crust (8-15 km). Zircon U-Pb dating and biotites and muscovites 40Ar-39Ar dating analysis suggest that the TBSZ was formed and uplifted rapidly during 120-113 Ma.

Combined with the regional geological data, the TBSZ records the extensional collapse of the Late Mesozoic intracontinental orogenic belt during the 120–113 Ma. The TBSZ also led to the rapid uplift and exhumation of the Taibai pluton and the North Qinling Belt in the east.
Thermo-chemo-mechanical coupling in Maxwell-Stefan multi-component diffusion
Authors: Khakimova Lyudmila , Moulas Evangelos , Utkin Ivan , Podladchikov Yury
Published: March 2022

Classical Fickian linear diffusion of inert or trace-like elements is restricted to ideal solution models of components with equal molar mass. Simultaneous diffusion of multiple concentrations is well-treated by the classical Maxwell-Stefan model. Quantitative predictions of concentrations evolution in real mixtures require careful replacement of concentration gradients by gradients of chemical potentials. Coupling of multi component diffusion to mechanics result in pressure gradients that contribute to Gibbs-Duhem relationship. We aim at developing of thermodynamically admissible multicomponent thermo-chemo-mechanical (TMC) model with ensured non-negative entropy production. We also ensure correct equilibrium limit with zero gradients of chemical potentials of individual components and satisfaction of classical Gibbs-Duhem and Maxwell relationships under pressure gradients. Following recent Tajčmanová et al. (2021) we consider both molar and mass formulations. We present optimal pseudo-transient numerical scheme for multi-diffusional fluxes coupled to visco-elastic bulk deformation.

Tajčmanová, L., Podladchikov, Y., Moulas, E. and L. Khakimova. The choice of a thermodynamic formulation dramatically affects modelled chemical zoning in minerals. Sci Rep 11, 18740 (2021).
Analysis of the environmental conditions favoring the development of deep pyroconvection in Southern Europe 
Authors: Senande-Rivera Martín , Insua-Costa Damián , Míguez-Macho Gonzalo
Published: March 2022

Deep pyroconvection can strongly modify surface weather conditions, especially when a firestorm develops, completely altering fire spread and making it more difficult to predict and control. However, the limited number of observations constrains our understanding of this type of events, so the environmental controls on deep pyroconvection are not entirely clear and, in particular, there are still uncertainties about the atmospheric conditions conducive to the development of this phenomenon. We conduct idealised numerical simulations with the fire-atmosphere coupled model WRF-Fire initialised with selected real-case atmospheric profiles of wind, temperature and moisture, obtained from the ERA5 database, corresponding to the 100 days of highest fire risk per year during the 2010-2019 period at six different European fire-prone locations. For each of these atmospheric profiles, we perform a suite of paired experiments of an ideal fire spreading through five different fuel categories. Each pair consists of a control run with interaction between fire and atmosphere and a simulation in which the sensible and latent heat fluxes from the fire are turned off (uncoupled simulation). This experiment allows us to make a significant statistical study of pyroconvection events and thus analyse which environmental factors favour its development. We found that a high fuel load, a large vertical temperature lapse rate between the 850 hPa and the 500 hPa levels and a high moisture content in the lower layers of the atmosphere are some of the main factors in the development of firestorms. 
A new Finite Elements Framework for Fjord-Iceshelf Interaction (FEFFII)
Authors: Ottolenghi Stefano , Wiskandt Jonathan , Ahlkrona Josefin
Published: March 2022

Modeling interactions between ice sheets and ocean has proved of significant importance in order to properly understand larger-scale phenomena such as ice sheet melting and ocean circulation. We introduce the Finite Elements Framework for Fjord-Iceshelf Interaction (FEFFII), a new simulation framework for fjord dynamics. Open source and Python-based, it employs the full non-hydrostatic Navier-Stokes equations to account for the ocean evolution, while ice shelf behavior is accounted by the 3-equations parametrization. Even though some its features are still under experimentation, FEFFII is already capable of simulating realistic scenarios and handling relatively complex geometries, as well as moving boundaries. The model has been tested against several benchmarks from literature.
The Mobility and Interaction of Poly(ethylene glycol) in Column Experiments with Cambisol
Authors: Kwarkye Nimo , Lehmann Elisabeth , Nischang Ivo , Vitz Jürgen , Schubert Ulrich , Ritschel Thomas , Totsche Kai
Published: March 2022

The transport of colloidal organic matter (OM) in soil is governed by colloidal hydrodynamics and frequently features strong interactions at the biogeochemical interfaces provided in the soil pore space. Conventional reactive tracers used to study solute transport usually fail to cover the hydrodynamics of small-sized colloidal OM. This impedes a clear observation of transport phenomena that are characteristic for these OM fractions. Tailor-made poly(ethylene glycol) (PEG) is available in a molar mass range featuring similar hydrodynamic sizes as colloidal OM. Thus, characterizing the transport of PEG could help to decipher the transport behavior of colloidal OM in soil.
We studied the transport of PEG in soil columns filled with homogenized Cambisol material. PEG was labelled with fluorophores to enable a highly resolved and sensitive detection via fluorescence spectroscopy. Parallel factor analysis (PARAFAC) was applied to the measured excitation-emission matrices to estimate the concentration of PEG in the column effluent. Additionally, batch experiments were conducted to determine the adsorption isotherms of PEG with the column substrate and typical soil minerals.
The resulting breakthrough of PEG was retarded by about an order of magnitude and with a pronounced tailing when compared to the breakthrough of non-reactive NaCl. The retardation points towards organo-mineral associations. This was corroborated by the adsorption observed in batch experiments with high maximum adsorption capacity with homogenized soil and clay minerals. The observed tailing may be due to the varying molecular dimensions of PEG contributing to kinetic interactions with soil minerals.
With representative hydrodynamics, varying molecular dimensions as colloidal OM and the possibility of forming organo-mineral associations with soil minerals, tailor-made PEGs are promising candidates to also follow the transport of other colloidal OM.
AMICal Sat, ATISE : From imagery to spectro-imagery for auroral studies
Authors: Barthelemy Mathieu , Kalegaev Vladimir , Robert Elisa
Published: March 2022

Space weather is a system science in the sense that it includes a chain of complex phenomena coming from the Sun and going to the Earth mainly through the magnetosphere. Added to this, the effects on the Earth infrastructures and their vulnerability should be taken into account. All this chain is too poorly described to allow accurate nowcasting and forecasting of the space weather events and of their effects on Earth. In this chain, the upper atmosphere as well as its interface with the magnetosphere require improvements in their description.

Precipitations of auroral electrons along magnetic lines lead to auroras, which are one of the most striking manifestations of space weather. These phenomena characterize the relationship of the magnetosphere and the upper atmosphere, and their intensity and localization indicate the state of near-Earth space. The energy release in the region of the auroral oval, associated with precipitation of auroral electrons, is controlled by the solar wind parameters and is one of the important reasons leading to changes in space weather in the polar magnetosphere and ionosphere.

In this frame, one of the main gaps in both data and modelling is the monitoring of the precipitation of low-energy (0.02 − 30keV ) particles in the ionosphere and in the magnetosphere, especially electrons which are key contributors to ionospheric currents.

Numerous satellites observed the polar lights both in the UV and visible, however AMICal Sat is the first cubesat to be dedicated to the observation of the optical emissions of the auroras. It contains a sparse RGB imager and has been launched on board the VV16 flight, September 3rd 2020. It will be followed by a spectrometer ATISE planned to be launched in 2023.

In this presentation, we propose to present the first results of AMICal Sat, the data processing to extract the intensity of each lines and thus deduce the electron fluxes. Plans for ATISE developments and ground based tests will also be detailed.
The updated multi-2D image of the gas accumulation zone inferred by seismic attributes and AVO analysis at the Solfatara Volcano, Italy
Authors: Gammaldi Sergio , Ismail Amir , Zollo Aldo
Published: March 2022

The imaging of volcanic structures by means of seismic techniques is aimed at the structural characterization and monitoring purposes. The quiescent volcano of the Solfatara belong to the caldera of the Campi Flegrei Italy, a resurgent nested caldera that has been extensively investigated through active seismic investigation.

The fumaroles of Bocca Grande and Bocca Nuova at the Solfatara volcano, represent some of the main markers of deep magmatic shallow hydrothermal activity. In this article we identify the gas accumulation zone using the attributes and scaled Poisson ratio extracted from multi-2D seismic profiles. The 400 m long profiles,  have been acquired during the active experiment RICEN (Repeated Induced Earthquake and Noise) performed in the context of the EU project MEDSUV between May and November 2014. The seismic arrays were deployed along the NE-SW and NW-SE directions within the crater across the zones of the fumaroles and the “fangaia”.

The time- and depth-sections are reconstructed after applying residual statics, DMO corrections, CMP gathering, and the post-stack Kirchhoff migration technique. The energy, root mean square, envelope, and sweetness attributes have been computed and extracted for determining the maximum and minimum values of amplitude zones on the migrated, post-stack seismic sections. Furthermore, we have investigated the time-gain attribute, which is used to interpret deep reflectors, and the variance attribute, that is a geometrical attribute providing information on location of faults, discontinuities, and chaotic zones. To better detail the reflectivity of shallow events, enhanced by the post stack attributes, the Amplitude Versus Offset (AVO) technique has also been used to discriminate and identify shallow gas pockets. The seismic profile, seismic attributes, and near-surface structural interpretation of the Solfatara volcano have been combined into a final structural image of the Solfatara subsoil. This show a clear evidence of the fluids trapping zones at 10-50 m depth beneath the crater's surface, as well as their migration paths down to 150 meters depth.
Modelling the reversibility of Pine Island Glacier
Authors: Reed Bradley , Gudmundsson Hilmar , Green Mattias , Jenkins Adrian
Published: March 2022

Pine Island Glacier (PIG), in West Antarctica, has undergone dramatic changes in the last few decades, where flow speeds have increased by 75% and grounding lines have retreated over 30km. These recent changes are part of a long term trend of mass loss, believed to have been initiated following climate anomalies in the 1940s and 1970s. The ice shelf cavity first opened around 1945, shortly after a strong El Niño event, and PIG eventually ungrounded from a submarine ridge in the early 1970s, following another notable warm period. Observational records show that intermittent periods of cooler ocean conditions likely slowed the subsequent retreat but were not enough to reverse its progress. 

 

Here we use the ice-flow model Úa to study the recent transient evolution of PIG over the last several decades with the aim of identifying the drivers of observed changes in geometry and grounding line position. We use a depth-dependent melt rate parameterisation driven by present day melt values to represent warm conditions, while experimenting with various cold parameterisations. We ask what happens when the model is forced with alternating periods of cool and warm conditions when PIG is grounded at the submarine ridge. We hypothesise that warm ocean conditions will force the ice stream off the ridge and cooler conditions will slow but not stop the retreat. This work will improve the understanding of how glaciers respond to short, intense warm intervals particularly as El Niño events become more frequent in a warming future. We present the results from the initial investigations into how PIG responds to ocean forcing using an ice flow model. 
Questioning the adequacy of an invasive plant management technique through remote sensing observations
Authors: Toussaint François , Alonso Alice , Javaux Mathieu
Published: March 2022

Palo Verde National Park, located in the northwest of Costa Rica, contains a wetland plain of international ecological importance in Central America. It is home of a rich biodiversity and provides vital shelter for over 60 species of migratory and resident birds.

From the 1980’s onward, the wetland landscape has shifted from diverse vegetation and large open water areas to a near monotypic stand of cattail (Typha domingensis). This resulted into a sharp reduction in the number of birds in the area, as many bird species prefer other native plants and open water for feeding, nesting and for shelter. The Fangueo technique, which consists in crushing the plant under water using a tractor equipped with angle-iron paddle wheels has been adopted to reduce the spread of Typha.

This plant management technique typically results in a significant decrease in Typha population in the first year after its implementation, as well as an increase in plant diversity and open water area.

In this study, we used historical Landsat and Sentinel imagery to investigate the medium to long-term impact of Fangueo on vegetation and open water. We found that invasive vegetation regrowth happened faster than previous studies had indicated. The increase in open water areas was therefore short-lived. This result questions the adequacy of this technique for invasive plant management.

This work highlights how crucial simple remote sensing methods can be for assessing the adequacy of supposedly effective environmental management practices, and for informing stakeholders.
An integrated assessment of multi-hazard events in Sweden
Authors: Mård Johanna , Bodin Örjan , Nohrstedt Daniel
Published: March 2022

Sweden is prone to various natural hazards, including wildfires, storms, floods, cloud bursts and landslides, which have caused considerable economic losses in the past. Natural hazard risk is also expected to increase in several regions in Sweden due to climate change. However, considerable knowledge gaps remain on how to effectively mitigate societal effects of multiple natural hazard events. Current risk assessments often focus on single hazards within distinct administrative boundaries whereas multi-hazard or compound events, which often transcend these boundaries, are rarely accounted for. This poses a problem – particularly in vulnerable geographical areas where the risk for compound events with significant societal impacts are high. Here we present a new project that will address this knowledge gap, with the aims to identify underlying factors of multi-hazard events in Sweden, and to investigate capacities among public and private actors to mitigate these impacts via effective collaboration. The first outcome is an integrated natural hazards assessment that reveals how climate-related natural hazard events have evolved over time and space in Sweden since the 1970s, and what areas have been most exposed to multi-hazard events. These results provide knowledge on the spatiotemporal distribution of natural hazard events, including compound events, which is critical when analysing their underlying drivers.
Monitoring the b-value unravels critical stress-changes along magma pathways: results from Etna volcano
Authors: Firetto Carlino Marco , Scarfì Luciano , Cannavò Flavio , Barberi Graziella , Patanè Domenico , Coltelli Mauro
Published: March 2022

The analysis of the b-value, i.e. the slope of the Gutenberg & Richter frequency-magnitude distribution of earthquakes, provides the chance to investigate the local stress conditions with great resolution, especially in active volcanic areas, where seismic productivity is generally high.

In this work we investigated the seismicity of Mt. Etna between 2005 and 2019, focusing on one of the largest known episodes of unrest in December 2018, when most of the intruding magma aborted its ascent inside the volcano. We found a possible stress concentration zone along magma pathways that may have inhibited the occurrence of a larger, more complete eruption. The b-values time series strongly increase about 19 days before the December 2018 unrest event, while a sharp drop of b started 2 days in advance. 

Our results suggest that the study of the b-value, in broader correlation with other monitoring measurements, may offer an opportunity to investigate the volcano state and improve the assessment of impending volcanic eruptions.
A multiscale approach for discovery of illegal micro-dumps based on satellite detections
Authors: Amitrano Donato , Angelino Cesario Vincenzo , Cicala Luca , Gargiulo Francesco , Gigante Gabriella , Nebula Francesco , Palumbo Roberto , Parrilli Sara , Pascarella Domenico , Pigliasco Gianpaolo , Tufano Francesco
Published: March 2022

Satellite remote sensing allows for large scale monitoring with low cost and high revisit time. However, in some applications, it does not provide all the information needed by the analyst for the full characterization of the problem due to, as an example, insufficient resolution or lack of specific measurements. This can lead to inaccuracies in classification and/or detection tasks. Nevertheless, satellite data can be used to guide subsequent discovery, recognition and characterization actions, defining potential areas of interest of limited extension that can be furtherly investigated with on-site strategies. This work presents an innovative framework showing how to use incomplete and inaccurate information extracted by satellite images in order to address on-ground discovery actions aimed to the mapping and the characterization of illegal micro-dumps in Campania Region (Italy). In particular, high-resolution images up to 50 cm resolution are exploited to detect potential micro-dumps by means of a statistical learning method based on spatial features. The detection map is then used to create a priority map based on environmental risk considerations, such as the extension of the area interested by the dump and its proximity to urban settlements, and previous risk mitigation actions. This information is ingested by a planning system in order to allocate and calculate patrolling routes based on the available manpower and vehicles for on-site surveying. The survey is implemented by means of drones equipped with payloads and software allowing for real-time three-dimensional reconstruction of the scene and volumetric estimations. This provides further data to assess the real dangerousness of the site giving to decision makers essential information to plan remediation actions. The system is demonstrated through a case study showing all the stages of the decision process.
Mantle contribution to surface heat flow of stable europe
Authors: Le Pourhiet Laetitia , Francois Thomas , Jolivet Laurent
Published: March 2022

Today, the European lithosphere is warm in average as attested by tomographic studies and many small volcanic centers located all over europe. This is of a prime interest for deep geothermal exploration to better understand the deep root of this effectively warm geothermal gradient in order to set better boundary conditions on fluid circulation models.

 

Volcanism is still “active” in the French massif central and Geophysical data show that the lithosphere is warm but they do not pinpoint, in Today’s mantle the signature of true mantle plume. Geological data show that the lithosphere might have been warm at least since Oligocene with the formation of the West European Rift system and the opening of the Gulf of Lion.

 

We have first set up thermo-mechanical models to test whether the interactions of global mantle flow with the base of the lithosphere and in particular the mantle root of the Pyrenées could generate viscous flow instabilities sufficient to locally erode the lithosphere of the French Massif Central and permit partial melting of the mantle. This first set of simulations have shown that this hypothesis is only consistent with 1/ an initially wet or thin European mantle lithosphere, with  2/ a relatively slow motion of the asthenosphere relative to the lithosphere (1 to 2cm/yr at most) which is more compatible with large scale mantle flow rather than slab retreat rates and 3/ a small component far field extension. The biggest constrain on our model is that we need the mantle upwelling to erode the base of the lithosphere and rise to approximately 70 km depth to produce melt.

 

This means that for the mantle to be hot Today, it must have been hot earlier than Oligocene.  This is not incompatible with the low temperature thermo-chronometers which suggest that the whole European platform was deeply eroded in presence of abnormally hot geothermal gradient while they show no global signature of the Oligocene event. We could keep it there but now we face a simple yet unanswered question. Simple thermal conductive model implies that in absence of tectonic events, like in the massif central or in Paris Basin, the thermal relaxation of the lithosphere should occur after 50 to 100Myr. Why is the western European lithosphere still warm today if the last global thermal event is co-eval with the opening of the Gulf of Biscay?  In other words, for modelers, what are the conditions to have a stable/steady state 100km thick lithosphere?  To answer that question, we added a deep mantle component to basal heat flow in the models.
Combined DInSAR-PSInSAR approach for increasing the quality of deformation map estimation in the area of underground mining exploitation
Authors: Wielgocka Natalia , Pawluszek-Filipiak Kamila , Ilieva Maya
Published: March 2022

Monitoring the deformation of the mining ground surface is crucial to ensuring the safety of residents, workers and the protection of all infrastructure in mining areas.The Polish realization of the European Plate Observing System project (EPOS-PL and its continuation EPOS-PL+) aims to build an infrastructure to monitor the deformation of the ground surface caused by extensive underground mining activities in the area of Upper Silesian Coal Basin in Southern Poland.  Among many geodetic and geophysical approaches for monitoring, two different Interferometric Synthetic Aperture Radar (InSAR) techniques have been applied, also taking the advantage of the big set of freely available and with shorter revisiting time (6 days) Sentinel-1 satellite data. In the current study the Differential InSAR (DInSAR) and the Persistent Scattered Interferometry (PSInSAR) approaches are compared, evaluated and integrated. Various processing strategies are tested aiming to increase the quality of the produced integrated deformation maps. The optimal processing strategy should accurately detect stable areas, estimate the small deformation, as well as the maximum deformation gradient occurring in the center of the subsidence bowl directly in the excavation area. 

One of the main error contributors to the Sentinel-1 data is the water vapor in the atmosphere that might slower the radar signal and modulate the results. Thus, the atmospheric artefacts have to be minimized since they are one of the main effects that limits the accuracy of interferometric products. In the PSInSAR approach high-pass and low-pass filtering has been used, while in the DInSAR approach – estimation of the Atmospheric Phase Screen has been made based on polynomial surface estimation using stable coherent points. Comparison of the one-year cumulated deformation for the area of Rydułtowy mine in Poland with ground truth data such as static GNSS measurement on reference points shows that PSInSAR results are more accurate. However, due to the linear deformation model required in the PSInSAR processing the areas in the center of the subsidence bowls were not estimated. Therefore, the difference between PSInSAR and DInSAR results was used for the refinement of the DInSAR deformation map. This refinement was made based on various statistical approaches (e.g. polynomial interpolation, kriging, inverse distance weighted-IDW). The results of IDW and kriging shows the best performance and allowed to minimize errors associated with DInSAR approach and provide a more accurate deformation map in the area of mining as well as provided the opportunity to capture maximal deformation gradient. 
Characteristics of extremely warm and extremely cold events in Iceland – The Couch Diagramme
Authors: Mollard Guilhem , Ólafsson Haraldur
Published: March 2022

Temperature extremes are in general relatively difficult to forecast accurately and it is important to assess their nature and characteristics, both in numerical models and in reality.  Such extremes in Iceland have been explored and linked to two key parameters of the flow; low-level wind speed and static stability.  The results reveal very distinct distribution of cases in the space of these parameters:  Cold extremes in the winter occur only at low wind speeds, while in the summer, they occur only in low static stability.  Warm extremes in the winter occur on the other hand only at high static stability, and warm extremes in the summer occur only at low wind speeds.  This result can be summarized in The Couch Diagramme.
Temporal and spatial effects of elevated CO2 on greenhouse gas fluxes from tree stems in an upland temperate forest
Authors: Barba Josep , Curioni Giulio , Gauci Vincent
Published: March 2022

Tree stems emit CO2 and can exchange CH4 with the atmosphere (either emitting or uptaking), with a significant contribution to the C budgets from local to regional scales. However, there is still a need to better understand the spatial and temporal variability of stem CO2 and CH4 fluxes to quantify the role of vegetation on the C cycle and how these fluxes will behave under future environmental conditions such as atmospheric elevated CO2. An increment of atmospheric CO2 concentrations might result in higher photosynthetic rates, which would spin the C cycle in the trees, potentially increasing stem CO2 emissions due to higher stem respiration and higher soil-derived CO2 contribution. Higher photosynthetic rates might also stimulate fine roots exudation, which could stimulate methanotrophic or methanogenic communities. Additionally, elevated CO2 would increase water use efficiency at the leaf level, reducing the amount of water transpired, and potentially increasing soil moisture, which would favour conditions for CH4 production. In this study, we present one year of monthly measurements of stem CO2 and CH4 fluxes from mature oaks (Quercus robur) growing under elevated CO2 (~150 ppm above atmospheric concentrations) and ambient conditions, in a second-generation FACE experiment (Free Air CO2 Enrichment; BIFoR-FACE UK). Trees growing under ambient conditions emitted 76% more CO2 than those under elevated atmospheric CO2, which was not what we hypothesized. Despite stem CH4 fluxes have been reported in multiple upland ecosystems for lots of tree species, our preliminary results did not show clear evidence of CH4 stem fluxes (emissions or uptake) for the oaks at our study site. Similar measurements in other FACE experiments are needed to determine if our results on the effect of elevated CO2 on stem CO2 and CH4 fluxes could be extrapolated to other ecosystems and species. 
Morphological parameters to assess the state of coastal dunes
Authors: Bon de Sousa Luisa , Costas Susana , Ferreira Óscar
Published: March 2022

Coastal dunes host priority habitats that provide different ecosystem services, such as biodiversity or socio-economical resources, and they are the first line of defence against the impact of storms, providing protection to adjacent coastal communities. However, the capacity of these systems to provide such services depends on their morphological and ecological status, which may change spatially and over time. Despite the relevance of assessing to dune state, a simplified and universal approach for this purpose is lacking. The present work explores the temporal and spatial variability of a series of morphological parameters and their best combination to inform about the state and resilience of coastal dunes. For that, the morphology of one sandy peninsula and one barrier island, with contrasting exposure to meteocean conditions and anthropogenic pressure, located within the Ria Formosa in the south coast of Portugal, were analysed. The available dataset covers the period between 2008 and 2018 and consists of Digital Terrain Models (DTMs) and orthophoto mosaics. Shoreline indicators (e.g., wet/dry line, debris line, vegetation seaward limit and dune heel line) were mapped in all orthophoto mosaics and extracted each 10 m alongshore. Parallelly, cross-shore profiles were defined at each 10 m from the DTMs to automatically extract the position and the elevation of the dune crest, dune toe and berm. The extracted parameters and indicators allowed estimating the width and slope of the different segments within the beach and the dune. Results show significant differences in the dune crest height alongshore each barrier while other parameters such as the dune toe presented a rather intra-barrier homogeneous distribution intra-system. The latter parameters are significantly different from barrier to barrier while the dune crest height values partially overlapped when both barriers were compared. Observed temporal and spatial variability of the extracted parameters was tentatively compared with the historical evolution of the evaluated barrier and the incident wind and wave conditions suggesting that the parameters might be regulated by different drivers. For instance, while the dune crest height appears strongly regulated by the historical evolution of the coast, the rest of the parameters, homogeneous within each barrier, appear to be controlled by external factors associated to the variable orientation of the coast relative to the main wave and wind climate. These results might be highly relevant when assessing the adaptation capacity of these type of systems and thus to their resilience with implications on the definition of coastal barrier states and tipping points in barrier response to disturbances.
Understanding better the environmental and landscape impacts of drought on the Horn of Africa Drylands
Authors: Limones Natalia , Wens Marthe , Odongo Rhoda , Van Loon Anne , De Moel Hans
Published: March 2022

Droughts cause major impacts on the Horn of Africa Drylands (HAD), but the factors that determine the magnitude of these impacts are not well understood. The focus is mostly on socio-economic impacts, but environmental and landscape impacts are often overlooked, in part because they are not always immediate, or their direct or indirect linkage to drought is not apparent. However, drought-induced natural resources and landscape degradation can hinder agricultural activities, livestock farming, tourism, etc., causing socio-economic problems as well. Therefore, it is important to study environmental drought risk and its drivers.

In this research, we adopt a machine learning approach to estimate the chance of experiencing environmental and landscape impacts, specifically: degradation or loss of vegetation cover, significant land-use changes, increased number and severity of fires and poor air quality events related to dust concentration, in Ethiopia, Kenya and Somalia. We will use fast and frugal trees to link accumulated water deficits, calculated using several meteorological and hydrological drought indices, with observational data on past drought impacts on the landscape and the environment. Impacts are detected with high-resolution remote sensing imagery products (Copernicus Global Land Cover Layers, WAPOR, Sentinel-5P NRTI AER AI and several MODIS products, among others), which have the advantage of providing continuous long-term information at large scales.

The applied supervised machine learning approach objectively selects drought hazard indices (including their time and severity thresholds) with the best predictability for observed impacts, capturing the relationships between hazard indices and impacts in the HAD administrative divisions. This modelling approach allows for the identification of region-specific issues while it guarantees comparability. This makes it particularly useful for this case study, as the studied environmental and landscape impacts may be context- or location-specific and could arise from a mixture of different drought types.

The method aims at understanding if, when and how environmental and landscape impacts occur simultaneously or successively and allows us to uncover their interlinkages with each other and with the different drought types.
Generation of fine structures in interplanetary type III radio bursts induced by density inhomogeneities in the ambient plasma
Authors: Jebaraj Immanuel Christopher , Magdalenic Jasmina , Krasnoselskikh Vladimir , Poedts Stefaan
Published: March 2022

Solar radio bursts have been studied for over 60 years, however some aspects of their generation and propagation remain to be open questions to the present day. It is generally accepted that majority of solar radio bursts observed in the corona is via the coherent plasma emission mechanism, and a substantial amount of work has been done to support this idea. Fine structures in solar radio bursts can therefore provide important input for understanding the background plasma characteristics.  The presently available advanced ground-based radio imaging spectroscopic techniques (using e.g. LOFAR, MWA, etc.,) and space-based observations (Wind, STEREO A & B, Parker solar probe, Solar Orbiter) provide a unique opportunity to identify, and study fine structures observed in the low corona and interplanetary space.

In this study, we focus on the radio fine structures observed in range of the hecto-kilometric wavelengths that were much less studied than the one in the metric-decametric range. We present for the first time three different types of fine structures observed in interplanetary type III radio bursts (radio signatures of fast electron beams propagating via open and quasi-open magnetic field lines). The presented fine structures show spectral characteristics similar to the striae-like fine structures observed within the type IIIb radio bursts at decametric wavelengths. We employ the probabilistic model for beam-plasma interaction to investigate the role of density inhomogeneities on the generation of the striae elements. The results suggest that there is a good correlation between the width of the striae elements and the scale of density inhomogeneities found in interplanetary space.
Climate-justified strategies for sustainable urban water supply system: sources diversification in Almaty city, Kazakhstan
Authors: Torabi Haghighi Ali , Baubekova Aziza , Xenarios Stefanos
Published: March 2022

Kazakhstan is a country in transition experiencing a rapid urbanization process with the highest rate in Almaty, the former capital of the country and the largest metropolis in the whole region. Over the past ten years, the city area has doubled its size. Being a concentration of economic and political power, Almaty attracts people from rural areas and neighboring states. Uncontrolled migration of the population leads to disproportional development of the city with inequality between the center and the periphery of the city. Rapid economic development and city growth led to increased per-capita water use and overall water demand and put pressure on water infrastructure. Such the foothill areas of Almaty, the southern part of the Nauryzbay, Bostandyk, and Medeu districts are experiencing a shortage of water supply due to low productivity, deterioration, or absence of networks and facilities. The city is located at the foothills of the northern Tien Shan Mountains in the valley of 4 rivers: Big and Small Almatinka, Esentay, and Kargaly. Climate change led to severe changes in Central Asia at high altitudes, including two times higher than the global average temperature rise and rapid glacier retreat. Shrinking glaciers supply ample quantities of water in the form of increased glacial runoff, and reduced glacier volume will ultimately result in a decrease in both glacier-fed and total runoff. There is no reduction in streamflow in any catchment or season in the northern Tien Shan. Instead, there is a positive trend in surface water availability.  At the same time, climate change poses the risk of more prolonged recharge of reservoirs and aquifers and may cause exhaustion of this water source that currently provides 70% of water for the city. Therefore, envisioning a long-term sustainable development perspective for a city, water resource efficiency, and climate change adaptation should be addressed together. Thus, our study suggests for the short term to limit the use of strategic groundwater reserves and diversify the water supply sources with a bigger share of surface water to benefit from the melting glacials. If the water allocation from groundwater reservoirs will be reduced and the aquifers will be recharged the water deficit for the city may be postponed.