bluuebunny/crossref_metadata_2025 huggingface dataset:
New constraints on the kinematics of the western Sinai Microplate: geodynamic implications 
Authors: Granot Roi , Katz Oded , Kanari Mor , Hyams Orit , Hamiel Yariv
Published: March 2022

The tectonic nature of the Sinai Microplate's western boundary is clouded with uncertainties. Early studies suggested that the western edge of Sinai is fully connected to the African Plate, thus concluding that Sinai is a sub-plate. Later, bathymetric analyses of prominent lineated faults straddling across the western edge of the Levant Basin have suggested that, in fact, this area is a plate boundary that accommodates dextral motion between the African Plate and the Sinai Microplate. However, this inference contradicts geological and geophysical observations across the Gulf of Suez, the southern continuation of the same plate boundary. Here we present preliminary results from a recent geophysical cruise aboard the R/V Bat Galim. We focused our investigation on one of the major faults, oriented in an NW-SE direction (located ~80 km southwest of the Eratosthenes Seamount), creating the plate boundary. We collected high-resolution shallow multichannel seismic reflection data complemented with multibeam bathymetry data. We also acquired two piston cores near the trace of the fault. These observations unravel the shallow three-dimensional structure of the fault system whereby several curved and steeply dipping normal fault segments are splayed from the main fault trace in a westerly direction. These secondary faults display a back-tilted and step-like morphology. This structure is best explained by a sinistral motion acting along the master fault. Independently, we present an updated Africa-Sinai Euler pole based on the motion of GPS stations recorded between 1996 and 2019. The results suggest that Sinai is moving in a northwesterly direction with respect to Africa (1.7-1.9±0.9 mm/yr). Focal mechanism solutions calculated for recent earthquakes occurring in this region (Mw>4.5) agree with the geodetic constraints of a sinistral relative motion.

Overall, these observations suggest that the western boundary of Sinai has been, and still is, accommodated sinistral motion relative to Africa. This conclusion implies that the Sinai Microplate is moving faster with respect to Eurasia relative to the motion of Africa with respect to Eurasia. This, in turn, seems to be in conflict with the notion that subduction of the oceanic lithosphere north of the Sinai Microplate (i.e., east of Cyprus) has recently ceased. We speculate that the downgoing slab might still promote the relatively fast northward motion of Sinai and/or a northward drag force induced by large-scale mantle flow related to the Afar plume could also contribute to the motion of the Sinai Microplate.
Eliciting public preferences for wildfire management policies in Crete, Greece
Authors: Misal Haleema , Kountouris Ioannis , Voulgarakis Apostolos , Rovithakis Anastasios
Published: March 2022

Fire regimes form an integral part of terrestrial biomes in the Mediterranean region as they provide essential disturbances which change the structure and function of plants that favour Mediterranean type climates. Fire is inextricably linked to such ecosystems and cannot be excluded from them. However, the intensification of human activities in Greece, coupled with increasingly unpredictable wildfires has created huge imbalances and jeopardised the ecological integrity of ecosystems. Expansions into the wildland urban interface, rural abandonment, and the focus on fire suppression are increasing the vulnerability and flammability of the Greek environment. The duality of fire is delicate, both at local and national level, catastrophic wildfires singe deeply on landscapes and economies, social burns can take just as long to heal. In Greece, this is further exacerbated by the burgeoning socio-economic and political complexities that have catalysed the current ineffective and unsustainable fire management strategies. Damages from wildfires affect ecosystem services which can lead to a reduction in human wellbeing. Understanding the interactions between ecosystems and humans through environmental valuation is key to implementing effective policy. This study uses economic valuation methods in the form of a choice experiment to elicit public preference for a wildfire management policy in Crete. A survey was deployed around the island, with respondents asked about their preferences between different management strategies. The policies outlined in the survey are made up of the following attributes: risk of fire, agricultural production, landscape quality and post-wildfire damage mitigation. Results from this study indicate a positive preference by the public for a new proposed policy. The findings from this study can be used for decision making in Crete and other similar southern European environments by providing metrics for appropriate wildfire management.
Predicting Patagonian Landslides: Roles of Forest Cover and Wind Speed
Authors: Parra Hormazábal Eric , Mohr Christian , Korup Oliver
Published: March 2022

Many of Earth's steepest, wettest, and rapidly denuding landscapes are covered by dense temperate rainforests. Chilean Patagonia hosts some of Earth's largest swaths of temperate rainforests where landslides frequently strip hillslopes of soils, rock, and biomass.

The susceptibility to shallow landslides can increase following deforestation because of limited root reinforcement, altered soil infiltration, and permeability rates. The wind is a common driver of forest disturbance. While anchoring soils, trees also transfer dynamic-wind force as a turning moment (torque) to the soil mantle via the tree bole, causing tree throw or even shallow slope failure. Despite the above, inquiries into the role of wind in landslide initiation have been anecdotal and unclear about cause and effect.

Assuming that wind loads on trees cause slope instability, we explore the role of forest cover and wind disturbances in promoting such landslides using a hierarchical Bayesian logistic regression model that predicts from crown openness and wind speed the probability of detecting landslides terrain. To control for effects of local terrain steepness, our multi-level model admits different landform types such as channels, ridges, or valley floors.

We find that higher crown openness and wind speeds credibly predict higher probabilities of detecting landslides regardless of topographic location, though much better in low-order channels and on midslope locations than on open slopes. Wind speed has less predictive power in areas that were impacted by tephra fall from recent volcanic eruptions, while the influence of forest cover in terms of crown openness remains.

Distinguishing between landforms in a hierarchical model context improves an otherwise moderate average performance of the classification, but highlights topographic locations for which the prediction needs to be refined.

Our study is the first of its kind in one of the windiest spots on Earth and encourages further inquiry into the rarely investigated role of wind speed in promoting slope instability in southern Chile and densely forested mountain regions elsewhere, especially with weather and wind extremes being on a projected rise in a warming world.
Continuation and Damping of Zonal Flows by Stably Stratified layers
Authors: Dietrich Wieland , Wulff Paula , Christensen Ulrich R.
Published: March 2022

Geostrophic zonal flows appear naturally in rapidly rotating, convective systems that resemble the convective atmospheres of giant planets. However, the depth of the flows is potentially limited by stratified layers inhibiting convection. Here we study the continuation and damping of zonal flows across the interface and into such a stratified layer. In order to analyse the problem in a systematic way, we validate cartesian and analytical models by using spherical shell models with enforced axisymmetry. Compared to full 3D models they provide the advantage of being much less computationally demanding and producing plentiful jets within the shell's tangent cylinder.

The analytical model predicts that for weaker stratification, the damping of the jets in the stable layer follows the prediction of the classic linear theory of penetrative convection and thus scales with the length scale of the jets and the relative stratification ($N/\Omega$, where $N$ is the Brunt-V\"{a}is\"{a}l\"{a} frequency and $\Omega$ the rotation rate). However, for strong stratifications, characteristic for compositional gradients (eg. He-rain), the damping rate becomes independent of $N/\Omega$ and is solely controlled by the jet width. The axisymmetric spherical shell simulations verify this prediction over a wide range of parameters. These results yield also important consequences for modelling the wind-induced gravity field anomalies of Gas Giants.
Short-term regeneration dynamics after windstorm: the study case of Vaia storm. 
Authors: Marangon Davide , Betetto Claudio , Lingua Emanuele
Published: March 2022

Mountain forests are complex ecosystems with a delicate equilibrium, providing several important ecosystem services (ES). Natural disturbances are the most important factor influencing mountain forest dynamics, and shaping forest stands. Under the current climate change (CC) scenarios, disturbance regime is changing, and new types of disturbances affect forest ecosystem. Nevertheless, to restore or maintain the provisioning of important ES, it is crucial to find the most effective post-disturbance management strategy in these new conditions. There are three different logging strategies generally applied in windthrown stands: salvage logging (SL), no intervention (NI), or partial salvage logging (PSL). To restore forest cover as soon as possible is the main goal in post-disturbance management. Understanding natural regeneration dynamics and their interaction with the logging interventions is therefore crucial to correctly implement forest restoration activities.

In this study, we analyzed the post-disturbance regeneration dynamics in 25 areas damaged by the biggest windstorm of the last century in the southern Alps, called Vaia, that hit northeast Italian Alps in 2018. We collected data from all over Veneto region, which was heavily damaged by the storm. The aim was to analyze how natural regeneration density and diversity are influenced by different logging systems (cable-based, ground-based, mixed system); how the distance from windthrow edges influence seedling establishment; and how the environmental conditions (e.g. exposure, slope, elevation, etc..) influenced regeneration dynamics. Pre-storm regeneration represents an important starting point to restore forest cover. We analyzed its contribution to regeneration dynamics, in relation to different logging systems and different soil cover within the gaps.

In this contribution, the sampling methodology will be presented and the preliminary results discussed.
Comparative Evaluation of OTT-Parsivel2 Measurements for Raindrop Fall Speed Using a Collocated High-speed Optical Disdrometer (HOD)
Authors: Testik Firat , Saha Rupayan
Published: March 2022

This study evaluates OTT Parsivel2 raindrop fall speed measurements using measurements from a collocated High-speed Optical Disdrometer (HOD).  Raindrop fall speed is an important quantity for calculating precipitation parameters such as raindrop kinetic energy and size distribution that are critical for various hydrological and meteorological applications.  In relevant applications, raindrop fall speed has often assumed to be terminal that is typically predicted by using terminal speed – raindrop size relationships obtained from laboratory observations.  Nevertheless, recent field studies have shown deviations of raindrop fall speed observations from the predicted terminal speeds; and hence, highlighted the importance of observational raindrop fall speed information.  Considering the large userbase of OTT Parsivel2, this study assesses the raindrop fall speed measurements of this instrument with respect to the HOD measurements during rainfall events with a range of rainfall intensities.  The results of this investigation with potential implications will be discussed in this presentation.  This material is based upon work supported by the National Science Foundation under Grants No. AGS-1741250.
Interplay between subsurface eddies and sea ice over the Arctic Ocean
Authors: Cassianides Angelina , Lique Camille , Treguier Anne Marie , Meneghello Gianluca , Demarez Charly
Published: March 2022

The paucity of observations over the Arctic Ocean prevents us from fully understanding the interaction between sea ice and mesoscale dynamics. Previous studies on this interplay have documented the interaction between surface eddies and sea ice, omitting the subsurface eddies. This work focuses on the possible role of these subsurface eddies in shaping the sea ice distribution. First, we perform an extensive eddy census over the period 2004-2020 over the Arctic Basin, based on data from Ice Tethered Profilers (ITP) and moorings from the Beaufort Gyre Exploration Project. About 500 subsurface eddies are detected, including both submesoscale (radius between 2-10 km) and mesoscale (up to 80 km) structures. Second, we investigate the dynamical or thermodynamical signature that these eddies may imprint at the surface. On average, these eddies do not cause significant variations in either the temperature of the mixed layer or the melting of sea ice. However, we estimate that subsurface eddies induce a dynamic height anomaly of the order of a few centimetres, leading to a surface vorticity anomaly of O(10^{-5} - 10^{-4}) s^{-1}, suggesting that they may be a significant local forcing for the sea ice momentum balance. Our results suggest that there is no link between the sea ice evolution and the energy level associated with the presence of subsurface eddies. It suggests that once formed, these structures may evolve at depth independently of the presence of sea ice. 
Seismic attenuation tomography in the Carpathian-Pannonian region from ambient seismic noise analysis
Authors: Borleanu Felix , Petrescu Laura , Magrini Fabrizio , Placinta Anica Otilia , Grecu Bogdan , Radulian Mircea , De Siena Luca
Published: March 2022

The Carpathian-Pannonian region (CPR) is one of the geotectonically most exciting areas of Europe due to a diversity of tectonic processes activating in close proximity: extensional basin evolution, oceanic subduction, post-collisional volcanism, as well as active crustal deformation associated with the push of the Adria plate or the pull of the actively detaching Vrancea slab. This makes CPR an excellent natural laboratory to study the behavior of the lithosphere-asthenosphere system in a special tectonic setting. To emphasize the lateral heterogeneity and physical properties of the crust in the CPR we investigate noise data recorded by the vertical components of broadband stations that have been operational in 2007, 2009, 2010, 2011 and 2020 in Eastern Europe, kindly provided by the Romanian Seismic Network and EIDA-European Integrated Data Archive. With the advent of this large amount of data and by applying a new processing method of ambient seismic noise field based on the continuous wavelet transform, we computed cross-correlations between various station pairs to transform every available seismic station into a virtual source. The inter-station cross-correlograms were used to determine the coda quality factors (Qc) in three different period ranges (2.5–5 s, 5–10 s and 10–20 s) and invert them using a modified version of the open-access code MURAT2D to construct the highest resolution attenuation tomography of the region. By mapping the attenuation features, within the study region, our results reveal high attenuation features throughout the Bohemian Massif, Alcapa unit, and Vrancea area, as well as a strong difference in attenuation between the Pannonian Basin, and stable platform regions located in front of the Carpathians. In addition, Qc variations are larger at short period in agreement with the strong heterogeneities in the uppermost crust. Finally, our findings demonstrate that noise correlation approaches are more efficient in analyzing Qc at lower frequencies than those previously proposed for earthquake data analyses.
Extreme event waves in marine ecosystems: method and application to the surface chlorophyll in Mediterranean Sea
Authors: Di Biagio Valeria , Cossarini Gianpiero , Salon Stefano , Solidoro Cosimo
Published: March 2022

Extreme events can have great impacts on the functioning of marine ecosystems. In this work we describe a novel method that identifies and characterises extreme events in marine ecosystems at the basin scale, by accounting for the persistence of the events within a certain impacted area and over a specific time duration. Extreme events are firstly identified as peaks over a predefined threshold (i.e. the 99th percentile) computed from a local timeseries. Then, a series of extreme events that are connected over space and time is defined as an extreme event wave (EEW) and characterised by a set of indexes describing their initiation, extent, duration and strength.  
We applied the method to surface chlorophyll concentration, that is an essential ocean variable representative of the marine ecosystem state and evolution. Since high frequency and seamless data in time and space are mandatory to properly detect extreme events on the basin scale, we used daily data provided by a numerical model. In particular, we employed data of winter-spring surface chlorophyll concentration provided by the coupled hydrodynamic-biogeochemical model MITgcm-BFM at 1/12° horizontal resolution, validated in the Mediterranean Sea in the 1994-2012 period. Our method allowed us to identify and characterise surface chlorophyll EEWs occurring in the considered period and also to provide a bio-regionalisation of the Mediterranean Sea associated to different regimes of chlorophyll dynamics, by means of a fuzzy classification of EEW indexes.
Characterization of Fluid Connectivity in Sedimentary Sequences using Strontium Isotopes
Authors: Johansen Ingar , Polteau Stephane , Schöpke Christian Alexander
Published: March 2022

Characterization of Fluid Connectivity in Sedimentary Sequences using Strontium Isotopes

 

Johansen1 I., Polteau1 S., Schöpke1 C.A.

 

Institute for Energy Technology (IFE), Instituttveien 18, 2007 Kjeller, Norway, stephane.polteau@ife.no

 

Sedimentary basins typically contain complex internal heterogeneities that can segregate fluids into a series of isolated compartments. The permeability of these heterogeneities is often dynamic and time dependent: they can form impermeable barriers that prevent porous flow in timescales of a few years, while allow mixing of fluids by advection and/or diffusion on geological timescales. In general, the isotope composition of formation waters forms trends reflecting mixing by advection or slow equilibration controlled by diffusion during isotope exchange. In nature, when two systems (rocks, minerals, water/rock mixtures) are in chemical equilibrium but have different isotope compositions, both systems exchange their atoms to tend towards isotopic homogeneity while being chemically heterogeneous. Hence, the trends in isotope data enable the identification of a dynamic residual signal that would otherwise not be noticeable by other data that equilibrate faster. For example, pressure differences between sedimentary units equilibrate rapidly within a few thousand years, while millions of years are necessary to homogenize the isotopic composition of formation waters across low-permeability boundaries. Interpretation of these geochemical patterns provides information about the flow properties of the system and help to predict fluid connectivity and migration between different units. As such, Strontium Residual Salt Analysis (SrRSA) can help pinpoint important flow barriers and identify fluid connectivity in sedimentary basins.
Drained lake basins on a circumpolar scale – Updates from the IPA Action Group
Authors: Bergstedt Helena , Jones Benjamin , Grosse Guido , Veremeeva Alexandra , Breen Amy , Liljedahl Anna , Bartsch Annett , Gaglioti Benjamin , Bouchard Frédéric , Hugelius Gustaf , Nitze Ingmar , Wolter Juliane , Hinkel Kenneth , Farquharson Louise , Fuchs Matthias , Kanevskyi Mikhail , Roy-Leveillee Pascale , Lantz Trevor
Published: March 2022

Lakes and drained lake basins (DLB) are ubiquitous landforms in permafrost regions. The long-term dynamics of lake formation and drainage is evident in the abundance of DLBs covering 50% to 75% of arctic permafrost lowlands in parts of arctic Alaska, Russia, and Canada. Following partial or complete drainage events, DLBs evolve through time. As the basins age and ground ice enrichment occurs, the surface heaves and vegetation communities evolve, exhibiting spectral and texture differences indicative of these changing conditions. This mosaic of vegetative and geomorphic succession and the distinct differences between DLBs and surrounding areas can be discriminated and used to make a landscape-scale classification employing various indices derived from multispectral remote sensing imagery that, when combined with field sampling and peat initiation timing, can be used to scale across spatial and temporal domains. Previously published local and regional studies have demonstrated the importance of DLBs regarding carbon storage, greenhouse gas and nutrient fluxes, hydrology, geomorphology, and habitat availability. A coordinated pan-Arctic scale effort is needed to better understand the importance of DLBs in circumpolar permafrost-regions. Here we present an update of ongoing work within the Action Group on DLBs supported by the International Permafrost Association (IPA), an effort by the community to develop a first pan-Arctic drained lake basin data product. Comprehensive mapping of DLB areas across the circumpolar permafrost landscape will allow for future utilization of these data in pan-Arctic models and greatly enhance our understanding of DLBs in the context of permafrost landscapes. Utilizing remote sensing imagery (Landsat-8) and freely available DEM data sets (e.g. ArcticDEM) allows us to implement our mapping approach on a circumpolar scale. A previously published prototype of this data product covering the North Slope of Alaska forms the basis of this large-scale mapping effort. Here we present first result working towards a pan-Arctic remote sensing-based DLB data product focussing on selected areas in Canada and Siberia, Russia.
Green Sahara spatial and temporal patterns
Authors: Claussen Martin , Dallmeyer Anne , Duque Villegas Mateo , Jungandreas Leonore
Published: March 2022

Social, biological and environmental dynamics have affected the way of humans out of Africa during the late Quaternary. Hence understanding the dynamics of these three factors and their interaction is a prerequisite for understanding human migration. Conceptual climate and environmental modeling is often based on individual paleo climate records which are sparsely distributed in space and time, and fewer and fewer records exist the further one looks into the past. Can climate system modeling provide a way forward? So far, different climate system models yield completely different patterns of past greening in the Sahara. None of the global models is able to generate local landscape changes like the emergence of gallery forests or wetlands that could provide green corridors or barriers for migration. Considering a spectrum of models of different complexity might be the way forward. Coarse-scale models can be used to explore multi-millennial-scale and continent-scale dynamics, thereby providing information on the large-scale effect of orbital forcing or the gross differences in the overall dynamics of the last African Humid Periods, for example. Global climate system models with a grid size of some 100 km, e.g. the CMIP models, yield interesting insight into large-scale atmospheric dynamics and regional heterogeneity, like differences between West and East Sahara weather and vegetation patterns. This type of models can also help reconciling seemingly divergent reconstructions, such as the discussion of abrupt vs gradual termination of Saharan greening some 5000 years ago. For a more detailed view on local landscape changes, regional climate models operating at km-scale are necessary to resolve the complex orography, mesoscale convection and related local climate changes. These models can currently be run over seasons only. However, development of a new generation of Earth system models bodes well for the potential use of global high-resolution simulations. In summary, we suppose that using the spectrum of climate system models will bring models and proxy data closer together and will advance our understanding of past climate change and human migration.
Zonal Winds in the Gas Planets Driven by Convection above a Stably Stratified Layer
Authors: Wulff Paula , Dietrich Wieland , Christensen Ulrich , Wicht Johannes
Published: March 2022

The analysis of the recent gravity measurements of Jupiter and Saturn reveal that the zonal winds observed on their surfaces reach several thousand kilometres deep into their atmospheres. However, it remains unclear which mechanism prevents them from penetrating deeper. Recent models suggest that a stably stratified region would yield the desired effect.
In this study we systematically explore the dynamics in a spherical shell where the lower third is stably stratified while convection in the outer region drives multiple zonal winds, similar to those observed on Jupiter or Saturn. We perform numerical simulations with the magnetohydrodynamic code MagIC and ignore magnetic effects in order to simplify the problem. Using a rigid lower boundary condition, vigorous multiple jets begin to develop at mid to high latitudes once the stable stratification is strong enough to effectively decouple the jet dynamics from the lower boundary. We find that the jet amplitude decay at the stable layer boundary is proportional to Ω/N, where Ω is the rotation rate and N the Brunt-Väisälä frequency that quantifies the degree of stable stratification.
Furthermore, the penetration depth of the jets is directly proportional to the jet width, i.e. the stable layer acts as a low-pass filter on the zonal winds. The structure of the winds also changes. In the convective region they are invariant along the axis of rotation, as expected. However, in the stable layer the location of the peaks in the zonal wind profile become more radially invariant with depth. This shift from cylindrical to a more spherical geometry in
the flow structure occurs due to meridional flows at the interface, thermal winds and the inverse buoyancy force in the stable layer.
The three-dimensional stress field around the margins of the Adriatic Plate derived from source mechanisms
Authors: Glück Elisabeth , Meier Thomas , Stipcevic Josip
Published: March 2022

At present time, the formerly much larger Adriatic Microplate is still actively being subducted beneath the Apennines and the Dinarides-Hellenides zone with continental collision and related processes occurring under the Alps and the Dinarides. These tectonic processes along with the large-scale component of the northward moving African Plate resulted in a complex 3D stress field.

In the light of the complex tectonic processes accompanying the movement of the Adriatic Plate, we aim to investigate the three-dimensional stress field in that area by stress inversion using focal mechanism data from the available CMT and RCMT earthquake catalogues. The focal mechanisms are inverted to better understand the stress regime in that region and how the stress pattern is depending on the current tectonic setting. A staggered grid algorithm was used for binning the focal mechanisms before the inversion.

The calculated 3D stress field indicates that the direction of the large-scale convergence of Africa and Eurasia is similar to the dominating direction of the maximum horizontal stress axis in the western central Mediterranean, with the exception of the Apennines, where the subduction of the Adriatic Plate beneath the northern Apennines is the primary source of stress. On the eastern margin of the Adriatic Plate the lack of deeper seismicity and a back arc basin, as well as the orogen normal orientation of the maximum horizontal stress axis in the Dinarides is pointing towards a continental subduction zone with an aseismic delaminating slab of lower lithosphere without a significant slab pull component.
Changes of the stress pattern within the Adriatic Plate may result from intraplate deformation, which points towards a fragmentation of Adria along the Mid Adriatic Ridge into two subplates, Adria Sensu Strictu in the north and Apulia in the south. While Adria Sensu Strictu is moving independently from Africa, Apulia is depending on the larger plates movement.
The inversion of the focal mechanisms from the Hellenic Subduction Zone yields results about the rotation of the stress field with depth, as the maximum horizontal stress rotates from trench normal at shallow depths to trench parallel deeper down.
Long-term destabilization of retrogressive thaw slumps (Herschel Island, Yukon, Canada)
Authors: Eppinger Saskia , Krautblatter Michael , Lantuit Hugues , Fritz Michael , Lenz Josefine , Angelopoulos Michael
Published: March 2022

Retrogressive thaw slumps (RTS) are a common thermokarst landform along Arctic coastlines and provide a large amount of material containing organic carbon to the nearshore zone. The number of RTS has strongly increased since the last century. They are characterized by rapidly changing topographical and internal structures e.g., mud flow deposits, seawater-affected sediments or permafrost bodies and are strongly influenced by gullies. Furthermore, we hypothesize that due to thermal and mechanical disturbance, large RTS preferentially develop a polycyclic behavior.

To reveal the inner structures of the RTS several electrical resistivity tomography (ERT) transects were carried out in 2011, 2012, and 2019 on the biggest RTS on Herschel Island (Qikiqtaruk, YT, Canada), a highly active and well-monitored study area. 2D ERT transects were conducted crossing the RTS longitudinal and transversal, always reaching the undisturbed tundra. Parallel to the shoreline, and crossing the main gully draining the slump, we applied 3D ERT which was first measured in 2012 and repeated in 2019. The ERT data was calibrated in the field using frost probing to detect the unfrozen-frozen transition and with bulk sediment resistivity versus temperature curves measured on samples in the laboratory.

The strong thermal and topographical disturbances by gullies developing into large erosional features like RTS, lead to long recovery rates for disturbed permafrost, probably taking more than decades. In this study we demonstrate that ERT can be used to determine long-lasting thermal and mechanical disturbances. We show that they are both likely to prime the sensitivity of RTS to a polycyclic reactivation.
Modeling Aboveground Biomass and carbon sequestration at local and national scale with in-situ and remote sensing data
Authors: Foresta Luca , Alkema Sake , Anders Niels , Masselink Rens , Schut Vincent , Takacs Sacha , Vrielink Arjen
Published: March 2022

Monitoring carbon release and sequestration is now more important than ever. Not only to confirm that carbon sinks remain intact or vulnerable ecosystems do not further degrade, but also to keep track of our journey towards carbon neutrality, where increasing efforts to offset CO2 emissions have been initiated. Amongst a number of solutions, carbon trading schemes have been introduced, such as the EU Emission Trading System that is used in programs where local smallholder farmers benefit from transitioning towards agroforestry. Critical to the success of such programs is the use of accurate, scalable and transparent remote sensing technologies that objectively monitor the carbon that trees in a given plot of land have removed from the atmosphere.

At Satelligence, we exploit radar and optical satellite data worldwide and at scale to empower clients to combat deforestation and decrease carbon losses, as well as to protect biodiversity and prevent land degradation. In this contribution, we will present our approach to model Aboveground Biomass (AGB) over tropical moist forests at (sub) national scale based on data from several Earth Observation missions (GEDI, Sentinel-1, Sentinel-2, Landsat) and machine learning models. In-situ data, where available, are integrated to improve models at local and regional scales. We will show preliminary results of modeled AGB and carbon sequestration over large areas as well as individual agricultural plots for selected countries in Africa and South America.
Recent decadal weakening of the summer Eurasian westerly jet attributable to anthropogenic aerosol emissions
Authors: Dong Buwen , Sutton Rowan , Shaffrey Len , Harvey Ben
Published: March 2022

The Eurasian subtropical westerly jet (ESWJ) is a major feature of the summertime atmospheric circulation in the Northern Hemisphere. Here, we demonstrate that four reanalysis datasets show a robust and substantial weakening trend in the summer ESWJ over the last four decades, amounting to a total change of approximately 7%. This weakening has been linked to significant impacts on extreme weather in the northern hemisphere. Furthermore, we use climate model simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to identify the causes of the weakening trend. Our results strongly suggest that anthropogenic aerosols were likely the primary driver of the weakening ESWJ. In particular, warming over mid-high latitudes due to aerosol reductions in Europe, and cooling in the tropics and subtropics due to aerosol increases over South and East Asia acted to reduce the meridional temperature gradient at the surface and in the lower and middle troposphere, leading to reduced vertical shear of the zonal wind and a weaker westerly jet in the upper troposphere. Our results suggest that if, as expected, Asian anthropogenic aerosol precursor emissions decline in future, we should anticipate a renewed strengthening of the summer ESWJ.
Using high-resolution geochemistry to monitor variations in magma dynamics during eruption
Authors: Ubide Teresa , Márquez Álvaro , Magee Ruadhán , Ancochea Eumenio , Huertas María José , Sanz David , Herrera Raquel , Coello-Bravo Juan Jesús , MacDonald Alice , Mulder Jack , Conn Emily , Caulfield John Thomas , Galindo Inés
Published: March 2022

Volcano monitoring makes it possible to indirectly visualise magma plumbing systems and follow the onset and evolution of eruptions. While geophysical data provide real-time information on magma transfer and storage, the petrology of erupted products is crucial to assess magma composition and eruptive style. However, erupted magmas often carry recycled crystals which affect bulk rock compositions, masking variations in erupted melts. Here, we explore the use of high-resolution geochemistry to resolve subtle variations in melt composition on the scale of days to years. We investigate recent basaltic eruptions in a variety of geodynamic settings and with distinct eruptive frequencies, including Mount Etna in Sicily (Italy) and Cumbre Vieja in La Palma (Canary Islands, Spain). We demonstrate that targeted laser ablation mass spectrometry can rapidly determine variations in the chemical composition of melts within the plumbing system, which may add petrological insight to volcano monitoring efforts.
Seismic sliding of the single fault under fluid injection 
Authors: Riga Vasily , Turuntaev Sergey
Published: March 2022

Seismicity associated with fluid injection into the subsurface is one of the most important issues worldwide. Fluid injection near a fault could lead to seismic sliding of the fault and as a consequence to significant seismic events. In the presented research, we study the single fault behavior under the action of a single well injection near the fault. Various cases of fluid injection and friction properties of the fault are considered. To describe the friction on the fault we use two-parameter rate-and-state law. The fault has zones characterized by velocity-weakening and velocity-strengthening friction behavior. We analyze how injection rate and volume and parameters of the friction law influence the fault sliding dynamics and seismicity level. As the result, we get conditions that are favorable for the occurrence of noticeable seismicity and dependence of seismicity parameters on injection parameters.
Reconstructing the surface temperature fields of the Last Glacial Maximum using climate models and data.
Authors: Annan James , Hargreaves Julia , Mauritsen Thorsten
Published: March 2022

We present a new reconstruction of global climatological temperature fields for the Last Glacial Maximum, which improves on our previous work in several important ways.

The method combines globally complete modelled temperature fields, with sparse proxy-based estimates of local temperature anomalies. We use a localised Ensemble Kalman Smoother, which ensures spatially coherent fields that both respect the physical principles embodied in the models, and are also tied closely to observational estimates.

We use the full set of PMIP2/3/4 model simulations, but perform some filtering of the simulations to remove duplicates and closely related models. We also de-bias the ensemble and show via sensitivity tests that this can be an essential step in the process, although it has little effect in this particular application. Specifically, any bias in the prior ensemble leads to a significant bias (which may take roughly 70-80% of its initial magnitude) in the posterior estimate. Thus we recommend that this step is taken in similar reconstructions unless the researcher is confident that the bias in the prior ensemble is low.

We combine the prior ensemble with a wide range of proxy-based SST and SAT estimates of local temperature to ensure the best possible global coverage. Our reconstruction has a global mean surface air temperature anomaly of -4.5 +- 0.9C relative to the pre-industrial climate, and thus is slightly cooler than the estimate of Annan and Hargreaves (2013), but rather less cold than the estimate of Tierney et al (2020). We show that much of the reason for this latter discrepancy is due to the choice of prior.
Reconstructing fluid pathways by studying dedolomitization process: example of the Benassal Formation, Maestrat Basin, Spain
Authors: Hoareau Guilhem , Centrella Stephen , Beaudoin Nicolas E. , Callot Jean-Paul
Published: March 2022

Dedolomitization i.e. replacement of dolomite by calcite, is an important fluid-mediated replacement process occurring during carbonate diagenesis in basins. Especially, dedolomitization impact local reservoir rock properties, affecting the reservoir quality and rheology. The process of dedolomitization have been the subject of several studies but still, the controlling mechanism is not fully understood.

We investigate samples from the Maestrat Basin in Spain, formed during the upper Jurassic- lower Cretaceous. Between the Eocene and the Oligocene, the bassin recorded a compressive event and a general surrection responsible of dedolomitization. The detailed investigation of the progressive replacement of the original dolostone to the newly formed rock composed by calcite provide a key example to understand the dedolomitization process. Across the replacement interface, crystallographic orientation (EBSD) of the parent dolomite crystal is preserved in the calcite and no chemical zonation for major elements (EPMA) are visible in both phases, supporting a dissolution-precipitation mechanism. In order to better constrain the chemical evolution of the reaction, quantitative trace elements mapping (fs-LA-ICP-MS) was carried out and coupled to mass balance equations to quantify the elements gained and lost during the reaction. Results show a net gain of mass (~5%) with a loss of heavy Rare Rarth Elements and a gain in light ones. The specific gain in Zn and Rb pinpoints that the infiltrated fluid flowed through MVT deposits already present in the area.
Tracing upper mantle flow patterns through continent-scale hiatus surfaces in the Indo-Atlantic Realms since the Upper Jurassic
Authors: Vilacís Berta , Hayek Jorge N. , Bunge Hans-Peter , Friedrich Anke M. , Carena Sara
Published: March 2022

Mantle convection is a fundamental driving force of plate tectonics. It is commonly perceived that mantle convection is difficult to constrain directly. However, the convection process affects the Earth surface imprints the geological record. In particular, the positive surface deflections driven by mantle convection create erosional/non-depositional environments, which induce gaps in the stratigraphic record (i.e., an absence or thinning of a sedimentary layer). Modern digital geological maps allow us to map the largest of such un/-conformable surfaces at continental scale systematically.
We report our continent-scale hiatus mapping in geological series across America, Europe, Africa, and Australia, from the Upper Jurassic onward. We find significant differences in the spatial extent of hiatus patterns across and between continents, which is on the order of 2000 – 3000 km in diameter. These surfaces change at geological series, ten to a few tens of millions of years (Myrs). This duration is significantly shorter than the timescale of mantle convection of about 100 – 200 Myrs, implying that different timescales for convection and topography in convective support must be an integral component of time-dependent geodynamic Earth models. Our results call for intensified collaboration between geodynamicists and geologists to test geodynamic Earth models by assembling relevant geological observations at continental scales.
Visualization of fluorescent microplastics in soil column experiments in different depths
Authors: Bogner Christina , Rolf Markus , Laermanns Hannes
Published: March 2022

Microplastics are ubiquitous in the terrestrial environment and have also been detected in soils. However, how microplastics are transported vertically in the soil is still a matter of research. Especially, the influence of precipitation, preferential pathways and bioturbation on the vertical translocation of microplastics is still unclear. One cause is the time-consuming microplastic analysis in soils that requires substantial sample pretreatment. Additionally, we are still lacking a standard protocol to quantify and qualify microplastic particles in environmental samples.

Therefore, in this study, we present a method for irrigation experiments with soil column to study the vertical transport of microplastics. In the upper 2 cm of the column, fluorescent microplastics are added. We spike the irrigation water with deuterium oxide to trace the breakthrough of the water during the irrigation experiment. After the irrigation experiment, the soil column is frozen and subsequently cut in 2 cm slices and photographed under UV illumination. Then, we process the images by the software MP-VAT to analyse the distribution of the MP particles within the slices and within the soil column.
Structurally controlled regional groundwater circulation: Origin of geothermal springs in Sri Lanka
Authors: Bandara Dilshan , Heinze Thomas , Smit Jeroen , Wohnlich Stefan
Published: March 2022

In the context of switching power generation towards renewable energy sources, the geothermal exploration of low enthalpy systems has gained interest also in regions with little to no recent tectonic or magmatic activity such as Sri Lanka. Sri Lanka has 9 low enthalpy systems with yet unknown heat generating mechanisms besides several existing hypotheses. Recent studies of such kind of low enthalpy geothermal systems hypothesize that fault network and recharge elevations are the main factors controlling the origin of the hot springs.

We studied the fault network, shear zones, and regional fracture networks to understand the heat flow causing the Sri Lankan hot springs. Remote sensing and geophysical methods were used to identify and analyze lineaments. We find that (1) The peak circulating temperatures of deeply circulating meteoric water depend on the elevation of the recharge zone for the corresponding hot spring. (2) Hot springs are formed in a terrain with a long fault / shear zone (starting from the highlands) when cross cuts with a regional fracture network occur in or near to the hot spring fields. (3) Highest number of hot springs in the country relates with the fault network that crosses the Mahaweli shear zone at the boundary of the two geological complexes Highland and Vijayan.

We conclude that the fault network that crosses both the central highlands and the Vijayan Complex plays a major role in the heating of deep percolating water, as it transports the water over more than hundred kilometers distance from the recharge zones to the hot springs. 
Estimating the subsurface thermal conductivity and its uncertainty for shallow geothermal energy use – a methodology based on publicly available data
Authors: Heim Elisa , Laska Marius , Becker Ralf , Klitzsch Norbert
Published: March 2022

Over 50% of the energy consumption in Europe is used for heating and cooling, of which the majority still comes from fossil fuels. For the heating and cooling supply of buildings, heat pumps using borehole heat exchangers (BHE) are an efficient and sustainable alternative. Design and performance of BHE fields strongly depend on the thermal properties of the subsurface. For the dimensioning of BHE fields, the subsurface properties are assessed using geothermal potential maps published by federal states or authorities.

Such maps are created based on available geological and hydrogeological subsurface data. From these data, the stratigraphic sequence a BHE would intersect is inferred and thermal properties are assigned to the rock sequence. The mean thermal conductivity of the intersected sequence has a high uncertainty that is not quantified in most geothermal potential estimates. Moreover, geothermal potential maps are often not comparable because the used calculation methods differ in terms of complexity and calculated quantity. In Germany, for example, almost each of the federal states published its own geothermal potential map showing different quantities.

For these reasons, we propose an approach to estimate the subsurface thermal conductivity together with its uncertainty. To enable applicability to datasets of different regions, e.g., all German federal states, the method takes only publicly available and standardized hydrogeological and geological data as input. Thermal conductivity estimation takes place on

1) a large scale, to obtain a general estimate of thermal conductivity, and

2) on a fine scale, to update the large-scale estimate in smaller target areas.

For both estimations, we consider uncertainty by assigning not only the mean but also the minimum and maximum thermal conductivities of each rock type to the intersected sequence. Data handling and initiation of calculations is done via a geoportal. It connects the calculation method to geodata servers, instead of storing data locally, thus ensuring data up-to-dateness. This way, the approach does not only estimate the thermal conductivity, but also automatizes the cumbersome step of geological data gathering for all types of subsurface investigations.

We demonstrate the approach using data from the federal state of Hamburg and compare our results to a thermal conductivity map published by the city of Hamburg.  The partly considerable differences between the two estimates illustrate the uncertainty of the geothermal potential, and thus the need to communicate it.