bluuebunny/crossref_metadata_2025 huggingface dataset:
Present-day upper mantle structure of the Alps: insights from data-driven dynamic modelling 
Authors: Kumar Ajay , Cacace Mauro , Scheck-Wenderoth Magdalena , Bott Judith , Götze Hans-Jürgen , Kaus Boris
Published: March 2022

Present-day surface deformation in the Central Alps, that is, uplift and upper-crustal level seismicity in contrast to its northern and southern forelands, has been attributed to surface (i.e., climatic) and tectonic processes (i.e., subduction, slab detachment/break-off, mantle flow). Understanding the relative contribution of these processes is fundamental to understanding their coupling and role in mountain building. The present-day 3D architecture of the lithosphere (i.e., lateral variations of crustal layers and lithospheric mantle thickness) and asthenosphere (i.e., subducted slabs, attached or detached to the orogenic lithosphere) resulting from tectonic processes operating at geologic time scale serve as a boundary condition to test the contribution of surface processes. While the crustal structure in the Alps is well constrained by seismic and gravity data, the upper mantle (i.e., lithospheric mantle and asthenosphere) structure differs from that due to the diversity and subjective interpretation of seismic tomography models. We convert the results of regional shear-wave seismic tomography models to temperature models using the Gibbs-free energy minimization algorithm to define the base of the lithosphere and the position of slabs in the asthenosphere. Our results show that the shallow/attached slab in the Northern Apennines is a common feature in different tomography models, but there are differences in the Alps area. We statistically cluster tomography models into three end-members corresponding to the mean and 67% confidence intervals to address these differences objectively. These end-members represent scenarios ranging from shallow/attached slabs to almost no slabs in the Northern Apennines and Alps. The three end-member scenarios are then used as an input to model the topography and velocities by solving the buoyancy-forces driven instantaneous flow, subject to the first-order rheological structure of the lithosphere-asthenosphere system. Modelled topography and velocities are compared to the first-order patterns of observed topography and GPS derived vertical velocities to discern among the end-member scenarios. Our preliminary results suggest that the lithospheric slab subducting beneath the Northern Apennines should be connected to the overlying lithosphere, whereas it appears to be detached along most of the Alps. The sensitivity of results to the viscosity structure of the crust, lithosphere, and asthenosphere will be discussed.  
Mapping the extent of seismoturbidites near the southern Dead Sea Fault in the Gulf of Aqaba
Authors: Ribot Matthieu , Jónsson Sigurjón , Klinger Yann , Avsar Ulaş , Bektaş Zeynep
Published: March 2022

Despite multiple research efforts since the late 1950’s, many questions regarding the earthquake activity of the Dead Sea Fault (DSF) remain, in particular for its southernmost portion in the Gulf of Aqaba. This is due to its offshore location and little-known interactions with the Red Sea rift system. The emergence of the NEOM city-project in northern Saudi Arabia and the planned King Salman road crossing across the Gulf of Aqaba have made it important to find answers for these questions related to the earthquake hazard of the region. The last major earthquake in the Gulf of Aqaba occurred in 1995 along one of the main strike-slip fault segments in the gulf, bringing both extremities of the fault rupture closer to failure. Studies of the DSF have found that large events along the entire DSF cluster during relatively short active seismic periods lasting about 100-200 years, separated by longer quiescent periods of about 350-400 years. From a tectonic point of view, the time gap between 1995 and the previous major earthquake in AD1588 conforms to this scheme and suggests that the DSF might be ripe for a new earthquake sequence, with the 1995 earthquake as the starter. That said, new results from GPS and InSAR observations have pointed to possible fault creep in the southern part of the gulf, which would significantly decrease the seismic hazard in the area. To explore this possible creep and to test the clustering model, we investigate new sub-bottom profiling data acquired in December 2019 in the Gulf of Aqaba. We aim to map the extent of sand layers present in the different sub-basins of the gulf and to correlate them with seismoturbidite layers found in sediment cores collected in 2018. By looking at the geographic extent of these sand layers, we also aim to define the source of the coarse deposits, or at least, to determine whether they are related to the regular sediment influx or linked to turbidites generated by slope failures during large earthquakes. Our preliminary results indicate that the sub-bottom profiling data allow us to map sand layers up to a depth of about 8 meters. Considering a sedimentation rate in the gulf between 0.2 - 0.4 mm/year, we could be able to gain an overview of the sediment infill of the Gulf of Aqaba over the last 20 ky or more. Even if the resolution of the sub-bottom profiling data is lower than that of the sediment cores, and the assumptions made for the correlation of the sand layers, due to the scattered grid, do not help to constrain properly the source of the deposits, we can still propose a longer-term overview of the earthquake activity and discuss the temporal organization of the large events in the area.
Regional and model-specific response types in a global gridded crop model ensemble
Authors: Müller Christoph , Jägermeyr Jonas , Elliott Joshua , Ruane Alex , Balkovic Juraj , Ciais Philippe , Falloon Pete , Folberth Christian , Francois Louis , Hank Tobias , Hoffmann Munir , Izaurralde Cesar , Khabarov Nikolay , Liu Wenfeng , Olin Stefan , Pugh Thomas , Wang Xuhui , Williams Karina , Zabel Florian
Published: March 2022

Crop models are often employed to project crop yields under changing conditions such as global warming and associated management change for adaptation. Multi-model ensembles are promoted to enhance the robustness of projections, but questions remain on what causes often large differences between projections of individual models. Global Gridded Crop Models (GGCMs) are especially exposed to this question when applied for assessing climate change impacts, adaptation, environmental impacts of agricultural production, because their results are used in downstream analyses, such as in integrated assessment or economic modeling for projecting future land-use change. Even though global gridded crop models are often based on detailed field-scale models or have implemented similar modeling principles in other ecosystem models, global-scale models are subject to substantial uncertainties from both model structure and parametrization as well as from calibration and input data quality.

AgMIP’s Global Gridded Crop Model Intercomparison (GGCMI) has thus set out to intercompare GGCMs in order to evaluate model performance, describe model uncertainties, identify inconsistencies within the ensemble and underlying reasons, and to ultimately improve models and modeling capacities. In phase 2 of the GGCMI activities, 12 modeling groups followed a modeling protocol that asked for up to 1404 31-year global simulations at 0.5 arc-degree spatial resolution to assess models’ sensitivities to changes in carbon dioxide (C; 4 different levels) temperature (T; 7 different offset levels), water supply (W; 9 levels), and nitrogen (N; 3 levels), the so-called CTWN experiment (Franke et al. 2020; http://dx.doi.org/10.5194/gmd-13-2315-2020).

We here present analyses of model response types using impact response surfaces along the C, T, W, and N dimensions, respectively and collectively. Doing so, we can understand differences in simulated responses per driver rather than aggregated changes in yields. We find that models’ sensitivities to the individual driver dimensions are substantially different and often more different across models than across regions. A cluster analysis finds regional and model-specific patterns. There is some agreement across models with respect to the spatial patterns of response types but strong differences in the distribution of response type clusters across models suggests that models need to undergo further scrutiny. We suggest establishing standards in model process evaluation not only against historical dynamics but also against dedicated experiments across the CTWN dimensions.
Disentangling in-stream nitrate uptake pathways based on two-station high-frequency monitoring in high-order streams
Authors: Zhang Xiaolin , Yang Xiaoqiang , Hensley Bobby , Lorke Andreas , Rode Michael
Published: March 2022

Stream and river systems are an important compartment of nitrogen (N) transport and retention from terrestrial landscape to marine ecosystems. In-stream nitrate uptake in rivers involves complex assimilatory and dissimilatory pathways, which often exhibit spatiotemporal variability due to stream hydraulic, biotic (e.g., phytoplankton and periphyton) and abiotic (e.g., temperature and light availability) variations. Two-station based multi-parameter high-frequency monitoring allows quantitative disentangling of multi-path nitrate uptake dynamics at the reach scale. However, such monitoring and analysis are still limited to few small river types (e.g., headwaters and spring-fed rivers) and have not been well explored in higher order streams with varying hydro-morphological and biogeochemical conditions. Here, we conducted the two-station high-frequency monitoring in five high-order stream reaches in central Germany (i.e., two in the 4th order Weiße Elster River and three in the 6th order Bode River). Two-station 15-min time series of nitrate-N and dissolved oxygen were used to calculate the N mass balance and whole-stream metabolism, respectively. The mass-balance based net nitrate uptake rates (UNET) differed between reaches with contrasting morphology (e.g., 13.8±3.85 mg N h-1 in the more natural Weiße Elster compared to 2.05±0.83 mg N h-1 in the modified reach of Bode), as well as between different periods in the same reach (e.g., higher in post-wet period than in dry period). The measured GPP and the related autotrophic nitrate assimilation (UA) were determined by seasonal-varying radiation and riparian-canopy shading conditions. Heterotrophic N uptake (UD), including denitrification and heterotrophic assimilation, was further disentangled as the difference between UNET and UA. This rarely reported uptake pathway showed relatively higher values than UA, especially during late spring periods; moreover, it exhibited obvious diel signals that are significantly negatively correlated with DO. We further summarized difficulties and cautious considerations in conducting such two-station monitoring campaign at larger reach scales. In conclusion, benefiting from the less labor-consuming and high-frequency sensor monitoring, the two-station methods for N mass balance and stream metabolism can be applied at larger reach scales, and can well disentangle the multiple N uptake pathways that often exhibit high spatiotemporal heterogeneity.
Shallow crustal architecture of the foreland Kumaon Himalaya analysing high-resolution seismic data
Authors: Verma Shashank , Ghosal Dibakar
Published: March 2022

Ongoing under-thrusting between Indian and Eurasian plate poses a serious concern to millions of human lives residing in the foreland Himalayan. A devastating earthquake in the Central Seismic Gap (CSG) is anticipated in various studies with a possible estimated slip of ~10 m, thereby a thorough analysis of the foreland set up is essential. Present study aims the Kumaon Himalaya of the CSG using the high-resolution seismic sections along profiles PGR4, PGR5 and PGR6. Profiles PGR4 and PGR5 trend N-S direction across the Kaladungi Fault (KF) and Himalayan Frontal Thrust (HFT), whereas the PGR6 trends E-W in the Indo-Gangetic plain. Here we mostly observe Siwalik formation and alluvial deposits of the Dabka and Baur rivers. PGR4 and PGR5 clearly show evidence of south verging faults that displace the Siwalik formation. We observe Upper, Middle and Lower Siwalik rocks at ~0.82 and 0.62 s, ~1.38 and 1.27s, and ~1.88 and 1.85 s TWTT in the footwall and hanging wall sides of KF, respectively. Sedimentary deposits near the KF is highly fractured and host multiple traces of the Fault among which two reach to the surface inferring these are active. We further observe highly folded top sediments with evidence of fault bend folding at North of the KF. In the Indo-Gangetic plain, we observe gentle folding in the Lower Siwalik deposits and trace of a south verging fault that meets the Main Himalayan Thrust (MHT) at ~3 s TWTT displacing the Lower Siwalik deposits by ~ 0.0368 s TWTT. Evidence of such folding and displacements in the formation reveal that foreland Himalaya is conducive to rupture propagation of any major earthquakes developed along MHT over the CSG.
The effect of chemistry on the transport of silica encapsulated DNA magnetite microparticles in saturated porous media
Authors: Mahmoud Ahmed , Willem  Foppen Jan , Bogaard Thom
Published: March 2022

In recent years, DNA-tagged silica microparticles with a superparamagnetic core (SiDNAMag) have been used as an environmental tracer in a variety of applications, including fractured reservoir characterization, coarse-grained aquifer material, and fractured crystalline rock. The primary advantages of tagging silica colloids with DNA are that it provides the colloids with a unique DNA sequence and allows for investigation at low concentrations using traditional microbiological procedures. However, the processes that regulate the fate and transport of SiDNAMag in the subsurface and the impact of environmental conditions on the behaviour of these colloidal particles are still not fully investigated. The ultimate goal of this research is to optimize the use of SiDNAMag in groundwater flow systems. Here we focus on the effect of water chemistry (ionic strength and cation valence) on the retention and release behaviour of SiDNAMag upon transport through columns of saturated quartz sand (0.8-1.2 mm). Thereto, SiDNAMag will be suspended in a variety of water chemistries (DM water, NaCl, NaHCO3, CaCl2, and MgCl2, combinations of cations) with varying ion strengths (0.001, 0.005, 0.01 and 0.02 M). At the end of each experiment, columns will be flushed with demineralized water. Collected samples will be magnetically separated and DNA concentrations determined using qPCR. The results will be expressed in sticking efficiencies and retention in the secondary energy minimum as a function of water chemistry and ion strength used. These experimentally determined functions will serve as the basis for predicting and optimizing the use of SiDNAMag in a variety of groundwater flow systems.
Novel methods for deep clustering time series of high-dimension mass spectrometer data
Authors: Taylor Jonathan , Budisulistiorini Sri Hapsari , Hamilton Jacqui , Topping David
Published: March 2022

We present results from an exploratory study investigating deep clustering of high-dimension mass spectrometry data. Field measurements were taken from aerosol filter samples collected at sites in multiple seasons in Beijing and Delhi. ~450 samples were analysed using ultra-high pressure liquid chromatography coupled with heated electrospray ionisation and Orbitrap mass spectrometry (UHPLC-HESI-Orbitrap MS), producing over 1000 molecular markers for each sample, each with a distinctive organic molecule and retention time. With far more dimensions than samples (i.e. more columns than rows), this dataset is not ideal for traditional nearest-neighbour clustering methods as the largest peaks dominate the signal, and nearest-neighbour distances blur as dimensionality increases.

We demonstrate the impact of deep clustering, using autoencoders to reduce data dimensionality. Autoencoders are a deep learning method using two linked neural networks to reduce data dimensionality. One “encoder” network reduces the data to a smaller latent space, while a second “decoder” network increases the dimensionality of the latent space back to the original dimensions of the dataset. The two networks are trained together to minimise loss of information, producing a clusterable latent space with similar information content as the original dataset but with far fewer dimensions.

We present comparisons of deep clustering and traditional hierarchical clustering to identify key molecules and features in the sample time series. We will also demonstrate the impact of prescaling the data, a common technique in the application of neural networks.
The Saint-Ursanne earthquakes of 2000 revisited: Evidence for active shallow thrust-faulting in the Jura fold-and-thrust belt
Authors: Lanza Federica , Diehl Tobias , Deichmann Nicholas , Kraft Toni , Nussbaum Christophe , Schefer Senecio , Wiemer Stefan
Published: March 2022

The interpretation of seismotectonic processes within the uppermost few kilometers of the Earth’s crust has proven challenging due to the often significant uncertainties in hypocenter locations and focal mechanisms of shallow seismicity. Here, we revisit the shallow seismic sequence of Saint-Ursanne of March and April 2000 and apply advanced seismological analyses to reduce these uncertainties. The sequence, consisting of five earthquakes of which the largest one reached a local magnitude (ML) of 3.2, occurred in the vicinity of two critical sites, the Mont Terri rock laboratory and Haute-Sorne, which is currently evaluated as a possible site for the development of a deep geothermal project. Template matching analysis for the period 2000-2021, including data from mini arrays installed in the region since 2014, suggests that the source of the 2000 sequence has not been persistently active ever since. Forward modelling of synthetic waveforms points to a very shallow source, between 0 and 1 km depth, and the focal mechanism analysis indicates a low-angle, NNW-dipping, thrust mechanism. These results combined with geological data suggest that the sequence is likely related to a backthrust fault located within the sedimentary cover and shed new light on the hosting lithology and source kinematics of the Saint-Ursanne sequence. Together with two other more recent shallow thrust faulting earthquakes near Grenchen and Neuchâtel in the north-central portion of the Jura fold-and-thrust belt (FTB), these new findings provide new insights into the present-day seismotectonic processes of the Jura FTB of northern Switzerland and suggest that the Jura FTB is still undergoing seismically active contraction at rates likely <0.5 mm/yr. The shallow focal depths provide indications that this low-rate contraction in the NE portion of the Jura FTB is at least partly accommodated within the sedimentary cover and possibly decoupled from the basement. This trenspressive regime is confirmed by the ML4.1 Réclère earthquake of December 24. 2021, which occurred ~20 kilometres west of St. Ursanne in the uppermost crust.
Defining the basic rules that describe long-term shoreface dynamics: A process-mimicking approach for reservoir modelling
Authors: Argüello Scotti Agustín , Haug Eide Christian , Aarnes Ingrid , Skauvold Jacob , Hauge Ragnar
Published: March 2022

Producing geologically reasonable subsurface reservoir models which also honor wellbore and seismic data is still a major challenge for geoscientists at a range of energy and mining industries. Models based purely on geostatistics usually don’t satisfy the expected representation of geological concepts, while process-based models can hardly be constrained by subsurface data. Our research project GEOPARD aims to add a new tool in this context by providing a process-mimicking approach. In this method, sedimentary units are placed in 3D space constrained by subsurface data while simultaneously following a set of geological rules. This contribution aims to share and discuss the methodological workflow under development, from the geological domain, to test this method on the shoreface accumulation system. The first major step of the workflow is to specify the geological unit(s) to be modelled, which must be of interest as a control upon reservoir heterogeneity and of an adequate scale for representation. Afterwards, geological rules can be defined. These can be classified as (i) element geometry, scale, and infill specifications, (ii) basic element-set rules, which define the expected relationship between a set of geological units, and (iii) advanced element-set rules, which define how these relationship between elements might change over a sedimentary sequence. Each set of rules is linked to appropriate references for justification and exemplified from virtual outcrops of the Blackhawk Formation at Central Utah, which is one of the most studied and best-preserved examples of this type of depositional system. Feedback from the modelling domain is itself incorporated into refining the geological rules, resulting in an iterative effort to improve the methodology. Testing the method in these type of accumulation systems, that can be said to follow relatively straight-forward rules, are key before advancing into systems which typically exhibit more complex sedimentary architecture. We expect that the development of this modelling method can be a powerful tool to produce more useful models for oilfield assessment and development, CO2 storage projects, hydrocarbon exploration, among many others.
Developing a post-processing software for ADCP discharge measurement piloted by an international and inter-agency group: a unique, ambitious experience… and one that works!
Authors: Lennermark Mikael , Hauet Alex
Published: March 2022

Since 2015, 13 agencies from all around the world (9 different countries in Europe, North and South America and Oceania) have been working together in an International Hydrometry Group, a loosely organized group of experts in instruments and methods for measuring discharge in rivers that meets virtually once a month to discuss scientific and technical issues relating to river flow measurements.

A main objective of the group is to lead the development and funding of an open-source software package, QRevInt, for postprocessing ADCP discharge measurements. The agencies participate in funding the software developer (Dave Mueller, Genesis HydroTech) or contribute scientific inputs. They define the annual development workplan and its funding, and monitor progress during monthly monitoring meetings.

In this presentation, the latest version of QRevInt is detailed and the main advantages of the software are explained, including processing of measurements from ADCP of different manufacturers (TRDI and SonTek) with the same calculation assumptions, objectification of the computation of unmeasured flow area (top, bottom, edges, invalid cells or ensembles), calculation of uncertainty and advanced graph options.

The workplan of the group for 2022 is presented, including the ongoing developments of QRevInt, and the new project for a software dedicated to mid- or mean-section ADCP measurement, QRevIntMS.
The carbon cost of Transpiration from Optimality Theory
Authors: Sandoval David , Lavergne Alienor , Prentice Colin
Published: March 2022

Optimality theory states that the plants balance the carbon cost of photosynthesis with the cost of absorbing water thus satisfying a.δ(E/A)/δχ = -b. δ(Vcmax/A)/δχ, where χ is the ratio of leaf intercellular to ambient partial pressure of CO2, “a” is the cost of maintaining the transpiration rate (E), required to support assimilation at a rate A under normal daytime conditions. While “b” is the cost of maintaining carboxylation capacity (Vcmax) at the level required to support assimilation at the same rate. Thus, the “a” cost, theoretically, should express the unit of maintenance respiration of the sapwood per unit of transpiration.

Here, we developed a mathematical expression to calculate the expected “a” cost (aexp) under the optimality framework of the P-model using eddy covariance measurements of CO2 exchange combined with environmental and transpiration measurements from the SAPFLUXNET database.

We then compared aexp against two theoretical formulations of “a”. One (noted atheo1) was estimated as a function of the viscosity of water at a given temperature η(T) compared to that at 25°C, which was proposed by Wang et al., (2017, Nat. Plants). And a second one (noted atheo2), proposed by Prentice et al., (2014, Ecol. Lett.) where “a” depends on the soil-leaf water potential gradient (Δψ), η(T) and parameters defining hydraulic traits and respiration which were obtained from the literature.

The seasonal pattern of aexp suggests that it is more costly for the ecosystem to transpire during the dry months. We found that atheo1 has opposite seasonal variations to aexp and strongly underestimates “a” during dry months. In contrast, atheo2 shows similar seasonal variations to aexp but generally overestimates the aexp values by almost 4 times. Simple regression analyses showed, as expected, that aexp  is inversely proportional to Δψ, but that, opposite to what was expected, it increases with a reduction of the water viscosity.

Overall, our results suggest that an improved formulation of the cost ratio “a” should account for the effect of water stress on transpiration and assimilation in the optimality theory.
An idealized study of convection initiation along orographic drylines
Authors: Serafin Stefano , Potter Emily
Published: March 2022

The climatological frequency of deep moist convection is enhanced in the vicinity of mountainous regions. Most studies to date focus on convection initiation (CI) on the windward side of mountains, but uplift and CI can also occur on their lee side. The factors controlling this phenomenon are only partially understood, but it is frequently hypothesized that a lee-side hydraulic jump may provide the uplift required to initiate lee-side convection.

Here we argue that lee-side CI is best understood as a consequence of low-level convergence along an orographic dryline. The dryline marks the boundary between relatively dry air desceding from the mountains and conditionally unstable air over an adjacent plain. The stronger the convergence along the dryline, the more likely is CI to occur.

We initially focus on the atmospheric conditions leading to strong lee-side convergence and low-level uplift in an unsaturated atmosphere. A variety of scenarios are investigated using an idealised modelling setup, exploring a range of linearity and hydrostaticity of the cross-mountain flow and varying surface fluxes. By computing a convergence budget, we determine the dominant forcings affecting lee-side convergence and how these vary across flow regimes. A relationship is determined between the level of hydrostaticity and linerity of the flow, the strength of lee side convergence, and the corresponding boundary-layer uplift.

We then turn to considering flows with a conditionally unstable leeside environment. We replicate the scenarios in which strong lee-side convergence and low-level uplift are expected, and we determine whether the uplift is actually sufficient to initiate deep moist convection.
Who controls Fe cycling below the SMTZ of the Mediterranean Sea?
Authors: Bosco Santos Alice , Sivan Orit
Published: March 2022

Microbial metabolisms that attain close together different biogeochemical cycles, such as Fe, C, and N, introduce complexity to the traditional redox electron acceptors cascade in sediments, leading to spatial overlap between geochemical gradients. A good example of overlap when considering Fe geochemistry is the oftentimes peaks in dissolved Fe2+ observed below the sulfur-methane transitional zone (SMTZ) in different environments. While anaerobic methane oxidation mediated by Fe reduction (Fe-AOM) might explain the feature in deep lacustrine sediments, our preliminary data indicate that Fe-AOM is not significant in oligotrophic marine sediments. We described Fe speciation, nutrients, and microbiota composition in various sedimentary profiles from the Levantine Basin, Eastern Mediterranean Sea, Israel and observed coupled Fe and N cycling. In the ammonium-rich (2000 µmol L-1) deep methanic sediments, strongly positive correlated increases in dissolved Fe2+ and NO2- (and/or NO3-) via microbe-mediated ammonium oxidation coupled to Fe(III) reduction (Feammox) is proposed. In this environment, the deep availability of Fe2+ favors precipitation of authigenic Fe minerals below the SMTZ.
Rifting in the Red Sea – insights into the rift architecture from geophysical data
Authors: Issachar Ran , Ebbing Jörg , Dilixiati Yixiati , Gómez-García Ángela María
Published: March 2022

Conjugate margins along mature oceans indicate two end-member types of rifted margins, distinguished by their crustal architecture, e.g. the Iberia-Newfoundland and Central South Atlantic. Numerical simulations and analogue models show that these types could be explained by rheology, state of stress (depth depended) and role of magmatism (magma assisted). The Red Sea is a young rift, offering the opportunity to study early break-up conditions and to relate them to the architecture and the type of passive margins. The morphology of the Red Sea indicates variability and dissimilarities between its southern and northern regions, nevertheless, the lithospheric structure of the rift remains elusive, mainly due to lack of high-resolution direct geophysical measurements, e.g. seismic profiles.

In this study, we explore the deep architecture of the Red Sea rift using geophysical data, in particular gravity and magnetic data, and constraints from seismic interpretations, receiver functions and tomographic models. We present a 3D structural and density model for the Red Sea, including the African and Arabian shoulders down to 120 km depth. The model includes four main sections: sediments, crystalline crust (continental and oceanic), lithospheric mantle (including a thermal gradient) and a uniform asthenosphere. In order to test different scenarios, we evaluate combinations of (1) exhumed continental mantle lithosphere (Type I margin) versus wide/ultrawide continental crust (Type II margin), and, (2) limited versus extended distribution of oceanic crust. The 3D gravity model favors Type II architecture and limited oceanic crust in the southern-central parts of the Red Sea rift. In the northern parts, the model cannot distinguish between the pre and post break-up stages.
Synchronization of layer-counted archives using a statistical age-depth model
Authors: Myrvoll-Nilsen Eirik , Riechers Keno , Boers Niklas
Published: March 2022

Layer-counted paleoclimatic proxy records have non-negligible uncertainty arising from the dating process. Knowledge of this uncertainty is important for a rigorous propagation to further analyses; for example for identification and dating of abrupt transitions in climate or to provide a complete uncertainty quantification of early warning signals. This dating uncertainty can be quantified by assuming a probabilistic model for the age-depth relationship. We assume that the number of counted layers per unit of depth can be described using a Bayesian regression model with residuals following an autoregressive process. By synchronizing the chronologies with other archives one can constrain the uncertainties and correct potential biases in the dating process. This is done by matching the chronologies to tie-points obtained by analyzing different archives covering the same period in time. In practice, tie-points can be associated with a significant amount of uncertainty which also needs to be accounted for. We present a theoretically consistent approach which, under certain assumptions, allows for efficient sampling from synchronized age-depth models that match the tie-points under known uncertainty distributions. The model and associated methodology has been implemented into an R-package. 
Developments of the Global Tide and Surge Model
Authors: Veenstra Jelmer , Muis Sanne , Verlaan Martin
Published: March 2022

The Global Tide and Surge Model (GTSM) is a depth-averaged hydrodynamic model, developed by Deltares. GTSM can be used to dynamically simulate water levels and currents, that arise from tides and storm surges. The model is based on Delft3D Flexible Mesh software and has a spatially varying resolution which increases towards the coast. Previous studies with this model used GTSMv3.0 and focused for instance on operational forecasting, reanalysis and climate projections and estimation of return periods (Muis et al., 2020; Dullaart et al., 2021), satellite altimetry (Bij de Vaate, 2021), changes in tides due to sea level rise and various others.

Significant improvements in model performance were made in the newest GTSMv4.1, released in 2021. This model with increased resolution and improved representation of physical processes was calibrated by applying bathymetry and friction correction (Wang et al., 2021). From GTSMv3.0 to GTSMv4.1, the model performance showed great improvements with a 37% reduction of the root-mean-squared-error between modelled and observed tides from 17.8 cm to 11.3 cm.

The model development is an ongoing and continuous effort. The current developments are to improve the grid+bathymetry, representation of the sea-land interface, improving the spatial distribution of internal tide energy dissipation and the inclusion of other baroclinic processes like steric and radiational tides. Preliminary results show improvements in several areas. Furthermore, improving geometry representation by cutting parts of coastal cells with a landboundary often shows to improve the model performance just as significant as a resolution increase, while saving computational cost.
A risk model for everyone: supporting climate adaptation decisions based on economic and social vulnerability
Authors: Fairless Chris , Schmid Emanuel , Prothi Amit , Bresch David
Published: March 2022

We present the Rapid Economics of Climate Adaptation tool which releases later this year. Built to provide out-of-the-box risk modelling anywhere on the planet, the tool is a user-friendly interface exploring climate risk data and adaptation options in terms of economic and human impacts. In the back end it connects to the CLIMADA (CLIMate ADAptation) risk model which runs rapid calculations while the user navigates.

The tool is built to assess the economic and human impacts of natural disasters in different climate scenarios and to describe the co-benefits of adaptation measures. Of particular note is a new, quantitative description of social vulnerability, allowing the user to explore vulnerability-driven adaptation within and between communities.

This first version of the tool includes tropical cyclone wind and extreme heat hazards with human and economic exposure. It will be expanded with additional hazards, impacts and co-benefits over time, and will extend to cover impacts on biodiversity.

The tool is open source, with the web front end connecting to a new, public remote calculations API, where users (either on the site, from a separate python client or via HTTP requests) can trigger CLIMADA risk calculations.

We aim to support climate adaptation decision-makers without access to bespoke, often expensive, modelling or who don’t have the technical capacity to conduct their own studies.

The work is conducted by the Weather and Climate Risks Group at ETH Zurich, the Adrienne Arsht-Rockefeller Foundation Resilience Center and Vizzuality and is partly funded the Swiss Re Foundation.
Characterization of microplastics using fluorescence spectroscopy and online single particle fluorescence measurements
Authors: Gratzl Jürgen , Seifried Teresa M. , Koyun Ayse , Grothe Hinrich
Published: March 2022

Microplastic particles in the atmosphere, even in very remote locations (Allen 2021; Allen 2019, Materić 2020, 2021), have attracted considerable interest in recent years. The origin, chemical transformation, transport and abundance of airborne microplastics still remains largely unexplained. Detection techniques are scarce and often include visual classification with the naked eye or with an optical microscope (Lulu 2021).

In this study, fluorescence spectroscopy is used to characterize microplastic particles in the laboratory. Pure samples of polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP), as well as everyday products (PET-drinking bottle, packaging) were shredded with a swing mill into particles < 100 μm. The samples were analyzed with a fluorescence spectrometer, revealing clear excitation-emission maxima, with slight differences among the samples. To test if fluorescence is a promising property for the online detection of airborne microplastics, we use a Bioaerosol Sensor, which enables single particle fluorescence measurements at two excitation wavelengths and in two emission windows. For this aim, the microplastic particles are dispersed in air and are characterized by the bioaerosol sensor.

 

Literature:

Allen, S., et al. "Evidence of free tropospheric and long-range transport of microplastic at Pic du Midi Observatory." Nature communications 12.1 (2021): 1-10.

Allen, Steve, et al. "Atmospheric transport and deposition of microplastics in a remote mountain catchment." Nature Geoscience 12.5 (2019): 339-344.

Materić, Dušan, et al. "Nanoplastics transport to the remote, high-altitude Alps." Environmental Pollution 288 (2021): 117697.

Materić, Dušan, et al. "Micro-and nanoplastics in Alpine Snow: a new method for chemical identification and (semi) quantification in the nanogram range." Environmental science & technology 54.4 (2020): 2353-2359.

Lv, Lulu, et al. "Challenge for the detection of microplastics in the environment." Water Environment Research 93.1 (2021): 5-15.
Concentrations and migration forms of strontium in groundwater used for drinking within the Moscow artesian basin (Russia, Bryansk region)
Authors: Kolmykova Liudmila , Korobova Elena
Published: March 2022

The geochemical features of stable strontium distribution in groundwater of the Upper Devonian hydrogeological complex within the southwestern flank of the Moscow artesian basin used for centralized drinking water supply in the northeastern part of the Bryansk region were considered in order to detail the potential influence of additional geochemical factors on the manifestation of endemic decease caused by natural iodine deficiency.

Strontium concentration in water samples varied from 0.21 to 28.8 mg/l (median (Me) = 1.03 mg/l, n=34). The analysis of strontium distribution with considering the genetic features of water-bearing rocks showed no significant differences in the content of this element in the waters of depositions of the Frasnian (Me=0.86 mg/l, n=25) and Famennian stages (Me=1.09 mg/l, n=9) (p<0.01). The main sources of strontium in investigated groundwater are strontium-containing minerals (celestine) or strontium impurities in limestones of varying degrees of gypsification associated with the Upper Devonian carbonate rocks (Sr correlation with SO4: r<0.05=0.78). The maximum levels of strontium, which significantly exceed the Russian hygienic standard for drinking waters (7 mg/l), were detect in groundwater of Famennian sediments of the Rognedinsky district of the Bryansk region (>20 mg/l). Given the lack of significant correlation between strontium content and water salinity, which is usually observed for strontium-enriched artesian waters of regional hydrogeochemical provinces (Kraynov et al., 2012) it can be explained by the existence of natural local strontium anomaly in this area (Сa/Sr <7).

Membrane filtration of water samples allowed suggesting that strontium migrate in fresh and low-salinity waters mainly within dissolved fraction of groundwater (divalent cation and complexes with sulfate, chloride and hydrocarbonate) with sizes not exceeding 0.45 µm.

The presence of a local anomaly of strontium-containing waters within the Moscow artesian basin, which impair the quality of drinking water in this area, can be a factor of potential risk to the health of the local population living under conditions of iodine deficiency.

 

The reported study was funded by the Vernadsky Institute federal budget (research task #0137-2019-0006). The Field work was partly funded by RFBR and BRFBR project #20-55-00012 and BRFBR project # Х20Р-386.
Salt welding during canopy advance and shortening in the Green Canyon area, northern Gulf of Mexico
Authors: Evans Sian , Alshammasi Turki , Jackson Christopher
Published: March 2022

Welds form due to the tectonically-induced thinning and/or dissolution of salt, with their composition and completeness thought to at least partly reflect their structural position within the salt-tectonic system. Despite their importance as seals or migration pathways for accumulations of hydrocarbons and CO2, we have relatively few examples of drilled subsurface welds; such examples would allow us to improve our understanding of the processes and products of welding, and to test analytical models of the underlying mechanics. In this study we integrate 3D seismic reflection and borehole data from the Green Canyon Area of the northern Gulf of Mexico, USA to characterize the geophysical and geological expression of a tertiary weld, as well as its broader salt-tectonic context. These data show although it appears complete on seismic reflection data, the weld contains c. 38 m of pure halite. This thickness is consistent with the predictions of analytical models, and with observations from other natural examples of subsurface welds. Our observations also support a model whereby compositional fractionation of salt occurs as the salt-tectonic system evolves; in this model, less mobile and/or denser units are typically stranded within the deeper, autochthonous level, trapped in primary welds, or stranded near the basal root of diapirs, whereas less viscous and/or less dense units form the cores of these diapirs and, potentially, genetically related allochthonous sheets and canopies. We also show that shearing of the weld during downslope translation of the overlying minibasin did not lead to complete welding.
Rock Garden test site – hydraulics in porous fractured media
Authors: Englert Andreas , Bayer Peter
Published: March 2022

Understanding of subsurface flow and transport is of major interest supporting optimal design for several societal relevant technologies, such as waste disposals, geothermal or groundwater production facilities. To advance measurement and modeling techniques and refine them for practical applications, we further developed the fractured aquifer test site Rock Garden at the Martin Luther University Halle. The Rock Garden test site is situated beneath the courtyard of the Faculty of Natural Sciences III and is 60 m x 60 m in size. Fractured Rotliegend series of conglomerates, sand- and siltstones are investigated at the site by 6 drillings. A central borehole (B3) is 40 m in depth and developed as an open borehole between 15 m - 40 m below surface. Five boreholes are developed as groundwater observation wells of about 20 m depth and are equipped with filter screens between 10 m - 20 m below surface. Natural groundwater levels are on average about 3 m below surface and vary about 0.5 m around this value. The average gradient varies as a function of time between 0.3 % and 0.5 %, direction east northeast. A first pumping test in B3 unraveled hydraulic connection to all of the five surrounding boreholes. The effective transmissivities are of the order of 10-5 m2/s and storativities are of the order of 10-4. To understand hydraulically active fractures or fracture zones and their connection to the rock matrix at the Rock Garden site, a first flowmeter experiment was performed in well B3. Under natural conditions no flowmeter signals have been detected suggesting vertical ambient flow to be smaller than 7 cm/min. Under pumping conditions, the flowmeter signals suggest diffuse horizontal inflow from conglomerate lenses (about 80 % of the total inflow) and discrete horizontal inflow from fractures in clay and siltstones (about 20 % of the total inflow). To characterize these fractured and porous zones in detail, we plan performing hydraulic and tracer tomography at the Rock Garden test site in the near future.
Projected increases in climate extremes and temperature-induced drought over the Peruvian Andes, 1980-2100
Authors: Potter Emily , Fyffe Catriona , Orr Andrew , Quincey Duncan , Ross Andrew N , Rangecroft Sally , Medina Katy , Burns Helen , Llacza Alan , Jacome Gerardo , Hellström Robert , Castro Joshua , Hosking J Scott , Cochachin Alejo , Klein Cornelia , Loarte Edwin , Pellicciotti Francesca
Published: March 2022

Precipitation, snow and ice melt from Andean river basins provide a crucial water source to mountain and downstream communities equally. Precipitation and temperature changes due to global climate change are likely to affect agriculture, hydropower generation and hazard risks, but are poorly constrained, especially in future projections.

Here we focus on two heavily glacierised regions of the Peruvian Andes, the Cordillera Blanca, and the Cordillera Vilcanota-Urubamba, to assess projected changes in extreme meteorological events and droughts. Previous work suggests increasing temperatures in both regions in the 21st century, with contrasting projections of precipitation trends. There has been little focus, however, on how extremes in precipitation and temperature might vary in the future. Having created a bias-corrected regional climate model from 1980-2018, we use empirical quantile mapping to statistically downscale 30 CMIP5 models. This ensemble is analysed to determine future changes in climate extremes.  

Both minimum and maximum daily temperatures are projected to increase in the from 2018 to 2100. This leads to a large reduction in the number of frost days in both regions, and suggests that under a high-emissions scenario, almost every day in the late 21st century will be in the 90th percentile of temperatures experienced during 1980-2018. The number of wet and dry days is not projected to change, but precipitation falling on very wet days (in the 95th percentile of the 1980-2018 period) is projected to increase significantly.

Lastly, we consider changes in future meteorological droughts using the standardised precipitation evapotranspiration index (SPEI) which considers potential evapotranspiration, as well as precipitation. We estimate potential evapotranspiration from temperature projections, using the Hargreaves method. Despite projected precipitation increases, temperature increases leading to an increase in evaporation may be large enough to increase meteorological droughts in the future, with the total number of drought months projected to almost double under high emission scenarios by the end of the 21st century. In a region that already experiences water stress and hazards, these changes to both extreme rainfall and drought could have a significant impact for communities in the Peruvian Andes, and for the downstream urban areas and industry that rely on mountain river flow.

 