bluuebunny/crossref_metadata_2025 huggingface dataset:
Controls on slab detachment and subsequent topography evolution
Authors: Piccolo Andrea , Thielmann Marcel
Published: March 2022

Slab detachment causes a reorganization of the forces acting on orogenic systems and can have a distinctive signature in the geological record that may be identified through the structural,  metamorphic and topographic evolution of the orogen. However, this signature is hidden within other signals relating to the general complexity of the mountain building processes. In addition, slab detachment (or slab tearing in 3D) is a complex process that occurs on different timescales as a function of the inherent rheological properties of the lithosphere and the weakening mechanism occurring within the slab (viscous, plastic or thermal weakening).

How these properties affect the slab detachment process and to which extent these controls are reflected in the topograhic evolution of the orogenetic system is not yet fully understood. As slab detachment may occur at different depths and rates, it has different effects on the overall pull force acting on the orogen and on its post-detachment response.

Here, we employ 2D numerical experiments to systematically explore first order controls on slab detachment (slab rheology, geometry and weakening mechanisms) and the corresponding topographic evolution. Apart from the effect of lithosphere rheology and weakening mechanisms, we put particular focus on the effects of plate coupling and breakoff depth.
The effects of terrestrial exoplanet bulk composition on long-term planetary evolution 
Authors: Spaargaren Rob , Ballmer Maxim , Mojzsis Stephen , Tackley Paul
Published: March 2022

The study of exoplanets can provide a more general understanding of planetary systems and terrestrial-planet evolution. How terrestrial exoplanets differ from Earth has so far mostly focused on planet size and orbital distance. In contrast, bulk planet composition has gained much less attention, even though it controls key physical properties of planetary interiors, and thus interior dynamics and long-term evolution. Bulk planet composition is related to core size as well as mantle chemistry and mineralogy. To better understand the variability of interior properties among terrestrial exoplanets, we attempt to constrain the range of bulk terrestrial exoplanet compositions. 

To constrain the compositional range of terrestrial exoplanets, we use the compositional link between rocky planets and their host stars. At least in the Solar System, planetary building blocks (chondrites) correspond to the devolatized star (Sun) composition. Accordingly, we apply devolatilization to stellar compositions in the galactic neighbourhood (i.e., within 500 pc) according to the approach of Wang et al. [1]. These bulk compositions are then split into core and mantle reservoirs by considering interior oxygen fugacity during core formation equal to that of Earth. 

We find compositional ranges of molar mantle Mg/Si-ratios from 0.9 to 2.0, core sizes between 18 and 35 wt%, and mantle molar MgO+FeO+SiO2 abundances between 88 and 94 mol%. We summarize our results by defining 20 end-member compositions that represent the full range of bulk terrestrial exoplanet compositions in the Solar neighbourhood. A Gibbs energy minimization algorithm, Perple_X, shows that these planets all have mantles dominated by Fe-Mg-Si minerals, such as olivine, pyroxene, bridgmanite and periclase. The relative abundances of these minerals control mantle viscosity, where Mg-rich minerals (periclase) are weaker than Si-rich minerals (olivine, bridgmanite). We continue by simulating mantle dynamics using a 2D geodynamic model. Most of our end-member planets have a lower mantle viscosity than Earth, and their mantles are more fertile than Earth's. Accordingly, we find that mantle cooling is more efficient than for Earth for most Earth-sized exoplanets in the solar neighborhood. Future work is needed to further constrain the coupled interior-atmosphere evolution of Earth-like exoplanets, and how bulk planet composition affects it. 

[1] Wang, H.S., Lineweaver, C.H., Ireland, T.R. (2019). The volatility trend of protosolar and terrestrial elemental abundances. Icarus, 328, 287-305 
Analysis of different weighting functions of observations for GPS and Galileo PPP
Authors: Kiliszek Damian , Araszkiewicz Andrzej , Kroszczyński Krzysztof
Published: March 2022

At present, significant development of the positioning methods using the Global Navigation Satellite System (GNSS) can be seen. One of the most developed methods is the absolute Precise Point Positioning (PPP) method. This can be particularly seen using multi-GNSS measurements. The development of multi-GNSS increases the number of satellites observed and increases the accuracy of the products, but also creates new requirements for observation modeling. Obtaining the correct values, ​​of the estimated parameters, requires the appropriate determination of the deterministic model as well as the stochastic model. Currently, the deterministic model is well known. In contrast, the stochastic model is not fully known and still requires a number of studies. Stochastic modeling is based on determining the covariance matrix and which can be modeled using a weighting function that takes into account the elevation angle of the observed satellite. ​

In our analysis, we focus on studies on the weighting functions of GNSS observations for the PPP method. Analysis was performed on the Multi-GNSS Pilot Project (MGEX) stations which were characterized by global distribution and various equipment in 2021. Studies were conducted for the GPS‑only, Galileo-only, and GPS+Galileo constellations, with particular emphasis on the Galileo observations, which has achieved significant progress in recent years. Eight different observation weighting models have been selected for analysis: one of them assumes that all observations have the same precision, without dependence on the elevation angle; for the other used functions, the observation precision value depends on the elevation angle. Parameters such as accuracy, convergence time, zenith path delay (ZPD), and inter-system bias (ISB) are analyzed.

Based on the tests performed, we show that, depending on the solutions adopted (i.e. GPS-only, Galileo-only, GPS+Galileo), the best results were obtained for different weighting functions. We have shown that using different weighting functions have no impact on the horizontal component but a visible impact on the vertical component,  the tropospheric delay, and the convergence time. Also, we choose the best functions for GPS-only and Galileo-only and used them for the GPS+Galileo solution. For this new approach obtained a shorter convergence time and higher accuracy of the ZPD. More information and results will be presented at the conference.
Pre-vegetation, single-thread rivers sustained by cohesive, fine-grained bank sediments: Mesoproterozoic Stoer Group, NW Scotland
Authors: Valenza Jeffery , Ganti Vamsi , Whittaker Alexander , Lamb Michael , Fischer Woodward
Published: March 2022

Evidence of an enigmatic and unidirectional shift in fluvial architecture coincides with the proliferation of early vascular plants in the Silurian period. Unlike post-Silurian fluvial deposits, pre-Silurian fluvial strata lack significant alluvial mudrock and are most often characterized by broad sheet-like sandstones. This sedimentary architecture is traditionally interpreted as a pre-Silurian global prevalence of broad, shallow rivers with unstable channel banks, in stark contrast to the modern-day prevalence of low-sloping, meandering rivers. The Silurian stratigraphic shift has been attributed to the profound influence of vegetation on river geometry. Rooted plants are thought to have dramatically increased channel bank strength, decreased the ability of rivers to rework overbank deposits, and increased mud production rates through enhanced chemical weathering. Recent paleohydraulic reconstructions of pre-Silurian channel-bodies from around the world reveal that deep, single-threaded rivers were likely common during the pre-Silurian period, challenging the traditional paradigm. However, the mechanisms that provided pre-Silurian rivers the necessary bank strength to sustain deep-channeled flows have yet to be quantitatively explored using geologic observations. Here, we integrate recent advances in paleohydrological methods with original and published field data to reconstruct paleohydraulics and channel planforms of Mesoproterozoic fluvial deposits in NW Scotland.

Specifically, we combine geological observations of ~1.2 Ga Stoer Group channel fill deposits in NW Scotland with mechanistic theories that describe the formation of river dunes to quantitatively assess the dominant channel planform style. Our results indicate that Stoer Group fluvial strata represent formative channels with 2-6 meters bankfull flow depth and bed slopes ranging from 6x10-5-2x10-3. We combine these estimates with measurements from modern channels to show that the Stoer Group rivers plot alongside modern single-thread, meandering rivers and high-sinuosity, wandering rivers in a quantitative channel-planform discriminant space. Furthermore, using a mechanistic theory that describes the formation of single-threaded rivers without plants, we show that the deep Stoer Group rivers could have been sustained by the cohesive bank strength provided by mixed siliciclastic sediments with 25-40% mud content—a range consistent with field observations of mud content in putative floodplain facies of the Stoer Group. Finally, we relate our findings to modern environments by considering width to depth ratios and bank cohesion thresholds in a large set of modern rivers, showing that only a small fraction of global rivers requires vegetation to maintain bank stability.
Nitrous oxide dynamics on the Siberian Arctic Ocean shelves
Authors: Wild Birgit , Ray Nicholas , Lett Céline , Davies Amelia , Kirillova Elena , Holmstrand Henry , Klevantceva Elizaveta , Osadchiev Alexander , Gangnus Ivan , Yakushev Evgeniy , Kosmach Denis , Dudarev Oleg , Gustafsson Örjan , Semiletov Igor , Brüchert Volker
Published: March 2022

Nitrous oxide (N2O) is a strong greenhouse gas and a major ozone depleting agent. Almost a quarter of global N2O emissions stems from the ocean, but projections of future releases are uncertain due to scarce observations over large areas and limited understanding of the drivers behind. Here, we focus on the vast continental shelf seas north of Siberia, a hotspot area of global change that experiences rapid warming and high nitrogen input via rivers and coastal erosion; yet N2O measurements from this region are extremely scarce. We combine water column N2O measurements generated during two expeditions with on-board incubation of intact sediment cores to fill this observational gap, constrain N2O sources and assess the impact of land-derived nitrogen that is expected to increase with permafrost thaw. Our data show elevated nitrogen concentrations in the water column and sediments near the mouths of large rivers, suggesting that land-derived nitrogen might promote primary production, but also nitrification and denitrification in the region. However, N2O concentrations were only weakly influenced by elevated nitrogen availability near river mouths. Comparison with a range of environmental parameters suggests that N2O concentrations might be controlled by interactions of nitrogen availability with turbidity and possibly temperature. Surface water N2O concentrations were on average in equilibrium with the atmosphere, but high spatial variability indicates strong local N2O sources and sinks. Water column profiles of N2O concentrations and low sediment-water N2O fluxes do not support a dominant sedimentary source or sink, but point at production and consumption processes in the water column as main drivers of N2O dynamics in the Siberian shelf seas. The projected increases in water temperature and input of freshwater, nitrogen and suspended material from rivers and coastal erosion with land permafrost thaw have the potential to affect not only net N2O production rates, but also N2O solubility in the water, and increase N2O emissions from the Arctic Ocean.
On the wave boundary layer above wind waves: influence of surfactants
Authors: Schultz Katja , Gade Martin , Buckley Marc P. , Tenhaus Janina
Published: March 2022

This study aims to investigate the wave boundary layer and the turbulent
airflow above wind waves on slick-free and slick-covered water surfaces. To realize
this, we carried out laboratory measurements of the airflow in a wind-wave
tank, where we deployed three surfactants of different visco-elastic properties,
each at five wind speeds ranging from 4 ms−1 to 8 ms−1. For measurements
over slick-free water surfaces, we chose wind speeds, at which we observed the
same peak wave frequencies as in the presence of the surfactants. We measured
high-resolution single-point profiles of the horizontal and vertical velocity
components at different heights above the water surface using a Laser-Doppler-
Velocimeter (LDV), wave heights using a wire gauge, and wave slopes using
a laser slope gauge. Both wave field parameters were recorded simultaneously
with the airflow measurements to investigate the influences of the small-scale
wave field on the wave boundary layer. In the airflow turbulence spectra, we
found a clear maximum corresponding to the dominant wave frequencies reflecting
the influence of the waves on the airflow. However, depending on wind
speed and the surfactants’ damping behaviour, the maximum differs in both its
strength and its height above the wavy surface, the latter being interpreted as
the wave boundary layer height. The LDV achieved mean data rates exceeding
2 kHz; hence, it resolved the small-scale turbulence, which manifests in the
high-frequency part of the turbulence spectra. For the slick-free cases, we observed
a linear decrease in turbulence with increasing height above the surface,
and increasing turbulence with increasing friction velocity u∗, which depends
on the wind speed and wind-wave interactions. However, we did not find clear
trends at any wind speed when the water surface was covered by a surfactant.
Here, the turbulence increases with increasing height above the water surface for
higher friction velocities. Thus, the surfactants dampen not only the waves, but
they also reduce the turbulence in the airflow directly above the waves, within
the wave boundary layer.
Assessing the geological potential of the Lower Muschelkalk as High Temperature - Aquifer Thermal Energy Storage (HT-ATES) horizon in Berlin (Germany)
Authors: Wenzlaff Christian , Winterleitner Gerd , Virchow Lioba , Regenspurg Simona , Thielke Christoph , Blöcher Guido
Published: March 2022

High Temperature - Aquifer Thermal Energy Storage (HT-ATES) offers a promising opportunity for climate-neutral heat supply in urban areas due to their high storage capacity and the possibility of direct integration into the regional district heating system. The assessment of the storage potential of HT-ATES requires reliable numerical models of the corresponding storage formation. To analyse the potential of the Lower Muschelkalk (Middle Triassic) as HT-ATES horizon, an unstructured 3D finite element model of the natural gas storage facility in Berlin/Spandau was developed. At this site, two porous layers (average porosity of 22 %) of oolithic grainstones characterize the target formation with a total thickness of about 30 m and a natural reservoir temperature of 32 °C in a depth of 535 m below ground surface. Beside lab analysis of core samples and fluid samples from the site, slug-withdrawal tests were performed in summer 2021 to identify hydraulic key parameters for the numerical simulations. The results indicate a productivity between 0.5 and 1.2 l/s/bar with reservoir permeability between 250 and 700 mD allowing maximum flow rates between 55 and 135 m³/h. In this study, we present a complete workflow from geological characterisation, lab analysis and field testing to detailed numerical HT-ATES simulations. Furthermore, we compare the storage potential based on different data sources such as solar heating systems and district heating networks. First results from the numerical simulations with storage volumes between 15,000 m³ (solar heating system) and 400,000 m³ (district heating system) show promising mean efficiency values between 60 % and 90 % within 25 years of operation. The hydraulic tests and the underlying numerical simulations indicate that the Lower Muschelkalk is suitable for HT-ATES.
Predictive properties of an anisotropic ETAS Space-time model applied to Chilean seismicity
Authors: Chiodi Marcello , Nicolis Orietta , Adelfio Giada , Marcon Giulia , Gonzalez Alex , D'Alessandro Antonino
Published: March 2022

Seismic activity can be often described by a space-time ETAS (Epidemic Type Aftershock Sequences) model, which is composed of a background seismicity component (large scale) and a triggering one (small scale). Typically the large-scale component is a spatial inhomogeneous Poissonian process, whose intensity is usually estimated through non-parametric techniques: in the case of Chilean seismicity, the majority of events, with a greater magnitude, occur along the Nazca plate, due to the subduction process, so that the  anisotropic kernel estimates should better describe the background seismicity than the classical isotropic kernel estimates. Similar considerations could be made for triggered events.
In previous papers, we used the ETAS model, with the Forward Likelihood Predictive approach (FLP), with the triggered seismicity modeled with a parametric space-time function, using also some covariates together with the magnitude of the triggering events. From a statistical point of view, a forecast of triggered seismicity can be made in the days following a big event. In this work, we will explore the predictive properties of a new proposal of anisotropic ETAS model, with an extension of the semiparametric approach of etasFLP proposed by Chiodi, et al. (2021).
We used open-source software (R package etasFLP, Chiodi and Adelfio 
(2017, 2020)) to perform the semiparametric estimation of the ETAS model with covariates.

 
NO3 radical initiated oxidation products of Δ-3-carene: Characterization and mechanism of formation
Authors: Li Linjie , Mark Salvador Christian , Priestley Michael , Tsiligiannis Epameinondas , Hallquist Mattias
Published: March 2022

A series of experiments of NO3 radical initiated oxidation of monoterpenes (C10H16) were conducted using an oxidation flow reactor (Go:PAM) combined with an iodide high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS). This study characterized the major organonitrate products from NO3 radical initiated oxidation of Δ‑3-Carene with various levels of oxidation, i.e. by increasing the concentration of NO3. C10 monomers (products with 10 carbons) are generally the dominant products of Δ‑3-carene (e.g. C10H15NO7 and C10H17NO5); but where higher oxidant levels enhance fragmentation. In comparison to α-pinene, the  Δ‑3-carene oxidation has a higher propensity to create low volatile species, i.e. promote aerosol formation, mechanistically explained by difference in alkoxy radical (RO) bond scissions. A kinetic model (using FACSIMILE) was developed to simulate the formation of dominant products. The mechanism was based on analogue systems within the Master Chemical Mechanism (MCM) and recently available literature. The fate of RO2 under different chemical regimes was also investigated by comparing model runs and the experimental results.
Continuous measurement of Mg/Fe and Ca/Na ratios with scanning Laser Induced Breakdown Spectroscopy in 6 meter of drill core through Merensky Reef, Bushveld Complex, South Africa 
Authors: Meima Jeannette , Rammlmair Dieter , Junge Malte , Nikonow Wilhelm
Published: March 2022

A 6-meter drill core from Merensky Reef, Bushveld Complex, South Africa, was scanned in detail with a drill core scanner based on Laser Induced Breakdown Spectroscopy (LIBS). The purpose of the investigation was to visualize variations in the chemical composition along the core, and following a mineral classification of the LIBS data, of variations in the mineral chemical composition, e.g. of Fe/Mg, Cr/Al, and Ca/Na ratios, as well.

The LIBS technology is based on atomic emission spectroscopy, in which the excitation of the atomic species occurs in-situ on the sample surface. The excitation source was a pulsed 50 mJ 1064 nm Nd:YAG laser, and the emitted light was collected with a high-resolution wide-range echelle spectrograph with CCD detector. This approach for measuring mineral chemical ratios such as Mg/Fe, Cr/Al, and Ca/Na, is based on the strength of LIBS in detecting chemical variations using intensity ratios within a single matrix, which in this application is one single particular type of mineral phase. For validation purposes, selected samples were analysed with bulk chemical analysis and electron probe microanalysis as well.

Distinct trends could indeed be extracted from the 6 m core section through the Merensky Reef. From a saw-cut core surface without further preparation, a continuous record could be extracted consisting of Mg/Fe of orthopyroxene, Ca/Na of plagioclase, bulk chemical patterns, modal composition, and direct neighbourhood. The data can be used to highlight the presence of unusual patterns and to relate them to Ni, Cu, PGE or other mineralization. When applied to different core sections, it may become an important tool for comparing lateral variability of diagnostic horizons in vertical sequences in layered intrusions such as Merensky Reef and UG-2.
Cross-Country Risk Quantification of Extreme Wildfires in Mediterranean Europe*
Authors: Meier Sarah , Strobl Eric , Elliott Robert J.R. , Kettridge Nicholas
Published: March 2022

 We estimate the country-level risk of extreme wildfires defined by burned area (BA) for Mediterranean Europe and carry out a cross-country comparison. To this end we avail of the European Forest Fire Information System (EFFIS) geospatial data from 2006-2019 to perform an extreme value analysis. More specifically, we apply a point process characterization of wildfire extremes using maximum likelihood estimation. By modeling covariates, we also evaluate potential trends and correlations with commonly known factors that drive or affect wildfire occurrence, such as the Fire Weather Index as a proxy for meteorological conditions, population density, land cover type, and seasonality. We find that the highest risk of extreme wildfires is in Portugal (PT), followed by Greece (GR), Spain (ES), and Italy (IT) with a 10-year BA return level of 50'338 ha, 33'242 ha, 25'165 ha, and 8'966 ha, respectively. Coupling our results with existing estimates of the monetary impact of large wildfires suggests expected losses of 162-230 million € (PT), 81-96 million € (ES), 41-126 million € (GR), and 18-34 million € (IT) for such 10-year return period events.
Minimalistic approach to planetary cloudiness
Authors: Datseris George , Blanco Joaquin , Bony Sadrine , Caballero Rodrigo , Hadas Or , Kaspi Yohai , Stevens Bjorn
Published: March 2022

Understanding planetary cloudiness is of major importance for Earth's energy balance and potential for warming, but so far we lack pathways to approach planetary cloudiness theoretically. On the one hand, it is difficult to connect the microphysics of cloud formation to planetary wide cloudiness. On the other hand, a representation of cloudiness in energy balance models simply does no exist yet. In this work we want to provide simple means to treat planetary cloudiness in an energy balance model. We utilize a top-down approach and directly decompose the energetic signature of planetary cloudiness into a simple model composed of simple components. Vertical wind speed and estimated inversion strength are enough to capture all major characteristics of cloudiness in both shortwave and longwave spectral signatures. Other variables provide only minor improvements to the fits, while surface horizontal wind speed seems to be important for capturing hemispheric asymmetries in cloudiness. We use our results to argue that cloudiness can be incorporated into conceptual models based on mean temperature and equator-to-pole temperature difference.
Global maps from local data: Towards globally applicable spatial prediction models
Authors: Ludwig Marvin , Moreno Martínez Álvaro , Hölzel Norbert , Pebesma Edzer , Meyer Hanna
Published: March 2022

Global-scale maps are an important tool to provide ecologically relevant environmental variables to researchers and decision makers. Usually, these maps are created by training a machine learning algorithm on field-sampled reference data and the application of the resulting model to associated information from satellite imagery or globally available environmental predictors. However, field samples are often sparse and clustered in geographic space, representing only parts of the global environment. Machine learning models are therefore prone to overfit to the specific environments they are trained on - especially when a large set of predictor variables is utilized. Consequently, model validations have to include an analysis of the models transferability to regions where no training samples are available e.g. by computing the Area of Applicability (AOA, Meyer and Pebesma 2021) of the prediction models.

Here we reproduce three recently published global environmental maps (soil nematode abundances, potential tree cover and specific leaf area) and assess their AOA. We then present a workflow to increase the AOA (i.e. transferability) of the machine learning models. The workflow utilizes spatial variable selection in order to train generalized models which include only predictors that are most suitable for predictions in regions without training samples. We compared the results to the three original studies in terms of prediction performance and AOA. Results indicate that reducing predictors to those relevant for spatial prediction, leads to a significant increase of model transferability without significant decrease of the prediction quality in areas with high sampling density.

Meyer, H. & Pebesma, E. Predicting into unknown space? Estimating the area of applicability of spatial prediction models. Methods in Ecology and Evolution 2041–210X.13650 (2021) doi:10.1111/2041-210X.13650.
An integrated UAS and TLS approach for monitoring coastal scarps and mass movement phenomena. The case of Ionian Islands.
Authors: Diakakis Michalis , Vassilakis Emmanuel , Mavroulis Spyridon , Konsolaki Aliki , Kaviris George , Kotsi Evangelia , Kapetanidis Vasilis , Sakkas Vassilis , Alexopoulos John D. , Lekkas Efthymis , Voulgaris Nicholas
Published: March 2022

Mediterranean tectonically-active coastal areas are a highly-dynamic environment balancing internal tectonic dynamics with external geomorphic processes, as well as manmade influences. Especially in touristic areas characterized by high built-up pressure and land value, where these dynamics are even more concentrated, the evolution of coastal environments needs careful and high-resolution study to identify localized risk and the processes they derive from.
Recently, new advanced remote sensing techniques such as Unmanned Aerial Systems (UAS)- and Terrestrial Laser Scanners (TLS)-aided monitoring have improved our capabilities in understanding the natural processes and the geomorphic risks (i.e. mass movement phenomena).
An integrated study comprising Unmanned Aerial Vehicles (UAV) and Light Detection And Ranging (LIDAR) sensors was conducted in coastal areas of the southern Ionian Islands (Western Greece) aiming to the mitigation of earthquake-triggered landslide risk and to responsible coastal development. Located at the northwesternmost part of the Hellenic Arc, this area is characterized by high seismicity and has been affected by destructive earthquakes mainly due to the Cephalonia Transform Fault Zone (CTFZ), which constitutes one of the most seismic active structures in the Eastern Mediterranean region. One of the most common environmental effect triggered by these earthquakes are landslides distributed along fault scarps in developed and highly visited coastal areas. Furthermore, this area is highly susceptible to hydrometeorological hazards inducing intense geomorphic processes, including Medicanes among others.
These technologies allow a highly-detailed view of landslide processes, providing insights on the structures and factors controlling and triggering failures along coastal scarps as well as highlighting susceptible zones and high-risk areas with accuracy and mitigating adverse effects with precision and clarity. Overall, by providing a better understanding of the risks the approach used allows a more sustainable development of these coastal segments enhanced by risk mitigation.
The study was conducted in the framework of the project “Telemachus - Innovative Operational Seismic Risk Management System of the Ionian Islands”, co-financed by Greece and the European Union (European Regional Development Fund) in Priority Axis “Environmental Protection and Sustainable Development” of the Operational Programme “Ionian Islands 2014–2020”.
Hydrological restoration of an upland peatland and its consequences for the microbial processing of dissolved organics
Authors: Ring-Hrubesh Fin , Welch Bradley , Gallego-Sala Angela , Johnes Penny , Pancost Richard , Bryce Casey
Published: March 2022

Peatland restoration efforts are accelerating globally with a primary aim of restoring the carbon balance of these ecosystems. Degraded peatlands export carbon to the atmosphere but also to freshwater environments as dissolved organic compounds. Whilst hydrological restoration measures can effectively reduce emissions of CO2 from upland peatlands, the impact on carbon export to the aquatic environment is less apparent. In some cases, dissolved organic concentrations can even increase after restoration, without clear mechanisms that could drive such a response. We aim to determine whether the response of the peat microbial community to restoration measures can explain poorly understood trends in dissolved organics. 

We investigated a severely degraded peatland in South Wales that has experienced historic drying to considerable depth, almost complete loss of surface vegetation, and a lowering of the peat surface. Restoration measures implemented over the past 16 years have involved hydrological intervention through gulley-blocking as well as efforts to stabilize the peat surface and re-establish plant communities.  Porewater collected over the first 6 months of our investigation indicates, contrary to expectation, that DOC concentrations were lowest in the most severely degraded region of the bog and highest in the least disturbed regions. We will discuss the potential drivers behind this observed trend, focusing on the role played by the peatland microbiome in the processing of dissolved organics in the peatland. In addition, we draw on water-table monitoring and sampling results to consider how environmental and geochemical conditions moderate biotic processing of dissolved organics. Improvement of our understanding of the microbial community response to rewetting measures is required as this underpins the function and carbon balance of these systems and will ultimately inform management approaches. 
Global gravity gradient inversion reveals variability of cratonic crust
Authors: Haas Peter , Ebbing Jörg , Szwillus Wolfgang
Published: March 2022

In this contribution, we present a global estimate of crustal thickness with emphasis to cratons. In an inverse scheme, satellite gravity gradient data are inverted for the Moho depth, exploiting laterally variable density contrasts based on seismic tomography. Our results are constrained by an active source seismic data base, as well as a tectonic regionalization map, derived from seismic tomography. For the global analysis, we implement a moving window approach to perform the gravity inversion, followed by interpolating the estimated density contrasts of common tectonic units with a flood-fill algorithm.

The estimated Moho depth and density contrasts are especially interesting for the cratons of the Earth. Our results reveal a surprising variability of patterns with average Moho depth between 32-42 km, reflecting an individual tectonic history of each craton. Statistical patterns of Moho depth and density contrasts are discussed for the individual cratons and linked to their stabilization age. For example, Australia shows the lowest average Moho depth (32.7 km), indicating early stabilization in the Archean and removal of a dense lower protocrust. This observation matches well with receiver function studies. The globally inverted Moho depth is validated by gridded seismic Moho depth information, which shows that for many cratons the inverted Moho depth is within expected uncertainties of the seismic Moho depth. In addition, the formerly connected cratons of South America and Africa are analyzed and discussed in a Gondwana reconstruction. Here, the once-connected West African and Amazonian Cratons have a shallow Moho depth, indicating that only little tectonic activity occurred during the Phanerozoic. The tectonically-linked Congo and Sao Francisco Cratons have intermediate Moho depths, with the Congo Craton having a slightly shallower Moho depth. This could reflect dynamic support of the upper mantle on the African side.
Super-resolution total suspended matter and chlorophyll concentration using Sentinel-2 and Sentinel-3 data.
Authors: Alvera-Azcárate Aida , Van der Zande Dimitry , Barth Alexander , Beckers Jean-Marie
Published: March 2022

Coastal ocean areas are very dynamic regions subject to strong anthropogenic pressure (e.g. industry, tourism, renewable energies, population). Satellite data constitute a unique tool that allows one to study and monitor these areas at a unique spatial and temporal resolution. The spatial and temporal scales needed to assess changes at coastal regions are higher than what can be rendered by individual missions: for example, satellites like Sentinel-3 provide daily temporal resolution, but the sensors onboard these satellites do not measure at the necessary high spatial resolution to resolve complex coastal dynamics; on the other hand, high spatial resolution sensors, like MSI onboard Sentinel-2 (10 m resolution), are able to resolve these small scales, but with a low temporal revisit time (about 5 days). Both high spatial resolution datasets and traditional ones are hindered by the presence of clouds, resulting in a large amount of missing data. The complementarity of Sentinel-2 and Sentinel-3 datasets can be exploited to derive a super-resolution dataset of total suspended matter and chlorophyll concentration in the Belgian coast (North Sea), with the spatial resolution of Sentinel-2 and the temporal resolution of Sentinel-3. Moreover, as the approach used is based in DINEOF (Data Interpolating Empirical Orthogonal Functions), missing data can be interpolated as well, to provide a gap-free super-resolution dataset retaining the spatial scales of the highest resolution dataset (Sentinel-2 in this case). The influence of ocean dynamics in the region will be assess using these ocean colour variables.

 
Assessing Deformation Monitoring Systems For Supporting Structural Rehabilitation under Harsh Conditions
Authors: Neuner Hans , Kostjak Victoria , Linzer Finn , Loderer Walter , Seywald Christian , Strauss Alfred , Rigler Matthias , Polt Markus
Published: March 2022

This paper deals with the evaluation of four measuring systems for the detection of potential deformations that can occur during structural rehabilitation measures. For this purpose, a test object resembling the shape of a tunnel structure was constructed. The structural properties of this test object are discussed in the related paper by Strauss et. al submitted for the same session.

In the paper, the installed measuring systems are presented first. These are a lamella system based on fibre optics, an array of accelerometers, a digital image correlation system and a profile laser scanner based system. The operating principles of the systems are briefly introduced.

A long-term measurement on the object in an unloaded state, which extended over several weeks, enables statements about the capturing of temperature-related deformations, the temperature dependence of the measured values and drift effects of the investigated systems. Selective loading of the test object was generated via four screw rods and applied both in the elastic as well as in the plastic deformation range. This enabled knowledge gain regarding the precision and the sensitivity of the analysed measuring systems.

Environmental conditions may have a strong influence on the measurement values. The former can be determined by permanent installations on the structure and its operating conditions as well as by the undertaken rehabilitation measures. Representative for the first category we investigated the influence of magnetic fields and light conditions on the measuring systems. For the second category, strong dust formation and increased humidity were generated during a test procedure.

An assessment regarding data handling, including storage, transfer and processing, completes the investigation of the four measuring systems. A summarising evaluation concludes the article.
Predicting the land ice contribution to sea level rise with Gaussian process emulation
Authors: Turner Fiona , Edwards Tamsin
Published: March 2022

Changes in the cryosphere are the leading component of global sea level rise. There is great uncertainty in what these changes will look like in the coming centuries, partly due to the unknown effects of the climate and ice sheet models used to model these changes. Modelling these contributions are necessary to understand how coastal communities and low-lying states will be affected by climate change; in order to do this, and to quantify the inherent uncertainties to make more informed estimates, statistical methods are required.

 

Here we describe our work building on Edwards et al. (2021) in the use of Gaussian process emulators to predict the land ice contribution to future sea level rise. Rather than building an emulator of an ensemble of ice sheet models, we emulate each model individually, allowing us to better understand the inherent biases and internal variability within each model. We then compare our combined estimates with our previous results to test how treating each model individually affects our predictions. 

 

We predict changes for different Shared Socioeconomic Pathways (SSPs), to investigate how different future levels of greenhouse emissions will affect sea level rise this century. We also explore differences in sensitivity of the models to different inputs, building a range of sea level predictions. In particular, sensitivity to the basal melt parameter in Antarctica has a significant effect on the upper tail of our distributions; further analysis of other inputs will also be explored. 
First calibration of the physics-based ground motion model of the 2019 Mw4.9 Le Teil earthquake (France)
Authors: Lehmann Fanny , Gatti Filippo , Bertin Michaël , Clouteau Didier
Published: March 2022

The seismic risk in France, a region of low to moderate seismicity, is of paramount importance given the large number of industrial and nuclear installations. However, the large uncertainties on the geology and the poor knowledge of active faults make the seismic hazard estimation a challenging task. Despite being a promising tool to explore the underlying uncertainties, numerical simulations must be duly calibrated by reproducing specific events.

In this work, we considered the 2019 Mw4.9 earthquake that occurred at Le Teil village in southern France. This event was recorded by 17 stations of 3-component accelerometers, within an area of 50 km around the epicenter (French Accelerometric Network). We used these records to calibrate the numerical simulation. The seismological P- and S-wave speed profiles used result from a 3D weighted average model for Metropolitan France. In addition, the topography was included in the spatial discretization. The uncertainties on dip, strike, and rake angles were explored in order to calibrate the far-field synthetic ground motion model by determining the eigenquakes that efficiently span a large diversity of sources.

A good agreement between synthetic and recorded time histories was found, despite the simplicity of the geological and source model.
ARROW (AtmospheRic InfRasound by Ocean Waves): a new real-time product for global ambient noise monitoring.
Authors: De Carlo Marine , Accensi Mickaël , Ardhuin Fabrice , Le Pichon Alexis
Published: March 2022

Between 0.1 and 0.6 Hz, the coherent ambient infrasound noise is dominated worldwide by signals originating from the ocean, the so-called microbaroms. With an energy peaking around 0.2 Hz, microbaroms signals are generated by second order non linear interactions between wind-waves at the ocean surface and are able to propagate all around the globe through the stratosphere and thermosphere. Monitoring these signals allows characterizing the source activity and probing the properties of their propagation medium, the middle atmosphere, assuming that the source is well modelled. A new theoretical description of the mechanism signal generation connecting the amplitude of the pressure signal to the height and frequency wave oscillation has been proposed by De Carlo et al. (2020). This model has been evaluated quantitatively through systematic comparisons with worldwide observations (De Carlo et al., 2021). This model has been implemented by the Laboratoire d’Océanographie Physique et Spatiale (LOPS) research unit of IFREMER in the DATARMOR HPC center (11088 cores - 426 Tflops) which allows big data hosting and intensive computation. We present a technical overview of the ARROW product and its implementation framework for both hindcast and real-time production. In the context of the future verification of the Comprehensive nuclear Test Ban Treaty (CTBT), ARROW offers an opportunity to target infrasonic signals of specific interest interfering with the global ambient coherent noise. This product, based on a state-of-the-art numerical wave model, paves the way for improved medium-range weather forecasting, by building a global and time-dependent reference database used as input to develop innovative remote sensing methods. 
Is the Brewer-Dobson circulation increasing or moving upward? A definitive answer.
Authors: Šácha Petr , Zajíček Radek
Published: March 2022

The meridional overturning mass circulation in the middle atmosphere, i.e. the Brewer- Dobson circulation (BDC), was first discovered before decades based on the distribution of trace gases and a basic analytical concept of BDC has been derived using the transformed Eulerian mean equations. Since then, BDC is usually defined as consisting of a diffusive part, and an advective, residual mean circulation.

Climate model simulations robustly show that the advective BDC part accelerates in connection to the greenhouse gas induced climate change and this acceleration dominates the middle atmospheric changes in climate model projections. A prominent quantity that is being studied as a proxy for advective BDC changes is the net tropical upwelling across the 70 hPa, which measures the amount of mass advected by residual circulation to the stratosphere and upwards.

Another robust aspect of the changes in greenhouse gas concentrations is the changing structure of the atmosphere across layers. Particularly, it was debated whether the increasing BDC is not driven by the vertical shift of the circulation. In our research, we give a complete and definitive answer to this question. We developed an analytical method that allows us to attribute the changes in tropical upwelling to kinematic causative factors such as increasing residual mean vertical mass flux, vertical shift of the circulation and for the first time, changes in width of the upwelling region and changing curvature of the 70hPa level. Our results demonstrate that this is the complete set of kinematic factors influencing the net upwelling and that all of these factors are important contributions to the net upwelling change.

 
Evaluating beach wrack decay through the seasons under wet (underwater) and changing (wet/dry) conditions at the Baltic Sea coast
Authors: Schätzle Philipp-Konrad , Schubert Hendrik
Published: March 2022

Beach wrack, defined as material washed ashore by wind, waves and tides, is a natural phenomenon observed at all coasts worldwide. Often seen as a nuisance and being removed at recreational beaches, it is an important component for dune vegetation succession and habitat for beach faunal components both being negatively impacted by beach management practices. In order to balance the conflicting interests of tourism and nature protection, sound data about amounts, seasonality and composition of beach wrack washed ashore as well as residence time and decomposition kinetics are required, but not available yet for microtidal Seas as the Baltic.

The decay of beach wrack at the beach and under controlled and dry conditions was investigated in the past several times. In this work, the decay of beach wrack, and i.e. seagrass of the genus Zostera marina was documented under natural conditions. Therefore, litterbags of fine mesh were sewed and filled with a defined amount of freshly detached seagrass from the local shore. Altogether six experiments were carried out: first two experiments starting in summer or winter, respectively, with constant wet conditions in appx. 1 m water depth. The remaining four experiments were conducted throughout the four seasons. Here, the litterbags were put into water, removed onto land, and vice versa for a total time period of six weeks. The experiments were run in the shallow water at the island of Poel completely submerged and, for a comparison with changing conditions between water and land, at the beach of Warnemünde. Additionally, the experiments were split between light and dark conditions by the use of different mesh colors.

Data about degradation rate through loss of biomass have been retrieved, as well as abiotic parameters influencing the rate of decomposition. For additional insights into the decay of seagrass each sampling time the biofilm was removed, DNA extracted and analyzes of the microbial biofilm are at an initial stage. This work will give valuable information on the degrading community, the influence of seasons, temperature, light availability and the continued change when beach wrack is washed ashore and retrieved back by the sea for many times through all decomposition stages.