bluuebunny/crossref_metadata_2025 huggingface dataset:
Do diapirs ever lose their heads? Insights from the Romanian Eastern Carpathians
Authors: Tamas Dan Mircea , Tamas Alexandra , Barabasch Jessica , Rowan Mark , Schleder Zsolt , Krezsek Csaba , Urai Janos
Published: March 2022

Numerous orogenic fold-and-thrust belts contain salt. It serves as an excellent décollement for folds and thrusts, and in some, diapirs had a profound influence on the structural styles. In salt-detached fold-and-thrust belts, decapitated diapirs can form due to thrusting but are poorly documented in the subsurface and not reported in outcrop. Here we present a surface exposure of a sub-horizontal intra-salt shear zone, which is interpreted to have formed as a result of partial decapitation of a deep-rooted salt-cored anticline. The Mânzălești diapir in the Romanian Eastern Carpathians forms the largest rock salt outcrop in Europe, with unique salt-karst geomorphology between the Tarcău and Subcarpathian nappes. Numerous wells show that the outcrop lies over a deep-seated salt diapir, the base of which is at >3500 m. Multi-scale observations using UAV-based digital outcrop models, fieldwork, and microstructure analysis show that the outcrop is characterised by sub-horizontal foliation with isoclinal folds. The halite is rich in clastic inclusions, with a power-law size distribution caused by tectonic reworking of originally dirty salt. Microstructures show that the halite matrix is strongly deformed by dislocation creep, forming subgrains with a dynamically recrystallised grain size of about 1.5 mm. This is indicative of relatively high differential stress, of around 4 MPa. After combining observations on all scales (cross-sectional, outcrop, and microstructural analyses), our preferred explanation is that the Mânzălești diapir has evolved from a salt-cored anticline to a thrusted diapir in front of the Tarcău nappe. Intense shear originating from a thrust partially decapitated the diapir, shifting its upper portion away from its base.
Orbit, clock and attitude analysis of QZS-1R
Authors: Steigenberger Peter , Hauschild André , Montenbruck OIiver
Published: March 2022

More than ten years after the launch of the first satellite of the Japanese Quasi-Zenith Satellite System (QZSS), a replenishment satellite for this spacecraft was launched into inclined geo-synchronous orbit (IGSO) in October 2021. Triple-frequency signal transmission of QZS-1R started on November 14, 2021. In the same month, Cabinet Office, Government of Japan published satellite metadata of QZS-1R including mass, center of mass coordinates, laser retro-reflector offsets, satellite antenna phase center offsets and variations, transmit power, attitude law, as well as spacecraft dimensions and optical properties.

Precise orbit and clock parameters of QZS-1R are estimated with the NAPEOS software. The performance of a box-wing model derived from the satellite metadata is evaluated by day boundary discontinuities, orbit overlaps as well as Satellite Laser Ranging residuals. The analysis of the QZS-1R clock parameters estimated together with the orbits is complemented by a one-way carrier phase clock analysis of selected GNSS receivers connected to highly stable clocks in order to study also the short-term clock behavior.

Like previous QZSS IGSO satellites, QZS-1R transmits the L1 Sub-meter Level Augmentation Service (SLAS) via a dedicated antenna separated about 1.2 m from the main navigation antenna. Therefore, simultaneous observations of, e.g., the L1C/A and the L1 SLAS signals allow to determine the QZS-1R attitude. Attitude estimates from a regional network of eight stations are presented and compared to the nominal attitude of the spacecraft.
Deglaciation timing in the Atlantic Iberian mountains: an example from lake sediments in Serra da Estrela (Portugal)
Authors: Hernández Armand , Santos Ricardo N. , Rodrigues Teresa , Oliveira Dulce , Naughton Filipa , Moreno João , Raposeiro Pedro , Giralt Santiago , Sáez Alberto , Leira Manel , Gil-Romera Graciela , Costa Pedro , Trigo Ricardo M. , Vieira Gonçalo , Abbott Mark , Griffore Melissa , Gomes Sandra , Ramos Alexandre M.
Published: March 2022

The Serra da Estrela range in Central Portugal is a key  region to explore the Last Glacial termination in the Atlantic region of Iberia. We present the Late Glacial and Holocene record of Lake Peixão to reconstruct past environmental and climatic conditions at decadal timescales. We retrieved an 8.5m long core in the central and deepest zone of the lake. From the base to the top, the sediment core is composed of i) a thick layer (aprox. 0.5 m) of gravel-to-sand quartz clasts; ii) an alternation of one meter thick grey to pale-brown sandy deposits; and iii) homogeneous dark brown and pale-brown organic-rich muddy facies (ca. 7 meters). Using a Bayesian statistical model based on 16 radiocarbon dates using pollen concentrated samples and 210Pb measurements, we have developed an age-depth model covering the last ca. 14.6 ka, recording the onset of the lake at that time. Lake and mire records previously published in the area generally support this chronology for the formation of proglacial lakes. In addition, the proposed timing for the disappearance of the Serra da Estrela glaciers has been based on Cosmic-Ray Exposure dating (in situ cosmogenic 36Cl) of exposed moraine boulders and glacially polished bedrock surfaces. These results indicate that the end of the glacier’s presence in Serra da Estrela occurred at ca. 14.2 ka BP (during the Bølling-Allerød Interstadial). Therefore our results broadly suport the timing of the end of the deglaciation at the Serra da Estrela and highlight the value of lake sedimentary records. Moreover, the availability of last termination and Holocene highly-resolved sediments from Lake Peixão is likely to record very valuable evidence of climatic and environmental changes at decadal timescales extending from the last deglaciation, through the Holocene. This new multi-proxy data of the Lake Peixão sedimentary sequence will enable comparisons to other decadal-resolved records and support further investigations from the Mediterranean Iberian region.
The financial support for this work was possible through the following FCT project: HOLMODRIVE—North Atlantic Atmospheric Patterns Influence on Western Iberia Climate: From the Late Glacial to the Present (PTDC/CTA-GEO/29029/2017).

 
 How much of the surface energy partitioning can be explained by controls imposed by thermodynamics?
Authors: Ghausi Sarosh , Kleidon Axel
Published: March 2022

Natural processes within the Earth system have been shown to organise themselves to achieve a state of thermodynamic optimality. Here we test these physical principles for convective flux exchange within the surface – atmosphere system.  We propose an idealised modelling framework where the convective exchange is conceptualised as the outcome of a heat engine operated between the hotter Earth’s surface and the cooler atmosphere. We use the first and second law of thermodynamics in conjunction with the surface energy balance which give rise to thermodynamic constraints on turbulent flux exchange. This new constraint is associated with the maximum power that can be generated within the heat engine to sustain convective motion. We use daily radiative forcing from NASA-CERES dataset as the input to our approach and estimated the surface energy partitioning on land into turbulent fluxes and emitted longwave radiation. The former is closely related to convective exchange within the atmosphere driving the hydrologic cycling while the latter directly relates to the surface temperature of the Earth.  We compare our estimates of surface temperatures, latent and sensible heat fluxes with observation based datasets and found a very good agreement over land at a global scale. Our findings show that physical principles of thermodynamics alone can explain the surface energy partitioning to a large extent. We further show an application of this approach in removing the cloud radiative effects (CRE) from surface temperatures. We used clear-sky fluxes from the NASA-CERES dataset as a forcing to our thermodynamically constrained energy balance model and estimated "clear-sky" temperatures. These temperatures removes the effect of radiative cooling by clouds on surface temperatures and can be used as useful variable to infer the hydrological sensitivity from observations. Our work implies that thermodynamically constrained idealised models can be used to identify the dominant physical controls on climate system to better understand land-atmosphere interactions and climate sensitivities.
Mathematical modelling of erosive fluidization, flow localization, and formation of pockmarks
Authors: Gupta Shubhangi , Micallef Aaron
Published: March 2022

Pockmarks, the seafloor manifestations of sub-surface fluid flow, play a prominent role in global carbon emissions, subsurface hydrocarbon exploration, regulation/modulation of local biochemistry and ecology, and mechanical stability of marine sediments. Pockmarks have been reported in extremely diverse geological settings worldwide, and are found to exhibit a remarkably wide variability in their shapes, sizes, and structure, which makes their characterization hard, and quantitative analysis even harder. To further add to the complexity, pockmarks are typically found on top of focused flow conduits (called pipes and chimneys) that connect the seafloor with deep seated source rocks, which strongly suggests that formation of pockmarks is inherently linked to the physics of flow localization in the sub-surface. Many conceptual models have been proposed in the recent years to explain the observed pockmarks and seismic pipes and chimneys, but surprisingly few of these have been translated into mathematical and computational frameworks.

To address this gap, we propose a model concept for simulating flow localization and pockmarks formation based on the mechanism of erosive fluidization. The model resolves the changes in sub-surface and seafloor morphology through conservative redistribution of sediment mass due to seepage induced erosion, fluidization, and transport of granular sediment. Through numerical studies, we demonstrate that this model is not only able to simulate the formation of focused flow conduits and pockmarks of different shapes and sizes, but it also makes important predictions regarding the role of intrinsic sediment characteristics (like permeability) vs characteristics of sediment-fluid interactions (like sediment erodibility and flow anisotropy).
Exploring the potential of desalination and aquaponics in the integrated management of arid river basins: the case of the Nile River basin
Authors: Piuri Veronica , Yang Guang , Giuliani Matteo
Published: March 2022

Water scarcity is one of the major challenges of the century. Climate change and population growth are exacerbating this problem, especially in river basins with arid climates such as the Middle East or North Africa, calling for the design of integrated water management strategies to meet competing water demands in interconnected Water-Energy-Food systems. In this work, we explore the potential for integrating innovative technological solutions, namely desalination and aquaponics, into conventional water management measures to mitigate existing tradeoffs. Our approach is demonstrated on the Nile River basin, a paradigmatic example of transboundary river basins where the overexploited traditional water sources cannot fully satisfy the increasing water demands, thus requiring innovative solutions to address this challenge. Here, we first investigate the optimal operation of the major water infrastructures in the basin to explore the tradeoffs between hydropower generation and irrigation supply across Ethiopia, Sudan, and Egypt. Then, we analyse the role of desalination and aquaponics in reducing the Egyptian water demand in the Nile delta and mitigating the existing tradeoffs. Desalination is widely used in many of the Middle East’s countries and offers the possibility to unlock the potential contribution of sea water in meeting the water demand of the coastal region. Aquaponics is a soilless agricultural technique characterized by lower levels of water consumption than traditional techniques. For both desalination and aquaponics, we run an exploratory analysis to understand the key technological parameters influencing the successful uptake of these solutions. Our results aim to demonstrate the effectiveness of integrated management solutions in arid river basins and explore the potential uptake of new technologies for reducing agricultural water demands. These measures contribute in increasing the flexibility of water management strategies in arid areas when coping with water scarcity while improving water quality conditions.
Verification of the pier scour development in the experimental environment
Authors: Gilja Gordon , Fliszar Robert , Harasti Antonija , Adžaga Nikola
Published: March 2022

Experiments conducted in the hydraulic flume provide a controlled flow environment, which often provides means for prompt qualitative investigation of general flow structure. Under the R3PEAT project (www.grad.hr/r3peat), research focus is on the scour at bridge piers protected by the riprap sloping structure – investigated using both physical and 3D numerical model. Experimental data, while constrained by the flume dimensions and the pump capacity, measured with high frequency Vectrino Profiler’s provide detailed insight into turbulence around the structure. Experimental models are set-up as segments of the river extruded from the bathymetric and hydraulic surveys, corresponding to the flume size and selected scaling. Based on the experimental data, 3D numerical model will be calibrated in order to investigate flow conditions for the relevant floods with design return period, exceeding the flume capacity. Physical model therefore must reliably present the prototype bridge, through resulting flow field in the pier vicinity. This paper presents verification of the physical model using field ADCP measurements. ADCP velocities are compared to experimental data on the 4 cross-sections adjacent to the bridge, adapted to the relative flume streamwise orientation. Advantages and disadvantages of the physical model usage as benchmark for numerical model setup are discussed.

Acknowledgments
This work has been supported in part by Croatian Science Foundation under the project R3PEAT (UIP-2019-04-4046).
High-resolution seismic studies of shallow lake Kandrykul (republic of Bashkortostan, Russia).
Authors: Krylov Pavel , Nurgaliev Danis , Kuzina Dilyara , Dautov Airat , Yasonov Pavel
Published: March 2022

Seismoacoustic studies are used to solve a wide range of different tasks, such as studying the bottom of water bodies and bottom sediments, detecting sunken objects, designing various structures (pipelines, port facilities, etc.), estimating the thickness of sapropel deposits, calculating their reserves, etc. In terms of paleoclimatic studies, the importance of such studies is increasing. The study of sediments of continental water bodies allows to get preliminary information about climate changes in the region with a very high resolution. Seismoacoustic profiling allows remote characterization of lake sediments stratigraphy due to the recordings of acoustic waves reflected from the lake bottom and underlying layers. Seismoacoustic studies were conducted to detect bottom sediments and choose the best place for core sampling in Lake Kandrykul (Republic of Bashkortostan, Russia). 

Continuous seismic profiling was applied based on the principle of central beam, which enables remote investigation of the lake bottom structure owing to the recording of acoustic waves reflected from the lake bottom. On this basis, it is possible to establish borders between sediment layers of different physical properties. The seismoacoustic profiling was carried out using specialized complex, designed and manufactured on the base of Kazan Federal University. The complex includes: a source of elastic waves, a receiver, a seismic station, a laptop, a GPS-receiver, an inflatable boat, an electric motor, and power supply elements. The complex enables us to get seismic acoustic sections with vertical resolution at least 15 cm; depth study of various types of lake sediments at least 15 m; geodetic positioning system within several meters. It also provides the digital recording of information. As a source of elastic waves an inductive oscillator "boomer" was used. A storage battery was used as a source of electric power. The GPS receiver was used to coordinate profiles and boat location.

There were obtained 6 high resolution seismic sections. The total length of the profiles was more than 16 km. According to seismic data the depth of the lake is 15 meters. The thickness of bottom sediments is more than 7 m, which indicates the great age of the lake. Thus, the lake is suitable for studying climate changes in the past for this region. On the seismic section, it is clearly seen the moment of the lake formation, when the lake layered sediments began to accumulate.

This study was funded by the Russian Foundation for Basic Research under the grant #20-05-00833. Part of the study was funded with the subsidy allocated to the KFU in context of state assignment # 671-2020-0049.
Modeling the impact of contemporary ocean stratification changes on the global M2 tide
Authors: Opel Lana , Schindelegger Michael
Published: March 2022

Low-frequency non-astronomical changes of tides are among the most puzzling signals in the world ocean. Although the relevance of these signals in the order of a few cm is gradually being appreciated in the context of coastal flooding or de-aliasing of satellite gravimetry observations, a detailed quantitative understanding of the causative mechanisms has been lacking. Among the suspected forcing factors are fluctuations and trends in relative sea level, basin geometry (associated with, e.g., melting Antarctic ice-shelves), bed roughness, and ocean stratification. Here, we use a high-resolution general circulation model to spatially map the influence of stratification changes on the global M2 tide, on time scales from years out to decades. We conduct global tidal simulations in annually changing density structures, as drawn from hydrographic profiles and other external datasets (e.g., an eddying ocean reanalysis) from 1993 to present day. We perform internal-tide permitting simulations (1/12° horizontal grid spacing, 50 vertical layers) to resolve the relevant physics, particularly low-mode barotropic-to-baroclinic energy conversion at topographic features and vertical mixing in shallow water. Atmospheric forcing is omitted to constrain the model’s density distribution to the prescribed initial hydrography. We validate the resulting annual M2 amplitude changes against estimates from harmonically analyzed tide gauge series, distributed across the globe. Particular emphasis in our analysis is given to the tropical Pacific and the South China Sea, where the seesawing of stratification between positive and negative phases of ENSO (El Niño-Southern Oscillation) is expected to introduce spatially coherent amplitude modulations of ±1 cm on interannual time scales.
Drivers of forest resistance to bark beetle disturbance in European forests
Authors: Jaime Luciana , Batllori Enric , Ferretti Marco , Lloret Francisco
Published: March 2022

Bark beetle infestation is a major causal agent of tree mortality that may be critical for forest persistence under future climates with increased warming and drought episodes. Such persistence, in terms of resistance to bark beetle disturbance, could be determined by the location of host tree populations in the species’ climatic niche space, increasing close to the host climatic optimum and reducing close to the beetle climatic optimum. Therefore, we analyzed the resistance of European coniferous forests to bark beetle attack and its derived tree mortality, using successive censuses of forest damage surveys in relation to the climatic niche characterization of both host tree and bark beetle species. Specifically, we modelled the responses of forest resistance in relation to the distance to the niche optimum of the host tree and beetle species, stand attributes and previous drought characteristics. Regional patterns of recent beetle disturbance evidenced that forests in Central, North, and East of Europe could be at risk under the attack of multivoltine bark beetle species. In addition, we found that forest resistance to beetle attack was determined by several driving factors. The environmental position of the affected forest within the host and beetle species’ climatic niche and the stand attributes mediated the influence of drought on the resistance to beetle attack. In particular, monospecific stands with a high frequency of drought in previous years and located close to both host tree and beetle climatic optimum showed low resistance to beetle attack. In turn, forest resistance to derived tree mortality was exclusively determined by the intensity and duration of previous drought. Once the forest resistance is exceeded to be infested, the mortality of host tree populations may be enhanced with the severity of drought events. These findings revealed that the resistance of European coniferous forests to bark beetle disturbance is modulated by the joint host-insect climatic suitability and by beetle-drought interactions. Moreover, the expected increase of extreme drought events in the coming decades, particularly under the threat of multivoltine bark beetle species activity, may amplify beetle-induced tree mortality threatening forest persistence.
Structure of Motifs in Seismic Networks
Authors: Pană Gabriel , Băran Virgil , Nicolin Alexandru
Published: March 2022

We report detailed statistical results on the structure of motifs in seismic networks covering four distinct terrain regions. Our main finding is that all seismic networks under investigation display motifs which have a distinct scale-free-like structure. 

The seismic networks were constructed from public seismic data using a standard procedure which relies on splitting the seismic region into equally sized cubes, which are the nodes of the seismic network. Then, placing each earthquake, in chronological order, into the cube corresponding to its epicenter, we define a link between two nodes as a series of two subsequent earthquakes with epicenters in different cubes. Using these seismic networks we study the occurrence of 3-node and 4-node motifs, which are triangles and tetrahedrons of the network, and report a scale-free-like behavior of the area or volume of these motifs weighted by the total energy released by the earthquakes contained in the nodes of the motif.

The statistical properties of motifs, in particular the scaling exponents of the aforementioned scale-free-like distributions, can be used to assess the differences and similarities between different seismic regions, without taking into account the inner workings of the plate tectonics. Our approach is fully customizable as all relevant parameters of the network (e.g., size of the cubes, magnitude of earthquakes, considered timeframe, coordinates of epicenters) can be changed to accommodate virtually all seismic regions.  
Data treatment and systematic analysis of MC-ICP-MS 230Th/238U-dating of secondary carbonates
Authors: Kerber Inga Kristina , Kontor Fabian , Eichstädter René , Schröder-Ritzrau Andrea , Warken Sophie , Frank Norbert
Published: March 2022

Carbonate based archives, such as speleothems and cold-water corals, yield valuable information on past states of the climate system. The key chronometer to access the deposition times of these archives is 230Th/U dating, typically measured using multi-collector inductively coupled plasma mass spectrometers (MC-ICP-MS). Here, we present our Python-based data treatment, correction and age calculation algorithm equipped with a graphical user interface (GUI) which ensures reproducibility and allows for customized calculation constants. We outline the relevance of proper data outlier treatment and review hardware settings such as fade-out times of Faraday cups (FC).  Furthermore, we systematically analyse the effect of variation in different MC-ICP-MS raw data corrections as tailing and process blank on the accuracy of the atomic ratios 230Th/238U and 234U/238U and the ages. To do so, three speleothem samples of different isotopic concentrations and ages were employed. We find that already a variation in tailing of 10 % causes a deviation on the permille level from the actual age for older samples (~150 ka), whilst younger samples are hardly affected. Process blank (instrumental background) measurements in turn affect the youngest samples strongest, as we found that an unnoticed increase of 50 % of the process blank results in a deviation on the percent level for the youngest sample (few hundred years). On contrary, hydride correction is minor for all samples, thus all time scales. In conclusion, the methods presented here permit routine precision levels of isotope analysis in the order of 5 ε units (1 ε-unit = 10-4).
Application of frequency ratio modelling technique for predictive flooded area susceptibility mapping using remote sensing and GIS
Authors: Jariwala Khushboo , Agnihotri Prasit , Patel Dhruvesh , Pathan Azaz , Mohseni Usman , Patidar Nilesh
Published: March 2022

Coastal areas are directly vulnerable to natural disasters like floods, which causes massive damages to natural resources and human resources. Dam induces floods can be devastating for surrounding low lying areas. Bharuch is a district with substantial industrial growth, and intended human activities were causing an imbalance in natural resources for planning and fulfilling other demands. Floods can be devastating concerning the Bharuch district's social, economic, and environmental perspectives. The proper analysis becomes very important to reduce the impact and find mitigation measuring techniques. I did flood susceptibility mapping using the frequency ratio model for the six sub-districts of the area. The susceptibility of a flood was analysed using the frequency ratio model by considering nine different independent variables (land use/land cover, elevation, slope, topographic wetness index, surface runoff, lithology, distance from the main river, soil texture, river network) through weighted-based bivariate probability values. In total, 151 historical floods were reported. I took locations for this study, from which I used 72 locations for susceptibility mapping. I combined the independent variables and historic flood locations to prepare a frequency ratio database for flood susceptibility mapping. The developed frequency ratio was varied from 0 to 13.2 and reclassified into five flood vulnerability zones, namely, very low (less than 0.99), low (0.99-2.04), moderate (2.04-5.58), high (5.58-13.2) and very high susceptibility (more than 13.2). The flood susceptibility analysis will be a valuable and efficient tool for local government administrators, researchers, and planners to devise flood mitigation plans.

Keywords: Flood Susceptibility · Flood · Frequency Ratio · Vulnerability · Bharuch
Evolution state identification of deep landslide displacement based on a quadratic wavelet reconstruction and bispectrum analysis method
Authors: Long Jingjing , Li Changdong , Liu Yong , Feng Pengfei
Published: March 2022

Deformation monitoring has been proven to be an effective way to forecast and mitigate landslide geohazards. With the development of monitoring technology and equipment, the GPS technology have been widely adopted in landslide surface displacement monitoring, and borehole inclinometer methods are often used to measure deep displacements. However, for landslides with large and abrupt deformations, a large amount of landslide deep displacement data can hardly be processed by traditional methods because of the shearing failures of inclinometers, which cause serious data redundancy. Considering the time-frequency characteristics of deep displacement data obtained from typical rainfall-reservoir induced landslides in China Three Gorges Reservoir (CTGR) area, a quadratic wavelet reconstruction and bispectrum analysis (QWRBA) method is designed for feature extraction and landslide state classification. During this process, two wavelet decompositions are first used to decompose the input deep displacement data into components with different physical meanings. Then, some reconstructed components and non-reconstructed components are analysed with a bispectrum. The deep displacement bispectrum features generated by the bispectrum analysis of each component are fused to obtain the eigenvalues of these bispectrum features, and the eigenvalues of the fused bispectrum features are used as the characteristic landslide deep displacement data. By utilizing the fused bispectrum features as the inputs of an adaptive moment estimation-based convolutional neural network (CNN), different deep displacement conditions are recognized as corresponding deformation states. 
Long-term prediction of groundwater levels for climate scenarios with machine-learning tools
Authors: Gosses Moritz , Wöhling Thomas
Published: March 2022

Estimating the effects of climate change on water resources is an important topic for researchers in hydrological sciences. Climate model outputs can be used as inputs for calibrated numerical groundwater models to predict the effect of different climate scenarios on groundwater levels. Unfortunately, spatially explicit numerical models are spatially constrained, data-hungry, and difficult to set-up and to calibrate. Furthermore, the involved model run-times make proper uncertainty analysis of the model predictions computationally expensive.
Machine-learning (ML) tools have become recognized as a powerful alternative for numerical models for different applications in hydrological science, but come with their own challenges. They have been successfully used for the prediction of groundwater levels in single bores based on historical data, but their application for estimating groundwater levels for climate scenarios is still a matter of active research.
To identify the potential of ML techniques for this application, two different ML algorithms have been applied to predict groundwater levels for several climate scenarios at a number of groundwater wells with long-term historical data time series. The two ML algorithms are (i) multi-layer perceptrons (MLP) with a closed feedback loop and (ii) long short-term memory (LSTM) networks. For each observation well, several thousand versions of these ML models with differing setups are trained to historical, monthly data time series up to 2015 and then applied for the estimation of monthly groundwater levels. These estimations are computed by using climate model outputs for different scenarios, as well as artificially generated scenarios, as drivers for the ML models to test their sensitivity and plausibility to those input data series. The high quantity of model versions for each bore are utilized to generate mean groundwater level estimates and accompanying uncertainty bands via Bayesian Model Averaging (BMA).
Both ML techniques are able to match the historical data time series for the different bores with small uncertainty, but differ in their ability to predict long-term groundwater levels from climate change and artificial scenarios. The long-term simulations of the MLP models show believable trends and appropriate uncertainty bands, while the LSTM networks seem to underestimate the uncertainty of their future predictions.
The Ionospheric Alfvén Resonator observed at Eskdalemuir magnetic observatory  
Authors: Hodnett Rosie , Yeoman Timothy , Wright Darren , Beggan Ciarán
Published: March 2022

Ionospheric Alfvén Resonances (IAR) are observed in the British Geological Survey's ground based induction coil magnetometer data at Eskdalemuir. IAR are caused when Alfvén waves are partially reflected at boundaries of changing plasma density in the ionosphere. At the boundaries, the Alfvén velocity reaches a maximum and the IAR occurs in the cavity which is in the F region. In the data we observed some unusual variations in the frequency of the harmonics and so created a model to investigate this. We have modelled the harmonic frequency separation of the IAR using the magnetic field strength from the International Geomagnetic Reference Field, and the electron density and ion composition from the International Reference Ionosphere. We found the Alfvén velocity and calculated the time of flight for the Alfvén wave to travel up and down the cavity, and hence we found the frequency. The model shows that the frequency is highest in the winter, and often shows a double peak each day in the winter months. We then compared the model of the harmonic frequency separations to the harmonic frequency separations from the data, determined from an autocorrelation analysis of the observed spectra.
Influence of Atmospheric Teleconnections on Interannual Variability of Arctic-boreal Fires
Authors: Zhao Zhiyi , Lin Zhongda , Li Fang , Rogers Brendan M.
Published: March 2022

Fires across the Arctic-boreal zone (ABZ) play an important role in the boreal forest succession, permafrost thaw, and the regional and global carbon cycle and climate. These fires occur mainly in summer with large interannual variability. Previous studies primarily focused on the impacts of local surface climate and tropical El Niño-Southern Oscillation (ENSO). This study, for the first time, comprehensively investigates the influence of summer leading large-scale atmospheric teleconnection patterns in the Northern Hemisphere extra-tropics on interannual variability of ABZ fires. We use correlation and regression analysis of 1997–2019 multiple satellite-based products of burned area and observed/reanalyzed climate data. Results show that eight leading teleconnection patterns significantly affect 63±2% of burned areas across the ABZ. Western North America is affected by the East Pacific/North Pacific pattern (EP/NP) and the West Pacific pattern (WP); boreal Europe by the Scandinavia pattern (SCA); eastern North America, western and central Siberia, and southeastern Siberia by the North Atlantic Oscillation (NAO); and eastern Siberia /Russian Far East by the East Atlantic pattern (EA). NAO/EA induces lower-tropospheric drier northwesterly/northerly airflow passing through the east of boreal North America/Eurasia, which decreases surface relative humidity. Other teleconnections trigger a high-pressure anomaly, forcing downward motion that suppresses cloud formation and increases solar radiation reaching the ground to warm the surface air as well as brings drier air downward to reduce surface relative humidity. The drier and/or warmer surface air can decrease fuel wetness and thus increase burned area. Our study highlights the important role of the extra-tropical teleconnection patterns on ABZ fires, which is much stronger than ENSO that was thought to control interannual variability of global fires. It also establishes a theoretical foundation for ABZ fire prediction based on extra-tropical teleconnections, and has the potential to facilitate ABZ fire prediction and management.
Gender equity actions at the ERC: results of sustained measures 
Authors: Jesus-Rydin Claudia , Fariña-Busto Luis , Romanowicz Barbara
Published: March 2022

The European Research Council (ERC), Europe’s premiere funding agency for frontier research, views equality of opportunities as an essential priority and a vital mission to ensure credibility in the review process. The ERC monitors closely various demographic data yearly on every call and has taken actions to tackle imbalances and potential implicit and explicit biases.

This presentation is focused on gender data for the three main funding schemes: Starting Grant, Consolidator Grant and Advanced Grant. After more than 12 years of existence, and various specific actions to tackle societal imbalances, ERC data provides an insight on the impact of various actions.

In the first framework programme (FP7, 2007-2013), 25% of applicants were women. In the last years (Horizon 2020, 2014-2020), this percentage increased by 4%, with 29% of women applying for ERC grants. In the same periods of time, the share of women as grantees has also increased from 20% to 29%. In the last years, men and women enjoy equal success rates.

The ERC knows that work to ensure equality of opportunities is never-ending. This presentation analyses the institutional efforts critically and considers possible steps to consolidate the accomplished results.
Subsurface storage drives drought propagation and recovery across climates and catchment properties
Authors: Bruno Giulia , Avanzi Francesco , Gabellani Simone , Ferraris Luca , Cremonese Edoardo , Galvagno Marta , Massari Christian
Published: March 2022

Extensive knowledge of hydrological processes occurring during droughts is required for a sustainable water resources management, especially in a changing climate. Large-sample analyses are particularly informative in this sense, because they allow us to extend the understanding beyond specific catchments. Data from experimental catchments and observatories showed that water stored within the catchment can sustain evapotranspiration and discharge during dry periods and previous multi-catchments studies on droughts highlighted the storage control on hydrological drought characteristics, through the quantification of hydrological signatures and catchment properties. However, few studies have explicitly quantified across different climates and catchment types the contribution of subsurface storage changes (ΔS) in the annual water balance, in drought propagation (from the meteorological to the hydrological one), and in drought recovery. Here, we assembled a dataset blending ground-based precipitation and discharge data, and remote-sensed actual evapotranspiration data to study drought propagation and recovery in a water-balance and data-based perspective for 102 catchments across various climatic and morphological properties in Italy. This region experienced severe drought years over the study period (hydrological years 2010 - 2019), as detected by the Standardised Precipitation Index for an accumulation period of 12 months. This large-sample analysis revealed that (i) subsurface storage is a non-negligible term in the annual water balance, as ΔS mean annual value represents on average the 11% of precipitation across the catchments, (ii) its depletion sustains discharge during drought years (median annual ΔS anomaly equal to -97 mm for catchments attenuating the hydrological drought with respect to the meteorological one), and (iii) it recovers from precipitation deficits over shorter time scales than evapotranspiration, but similar as those of discharge. These findings emphasize the need of explicitly considering subsurface storage in drought analyses to properly inform policy makers and water managers, as it is a key driver in drought propagation and recovery across climates and catchment properties.
Long-term prediction of Sudden Stratospheric Warmings
Authors: Vokhmianin Mikhail , Asikainen Timo , Salminen Antti , Mursula Kalevi
Published: March 2022

Polar vortex is a system of strong westerly winds which forms each winter in the polar stratosphere. Sometimes, roughly every other winter, the polar vortex in the Northern Hemisphere experiences a dramatic breakdown after associated warming of the polar stratosphere. Such events are called Sudden Stratospheric Warmings (SSWs). SSWs are known to have a significant influence on ground winter weather by leaking cold and harsh air, e.g., to Northern Eurasia and to large parts of North America. It is commonly thought that SSWs are generated by enhanced planetary waves, which propagate from the troposphere to the stratosphere. The waves break in the stratosphere and deposit their momentum there, which decelerates the vortex and leads to its breakdown.

It has been known for a long that the easterly direction of equatorial stratospheric QBO (Quasi-Biennial Oscillation) winds favors a weakening and eventual breaking of the northern polar vortex (the so-called Holton-Tan mechanism). However, it was recently shown that the occurrence rate of SSWs also depends strongly on geomagnetic activity. Breaking of the polar vortex is very likely to occur if the geomagnetic activity is weak and QBO winds are easterly. Weak geomagnetic activity corresponds to a low level of solar wind-driven energetic particle precipitation into the polar stratosphere, while the easterly QBO phase guides the planetary waves preferentially into the polar vortex.

Here we examine the possibility of using these results to predict the occurrence probability of SSWs with a long lead time of several months. We formulate a model, where the SSW probability depends on geomagnetic activity represented by Aa index and on the QBO phase. We evaluate the optimal lead times for geomagnetic activity and the QBO phase, and the optimal altitude level where the QBO has the greatest influence on the SSW probability. We will also estimate the statistical confidence limits for the derived probability.
A sequence-stratigraphic framework for the Toarcian – Aalenian from southern Germany based on x-ray fluorescence core scanning data
Authors: Mann Thomas , Bornemann André , Erbacher Jochen
Published: March 2022

Lower and Middle Jurassic sedimentary deposits in southern Germany have accumulated in a shallow-marine shelf environment and are typically dominated by clayey lithologies with minor occurrences of sandstones and limestones. The sedimentary evolution and paleoclimatic significance of these poorly exposed deposits often remain largely unexplored. Here we present a suite of high-resolution x-ray fluorescence (XRF) core scanning data from southern Germany covering the Upper Toarcian and Aalenian stages. The overall objective of this study is to identify Transgressive-Regressive cycles based on the analysis of three cores obtained during scientific drilling campaigns in 2019-2021. Cores have been analyzed with an Avaatech XRF Core Scanner at a 10 mm sampling interval, an energy of 10 keV and a current of 500 µA to measure element intensities ranging from aluminium through iron. Resulting trends in elemental ratios indicative for subtle grain-size variations such as Si/Al are used to reconstruct shoreline trajectories and establish a sequence stratigraphic framework (see Thöle et al. 2020). Particularly the thick and largely homogenous Opalinuston Formation appears suitable in that respect, likely resulting from extraordinarily high sedimentation rates during the lower Aalenian in southern Germany, thus providing a complete but unexplored archive of paleoclimatic signals.

 

References:

Thöle, H., Bornemann, A., Heimhofer, U., Luppold, F. W., Blumenberg, M., Dohrmann, R., & Erbacher, J. (2020). Using high‐resolution XRF analyses as a sequence stratigraphic tool in a mudstone‐dominated succession (Early Cretaceous, Lower Saxony Basin, Northern Germany). The Depositional Record, 6(1), 236-258.
An enhanced deep learning approach to assessing inland water quality and the affecting factors using Landsat 8 and Sentinel-2
Authors: Guo Hongwei , Zhu Xiaotong , Huang Jinhui , Zhang Zijie , Tian Shang , Chen Yiheng
Published: March 2022

The estimation of water quality parameters (WQPs) using remote sensing is difficult due to the complex correlation between WQPs and water optical properties, the interactions of WQPs, and the impacts of climate. We proposed enhanced multimodal deep learning (EMDL) models for Chlorophyll-a (Chla), total phosphorous (TP), total nitrogen (TN), Secchi disk depth (SDD), dissolved organic carbon (DOC), and dissolved oxygen (DO) estimation in Lake Simcoe, Canada. The EMDL models were developed and validated using the remote sensing reflectance derived from the harmonized Landsat and Sentinel-2 images, synchronized in-situ water quality measurements, water surface temperature, and climate data (N = 950). Using the EMDL models, the spatiotemporal water quality patterns of Lake Simcoe from 2013 to 2019 were reconstructed. Besides, we quantitatively analyzed the impacts of 12 potential natural and anthropogenic factors on the water quality of Lake Simcoe. The results showed that the EMDL models had the potential to detect the spatiotemporal dynamics of water quality with the Slope being close to 1 (0.84−0.95), normalized mean absolute error ≤ 20.17%, and Bias ≤ 14.68%. Human activities such as urban development and agricultural activities mainly affected the water quality of Lake Simcoe. This study provides a practical approach to supporting the environmental management of regional inland watersheds.
Tungsten isotope implications for the source of ocean island basalts from the Marquesas Archipelago
Authors: Herret Marie-Theres , Mundl-Petermeier Andrea , Castillo Paterno , Kim Doyeon
Published: March 2022

The application of the short-lived radiogenic 182Hf/182W-system (t1/2 = 8.9 Ma [1]) is a good approach to study early differentiation processes or potential involvement of long-term isolated and/or core-influenced mantle domains as components for ocean island basalts (OIB) [2,3].

Several examples of OIB worldwide (e.g., Hawaii, Samoa and Iceland) exhibit a negative He-W correlation [2], possibly connected to the incorporation of primordial material characterized by high 3He/4He ratios and negative µ182W (182W/184W deviation of a sample from laboratory standards in parts per million). Anomalous W isotope compositions in combination with elevated 3He/4He ratios have previously been connected to seismically anomalous structures in the lowermost mantle, so-called “(mega) ultra-low velocity zones” [3]. Recently, such a structure was discovered beneath the Marquesas Archipelago [4]. This volcanic island chain is located in the South Pacific, in proximity of the Marquesas Fraction Zone. Its formation process is not yet fully understood. Based on high 3He/4He ratios in combination with other geochemical characteristics, such as Sr, Nd and Pb isotopes, a deep-lying mantle source has been suggested [5].

In this study, we have analysed seven samples from two islands of the Marquesas Archipelago, which exhibit 3He/4He ratios up to 14.4 Ra [5]. µ182W ranges from -3.6 ±3.1 to 4.7 ±8.5. Hence, despite elevated 3He/4He in some of the samples, none of them display resolved negative 182W anomalies and thus, no negative He-W correlation is observed. Interpretations for the decoupling of He-W systematics in samples from the Marquesas Archipelago will be discussed.

 

References:

[1] Vockenhuber et al., 2004, Phys. Rev. Lett.

[2] Mundl et al., 2017, Science

[3] Mundl-Petermeier et al., 2020, Geochim. Cosmochim. Acta

[4] Kim et al., 2020, Science

[5] Castillo et al., 2007, Chem. Geol.