bluuebunny/crossref_metadata_2025 huggingface dataset:
A geoarchaeological approach for reconstructing last glacial temperatures using coupled isotopic analyses of fossil snails and stalagmites from limestone caves in Okinawa, Japan
Authors: Asami Ryuji , Hondo Rikuto , Uemura Ryu , Fujita Masaki , Yamasaki Shinji , Shen Chuan-Chou , Wu Chung-Che , Jiang Xiuyang , Takayanagi Hideko , Shinjo Ryuichi , Kano Akihiro , Iryu Yasufumi
Published: March 2022

We applied a new geoarchaeological method with two carbonate archives, which are fossil snails from Sakitari Cave and stalagmites from Gyokusen Cave, on Okinawa Island, Japan, to reconstruct surface air temperature changes over the northwestern Pacific since the last glacial period. Oxygen isotope ratios of modern and fossil freshwater snail shells were determined to infer annual and seasonal temperature variations. The observational and analytical data confirm that oxygen isotopic values of fluid inclusion waters in the stalagmite can be regarded as those of spring waters at the sites where snails lived. Our results indicate that the annual mean, summer, and winter air temperatures were lower by 6–7 °C at ca. 23 thousand years ago (ka) and 4–5 °C at ca. 16–13 ka than those of the present day. Our reconstruction implies that surface air cooling was possibly two times greater than that of seawater around the Ryukyu Islands during the Last Glacial Maximum, which potentially enhanced the development of the East Asian summer monsoon during the last deglaciation. Considering the potential uncertainties in the temperature estimations, the climatic interpretations of this study are not necessarily definitive due to the limited number of samples. Nevertheless, our new geoarchaeological approach using coupled isotopic determinations of fossil snails and stalagmite fluid inclusion waters will be useful for reconstructing snapshots of seasonally resolved time series of air temperatures during the Quaternary.
Comprehensive Insights Into O3 Changes During the COVID-19 From O3 Formation Regime and Atmospheric Oxidation Capacity
Authors: Wang Peng , Zhu Shengqiang , Zhang Hongliang
Published: March 2022

Economic activities and the associated emissions have significantly declined during the 2019 novel coronavirus (COVID-19) pandemic, which has created a natural experiment to assess the impact of the emitted precursor control policy on ozone (O3) pollution. In this study, we utilized comprehensive satellite, ground-level observations, and source-oriented chemical transport modeling to investigate the O3 variations during the COVID-19 pandemic in China. Here, we found that the significant elevated O3 in the North China Plain (40%) and Yangtze River Delta (35%) were mainly attributed to the enhanced atmospheric oxidation capacity (AOC) in these regions, associated with the meteorology and emission reduction during lockdown. Besides, O3 formation regimes shifted from VOC-limited regimes to NOx-limited and transition regimes with the decline of NOx during lockdown. We suggest that future O3 control policies should comprehensively consider the effects of AOC on the O3 elevation and coordinated regulations of the O3 precursor emissions.
Evidence-based uncertainty estimates for the International Geomagnetic Reference Field
Authors: Beggan Ciaran
Published: March 2022

The International Geomagnetic Reference Field (IGRF) is a multi-institute model of the Earth’s magnetic field, compactly described by sets of up to 195 spherical harmonic (Gauss) coefficients to degree and order 13, which allows the continuous evaluation of the field at any location and time on or above the surface. It is developed from satellite and ground-based magnetometer data and describes the large-scale variation of the magnetic field in space and time under quiet conditions. While much effort has been made on improving the forecast of the secular variation of the field over the five-year intervals between release and renewal, less emphasis has been placed on understanding the spatial errors from a user point of view. We estimate the large-scale time-invariant spatial uncertainty of the IGRF based on the globally averaged misfit of the model to semi-independent ground-based measurements at repeat stations and observatories between 1980 and 2021. As the ground measurements are reduced to quiet-time values, the external field is minimized. We find the 68.3% confidence interval is 87 nT in the North (X) component, 73 nT in the East (Y) component and 114 nT in Vertical (Z) component. Due to the Laplacian distribution of the residuals, the standard deviations are larger at 144, 136 and 293 nT, respectively.
Fault reactivation process in the laboratory: The role of stress cycling and pressurization rate
Authors: Naderloo Milad , Veltmeijer Aukje , Barnhoorn Auke
Published: March 2022

Over the last few decades, it has become apparent that different human activities in the subsurface, such as water waste injection, hydraulic fracturing, and geothermal energy production can lead to induced seismicity. Understanding the effects of fluid injection-related parameters on seismic response or evolution of it is essential for finding a method to manage and minimize the induced seismicity risk. Experimental and numerical studies indicate that varying injection patterns and rates can be used to effect and/or mitigate seismicity. However, most of the studies are for intact rock medium, and the mechanism of injection-induced seismicity of faulted rock medium is not clear yet. In this study, we performed fault reactivation experiments on faulted (saw-cut) Red Pfaelzer sandstones to provide new insight into the effect of stress/pressure cycling and rate on fault slip behavior and seismicity evolution. The saw-cut samples were subjected to two different reactivation mechanisms: 1) stress-driven and 2) injection-driven fault reactivation. Three different reactivation scenarios were performed during the stress-driven fault reactivation experiments: continuous sliding, cyclic sliding, and under-threshold cycling sliding. Ten AE transducers were used to detect microseismicity during the fault reactivation experiments, and consequently, different microseismic parameters, such as frequency-magnitude distribution (b-value), AE energy, and AE rate were estimated. Stress-driven fault reactivation experiments showed that (i) a below-threshold cycling scenario prevents seismicity and pure shear slip; however if the shear stress exceeds the previous maximum shear stress, seismicity risk increases drastically in terms of b-value, maximum AE energy, and magnitude. (ii) Compared to continuous sliding, cyclic sliding triggers less seismicity in terms of total b-value and large AE events due to the uniform reduction in roughness and asperity on the fault plane. (iii) By increasing the number of cycles, in general, the number of generated events and AE energy per cycle is reduced. Nevertheless, there is a risk of generating large AE events during the first cycles. In addition, results from the injection-driven fault reactivation experiments demonstrated that high injection rate results in higher peak slip velocity. Compared to the stepwise injection pattern, the cyclic recursive injection scenario showed higher peak slip velocity, due to the high hydraulic energy budget and fault compaction. A proper injection strategy needs to consider various factors, such as fault drainage, critical shear stress, injection rate, and injection pattern (frequency and amplitude). Our results demonstrate that selecting proper stress/pressure amplitude, and pressurization rate for the injection design strategy can help to reduce seismicity risk.  
Hansbreen’s calving-driven ice loss derived from seismic data supported by millimetre-wave radar scans and neural networks
Authors: Gajek Wojciech , Harcourt William , Pearce Dannielle
Published: March 2022

Calving of tidewater glaciers is a key driver of glacier mass loss as well as a significant contribution towards sea level rise. However, this dynamic process is still challenging to quantify. In addition, there are very few direct measurements of calving activity in Svalbard at daily to sub-daily resolution due to the requirement of continuous human labour at the calving front for field studies. Seismic instruments in the vicinity of glaciers offer the potential to circumvent this issue since they record ground motion signals, including those generated by calving events, with an unprecedented sub-second resolution. Such data sets are not affected by site conditions like poor visibility or darkness and, in the case of permanent regional seismological stations, already offer long-term datasets. Despite this, a knowledge gap remains which prevents making a direct link between precise calving volumes and seismic records. This study presents our effort made towards obtaining an estimate of volumetric ice loss from integrating seismic records with 3D millimetre-wave radar measurements of a tidewater glacier calving front. In the summer of 2021, an 8-day long time series of integrated measurements was acquired at the calving front of Hansbreen, South Spitsbergen. It included remote sensing observations from a millimetre-wave radar (AVTIS2), Terrestrial Laser Scanner and time-lapse cameras correlated with a seismic dataset from two local arrays deployed at direct vicinity of calving front and a closeby regional permanent seismological station in Hornsund. Integrating these datasets brings an opportunity to correlate visual observations of calving including volumetric ice loss derived from radar scans with seismic signatures registered at nearby seismic arrays. We explore various parameters that characterize observed calving events and develop a model linking chosen parameters with ice loss using machine learning techniques. Local arrays were installed for a limited time and the calibrated parameters are expected to change spatially. Therefore, we further transfer our approach and integrate decade long records from nearby permanent seismological station. Limiting data to a single station record reduces both the accuracy of estimated ice volume and spatial resolution. However, it enables us to apply detection algorithm trained using observed calvings to decade long records and, consequently, to revisit a decade long history of Hansbreen's calving.
Combining hydrology, carbon and nutrient cycles for better peatland management 
Authors: Laurén Annamari (Ari) , Könönen Mari , Kiuru Petri , Launiainen Samuli , Hökkä Hannu , Urzainki Iñaki , Palviainen Marjo
Published: March 2022

Economic, climate and water protection targets need to be balanced in acceptable peatland management. This is not a simple task as the targets are not necessarily synergetic, and  hydrology, carbon (C) and nutrient cycles are tightly connected forming a complex network of feedbacks and interactions. Thus, planning of peatland management calls for holistic simulation models. Recently, we have developed Peatland simulator SUSI (Lauren et al. 2021) as a platform for a combined modelling of hydrology, biogeochemistry, and tree stand growth under different water table (WT) management (drainage) regimes. SUSI simulates WT, organic matter decomposition, nutrient release and tree growth between two parallel ditch drains in daily time step, and allows us to change meteorological input data, stand and peat characteristics, ditch depth and the distance between the ditches. Here, we extended SUSI to account for forest thinning and ash fertilization as management practises. To allow simulation of logging residue decomposition, we substituted the earlier empirical decomposition model with a simple compartmental process model describing separately the decomposition of tree stand litter and peat. Effect of ash fertilization was modelled so that the leaf biomass was adjusted according to the prevailing nutrient supply and the stand nutrient demand. Improving nutrient supply allows a higher leaf mass and elevated light and water use efficiency. The new modifications allow unraveling the feedback loop extending from improved nutrient availability → increased leaf mass, light and water use efficiency → lowering WT →  increased nutrient release from peat → improved stand growth → increased litterfall → changed C and nutrient balance → further lowering WT. The new model also includes lateral C fluxes. Release of dissolved organic carbon (DOC) in labile and recalcitrant form was calculated using computed WT, soil temperature, peat bulk density, and literature-derived release rates. The DOC release and the biodegradation of DOC to CO2 were connected as a source term to a 2-dimensional advection equation describing water movement and the equation was solved using a finite volume method. The model conceptualization, structure and the significance of the feedback mechanisms are analyzed and discussed. The new model enables, for the first time, internally coherent balancing among the economic, climate and water protection targets in management of boreal and tropical peatlands.
Rainfall threshold curves and machine learning approaches for pluvial flood forecasting based on local news reports in Croatia
Authors: Krvavica Nino , Horvat Bojana , Marinović Ivana , Šiljeg Ante
Published: March 2022

This study presents a forecasting model for pluvial flooding in the city of Zadar, Croatia, where a huge mesoscale convective system recently caused massive pluvial flooding and widespread property damage. Flood forecasting approaches based on hydrologic-hydraulic models require a large set of accurate data to provide reliable simulations. They also require many simulations, which can be computationally expensive and time consuming. Therefore, we are investigating the possibility of using a data-driven approach based on local news reports of pluvial flooding combined with a local high-resolution rain gauge. To this end, we considered two different computational approaches. The first - a conventional one - is based on rainfall threshold curves that define the critical rainfall depth for different time periods above which flooding is likely to occur. The second approach is based on machine learning and a classification problem - predicting whether accumulated rainfall depths over different time periods will lead to pluvial flooding. For the second approach, we considered 10 different methods that belong to five categories of machine learning typically used for classification problems. They are logistic regression, support vector machine, discriminant analysis, decision trees, and nearest neighbours. After a careful analysis, we defined rainfall threshold curves for Zadar that can be used for an early warning system and flood forecasting. We show that some machine learning models can provide slightly more accurate predictions than the threshold curve, with quadratic discriminant analysis being the most successful method for this purpose. Overall, this study shows that flood forecasting based on news reports in the city of Zadar can be a reliable approach. The analysis conducted in this study has laid the foundation for the implementation of an early warning system and pluvial flood forecasting in the Croatian coastal area.
Cosmic Ray Flux Correlation between McMurdo and Jang Bogo Neutron Monitor Stations vs. Time Lag
Authors: Kittiya Ekawit , Nuntiyakul Waraporn , Seripienlert Achara , Evenson Paul , Saiz Alejandro , Ruffolo David , Oh Sueyon
Published: March 2022

A neutron monitor is a large ground-based detector responding to the flux of cosmic ray particles in space by measuring atmospheric secondary neutrons. Any ground-based detector is sensitive to cosmic rays from a specific range of directions in space. In particular, a particle arriving from a specific sky direction with a specific rigidity (momentum per unit charge) was necessarily moving from a certain direction in space, called the asymptotic direction. McMurdo and Jang Bogo neutron monitor stations are Antarctic stations with similar geomagnetic latitudes but slightly different longitudes. From December 17, 2015 to January 9, 2017, six of the eighteen neutron counters from McMurdo had been transferred to Jang Bogo (with full transfer to Jang Bogo completed in December 2017). We present an analysis of the correlation of the cosmic ray flux between the McMurdo and Jang Bogo stations, during the time when both were operating, with ten-second time resolution. Although highly correlated, there are significant differences, including a systematic time lag of approximately 16 minutes between the data from the two stations. Although McMurdo observes with similar asymptotic directions to Jang Bogo, the response-weighted average directions still have a substantial difference of 21.9 degrees in geographic longitude, so with Earth’s rotation, time-independent anisotropy effects should induce a lag of 88 minutes.  Because the observed lag of 16 minutes is intermediate between 0 and 88 minutes, the joint observations reveal structure in the interplanetary cosmic-ray density that is consistent with a combination of simultaneous temporal variations and non-simultaneous variations with direction (i.e., anisotropy). The research is supported in part by a TA/RA scholarship (active recruitment) of Chiang Mai University and Thailand Science Research and Innovation via Research Team Promotion Grant RTA6280002.
Deriving the Østrem curve to quantify supraglacial debris-related melt-altering effects on the Djankuat Glacier, Caucasus, Russian Federation
Authors: Verhaegen Yoni , Rybak Oleg , Popovnin Victor , Huybrechts Philippe
Published: March 2022

We have derived the glacier-specific Østrem curve to quantify the influence of a supraglacial debris cover on the mass and surface energy balance components of the Djankuat Glacier, a northwest-facing and partly debris-covered temperate valley glacier in the Caucasus region, which has been selected as a ‘reference glacier’ by the WGMS. A 2D energy balance model, in combination with meteorological data from automatic weather stations and ERA5-Land reanalysis data, are used to assess the melt-altering effect of supraglacial debris on the overall glacier runoff during 1 complete balance year. The main results show that both the surface energy balance and mass balance fluxes are modified significantly due to the presence of debris on the glacier surface. For very thin debris, a slight relative melt-enhancement occurs due to a decreased surface albedo. If debris, however, further thickens, the insulating effect becomes dominant and reduces the melt and runoff of the underlying ice significantly, as thermal conduction becomes the dominant process to induce ice melt beneath such thick debris layers. The above-mentioned effects are modelled to be increasingly pronounced with an increasing thickness of the superimposed supraglacial debris cover, and can be of great importance with respect to future glacio-hydrologic regimes and glacio-geomorphological processes.
Comparing drought indicators and negative impacts for the 2018–19 Central European drought event
Authors: Shyrokaya Anastasiya , Di Baldassarre Giuliano , Messori Gabriele , Pechlivanidis Ilias , Pappenberger Florian , Cloke Hannah
Published: March 2022

Despite the scientific progress in drought forecasting, it remains challenging to accurately predict the corresponding impact of a drought event. This is due to the unexplored relationships between (multiple) drought indicators and the impacts across spatiotemporal scales. In this study, we unravel these relationships by analysing the impacts of the severe 2018-2019 drought event in Central Europe. We calculated the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evaporation Index (SPEI) over various accumulation periods, and related the indicators to losses from the European Drought Impact Report Inventory (EDII)1 with a focus on agriculture and water supply. An initial assessment was performed by correlating monthly time series of the drought indicators and the impact data at the EU NUTS1 region level. We further used a Random Forest Model to measure the predictive power of the drought indicators for those impacts.

Our findings reveal significant relationships between the drought indicators and the impacts over different accumulation periods. The analysis also detects region-specific and time-variant differences during the 2018–2019 Central European drought event. As such, our work provides a new framework to unravel the drought indicators-impacts dependencies. In addition, it emphasizes the need to leverage available impact data to increase the capacity to forecast the drought impacts.

1 Last retrieved January 2022
Temperature dissipation in convective clouds during EUREC4A
Authors: Grosz Robert , Król Stanisław , Nowak Jakub , Malinowski Szymon
Published: March 2022

During the EUREC4A campaign high (up to 3 mm) resolution temperature time series have been collected with the UFT-2 (Ultra-Fast-Thermometer) onboard the BAS Twin Otter aircraft in the subtropical low atmosphere in and between trade wind warm cumulus clouds. The measurements covered a wide range of atmospheric conditions, from cloud interiors, through cloud shells, air spaces between the clouds, as well as the atmospheric boundary layer. Data, resolving scales down the dissipation range allow to estimate temperature dissipation rate (TD) directly from the recorded signal. Examples of temperature fluctuations and associate TD records, characteristic to the various atmospheric conditions, will be presented and discussed.
Evaluating and Interpreting Post-fire Water Quality Changes in Portuguese Reservoirs 
Authors: Nitzsche Niels , Nunes João Pedro , Parente Joana
Published: March 2022

Wildfires can have adverse impacts on adjacent aquatic ecosystems, the hydrological cycle and ultimately water management. Recent global events have cemented the need to study these impacts in fire-prone Regions. Surface waters experience contamination by ash loads and fire-induced erosion, where contaminants, both organic and inorganic are introduced into surface water bodies after precipitation events. These contaminants can be detected directly or indirectly through monitoring basic water quality parameters as proxies. 

This study is exploring the impacts of wildfires on the water quality of Portuguese water reservoirs, by analyzing and interpreting changes in water quality that occurred over the past 30 years (1990-2020). Yearly burned areas were calculated for the watersheds of selected reservoirs to identify major fire events. Time series of water quality parameters (BOD, COD, DO, NO3, TP, Conductivity, TSS and pH) from around 75 different reservoirs in Portugal were then explored via changepoint analysis to detect post-fire responses in each watershed. Further, possible causes or drivers for water quality impacts, such as the burned area, land-use, aridity, watershed size to reservoir volume ratio and fire severity will be explored and weighed through logistic regression techniques.  

The burned area of the examined watersheds ranged from <1% per year to around 85% per year. Preliminary results suggest high thresholds in fire size to detect clear impacts in the measured parameters. With fire season becoming more extreme in Mediterranean regions, larger impacts on reservoirs can be expected in the future.  

Acknowledgement: This work was produced in the framework of project FRISCO - managing Fire-induced RISks of water quality Contamination (PCIF/MPG/0044/2018), and funding attributed to the CE3C research center (UIDB/00329/2020). 
Research on the interaction between roots and soil of adaptable plants pyracantha in the karst region 
Authors: Guo Huan
Published: March 2022

Abstract: To explore the adaptable plants soil reinforcement effects in the karst region of southwest China. A horizontal pull friction test was performed on the roots and soil by using a three-year-old shrub Pyracantha, and the friction characteristics of root-soil interface were analyzed by scanning electron microscopy and interference method. The results indicated that :(1) the root system of pyracantha showed two failure modes in the pull-out test: the pull-out friction of root-soil interface increases with the increase of root diameter and vertical load. (2) When gravel content is set at 0, 10%, 30% and 50%, the frictional force between root and soil tends to decrease. (3) There was a positive correlation between root surface roughness and root diameter in diameter range of 1-6mm, with correlation coefficient R =0.995. (4) There is an obvious correlation between root-soil friction and roughness. These results are significant to further explore the mechanical mechanism of plant root-soil interaction, and to strengthen the shallow soil and repair the fragile ecological environment.

Key words: Karst; Pyracantha; Root-soil friction; Roughness
Interplay of global climatic and regional tectonic controls in marginal basins, with an example of the Cergowa Beds deposition (Outer Carpathians) during the Oligocene icehouse
Authors: Pszonka Joanna , Wendorff Marek
Published: March 2022

The culmination of climate cooling at the Eocene-Oligocene boundary, known as the Terminal Eocene Event (TEE), forced the eustatic sea level fall crucial for isolation of the Paratethys from the Tethys Ocean. The isolated, northern marginal region contained starved Carpathian Flysch basins characterised by reduced circulation, dysaerobic bottom conditions and increased influx of riverine freshwater. The Cergowa Beds (Lower Oligocene) serve as an example of the icehouse period-related deposition of sandstones and subordinate sandstones-mudstones emplaced by sediment gravity flows in a predominantly anoxic depository dominated by dark shales and associated fine-grained facies of the Menilite Beds. Autochthonous calcareous nannoplankton species indicative of brackish water conditions reflect the Cergowa basin isolation and strong influence by freshwater influx during the zone NP23. This stage was dominated by high volume, high-density sediment gravity flows, occasionally triggered by hyperpycnal effluents. Coalified terrestrial organic matter, especially abundant in the proximal sector and including tree trunk fragments up to 2 m in length, suggests direct connection existed between the fluvial supply and redeposition by sediment gravity flows, probably via a shelf-edge delta supplying the Cergowa basin. The marginal character of the Cergowa basin enables to detect even subtle episodes as: (i) the CCD fluctuations, reflecting coccolithophorid-rich productivity, which is recorded as the laminated pelagic Tylawa Limestones, or (ii) local slope disequilibria reflected by hybrid flows interpreted as resulting from synsedimentary tectonic deformations of the basin floor. Generally, the Alpine orogenic movements enhanced the basin isolation and shoaling by tectonic uplift of the source area. However, the late stage of the Cergowa basin development, dated by the nannoplankton zone NP24, represents an open sea realm supplied by turbidity currents of decreasing density, with time suppressed and finally replaced by the anoxic sediments of the Menilite Beds type. Therefore, the deepening of the marine environment progressed against the prevailing global cooling and continuing eustatic sea-level fall. This apparent discrepancy emphasises the importance of the regional tectonic deformations of the basin that superseded the global climatic influence.
Influence of chemical aging processes on releasing organic products from microplastics
Authors: Worek Jagoda , Styszko Katarzyna , Białas Anna
Published: March 2022

At the end of the 1940s, the production of plastics began on a large scale. Since then, a dynamic increase in their production has been observed. It is associated with a variety of applications and low costs. The negative consequences of the use of polymers and poor disposal are still growing. Microplastic is an important hazard. These are pieces of plastic, the size of which does not exceed 5 mm. Microplastic particles have already been detected all over the world. Increasingly, attention is being paid to their accumulation in the environment. During their stay in ecosystems, they undergo aging processes. Their structure and composition are changing. The washed substances are released into the environment. The aim of the research was to check the effect of artificial aging methods on the leaching of functional groups and changes in the structure of selected polymers. Polystyrene and polyethylene terephthalate were selected for the research. They belong to the most common kind of plastics. For aging, combined methods were used, with irradiation with UV lamp irradiation and hydrogen peroxide. Before and post-aging polymers were analyzed using spectroscopic methods and a microscope. ATR FTIR, Raman confocal microscope and FTIR microscope were used for this purpose. The tests showed leaching of organic products from the samples and the formation of additional  bands. The structure of plastics has changed. These changes show a possible degradation path for plastics with a significant environmental impact.
Discerning TGF and leader current pulse in ASIM observation
Authors: Mezentsev Andrey , Østgaard Nikolai , Marisaldi Martino , Neubert Torsten , Chanrion Olivier , Reglero Victor
Published: March 2022

TGFs are short-duration bursts of high-energy photons shot from Earth’s atmosphere to space. They are produced during the initial upward propagation of +IC lightning leaders and are often associated with LF radio sferics. The Atmosphere-Space Interactions Monitor (ASIM) instrument provides X- and gamma-ray measurements synchronous with optical recordings in 180-240 nm, 337 nm and 777.4 nm wavelengths, allowing simultaneous detection of TGFs and the lightning processes associated with them.

ASIM observations show that TGFs are accompanied by a prominent optical pulse that marks the beginning of a lightning flash. TGFs tend to precede the pulse slightly, but the short duration of TGFs, together with the delay of the optical pulses from photon scattering in cloud particles, does not allow to resolve the correct sequence of events with confidence.

The same problem is present in measurements of radio waves, where the waves emitted by the TGF currents usually are mixed with those of the lightning currents because of the temporal proximity of the processes.

Here we report a remarkable TGF, with a high fluence of 360 counts in the energy range 0.4 - 20 MeV and a relatively long duration of 580 µs. The associated optical pulse is clearly following the TGF, which leads us to conclude that the current surge inside the leader channel is not generating the TGF, as has been proposed by models, but instead that the TGF process conditions the current surge that follows.
Implications for the pre-Alpine evolution of the Eastern Alps – a U/Pb zircon study on the Austroalpine Schladming Nappe
Authors: Haas Isabella , Kurz Walter , Gallhofer Daniela , Hauzenberger Christoph
Published: March 2022

The Schladming Nappe, as a part of the Silvretta-Seckau Nappe System of the Eastern Alps, comprises pre-Alpine remnants of crystalline basement rocks which give important information for reconstructing the Variscan and even pre-Variscan history of the Alps.

The Schladming Nappe mainly consists of paragneisses being intruded by subsequently overprinted granitoids. U-Pb zircon ages were acquired through LA-MC-ICPMS to determine the magmatic emplacement of the metagranitoids and constrain the tectono-metamorphic history of the Schladming Nappe.

Within these meta-granitoids, several intrusive events can be distinguished: (1) a Cambrian event with 206Pb/238U zircon mean ages between 496±6.5 and 501±7 Ma, (2) a Late Devonian/Early Carboniferous event with zircon mean ages between 350±5 Ma and 371±5 Ma and (3) a Permian event with zircon mean ages between 261±3 Ma and 263±3.5 Ma. The youngest age group is only found in metagranitoids from the southeastern part of the Schladming Nappe. The tectonic contact to the metapelites of the Wölz Nappe system and therefore the affiliation of these Permian granitoids to the Schladming Nappe, however, is still enigmatic.

The various age groups can also be differentiated by their whole rock geochemistry. While all of the metagranitoids are peraluminous, the Cambrian age group exhibits higher SiO2 values compared to the Late Devonian age group. The Late Devonian age group shows higher contents of CaO, MgO, FeO, Al2O3, as well Sr and Ba and can be further divided into two subgroups, with one depicting a distinct negative Eu-anomaly (EuN/Eu*=0.44-0.69) and the other subgroup lacking one (EuN/Eu*=0.82-1.08). The Permian age group often displays high contents of K2O, Nb and Y.

The Late Cambrian to Early Ordovician metagranitoids can be classified as part of a magmatic arc system, probably belonging to the northern Gondwana margin. The early Variscan granitoids can also be interpreted as part of an active margin. The Permian granitoids show a within plate granite affiliation and can further be interpreted as A-type granitoids, probably related to post-Variscan lithospheric extension.
Landslide Susceptibility Modeling of an Escarpment in Southern Brazil using Artificial Neural Networks as a Baseline for Modeling Triggering Rainfall
Authors: Vieira Lucchese Luísa , Garcia de Oliveira Guilherme , Brenning Alexander , Correa Pedrollo Olavo
Published: March 2022

Landslide Susceptibility Mapping (LSM) and rainfall thresholds are well-documented tools used to model the occurrence of rainfall-induced landslides. In the case of locations where only rainfall can be considered a main landslide trigger, both methodologies apply essentially to the same locations, and a model that encompasses both would be an important step towards a better understanding and prediction of landslide-triggering rainfall events. In this research, we employ spatially cross-validated, hyperparameter tuned Artificial Neural Networks (ANNs) to predict the susceptibility to landslides of an area in southern Brazil. In a next step, we plan to add the triggering rainfall to this Artificial Intelligence model, which will concurrently model the susceptibility and the triggering rainfall event for a given area. The ANN is of type Multi-Layer Perceptron with three layers. The number of neurons in the hidden layer was tuned separately for each cross-validation fold, using a method described in previous work. The study area is the escarpment in the limits of the municipalities of Presidente Getúlio, Rio do Sul, and Ibirama, in southern Brazil. For this area, 82 landslides scars related to the event of December 17th, 2020, were mapped. The metrics for each fold are presented and the final susceptibility map for the area is shown and analyzed. The evaluation metrics attained are satisfactory and the resulting susceptibility map highlights the escarpment areas as most susceptible to landslides. The ANN-based susceptibility mapping in the area is considered successful and seen as a baseline for identifying rainfall thresholds in susceptible areas, which will be accomplished with a combined susceptibility and rainfall model in our future work.
Predicting seasonal landslide activity with Bayesian inference
Authors: Luna Lisa , Korup Oliver
Published: March 2022

Improving landslide prediction in time is key to reducing damage and fatalities in areas susceptible to landsliding. While most landslide early warning research has focused on establishing hydro-meteorological landslide thresholds on hourly to daily timescales, few studies globally have attempted to model or predict landslide seasonality. We use probabilistic models based on two intuitive metrics — counts of landslides and presence or absence of landslides — to predict landslide activity at monthly resolution. Our focus area is the Pacific Northwest region of the United States, which has one of the highest densities of landsliding in the country, and where seasonal landslide activity has been recognized but hardly quantified. We use Bayesian inference to combine data from five landslide inventories from the region with varying spatial and temporal coverage, data density, and reporting protocols to learn the regional pattern of seasonal landslide activity. Results of logistic and negative binomial regression show that the landslide season in the Pacific Northwest begins in November and is marked by credible increases in the probability of landsliding, average landslide intensity, and inter-annual variability. Landslide activity is highest between November and February, decreases from March through May, and stays low between June and October. Inter-annual variability in landslide activity is higher in winter than in summer months. These flexible models could be easily adapted to learn diverse seasonal patterns from other regions of the world, such as the East Asian Summer Monsoon peak observed in Japan or the Atlantic hurricane season fall peak seen in the Caribbean. Our results also show that Bayesian multi-level models are a promising way to combine data from multiple, seemingly incompatible landslide inventories from a single region with potentially wide-ranging future applications.
EPOS Data portal for cross-disciplinary data access in the Solid Earth Domain
Authors: Bailo Daniele , Michalek Jan , Jeffery Keith G , Atakan Kuvvet , Paciello Rossana ,   EPOS IT Team
Published: March 2022

The European Plate Observing System (EPOS) addresses the problem of homogeneous access to heterogeneous digital assets in geoscience of the European tectonic plate. Such access opens new research opportunities. Previous attempts have been limited in scope and required much human intervention. EPOS adopts an advanced Information and Communication Technologies (ICT) architecture driven by a catalogue of rich metadata. The architecture of the EPOS system together with challenges and solutions adopted are presented. The EPOS Data Portal is introducing a new way for cross-disciplinary research. The multidisciplinary research is raising new requirements both to students and teachers. The EPOS portal can be used either to explore the available datasets or to facilitate the research itself. It can be very instructive in teaching as well by demonstrating scientific use cases. 

EPOS ERIC had been established in 2018 as European Research Infrastructure Consortium for building a pan-European infrastructure and accessing solid Earth science data. The sustainability phase of the EPOS (EPOS-SP – EU Horison2020 – InfraDev Programme – Project no. 871121; 2020-2022) is focusing on finding solutions for the long-term sustainability of EPOS developments. The ambitious plan of geoscientific data integration started already in 2002 with a Conception Phase and continued by an EPOS-PP (Preparatory Phase, 2010-2014) where about 20 partners joined the project. The finished EPOS-IP project (EPOS-IP – EU Horison2020 – InfraDev Programme – Project no. 676564; 2015-2019) included 47 partners plus 6 associate partners from 25 countries from all over Europe and several international organizations.

The EPOS Data Portal provides access to data and data products from ten different geoscientific areas: Seismology, Near Fault Observatories, GNSS Data and Products, Volcano Observations, Satellite Data, Geomagnetic Observations, Anthropogenic Hazards, Geological Information and Modelling, Multi-scale laboratories and Tsunami Research. The Data portal Graphic User Interface (GUI) provides search functionalities to enable users to filter data by using several criteria (e.g. spatio-temporal extents, keywords, data/service providers, free-text); also, it enables users to pre-visualize data in Map, Tabular or Graph formats; the GUI finally provides details about the selected data (e.g., name, description, license, DOI), as well as to further refine the search in order to dig into a smaller level of granularity of data.

The presentation is showing achievements of the EPOS community with focus on the EPOS Data Portal which is providing information about available datasets from TCS and access to them. We are demonstrating not only features of the graphical user interface but also the underlying architecture of the whole system.
Environmental suitability of MSWI fly ash geopolymers: evaluation by leaching tests 
Authors: Caviglia Caterina , Destefanis Enrico , Bernasconi Davide , Pastero Linda , Pavese Alessandro , Viani Alberto , Mácová Petra , Zárybnická Lucie
Published: March 2022

This work is focused on the possible reutilization of municipal solid waste incinerator (MSWI) fly ash as a metakaolin replacement in the acid-based geopolymer. This type of geopolymer, obtained by the reaction between an aluminosilicate source (metakaolin) and phosphoric acid to form an Al-O-P/Si-O-P matrix (Wang et al, 2019), have displayed better performance than the traditional alkali-silicate geopolymer, in terms of corrosion resistance (Wagh et al, 2011), thermal stability and mechanical strength (Celerier et al, 2019). The replacement of up to 30 % wt has proved to not significantly alter the remarkable performance of the material, obtaining compressive strength values higher than 30 MPa. However, since fly ash contains dangerous substances as chlorides, sulfates, and heavy metals, which must be stabilized, it is important to evaluate the leching stability of the final materials.

Therefore, test cube blocks of 1x1x1 cm size, containing 10, 20 and 30 % wt of previously washed fly ash replacement with respect to metakaolin are prepared, with Al/P molar ratio of 1, liquid-to-solid ratio raging from 0.95-1 and 3 days at 60°C as curing temperature. 

Leaching tests, according to the European standards EN-12457 (2002), using deionized water at a ratio liquid to solid of 10, are applied to geopolymers blocks to evaluate the concentration of salts and heavy metals that usually exceeds the law threshold in the raw fly ash. Leachates are analyzed by ionic chromatography and ICP-MS: the results show that the concentrations of chlorides are under the legislation limits provided for not dangerous waste, as well as sulfates and fluorides; relatively to heavy metals Zn, Pb, Cd exceed the concentrations limits. Further tests and analyses are carried out to evaluate the impact of synthesis parameters on the leaching stability of these materials.

 

Reference

 

Wang, Y. Alrefaei, J. Dai. Silico-Aluminophosphate and Alkali-Aluminosilicate Geopolymers: A Comparative Review, Frontiers in Materials, 6 (2019), 106.

 

A.S. Wagh. Phosphate geopolymers, Ceramic Engineering and Science Proceeding, 32, 10 (2011), 91-103.

 

Celerier, J. Jouin, A. Gharzouni, V. Mathivet, I. Sobrados, N. Tessier-Doyen, S. Rossignol. Relation between working properties and structural properties from 27Al, 29Si and 31P NMR and XRD of acid-based geopolymers from 25 to 1000 °C, Materials Chemistry and Physics, 228 (2019), 293-302.
Northern Hemispheric extratropical cyclones during glacial times: impact of orbital forcing and ice sheet height
Authors: Raible Christoph C. , Messmer Martina , Jonathan Buzan , Emmanuele Russo
Published: March 2022

Extratropical cyclones are a major source of natural hazards in the mid latitudes as wind and precipitation extremes are associated to this weather phenomenon. Still the response of extratropical cyclones and their characteristics to strong external forcing changes is not yet fully understood. In particular, the impact of the orbital forcing as well as variations of the major ice sheets during glacial times on extratropical cyclones have not been investigated so far.  

Thus, the aim of this study is to fill this gap and to assess the impact of orbital forcing and northern hemispheric ice sheet height variations on extratropical cyclones and their characteristics during winter and summer. The main research tool is the Community Earth System Model CESM1.2. We performed a set of time slice sensitivity simulations under preindustrial (PI) conditions and for the following different glacial periods: Last Glacial Maximum (LGM), Marine Isotopic stage 4 (MIS4), MIS6, and MIS8. Additionally, we vary the northern hemispheric ice sheet height for all the different glacial periods by 33%, 66%, 100% and 125% of the ice sheet reconstructed for the LGM. For each of the simulations the extratropical cyclones are identified with a Lagrangian cyclone detection and tracking algorithm, which delivers a set of different cyclone characteristics, such as, cyclone frequency maps, cyclone area, central pressure, cyclone depth, precipitation associated to the extratropical cyclones as well as extremes in cyclone depth and extratropical cyclone-related precipitation. These cyclone characteristics are investigated for the winter and the summer season separately.

Preliminary results show that the extratropical cyclone tracks are shifted southwards on the Northern Hemisphere during the winter season. This shift has rather strong implication for the Mediterranean, with an increase of winter precipitation during glacial times over the western Mediterranean. The increase is modulated when changing the ice sheet height as extratropical cyclone tracks shift further south with increasing northern hemispheric ice sheet height. The orbital forcing shows a higher impact during summer, where mean precipitation is further reduced over Europe when comparing MIS4 and MIS8 with LGM. The changes in the cyclone tracks and related precipitation changes in the Mediterranean for the summer season need to be assessed. Additionally, the effect of the orbital forcing on changes in cyclone tracks and associated precipitation changes in the North Pacific must be evaluated for both seasons.

 
Providing useful local climate information through statistical bias correction
Authors: Adakudlu Muralidhar , Xoplaki Elena , Paeth Heiko , Ibebuchi Chibuike , Schoenbein Daniel
Published: March 2022

Daily precipitation and temperature simulated by regional climate models carry large systematic biases owing to multiple factors including inadequate model resolution and limitations in the parameterization of important processes. Reduction of these biases is a crucial process in rendering the model information more reliable for climate change and hydrological assessments. We present an evaluative study of bias correction of daily precipitation and temperature from an ensemble of regional climate models from the EUR-11 CORDEX domain (CLMCOM-CCLM4, GERICS-REMO15, SMHI-RCA4, DMI-HIRHAM5, and CanRCM4 driven by MPI-ESM). This is an important milestone within a larger framework of the RegiKlim consortium towards generating high-resolution bias corrected and statistically downscaled fields for providing useful climate information in specific areas in Germany. A quantile delta mapping (QDM) approach is applied to adjust the biases in the distribution characteristics of precipitation and temperature. The delta factor, derived from the ratio of the projected value of a given quantile to that of the present value, is applied to the standard transfer function so that the modelled climate change signal can be preserved. High-resolution (0.1°) gridded dataset from the German Weather Service, DWD-HYRAS, is used as the reference for bias correcting the variables. The impact of the bias adjustment on important parameters such as the number and frequency of wet/dry and cold/hot spells are quantified. The response of the quantile mapping method to the seasonal variations in the dominant driving processes is further investigated. 
Improving High Resolution Ocean Reanalyses Using a Smoother Algorithm
Authors: Dong Bo , Haines Keith , Martin Matthew
Published: March 2022

We present a post-hoc smoothing algorithm for use with sequentially generated reanalysis products, utilizing the archive of “future” assimilation increments to update the “current” analysis. This is applied to the Lorenz 1963 model and then to the Met Office GloSea5 Global ¼° ocean reanalysis during 2016.  A decay time parameter is applied to the sequential increments which assumes that background error covariances remain spatially unchanged but decay exponentially away from analysis times. Only increments are smoothed so the reanalysis product retains modelled high-frequency variability, e.g., from atmospheric forcing. Results show significant improvement over the original reanalysis in the 3D temperature and salinity variability, as well as in the sea surface height (SSH) and ocean currents. Spatial gap filling from future data is particularly beneficial. The impact on the time variability of ocean heat and salt content, as well as kinetic energy and the Atlantic Meridional Overturning Circulation (AMOC), is demonstrated. 