bluuebunny/crossref_metadata_2025 huggingface dataset:
Digital Transformation of Critical Water Infrastructure
Authors: Konstantinidis Fotios , Michalis Panagiotis , Valyrakis Manousos
Published: March 2021

The ongoing fourth industrial revolution has accelerated the transformation of management and maintenance of assets into the digital era. This involves the application and interoperability of management systems in an upper system like the one described as Civil Infrastructure 4.0 [1]. CI4.0 involves the collection and process of data from the surrounding infrastructure over a wide range of assets and systems, incorporating a multi-integrated decision support system for efficient asset management. This is particular important for ageing water infrastructure as it is threatened by the occurrence of flood-related hazards, which have significant degradation impact and consequences to transport systems, e.g. bridges, embankments, waterways etc.

Despite the recent advances in the development and application of immersive technologies, transport and water infrastructure are still considered to be managed in a traditional way. This process involves on-site engineers making decisions based on their skills and experience, while in the majority of the times using paper-based analytics.

This study presents the development of intelligent tools to efficiently advance decision making about the maintenance procedure of water infrastructure, aiming to reduce costs and assessment times. One of the technological pillars, which can upgrade the traditional procedures is Augmented Reality (AR) technology, which is already used in other industries like Manufacturing and Automotive [2]. AR creates a combined environment in which the views of real and virtual worlds co-exist. AR technology provides valuable key information to inspectors, through AR glasses or mobile devices, pointing out areas of interest. Such an AR solution can register the coordination of location of the defects, analysing the possible maintenance solutions, and communicating effectively between in-house operators and inspectors on-site.

[1] Michalis, P., Konstantinidis, F. and Valyrakis, M. (2019). The road towards Civil Infrastructure 4.0 for proactive asset management of critical infrastructure systems. Proceedings of the 2nd International Conference on Natural Hazards & Infrastructure (ICONHIC), 23–26 June Chania, Greece, pp. 1-9.

[2] Konstantinidis, F.K., Kansizoglou, I., Santavas, N., Mouroutsos, S.G. and Gasteratos, A., 2020. MARMA: A Mobile Augmented Reality Maintenance Assistant for Fast-Track Repair Procedures in the Context of Industry 4.0. Machines, 8(4), p.88.
Analysis of a database of landslides triggered by the 2016 Central Italy seismic sequence  
Authors: Forte Giovanni , De Falco Melania , Iannicelli Federica , Santo Antonio
Published: March 2021

The seismic sequence that struck Central Italy in 2016 was characterized by three main shocks respectively occurred on August 24th Mw 6.0; October 26th Mw5.9 and October 30th Mw 6.5. The seismic sequence caused several ground effects over a large area of ​​the central Apennine mountain range, mainly affecting transportation routes.

In the aftermath of the sequence, several research groups mapped around 820 landslides involving road cuts in rock and fill slopes over an area of about 2000 km2 (GEER,ISPRA, C.E.R.I. by Roma La Sapienza). These data are summarized in the CEDIT catalog by Martino et al., (2017), where almost 150, 250 and 420 instability phenomena were respectively triggered by each mainshock. Further updates were carried out by the Authors in the framework of the Reluis projects of the Department of Civil Protection. In particular, other 550 phenomena were mapped by interpretation of aero photos provided by google-earth. For some of the largest ones, field surveys were carried out for mechanical, structural, and geometrical characterization.

The dataset distribution was analyzed with geological, geomorphological, and seismic parameters, such as lithology, fault distance, landslide run-out, estimates of mobilized volumes, distance from the epicenter, PGA, and damages.

The triggered events are mainly characterized by Category I of Keefer (1984) classification, namely rockfalls and rockslides. The maximum triggering distance resulted as high as 50 km far from the epicenter. The most affected areas are characterized by ridge crests or flanks of valleys in carbonate rocks.

This study permitted to highlight the most relevant parameters for the assessment of earthquake-triggered susceptibility for the study area and identify some meaningful and critical case studies for the future development of the research.

 
Strengths and limitations of sediment source fingerprinting in high mountain environments and relevance for soil restoration
Authors: Frankl Amaury , Evrard Olivier , Cammeraat Erik , Stokes Alexia
Published: March 2021

High mountain environments are among the most sensitive on Earth. Due to anthropogenic disturbances and climate change, rates of regolith mobilization due to for example landsliding have been accelerating recently. As a result, soils degrade, geohazards occur and flash floods have negative consequences in downstream areas. The restoration of soils in high mountain environments and an improved understanding of nature-based solutions to land degradation is, therefore, urgent. As finding the origin of erosion sources is a first step to improve mitigation strategies and guide the implementation of effective soil restoration measures, we discuss sediment source fingerprinting research in the context of soil restoration in high mountain environments. A literature review was done based on articles that apply sediment source fingerprinting in high mountain environments and additional articles on land use-based markers and soil restoration were used to develop an outlook for future research. The application of sediment provenance studies in high mountains environments has been limited so far. While some studies yield a rough distinction between sediment sources based on environmental radionuclides or elemental geochemistry, they cannot reflect multiple semi-natural vegetation types which are relevant source types that should be discriminated in high mountain environments. Therefore, we explore emerging techniques such as eDNA tracing that could potentially refine the information on the provenance of sediment based on land use and cover sources. Then, we will address the challenging hydro-geomorphic environment of high mountains and the implications for designing properly a sediment tracing study in such a context. We will conclude by presenting an outlook to guide future applications of sediment source fingerprinting in high mountain environments, where geohazards are imminent and soil restoration is urgent.

Key words: alpine, environmental DNA, erosion, landslide, vegetation
Modifications to the Effective Sample Area in Data Acquired by 2-Dimensional Video Disdrometers
Authors: Larsen Michael L. , Blouin Christopher K.
Published: March 2021

The 2-Dimensional Video Disdrometer (manufactured by Joanneum Research) is an instrument widely used for ground validation and precipitation microphysics studies. This instrument is capable of reporting back multiple properties of each detected hydrometeor; fields in the data record include arrival time, fall velocity, oblateness, mass-weighted equivalent diameter, detection position, and estimated detector sample area for each detected drop.

The last of these variables is necessary for using the data record to reliably estimate the instantaneous rain rate and total accumulations; it varies from detected drop to detected drop because a detected hydrometer must be fully enclosed within a fixed sample area to be successfully characterized by the instrument; this means that larger droplets have a smaller region that their centers can fall through and still be accurately measured. Careful analysis reveals that improvements can be made to the manufacturer’s calculation of this drop-dependent effective sample area.

These improvements are related to four key observations. (1) Due to the optical geometry of the instrument, not every pixel comprising the detection area has the same size. (2) The manufacturer’s algorithm makes some sub-optimal corrections for accounting for the detection area boundary. (3) The assumed extent of the full detection area field-of-view has been found to be slightly inaccurate. (4) There is a recently found anomaly that intermittently renders part of the detection area insensitive to reliable drop detection.

Here, we present a review of these observations, outline the structure of a simple post-processing algorithm developed to adjust the effective sampling area for each drop, and present results quantifying the overall impact on precipitation accumulations for a data record incorporating over 200 million detected raindrops.
Stratospheric mountain waves trailing across northern Europe
Authors: Dörnbrack Andreas
Published: March 2021

Planetary waves disturbed the hitherto stable Arctic stratospheric polar vortex mid of
January 2016 in such a way that unique tropospheric and stratospheric flow conditions
for vertically and horizontally propagating mountain waves developed. Co-existing
strong low-level westerly winds across almost all European mountain ranges plus the
almost zonally-aligned polar front jet created these favorable conditions for deeply
propagating gravity waves. Furthermore, the northward displacement of the polar night
jet resulted in a wide-spread coverage of stratospheric mountain waves trailling across
northern Europe. This paper describes the particular meteorological setting by
analyzing the tropospheric and stratospheric flows based on the ERA5 data. The
potential of the flow for exciting internal gravity waves from non-orographic sources is
evaluated across all altitudes by considering various instability indices as δ , Ro, Ro ζ , Ro⊥ ,
and Δ NBE.

The analyzed gravity waves are described and characterized in terms of
commonly used parameters. The main finding of this case study is the exceptionally
vast extension of the mountain waves trailing to high latitudes originating from the flow
across the mountainous sources that are located at about 45 N. As a useful addition to
the case study, tracks for potential research flights are proposed that sample the
waves by a vertically pointing airborne remote-sensing instrument. Benefits and
drawbacks of the different approaches to observe the meridional focussing of the
mountain waves into the polar night jet are discussed.

 
Sensitivity analysis to WRF parameterizations for mountain waves near Madrid airport (Spain)
Authors: Díaz Fernández Javier , Quitián Hernández Lara , Bolgiani Pedro , Santos Muñoz Daniel , Sastre Mariano , González Alemán Juan Jesús , Valero Francisco , Sebastián Martín Luis Ignacio , Lopez Laura , Farran Jose Ignacion , Martín María Luisa
Published: March 2021

Aircraft icing and turbulence associated with mountain waves events are adverse meteorological phenomena potentially affecting aviation safety and air traffic management. This study analyzes 13 mountain wave events in the vicinity of the Adolfo Suárez Madrid-Barajas airport (Spain) for two years (from 2017 to 2019). Mountain waves are formed in the leeward side of the Guadarrama mountains when the wind flows perpendicular to this orographic barrier (north-northwest winds). The thirteen events are simulated using several parameterizations from the Weather Research and Forecasting (WRF) model. Simulated pseudo-satellite images are validated using the observed brightness temperature from satellite images. Then, a sensitivity analysis is developed through several skill scores applied to brightness temperature in order to select the schemes best performing to forecast mountain waves. Finally, the best parametrization is used to assess several atmospheric variables involved in mountain waves formation. 

 
Contrasting responses of soil phosphatase activity to nitrogen and phosphorus loadings: Implications for phosphorus management
Authors: Chen Ji , Luo Yiqi , Cao Junji , Jørgensen Uffe , Moorhead Daryl , Sinsabaugh Robert L.
Published: March 2021

Human activity has caused imbalances in nitrogen (+N) and phosphorus (+P) loadings of ecosystems around the world, causing widespread P limitation of many biological processes. Soil phosphatases catalyze the hydrolysis of P from a range of organic compounds, representing an important P acquisition pathway. Therefore, a better understanding of soil phosphatase activity as well as the underlying mechanisms to individual and combined N and P loadings could provide fresh insights for wise P management. Here we show, using a meta-analysis of 188 published studies and 1277 observations that +N significantly increased soil phosphatase activity by 14%, +P significantly repressed it by 30%, and +N+P led to non-significant responses of soil phosphatase activity. Responses of soil phosphatase activity to +N were positively correlated with soil C and N content, whereas the reverse relationships were observed for +P and +N+P. Similarly, effects of +N on soil phosphatase activity were positively related to microbial biomass C, microbial biomass C:P, and microbial biomass N:P, whereas reverse relationships were observed for +P. Although we found no clear relationship between soil pH and soil phosphatase activity, +N-induced reductions in soil pH were positively correlated with soil phosphatase activity. Our results underscore the integrated control of soil and microbial C, N and P stoichiometry on the responses of soil phosphatase activity to +N, +P, and +N+P, which can be used to optimize future P management.
Development of scenarios for future emissions of chemicals from agricultural, industrial and urban systems
Authors: Nagesh Poornima , J. de boer Hugo , C. Dekker Stefan , P. van Vuuren Detlef
Published: March 2021

Water is an essential resource for human life and the environment. The widespread use of chemicals in daily life has led to significant water quality concerns. During the production phase, the use phase as well as after use, (residues of) these chemicals can enter the environment and water systems. Furthermore, the use and production of chemicals are increasing rapidly, driven by mainly population growth, urbanisation and economic growth. Increased use leads to further emissions of chemicals to water, posing significant water quality concerns. Henceforth there is an urgent need to understand the linkage between society and production and consumption of chemicals to explore possible changes in water quality.

Socio-economic scenario analysis is a useful tool to investigate the long-term consequences of future change and mitigation options. While scenarios have been broadly applied to understand air pollution, this not yet the case for chemical pollution to surface waters. In this work, we propose a general framework to develop scenarios for the future emissions of chemicals to water by using the Shared Socio-economic Pathways (SSP). The framework follows the basic elements of the scenario development process by defining the current system, describe the changes in emissions with scenario drivers and elaboration to the future. The framework is then tested on a set of selected ‘example’ chemicals that represent broader chemical groups of pharmaceuticals (Ibuprofen and Diclofenac), pesticides (Terbuthylazine) and industrial chemicals (Cadmium and Di-ethyl phthalate). Chemical emissions to water over the past years were used to understand their yearly trends and patterns over the European countries. Lastly, the emission scenarios for chemicals for 2050 were developed by using SSP drivers from the IMAGE Integrated assessment model as an input to the empirical emission models. The three SSP scenarios: SSP1 ("Sustainability"), SSP2 ("Middle of the Road") and SSP3 ("Regional Rivalry") focusing on Europe were included. Additionally, the developed scenarios also describe mitigation efforts.

The results of emission scenarios displayed an increase in emissions up to 2050 for the exemplary chemicals in Western Europe for all three scenarios SSP1, SSP2 and SSP3. While the emissions of chemicals linearly decreased in Eastern Europe for the same period. SSP3 showed the highest emissions in 2050 except for cadmium emissions from wastewater treatment plants. The results showed that the framework helps in understanding the possible influence of socio-economic changes on use and emissions of chemicals which can be a part of future risk assessments. While the framework can be extended similarly to other pharmaceuticals and pesticides, it requires a detailed understanding of complex emission sources for industrial chemicals.
Reconsidering the Variscan basement of southern Tuscany (inner Northern Apennines)
Authors: Capezzuoli Enrico , Spina Amalia , Brogi Andrea , Liotta Domenico , Bagnoli Gabriella , Zucchi Martina , Molli Giancarlo , Regoli Renzo
Published: March 2021

The Pre-Mesozoic units exposed in the inner Northern Apennines mostly consist of middle-late Carboniferous-Permian successions unconformably deposited on a continental crust consolidated at the end of the Variscan (i.e. Hercynian) orogenic cycle (Silurian-Carboniferous). In the inner Northern Apennines, exposures of this continental crust, Cambrian?-early Carboniferous in age, have been described in the Northern Tuscany, Elba Island (Tuscan Archipelago) and, partly, in scattered and isolated outcrops of southern Tuscany. In this contribution, we reappraise the most significative succession (i.e. Risanguigno Formation) exposed in southern Tuscany and considered by most authors as part of the Variscan Basement. New stratigraphic and structural studies, coupled with palynological analyses, allow us to refine the age of the Risanguigno Fm and its geological setting and evolution. Based on the microfloristic content, the structural setting and the fieldwork study, we attribute this formation to late Tournaisian-Visean (middle Mississipian) time interval and conclude it is not showing evidence of a pre-Alpine deformation. These results, together with the already existing data, allow us to presume that no exposures of rocks involved in the Variscan orogenesis occur in southern Tuscany.
Pressure drag for shallow cumulus clouds: from thermals to the cloud ensemble
Authors: Gu Jian-Feng , Plant Robert , Holloway Christopher , Muetzelfeldt Mark
Published: March 2021

This study takes the first step to bridge the gap between the pressure drag of a shallow cloud ensemble and that of an individual cloud composed of rising thermals. It is found that the pressure drag for a cloud ensemble is primarily controlled by the dynamical component. The dominance of dynamical pressure drag and its increased magnitude with height are independent of cloud lifetime and are common features of individual clouds except that the total drag of a single cloud over life cycle presents vertical oscillations. These oscillations are associated with successive rising thermals but are further complicated by the evaporation-driven downdrafts outside the cloud. The horizontal vorticity associated with the vortical structure is amplified as the thermals rise to higher altitudes due to continuous baroclinic vorticity generation. This leads to the increased magnitude of local minima of dynamical pressure perturbation with height and consequently to increased dynamical pressure drag.
Dancing Sprites Above a Lightning Mapping Array - an analysis of the storm and flash/sprite developments
Authors: Tomicic Maja , Soula Serge , Farges Thomas , Prieur Serge , Defer Eric
Published: March 2021

This study is a multi-instrumental analysis of a ~20-hour duration northwestern Mediterranean storm on September 21, 2019 that produced 21 sprites recorded with a video camera, of which 19 (90 %) were dancing sprites. A dancing sprite is a phenomenon in which sequences of sprites appear in succession with time intervals of no more than a few hundred milliseconds. For the most part, the individual sprites are a consequence of discrete strokes from one extended lightning flash. In this case, we find that 87.5% of the sprite sequences were triggered by distinct positive cloud-to-ground (+CG) strokes. The time between successive sprite parent (SP)+CG strokes within the same dancing sprite was between 40 and 516 ms, and the distance ranged between 2 and 87 km. The storm size and vertical development were analyzed from the infrared radiometer onboard Meteosat Second Generation satellite and the lightning activity was documented with several lightning location systems (LLS): the French LF network (Météorage), the GLD360 network operated by Vaisala company, the VHF SAETTA Lightning Mapping Array (LMA) system located in Corsica. Additionally, the vertical electric field at the time of the dancing sprites was measured with a broadband ELF vertical dipole whip antenna ~700 km away from the storm. The SAETTA LMA allows to map the SP+CG flashes in their both full extent and temporal evolution, and to infer the charge structure of the parent storm. We show that the SP+CG flashes followed a common propagation: they originated from the convective and very electrically active regions of the storm, and then escaped and extended horizontally far (tens of km) into the stratiform cloud region. Most of the sprites were triggered by +CG strokes in the stratiform region often following flash development resembling cutoff of a long negative leader. Additionally, we present a detailed analysis of two dancing sprite events in which the SP+CGs triggered new bidirectional breakdown with fast moving leaders that extended into the stratiform cloud region and resulted in new SP+CG strokes. In both events, we find in both LLS and ELF vertical electric field records, that the last sprite sequence was triggered by three almost simultaneous +CG strokes.
Investigation of failure and damage processes of andesitic rocks
Authors: Dinç Göğüş Özge , Yılmaz Deniz , Avşar Elif , Kayabalı Kamil
Published: March 2021

In this research, failure and deformation processes of andesitic rocks are investigated through laboratory and discrete element modeling (DEM) analysis to reveal the transition of the cracking, namely from microscale to mesoscale (lab scale). For this purpose, the mechanical properties of Ankara andesites were initially investigated by performing uniaxial - triaxial compressive and indirect tensile laboratory tests. Further, these properties were used as reference parameters for the calibration process in a numerical model, generated through a three-dimensional open source code (Yade) based on the discrete element method (DEM). Our results show that during the linear-elastic region of the stress-strain curve, the major mechanism of rock behavior is driven by tensile cracks. When the crack damage threshold is reached, as a result of plastic strain, the strength related to the inherent cohesion significantly decreases and damage in the rock cannot be prevented anymore. At the peak stress of the curve, both tensile and shear cracks accumulate, intensively. Even the mesoscale failure mechanism is controlled by shearing at the residual stage of the yielding, based on the micro-scale process in the DEM model, the number of micro shear cracks is very limited compared to the tensile ones. This finding shows that the friction takes the control of the damage process as the only driving force during residual phase time.  
Efficient Fourier-collocation method for full scattering data of Zakharov-Shabat periodic problem
Authors: Mullyadzhanov Ilya , Mullyadzhanov Rustam , Gelash Andrey
Published: March 2021

The one-dimensional nonlinear Schrodinger equation (NLSE) serves as a universal model of nonlinear wave propagation appearing in different areas of physics. In particular it describes weakly nonlinear wave trains on the surface of deep water and captures up to certain extent the phenomenon of rogue waves formation. The NLSE can be completely integrated using the inverse scattering transform method that allows transformation of the wave field to the so-called scattering data representing a nonlinear analogue of conventional Fourier harmonics. The scattering data for the NLSE can be calculated by solving an auxiliary linear system with the wave field playing the role of potential – the so-called Zakharov-Shabat problem. Here we present a novel efficient approach for numerical computation of scattering data for spatially periodic nonlinear wave fields governed by focusing version of the NLSE. The developed algorithm is based on Fourier-collocation method and provides one an access to full scattering data, that is main eigenvalue spectrum (eigenvalue bands and gaps) and auxiliary spectrum (specific phase parameters of the nonlinear harmonics) of Zakharov-Shabat problem. We verify the developed algorithm using a simple analytic plane wave solution and then demonstrate its efficiency with various examples of large complex nonlinear wave fields exhibiting intricate structure of bands and gaps. Special attention is paid to the case when the wave field is strongly nonlinear and contains solitons which correspond to narrow gaps in the eigenvalue spectrum, see e.g. [1], when numerical computations may become unstable [2]. Finally we discuss applications of the developed approach for analysis of numerical and experimental nonlinear wave fields data.

The work was supported by Russian Science Foundation grant No. 20-71-00022.

[1] A. A. Gelash and D. S. Agafontsev, Physical Review E 98, 042210 (2018).

[2] A. Gelash and R. Mullyadzhanov, Physical Review E 101, 052206 (2020).
The strength of the Earth’s magnetic field from Pre-Pottery to Pottery Neolithic, Jordan
Authors: Di Chiara Anita , Tauxe Lisa , Levy Thomas , Najjar Mohammand , Florindo Fabio , Ben-Yosef Erez
Published: March 2021

Constraining the secular variations of the Earth’s magnetic field strength in the past is fundamental to understanding short term processes of the geodynamo. Such records constitute a powerful and independent dating tool for archaeological sites and geological formations. In this study, we present 10 new and robust archaeointensity results from Pre-Pottery to Pottery Neolithic and, for one of the first times, flint (burnt chert) from Jordan. Two of these results constitute the oldest archaeointensity data for the entire Levant, ancient Egypt and Mesopotamia extending the archaeomagnetic dating reference for the Holocene. Virtual Axial Dipole Moments (VADM)s show that the Earth’s magnetic field in the Southern Levant was weak (about half the present field) at around 7,600 years BCE, recovering its strength to greater than the present field around 7,100 BCE and gradually weakening again around 5,200 years BCE. In addition, successful results obtained from burnt flint demonstrate the potential of this rarely used material in archaeomagnetic research, in particular for prehistoric periods from the first use of fire to the invention of pottery.
Biogenic native Sulfur linked to the Neogene deposits from the Riffian Corridors (Northern Morocco): preliminary study and characterization
Authors: Boubkari Laila , Raji Otmane , Achalhi Mohammed , Ouabid Muhammed , Bodinier Jean Louis
Published: March 2021

Elemental sulfur in sedimentary rocks is commonly associated with evaporites and authigenic carbonates. The genesis of this evaporite hosted native sulfur has been traditionally considered as a result of bacterial sulfate reduction under specific geological and paleogeographic conditions. Some biogenic sulfur occurrences are found in the Mediterranean area associated with the Neogene formations (e.g. Hellin, Lorca, Teruel, Sicily). They are described as interbedded layers in large evaporitic sequences or as sulfur nodules enclosed in secondary gypsum or carbonate deposits. Quite similar geological settings are present in Northern Morocco where several sediment-hosted sulfur showings were noted. However, these potential sulfur occurrences in the Pre-Rif and post-nappe Neogene basins have not been studied and still basically unknown. This work aims to explore these occurrences and assess their potentials using preliminary field, mineralogical and geochemical data. Several potential areas were identified at the Tortono-Messinian formations of Oued Amlil, Arbaa Taourirt, Taghzout Tassa, and Boudinar basins. They show favorable settings composed mainly of gypsiferous marls, carbonate, and organic matter-rich black sediments. In terms of sulfur contents, preliminary XRD data confirmed the presence of elemental sulfur and geochemical analyses show total sulfur content reaching 18.5 wt.%. However, further fieldwork combined with advanced mineralogical and isotopic geochemistry is still necessary for this area to try understanding their paragenesis in comparison with other similar Mediterranean occurrences.
Combining drone-derived digital elevation models and single grain luminescence data of modern analogue deposits to reveal sediment transport pathways and geomorphic change in washover fans
Authors: May Simon Matthias , Brill Dominik , Callow John Nikolaus , Hoffmeister Dirk , May Jan-Hendrik
Published: March 2021

The chronostratigraphy of coastal sedimentary records such as washover fans or beach-ridge sequences may be used to reconstruct storm chronologies on centennial to millennial time scales. However, modern analogues are crucial for interpretations of depositional processes and for reducing uncertainty in evaluating the typically complex chronostratigraphic architecture of these landforms. Such a modern analogue was provided by category 3 tropical cyclone (TC) Olwyn in 2015, which caused a significant storm surge in the Gulf of Exmouth, Western Australia, and which activated large washover fans located in the southwestern part of the Gulf. Pre- and post-TC Olwyn geomorphological surveys and high-resolution drone-derived topographical data of one of these washover fans document a detailed history of erosion and deposition during the event. The modern analogue deposits provided an excellent opportunity to evaluate the use of luminescence-based proxies (luminescence inventories) including quartz single-grain age distributions and associated remnant ages, as well as quartz and feldspar luminescence signal comparisons for tracing event-related sediment source environments and understanding transport processes (May et al., 2020). Sediments deposited during Olwyn show a systematic relationship between luminescence characteristics and washover fan position. Seaward and central washover sections are indicated by well-bleached deposits due to the beach as the dominant source and/or long transport distances across the fan. Lateral washover deposits, in contrast, are characterised by rather local source areas and short transport distances, resulting in higher remnant ages of 70-140 a. This data shows that the combination of sediment source environments and sediment transport length across the fan represents the main control in resetting the luminescence signal and enabling reliable depositional ages to be calculated. It documents the benefit of investigating luminescence inventories when establishing chronologies from complex sedimentary records, thereby demanding a careful consideration of local processes and source areas when interpreting sedimentary TC records.

May, S. M., Callow, J. N., Brill, D., Hoffmeister, D., & May, J.-H. (2020). Revealing sediment transport pathways and geomorphic change in washover fans by combining drone-derived digital elevation models and single grain luminescence data. Journal of Geophysical Research: Earth Surface, 125, e2020JF005792. https://doi.org/10.1029/2020JF005792
Seasonal and Mesoscale Variability of the Two Atlantic Water Recirculation Pathways in Fram Strait
Authors: Hofmann Zerlina , von Appen Wilken-Jon , Wekerle Claudia
Published: March 2021

Atlantic Water, which is transported northward by the West Spitsbergen Current, partly recirculates (i.e. turns westward) in Fram Strait. This determines how much heat and salt reaches the Arctic Ocean, and how much joins the East Greenland Current on its southward path. We describe the Atlantic Water recirculation's location, seasonality, and mesoscale variability by analyzing the first observations from moored instruments at five latitudes in central Fram Strait, spanning a period from August 2016 to July 2018. We observe recirculation on the prime meridian at 78°50'N and 80°10'N, respectively south and north of the Molly Hole, and no recirculation further south at 78°10'N and further north at 80°50'N. At a fifth mooring location at 79°30'N, we observe some influence of the two recirculation branches. The southern recirculation is observed as a continuous westward flow that carries Atlantic Water throughout the year, though it may be subject to broadening and narrowing. It is affected by eddies in spring, likely due to the seasonality of mesoscale instability in the West Spitsbergen Current. The northern recirculation is observed solely as passing eddies on the prime meridian, which are strongest during late autumn and winter, and absent during summer. This seasonality is likely affected both by the conditions set by the West Spitsbergen Current and by the sea ice. Open ocean eddies originating from the West Spitsbergen Current interact with the sea ice edge when they subduct below the fresher, colder water. Additionally the stratification set up by sea ice presence may inhibit recirculation.
A rare free silica-bearing micrometeorite
Authors: Fernandes Dafilgo
Published: March 2021

Extraterrestrial dust that reaches the Earth’s surface has shown to represent the diverse types of samples from different precursors, namely, asteroid complexes and cometary bodies from the solar system. A substantial amount of this dust that strikes the upper atmosphere is believed to have been lost due to frictional heating with air molecules. Cosmic spherules that are melted particles are some of the widely recognized micrometeorites that survived this catastrophic entry process; however, their primordial characteristics are altered from their precursors making it difficult to identify the precursors. An individual peculiar spherule MS-I35-P204 recovered from the Antarctica blue ice has been identified. The spherule has been segregated using magnetic separation method, mounted in epoxy, and examined using SEM, subsequently analysed under electron microprobe. It is surrounded by a thin magnetite rim, and also holds a single kamacite bead that protrudes out at its top. The interior mineralogy mostly constitutes of a bulk pyroxene normative glass (MnO>2wt%) with several vesicles. The rare mineral phase is a skeletal aggregate of free silica, bearing Fe nuggets embedded in a glass. An isolated narrow lath of forsterite appears to be chondritic and is observed as relict grain that is associated with an anomalous low Ca pyroxene (MnO ~1.3 wt%, FeO~13 wt%). Earlier, free silica has been reported in some chondritic meteorites particularly the Enstatite and Ordinary group, and also in some carbonaceous chondrites such as CM, CR, CH, and K. It profoundly forms a pod that encloses the ferromagnesian silicate in silica-bearing chondrules. The unusual mineral assemblage seen in this spherule thereby appears to constrain probably the unique type of its contributor which need to be studied.
More extreme El Niño events reduce ocean carbon uptake in the future
Authors: Liao Enhui , Resplandy Laure , Liu Junjie , Bowman Kevin
Published: March 2021

El Niño events weaken the strong natural oceanic source of CO2 in the Tropical Pacific Ocean, partly offsetting the simultaneous release of CO2 from the terrestrial biosphere during these events. Yet, uncertainties in the magnitude of this ocean response and how it will respond to the projected increase in extreme El Niño in the future (Cai et al., 2014) limit our understanding of the global carbon cycle and its sensitivity to climate. Here, we examine the mechanisms controlling the air-sea CO2 flux response to El Niño events and how it will evolve in the future, using multidecadal ocean pCO2 observations in conjunction with CMIP6 Earth system models (ESMs) and a state‐of‐the‐art ocean biogeochemical model. We show that the magnitude, spatial extent, and duration of the anomalous ocean CO2 drawdown increased with El Niño intensity in the historical period. However, this relationship reverses in the CMIP6 projections under the high emission scenario. ESMs project more intense El Niño events, but weaker CO2 flux anomalies in the future. This unexpected response is controlled by two factors: a stronger compensation between thermally-driven outgassing and non-thermal drawdown (56% of the signal); and less pronounced wind anomalies limiting the impact of El Niño on air-sea CO2 exchanges (26% of the signal). El Niños should no longer reinforce the net global oceanic sink in the future, but have a near-neutral effect or even release CO2 to the atmosphere, reinforcing the concurrent release of CO2 from the terrestrial biosphere.
Lp LOSC-Support Vector Machines for Regression Estimation and their Application to Geomatics
Authors: Wong Jeff Chak Fu , Yu Tsz Fung
Published: March 2021

The classification of vertical displacements and the estimation of a local geometric geoid model and coordinate transformation were recently solved by the L2 support vector machine and support vector regression. The Lp quasi-norm SVM and SVR (0
Different microplastics versus different bottom sediments: transport and accumulation pattern in the open-channel flow experiments
Authors: Isachenko Igor , Chubarenko Irina
Published: March 2021

Initiation of motion, resuspension, transport, and accumulation of microplastic particles (MPs) at the sea bottom are prescribed by their physical properties – density, size, and shape, as it is known for natural sediment grains. However, from sedimentological approaches, not much can be said about the behavior of non-spherical particles at the bottom covered by another type of material. Thus, experimental disclosure of general features of the MPs transport and accumulation pattern should aid a lot further theoretical description of such a complex process.

Laboratory experiments on the MPs transport by the open-channel flow and their accumulation in regions with various bottom roughness were carried out in 10 m long and 0.33 m wide hydrodynamic flume. The bottom had 4 sections (ca. 2 m long each) with the roughness increasing downstream: smooth-bottom section, followed by the sections covered by natural calibrated coarse sand (particle diameter 1-1.5 mm), marine granules (3-4 mm), and small pebbles (1-2 cm). The upper sediment surface was carefully horizontally leveled. The set of MPs included 1d (flexible and rigid), 2d (square/round/elongated; flexible/rigid), and 3d (round/cubic) particles made of polystyrene, polyester, polyamide (nylon), and polyethylene terephthalat (material density ranging from 1.05 to 1.41 g/cm3). Principal sizes of MPs ranged from 0.5 mm (smaller than the smallest sediment grain) to 5 cm (larger than the largest sediment grain). At the beginning of the experiment, MPs were placed on the smooth bottom. Thereafter, the flow rate was increased step-by-step by small increments. At each step, after at least 5 min since the last particle movement, the coordinates of the particles in their (new) stationary positions were registered.

Although we did not aim to achieve a similarity between a laboratory experiment and natural conditions, the results of the present study can be useful for a qualitative interpretation of field observations and further theoretical efforts. The results show, that the initiation of motion of particular MPs is dependent both on MPs size and the sediment characteristics. The cumulative curve, integrating coordinates of all the kinds of MPs in their stationary locations at all the flow steps, indicates the potential for the existence of MP accumulation zones in the regions right after the change in the bottom roughness, at the side of coarser sediment.

Investigations are supported by the Russian Science Foundation, grant No 19-17-00041.
Drought influences the phytolith morphology variation and its occluded carbon of leaves in Dendrocalamus Ronganensis during growing season
Authors: Li Rencheng , Wen Mengdan , Tao Xinyue , Vachula Richard S. , Tan Shuhui , Dong Haiyan , Zhou Lintong
Published: March 2021

Abstract: Being an important carbon (C) sink on Earth, phytolith occluded carbon (PhytOC) has been investigated in various soil-plant systems. Yet, the environmental factor (i.e., drought) is less studied on the variation of phytolith, its relative depositions in plant tissues, morphology variations, and occluded carbon in the soil-plant systems. In this study, we analyzed the monthly variations of phytolith production and phytolith-occluded carbon (PhytOC) in the leaves of Dendrocalamus ronganensis grown on a karst mountain in southwestern China. This study aimed to understand the drought factors influencing phytolith formation, morphology variation and carbon sequestration in plants. Our results showed that the phytolith assemblages and PhytOC between new and old leaves were significantly different, and varied with plant growth stages. The average PhytOC of old leaves and new leaves was 3.2% and 2.2%, respectively. In particular, both PhytOC and proportions of elongate, cuneiform and stomata phytolith in new leaves significantly decreased during drought months (from September to November). This study suggests that PhytOC in plants is closely related to phytolith morphologies, and significantly affected by growth stage and hydrologic conditions of the growth environment. This indicates that we can improve the efficiency of phytolith carbon sequestration in plants and potentially reduce the atmospheric carbon dioxide content by improving the soil water conditions required for plant growth.

Keywords: Dendrocalamus ronganensis; phytolith; phytolith-occluded carbon; soil drought
Mathematical model of a non-stationary process of accumulation of gas hydrates, confined to deep-water mud volcanoes
Authors: Sobisevich Alexey L. , Suetnova Elena I. , Zhostkov Ruslan A.
Published: March 2021

Large amounts of methane hydrate locked up within marine sediments are associated to mud volcanoes. We have investigated by means of mathematical modeling the unsteady process of accumulation of gas hydrates associated with the processes of mud volcanism. A mathematical model has been developed. The system of equations of the model describes the interrelated processes of filtration of gas-saturated fluid, thermal regime and pressure, and accumulation of gas hydrates in the seabed in the zone of thermobaric stability of gas hydrates. The numerical simulation of the accumulation of gas hydrates in the seabed in the deep structures of underwater mud volcanoes has been carried out using the realistic physical parameters values. The influence of the depth of the feeding reservoir and the pressure in it on the evolution of gas hydrate accumulations associated with deep-sea mud volcanoes is quantitatively analyzed. Modeling quantitatively showed that the hydrate saturation in the zones of underwater mud volcanoes is variable and its evolution depends on the geophysical properties of the bottom environment (temperature gradient, porosity, permeability, physical properties of sediments) and the depth of the mud reservoir and pressure in it. The volume of accumulated gas hydrates depends on the duration of the non-stationary process of accumulation between eruptions of a mud volcano. The rate of hydrate accumulation is tens and hundreds times the rate of hydrate accumulation in sedimentary basins of passive continental margins.
Urban flood modelling and sensitivity analysis: water exchange between the ground surface and the underground sewer network
Authors: González Andrés , Willems Patrick
Published: March 2021

Most 1D-2D urban drainage models simplify the water exchange process between the ground surface and the underground sewer network. They assume that surface runoff enters directly into the sewer network without modelling the initial overland flow. Moreover, surface flooding is only seen as the result of sewer network overflows, neglecting that it can also occur due to limitations of street inlets draining capacity. In fact, it is a common practice to ignore street inlets and to assume that water exchange occurs exclusively through manholes, which in reality, can have water transfers (sewer overflow) only after the displacement of their covers. These simplifications, do not allow to determine which water exchange processes have a greater impact in the occurrence of surface flooding.

This study developed a more realistic model representation of the urban drainage system (including street inlets and initial overland flow) and carried out a thorough sensitivity analysis of the parameters controlling water exchange processes. A combination of Latin-Hypercube (LH) and One-factor-At-a-Time (OAT) sampling techniques were used to measure global and local sensitivities. Brederode neighborhood in Antwerp (Belgium), a flat area that frequently suffers from pluvial flooding, was used as a study case. Results show that the inclusion of street inlets reduces the calculated total surface flood volume in simulations with design storms ranging from low to high return periods (T5-T100). It was also found that parameters controlling surface drainage are the most sensitive, with the street inlets clogging coefficient obtaining the highest sensitivity index value. Parameters controlling reverse flow showed almost null sensitivity.

Given that the draining processes are most sensitive (particularly street inlets clogging) to the occurrence of surface flooding, urban drainage models should explicitly include manholes and street inlets in their configuration. Moreover, it is recommended to apply rainfall directly on 2D mesh elements representing streets and open areas (for runoff produced on rooftops, use sub-catchment units). In this way, models can account for initial overland flow and properly assess the street inlets' drainage capacity.
Thunderstorm Classification Functions Based on Instability Indices and GNSS IWV for the Sofia Plain
Authors: Guerova Guergana , Dimitrova Tsvetelina , Georgiev Stefan
Published: March 2021

Bulgaria is a country with a high frequency of hail and thunderstorms from May to September. For the May–September 2010–2015 period, statistical regression analysis was applied to identify predictors/classification functions that contribute skills to thunderstorm forecasting in the Sofia plain. The functions are based on (1) instability indices computed from radiosonde data from Sofia station F1, and (2) combination of instability indices and Integrated Water Vapor (IWV), derived from the Global Navigation Satellite System (GNSS) station Sofia-Plana, F2. Analysis of the probability of detection and the false alarm ratio scores showed the superiority of the F2 classification function, with the best performance in May, followed by June and September. F1 and F2 scores were computed for independent data samples in the period 2017–2018 and confirmed the findings for the 2010–2015 period. Analysis of IWV and lightning flash rates for a multicell and supercell thunderstorm in June and July 2014 showed that the monthly IWV thresholds are reached 14.5 and 3.5 hours before the thunderstorm, respectively. The supercell IWV peak registered 40 min before the thunderstorm, followed by a local IWV minimum corresponding to a peak in the flash rate. In both cases, an increase of IWV during severe hail was registered, which is likely related to the hydrometeor contribution to GNSS path delay. The results of this study will be integrated into the Bulgarian Integrated NowCAsting tool for thunderstorm forecasting in the warm/convective season.