bluuebunny/crossref_metadata_2025 huggingface dataset:
Machine Learning Classification of Dust Impact Signals Observed by The Solar Orbiter Radio and Plasma Waves Instrument
Authors: Kvammen Andreas , Mann Ingrid , Kociscak Samuel
Published: March 2022

We present results from automatic classification of dust waveforms observed by The Solar Orbiter Radio and Plasma Waves Instrument.

Every day, several dust particles impacts the Solar Orbiter as the probe travels trough the inner heliosphere. The dust impact produces a cloud of electrons and ions on the spacecraft surface and the free charge causes a sharp and characteristic voltage signal, which decays towards the equilibrium potential after a few milliseconds via interaction with the ambient plasma. Detection and analysis of the characteristic dust waveform can be used to map the density, size and velocity distribution of dust particles in the inner heliosphere, and thus enhance our understanding of the role of dust in the solar system. Such statistical analysis do however require reliable dust detection software.

It is challenging to automatically detect and separate dust waveforms from other signal shapes by "hard coded" algorithms. Both due to spacecraft charging, causing variable shapes of impact signals, and since electromagnetic waves (such as solitary waves) may induce resembling voltage signals. Here we present results of waveform classification using various supervised machine learning techniques, where manually classified data is used both to train and test the classifiers.

We investigate automatic machine learning classification as a possible tool to make statistical analysis of the distribution of dust in the inner heliosphere more reliable and easier to conduct. Furthermore, the classifier may possibly be used on data (after pre-processing) from other spacecrafts with similar instruments, such as the Parker Solar Probe (PSP), the Solar Terrestrial Relations Observatory (STEREO) and the Magnetospheric Multiscale (MMS) mission.
Using the Nature-Based Solutions for Applying Circular Economy for the Construction Materials Sector in Egypt 
Authors: Marey Heba , Szabó György , Kozma Gábor
Published: March 2022

 

Abstract

The challenges posed by the growth of urbanization in Egypt and the development of new cities play an essential role in applying the circular economy (CE) in the construction materials sector and the priorities for promoting sustainable construction activities in the future. Therefore, the construction sector has many adverse environmental impacts on energy and natural resources consumption. Starting from materials production, operation until disposal to landfills. Consequently, the industry is considered one of the most consumers of non-renewable resources and producer of CO2 emissions. On the other hand, applying Nature-based solutions (NbS) to enhance sustainability by protecting the ecosystems and maintaining economic benefits plays a vital role, especially for new Egyptian cities. The research aims to investigate the role of applying NbS for achieving CE in construction materials and eliminate its negative impact in the scope of three factors:  green building materials, waste management systems, renewable energy use. The current research attempts to answer how NbS can improve the CE and reduce environmental impacts of the construction materials sector. Therefore, the SOWT analysis investigated the strengths, opportunities, weaknesses, and threats of using the NbS strategies for three different construction sites in Egypt. Furthermore, the survey questionnaire was applied to identify the interactions between the parameters derived from 40 participants such as consultants, architecture engineers, civil engineers, site engineers, project managers and review the previous research efforts. As a result, a conceptual framework was created for the construction materials considering reduce, reuse, recycle, recovery, and disposal, to identify the impact of the implementation of NbS on achieving sustainable development strategies in the Egyptian construction sector. The result showed that the NbS could effectively promote the construction sector and achieve environmental and economic benefits, which consequently help the transition to CE. Therefore, there is the necessity for developing new sustainable policies and cooperation between public and private sectors to support the investments of sustainable strategies in the construction materials market and increase Egyptian society's awareness of the benefits of NbS in economic, environmental, and social aspects.

 Keywords, Nature-based solution, Construction materials, Circular Economy, Egypt 
3D Scattering and Absorption model during the 2016-2017 Central Italy Seismic Sequence
Authors: Gabrielli Simona , Akinci Aybige , Napolitano Ferdinando , Del Pezzo Edoardo , De Siena Luca
Published: March 2022

The Amatrice-Visso-Norcia seismic sequence struck the Central Apennine (Italy) in 2016. Previous works brought to light how fluid movements likely triggered the sequence and reduced the stability of the normal fault network following the first earthquake (Amatrice, Mw6.0), and the subsequent events of Visso (Mw5.9) and Norcia (Mw6.5) mainshocks.
Seismic attenuation has the potential to visualize fluids presence and fractures in a seismic sequence and to image the effect of fluid migration in the events nucleation.

This work aims to provide 3D images of scattering and absorption at different frequency bands for two datasets, one before the sequence (March 2013-August 2016) and a second from the Amatrice-Visso-Norcia sequence (August 2016-January 2017). To measure scattering and absorption we used peak delay mapping and coda-attenuation tomography, respectively.
Previous 2D imaging of scattering and absorption showed a difference between the pre-sequence and the singular sequences at different frequency bands. Structural discontinuities and lithology control scattering losses at all frequencies, while a single high-absorption anomaly developed NNW-SSE across the seismogenic zone during the seismic sequence, probably related to the migration of deep-CO2 fluids from a deep source of trapped CO2 near the Amatrice earth.
The 3D preliminary results are in agreement with the 2D mapping, with high-scattering anomalies following the main structural and lithological elements of the Central Apennines (e.g. Monti Sibillini thrust), both during the pre-sequence and the sequence, also in depth. As for the 2D, the high absorption anomaly is widespread in the area before the Amatrice event, while it is mainly focused on the seismogenic zone during the sequence. This spatial expansion can be related to the deep migration of CO2-bearing fluids across the fault network also at seismogenic depths.
Using a natural laboratory to quantify sediment mobility in the turbulent wake of instrument frames and offshore infrastructure. 
Authors: Unsworth Christopher , Austin Martin , Van Landeghem Katrien
Published: March 2022

Predicting sediment transport near the threshold of mobility is a particular challenge in coastal environments, due in part to turbulence in the wake of bedforms and infrastructure but also due to variable grain size distributions and biological processes affecting mobility. Understanding the relevant processes and having the ability to accurately predict sediment transport in shallow shelf seas are currently of pivotal importance due to the prevalence of offshore wind infrastructure being built on mobile seabeds with mixtures of sediment grain sizes.  

Bridging the gap between the small-scale detail of sediment transport to large-scale modelling is a key challenge for the community. Using a set of novel observations of suspended sediment concentration (via a multifrequency acoustic backscatter system) and turbulence (via Nortek’s Aquadopp High Resolution Doppler Profiler) from a coastal site (~15 m depth) with sandy bed sediments, we revisit the threshold of motion from the perspective of Grass’ 1970’s work by investigating the overlaps of bed shear stress and initiation of motions for the bed sediments. A section of electricity cable was attached to the seabed instrument frame so that on ebb tides turbulent wakes and sediment suspensions from interactions with the cable and frame were measured, and on flood tides a clear boundary layer flow was measured.

We create a distribution of initiation of motions from bed sediment data, and from the ADCP data we calculate distributions of bed shear stresses using a temporal filter based on the large eddy turnover time. We investigate the overlap between the two distributions to assess the temporal mobility of the sediments, and discuss how estimating these distributions (and their overlap) can be an important way of improving our predictive capability of sediment transport beyond the usual median grain size and bed shear stress methods – especially important when there are turbulent wakes from bedforms and sea bed infrastructure.
Simulated formation of grounding-zone wedges and implications for ice-sheet stability
Authors: Damsgaard Anders , Suckale Jenny , Piotrowski Jan
Published: March 2022

Glacier flow has the potential to mobilize subglacial till, resulting in till deposition and subglacial landforms in glaciated areas. The subglacial till transport occurs when sedimentary beds are thawed and sufficiently weak relative to the glacial driving stress. As a consequence of till mobilization, soft-bedded and marine-terminating ice sheets are known to produce grounding-zone wedges. It has been hypothesized that these wedges may stabilize grounded ice in spite of rising sea level.

In order to test this hypothesis, we develop a fully coupled framework for simulating ice flow, glacier hydrology, and till advection. Ice flow and hydrology is handled with PISM, the three-dimensional, thermomechanical, parallel ice sheet model (Bueler and Brown, 2009; Winkelmann et al 2011). Till advection is computed with the cohesive non-granular fluidity method with pore-water pressure, which is consistent with Coulomb-frictional mechanics and stress-dependent shear-zone thickness (Damsgaard et al., 2020). We apply the model to various bed geometries and forcing scenarios, and show how subglacial landforms evolve and grounding-zone wedges form. The grounding-zone wedges prove to contribute conditional stabilization to the ice sheet, and this mechanism could limit the marine-ice sheet instabilities that may occur on reverse sloping beds.

 

References:

Bueler, E. and Brown, J. 2009 “Shallow shelf approximation as a “sliding law” in a”. J. Geophys. Res. Earth Surf. 114(F3)

Damsgaard, A., L. Goren and J. Suckale 2020 “Water pressure fluctuations control variability in sediment flux and slip dynamics beneath glaciers and ice streams”. Commun. Earth Environ. 1(66), 1–8. doi: 10.1038/s43247-020-00074-7

Winkelmann, R., M. A. Martin, M. Haseloff, T. Albrecht, E. Bueler, C. Khroulev and A. Levermann 2011 “The Potsdam Parallel Ice Sheet Model (PISM-PIK) - Part 1: Model description”. 5(3), 715–726. doi: 10.5194/tc-5-715-2011
Log-normal Approximation of Floc Size Distribution for Advection in Size-resolved Sediment Transport Modeling
Authors: Fang Zheng , Xu Fanghua
Published: March 2022

The transport of cohesive sediments in estuaries and coastal oceans can be simulated by coupling flocculation models with circulation models. Since size-resolved flocculation models allow the dynamic evolution of floc size distribution, these types of models can well characterize the transport and fate of cohesive sediments in water columns. However, due to the addition of tens of floc variables, the computational cost of these types of models is extremely high and has limited their application in real environments.

To improve the calculation efficiency, we proposed an efficient and accurate method for the representation of floc size distributions (FSD) in sediment transport models. A log-normal approximation of the floc size distribution is obtained by fitting the FSD with three parameters: the total mass concentration , the medium floc size  and the standard deviation parameter . The approximation is used for advection in circulation models. Instead of advection of floc concentration in each size bin, the  and the  are advected. After the advection is done, the FSD on each grid is obtained from the new and  as well as the constant .

Applications of the method in simulations of cohesive sediment transport in an idealized estuary for aggregation, breakup, gravitational settling and tidal mixing are described. The results are compared to results from the same simulation but without the log-normal approximation. According to these comparisons, the new method can improve the calculation efficiency by about 50%, and the differences are less than 10%. So the method has a great potential to be applied in size-resolved cohesive sediment transport modeling.
The extraction of urbanized areas based on the high-resolution night lights images: A case study in Barcelona, Spain  
Authors: Zheng Qianhui , Roca Josep
Published: March 2022

The definition of urbanized areas, both regionally and globally, is an important basis for urban development monitoring and management, as well as an important condition for studying social policies, economics, culture and the environment.

Thanks to the development of science and technology, urban expansion is developing rapidly. The method of extracting urbanized areas quickly and accurately has become the focus of research.

In the 1970s, with the beginning of the Defense Meteorological Satellite Program (DMSP), the images of night lights that provide a new method for the extraction of urbanized areas were born.

However, due to the limits of spatial resolution and spectral range, it’s true that there are defects in urbanized area extraction based on OMSP-OLS nightlight images.

In recent years, with the development of remote sensing technology, remote sensing data with a higher resolution emerged, providing an effective and applicable data source for urban planning monitoring.

I suppose that the images of night lights with a higher resolution have greater precision than the old ones in the extraction of urbanized areas.

This work has dedicated the images of night lights (NPP-VIIRS and Luojia1-01) and the images of urbanized areas (FROM-GLC 2017) to construct a logistic regression model to evaluate and compare the accuracy of the two images of night lights in the extraction of urbanized areas.

The case study is Barcelona metropolitan area, Spain. (636 km2, 3.3 million inhabitants).
Importance of secondary ice production over a large temperature range in Arctic mixed-phase clouds
Authors: Pasquier Julie Thérèse , Ramelli Fabiola , David Robert Oscar , Wieder Jörg , Li Guangyu , Lauber Annika , Lohmann Ulrike , Carlsen Tim , Gierens Rosa , Maturilli Marion , Henneberger Jan
Published: March 2022

The cloud radiative feedbacks are particularly complex and uncertain in the Arctic, which is a region of amplified warming. Within mixed-phase clouds (MPCs), the radiation fluxes are influenced by the thermodynamic phase and cloud particle concentrations. However, the processes responsible for ice crystal formation, particularly secondary ice production (SIP) processes, are still poorly understood.

We conducted in-situ cloud microphysical measurements in Ny-Ålesund, Svalbard, as part of the Ny-Ålesund AeroSol Cloud ExperimeNT campaign (NASCENT, Pasquier et al., BAMS, in revision). The main instrument used was a holographic cloud probe mounted on a tethered balloon system to image cloud particles. Additionally, ambient ice nucleating particles (INPs) and cloud condensation nuclei (CCN) were measured at ground level, remote sensing instruments (e.g. cloud radar) profiled the entire troposphere, and radiosondes were launched to determine the in-cloud temperature profiles.

Here we discuss the SIP occurrence in Arctic MPCs measured in autumn 2019 and spring 2020. We defined local SIP as occurring when the concentration of pristine ice crystals smaller than 100 µm in diameter is larger than the INP concentration. During the six days of measurements in MPCs, regions with local SIP were observed in 40% of the in-cloud measurements. Regions with high concentrations of small pristine ice crystals (>10 L-1) coincided with the presence of large frozen and broken drops, providing evidence for SIP during the freezing of drizzle drops. We suggest that the formation of drizzle drops initiating high SIP upon freezing was determined by the low CCN concentration in the pristine Arctic environment. Furthermore, SIP occurred at all observed temperatures (-24 °C to -2 °C). The frequency of SIP occurrence was highest in the temperature range between -24 °C and -18 °C (up to 96%), whereas the concentration of small pristine ice crystal peaked between -5 °C and -3 °C (up to 95 L-1). Our observations demonstrate the high importance of SIP for ice crystal formation in Arctic MPCs over a larger temperature range. Thereby, SIP influences the radiative properties of Arctic MPCs and hence the surface radiative energy budget.
Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment (LIAISE) Project: Overview of the Field Campaign intense phase
Authors: Boone Aaron , Best Martin , Bellvert Joaquim , Brooke Jennifer , Canut-Rocafort Guylaine , Cuxart Joan , Hartogensis Oscar , Ramon Miro Josep , LeMoigne Patrick , Polcher Jan , Price Jeremy , Quintana Segui Pere
Published: March 2022

It is known that irrigation can impact the local atmospheric boundary layer characteristics, thereby modifying near surface atmospheric conditions within and downwind of irrigated areas and potentially the recycling of precipitation. The understanding of the impact of anthropization and its representation in models have been inhibited due to a lack of consistent and extensive observations, but in recent years, land surface and atmospheric observation capabilities have advanced. The overall objective of the Land surface Interactions with the Atmosphere over the Iberian Semi-arid Environment (LIAISE) project is to improve the understanding and prediction of land-atmosphere-hydrology interactions in a semi-arid region characterized by strong surface heterogeneity between the natural landscape and intensive agriculture. The study region is located over the Pla d’Urgell region within the Ebro basin in NE Spain. This area was selected since it is a breadbasket region: there are discussions underway to further expand this irrigated zone owing to its economic importance, but consensus of current climate projections predicts a significant warming and drying over this region in upcoming years. Thus there is an urgent need to improve the prediction of the potential changes to the regional water cycle since water resources are limited.

 

Here we present an overview of the intense phase of the LIAISE observational campaign, which is part of the HYdrological cycles in the Mediterranean Experiment (HyMeX) phase 2, that took place in July, 2021 when land surface heterogeneity was at a maximum. A network of 7 stations provided continuous measurements of the surface energy and water budget components for multiple representative land cover types, including irrigated surfaces, along with detailed surface biophysical measurements from the leaf to field scale. Surface fluxes at the field scale were made using scintillometer configurations over 3 of the sites. Lower atmospheric measurements were obtained from tethered balloons, lidar, UHF profilers, frequent radio-sounding releases, UAVs and several aircraft. Finally, airborne instruments measured solar induced florescence, surface temperature over several spectral bands and soil moisture over a transect cutting across the rain-fed and irrigated areas. The main outcome of this project is to provide the underpinnings for improved models leading to better water resource impact studies for both the present and under future climate change.
Heat Transfer through Grass: A Diffusive Approach
Authors: Van de Wiel Bas , van der linden Steven , Kruis Maarten , Hartogensis Oscar , Moene Arnold , Bosveld Fred
Published: March 2022

Heat transport through short and closed vegetation, such as, grass is modelled by a

simple diffusion process. The grass is treated as a homogeneous ``sponge layer'' with

uniform thermal diffusivity and conductivity, placed on top of the soil. The temperature

and heat flux dynamics in both vegetation and soil are described using harmonic

analysis. All thermal properties have been determined by optimization against

observations from the Haarweg station in the Netherlands. Our results

indicate that both phase and amplitude of soil temperatures can be accurately

reproduced from the vegetation surface temperature. The diffusion approach requires

no specific tuning to, e.g., the daily cycle, but instead responds to all frequencies

present in the input data, including quick changes in cloud cover and day-night

transitions. The newly determined heat flux at the atmosphere-vegetation interface is

compared with the other components of the surface energy balance. The budget is

well-closed, particularly in the most challenging cases with varying cloud cover and

during transition periods. We conclude that the diffusion approach is a promising and

physically consistent alternative to more ad-hoc methods, like ``skin resistance''

approaches for vegetation and bulk correction methods for upper soil heat storage.

However, more work is needed to evaluate parameter variability and robustness under

different climatological conditions. From a numerical perspective, the multi-frequency

description allows for studying cases where the atmospheric boundary layer and the

top-surface interact on sub-hourly timescales. It would therefore be interesting to

couple the current land-surface description to turbulent resolving methods, such as,

large-eddy simulations.
New insights from fluorescent organic matter in natural cave systems and active speleothems: a one-year monitoring study from Northwestern Spain
Authors: Endres Laura , Jacquin Céline , Traber Jacqueline , Gonzàlez-Lemos Saul , Rodriquez-Rodriquez Laura , Sliwinski Jakub , Kaushal Nikita , Kost Oliver , Stoll Heather M.
Published: March 2022

The interpretation of paleoclimate records from speleothems remains a challenging task due to the individual characteristics of each specimen and cave system. Through recent advances in techniques like confocal microscopy and high-resolution geochemical analysis, fluorescent layers in speleothems have become a significant source of information to enhance paleo-seasonal reconstructions, improve age models and, consequently, constrain rates of past climate changes. In this framework, speleothem fluorescence originates from organic matter produced in the soil above the cave, from ancient organic compounds in the bedrock or from microbial processes within the karst. However, the mechanisms leading to the incorporation of fluorescent banding into calcite as well as the properties of transport, storage and decomposition of organic matter in natural karst systems are still under debate. We present results from a one-year monitoring study of fluorescence properties in drip water, sampled from May 2020 to May 2021 in a quasi-monthly resolution at 3-6 locations within the cave system La Vallina in Northwestern Spain. We have measured absorbance spectra and fluorescence exitation-emission matrices; and compare it to drip water geochemistry, fluorescence of active speleothems at the same site and vegetation type above the cave. Our results indicate high gradients of fluorescent properties in drip waters already on a small spatial scale. In the site where active speleothems show fluorescent banding, a humic-like fluorescent signal prevails in cave waters (AC peak, according to Coble nomenclature), while other sites are more likely to be influenced by microbial activity (B/M peak). Humic-like fluorescence is stronger in drip waters during the autumn season, probably due to the increased input by colloids. Yet, simple relationships between the fluorescence in drip water and colloid-associated trace elements like Cu and Y cannot be confirmed. Further, the difference in drip water fluorescence is small compared to the actual intra-seasonal difference retrieved by confocal microscopy in active stalagmites. Therefore, we find drip water composition unlikely to be solely responsible for seasonal enriched fluorescence incorporation in speleothems and favour conceptual models taking moisture-limitation and adsorption into account.
One model fits all – on the generalizability of pipe deterioration models between utilities
Authors: Daulat Shamsuddin , Rokstad Marius Møller , Bruaset Stian , Tscheikner-Gratl1 Franz
Published: March 2022

For proactive management of water distribution pipe networks, one pre-requisite is to predict either pipe failure probability for risk assessment on a tactical level or life expectancies for budget allocation on a strategic level or preferably both. Machine learning methods are documented to provide promising results for predicting water distribution pipe failures. Still, they rely on a considerable amount of data, which is seldom available with sufficient quality. Especially, small municipalities lack the required amount and quality of data to utilize the benefits of machine learning models. This study aims to train a deterioration model based on random survival forests (RSFs) by using datasets from several utilities in Norway and testing the model’s usability for the individual networks to assess its generalizability. The benefit of using RSFs is twofold: 1) it can model complex relationships between the variables and output, 2) it accounts for right-censored data. The method is tested on pipe failure data from nine different, small to medium-sized water utilities. Furthermore, this work highlights the possibilities and limitations of such a machine learning approach.
A multispectral remote sensing monitoring of the temporal and spatial extent of whiting events in Lake Geneva.
Authors: Many Gaël , Ferrari Michele , Escoffier Nicolas , Perolo Pascal , Herr Isabel , Perga Marie-Elodie
Published: March 2022

Whiting events, i.e., sudden and massive calcite precipitation turning lake waters to a milky turquoise colour, are unpredictable in space and time. This lack of understanding arises from the transitory nature of whiting events and their variable spatial extent, which are not well captured by traditional monitoring. We use a multi-spectral remote sensing approach to reconstruct the occurrence, timing, and spatial extent of whiting events in Lake Geneva from 2013 to 2021. Landsat-8 and Sentinel-2 multispectral sensors were combined and intercalibrated to derive the AreaBGR index and identify whiting events over the studied period. Then, intercalibrated remote sensing was used to estimate spatial extents and temporal occurrences of whiting events in Lake Geneva. Principal Component Analysis (PCA) identified environmental drivers of typical features of whiting events (such as meteorological, Rhône River and lake physical conditions). KNN (K-nearest neighbours) was used to reconstruct the full time-series of whiting events over the last 50 years. Ongoing results show that the combination of multi-spectral sensors is suitable for monitoring whiting events in Lake Geneva, based on the description of their spatial and temporal occurrences.
A Review on Need of Application of Ensemble Techniques for Streamflow Forecasting in India
Authors: Panchal Ayushi , Yadav Dr. S. M. , Yadav Rashmi , Patel Anant
Published: March 2022

Water is the most essential resource, which is naturally available. Poor management of water can cause drought in some areas and also floods in some areas. Flood is one of the most disastrous events which can cause tremendous losses. In India, the techniques which are developed for real time flood forecasting are based on deterministic as well as statistical approach. The quantification of uncertainties is having the primary importance in flood modelling systems. The forecasts are simulated multiple times with slight changes in initial conditions as well as model parameters. This is known as ‘Ensemble forecasting’. The Ensemble Techniques approach minimizes the uncertainties in the forecasting. This approach is used in Numerical Weather Prediction (NWP). The advance techniques like remote sensing, data acquisition and monitoring system, hydrologic modelling have led to progress in the flood forecasting techniques and skills. The ensemble approach has potential for creating and disseminating the probabilistic predictions, extending lead-time as well as quantification of predictability. Due to ensemble techniques, the capability to issue the flood warnings and alerts can be increased. In addition to forecast the flood, the ensemble techniques can be used for the reservoir operation, drought estimation, hydropower as well as water management. Hence, moving towards probabilistic approach from deterministic approach would be much helpful to develop reliable flood forecasting systems.  Ensemble forecasting is the probabilistic approach and has the ability for giving information of probability of occurrence for the extreme events. The ensemble forecasting approach is used successfully in various countries of the world. India also needs the reliable approach for producing the operational forecasts.
Electrical activity of the 2021 Cumbre Vieja eruption
Authors: Vossen Caron E.J. , Cimarelli Corrado , Cigala Valeria , Kueppers Ulrich , Barrancos José , Haarer Isabella , Schmid Markus , Stoiber Wolfgang , D’Auria Luca , Padilla Germán , Hernández Pedro , Pérez Nemesio
Published: March 2022

Volcanic lightning is a common phenomenon observed during explosive eruptions of high magnitude and intensity. Lightning observations in milder explosive eruptions, generally of basaltic composition, are less frequent, arising the question of whether electrification may be a common feature over the whole spectrum of explosive styles and magma compositions.

The 2021 eruption of Cumbre Vieja on the island of La Palma (Canary Islands, Spain) started on 19 September 2021, continuously producing lava flows and tephra of average basanite to tephrite composition during 85 consecutive days, eventually generating a >200 m tall scoria cone (about 1220 m a.s.l.) and a vast compound lava flow field. Lightning was frequently observed in the plume during different phases of the explosive activity. This eruption provided the rare opportunity to monitor variations in the electrical activity on various time scales continuously over several weeks. We measured such electrical activity using a lightning detector operating in the extremely low frequency range with a sample rate of 100 Hz (Vossen et al., 2021), installed about 2 km away from the active vents. The detector was deployed on 11 October 2021 and recorded continuously until the end of the eruption on 13 December 2021, thus providing a unique dataset of its kind.

Lightning activity varied during the eruption with alternating hours-long periods of high intensity continuous lightning production as well as minutes-long isolated episodes with interposed periods of quiet. Stable fair-weather conditions over La Palma recorded by meteorological stations during the whole eruption (exception made for a thunderstorm episode on 26 November 2021), allow a confident attribution of the changeable lightning activity to the explosive activity of the scoria cone. Here, we present volcanic lightning and electrification timeseries as a function of the varying explosive activity as observed through thermal videography and acoustic recordings (Cigala et al., 2022).

 

Vossen, C. E. J., Cimarelli, C., Bennett, A. J., Geisler, A., Gaudin, D., Miki, D., Iguchi, M., and Dingwell, D. B. (2021). Long-term observation of electrical discharges during persistent Vulcanian activity. Earth Planet. Sci. Lett., 570, 117084. https://doi.org/10.1016/j.epsl.2021.117084.
Irrigation mapping using Sentinel-1 and Sentinel-2 data
Authors: Zribi Mehrez , Le page Michel , Jarlan Lionel , Baghdadi Nicolas , Brocca Luca , Modanesi Sara , Dari Jacopo , Quintana Segui Pere , Elwan Ehsan
Published: March 2022

Water resource management is a key issue in climate change conditions, considering the increasing number of drought events, as well as the increase in water use for irrigation in Mediterranean region. In this context, different decision tools have been developed to optimize water use for irrigation. One crucial question for managers is the precise identification of irrigated areas. Remote sensing has shown great potential for irrigation mapping. This study aims to propose an operational approach to map irrigated areas based on the synergy of Sentinel-1 and Sentinel-2 data. An application is proposed at two study sites in Mediterranean region, in Spain and in Italy, with two climatic contexts, semiarid and humid respectively. Several classifiers are proposed to separate irrigated and rainfed areas. They are based on statistical variables from Sentinel-1 and Sentinel-2 time series data at the agricultural field scale, as well as on the contrasted behavior between the field scale and the 5-km surroundings. Support Vector Machine (SVM) classification approach is tested with different options to evaluate the robustness of the proposed methodologies. The optimal number of metrics found is five. The highest accuracy of the classifications, approximately equal to 85%, is based on training dataset with mixed reference fields from the two study sites. In addition, the accuracy is consistent at the two study sites.
How treated wastewater used for irrigation, and sewage sludge used as soil amendment affect CO2 emission from soils 
Authors: Nikodem Antonín , Fér Miroslav , Kodešová Radka , Klement Aleš
Published: March 2022

Sewage sludge from wastewater treatment plants or farm biosolids can be used as a source of organic matter to improve soil quality. Treated wastewater is due to a water scarcity also used for irrigation. These sources contain a large amount of nutrients, which can enhance conditions for plants’ growth, but also can increase a CO2 emission from soils. Despite that these soil amendments can have a significant impact on the CO2 emission from soils, their actual effect on measured values has not been fully revealed. Therefore, the goal of this study was to evaluate the effect of products from the municipal wastewater treatment plant on the CO2 efflux from soils.  Experiment was carried out directly in the wastewater treatment plant, where nine raised beds were installed, which contained soils taken from topsoil of two soil types Arenosol (two beds) and Cambisol (seven beds). Either maize or a mixture of different vegetables (lettuce, carrot and onion) was grown in these beds. Of the seven beds with the Cambisol, one of the beds containing either maize or vegetables was irrigated with tap water and other pair of beds (maize or vegetables) was irrigated with treated wastewater (i.e., WWTP effluent). In another pair of beds (maize or vegetables), composted sludge from WWTP Three beds containing both types of biosolids were irrigated with tap water. Only vegetables were grown in the beds with the Arenosol, which were irrigated with either tap water or treated wastewater. Climatic data, irrigation doses, drainage water volumes, soil water contents and plant growth were monitored during the experiment. The soil CO2 efflux was measured in a steel collar (diameter of 11 cm and height of 7.5 cm), which was placed into the surface of each bed one hour prior to the measurement. The net CO2 efflux (NCER) and the net H2O efflux were measured using the LCi-SD portable photosynthesis system with a Soil Respiration Chamber. While stabilized and composted sewage sludge considerably increased the CO2 emission, the effect of treated wastewater or plant was not confirmed.

 

Acknowledgement: Study was supported by the Ministry of Agriculture of the Czech Republic, project "The fate of selected micropollutants, which occur in treated water and sludge from wastewater treatment plants, in soil" (No. QK21020080) and partly also by the European Structural and Investment Funds, projects NutRisk (No. CZ.02.1.01/0.0/0.0/16_019/0000845). 
Comparison of total atmospheric microplastic deposition on a peri-urban and an agricultural site in the Paris region
Authors: Beaurepaire Max , Dris Rachid , Tassin Bruno , Gasperi Johnny
Published: March 2022

Although the topic of microplastic pollution has been a source of increasing scientific interest since 2004, some environments are less studied and less understood than other. In particular, microplastics in the atmospheric compartment have only been studied for a few years.

Here, the literature on microplastics in the atmospheric compartment is reviewed. Upon studying published articles up to December 2020, two main categories of sampling strategies were distinguished. Articles either indirectly studied the atmospheric compartment through collection of deposited particles, or directly sampled air using vacuum pumping methods. While general sampling strategies remained the same, analysing methods was more variable.

In the following study, total atmospheric fallout was monitored on two sampling sites in the Paris region. In total, three monitoring campaigns were conducted, each lasting 4 to 6 months. Total atmospheric fallout sampling was collected using passive samplers. Each sampler consisted in a 0.3 m² metal funnel held in place in a wooden crate, and connected to a glass bottle. Samples were collected over periods ranging from 3 to 10 days. After collection, samples underwent a treatment process consisting of a density-based separation followed by a Fenton treatment. Samples were then placed on an anodisc filter and characterized using an automated µFTIR mapping analysis with a Nicolet iN10 by Thermo Scientific. Microplastics could be identified down to a size of 25 µm, cutoff point determined by the µFTIR detectors.  Finally, results were analysed using the open access software for Systematic Identification of MicroPlastics in the Environment (siMPle) developed at the Aalborg university, Denmark and the Alfred Wagner Institute in Helgoland, Germany.

Preliminary results from the total atmospheric fallout monitoring campaigns showed orders of magnitudes of a few dozen particles deposited per square meter per day (p/m²/d). Results from samples collected in a peri-urban sampling site showed deposition rates of 14.3 to 47.1 p/m²/d, while results from a rural sampling site showed deposition rates of 4.3 to 18.9 p/m²/d. While a dozen different polymers were identified, the majority of particles were polypropylene, followed by polyethylene and polystyrene. As of yet, results between sites remain to be assessed. The results will also be compared with the frequency and intensity of rain events to assess the effect of precipitations on atmospheric deposition. In particular, several samples were collected during dry spells. The deposition rates on these samples may be compared to the deposition rate during single rain events or longer precipitation periods.   

 
Resolution Dependence of Southern Ocean Mixed-Phase Clouds in ICON
Authors: Possner Anna , Danker Jessica , Ramadoss Veeramanikandan
Published: March 2022

Extratropical low-level mixed-phase clouds are difficult to represent in global climate models and generate substantial uncertainty in global climate projections (Zelinka et al. 2020). In this study we evaluate the simulated properties of Southern Ocean (SO) boundary layer mixed-phase clouds for August 2016 in the ICOsahedral Nonhydrostatic (ICON) model (Zängl et al. 2015). The bulk of the simulations are part of the DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domain (DYAMOND) initiative (Stevens et al. 2020). Within DYAMOND, ICON was run with the German Weather Service (DWD) physics packages at resolutions ranging from the global climate scale to the convection-permitting scale. All simulations are evaluated with respect to their radiative and cloud properties using Clouds and the Earth’s Radiant Energy System (CERES, Su et al. 2015), Moderate Resolution Imaging Spectroradiometer (MODIS), and the raDAR-liDAR (DARDAR) version 2 (Ceccaldi et al. 2013) retrievals.

The analysis shows that previous and current versions of ICON overestimate cloud ice occurrence in low-level clouds across all latitudes in the SO. Furthermore, ICON, like many other global climate models, underestimates the reflectivity of SO boundary layer clouds. We can show that this effect is resolution dependent and largely due to an underestimation in cloud occurrence, rather than optical depth. Additional sensitivity experiments with respect to temporal model resolution and convection scheme assumptions were performed. We find a stronger model sensitivity with respect to spatial versus temporal resolution. Assumptions made within the convection scheme with respect to detrained cloud ice were found to impact the simulated total ice water content, but had a marginal impact on cloud-radiative properties.

In summary, while increases in model resolution increase cloud water content, cloud occurrence and cloud optical depth, considerable radiative biases remain in SO clouds in ICON at the convection-permitting scale. Furthermore, cloud ice forms to readily in state-of-the-art DWD ICON simulations at all spatio-temporal resolutions analysed.
Observations of Energetic Electron Substorm Injection Signatures by Cluster and BepiColumbo During an Earth Flyby
Authors: Grande Manuel , Sanches-Cano Beatriz , Nakamura Rumi , Vainio Rami , Miyoshi Yoshizumi , Dandouras Iannis , Johnson Rosie , Oleynik Philipp , Nakamura Satoko , Perry Chris , Johnson Patrick , Huovelin Juhani , Maguire Sophie , Heyner Daniel
Published: March 2022

Observations of Energetic Electron Substorm Injection Signatures by Cluster and BepiColumbo During an Earth Flyby

We present an analysis of the energetic electron signatures observed by BepiColumbo and Cluster during the Bepi flyby of Earth on 10 April 2020, as well as other spacecraft. After closest approach, the SIXS instrument on Bepi observed two separate substorm injection fronts, while Cluster RAPID/IES also observed a sequence of energetic electron signatures. Bepi and Cluster were in a particularly favourable configuration during this event, with Bepi moving rapidly radially outward near the nightside equatorial plane while the four Cluster spacecraft cut the same region in a north/south direction in a string of pearls configuration. The coincidence of this favourable geometry with the substorm activity is highly fortuitous and appears to show a complicated sequence of spatially and temporally separated injections and drift echoes.
Generative Adversarial Modeling of Tropical Precipitation and the Intertropical Convergence Zone
Authors: Nash Cody , Nadiga Balasubramanya , Sun Xiaoming
Published: March 2022

In this study we evaluate the use of generative adversarial networks (GANs) to model satellite-based estimates of precipitation conditioned on reanalysis temperature, humidity, wind, and surface latent heat flux.  We are interested in the climatology of precipitation and modeling it in terms of atmospheric state variables, in contrast to a weather forecast or precipitation nowcast perspective.  We consider a hierarchy of models in terms of complexity, including simple baselines, generalized linear models, gradient boosted decision trees, pointwise GANs and deep convolutional GANs. To gain further insight into the models we apply methods for analyzing machine learning models, including model explainability, ablation studies, and a diverse set of metrics for pointwise and distributional differences, including information theory based metrics.  We find that generative models significantly outperform baseline models on metrics based on the distribution of predictions, particularly in capturing the extremes of the distributions.  Overall, a deep convolutional model achieves the highest accuracy.  We also find that the relative importance of atmospheric variables and of their interactions vary considerably among the different models considered. 
Inertial waves excited by topography 
Authors: Burmann Fabian , Noir Jerome
Published: March 2022

We bring together two important features of planetary cores: 1) wave propagation in the fluid and 2) topography of the fluid-solid interface. On one hand, inertial waves contribute to the maintenance of quasi geostrophic motions or to the formation of elongated structures in rotating turbulence. On the other hand, topography of the core-mantle boundary has been prososed in various seismological and geodynamical studies and can modify the fluid flow in the core, for example, by altering global fluid modes. Here, we focus on inertial waves excited by topography.

We present results from a combined numerical and experimental investigation of inertial wave motion which is forced by an oscillating topography. To allow comparison with the theory of linear inertial waves, we use a complex topography characterised by a single wavenumber in the spectral domain. Both, the wavenumber and the frequency of the oscillations are varied, allowing us to characterise the transport of kinetic energy at different length scales as well as the interactions of direct and reflected inertial waves. 
Lessons learnt from a field trial of colloidal activated carbon injection to reduce PFAS migration from a contaminated site
Authors: Fagerlund Fritjof , Niarchos Georgios , Ahrens Lutz , Berggren Kleja Dan , Bergman Jonny , Larsson Anna , Leonard Gareth , Forde Jim , Schütz Matilda , Persson Henning
Published: March 2022

Due to their extreme persistence, often combined with high aqueous mobility, per- and polyfluoroalkyl substances (PFAS) are challenging to remediate and remove from the environment. Stabilisation by activated carbon is a method that can potentially stop or at least reduce the migration of PFAS and limit further spreading to the environment from contaminated hot spots. In the StopPFAS project, the use of sorbents to limit PFAS migration in groundwater has been investigated, including in a field trial of colloidal activated carbon (CAC) injection at a PFAS contaminated site in Arboga, Sweden. After CAC injection at the field site, there was an initial reduction in PFAS concentrations by approximately 72% for a sum of 11 PFAS. This indicates significant reduction, but that there were still flow paths where the PFAS transport was not intercepted by CAC. Later however, the PFAS concentrations rebounded to levels equal or higher than before CAC injection. After the rebound concentrations again declined to lower than before CAC injection. The reduction in PFAS concentrations by sorption is related to the amount of CAC that the PFAS come in contact with. A sorptive barrier application is likely to be less effective if the CAC emplacement is uncertain or does not reach all flow paths, if the contaminant transport is dominated by a few preferential flow channels or if the barrier is bypassed due to changes in flow directions. Furthermore, our laboratory experiments indicate that competition with natural organic matter (NOM) does not have a large net effect on the PFAS sorption to CAC on the site. The most reasonable explanation to the post-CAC-injection changes in downstream PFAS concentrations was deemed to be changes in the groundwater flow direction causing bypass or partial bypass of the injected CAC. It was concluded that the distribution of CAC in the subsurface and the extent to which CAC intercepts the PFAS-transporting groundwater are critical to the reduction in PFAS concentrations leaving the contaminated site. The soil characteristics including texture, heterogeneity and existence of preferential flow channels are important factors for the resulting CAC distribution. In a treatment with CAC to limit PFAS migration the goal is to catch as much as possible of the contaminant transport with the injected CAC. Our results show that complex hydrogeological conditions pose a challenge to this goal. For optimal design and placement of a sorptive CAC barrier, it is essential to have a detailed characterization and understanding of soil conditions, groundwater flow directions, including seasonal variations, and flux-zone locations on the local scale of flow through and around the CAC barrier.