bluuebunny/crossref_metadata_2025 huggingface dataset:
Three different glacier surges at a spot: What satellites observe and what not
Authors: Paul Frank , Piermattei Livia , Treichler Désirée , Gilbert Lin , Girod Luc , Kääb Andreas , Libert Ludivine , Nagler Thomas , Strozzi Tazio , Wuite Jan
Published: March 2022

In the Karakoram, dozens of glacier surges occurred in the past two decades, making the region one of the global hotspots. Detailed analyses of dense time series from available optical and radar satellite images revealed a wide range of surge behaviours in this region: from slow advances characterized by slow ice flow over periods longer than a decade to short, pulse-like advances with high velocity over one or two years.

In this study, we present an analysis of three glaciers that are currently surging in the same region of the central Karakoram: North Chongtar, South Chongtar and an unnamed glacier referred to as NN9. A full suite of optical and SAR satellite sensors and digital elevation models (DEMs) are used to (1) obtain comprehensive information about the evolution of the surges between 2000 and 2021 and (2) to compare and evaluate capabilities and limitations of the different satellite sensors for monitoring small glaciers in steep terrain. 

The analysis for (1) reveals a contrasting evolution of advances rates and flow velocities for the three glaciers, while the elevation change pattern is more similar. South Chongtar Glacier showed advance rates of more than 10 km y-1, velocities up to 30 m d-1 and surface elevations raised by 200 m. In comparison, the three times smaller North Chongtar Glacier has a slow and almost-linear increase of advance rates (up to 500 m y-1), flow velocities below 1 m d-1 and elevation increases of up to 100 m. The even smaller glacier NN9 changed from a slow advance to a full surge within a year, reaching advance rates higher than 1 km y-1, but showing the typical surface lowering higher up only recently. It seems that, despite a similar climatic setting, different surge mechanisms are at play in this region and that the surge mechanisms can change in the course of a single surge. 

On topic (2) we found that sensor performance is dependent on glacier characteristics (size, flow velocity, amplitude of changes). In particular velocities derived from Sentinel-1 performed poorly on small, narrow glaciers in steep environment. The comparison of elevation changes revealed that all considered DEMs have a sufficient accuracy to detect the mass transfer during the surges and that elevations from ICESat-2 ATL06 data fit neatly. 
Scalewise Universal Relaxation to Isotropy of Inhomogeneous Atmospheric Boundary Layer Turbulence
Authors: Stiperski Ivana , Katul Gabriel G. , Calaf Marc
Published: March 2022

The turbulent energy cascade is one of the most recognizable characteristics of turbulent flow. Still, representing this tendency of large-scale anisotropic eddies to redistribute their energy content with decreasing scale, a phenomenon referred to as return to isotropy, remains a recalcitrant problem in the physics of turbulence. Atmospheric turbulence is characterised by large scale separation between production and viscous destruction of turbulent kinetic energy making it suitable for exploring such scale-wise redistribution of energy among velocity components.  Moreover, real-world atmospheric turbulence offers an unprecedentedly diverse source of inhomogeneity and large-scale anisotropy (caused by shear, buoyancy, terrain-induced pressure perturbations, closeness to the wall) while maintaining a high Reynolds number state. It may thus be assumed that relaxation through the energy cascade may be dependent on the anisotropy source, thus adding to the ways that atmospheric turbulence differs from canonical turbulent boundary-layers.

Here, we examine the scalewise return to isotropy for an unprecedented dataset of atmospheric turbulence measurements covering flat to mountainous terrain, stratification spanning convective to very stable conditions, surface roughness ranging over several orders of magnitude, various distances from the surface, and Reynolds numbers that far exceed the limits of direct numerical simulations and laboratory experiments.  The results indicate that irrespective of the complexity of the dataset examined, the return-to-isotropy trajectories that start from specific initial anisotropy at large scales show surprising scalewise universality in their trajectories towards isotropy. This novel finding suggests that the effects of boundary conditions, once accounted for in the starting anisotropy of the trajectory in the cascade, cease to be important at much smaller scales. It can therefore be surmised that large-scale anisotropy encodes the relevant information provided by the boundary conditions, adding to the body of evidence that the information on anisotropy is a missing variable in understanding and modelling atmospheric turbulence [1-3].

 

[1]  Stiperski I, and M Calaf. Dependence of near-surface similarity scaling on the anisotropy of atmospheric turbulence. Quarterly Journal of the Royal Meteorological, 144, 641-657, 2017.

[2]  Stiperski I, M Calaf and MW Rotach. Scaling, anisotropy, and complexity in near-surface atmospheric turbulence. Journal of Geophysical Research: Atmospheres, 124, 1428-1448, 2019.

[3] Stiperski I, GG Katul, M Calaf. Universal return to isotropy of inhomogeneous atmospheric boundary layer turbulence. Physical Review Letters, 126 (19), 194501, 2021
Modelling CME rotation during propagation in the heliosphere with EUHFORIA
Authors: Maharana Anwesha , Scolini Camilla , Schmiede Brigitte , Poedts Stefaan
Published: March 2022

Coronal mass ejections (CMEs) are large scale magnetized plasma eruptions from the Sun that propagate to Earth and cause disruptions in space and ground-based technologies. While propagating through the heliosphere, they undergo interaction with other CMEs, as well as structures in the solar wind like high-speed streams, and co-rotating/stream interaction regions. We present a case-study of two Earth-directed interacting CMEs that erupted from the Sun on September 8, 2014, and September 10, 2014, respectively. While the first CME was a side hit, it is the second CME which is the focus of this study. With remote observations of the CME helicity and tilt, the second CME was predicted to be geoeffective. However, a mismatch in the tilt of the second CME was observed close to Earth, pointing to CME rotation during its propagation. Unexpectedly, the ejecta resulted in positive Bz but a geoeffective sheath was developed during the evolution and the interaction in the heliosphere that resulted in a minimum Dst ~ -100nT at Earth. Hence, the geoeffectiveness of the various sub-structures involved in this event was mispredicted. 

It is challenging to capture the complete picture of the CME and solar wind dynamics with in-situ observations taken at sparse localized points in the heliosphere. Therefore, we perform 3D MHD simulations that provide a global picture, making it convenient to probe into the interesting phenomena of this event. With the EUropean Heliosphere FORecasting Information Asset (EUHFORIA), we model the background solar wind in 3D, launch the flux rope CMEs in it and let the CME evolve till Earth. In this work, we aim to reproduce the observed plasma and magnetic field properties, especially the negative Bz of the sheath and the positive Bz of the ejecta at Earth. We address the possible factors and processes responsible for the development of geoeffectiveness from the CME rotation, the interplay of the two CMEs and the heliosphere. 

This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 870405 (EUHFORIA 2.0)
The two faces of the Jovian UV aurorae
Authors: Bonfond Bertrand , Grodent Denis , Palmaerts Benjamin , Gladstone Randy , Badman Sarah , Clarke John , Gérard Jean-Claude , Giles Rohini , Greathouse Thomas , Haewsantati Kamolporn , Hue Vincent , Kammer Joshua , Nichols Jonathan , Sicorello Guillaume , Wannawichian Suwicha , Yao Zhonghua
Published: March 2022

Being mostly connected via closed magnetic field lines, the aurorae at the two poles display two broadly similar signatures of the same magnetospheric processes. However, differences are sometimes observed, indicative of asymmetries either in the polar regions (e.g. different solar illumination, magnetic anomalies, etc.) or in the magnetosphere (e.g. twisting of the magnetotail), thus showing two complementary sides of the magnetosphere-ionosphere coupling.

Whatever the planet, seeing the aurorae on both poles at the same time is challenging. Either both polar regions can be seen at once, but then only from the side, with poor spatial coverage (especially close and beyond the limb), or we need (at least) two observatories. Here we use the latter option to observe the two faces of the UV aurorae on Jupiter. In the last years, several Hubble Space Telescope observations with the Space Telescope Imaging Spectrograph (STIS) have been planned during close-up perijove observations of the poles with the UV spectrograph (UVS) on board the Juno spacecraft. The aurorae at Jupiter can be divided into three main components, with the Main Emissions, a quasi-continuous, but sometimes irregular, ribbon of auroral emissions, delimitating the outer emissions outside of it and the polar emissions inside of it. We compare the global morphology and the relative power emitted by the different auroral features in these three regions. Former studies also indicated that synchronized quasi-periodic flares could be observed in both hemispheres and we will look after similar events in this new dataset. Finally, even if the observations are delayed by approximately one hour, we can still compare the mean emitted power before (north) and after (south) each Juno perijove to look for a global trend.
Opportunities and drivers for green hydrogen production from renewable energy: Constructing of a causal loop diagram from stakeholders perspective in Iceland.
Authors: Perruchoud Robin , Vögeli Guillaume , Finger David Christian
Published: March 2022

Green hydrogen produced through electrolysis using renewable energy has the potential to decarbonize many sectors by replacing fossil fuels. Although production is currently marginal, green hydrogen projects are initiated and assessed all around the globe, ranging from small energy systems to large-scale production units. Previous studies have identified a wide range of key stakeholders that influence the diffusion of green hydrogen technologies. However, an understanding of the overall complexity of the emerging hydrogen sector regarding techno-economic, social, and environmental aspects is needed. The main objective of this study is to provide a depiction of an emerging sustainable technology sector by integrating various stakeholders’ perspectives. Based on this mapping key mechanisms that foster or hinder the production of green hydrogen will be identified. To perform our study, we chose a green hydrogen production project at the Hellisheiði geothermal power plant (Iceland) to construct a causal loop diagram (CLD) of the Icelandic green hydrogen production sector. Seven semi-structured interviews and one e-mail interview were conducted with relevant stakeholders. The National Innovation System was taken as a conceptual model in order to encourage the participants to answer in a systemic manner. Variables and causal links were then extracted from the interview transcripts using a coding process adapted from the literature. An overall CLD was constructed, showing the dynamic complexity of the system. The results show that mobility and export are the main sources for enhanced demand. Since most power companies in Iceland are state owned, green hydrogen supply comes mainly from energy companies, and strongly depends on political support. The importance of civil society, especially concerning the topics of nature protection and climate awareness, is also depicted. Additionally, a range of social, technical, and economical factors are identified, as well as their impact on the system’s behavior. The diagram allows for comprehension of stakeholders’ expectations and concerns with their potential consequences on the diffusion on green hydrogen technologies. The use of system dynamics and causal loop modelling provides a comprehensive view on the problem and helps to address issues that could be overlooked without it. Some of these causal chains could potentially lead to policy failure if not addressed early enough. The findings can be used to enhance cooperation between stakeholders and guide decision-making processes.
BAR Talks: a YHS-Italy webinar series to bring hydrological researchers and practitioners close together 
Authors: Meggiorin Mara , Cristiano Elena , Siena Martina , Peli Marco , Zuecco Giulia
Published: March 2022

Hydrological sciences can contribute to society in numerous impactful ways: thus, it is crucial that we make an effort to enhance the opportunities for collaboration between academia and society, such as industry and territorial authorities. With the support of the Italian Hydrological Society (‘Società Idrologica Italiana'), in 2021, the Italian Young Hydrologic Society (YHS-Italy) organized a series of webinars to reduce the gap between academic researchers and practitioners, belonging to both private and public sectors.

The webinar ‘Beyond Academic Research Talks’ (BAR Talks) hosted a total of 24 guests during five online public meetings discussing three overarching topics: i) the professional careers of Italian researchers, ii) the research in the private sector, particularly at consulting and manufacturing firms of any size, iii) the hydrological and hydrogeological research in the public sector.

The goal was to document heterogeneous experiences and promote a discussion on potential practical applications of academic research. The meetings also served as an opportunity to understand similarities and differences between the role of a hydrological researcher across different institutions. All webinars have been organized online with live sessions, where the audience could interact with the speakers and ask questions. Each meeting was also recorded and made available on YouTube for asynchronous attendances (https://www.youtube.com/channel/UCjDrMpQvRQrp3lxtZTr7Trg).

The initiative has been positively welcomed, particularly by young researchers, and many new interesting topics have been raised. The BAR Talks presented a comprehensive selection of professional paths available to researchers interested in working outside academia, and looking for a more immediate impact on society. The guests talked about the challenges of doing hydrological innovation and research outside academia, and highlighted some of the skills that become particularly handy in the private sector (e.g., open-source software, programming languages, digital water, project management, soft skills). 

Finally, one issue that came out strongly from the BAR Talks series was the need, especially for the private sector, to close the gap between academic research and its real-world applications in order to improve the positive impact that academic research can have on society. Indeed, real-world applications often encounter constraining challenges that are sometimes missing from academic research. Overall, we observed that there is a widespread desire for a closer collaboration between hydrological academic researchers and practitioners, which may take the form of joint research projects aimed at producing impactful knowledge. 
The anomalous North Atlantic region
Authors: Thybo Hans , Artemieva Irina
Published: March 2022

The whole North Atlantic region has highly anomalous topography and bathymetry. Observations show evidence for anomalously shallow bathymetry in the ocean as well as recent rapid topographic change with onshore uplift close to the Atlantic coast and simultaneous subsidence of basins on the continental shelves, most likely throughout the Mesozoic. We present a geophysical interpretation of the whole region with emphasis on data relevant for assessing hypsometric change

Most of the North Atlantic Ocean has anomalously shallow bathymetry by up-to 4 km compared to other oceans. Bathymetry is elevated by up-to 2 km and follows the square-root-of-age model, except for the region between Greenland Iceland Faroe Ridge (GIF) and the Jan Mayen Fracture Zone as well as in the Labrador Sea to Baffin Bay. Heat flow follows with large scatter the square-root-of-age model in parts of the ocean and is anomalously low on the Reykjanes and Mohns spreading ridges. Near-zero free-air gravity anomalies indicate that the oceanic areas are generally in isostatic equilibrium except along the mid-oceanic ridges, whereas anomalously low Bouguer anomalies in the oceanic areas indicate low density in the uppermost mantle. Anomalously thick crust is observed along GIF and extends into the Davies Strait. There is no correlation between bathymetry and heat flow, which indicates that the anomalous bathymetry mainly is caused by compositional variation and isostatic compensation of low density continental lithosphere within the oceanic regions. The location of major oceanic fracture zones and continental fragments appears to be controlled by onshore structures.

The onshore circum-Atlantic areas show rapid uplift close to the coast with rates of up-to 3 cm/yr. This is surprisingly mainly associated with strong positive free-air gravity anomalies, which would predict isostatic subsidence. Some parts of the high topography, however, appear supported by low-density anomalies below the seismic Moho. It is enigmatic that the presumed Archaean-Proterozoic continental Barents Sea region is submerged and includes deep sedimentary basins.
Toarcian marine vertebrate preservation in the Grands Causses Basin (France)
Authors: Bomou Brahimsamba , Suan Guillaume , Schlögl Jan , Grosjean Anne-Sabine , Suchéras-Marx Baptiste , Adatte Thierry , Spangenberg Jorge , Fouché Stéphane , Zacaï Axelle , Gibert Corentin , Brazier Jean-Michel , Perrier Vincent , Vincent Peggy , Janneau Kévin , Martin Jeremy E.
Published: March 2022

Several episodes of strong climate change and environmental perturbation marked the Early Jurassic, and culminated during the Toarcian Oceanic Anoxic Event (T-OAE), characterised by widespread deposition of organic-rich shales. Exceptionally preserved fossils of marine vertebrates and invertebrates have been discovered in the Toarcian shales of NW Europe, but the potential links between the occurrences of these exceptionally preserved fossils and the T-OAE remain poorly investigated. Paleontological excavations realized in Toarcian strata near Lodève (Grands Causses Basin, southern France) have yielded several specimens of marine vertebrates and abundant invertebrate fauna. We have developed a multiproxy approach (ammonite biostratigraphy, X-ray diffraction-bulk mineralogy, Rock-Eval pyrolysis, stable isotopes, trace element, phosphorus and mercury contents) to place these findings in a well-defined temporal and paleoenvironmental context, and hence constrain the factors that led to their extraordinary preservation. The Jenkyns Event interval, unambiguously identified at the base of the Toarcian organic-rich shales by a 5‰ negative carbon isotope excursion, records higher mercury fluxes, which suggest a causal link with intense volcanic activity of the Karoo–Ferrar large igneous province. This interval is very condensed and unfossiliferous, and might have been deposited under abnormally low-salinity conditions. Our data exhibit that the deposition of the vertebrate-yielding horizons post-dated the T-OAE by several hundreds of ka, and took place during a prolonged period of widespread oxygen-deficiency and high carbon burial. Our results indicate that the unusual richness in vertebrates of the studied site can be explained by a combination of regional factors such as warming-induced, prolonged seafloor anoxia, and more local factors, such as extreme condensation owing to reduced dilution by carbonate and detrital input.
Forensic disaster analysis of the 2021 summer floods in Western Germany, Belgium and the Netherlands – Findings from the PERC study 
Authors: Rözer Viktor , Ulrich Jonathan , Szönyi Michael , Ianni Francisco , Laurien Finn , Deubelli Teresa , MacClune Karen , Norton Rachel
Published: March 2022

Severe flooding in Western Germany, Belgium and the Netherlands in July 2021, particularly along the rivers Erft, Ahr and Meuse rivers has led to more than 240 causalities and an estimated damage of 29,2 billion EUR in Germany alone. The high human and economic costs of the event brought systemic problems in the flood risk management system to light and raised questions about the limits of disaster risk management and climate change adaptation. Using a forensic disaster analysis approach, the Post Event Review Capability (PERC), we systematically analyse the strengths and weaknesses of the flood risk management systems in the affected regions, the emergency response and recovery to draw lessons for future disaster risk management and climate change adaptation strategies. For that, PERC synthesizes existing information about the event from the hydro-meteorological characteristics of the physical impact and combines it with qualitative interviews with first responders, flood risk managers and other directly affected stakeholders. We will present key findings from the PERC study on the 2021 floods including the main drivers behind the high casualties and potential shortcomings in the emergency response and recovery as well as recommendations and opportunities for improvement.
Tackling the global change challenges to water security in Tajikistan, the water tower of Central Asia
Authors: Singh Shaktiman , Bhardwaj Anshuman , Sam Lydia , Haro Monteagudo David
Published: March 2022

Tajikistan occupies only 11% of the territory of Central Asia. However, more than 65% of the region’s water resources are formed in the mountainous areas of this country. Changing water availability in mountain regions has a strong impact on water-dependent economic sectors such as energy and agriculture. Anthropogenic climate change is projected to bring about considerable changes to both the timing and volume of water in the long term through rising temperatures, increased snow and glacier melt and a more variable rainfall regime. However, there is limited understanding of what the impact on Tajikistan’s water resources will be, associated with uncertainty around the climate projections and the rate of depletion of the region’s glaciers. In Tajikistan, two-thirds of agricultural production is irrigated, but many farmers still must make a living from rain-fed land, which is even more vulnerable to drought and climate change. In addition to climate change impacts, the potential for conflict in the region is exacerbated by the current high population growth rate of between 2.5% and 3.4% per year. As living standards improve and demand resources increase, pressures on scarce water resources heighten.

Water resources management in Tajikistan is in a state of transition from a centralized administrative approach that existed for more than 30 years to a more integrated river basin approach, as proposed under the current sector reforms. While the current reforms are an essential move towards Integrated Water Resources Management (IWRM), there is still much to be done in the development and implementation of such a strategy. Some of the main issues in this regard is the absence of reliable information on water resources and the need to update old monitoring systems to better understand the behaviour of the water resources systems in the country.

This research focuses on the Zarafshan River, where efforts to implement IWRM started a few years ago, and it is an example of an application for the development of IWRM in other basins in the country. We will present the work carried out to better understand the hydrological balance in the basin incorporating snow and ice melt dynamics by combining the SWAT model with satellite images of daily snow cover.
An overview of modeled dynamic histories of rocky planets
Authors: Coltice Nicolas
Published: March 2022

Every planet is singular, with scars and bumps at their surface. One planet, one history. But the physics at play is common to them, connecting planetary bodies together. Tectonics is a common theme of what we can observe on planets of the solar system, and a central question for explanets. More than 20 years of geodynamic modelling has resulted in  identifying a diversity of tectonic regimes for mantle convection, from very active, like heat-pipe (Monnereau and Dubuffet, 2002 among others) and squishy lid (Lourenço et al., 2020) to almost inert, like stagnant lid (Schmeling and Jacoby, 1982). Tectonics is an emergent property deriving from the intimate structure and composition of a planet. It is also a fundamental piece shaping the surface environment. This presentation will attempt to give an overview of tectonic regimes of planets and propose typical evolutional scenari, connecting structural and compositional histories from the depth to the surface.

 

References

Lourenço, D. L., Rozel, A. B., Ballmer, M. D., & Tackley, P. J. (2020). Plutonic‐squishy lid: A new global tectonic regime generated by intrusive magmatism on earth‐like planets. Geochemistry, Geophysics, Geosystems, 21, e2019GC008756.

Monnereau, M., & Dubuffet, F. (2002). Is Io's mantle really molten?. Icarus, 158, 450-459.

Schmeling, H., & Jacoby, W. R. (1982). On modelling the lithosphere in mantle convection with non-linear rheology. Journal of Geophysics, 50, 89-100.
Multi-seismic imaging: Development of geological and geophysical models of the subsurface in the Iberian Pyrite Belt (SW-Iberia) 
Authors: Carbonell Ramon , Handoyo Handoyo , Martinez Yesenia , Marti David , Alcalde Juan , Ruiz Mario , Ayarza puy , Tornos Fernando
Published: March 2022

Control and natural source seismic reflection records were acquired in the early fall in 2018 in the Sotiel-Elvira mining prospect, as part of the SIT4ME project (funded by EIT RawMaterials). Over 700 seismic digital instruments were deployed in a pseudo-3D grid to register these seismic signals in order to image and characterize the subsurface of the study area. The 2- and 3-component instruments used recorded wide azimuth and relatively long offset data. A 32 Tn Vibroseis truck was used in 900 vibration points to complete the controlled source component of the experiment. The array of receivers (deployed within a grid of 10x10m) recorded P- and S- waves and allowed to develop seismic velocity models derived from first arrival travel time tomography and multichannel analysis of surface waves (MASW). Results are further constrained by density measurements of rock samples and surface geology. The integrated information places structural constrains in the subsurface and allows us to depict areas where higher than average P and S wave velocities, characteristic of massive sulphides, might point out to the existence of new or better delimited deposits within the Iberian Pyrite Belt (SW- Iberia). The area is under assessment for potential future exploitation. This experiment further demonstrates the potential of non-invasive and relatively inexpensive seismic techniques to address high-resolution imaging of mineralized areas.
Susceptibility of microseismic triggering to small sinusoidal stress perturbations at the laboratory scale 
Authors: Colledge Martin , Chanard Kristel , Aubry Jérôme , Pétrélis François , Duverger Clara , Bollinger Laurent , Schubnel Alexandre
Published: March 2022

Small transient stress perturbations are prone to trigger (micro)seismicity. In the Earth's crust, these transient stress changes can be caused by various sources : passing of seismic waves, forcing by tides, hydrological load, and other seasonal climatic loads. A better understanding of the dynamic of earthquake triggering by transient stress perturbations is essential in order to improve our understanding of earthquake physics and our consideration of seismic hazard.

Here, we study an experimental fault system, which mimics the natural seismic cycle, that is to say periodic stress perturbations (of variable amplitude and frequency) superimposed to a far field loading, at crustal pressure conditions. The experimental system is instrumented so that microseismicity — in the form of acoustic emissions (AE) — deformations, and stresses, are continuously recorded during the experiments, in order to study the response of a system producing microseismicity as a function of loading rate, amplitude and frequency of a periodic stress perturbation. 

In practice, confinement pressure oscillation experiments are undertaken on Fontainebleau sandstone gouge-filled artificial faults undergoing axial loading steps with mean slip speeds ranging from 1.9 μm/s to 1.4e-2 μm/s. The amplitude and period of the oscillations range from 0.1 MPa to 2.5 MPa and from 20s to 500s respectively between experiments. In each experiment, at least several hundreds of AEs are detected at each loading rate step. 

A susceptibility of the system’s AE response to confinement pressure amplitude is derived. Predictions of a Coulomb stress failure model criterion describing the ratio of constant loading and oscillation-induced strain rates do not match the observed AE distributions. Susceptibility exhibits a linear relation between confinement pressure amplitude and the acoustic emission modulation amplitude, observations with which recent higher frequency experimental results on dynamic triggering agree. 

Our experiments may help further our understanding of the influence of low inertia stress phenomena on the distribution of seismicity, such as observations of dynamic triggering and seismicity modulation by solid earth tides or seasonal loadings.
A Critical Research Gap Study of Sinkhole Hazard Assessments
Authors: Soltanpour Hedieh , Serrhini Kamal , Serrano Jose , Noury Gildas
Published: March 2022

Karst landscapes are perceived as sensible environments due to soluble rocks (limestone, marble, dolomite, etc.) being the predominant features. The dissolution process in karstic structures poses serious multiple hazards to the communities on which they are built. Sinkholes and ground subsidence are the main geological hazards from these areas causing damage to lives and livelihoods. Meteorological events such as heavy rainfall leading to flooding play an important aggravating factor for these areas which often can collide with the special geological situation resulting in a cascade of hazards (flooding and sinkhole collapse). Consequently, such multi-hazard-forming environments like karst regions present a need to better understand the complex interrelationship of water in the form of flooding and underground cavity collapses. Yet, till the present, our approaches to these hazardous events have been often fragmented and inadequate. Moreover, with climate change having a significant impact on Earth, a change in hydrological processes followed by increasing dissolution of limestone, which may lead to more flooding and sinkhole occurrences, can be predicted in the immediate future. Therefore, research on interrelated hazards will be imperative in order to set priorities for complex natural events. While numerous research works have made attempts to study sinkholes and their contributing factors, to date if not any, few studies have perceived and assessed flooding and sinkhole as a multi-hazard event. Since globally, a shift from single to multi-hazard assessment is being encouraged by international risk communities, the present study is to provide new insight towards flooding and sinkholes assessment emphasising multi-hazard approaches. This critical review aims at understanding the current state of sinkhole-related researches, reviewing grey- and peer-review literature. Afterwards, the studies are classified into seven research themes (Morphology, Flood impacts on karst, Monitoring and prediction, Hazard & risk assessment, Multi-hazard-mapping modelling, Mitigation measure, and Others), demonstrating the more favourite research directions and research gap in the field of sinkhole hazard assessment. The results highlight the importance of the integrated multi-hazard assessment in the areas affected by both flooding and karst hazards and show that so far sinkhole risk assessment (70 articles – 35%) followed by sinkhole morphology (63 articles – 31,5%) have been the most popular research subject within the discipline. This research aids future research to bridge the existing gap towards improving mitigation planning and helping policy and decision-makers in their inclusion of multi-hazard interactions in municipal policies and approaches.
A case study of a rainwater harvesting system for the irrigation of green areas within an urban reconversion project 
Authors: Cauteruccio Arianna , Lanza Luca Giovanni
Published: March 2022

RainWater Harvesting (RWH) and the use of the collected rainwater for the irrigation of urban green areas allow saving potable water resources with respect to a traditional supply from the urban water distribution system. The potential for RWH and reuse depends on the urban surfaces made available for rainwater collection, the associated runoff coefficient and the statistics about the frequency and intensity of rainfall events in the region (the rainfall climatology), compared to the irrigation demand.

In this work we present a case study of a RWH system in course of realization within a reconversion project of a former military area, located in Genova (Italy). The project provides for the rainwater, suitably treated if necessary, to be collected and used for irrigation in the park. Three rainwater collection scenarios (from ground surfaces, sheet metal roof and brick roof) are investigated also by varying the size of the storage tank from 30 to 480 cubic meters. The daily rainfall data as observed in the period 1833-2008 in Genova are used.

We implement a behavioural model to simulate the operation of the RWH system in different conditions. The model is updated with a suitable algorithm for the optimization of the irrigation system in case of significant precipitation events and in the following days. The algorithm accounts for the actual soil water availability for the vegetation and its decay with time, considering the soil type and vegetation.

As the performance indicators for the RWH system, two temporal reliability indexes (fraction of time when storage is not empty and when the demand is fully met) and two volumetric reliability indexes (efficiency and overflow ratios) are calculated per each scenario, upon varying the size of the tank. Finally, the detention time is calculated to assess the water quality deterioration while stored in the tank. The optimal sizing of the storage tank and the mean annual potable water saved are calculated for the three examined rainwater collection scenarios and compared.

The results of the present case study can be applied to a larger scenario by contributing to the cost reduction for irrigation of green urban areas, the street washing and the toilet flushing that do not require using precious potable water.
Automatic classification of peaks in gamma radiation measurements from the Eastern North Atlantic (ENA-ARM) station in Graciosa island (Azores)
Authors: Barbosa Susana , Matos José , Azevedo Eduardo
Published: March 2022

The automatic classification of peaks in gamma radiation time series is relevant for both scientific and practical applications. From the practical perspective, the classification of  peaks is fundamental for  early-warning systems for radiation protection and detection of radioactive material. From the scientific point of view, peaks in gamma radiation are often driven by precipitation  and consequent  scavenging of airborne radon progeny radionuclides to the ground (mainly Pb-214 and Bi-214). Thus measurements of gamma radiation at the earth's surface have the potential to provide information on micro-physical processes occurring high above in the clouds, as the dominant source of radon progeny is thought to be associated with in-cloud processes – nucleation scavenging and interstitial aerosol collection by cloud or rain droplets. 

The present study addresses the classification of peaks in high-resolution (1-minute) gamma radiation time series from the GRM (Gamma Radiation Monitoring) campaign, which is being carried out since 2015 at the Eastern North Atlantic (ENA) station of the ARM (Atmospheric Radiation Measurements) programme. In addition to the gamma time series, precipitation information from laser disdrometer measurements is considered, including rain rate, liquid water content, median drop diameter and droplet concentration. Diverse machine learning algorithms are examined with the goal to identify and classify gamma peaks driven by precipitation events, and further examine the association between precipitation characteristics and the resulting gamma radiation peak on the ground.

 
Uncharacteristically Slow Discharge Process Observed Preceding Lightning Initiation
Authors: Sterpka Christopher , Dwyer Joseph , Liu Ningyu , Demers Nicholas , Hare Brian , Scholten Olaf
Published: March 2022

In continuation of the study reported last year, we report additional results from imaging lightning initiation via interferometric beamforming of data collected by the Dutch LOw Frequency ARray (LOFAR).  Significant improvements have been incorporated into the analysis, including: more accurate antenna characterization, improvements to location accuracy, and the inclusion of a polarization model [Scholten, O., et al., PRD DD12993].  This project complements and enhances the previous work of the LOFAR lightning group of Groningen [Hare, B.M., et al., Nature 568, 360363 (2019)] and [Scholten, O., et al., ESSOAr 10503153] and elucidates regions in which there are a high number of sources within a short duration of time.  Interferometric beamforming techniques enhance both spatial and temporal resolution of lightning sources and as a result, locates and images the first non-impulsive sources in lightning flashes.  These sources are believed to be caused by a streamer-cascade-like initiation event which leads to the formation of the first leader.  Previously observed initiation events start from essentially background and within tens of microseconds ramp up a few orders of magnitude before the first impulsive sources connected with lightning leaders are observed.  The new techniques build upon those previously reported [Sterpka, C., et al., Geophysical Research Letters 48 (2021)] and [Sterpka, C., et al., EGU General Assembly EGU21-13711 (2021)], uncovering new detail in the lightning initiation region and characterization of additional flashes.  This new data includes a slow-propagating initiation discharge, starting 60 ms before the formation of the corresponding lightning leader.  The discharge is within 50 m of the initiation of the lightning leader and propagation speed of this discharge is about 700 ± 30  m/s, comparable to the ion drift speed.  This discharge continues for 30 ms before ceasing, and is likely a failed initiation attempt.
Solving the Physical Hierarchy of Nonlinear Water Wave Equations via a Nearby Lax Integrable Hierarchy with Hamiltonian Perturbations 
Authors: Osborne Alfred
Published: March 2022

The goal of this talk is the study of the non-integrable, physical hierarchy of equations in 2+1 dimensions: Nonlinear Schroedinger, Dysthe, Trulsen-Dysthe and Zakharov. These equations describe, with increasing order, the dynamics of water waves in two dimensions. I demonstrate a procedure to determine a nearby hierarchy of these equations, which is Lax Integrable and the Lax pairs and the Its-Matveev formulae are given. I am then able to show that the solutions of each of these equations can be reduced to a quasiperiodic Fourier series with coherent structure basis functions. These include Stokes waves, envelope solitons and breather packets. In order to return to the original hierarchy of the Nonlinear Schroedinger, Dysthe, Trulsen-Dysthe and Zakharov equations I make a Hamiltonian perturbation of the Lax integrable hierarchy. I then apply a theorem of Kuksin, and a further theorem of Baker and Mumford, to write the algebraic geometric solutions. These steps provide me with an approach for the hyperfast numerical integration of these equations for physics and engineering purposes, and for the analysis of recorded data in one and two dimensions through a procedure I refer to as nonlinear Fourier analysis.
Nature vs. Nurture: Understanding the survival of Archean cratons
Authors: Bedle Heather , Cooper Catherine , Frost Carol
Published: March 2022

In a geodynamic, geological and geophysical review of global Archean cratons, we find that the survival of Archean cratons depends on the initial conditions of their formation, as well as the tectonic processes to which they were exposed.  In a sense, we must consider both their nature and how they were nurtured.  In a review of existing literature and models, we use stability regime diagrams to understand the factors that contribute to the intrinsic strength of a craton: buoyancy, viscosity, and relative integrated yield strength. We find that cratons formed in the Archean when thermal conditions enhanced extraction of large melt fractions and early cratonization promoted the formation of stable Archean cratonic lithosphere.  In terms of the cratons' nurturing, processes that may have modified and weaken cratonic lithosphere include subduction and slab rollback, rifting, and mantle plumes, as these processes introduced materials and conditions that warmed and metasomatized the lithosphere.  Examining four Archean cratons that are more stable, and four that are categorized as modified or destroyed, we note that continental lithosphere that was cratonized prior to the end of the Archean has more potential to survive deformation during the last 500 My. Although, the survivability of these cratons is highly dependent on their unique positions relative to larger scale tectonic processes, such as subduction.   We also observe that once an Archean craton begins to undergo even a small amount of modification, it is more likely to continue to be modified, as it loses the preservation advantage that it had upon birth.
Simulating water flow over a rolling bed of non-cohesive materials by using a Hydromorphodynamic model.
Authors: Alhusban Zaid , Valyrakis Manousos , Farhadi Hamed
Published: March 2022

In the process of sediment exchange from one region of the water column to another, morphological development occurs, as does the transmission of varying sediment concentrations and flow momentum along the stream. Herein, a one-dimensional hydro-morphodynamic model is proposed for simulating water flow over a rolling bed of non-cohesive materials to understand better how water flows. Flow hydrodynamics, sediment movement, and bed growth are all considered in this simulation. The governing equations were solved using first-order accurate Harten Lax-van Leer solvers, and the fluxes at cell sides were determined using a finite volume technique based on a structured rectangular mesh. Adding geometry and bed topography to the equations in both the x and y axes may be used to convert a onedimensional model to a two-dimensional model, which is a common approach to transforming one-dimensional models into two-dimensional models. Experimental measurements are also utilized to test and assess the integrated model.
Simulating traits adaptation of trees in refugia 
Authors: Gloy Josias , Kruse Stefan , Herzschuh Ulrike
Published: March 2022

Cryptic refugia enable tree species to survive outside their current range in an area occupied during a previous glacial/interglacial period. Once the climatic conditions are more favorable the populations can expand from these refugia. This can impact the resulting tree composition as it can enable species to dominate that are computationally weaker. The smaller population size of a cryptic refugium, the isolation and adaptation to unfavorable conditions can however also lead to the loss in genetic diversity and weaker populations.

One type current populations that might finds its origin in those refugia are the larches of Eastern Siberia that are dominating vast areas. While it is known and apparent from observation that once established they present a currently stable ecosystem it is now known what factors lead to their establishment in contrast to Northern America and Europe where other conifers dominate the landscapes.

We are using an individual-based model that includes trait adaptation and will be modified to allow for inbreeding depression effects. This model will be used to simulate the refugia and the connections between them during the glacial to assess the fitness and genetic diversity that long isolation can cause. Furthermore we are going to perform breakout simulations to simulate the migration into the area in the interglacial period.

This results could give insights into the adaptations and genetic diversity in refugia and how these impact the colonization and untimely shape the ecosystem. This knowledge could be used to make stronger predictions about future developments and the possibility of regeneration of the ecosystem should it be further hanged by climate change.
SO2  measurements in volcanic emissions at the Kuril islands by DOAS method
Authors: Bruchkouski Ilya , Litvinovich Hleb , Guliaeva Sviatlana
Published: March 2022

One way to predict eruptions is to analyze measurements of the gas composition of volcanic emissions. Depending on the geological features of the rock and the proximity of magma to the earth's surface, the ratio of the concentrations of volcanic gases in emissions (SO2, BrO, etc.) may change. For instance, an increase in SO2 content in emissions may indicate the proximity of magma to the surface.

The main problem of measuring the gas composition of volcanic emissions is the relatively high health risk for the researcher, due to the high content of air pollution near the research object. In this regard, portable instruments that allow remote measurements of the gas composition of volcanic emissions are relevant.

To solve this problem, the authors have developed a portable instrument DEVI (Doas Expedition Volcanic Instrument), which makes it possible to retrieve the slant column of gases in volcanic emissions by the DOAS method. DEVI's main optical module is a spectrometer, designed for the concave diffraction grating (R = 60 mm, 2581 lines / mm) and Toshiba TCD1304DG detector. Optimization of the optical scheme parameters has been carried out aiming to minimize the width of the instrumental function for the spectral range 280-340 nm and the entrance slit 50 × 50 μm.

The handmade instrument DEVI was applied in an expedition to the Kuril Islands during the period 31.07-13.08.2021, aiming to obtain data about the gas composition of volcanic emissions. The paper will present the results of processing the spectra of the celestial sphere near the volcanoes of the Kuril Islands in order to retrieve SO2 and BrO slant columns by DOAS method. In addition, the preliminary mathematical processing of raw spectra will be discussed in order to obtain correct data for the slant columns of volcanic trace gases.