bluuebunny/crossref_metadata_2025 huggingface dataset:
Flood risk assessment for Ecuador 
Authors: Mena-Benavides Melisa , Urrutia Manuel , Scheffczyk Konstantin , Valdiviezo-Ajila Angel A. , Mendoza Jhoyzett , Diaz Gissela , Riembauer Guido , Walz Yvonne
Published: March 2021

Understanding disaster risk is the first priority for action of the Sendai Framework for Disaster Risk Reduction (SFDRR) and is the essential information needed to guide disaster governance and achieve disaster risk reduction. Flooding is a natural hazard that causes the highest number of affected people due to disasters. In Ecuador from 1970 to 2019 flooding caused the highest amount of loss and damage to housing, and from 2016 to 2019 there were 1263 flood events reported. However, the differentiated impacts in flood exposed areas and what can be done to reduce risk and its impacts are still not well understood. In this research, we explored the different dimensions of flood risk, namely hazard, exposure, and vulnerability, and investigated the drivers of risk in different ecological regions of Ecuador. The assessment was conducted at the parish level, the smallest administrative scale, for three selected provinces of Bolivar, Los Ríos, and Napo, representing not only the country’s three main ecological regions but also commonly affected territories due to flooding. Using an automated flood detection procedure based on Sentinel-1 synthetic aperture radar data, flood hazard information was derived from flood frequency and flood depth for the years 2017, 2018, and 2019. The drivers of exposure and vulnerability were derived from scientific literature and further evaluated and complemented during a participatory workshop with over 50 local experts from the different regions. Centered on this exercise, an indicator library was created to inform the data selection from various sources and provides the basis for deriving a spatially explicit flood risk assessment using an indicator-based approach. Impact data are available to validate the risk assessment at the parish level and with this reveal key drivers of flood risk in different ecological regions of Ecuador. This information will provide the basis to derive targeted measures for disaster risk reduction.
Remotely-sensed time series of rapid terrace formation in the Laguna del Viedma valley (Patagonia)
Authors: Thorndycraft Varyl
Published: March 2021

The Patagonian Andes were subject to a range of geophysical drivers of landscape incision during the Last Glacial Interglacial Transition and Early Holocene, including tectonic and isostatic uplift, and base level fall triggered by rapid lake drainage events. Deciphering the drivers of river system response during this period is complex, and magnitudes and timescales of landscape change are poorly constrained. Herein, a remotely sensed time series of modern lake elevation change and terrace development is investigated for the Laguna del Viedma valley (Argentina) as a modern analogue of Late Quaternary landscape evolution. The aim of the research was to constrain the timing of terrace formation following lake-level fall of the Laguna del Viedma over a ~35 year period from 1985-2019. The objectives were to: 1) use satellite imagery from the period 1985-2019 to document landform, glacier and lake changes in the study area; 2) use remotely sensed imagery to map the landforms of the Laguna del Viedma valley; and 3) analyse terrace elevations using GIS. In total 7 terrace surfaces were distinguished by remotely sensed geomorphological mapping. The highest, and vegetated, T1 terrace surface (+75 m) was likely formed at the end of the last Holocene neoglacial advance. Viedma glacier recession at this time caused the abandonment of an ice-lateral spillway and allowed a subglacial drainage pathway leading to less stable lake level elevations and terrace formation. Whether the abandonment of T1 was associated with the 4 ka or 0.15 ka neoglacial termination constrains ~45 m of incision, at a rate of 0.01-0.33 m/yr, down to the T3 floodplain level by 1985. There then followed ~20 m of incision to the T4 level, which must have occurred by 2006, constraining a minimum rate of incision of 0.95 m/yr. The time series demonstrates rapid terrace formation occurred by vertical incision and lateral erosion, with mass movements contributing to lateral terrace recession. The implications of the data-set are discussed within the context of the Late Quaternary palaeohydrology of Patagonia where lake level falls of 10s to 100s of metres occurred within most large river systems from 42-52 ⁰S demonstrating that base level falls from lake drainage, and catastrophic floods events, were likely a major driver of landscape change in the region.
Is the impact of climate oscillations changing over the Greenland Ice Sheet?
Authors: Silva Tiago , Abermann Jakob , Shahi Sonika , Schöner Wolfgang , Nöel Brice
Published: March 2021

Greenland Block Index (GBI) and North Atlantic Oscillation (NAO) are climate indices widely used for climatological studies especially over the Greenland Ice Sheet (GrIS). Particularly in summer, they are highly and negatively correlated; both have a strong relationship to near surface processes around the GrIS; their magnitude creates non-linear feedbacks and influences the low troposphere, shaping spatial accumulation and ablation patterns.

NAO is a measure of the surface pressure difference over the North Atlantic, providing insight of intensity and location of the jet stream. GBI denotes the general circulation over Greenland at the 500-hPa level and depending on its signal promotes heat and moist advection towards inland.

Based on the 1959-2019 period, the extreme summer melt of 2019 recorded the highest mean summer GBI while the extreme summer melt of 2012 recorded the lowest mean summer NAO. Their impact, however, goes beyond the melting season since the inter-seasonal phase change of these two indices may enhance/ postpone early melt/late refreezing and vice-versa.

Supported by 62 years of high-resolution regional climate model output (RACMO2.3p2), this work uses a statistical approach to analyze inter-seasonal variability of climate oscillations and their impact on the surface energy budget components over the GrIS. Also, teleconnection changes in a changing climate are hypothesized.
Towards a history of Holocene P dynamics for the Northern Hemisphere using lake sediment geochemical records
Authors: Moyle Madeleine , Boyle John , Chiverrell Richard
Published: March 2021

Present day phosphorus (P) enrichment and accelerated P cycling are changes superimposed on a dynamic Holocene history of landscape recovery from glaciation, changes in climate, and long-term low-intensity human activity. Knowledge of the changing role of human activity in driving long-term P dynamics is essential for understanding landscape P export and managing both terrestrial and aquatic environments.

Here we apply a simple process model to published lake sediment geochemical P records from 24 sites distributed across the Northern Hemisphere, producing Holocene records of landscape P yield and reconstructions of lake water TP concentrations. These records are a first attempt to produce values for average P export for the Northern Hemisphere over the Holocene, which can be used for constraining long-term landscape P cycling models.

Individual site trajectories of reconstructed Holocene landscape P yield and lake water TP varied systematically, with differences attributable to landscape development history, in turn driven by climate, human impact and other local factors. Three distinct traits are apparent across the records. Mountain sites with minimal direct human impact show falling Holocene P supply, and conform to conceptual models of natural soil development (Trait 1). Lowland sites  where substantial (pre-)historic agriculture was present show progressively increasing Holocene P supply (Trait 2). Lowland sites may also show a rapid acceleration in P supply over the last few centuries, where high intensity land use, including settlements and farming, are present (Trait 3).

This long-term perspective is pivotal to understanding drivers of change in coupled terrestrial and aquatic P cycling. Our reconstructions of long-term lake water TP are particularly useful for target-driven management of aquatic systems.
The PROCRUSTES testbed: tackling cyber-physical risk for water systems
Authors: Moraitis Georgios , Nikolopoulos Dionysios , Koutiva Ifigeneia , Tsoukalas Ioannis , Karavokiros George , Makropoulos Christos
Published: March 2021

Our modern urban environment relies on critical infrastructures that serve vital societal functions, such as water supply and sanitation, which are exposed to various threats of both physical and cyber nature. Despite the progress in protection and increased vigilance, long-established practices within the water utilities may rely on precarious methods for the characterization and assessment of threats, with uncertainty pertaining to risk-relevant data and information. Sources for uncertainty can be attributed to e.g. limited capabilities of deterministic approaches, siloed analysis of water systems, use of ambiguous measures to describe and prioritise risks or common security misconceptions. To tackle those challenges, this work brings together an ensemble of solutions, to form a novel, unified process of resilience assessment for the water sector against an emerging cyber-physical threat landscape e.g., cyber-attacks on the command and control sub-system. Specifically, the proposed framework sets out an operational workflow that combines, inter alia, a) an Agent-Based Modelling (ABM) approach to derive alternative routes to quantify risks considering the dynamics of socio-technical systems, b) an adaptable optimisation platform which integrates advanced multi-objective algorithms for system calibration, uncertainty propagation analysis and asset criticality prioritization and c) a dynamic risk reduction knowledge-base (RRKB) designed to facilitate the identification and selection of suitable risk reduction measures (RRM). This scheme is overarched by a cyber-physical testbed, able to realistically model the interactions between the information layer (sensors, PLCs, SCADA) and the water distribution network. The testbed is designed to assess the water system beyond normal operational capacity. It facilitates the exploration of emergent and unidentified threats and vulnerabilities leading to Low Probability, High Consequence (LPHC) events that systems are not originally designed to handle. It also evaluates alternative risk treatment options against case-appropriate indicators. The final product is the accretion of actionable information to integrate risk into decision-making in a practical and standardized form. Our work envisions to bring forth state-of-art technologies and approaches for the cyber-wise water sector. We aspire to enhance existing capabilities for large utilities and enable small and medium water utilities with typically less resources, to reinforce their systems’ resilience and be better prepared against cyber-physical and other threats.
Statistical modeling of fire brigade operations with respect to extreme precipitation events over Berlin
Authors: Pasternack Alexander , Langer Ines , Rust Henning W. , Ulbrich Uwe
Published: March 2021

Large cities and urban regions are highly sensitive to impacts caused by extreme events (e.g. heavy rainfall). As problems caused by hazardous atmospheric events are expected to intensify due to the Anthropogenic Climate Change, adequate adaptation planning of urban infrastructure is needed. Planning adaptations not only requires further research on potential impacts under changing climate conditions as a basis, but also a check of the practical feasibility for stakeholders.

Under the BMBF research program “Urban Climate Under Change” ([UC]²), we relate heavy precipitation events over Berlin to the respective fire brigade operations. Here, the precipitation data are based on temporally high resolved radar data. The fire brigade operation data are available on time and location, but the number of recorded events is small, and their distribution is highly overdispersive compared to a Poisson model. To account for this problem we apply a two part hurdle model with one part modeling the probability of the occurrence of fire brigade operations and one part modeling the actual number of operations given that at least one operation occurs. In the corresponding statistical models the parameters of the distributions are described by additive predictors, which are based on precipitation duration and intensity as well as building density. Based on 10 years of data with a cross validation setup, both the occurrence model and the model for the number of operations significantly outperform the reference climatology for certain areas over Berlin.
Fire weather thresholds and burnt area in Portugal
Authors: Calheiros Tomás , Benali Akli , Silva João Neves , Pereira Mário , Nunes João Pedro
Published: March 2021

Fire strongly depends on the weather, especially in Mediterranean climate regions with rainy winters but dry and hot summers, as in Portugal. Fire weather indices are commonly used to assess the current and/or cumulative effect of weather conditions on fuel moisture and fire behaviour. The Daily Severity Rating (DSR) is a numeric rating of the difficulty of controlling fires, based on the Canadian Fire Weather Index (FWI), developed to accurately assess the expected efforts required for fire suppression. Recently, the 90th percentile of DSR (90pDSR) was identified as a good indicator of extreme fire weather and well related to the burnt area in some regions of the Iberian Peninsula. The purposes of this work were: 1) to verify if this threshold is adequate for all continental Portugal; 2) to identify and characterize local variations of this threshold, at a higher spatial resolution; and, 3) to analyse other variables that can explain this spatial heterogeneity.

We used fire data from the Portuguese Institute for the Conservation of Nature and Forests and weather data from ERA5, for the 2001 – 2019 study period. We also used the Land Use and Occupation Charter for 2018 (COS2018), provided by the Directorate-General for Territory, to assess land use and cover in Portugal. The meteorological variables to compute the DSR are air temperature, relative humidity, wind speed and daily accumulated precipitation, at 12 UTC. DSR percentiles (DSRp) were computed for summer period (between 15th May and 31st October) and combined with large (>100 ha) burnt areas (BA), with the purpose to identify which DSRp value is responsible of a large amount of BA (80 or 90%). Cluster analysis was performed using the relation between DSRp and BA, in each municipality of Continental Portugal.

Results reveal that the 90pDSR is an adequate threshold for the entire territory. However, at the municipalities’ level, some important differences appear between DSRp thresholds that explain 90 and 80% of the total BA. Cluster analysis shows that these differences justified the existence of several statistically significant clusters. Generally, municipalities where large fires take place in high or very high DSRp are located in north and central coastal areas, Serra da Estrela, Serra de Montejunto and Algarve. In contrast, clusters where large fires where registered with low DSRp appear in northern and central hinterland. COS2018 data was assessed to analyse if and how the vegetation cover type influences the clusters’ distribution and affects the relationship between DSRp and total BA. Preliminary results expose a possible vegetation influence, especially between forests and shrublands.
Tectonic escape of Sicily Microplate in the context of Africa-Europe collision
Authors: Penza Giulia , Pierantoni Pietro Paolo , Macchiavelli Chiara , Turco Eugenio
Published: March 2021

Sicily is in the centre of an area where complex geodynamic processes work together, these are: the Tyrrhenian-Apennine System evolution, the African-Ionian slab subduction and Africa-Europe collision.

During the last 5 Ma it was involved in a process of escape towards east-southeast: while on one side Africa acted as an intender pushing toward north, on the other side the fragmentation and retreat of the African-Ionian slab created space to the east.

The aim of this study is to reconstruct the kinematic evolution of Sicily, here considered as an independent plate starting from 5 Ma ago, and its role in the context of the Tyrrhenian-Apennine system.

The plates and microplate involved in the evolution are Europe, Africa and Calabria. The boundaries between these and Sicily are the margin of the Sicily microplate and are lithospheric structures known from the literature and identifiable from high resolution bathymetric maps, seismic sections, geodetic data, focal mechanism of recent earthquakes, gravimetric maps, lithosphere thickness maps and so on.

Briefly the margin between Sicily and Europe is along the Elimi chain, a E-W trending morpho-structure with transpressive kinematics, the margin with Calabria microplate is along the right-lateral Taormina line and the margin with Africa is expressed along the Malta Escarpment, south of Etna Mount, with transpressive kinematics and along the Sicily Channel, where a series of troughs (Pantelleria, Linosa and Malta) were interpreted in literature as pull-apart basins related to a dextral trascurrent zone.

The Euler pole of rotation between Sicily and Africa was found starting from the structures in the Sicily Channel and using the GPlates software, then we were able to find also Sicily-Europe and Sicily-Calabria poles and the respective velocity vectors and to compare these with the geological data and better refine the model.
Joint return periods of critical thresholds of duration and severity of crop water stress in some areas of central Italy
Authors: Vergni Lorenzo , Todisco Francesca
Published: March 2021

As many other natural hazards, the crop water stress has a typical multivariate nature, i.e., it is characterized by the contemporary presence of multiple characteristics correlated with each other (e.g., duration, severity, peak, areal extension, etc.). In this situation, a risk analysis based on a traditional univariate approach is inadequate for a complete interpretation of the phenomenon. Copula models can effectively solve the probabilistic joint analysis of two or more random correlated variables. Copulas are functions that join univariate probability distributions to form multivariate probability distributions, modelling the dependence structure among random variables independently of their marginal distributions. This work illustrates how the joint probability and return periods of the Duration (D, days) and Severity (S, mm) of the crop water stress can be used to obtain information useful in defining drought management strategies. The case study refers to some localities of central Italy and olive crops, widely cultivated in the region considered, mainly under rainfed conditions. In the case study, 65 years of daily precipitation and maximum and minimum temperature were used to obtain a rough estimation (following the FAO 56 guidelines) of the daily soil water dynamics (SWt), available for the olive crops at each locality considered. Then, by applying the Theory of Runs to SWt, with a threshold equal to the crop critical point (SWcrit), the water stress events were identified and characterized by their D (days) and S (i.e., the cumulative evapotranspiration deficit, mm) for each locality. A 2-parameter Gamma distribution was fitted to both D and S, whilst a Frank copula modelled their dependence structure. These joint probability models were then used to quantify the return periods associated with specific user-defined critical threshold events; in this work, the critical threshold events were simply defined on the basis of a statistical approach (e.g., combining the values of D and S corresponding to the 90th percentiles). However, in a real case application, the critical thresholds could arise from considerations on the crop impacts deriving from specific D and S values. Despite the modest areal extension of the case study, results show that the climatic conditions significantly affect the bivariate return period of the critical threshold events, which varies between 3 and 15 years in the localities considered. We also evaluated the return time increment due to some drought management strategies, such as the application of rescue irrigation. For example, the application of an irrigation volume of 50 mm in the mid of the growing season is able to produce a relevant change of the return period, thus varies between 5 and 77 years.

 
The contribution of biogenic organic matter to aggregation in soil - a review
Authors: Guhra Tom , Stolze Katharina , Totsche Kai Uwe
Published: March 2021

Soil organisms (plants, invertebrates, and microorganisms) are involved in soil structuring and are key factors of aggregation through bioturbation, organic matter (OM) decomposition, and secretion of biogenic OM (e.g., root exudates, mucus and extracellular polymeric substances). At the field scale, soil quality, functions, as well as nutrient cycling usually benefit from the activity of soil organisms that frequently cause substantial changes to soil properties by the formation of aggregates. The biogenic formation pathway of soil aggregates reflects a cascade of small-scale sub-processes (e.g., OM supply, OM adsorption, organo-mineral association formation, their transport, immobilization, and involvement into aggregate structure) that are often portrayed solitarily in literature and demand for a comprehensive framework that consistently describes their synergies and dependencies. Particularly, the role of complexly composed biogenic OM as bridging/aggregation agent is controversially discussed in literature, as they may promote as well as inhibit aggregation at the same time. This non-uniform behavior is controlled by the complex interplay of milieu parameters (e.g., ionic strength, temperature, pH and redox-potential) and the physicochemical properties of biogenic OM (e.g., protein-to-polysaccharide-ratio, molecular weight of biopolymers, functional groups, and biopolymer structure). Hence, we discuss biogenic OM with respect to the three different roles in aggregation which can be identified from literature: (I) as bridging agent which permits the aggregation due to attraction and surface modifications, (II) as separation agent which favors the formation, mobility and transport of organo-mineral associations and inhibits their further involvement into aggregates, and (III) as gluing agent which mediates aggregate stability, after an external force provokes a close approach of soil particles. In natural systems, OM may take these roles simultaneously and with varying degree across spatiotemporal scales. Considering this for the discussion of the role of biogenic OM in soil aggregate formation, we will achieve a more detailed and interdisciplinary understanding of its pathways into soil aggregates, which can help to draw comprehensive conclusions from lab and field-scale studies, prospectively.
Projected disruption in seasonal timing of Arctic Ocean pCO2
Authors: Orr James , Kwiatkowski Lester
Published: March 2021

Ocean acidification implies long-term changes in ocean CO2 system variables modulated by changes in seasonal amplitudes. Further modulation, yet unexplored, may come from changes in timing of the annual cycle. For the CO2 partial pressure (pCO2), a winter high and summer low are observed in Arctic Ocean surface waters because thermal effects are outweighed by those from biology. Here the same timing was found with 9 Earth system models under historical forcing. Yet under a high-end CO2 emission scenario, those models project that the summer low (relative to the annual mean) eventually reverses sign across most of the Arctic Ocean. In most models, that sign reversal inverses the chronological order of the annual high and low. The high moves from spring to summer and the low moves from summer to spring. The cause is the projected dramatic warming in summer sea surface temperature provoked by earlier retreat of seasonal sea ice. The increase in the summer pCO2 extreme over this century is 29±9% greater than if there had been no change in seasonal timing, only the enhanced sensitivity of pCO2 to its driving variables. Thus the projected change in extreme summer pCO2 is 150±50 μatm higher. Outside of the Arctic Ocean, projected changes in seasonal timing of pCO2 are small.
Machine learning-based grain size mapping from satellite images 
Authors: Marchetti Giulia , Bizzi Simone , Belletti Barbara , Lastoria Barbara , Mariani Stefano , Casaioli Marco , Comiti Francesco , Carbonneau Patrice
Published: March 2021

A comprehensive understanding of river dynamics requires the quantitative knowledge of the grain size distribution of bed sediments and its variation across multiple temporal and spatial scales. Several techniques are already available for grain size assessment based on field and remotely sensed data. However, the existing methods permit to cover small areas and short time scale, thus the operational measurement of grain size distribution of river bed sediments at the catchment scale remains an open problem. A solution could be the use of satellite images but very limited investigations have been carried out so far on the use of satellite-based sub-pixel mapping of river characteristics relevant to ecohydraulic processes.

In this study, we propose a new approach to retrieve sub-pixel scale grain size classes information from Sentinel 2 imagery building upon a new image-based grain size mapping procedure. Four Italian gravel-bed rivers featuring different morphology were selected to conduct UAV acquisitions and extract ground truth grain size data from the near-ground images, by photo-sieving techniques. We generated grain size maps at the resolution of 2 cm on river bars in each study site by exploiting image texture measurements, and subsequently resampled and co-registered the grain size maps with Sentinel 2 data resolution.

Relationships between the grain sizes measured and the reflectance values in Sentinel 2 imagery - available in 11 bands super resolved at 10 m resolution – were analyzed. Based on these, our first results show statistically significant predictive models (cross validation results: MAE of 3.38 ± 13.4 mm and R2=0.48) by using a machine learning framework (Support Vector Machine) to retrieve grain size classes from reflectance data.

Our proposed approach based on freely available satellite data calibrated by low-cost automated drone technology can provide reasonably accurate estimates of surface grain size for bar sediments in medium to large river channels, over lengths of hundreds of kilometers. Moreover, the proposed methodology is easily replicable to other natural environments where an extensive grain size distribution assessment is crucial to understand geomorphic processes, thus providing a new technique for collecting such precious data and support studies of landscape evolution.
Explaining the continuing inflation of Montserrat
Authors: Neuberg Jurgen , Taisne Benoit
Published: March 2021

Soufrière Hills volcano on Montserrat in the West Indies showed five episodes of magma extrusion and as many pauses in its 25 years of volcanic activity. This eruptive behaviour exhibited cyclic deformation pattern where extrusive “phases” showed island-wide deflation and all “pauses” have been linked to inflation, the last of which remains ongoing. Several models have been developed over the years; all based on magma intrusion and extrusion, into, or from one or several reservoirs, respectively. Addressing the entire eruptive history, we explore in this presentation several alternative models ranging from the continuous magma influx at depth to the extreme case where intrusion of fresh magma has ceased years ago, while the inflation is continuing. Both, purely elastic and visco-elastic rheologies are explored.
Patterns in woody vegetation cover across forests of a main Mediterranean island in relation to precipitation regime.
Authors: Cipolla Sara Simona , Montaldo Nicola
Published: March 2021

In water-limited ecosystems such as those encountered on Mediterranean mountainous areas of shallow soil, climate-induced changes in precipitation regime are expected to influence the ability of remnants of native forests to resist or adapt to predicted reduced precipitation scenarios. The objective of this work was to understand the role of precipitation and physiographic ecosystem properties in woody cover spatial variability of Mediterranean sclerophyllous forests located within main protected areas of the Sardinia Island (Italy), an excellent reference condition for Mediterranean hydrologic studies due to the relatively low urbanization and human activities. Analyzed forests differ in altitude (0-1500 slm.), mean annual precipitation (450-1200 mm) over 95 years of daily data, exposition, dominant species, density, and soil thickness. Forests have been broken down into 30 * 30 m plots based on their type. Using data from the Landsat satellite sensors, temporal trends in the NDVI (Normalized Difference Vegetation Index) were quantified. We related these trends with different environmental variables to understand the effects of the variation of precipitation regimes and forest type on woody cover density. A significant direct effect of drought has been observed in the dry 2017 in all forests resulting in a significantly reduced NDVI values especially on south facing slopes plots and low soil thickness plots. On the contrary forest canopy were more stable on mesic habitats demonstrating that the availability of soil humidity is more important than solar radiation. Finally, the lowest values of NDVI were observed in semi-arid sclerophyllous forest dominated by species tolerant to drought and very thin stony soil layers. The identification of the factors that contribute the most to the increase in the vulnerability and the decrease of tree cover density of forests will allow to optimize planning and management strategies also under further drier climate changes prospective.
Evolution and hydrological importance of debris-covered glaciers and ice-debris landforms
Authors: Bolch Tobias , King Owen , Ferguson James , Mölg Nico , Vieli Andreas , Pellicciotti Francesca
Published: March 2021

Debris-covered glaciers and ice-debris landforms such as rock glaciers are common in many mountain areas of Earth, are important for the debris transport system and contain a significant amount of ice. The presence, amount and characteristics of debris can strongly alter ice melt and the evolution of glaciers and ice-debris landforms. However, debris cover and debris content exhibits strong spatial variations. To understand the evolution and physiognomies of ice-debris complexes it is important to consider both debris supply and transport as well as deposition, which are impacted by climatic conditions, topography and lithology. A holistic approach to the investigation of these coupled complex systems seems thus crucial.

In this talk we present findings from our work based on in-situ investigations (e.g. geophysical methods), multitemporal high resolution remotely sensed imagery (including historical aerial images, Corona KH 4 images and recent  data) and modelling (including surface ablation, englacial debris transport and ice flow) conducted on selected debris-covered glaciers and ice debris landforms worldwide.

Results show that a significant amount of ice is buried beneath debris cover in glacier forefields, ice cored moraines and rock glaciers under permafrost conditions. The response of rock glaciers to climate change is heterogenous with overall increasing velocities and on average only slight surface elevation changes. Slight increases in surface elevation occur their termini while debris-covered glaciers show on average a clear signal of surface lowering and decreasing velocities. The heterogeneity of debris cover can to a large extend be explained by the different debris sources and the characteristics of the headwalls while englacial and supraglacial streams favour the evolution of rough surface topography on debris-covered glaciers with the presence of ice cliffs. The findings will be illustrated with specific examples from the Swiss Alps, the Himalaya and the Tien Shan.
Prevention of Debris Flow from Inactive, Usually Dry Catchment in zero-order basin
Authors: Horiguchi Toshiyuki , Kokuryo Hiroshi , Ishikawa Nobutaka
Published: March 2021

The human settlement tend to be close to a mountainous area all over the world. The prevention concept is necessary to mitigate or prevent the origin occurrence of debris flow in zero-order basin. The zero-order basin is a mountain stream that is unclear valley topography, and don’t flow always running water. Although it is designated as a debris flow prone zone, the area of the basin is small, and the arrangement of sabo dam is difficult, and there are a lot of mountain streams which are judged that the facility function is hard to be fully demonstrated for the actual phenomenon of the sediment. The prevention and/or mitigation of measurement facilities is required. This study presents a full design of a protection barrier against debris flow, including woody debris in small, inactive, and usually dry catchments in small-scale torrents or zero order basin. The concept of performance-based design is proposed for a protection barrier as exemplifying slit barrier in small torrent. In addition, the safety performance for two types of a slit barrier is verified to protect debris flow under the situation of three difference small torrents.
How retrogressive thaw slumps change over time - a study from Herschel Island (Canada) using 3D electrical resistivity tomography (ERT)
Authors: Eppinger Saskia , Krautblatter Michael
Published: March 2021

Retrogressive thaw slumps (RTS) are a common thermokarst landform along arctic coastlines with an increasing thermoerosional activity. They underlay a rapid change in topographical as well as internal structures due to various external factors, e.g. changing climate conditions.

In 2011 and 2019 electrical resistivity tomography (ERT) measurements were carried during field campaigns to Herschel Island (Yukon Territory, Canada). Transects crossing Herschel Islands largest slump were performed, as well as quasi 3D-ERT-profiles. For better understanding these changes we compared the datasets focusing on the internal structures just as variations in the topography.

The aim for our study is gaining an impression of structural and topographical changes over several years, leading towards a better comprehension of long-term processes in retrogressive thaw slumps.
Comparison of spectral methods for the evaluation of Stokes integral  
Authors: Narayan Avadh Bihari , Tiwari Ashutosh , Sharma Govind , Devaraju Balaji , Dikshit Onkar
Published: March 2021

The spherical approximation of the fundamental equation of geodesy defines the boundary value problems. Stokes’s integral provides the solution of boundary value problems that enables the computation of geoid from the properly reduced gravity measurements to the geoid. The stokes integral can be evaluated by brute-force numerical integration, spectral methods, and least-squares collocation. There is a trade-off between computation time and accuracy when we chose numerical integration technique or any spectral method. This research will compare time complexity and the accuracy of different spectral methods (1D-FFT, 2D-FFT, Multi-band FFT) and numerical integration technique for the region in the lower Himalaya, around Nainital, Uttarakhand, India. 
Startegic framework for integrated flood Disaster modelling over Bangalore city of India
Authors: Purwar Smrati , Mohapatra Gyanendranath , Vasudevan Rakesh
Published: March 2021

Hydro-meteorological disasters, particularly the extreme rainfall events (EREs) and associated flash floods, are very frequent in the major metro cities in India during recent years and in many occasions they cause massive destruction to life and property which in long run make adverse socio-economic impacts over the country. Hence, it makes formost importance and has great societal relevance to modellers working such area to develop an advance prediction system for such disasters in India.A strategic framework combining modelling and data analytics is integral part of developing advanced warning system for preparedness during such disasters. In this study, the role of landuse/landcover like built-up, vegetation, barrenland and waterbodies over the Bangalore city in flash flood occurrence is examined using multispectral spatio-temporal satellite data.The recent LULC map evidences a drastic changes in urban landscape that resulted in loss of natural drainage and waterbeds causing frequent floods. Digital Elevation Map (DEM) is analysed to know the  low-lying and high elevation topography compared with  Mean Sea Level(MSL)to quantify the impact of flooding during Extreme Rainfall Events(ERE) on the different part of the Bangalore city. Using Triangular Irregular Network (TIN), flood simulation is carried out for highland and lowlandarea  to study immediate affected areas during EREs Storm Water Modelling  is carried out for different regions in the city to obtain flood pattern, time and volume during selected EREs. The framework developed and simulation results are very useful in generation of management and mitigation strategy by various user agencies.
An over-used ocean island coastal aquifer, Tenerife (Spain) – tracing inputs for improved resource management
Authors: Coldwell Beverley , Cordero María , Pérez Nemesio M. , Amonte Cecilia , Asensio-Ramos María , Melián Gladys , Padrón Eleazar
Published: March 2021

The island of Tenerife (Canary Islands, Spain) relies on basalt-hosted aquifers to provide 90% of water for agriculture and human consumption. The island is characterised by a low-permeability core, overlain by permeable materials which are cut by impermeable dykes. The effect is a compartmentalised aquifer, which is exploited sequentially as each “pocket” of water is exhausted. The island is home to ~1 million people (with an additional 5 million visiting tourists per year), and although rain/snowfall can be heavy in winter storms, it is unpredictable from year to year, and rapid surface water run off occurs due to the steep geography. While net recharge into the upper zones of the Tenerife aquifer have been quantified (around 2 months between intense rainfall and water table fluctuations), water must then follow a tortuous path to recharge lower zones and aquifer “pockets”. Water recharge to the coastal aquifers is also interrupted and extracted during its journey. Human and agricultural pressure is highest near the coast, and has led to intensive exploitation of existing wells and horizontal galleries. In response to the intensification of water extraction and slow recharge rates, marine intrusions into the coastal aquifers of Tenerife have occurred, traditionally recorded by rising chloride levels and resulting in well/gallery closures as well as increased pressure on other extraction sites. However, in a volcanic ocean island setting, natural processes can mimic the appearance of salinisation in a coastal aquifer. Management of aquifer resources require careful consideration of seawater incursions vs. volcanic degassing contributions vs. ocean island rainfall. Full hydrochemical breakdown of 43 coastal aquifer extraction sites reveal seawater intrusion is affecting the western coastal aquifer, with the agreement of multiple parameters. The strontium isotopic signature of well samples was also measured, because it is not subject to the biological or physical fractionation processes of other isotopic systems, thereby forming distinct reservoirs for groundwater (87Sr/86Sr of host rock), and seawater. 87Sr/86Sr signatures suggest the northern coastal aquifers are also subject to seawater incursions. This parameter may be a more sensitive indicator than chlorides and conductivity markers for salinisation, especially in an ocean island environment where coastal aquifers are subject to intensive land use practices, seawater spray, and affected by diffuse volcanic degassing.
Numerical analysis of extreme waves in the North-Western Mediterranean area
Authors: Innocenti Alessio , Brandini Carlo
Published: March 2021

Extreme sea waves have a great impact on the safety of navigation and coastal areas, however their prediction in operational forecasts is difficult and is generally based on spectral indices. Numerical simulations of the free surface Euler equations can be of notable help in the understanding of the statistical properties of a given sea state, and therefore to establish also the probability of extreme or rare events. In this study we performed phase-resolved simulations of wave spectra obtained from a WaveWatch III hindcast, using a Higher Order Spectral Method. We analyzed a number of sea-states occurred in a precise area of the Mediterranean sea, near the location of a reported accident, with the objective of relating the probability of extreme events with different sea state conditions. Namely, we produced statistics of the wave field, calculating crest distributions and the probability of extreme events from the analysis of long time-series of the surface elevation. The results show a good matching between the distributions of the numerically simulated field and theory, namely Tayfun second- and third- order ones, while the Rayleigh distribution gives a significant underestimate. 

We looked for several kind of correlations between spectral quantities like angular spreading and wave steepness and the probability of occurrence of extreme events, finding an enhanced probability for high mean steepness seas and narrow spectra. It is also evident how the case study of the reported accident was not amongst the most dangerous sea states. Relating the skewness and kurtosis of the surface elevation to the wave steepness helped us to understand the discrepancy between theoretical and numerical distributions.
Energetic electrons in solar flares: observational support for acceleration processes linked to magnetic reconnection
Authors: Vilmer Nicole , Musset Sophie
Published: March 2021

Efficient electron (and ion) acceleration is produced in association with solar flares. Energetic particles play a major role in the active Sun since they contain a large amount of the magnetic energy released during flares. Energetic electrons (and ions) interact with the solar atmosphere and produce high-energy X-rays and γ-rays. Energetic electrons also produce radio emission in a large frequency band through gyrosynchrotron emission processes in the magnetic fields of flaring active regions and conversion of plasma waves when e.g. propagating to the high corona towards the interplanetary medium. It is currently admitted that solar flares are powered by magnetic energy previously stored in the coronal magnetic field and that magnetic energy release is likely to occur on coronal currents sheets along regions of strong gradient of magnetic connectivity. However, understanding the connection between particle acceleration processes and the topology of the complex magnetic structures present in the corona is still a challenging issue. In this talk, we shall review some recent results derived from X-ray and radio imaging spectroscopy of solar flares bringing some new observational constraints on the localization of HXR/radio sources with respect to current sheets, termination shocks in the corona derived from EUV observations.
Potential of Rosemary crop in a recovery system of sulfide-rich wastes with designed Technosol
Authors: Arán Diego , Abreu Maria Manuela , Santos Erika S.
Published: March 2021

Nowadays, the strategy for the rehabilitation of contaminated areas must include environmental improvements in an integral way, i.e. all the components of the ecosystem (soil, water and vegetation), and an economic approach. This can be achieved with the combined application of designed Technosols, which are done with organic/inorganic residues without an economic value or valorisation, and an agriculture system with tolerant plants with commercial value. The objective of this study was to evaluate the potential of rosemary crop (Rosmarinus officinalis), a plant species with aromatic and medicinal plant, in a recovery system of sulfide-rich wastes based on the superficial application of Technosols (layer with 20 cm of depth). For this, a mesocosm assay under controlled conditions and greenhouse was carried out during 18 months. The transplant survival and development of rosemary and its ecophysiological status was evaluated as well as the chemical characteristics of the Technosol and mine wastes located under it. Value-added compounds in bioextracts obtained from plants also were evaluated.

The rosemary transplant had 100 % of survival in the Technosol and a great plant growth at medium-long term (18 months) was achieved (Height: 35-57 cm; Fresh biomass of shoots: 76.1-93.8 g). In fact, the plant development was significantly higher than in plants growing in peat under the same conditions (Height <36 cm; Fresh biomass of shoots: 24.1-40.9 g). The roots system in plants growing in the Technosol was dense and with significant growth reaching the mine wastes. This mine wastes already presented a chemical improvement as result of the superficial Technosol application. Plants from Technosol did not show visible signs of phytotoxicity or nutritional deficiency and elements concentrations in shoots were in normal range considered to general of plants species. The Technosol maintained the initial properties and characteristics. The rehabilitation system with a designed Technosol was efficient and can contribute to the recovery, economically atractive, of unproductive and contaminated areas through a rosemary crop.

Acknowledgment: This research was supported by Portuguese funds, through Fundação para a Ciência e Tecnologia, within the scope of the project UID/AGR/04129/2020.
The coral reef-dwelling Peneroplis spp. shows calcification resilience to ocean acidification conditions - results from culture experiments
Authors: Charrieau Laurie , Kimoto Katsunori , Dissard Delphine , Below Beatrice , Fujita Kazuhiko , Nagai Yukiko , Toyofuku Takashi
Published: March 2021

Ocean acidification is a consequence of current anthropogenic climate changes. The concomitant decrease in pH and carbonate ion concentration in sea water may have severe impacts on calcifying organisms. Coral reefs are among the first ecosystems recognized vulnerable to ocean acidification. Within coral reefs, large benthic foraminifera (LBF) are major calcium carbonate producers.

The aim of this study was to evaluate the effects of varying pH on survival and calcification of the symbiont-bearing LBF species Peneroplis spp. We performed culture experiments to study their resistance to ocean acidification conditions, as well as their resilience once placed back under open ocean pH (7.9).

After three days, small signs of test decalcification were observed on specimens kept at pH 7.4, and severe test decalcification was observed on specimens kept at pH 6.9, with the inner organic lining clearly appearing. After 32 days under pH 7.4, similar strongly decalcified specimens were observed. All the specimens were alive at the end of the experiment. This result demonstrates the resistance of Peneroplis spp. to an acidified pH, at least on a short period of time.

After being partially decalcified, some of the living specimens were placed back at pH 7.9. After one month, the majority of the specimens showed recalcification features, mostly by addition of new chambers. The trace elements concentrations of the newly formed chambers were analysed by LA-ICPMS. Interestingly, more chambers were added when food was given, which highlights the crucial role of energy source in the recalcification process. Moreover, the newly formed chambers were most of the time abnormal, and the general structure of the tests was altered, with potential impacts on reproduction and in situ survival. In conclusion, if symbiont-bearing LBF show some resistance and resilience to lowered pH conditions, they will remain strongly affected by ocean acidification.