bluuebunny/crossref_metadata_2025 huggingface dataset:
SourcE and impact of greeNhousE gasses in AntarctiCA: the Seneca project
Authors: Ruggiero Livio , Sciarra Alessandra , Mazzini Adriano , Mazzoli Claudio , Romano Valentina , Tartarello Maria Chiara , Florindo Fabio , Ascani Massimiliano , Wilson Gary , Dagg Bob , Hardie Richard , Anderson Jacob , Worthington Rachel , Lupi Matteo , Bigi Sabina , Ciotoli Giancarlo , Graziani Stefano , Fischanger Federico , Sassi Raffaele
Published: March 2020

Current global climate changes represent a threat for the stability of the polar regions and may result in cascading broad impacts. Studies conducted on permafrost in the Arctic regions indicate that these areas may store almost twice the carbon currently present in the atmosphere. Therefore, permafrost thawing may potentially cause a significant increase of greenhouse gases concentrations in the atmosphere, exponentially rising the global warming effect. Although several studies have been carried out in the Arctic regions, there is a paucity of data available from the Southern Hemisphere. The Seneca project aims to fill this gap and to provide a first degree of evaluations of gas concentrations and emissions from permafrost and/or thawed shallow strata of the Dry Valleys in Antarctica. The Taylor and Wright Dry Valleys represent one of the few Antarctic areas that are not covered by ice and therefore represent an ideal target for permafrost investigations.

Here we present the preliminary results of a multidisciplinary field expedition conducted during the Antarctic summer in the Dry Valleys, aimed to collect and analyse soil gas and water samples, to measure CO2 and CH4 flux exhalation, to investigate the petrological soil properties, and to acquire geoelectrical profiles. The obtained data are used to 1) derive a first total emission estimate for methane and carbon dioxide in this part of the Southern Polar Hemisphere, 2) locate the potential presence of geological discontinuities that can act as preferential gas pathways for fluids release, and 3) investigate the mechanisms of gas migration through the shallow sediments. These results represent a benchmark for measurements in these climate sensitive regions where little or no data are today available.
Coupled Interannual Variability of Wind and Sea Surface Temperature in the Caribbean Sea and the Gulf of Mexico
Authors: Rodríguez-Vera Geidy , Romero-Centeno Rosario , Castro Christopher L. , Mendoza Castro Víctor
Published: March 2020

This work describes dominant patterns of coupled interannual variability of the 10-m wind and sea surface temperature in the Caribbean Sea and the Gulf of Mexico (CS&GM) during the period 1982–2016. Using a canonical correlation analysis (CCA) between the monthly mean anomalies of these fields, four coupled variability modes are identified: the dipole (March–April), transition (May–June), interocean (July–October), and meridional-wind (November–February) modes. Results show that El Niño–Southern Oscillation (ENSO) influences almost all the CS&GM coupled modes, except the transition mode, and that the North Atlantic Oscillation (NAO) in February has a strong negative correlation with the dipole and transition modes. The antisymmetric relationships found between the dipole mode and the NAO and ENSO indices confirm previous evidence about the competing remote forcings of both teleconnection patterns on the tropical North Atlantic variability. Precipitation in the CS and adjacent oceanic and land areas is sensitive to the wind–SST coupled variability modes from June to October. These modes seem to be strongly related to the interannual variability of the midsummer drought and the meridional migration of the intertropical convergence zone in the eastern Pacific. These findings may eventually lead to improving seasonal predictability in the CS&GM and surrounding land areas.
Porous media as a canvas for hydro-bio-geo-chemical processes: Facing the challenges
Authors: Sanchez-Vila Xavier
Published: March 2020

The more we study flow and transport processes in porous media, the larger the number of questions that arise. Heterogeneity, uncertainty, multidisciplinarity, and interdisciplinarity are key words that make our live as researchers miserable… and interesting. There are many ways of facing complexity; this is equivalent as deciding what colors and textures to consider when being placed in front of a fresh canvas, or what are the sounds to include and combine in a music production. You can try to get as much as you can from one discipline, using very sophisticated state-of-the-art models. On the other hand, you can choose to bring to any given problem a number of disciplines, maybe having to sacrifice deepness in exchange of the better good of yet still sophisticated multifaceted solutions. There are quite a number of examples of the latter approach. In this talk, I will present a few of those, eventually concentrating in managed aquifer recharge (MAR) practices. This technology involves water resources from a myriad of perspectives, covering from climate change to legislation, from social awareness to reactive transport, from toxicological issues to biofilm formation, from circular economy to emerging compounds, from research to pure technological developments, and more. All of these elements deserve our attention as researchers, and we cannot pretend to master all of them. Integration, development of large research groups, open science are words that will appear in this talk. So does mathematics, and physics, and geochemistry, and organic chemistry, and biology. In any given hydrogeological problem you might need to combine equations, statistics, experiments, field work, and modeling; expect all of them in this talk. As groundwater complexity keeps amazing and mesmerizing me, do not expect solutions being provided, just anticipate more and more challenging research questions being asked.
Characteristics of the Concentric Eyewall Structure of Super Typhoon Muifa during Its Formation and Replacement Processes
Authors: Liu Yudi , Li Dawei , Huang Lang
Published: March 2020

To explore the characteristics of the concentric eyewall of a typhoon during its formation and replacement processes, with Super Typhoon Muifa in 2011 as the example case, the Weather Research and Forecast (WRF) mode was used to carry out a numerical simulation to reproduce the entire formation and replacement processes of the concentric eyewall. The physical quantities such as the tangential wind speed, radar echo, radial wind speed, vertical wind speed, and potential vortex were diagnosed and analyzed. The results of the analysis show that the outward expansion of the isovelocity in the lower troposphere was the early signal of the formation of the outer eyewall. After the outer eyewall formed, there was a center of second-highest tangential wind speed in the corresponding area. The second-highest wind speed increased as the strength of the outer eyewall increased, and the position of the second-highest wind speed center was retracted with the retraction of the outer eyewall. The tangential wind speed of the moat area was smaller than that corresponding to the concentric eyewall and this feature gradually disappeared with the increase of the height. The echo in the moat area was weak, and this characteristic was particularly evident when the moat area was relatively wide and the outer eyewall was relatively strong. With the formation and development of the outer eyewall, the intensity of the inflow in the boundary layer corresponding to the inner eyewall was reduced, the intensity of the outflow in the upper layers declined, and the intensities of the inflow and outflow corresponding to the outer eyewall were enhanced. After the second outer eyewall matured, there was a significant inflow in the upper layer of the moat area. Once the outer eyewall formed, a large amount of hydrometeors appeared in the corresponding area, and there was a strong ascending motion inside that area. The strength of the ascending motion and the content of hydrometeors increased as the outer eyewall increased. When the moat area was relatively wide, the divergent airflow generated by the developed outer eyewall in the upper layer would produce a significant descending motion in the moat area.
Lower Ionospheric turbulence variations during the intense seismic activity of the last half of 2019 in the broader Balkan region.
Authors: Contadakis Michael E. , Arabelos Demetrios , Vergos George , Scordilis Emmanuel M.
Published: March 2020

In this paper, we investigate the ionospheric turbulence from TEC observations, before and during the intense seismic activity of September 2019 at Albania (main shock at l=19.445oE, j=41.372o N, Mw=5.6)  and at Marmara sea (main shock at l=28.19 oE, j=40.872oN, Mw=5.7), as well as of November 2019 at Albania (main shock at l=19.470oE, j=41.381oN, Mw=6.4), and at Bosnia-Herzegovina (main shock at l=17.961oE, j=43.196oN, Mw=5.4).

The Total Electron Content (TEC) data of 6 Global Positioning System (GPS) stations of the EUREF network, which are being provided by IONOLAB (Turkey), were analysed using Discrete Fourier Analysis in order to investigate the TEC variations. The results of this investigation indicate that the High- Frequency limit fo, of the ionospheric turbulence content, increases by aproaching the site and  the time of the earthquake occurrence, pointing to the earthquake location (epicenter). We conclude that the LAIC mechanism, through acoustic or gravity wave, could explain this phenomenology. In addition the proximity of the tectonic active areas to the GPS stations offer us an opportunity to discriminate the origin of the disturbances
An investigation into the potential uses of the waste aggregate stockpile at Belgard quarry.
Authors: Bannon Ciara
Published: March 2020

Quarries produce huge volumes of waste aggregate during the processing and screening of rock and Belgard quarry in west Dublin, Ireland, is no different. Operated by Roadstone since the 1970s, the waste stockpile at Belgard, largely composed of weaker limestones and mudstones, has grown to considerable size and finding a potential use for this material is proving challenging. Although various internal studies have identified some potential uses of the coarse aggregate chips, 45% of the stockpile consists of <6.3mm sized chips and fine material and any processing of the stockpile to obtain the coarse chips would be cost inhibitive due to the volume of the currently unusable fine material. This study therefore focused on identifying an application for the <6.3mm material. The potential for this material to act as a treatment for acid mine drainage was investigated by using water from the Avoca river and several of the metal contaminants significantly decreased in their concentration after filtering through a channel of <6.3mm screenings. The screenings were also observed to decrease the pH of both river and tap water. A subsidiary study on the potential fertilising effects of the <6.3mm material was conducted and the growth media consisting of 50% screenings, 50% compost, outperformed 100% compost when a comparison of grass height and both above and below ground dry mass was conducted. Several possible applications of the screenings were identified as part of this study however any environmental impacts would need to be fully understood before such use. 
Сomparison of ion pressure variations derived from Cluster/CODIF and the combined Cluster/CODIF&RAPID data during prolonged dipolarizations in the near Earth magnetotail
Authors: Malykhin Andrey , Grigorenko Elena , Kronberg Elena , Daly Patrick
Published: March 2020

Usually, for the plasma pressure estimation in the plasma sheet  ion observations in the energy range up to ~40 keV are used. However, the thermal part of the distribution function can pass beyond the high energy threshold of an instrument during active events like dipolarizations. In such cases the entire ion population is not measured and the ion pressure can be underestimated. We study this problem by using Cluster mission observations provided  by two instruments: thermal plasma instrument - CODIF (up to 38 keV) and suprathermal instrument - RAPID (from 40 up to 1500 keV). We analyzed 11 dipolarization events and showed that in all events the maximum of ion energy flux was shifted to high energy threshold of CODIF instrument. Simultaneously, the energy flux increase in suprathermal energy range was observed by RAPID. For H+ and O+ ion components we calculate the pressure of suprathermal population and showed that the total pressure estimated by using both CODIF and RAPID instruments at some intervals exceeds the pressure estimated only from CODIF data up to 5 times. The superposed epoch analysis applied to 11 dipolarization events from our data base showed that the total pressure of H+ and O+ ion components can be in 2-5 times underestimated in the course of dipolarization.
Shortening of Archaean and Paleoproterozoic continental lithospheres: large strains, but no orogeny
Authors: Gapais Denis
Published: March 2020

Shortening of Archaean and Paleoproterozoic continental lithospheres: large strains, but no orogeny

 

 

Denis Gapais1, Jonathan Poh1, Philippe Yamato1, Thibault Duretz1, Florence Cagnard2

 

(1) Géosciences Rennes, UMR CNRS 6118, Université de Rennes 1, 35042 Rennes cedex, France

 

(2) Bureau de Recherche Géologique et minière, 3 avenue Claude-Guillemin, BP 36009 45060 Orléans Cedex 2, France

 

 

Denis.gapais@univ-rennes1.fr, jonathanpoh87@gmail.com, philippe.yamato@gmail.com, thibault.duretz@univ-rennes1.fr, f.cagnard@brgm.fr

 

 

In many ancient deformation belts of Archaean and Paleoproterozoic age (e.g. Terre Adélie in East Antarctica, Finnish Svecofennides in Southern Finland, Murchison Belt in South Africa, Thompson Nickel Belt in Manitoba, Dharwar Craton in western India, Abitibi sub-Province in Québec, Trans-Hudson belt of Canada, Trans-Amazonian belt of Suriname), latest recorded deformations are compressive or transpressive. In these belts that involved hot and weak continental crusts, deformations are distributed with basically vertical tectonics and important crustal thickening. On the other hand, there is no evidence of syn-orogenic extension or late-orogenic collapse, as classically observed in modern orogens where extensional detachments are widespread.

Analogue and numerical models emphasize that shortening of weak and hot lithospheres basically favour downward motions, which result in limited topographies. Field evidence further point to metamorphic isogrades rather parallel to the Earth surface at belt scale. Hence, metamorphic conditions are rather monotonous at the scale of individual belts, with limited metamorphic jumps and typical P-T paths with no significant adiabatic retrograde segments. Consistently, localized deep detrital sedimentary basins like foreland or intra-mountain basins, are not documented. Sedimentary records rather suggest distributed sedimentation processes. In addition, several lines of evidence tend to point out that cooling of ancient hot deformation belts was rather slow, which is consistent with distributed topographies and long-lasting erosion-driven exhumation processes.

 On these bases, we propose that gravity-driven collapse had no reason to occur in ancient hot deformation belts because important topographic gradients and orogeny could not develop as observed in modern mountain chains.
Asynchronous Antarctic and Greenland ice-volume contributions to the last interglacial sea-level highstand
Authors: Rohling Eelco , Hibbert Fiona
Published: March 2020

Sea-level rise is among the greatest risks that arise from anthropogenic global climate change. It is receiving a lot of attention, among others in the IPCC reports, but major questions remain as to the potential contribution from the great continental ice sheets. In recent years, some modelling work has suggested that the ice-component of sea-level rise may be much faster than previously thought, but the rapidity of rise seen in these results depends on inclusion of scientifically debated mechanisms of ice-shelf decay and associated ice-sheet instability. The processes have not been active during historical times, so data are needed from previous warm periods to evaluate whether the suggested rates of sea-level rise are supported by observations or not. Also, we then need to assess which of the ice sheets was most sensitive, and why. The last interglacial (LIG; ~130,000 to ~118,000 years ago, ka) was the last time global sea level rose well above its present level, reaching a highstand of +6 to +9 m or more. Because Greenland Ice Sheet (GrIS) contributions were smaller than that, this implies substantial Antarctic Ice Sheet (AIS) contributions. However, this still leaves the timings, magnitudes, and drivers of GrIS and AIS reductions open to debate. I will discuss recently published sea-level reconstructions for the LIG highstand, which reveal that AIS and GrIS contributions were distinctly asynchronous, and that rates of rise to values above 0 m (present-day sea level) reached up to 3.5 m per century. Such high pre-anthropogenic rates of sea-level rise lend credibility to high rates inferred by ice modelling under certain ice-shelf instability parameterisations, for both the past and future. Climate forcing was distinctly asynchronous between the southern and northern hemispheres as well during the LIG, explaining the asynchronous sea-level contributions from AIS and GrIS. Today, climate forcing is synchronous between the two hemispheres, and also faster and greater than during the LIG. Therefore, LIG rates of sea-level rise should likely be considered minimum estimates for the future.
Surface modification of bioaerosol by physical, chemical, and biological ageing processes
Authors: Zhang Minghui , Khaled Amina , Amato Pierre , Delort Anne-Marie , Ervens Barbara
Published: March 2020

Primary biological aerosol particles (PBAP) are a significant fraction of total atmospheric aerosol burden and can exhibit unique properties in terms of ice nucleation. In current atmospheric models, it is usually assumed that the physicochemical properties of PBAP are constant during their atmospheric residence time. However, several experimental studies have shown that PBAP undergo microphysical, chemical, and biological ageing processes in the atmosphere. These processes include bacterial agglomeration, modification of protein surfaces by chemical reactions (e.g., nitration) and cellular responses to changing ambient conditions. In addition, possible biological ageing processes such as cell growth and multiplication may change cell size and number. Here, we explore by means of process models the modification of the ice nucleating, hygroscopic and optical (scattering/absorption) properties of PBAP by such ageing processes with an emphasis on biological ageing. We show that cell growth/multiplication of ice-nucleating bacteria could enhance IN activity. Besides, cell modficaiton by ageing processes might change bacteria scattering properties due to size and surface composition modfication. Modification of protein surfaces  decreases IN activity for certain types of PBAP over atmospeherically relevant time scales. We perform model sensitivity tests over wide ranges of chemcial and biological parameters to identify conditions, under which these and other ageing processes have a significant effect on physicochemical properties of aged PBAP. Based on this analysis, we develop parameterizations for PBAP ageing processes to be included in aerosol and cloud models of different scales.
The role of extremity of summer floods for the annual statistic
Authors: Fischer Svenja , Schumann Andreas
Published: March 2020

Within the annual maximum series (AMS), which is the basis for assessing most of the flood protection measurements, summer as well as winter flood events are included. However, these do not only differ in their flood generation but also in their statistical distribution. While the distribution of winter floods is mostly light-tailed, summer floods often show a heavy-tailed behaviour. A light-tailed behaviour leads to a bounded distribution, which means that winter floods cannot exceed a certain magnitude. Heavy-tailed distributions are unbounded and extrapolation to annualities of several hundred years can lead to infinitely large design floods.  A combination of these different tail behaviours in the AMS often leads to heavy-tail behaviour for the annual series. In a study of the large river basins of Rhine, Danube and Elbe we investigate the impact of summer floods on the AMS. Spatial patterns become visible that can be linked to weather patterns like Vb. Moreover, an impact of the catchment size can be seen, where larger catchments tend to have lighter tailed distributions and a smaller impact of summer floods.  The results are then compared concerning their causality using deterministic models that include dam failure and inundation and the role of tributaries is shown.
Analysis of a new regional ionospheric assimilated H2PT model for Europe
Authors: Woźniak Paulina , Świątek Anna , Pożoga Mariusz , Tomasik Łukasz
Published: March 2020

The signal emitted by the GNSS (Global Navigation Satellite System) satellite, on the way to the receiver located on the Earth’s surface, encounters a heterogeneous layer of ionized gas and free electrons, in which the radio wave is dispersed. As the ionosphere is the source of the highest-value errors among the different factors that affect GNSS positioning accuracy, it is necessary to minimize its negative impact. Various methods are used to compensate for the ionospheric delay, one of which is the usage of models.
The intensity of the processes occurring in the ionosphere is closely related to the Sun activity. As a consequence, with respect to a given location on the Earth's surface, the activity of the ionosphere changes throughout the year and day. Therefore, a model dedicated to a specific region is especially important in case of high-precision GNSS applications.
The assimilated H2PT model was based on the dual-frequency observations from GNSS stations belonging to EPN (EUREF Permanent Network), as well as on ionosondes participating in the DIAS (European Digital Upper Atmosphere Server) project. The H2PT model covers the Europe area, data with a 15-minutes interval were placed in similar to IONEX (IONosphere Map EXchenge) files in two versions of spatial resolution: 1- and 5-degree. Data provided by the H2PT model are the VTEC (Vertical Total Electron Content) values and the hmF2 (maximum height of the F2 layer) parameters.
The subject of this research is the comparison of the H2PT model with NeQuick-G model and IONEX data published by IGS (International GNSS Service) in the context of TEC values as well as determining differences between regional hmF2 data and its commonly used fixed value for the entire globe, amounting to 450 km. In order to perform the analysis, appropriate visualizations were made and statistical parameters determined. Additionally, data from selected periods of positive and negative disturbances were analysed in details based on the developed time series.
The relatively high temporal and spatial resolution is undoubtedly an advantage of the H2PT model, because unlike global models, the regional one allows conscientious analysis of the ionosphere characteristics for the area of Europe. Importantly, solutions regarding hmF2 show significant deviations from the fixed value approximated for the whole Earth. Taking into account the parameter appropriate for a given location and time during GNSS data processing may improve the obtained positioning quality. 
Options and challenges for collaboration on climate service related activities at KNMI and KMI
Authors: Bessembinder Janette , De Troch Rozemien
Published: March 2020

National meteorological institutes have generally a longstanding scientific expertise in climate research, climatological observations, and state-of-the-art climate modelling. In the context of climate change this expertise and service provision of climatic data, information and knowledge is of crucial importance to meet the societal needs. Furthermore, in each country the provision of climate services is generally arranged differently and strongly determined by governance, the official strategy and tasks of the meteorological institutes, as well as financing.

To better align the activities between national climate service providers, the Royal Netherlands Meteorological Institute and the Royal Meteorological Institute of Belgium successfully applied for the ERA4CS action for the exchange of staff, aiming to contribute to the alignment of R&D programmes, tools/instruments and/or climate related agendas of both countries.

In the context of climate services, previous interactions between both institutes are mainly related to sporadically contacts between scientists in need of climatological data or information on methods for the definition of e.g. climate scenarios. However, Belgium and the Netherlands are neighbouring, both small countries, and climate change doesn’t stop at the border. Furthermore, coastal and inland regions along the borders are yet very sensitive to the impacts of climate change, and thus might cause cross-border issues in the future.

Therefore, a two-way visit of senior staff responsible for climate services in both institutes is planned for early 2020. The visits aim to identify the differences and similarities on how climate services are currently provided and the broader context in which climate services are developed and delivered (legal mandate, what other organisations deliver climate services, relation with policy e.g. National Adaptation Strategies). More specifically, the services related to both current and future climate conditions (i.e. climate scenarios), the respective impact sectors and users/stakeholders of the climate services and the interaction with them, the used tools and methods for the creation of climate services, and the outreach and communication strategies for climate services will be discussed through informal interactions, meetings and presentations.

An overview of these discussions together with conclusions on how climate-service related actions can be aligned and consolidated within future collaborations, will be presented.
Analysis and prediction of hydrological extreme conditions for a small headwater catchment in a German lower mountain range
Authors: Hennig Lisa , Frei Sven
Published: March 2020

Headwater catchments with wetlands represent important buffer areas by decreasing peak discharges and providing water in meteorological droughts. Wetlands act also as key feature of the riverine carbon cycle and are able to store significant amounts of carbon. Therefore, understanding and predicting discharge generating processes in the context of climate change is essential for such catchments. We use a Regional Climate Model (RCM) Ensemble to study possible changes in discharge patterns due to climate change at the Lehstenbach catchment, located in the Fichtelgebirge Mountains. Our aim is to quantitatively estimate periods of hydrological droughts and floods, their temporal length and intensity, their recurrence intervals as well as possible connections to snow melt. In order to achieve this goal, we use the process-based model HydroGeoSphere to simulate discharge until 2100 based on the RCM Ensemble. Statistical Analysis, including Trend and Wavelet Analysis aids us in detecting changing discharge conditions. Discharge seems to follow an increasingly variable pattern making droughts and floods more likely in the future. Since the overall length of drought conditions increases although precipitation amounts remain fairly stable, we identified evapotranspiration and altered precipitation patterns as main driving forces of droughts in this headwater. Snow conditions and subsequent spring floods seem to decrease in likelihood until 2100.
Linear and nonlinear waves in three-dimensional stratified rotating astrophysical flows in the Boussinesq approximation
Authors: Fedotova Maria , Petrosyan Arakel
Published: March 2020

Magnetohydrodynamic waves in a stratified rotating plasma in a gravitational field in the Boussinesq approximation are studied. The theory of flows on the f -plane, on the non-traditional f-plane (taking into account the horizontal component of the Coriolis force), on the beta -plane, and on the non-traditional beta -plane is developed. In each considered case linear solutions of systems of three-dimensional magnetohydrodynamic equations in the Boussinesq approximation are obtained in form of magnetic inertio-gravity waves, magnetostrophic waves, and magneto-Rossby waves. For equations of a rotating stratified plasma without taking into account sphericity (in the approximation of the f-plane and the non-traditional f- plane), dispersion relations describe three-dimensional magnetic inertio-gravity waves and three-dimensional magnetostrophic waves. In the case of propagating only along the vertical component of the wave vector, their dispersion relations describe two types of magnetic waves, the first of which is a special case of magnetic inerto-gravity waves propagating only vertically, and the second is a special case of magnetostrophic waves propagating only vertically. In addition, it was found that dispersion relations describing wave propagation taking into account sphericity in a first approximation (on the beta-plane and on the non-traditional beta- plane) along the vertical component of the wave vector have a similar particular form. In the case of wave propagation in a horizontal plane, magnetic inertio-gravity waves turn into Alfvén waves, and magnetostrophic waves turn into magnetogravitational waves. In addition, for waves on a non-traditional f-plane, the influence of the horizontal component of the Coriolis force on the existence of various types of three-wave interactions is shown. For equations of a rotating stratified plasma on the beta-plane and on the non-traditional beta-plane dispersion relations for horizontal waves are found in form of magnetogravitational waves (similar to waves on the f- plane) and various types of magneto-Rossby waves. In addition, the equivalence of the low-frequency mode of the magneto-Rossby wave in the Boussinesq approximation and in the magnetohydrodynamic shallow water approximation was shown. The dispersion curves of all the detected wave types are qualitatively analyzed to identify the fulfillment of the synchronism condition, which ensures the presence of three-wave interactions. A system of amplitude equations for interacting waves and the increments of two types of instability that occur in the system (decay and amplification) are obtained using the method of multiscale expansions. The difference in the coefficients and differential operators in the three-wave interaction system is shown for each of the found types of three-wave interactions.

This research was supported by the Russian Foundation for Basic Research (project no. 19-02-00016)
An unusual observation of a plasma structure in the mid-latitude ionosphere
Authors: Wood Alan , Dorrian Gareth , Fallows Richard
Published: March 2020

The LOFAR (Low Frequency Array) is one of the world’s leading radio telescopes, operating across the frequency band 10-250 MHz. As radio waves from astronomical sources pass through the ionosphere, they can undergo refraction and/or diffraction. The variations in the intensity of the received signal are caused by irregularities with a spatial scale size ranging from the Fresnel dimension to an order of magnitude below this value. The received signal can therefore be used to infer information on plasma structures in the ionosphere. As the frequencies used are significantly lower than the 1.4 GHz typically associated with Global Navigation Satellite Systems (GNSS), the plasma structures that affect the signals received by LOFAR are significantly larger, typically of the order of kilometres.

On 14th July 2018 the Dutch stations of LOFAR observed the strong natural radio sources Cassiopeia A and Cygnus A between 17:00 UT and 18:05 UT at a frequency range of 20-80 MHz. During the observation, the signal intensity received by many of the stations underwent a substantial reduction across all frequencies, lasting approximately 10 minutes. Immediately before and after this, periodic enhancements in the signal strength were observed. These enhancements showed a noticeable frequency dependence, with longer period oscillations at lower frequencies. The feature was not observed simultaneously by the stations and evolved during the observations. Such a feature is most likely to be the result of a large-scale density structure in the ionosphere, which appears to move west and north over the northern Netherlands.

The deep fading of the received signal may be due to the presence of sporadic-E, which is a consequence of variations in the neutral wind speed with altitude in the presence of the geomagnetic field, resulting in plasma accumulating in a thin layer. This can cause incident radio waves to be strongly refracted, affecting the strength of the received signal. The wave-like structure immediately before and after the deep fade is a likely consequence of scattering of the observed signal.
Complex, evolving patterns of mass loss from Antarctica’s largest glacier
Authors: Bamber Jonathan , Dawson Geoffrey
Published: March 2020

Pine Island Glacier (PIG) has contributed more to sea level rise over the last four decades than any other glacier in Antarctica. Model projections indicate that this will continue in the future but at conflicting rates, depending partly on the model initialisation. Some models suggest that mass loss could dramatically increase over the next few decades, resulting in a rapidly growing contribution to sea level, and fast retreat of the grounding line. Other models indicate more moderate losses. Resolving this contrasting behaviour is important for sea level rise projections as PIG and the Amndsen Sea Sector have been used as calibration for plausibility, probabilistic and deterministic approaches. Here, we use high resolution satellite observations of elevation change since 2010 from CryoSat-2 swath data to show that thinning rates are now highest along the slow-flow margins of the glacier and that the present-day amplitude and pattern of elevation change is inconsistent with fast grounding line migration and the associated rapid increase in mass loss over the next few decades. Instead, our results support model simulations that imply only modest changes in grounding line location over that timescale. We demonstrate how the pattern of thinning is evolving in complex ways both in space and time and how rates in the fast-flowing central trunk have decreased by about a factor five since 2007. We also consider how the complex pattern of mass loss affects the interpretation of vertical land motion from GPS data and inferences made from these data for mantle viscosity and solid Earth response times.

 
Vulnerability curves vs. vulnerability indices. Which method explains loss best?
Authors: Roesch Florian , Papathoma-Köhle Maria , Fuchs Sven
Published: March 2020

Mountain rivers are characterized by dynamic flooding with variable amounts of sediment erosion, deposition and remobilisation (Sturm et al., 2018); typical hazard processes include fluvial sediment transport, debris flows and related phenomena. In Europe, such processes repeatedly result in considerable damage to infrastructure and buildings on a local and regional level.

The physical vulnerability of buildings to dynamic flooding has been approached mainly with two methods until now: vulnerability curves and vulnerability indices. Each approach has its drawbacks and advantages (Papathoma-Köhle, 2016; Papathoma-Köhle et al., 2019). In the present study, damage data from a relatively recent event in the European Alps are used for the application of both methods. The event occurred in the municipality of See situated in the Paznaun valley in Tirol, Austria, in 2015. A new vulnerability curve is developed based on data from 21 buildings. An existing vulnerability index is also applied in the area. The results of both methods are compared with each other and with the actual loss of the event. Additionally, a sensitivity analysis regarding two input parameters (intensity and degree of loss) is performed for both the vulnerability curve and the vulnerability index. The results are mirrored against a recently developed vulnerability model for dynamic flooding in mountain areas (Fuchs et al., 2019), and possible model improvements are discussed.

 

References

Fuchs, S., Heiser, M., Schlögl, M., Zischg, A., Papathoma-Köhle, M., and Keiler, M.: Short communication: A model to predict flood loss in mountain areas, Environmental Modelling and Software, 117, 176-180, https://doi.org/10.1016/j.envsoft.2019.03.026, 2019.

Papathoma-Köhle, M.: Vulnerability curves vs. vulnerability indicators: application of an indicator-based methodology for debris-flow hazards, Natural Hazards and Earth System Sciences, 16, 1771-1790, https://doi.org/10.5194/nhess-16-1771-2016, 2016.

Papathoma-Köhle, M., Schlögl, M., and Fuchs, S.: Vulnerability indicators for natural hazards: an innovative selection and weighting approach, Scientific Reports, 9, Article 15026, https://doi.org/10.1038/s41598-019-50257-2, 2019.

Sturm, M., Gems, B., Keller, F., Mazzorana, B., Fuchs, S., Papathoma-Köhle, M., and Aufleger, M.: Experimental analyses of impact forces on buildings exposed to fluvial hazards, Journal of Hydrology, 565, 1-13, https://doi.org/10.1016/j.jhydrol.2018.07.070, 2018.
Mountain hazards and Building Back Better (BBB) – focus on the Austrian Alps
Authors: Ullrich Bernhard , Papathoma-Köhle Maria , Fuchs Sven
Published: March 2020

Natural hazards cause often material damages and loss of life. Human efforts are concentrated not only on the time preceding the occurrence of a hazard (forecast, evacuation, response, land use planning and structural measures) but also during (response, emergency operations) and after the occurrence of a catastrophic process (reconstruction of damaged buildings and infrastructure). As far as the reconstruction phase in concerned, authorities and citizens tend to rebuild their houses and infrastructure in the same way and location they were before the hazard strikes. The present study outlines the reconstruction efforts of two municipalities and the changes that they made following a torrential event in order to increase their resilience to natural hazards and to reduce future loss.  In more detail, a physical vulnerability index is used to assess the Build Back Better (BBB) of two alpine villages in Austria that experienced significant damages during the event of 2005. The BBB is investigated at three levels: the municipal level (structural measures and land use changes), the building level (physical vulnerability index) and the community level (public awareness). At the building level, the vulnerability index used is based on a number of indicators (building characteristics) including the height of windows, the existence, material and height of surrounding walls, the orientation of the building and the shielding of neighboring structures. The index compares the pattern of the physical vulnerability of buildings for both municipalities in 2005 and in the present. Both villages have now completed the reconstruction process, however, a similar event in the future could still cause significant damage. Changes in the building design and development of local adaptation measures have decreased the physical vulnerability of some buildings, however, some others remain equally vulnerable.  Based on the investigation of the reconstruction process recommendations regarding local adaptation measures are presented.
Development of a sampling protocol for the resource definition of sulphidic Cu-Zn-Pb tailings in an industrial tailings storage facility
Authors: Blannin Rosie , Frenzel Max , Tolosana-Delgado Raimon , Gutzmer Jens
Published: March 2020

Fine-grained residues of ore processing, known as tailings, are an inevitable product of metal production. Such tailings are typically stored in dedicated Tailings Storage Facilities (TSF). The sedimentary-style deposition of tailings within the TSF results in a structure of sub-horizontal, internally graded layers which heterogeneously concentrate the minerals comprising the residues. Primary depositional structures may be overprinted by subsequent chemical redistribution of minerals and elements during chemical reactions and metal mobilisation. Sulphidic tailings are problematic in terms of the potential for generation of Acid and Metalliferous Drainage, while providing interesting prospects for extraction of recoverable metals. However, efforts to build accurate and reproducible geospatial models of TSFs are hampered by a lack of understanding of how to sample heterogeneous tailings materials in a way that allows the effective characterisation of both the horizontal and vertical variability. This study introduces a sampling protocol for the resource characterisation of TSFs, following the Theory of Sampling. The Davidschacht TSF in Freiberg, Germany, was used as a case study. The Davidschacht TSF was deposited between 1944 and 1969; it contains around 760,000 m3 of Cu-Zn-Pb sulphidic flotation residues originating from the processing of polymetallic hydrothermal vein ores of the Freiberg mining district. A historical drilling campaign of 10 drill holes through the whole depth of the tailings provided a basis for the study. A second drilling campaign of 68 drill holes to a depth of 3 m was carried out on a 30 m grid, and nested grids of 15 m and 7.5 m in the centre of the TSF. The drill cores were logged and a bulk sample was collected for each 1 m section. Representative samples, with 10% randomly selected for duplication, will be analysed with X-Ray Fluorescence for chemical composition and sieving and laser diffraction for particle size distribution. The modal mineralogy, mineral associations and mineral liberation of selected samples will be assessed with the Scanning Electron Microscope-based Mineral Liberation Analyser. A detailed geospatial model of the surface zone of the tailings will be constructed to assess the intrinsic horizontal variability of the TSF. Comparison with the 3D model produced by the previous deep drilling campaign will determine if the sampling and modelling was sufficient to account for the variability of the tailings.
Mapping and comparing wildfire progressions using freely available, multi-source satellite data
Authors: Crowley Morgan , Cardille Jeffrey , White Joanne , Wulder Michael
Published: March 2020

Extreme wildfire seasons are becoming the new normal in Canada, and satellite imagery is a useful way to map these fires as they grow across the vast, fire-prone regions of the country. However, single-date and single-sourced imagery of active fires often contain clouds, flares, smoke, and haze that can create challenges for monitoring  burned areas over time. To address this gap, we applied rapid and scalable methods for synthesizing information on fire progressions using freely available satellite imagery, novel image fusion algorithms, and cloud-based data processing platforms. We identified images from Landsat-7, -8, Sentinel-2, and MODIS (MCD64A1 burned-area dataset) for the 2017 and 2018 British Columbia fire seasons that intersect the buffered extents of Canadian wildfires as determined by Canadian National Fire Database. We classified each raw image individually using a standard burned-area classification protocol related to each data source. We used the Bayesian Updating of Land Cover Classifications (BULC) algorithm to create coherent time series from the single-date classifications of optical data sources in Google Earth Engine. From the BULC classification stack, we calculated within-year, intra-annual fire progression metrics to compare satellite-derived fire behaviours between the 2017 and 2018 fire seasons, both at the whole fire season and the individual fire level. End-of-season burned-area estimates corresponded with estimates derived from the National Burned Area Composite (NBAC) product that is generated retrospectively from best-available fire mapping approaches. Additionally, we compared the BULC time series with fire progression estimates from MCD64A1 burned-area dataset to evaluate the influence of spatial resolution on burned-area estimates. Information outputs from this research enable cross-validation of fire behaviour models for different fire seasons and comparison of fire progression metrics between historic fires and fire seasons in Canada. The approach presented can be used to provide rapid and reliable information about active wildland fire progressions to better understand fire growth and associated drivers.
North Hemispheric winter air temperature variability and its linkage to North Pacific and North Atlantic SST modes?
Authors: Luo Binhe , Luo Dehai , Dai Aiguo , Wu Lixin
Published: March 2020

Winter surface air temperature (SAT) over North America exhibits pronounced variability on sub-seasonal-to-interdecadal timescales, but its causes are not fully understood. Here observational and reanalysis data from 1950-2017 are analyzed to investigate these causes. Detrended daily SAT data reveals a known warm-west/cold-east (WWCE) dipole over midlatitude North America and a cold-north/warm-south (CNWS) dipole over eastern North America. It is found that while the North Pacific blocking (PB) is important for the WWCE and CNWS dipoles, they also depend on the phase of the North Atlantic Oscillation (NAO). When a negative-phase NAO (NAO-) concurs with PB, the WWCE dipole is enhanced (compared with the PB alone case) and it also leads to a warm north/cold south dipole anomaly in eastern North America; but when PB occurs with a positive-phase NAO (NAO+), the WWCE dipole weakens and the CNWS dipole is enhanced. In particular, the WWCE dipole is favored by a combination of eastward-displaced PB and NAO- that form a negative Arctic Oscillation. Furthermore, a WWCE dipole can form over midlatitude North America when PB occurs together with southward-displaced NAO+.The PB events concurring with NAO- (NAO+) and SAT WWCE (CNWS) dipole are favored by the El Nio-like (La Nia-like) SST mode, though related to the North Atlantic warm-cold-warm (cold-warm-cold) SST tripole pattern. It is also found that the North Pacific mode tends to enhance the WWCE SAT dipole through increasing PB-NAO- events and producing the WWCE SAT dipole component related to the PB-NAO+ events because the PB and NAO+ form a more zonal wave train in this case.