bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatiotemporal Variability of Snow Depth in Subarctic Environment Using Unmanned Aircraft Systems (UAS)
Authors: Rauhala Anssi , Meriö Leo-Juhani , Ala-aho Pertti , Korpelainen Pasi , Kuzmin Anton , Kumpula Timo , Heikkilä Rauno , Kløve Bjørn , Marttila Hannu
Published: March 2020

Seasonal snow accumulation and melt dominates the hydrology in high latitude areas, providing water storages for both ecological and human needs. However, until recent years there has been a lack of cost-efficient way to measure the spatiotemporal variability of the snow depth and cover in high resolution. Unmanned aircraft systems (UAS) can offer spatial resolutions up to few centimeters, depending on the weather and light conditions, camera quality and drone specification. We used multiple different quadcopters and a fixed wing UAS to determine and analyze the spatiotemporal variability of snow depth and cover in three test plots with different land-cover types (forested slope, open peatland, and peatland-forest) in subarctic northern Finland, where weather and light conditions are challenging. Five measurement campaigns were conducted during winter 2018/2019 and a snow-free bare ground survey after snowmelt. Snow depth maps were constructed using Structure from Motion (SfM) photogrammetry technique and by differentiating the acquired models from snow-covered and snow-free surveys. Due to poor sub-canopy penetration with UAS-SfM method, tree masks were utilized to remove canopy effects prior to analysis. The snow depth maps produced with different UAS were compared to in situ snow course and an automatic ultrasonic measurement data. We highlight the difficulties of working in subarctic winter conditions and discuss the accuracy of UAS-derived snow depth maps. We show that the UAS-derived snow depth measurements agree well with manual snow survey measurements and UAS are suitable method for extending the spatial snow data coverage, whereas a continuous point snow depth measurement is unable to accurately present sub-catchment scale snow depth variability. Furthermore, the spatiotemporal variability of snow accumulation and melt between and within different land cover types is presented.
The sensitivity of ice-nucleating minerals to heat and implications for the detection of biogenic ice-nucleating particles
Authors: Daily Martin Ian , Whale Thomas Francis , Murray Benjamin John
Published: March 2020

Ice nucleating particles (INP) are a subset of atmospheric aerosols which strongly influence the radiative properties and precipitation onset in mixed phase clouds. Mineral dust and biogenic particles such as bacteria, pollen and fungal spores can act as INP and are present in the atmosphere as internal or external mixtures. However, the sources, abundance and distribution of INP are poorly understood. The current widely accepted method of determining the relative contributions of mineral and biogenic INP is to treat INP samples with heat. This is based on the hypothesis that proteinaceous biogenic INP will be deactivated and mineral INP will be unaffected. However the hypothesis that mineral INP are never deactivated by heating not been tested to date. Mineral surfaces may undergo a range of geochemical reactions when heated in air or water and the potential effects of this on their ice nucleating activity is not known. We therefore subjected a range of atmospherically relevant minerals and atmospheric dust analogues to heat treatments equivalent to those used in the past studies. The samples were heated both as aqueous suspensions (100°C for 30 minutes) and in air as dry powders (250°C for 4 hours) and their ice nucleating activity was tested before and after treatment with a microlitre droplet freezing assay. We found that silica based samples showed a significant response to aqueous heating (reduction of median freezing temperature of a 1% suspension of up to 5.4°C) but little response to dry heating. Similar responses were seen in Arizona Test Dust and calcite. In contrast, K-feldspar samples were largely unaffected by aqueous heating but some showed mild deactivations when dry heated. Notably, K-feldspar was sensitive to longer heat treatments. Overall this survey shows that the assumption that mineral INP are completely inert to heat should be reconsidered in the context of using heat to ‘detect’ biogenic INP. We conclude that while INP heat tests are an effective method for positive detection of biogenic INP in ambient air samples they have the potential to produce false positives. For example, in a silica-rich mineral dust a deactivation may be related to the mineral component. Nevertheless, in samples where the mineral ice nucleating activity is determined by K-feldspar the aqueous heat test provides a valid qualitative test for proteinaceous biological INP.
Improved parameterization of airborne electromagnetic surveys for groundwater salinity mapping using 3D variable-density groundwater flow models
Authors: King Jude A. , Essink Gualbert H. P. Oude , Bierkens Marc F. P.
Published: March 2020

Airborne electromagnetics is a cost-effective and rapid method with which to map the regional distribution of saline groundwater in coastal areas, however the process of transforming observed data into salinity estimates comprises multiple sources of uncertainty. The resulting error primarily relates to two factors: (1) the transformation (or inversion) from airborne observations into physical properties, (2) the availability of lithological information to transform inversion results to salinity estimates. Recent research has shown that this uncertainty can significantly affect the accuracy of resulting groundwater salinity estimates, in particular the location of the fresh-saline interface. Reducing error relating to the two factors is not trivial. Firstly, as the inversion process is non-unique, an infinite number of models can fit the data. Secondly, the availability of lithological information on regional scales is generally low. To highlight potential sources of error and improve parameterization, we investigate the usefulness of combining airborne electromagnetic data with a 3D variable-density groundwater flow and coupled salt transport model. We quantitatively present findings using a synthetic model which was created using an existing large-scale (~100km2) 3D groundwater model based on real data from the Netherlands. The model is created in two steps: (1) the available groundwater model is run until a state of equilibrium is reached with the model boundaries and stress terms and (2), an airborne survey is simulated using standard geophysical forward modelling techniques, resulting in set of observations. The airborne observations are then inverted and used alongside a simulated lithological data acquisition programme, which are finally input as initial conditions to a groundwater model. As the groundwater model is assumed to be in a state of equilibrium, we show the effect of implementing an optimization framework that penalizes the rate of groundwater salinity fluctuations by iteratively changing the input parameters of both the inversion method and the lithological data. Results quantitatively highlight the effectiveness of implementing a simple, inter-disciplinary approach to airborne electromagnetic groundwater mapping.
Constraining Mantle Source Conditions at Iceland and Adjoining Ridges Using Markov Chain Monte Carlo Inversion
Authors: Brown Eric , Lesher Charles
Published: March 2020

Basalts are generated by adiabatic decompression melting of the upper mantle, and thus provide spatial and temporal records of the thermal, compositional, and dynamical conditions of their source regions. Uniquely constraining these factors through the lens of melting is challenging given the complexity of the melting process. To limit the a priori assumptions typically required for forward modeling of mantle melting, and to assess the robustness of the modeling results, we combine a Markov chain Monte Carlo sampling method with the forward melting model REEBOX PRO [1] simulating adiabatic decompression melting of lithologically heterogeneous mantle. Using this method, we invert for mantle potential temperature (Tp), lithologic trace element and isotopic composition and abundance, and melt productivity together with a robust evaluation of the uncertainty in these system properties. We have applied this new methodology to constrain melting beneath the Reykjanes Peninsula (RP) of Iceland [2] and here extend the approach to Iceland’s Northern Volcanic Zone (NVZ). We consider melting of a heterogeneous mantle source involving depleted peridotite and pyroxenite lithologies, e.g., KG1, MIX1G and G2 pyroxenites. Best-ﬁt model sources for Iceland basalts contain more than 90% depleted peridotite and less than 10% pyroxenite with Tp ~125-200 °C above ambient mantle. The trace element and Pb and Nd isotope composition of the depleted source beneath the Reykjanes Peninsula is similar to DMM [3], whereas depleted mantle for the NVZ is isotopically distinct and more trace element enriched. Conversely, inverted pyroxenite trace element compositions are similar for RP and NVZ and are more enriched than previously inferred, despite marked differences in their Pb and Nd isotope composition. We use these new constraints on the Iceland source to investigate their relative importance in basalt genesis along the adjoining Reykjanes and Kolbeinsey Ridges. We find that the proportion of pyroxenite diminishes southward along Reykjanes Ridge and is seemingly absent to the north along the Kolbeinsey Ridge. Moreover, abundances of inverted RP and NVZ depleted mantle also diminish away from Iceland and give way to a common depleted source for the North Atlantic. These findings further illuminate the along-strike variability in source composition along the North Atlantic ridge system influenced by the Iceland melting anomaly, while reconciling geochemical, geophysical and petrologic constraints required to rigorously test plume vs. non-plume models.

[1] Brown & Lesher (2016); G^3, v. 17, p. 3929-2968

[2] Brown et al. (2020); EPSL, v. 532, 116007

[3] Workman and Hart (2005); EPSL, v.231, p. 53-72
The syn- and post-obduction history of the offshore north Oman margin
Authors: Ninkabou Dia , Agard Philippe , Nielsen Charlotte , Smit Jeroen , Haq Bilal , Rodriguez Mathieu , Gorini Christian
Published: March 2020

The offshore north Oman margin, located north of the Hajar Mountains in the Gulf of Oman,
remains a key area for understanding the evolution of the obduction Emails Ophiolite. With the
help of a grid of 2D-multichannel seismic lines linked to well data, we present a new view of
the obduction and post-obduction history of the Oman margin. Offshore deposits, overlying on
what we interpret as being the offshore extension of the ophiolites, can be divided into two
mega-sequences. The older one is comprised of late Cretaceous to Paleogene deposits mainly
located in the Sohar basin and offshore of the Abat trough. In the Sohar basin, the latest stages
of obduction are recorded by the deposition of the erosional products of the Autochthonous
Arabian sediments and the ophiolite, in a flexural basin induced by a volcanic high. Offshore
of the Abat trough, a Maastrichtian-Paleocene basin develops above a detachment fault
system linked to the extension phase associated to the exhumation/expulsion of the subducted
continental margin. Both sectors are divided by a structured high located offshore of the Semail
Gap transfer fault. We propose that this transfer fault, likely a major Pan-African structure,
impacted both the architecture of the passive margin following the rifting of the Neotethys and
later ophiolite emplacement, during (continental) subduction and obduction.
Reduced stochastic aggregation of convection conditioned by large scale dynamics in the atmosphere
Authors: Polzin Robert Malte , Müller Annette , Nevir Peter , Rust Henning , Koltai Peter
Published: March 2020

The presented work contains an investigation of the stochastic aggregation of convective structures on different scales in the atmosphere. A
computational framework is applied that provides highly scalable identification of reduced Bayesian models. The deterministic large scale
flow variables are reduced into latent states, whereas the stochastic small scale convective structures are affiliated to these. The analysis of
the latent states in number and maximization reduction improves the understanding for the large scale forcing of convective processes. The
convective structures are determined by vertical velocities. Different variables of the large-scale flow, such as the convective available
potential energy, available moisture, vertical windshear and the Dynamic State Index (DSI), a diabaticity indicator, are investigated. Our approach
does not require a distributional assumption but works instead with a discretised and categorised state vector.
High resolution multi-viewpoint observations of CME kinematics and dynamics
Authors: Mrotzek Niclas , Bothmer Volker
Published: March 2020

Coronal mass ejections (CMEs) are impulsive outbursts of coronal plasma bound in magnetic structures. Their initiation and evolution into the heliosphere covers several orders of magnitude of temporal and spatial scales that can be observed with space-borne extreme ultraviolet imagers, coronagraphs and heliospheric imagers. In this work we present a systematic investigation of the early dynamics of CMEs including their kinematics, orientation and geometrical evolution. For this purpose, a dedicated set of 21 Earth-directed CMEs between July 2011 and November 2012 was selected and analyzed. The CME parametrization is obtained by applying a 3D modelling method, the Graduated Cylindrical Shell (GCS) model, to simultaneous multi-viewpoint observations taken with the SECCHI instrument suite onboard the twin STEREO spacecraft and with the LASCO coronagraphs onboard the SOHO satellite. By using these instruments, the CME dynamics including the kinematics and geometry, are covered in high detail over a wide spatial range. For the majority of events it started in the field of view of EUVI below 2 solar radii and extended into the field of view of HI1 up to 100 solar radii. The results reveal interactions of the CMEs with the ambient solar wind. CME deflections of up to 31° in longitude and 18° in latitude were measured within the first 30 solar radii. Furthermore, evidence of CME oscillations with periods between 29 and 93 minutes were found. The analysis provides important implications for more reliable space weather forecasts and further analysis through the new observations from Parker Solar Probe and Solar Orbiter.

 
Catalyzing innovation: governance enablers of nature-based solution success stories
Authors: Martin Juliette Genevieve Crescentia , Linnerooth-Bayer JoAnne , Scolobig Anna , Liu Wei
Published: March 2020

There is growing recognition that using the properties of nature can help provide viable and cost-effective solutions to a wide range of societal challenges, including disaster risk reduction. However, nature-based solution (NBS) realization depends critically on the legal, institutional, social, political and financial conditions – that is, the governance framework - that enable the NBS policy process. Drawing from three case studies in Nocera Inferiore (Italy), Munich (Germany) and Wolong (China), we identify key governance enablers of successful NBS - that is, the contextual pre-conditions, policy processes and institutions that proved helpful or even essential for the initiation, planning, design and implementation of NBS. Results show that the most critical enablers involved governance innovation in three areas: polycentric governance (novel arrangements in the public administration that involved multiple institutional scales and/or sectors), NBS co-design (innovative stakeholder participatory processes that influenced the final NBS) and financial incentives (financial incentives for community-based implementation and monitoring of NBS). Further enablers for realizing NBS, as demonstrated in the three cases, include environmental advocacy coalition groups, along with their individual champions, and a major triggering or modelled event, which opened a window of opportunity to advocate for a nature-based or hybrid green-blue-grey solution. Findings show that the transition from grey solutions to NBS can be justified with, and contribute to, multiple global agendas and targets, including disaster risk reduction, climate change adaptation, halting biodiversity loss and sustainable development.
Meso- and micro-structural analysis of the Briançonnais Front in the Grand Saint Bernard area (Aosta Valley - Italy, and Valais - Switzerland)
Authors: Pini Daniele , Arienti Gloria , Pozzi Matteo , Monopoli Bruno , Bistacchi Andrea
Published: March 2020

We present preliminary results on the meso- and micro-structural evolution of high-strain rocks of the Houillère Zone and Pierre-Avoi Unit outcropping along the Swiss-Italy boundary ridge, to the west of the Grand Saint Bernard Pass.

The stack of Middle and External Pennidic units is folded by polyphasic folds, developed at least partly under low-grade metamorphic conditions. Different generations of folds show isoclinal to open geometries. Fold axes are subhorizontal, trending NE-SW, and the overall fold interference pattern can be generally classified as a type 3 (Ramsay). At the microscale, an important deformation mechanism is pressure solution cleavage, consistent with relatively low-temperature conditions.

Brittle-ductile shear zones, characterized by anastomosing bands of very fine-grained fault rocks, with pressure solution seams and SCC’ shear bands, exploit the weak and strongly anisotropic phyllosilicate-rich layers, particularly in the black schists of the Houillère Zone.

Brittle high-angle faults crosscut ductile and semi-brittle features and show an oblique-normal kinematics. These faults are particularly well developed in the more competent rocks of the Pierre-Avoi Unit (e.g. massive carbonates, metaconglomerates and metasandstones).

A continuous horizon, a few metres thick, with a high density of quartz veins, can be followed in the internal and upper part of the Houillère Zone. This horizon is folded, at least by the younger open folds, and constitutes a major marker to study the large-scale structure of this unit.
Snow observations in Finland in support of designing nature-based solutions – from citizen observations to satellites
Authors: Drebs Achim , Jantunen Reijo , Mäkelä Antti , Tuomenvirta Heikki
Published: March 2020

As a representative example of an inland water system in northern Europe the Lake Puruvesi tends to suffer from nutrient and loads. Surface runoff caused by extreme precipitation or excessive, rapid snow melt produce nutrient leaching especially from heavily managed forests. Citizen science has potential to address to risk of eutrophication of Lake Puruvesi. Firstly, forest owners need to be engaged to the project to co-design and co-develop nature-based solutions including information about forest management options to reduce nutrient leaching. Secondly, to improve understanding and modelling  standard observational network should be enhanced. The extreme precipitation in the area is monitored throughout the year with, in particular, for this project established automatic precipitation station. Additionally, during the winter season a group of citizen volunteers measure manually snow depth and snow density in the catchment area of Lake Puruvesi. The precipitation and snow data collected with in-situ and satellite measurements are analyzed to indicate the relationships of the nutrient flows and precipitation in the area. Here we present the preliminary results from the measurement campaign from the period January-April 2020.
PyTrx: a Python-based monoscopic terrestrial photogrammetry toolset for glaciology
Authors: How Penelope , Hulton Nicholas , Buie Lynne , Benn Douglas
Published: March 2020

Terrestrial photogrammetry is a growing method for deriving measurements from contemporary and historical imagery of glacial environments, providing unique insights into glacier change at a high spatio-temporal resolution. However, the potential usefulness of terrestrial image data is currently limited by the unavailability of user-friendly toolsets that contain all the photogrammetry processes required. PyTrx is presented here as a Python-alternative toolset to widen the range of monoscopic photogrammetry (i.e. from a single viewpoint) toolsets on offer to the glaciology community. The toolset holds core photogrammetric functions for template generation, feature-tracking, object identification, image registration, and georectification (using a planar projective transformation model), which can be performed on both contemporary and historical imagery. Examples of PyTrx's applications are demonstrated using contemporary time-lapse imagery, including ice flow velocities, surface areas of supraglacial lakes and meltwater plumes, and glacier terminus profiles.
Combining water engineering and landscape architecture practices for multifunctional and robust design of Nature-Based Solutions
Authors: Zhong Lei , Zoran Vojinovic Zoran Vojinovic , Francac Mário
Published: March 2020

Hydro-meteorological disasters have shown the fastest rate among all natural disasters. This is due to several factors: i) climate change, ii) population growth and land use change, and iii) poor water management practices. Traditional engineering solutions have shown to be ineffective in responding to such challenges and hydro-meteorological risks in general. In this respect, Nature-Based Solutions (NBS) offer the means to respond to such increasing challenges by providing a range of benefits (i.e., hydro-meteorological risk reduction) and co-benefits (i.e., ecosystems restoration and increase socio-economic values). The need to incorporate numerous benefits and co-benefits into the design of NBS calls for a combination of knowledges and practices from water engineering and landscape architecture. These would be necessary to design an NBS site that have multiple functions that can incorporate multiple benefits and co-benefits. At the same time, NBS should be designed in such way to withstand possible changes and pressures. This in turn calls for novel design practices of NBS to support planning and implementation that can achieve multifunctional and robust results. In this work, a framework for multifunctional and robust design of NBS is addressed. This framework will combine the use of hydrodynamic models, GIS tools, topology analysis, adaptive options analysis, adaptive pathway design, multi-criteria analysis, cost-benefit analysis, and robustness evaluation. The framework will be applied to one of the RECONECT cases and the first results will be presented.
Analysis of THCM coupling in heterogeneous sediments using high-pressure flow-through testing systems
Authors: Deusner Christian , Gupta Shubhangi , Falenty Andrzej , Kossel Elke , Haeckel Matthias
Published: March 2020

The experimental and numerical investigation of THCM process coupling is important to better understand reservoir geotechnical behavior and sub-surface processes. In particular, when THCM process coupling is dominated by focused fluid migration and localized chemical or microbiological reactions, bulk sediment and, thus, reservoir geotechnical behavior becomes poorly predictable. To improve the understanding of these complicated processes and process coupling on relevant time and spatial scales, it is necessary to combine experimental and numerical simulation approaches, and to develop complementary investigation strategies.    

We use different high-pressure flow-through experimental systems with triaxial testing units in combination with tomographical imaging tools (e.g. X-ray CT and ERT) to simulate and analyze relevant processes in ocean and earth systems. Our geotechnical studies are carried out at high hydrostatic pressures up to 40 MPa and temperatures between -30°C and 80°C. The experimental systems allow testing of large sample specimen (up to a diameter of 150 mm and a height of 400 mm). In particular, we investigate scenarios with heterogeneous phase distributions and dynamic flow conditions, which cannot be interpreted based on the assumption of homogeneous phase distributions in a sensible manner.

Here, we focus on discussing experimental and numerical strategies and problems towards understanding geotechnical behavior of heterogeneous sediments, including issues from gas migration in fine-grained sediments (e.g. silty clays), gas hydrate formation under two-phase flow conditions, and localized failure and shear banding in cemented soils. We present results from recent studies on underground usage including gas production and injection scenarios, which are relevant for the understanding of reservoir behavior, storage scenarios and, overall, marine sediment and slope stability. One of the most important aspects is to improve current strategies for combined and complementary experimental and numerical studies, considering that the overall objective is to understand processes on a reservoir scale.
Geohazard assessment of mass movements along railroad corridors with UAV LiDAR
Authors: Delparte Donna , Lifton Zachery , Belt Matthew
Published: March 2020

Railroad corridors in northern Idaho are subject to landslides, debris flows, and rock fall. These geologic hazards have the potential to severely impact railroad assets, profitability, and public safety, particularly when hazardous materials are transported. Recent slope instability and mass movement in these railroad corridors have affected rail operations and emphasized the need for a detailed understanding of geologic hazards and slope dynamics in this region. Idaho Geological Survey (IGS) and Idaho State University (ISU) conducted a series of Unmanned Aircraft Systems (UAS) missions equipped with LiDAR to survey selected landslides. This pilot project acquired high-resolution data at two sites along steep canyon slopes of the Kootenay River and one site along the Moyie River. The selected sites represent a diversity of terrain conditions, coverage area, forest canopy, and mass movement activity. In addition to collecting bare earth models of the landslide areas, this pilot project assessed resolution requirements, canopy penetration, and deployment complexity to provide a baseline for repeat surveys. Best practices for data collection and point cloud alignment for geohazard assessment are highlighted based on variations in terrain cover and slope.
Deep Learning-based Surrogate Models for Water Distribution Systems
Authors: Taormina Riccardo , Ashrafi Mohammad , Murillo Andres , Galelli Stefano
Published: March 2020

Simulation-based optimization is widely used for designing and managing water distribution networks. The process involves the use of accurate computational models, such as EPANET, which represent the physical processes taking place in the water network and reproduce the control logic governing its operations. Unfortunately, running such models requires expensive computations, which, in turn, may hinder the application of simulation-based optimization to large and complex problems. This issue can be overcome by resorting to surrogate models, that is, simplified data-driven models that accurately mimic the behaviours of physical-based models at a fraction of the computational costs. In this work, we explore the potential of Deep Learning Neural Networks (DLNN) for building surrogate models for water distribution systems. Different DLNN architectures, including feed-forward and recurrent neural networks, are trained and validated on datasets generated through EPANET simulations. The DLNN models are then used in lieu of the original EPANET model to speed-up the evaluation of the objective function employed in a simulation-based optimization problem. The effectiveness of the proposed technique is assessed on a realistic case-study involving cyber-attacks on a water network. In particular, the DLNN surrogate models are employed by an evolutionary optimization algorithm that schedules the operations of hydraulic actuators in order to best respond to the attacks and facilitate the recovery process.
Electrical imaging of the Mohns Ridge in the Greenland Sea
Authors: Johansen Ståle , Panzner Martin , Mittet Rune , Amundsen Hans , Lim Anna , Vik Eirik , Landrø Martin , Arntsen Børge
Published: March 2020

A detailed 120 km deep electromagnetic joint inversion model for the ultra-slow Mohns Ridge was constructed combining controlled source- and magnetotelluric data. About one third of mid-ocean ridges have a spreading rate less than 20 mm/yr1, but due to lack of deep imaging, factors controlling melting and mantle upwelling, depth to the lithosphere – asthenosphere boundary (LAB), crustal thickness and hydrothermal venting are not well understood for this class of ridges. Modern electromagnetic data have significantly improved understanding of fast-spreading ridges, but have not been available for the ultra-slow ridges. The new inversion images show mantle upwelling focused along a narrow, oblique and strongly asymmetric zone coinciding with asymmetric surface uplift. Though the upwelling pattern shows several of the characteristics of a dynamic system, instead it likely reflects passive upwelling controlled by slow and asymmetric plate movements.

Upwelling asthenosphere and melt are enveloped by the 100 Ωm contour denoted the electrical LAB (eLAB). This transition may represent a rheological boundary defined by a minimum melt content. We also find that a model where crustal thickness is directly controlled by the melt-producing rock volumes created by the separating plates can explain the thin crust below the ridge. Fluid convection extends for long lateral distances exploiting high porosity at mid crustal levels. The magnitude and long-lived nature of such plumbing systems could promote venting at ultra-slow ridges. Further, active melt emplacement into ca 3 km thick oceanic crust culminates in an inferred crustal magma chamber draped by fluid convection cells emanating at Loki´s Castle hydrothermal field.
Federated and intelligent datacubes
Authors: Atherton Chris , Löwe Peter , Heinen Torsten
Published: March 2020

We face unprecedented environmental challenges as a species, that threaten our existing way of life.  We are still learning to understand our planet, although we have a good idea how it works.  The speed of research needs to accelerate to provide information to decision makers, to better respond to our societal challenges.  To do this we need to move towards leveraging large datasets to speed up research, as proposed by Jim Grey in ‘The Fourth Paradigm’. In the world of research infrastructures we need to provide a means for scientists to access vast amounts of research data from multiple data sources in an easy and efficient way.  EOSC is addressing this but we are only scratching the surface when it comes to unleashing the full potential of the scientific community.  Datacubes have recently emerged as a technology in the Environmental and Earth system domain to store imagery data in a way that makes it easier and quicker for scientists to perform their research.  But with the scales of data volumes that are being considered, there are many challenges to curating, hosting, and funding this information in a centralised centre.  Our proposal seeks to leverage the existing National Research and Education (NRENs) infrastructures to store national repositories of regional Environmental and Earth system domain data, for this to be shared with scientists in an open, federated but secure way, conforming to FAIR principles.  This would provide levels of redundancy, data sovereignty and scalability for hosting global environmental datasets in an exascale world.
Global Analysis of Marine Heatwave physical Processes
Authors: Darmaraki Sofia , Oliver Eric
Published: March 2020

Marine heatwaves (MHWs) are periods of extreme warm temperatures in the ocean and have been seen to exert substantial pressure to marine ecosystems around the world. For instance, they may drive widespread marine species die-offs, force coastal marine ecosystem regime shifts, promote toxic algal blooms, and/or alter the distribution of commercial fisheries on a scale of weeks to months. Recent studies have indicated a significant increase in MHW frequency and intensity throughout the 20th century, a trend which is likely to aggravate in the 21st century, according to future projections.  Therefore, it is crucial to understand what are the climate drivers and physical processes governing MHWs in different regions of the global ocean and how these may change under the climate change regime. Here, we perform a mixed layer heat budget analysis, using a global ocean reanalysis product, to diagnose the relative role of ocean advection and atmosphere fluxes on the development of past MHWs around the world. Significant events are first identified using a consistent framework. Then, the heat budget results reveal that certain physical processes tend to be dominant in different regions, which can be traced back to specific local-scale dynamics. The global scale of this analysis provides a significant addition to the current literature which has, so far, been focused on the examination of the underlying mechanisms behind individual events. It also contributes to a better understanding of the variability and processes governing MHWs, offering also a potential ability for future event predictability.
Surface sealed light weight aggregate from mine tailings
Authors: Oye Bjarte , Hoyli Randulf , Danielsen Svein Willy
Published: March 2020

Traditionally manufactured light-weight aggregates (LWA) suffer from a fractured surface. Consequently, concrete mixes containing LWA cannot be pumped, due to the water being forced into the porous LWA pellets by the pumping pressure. This is a limitation and a cost factor in construction practise. As part of the project "Nye produkter fra gruveavfall i nord" (Novel products from mine tailings in Northern Norway), will examine mine tailings aiming to develop new products. A pilot study has aimed to develop high quality LWA suitable for pumping from Nussir mining company tailings. In 2019, Nussir ASA was granted operational licence for exploitation of the Repparfjord copper deposit in northern Norway. The tailings, 30 Mtons in total and 1-2 Mtons per year, is deposited in sea.

LWA is traditionally made from pelletized clays, where (Na, K, Mg, Ca, Fe)-aluminosilicates are heated to a viscous glassy phase and subsequently bloated by carbothermal reduction of Fe(III)-oxide, developing carbon monoxide gas inside the pellets. The pellets are then quenched in air, and this is the stage where the surface is fractured. In the pilot study, mine tailings lower in sodium and potassium have been identified, aiming to increase the thermal shock resistance enabling a non-fractured pellets surface. Experimental work was carried out by placing the pellets in a preheated furnace, subsequently quenching pellets at different predetermined times. the results from the study showed that it was possible to produce an unfractured surface, but work is still needed to optimise the bloating. The pellets had an optimal bloating temperature of 1225 °C which is almost 100 °C higher than for typical clay LWAs. Exposure time was ca 5 minutes, a bit shorter than traditional LWAs. The main project will continue the work with a series of new tailings, varying in both composition and particle size.
Using Ship-Deployed High-Endurance Unmanned Aerial Vehicles for the Study of Ocean Surface and Atmospheric Boundary Layer Processes
Authors: Brown Scott M. , Zappa Christopher J. , Laxague Nathan J. M. , Dhakal Tejendra , Harris Ryan A. , Farber Aaron , Subramaniam Ajit
Published: March 2020

Unmanned aerial vehicles (UAVs) are proving to be an important modern sensing platform that supplement the sensing capabilities from platforms such as satellites, aircraft, research vessels, moorings, and gliders. UAVs, like satellites and aircraft can provide a synoptic view of a relatively large area. However, the coarse resolution provided by satellites and the operational limitations of manned aircraft has motivated the development of unmanned systems. UAVs offer unparalleled flexibility of tasking; for example, low altitude flight and slow airspeed allow for the characterization of a wide variety of geophysical phenomena at the ocean surface and in the marine atmospheric boundary layer. Here, we present the development of cutting-edge payload instrumentation for UAVs that provides a new capability for ship-deployed operations to capture a unique, high resolution spatial and temporal variability of the changing air-sea interaction processes than was previously possible. The modular design of the base payload means that new instruments can be incorporated into new research proposals that may include new instruments for expanded use of the payloads as a long-term research facility. Additionally, we implement a novel capability for vertical take-off and landing (VTOL) from research vessels. This VTOL capability is safer and requires less logistical support than previous ship-deployed systems. Furthermore, these VTOL UAV systems have 15-hour endurance with 15-lb payloads, fully autonomous take-off, flight, and landing from ships, and high-bandwidth data telemetry (100 Mbits/s over 50+ nm range) for real-time mission control and provide for our “eyes over the horizon.” The payloads developed include thermal infrared, visible broadband and hyperspectral, and near-infrared hyperspectral high-resolution imaging. Additional capabilities include quantification of the longwave and shortwave hemispheric radiation budget (up- and down-welling) as well as direct air-sea turbulent fluxes. Finally, a UAV-deployed dropsonde-microbuoy was developed in order to profile the temperature, pressure and humidity of the atmosphere and the temperature and salinity of the near-surface ocean. These technological advancements provide the next generation of instrumentation capability for UAVs. We present on the results of 3 case studies in the South Pacific near Fiji, including measurements characterizing meso-scale ocean SST fronts, trichodesmium blooms, and floating pumice rafts from a recent undersea volcanic eruption near Tonga. When deployed from research vessels, these UAVs will provide a transformational science prism unequaled using 1-D data snapshots from ships or moorings alone.
Commercial wheat fertilization based on nitrogen nutrition index and yield forecast
Authors: Plaza Carmen , Calera María , Campoy Jaime , Osann Anna , Calera Alfonso , Bodas Vicente
Published: March 2020

This work describes the practical application on commercial wheat plots of the methodology developed and evaluated in Albacete, Spain, in the framework of the project FATIMA (http://fatima-h2020.eu/). The application considers two different methodologies for the prescription of nitrogen management prior to the flowering season, based on the diagnosis of crop nitrogen status based on nitrogen nutrition index (NNI) maps and the yield forecast spatially distributed. The NNI is the ratio between the actual nitrogen concentration (Na) over the critical nitrogen concentration (Nc) for the crop analysed (Justes et al 1997). The nitrogen uptake was determined from relationship between Nc and biomass, where biomass was estimated by a crop growth model based on the water productivity. The Na was derived from the relationship between the amount of nitrogen in the canopy, estimated from spectral vegetation index based on the Red-edge and the biomass. The knowledge about the NNI allows fertilizing at critical moments throughout the wheat campaign. The NNI maps for the analysed plots, were obtained throughout wheat development to flowering, of eight dates in the study campaign. The yield forecast is calculated through the relationship between biomass and the harvest index. The spatially distributed yield relies in the use of management zone maps (MZM) based on temporal series of remote sensing data. The MZMs were calculated for pre-flowering state to estimate yield, and capture the within-field variability of wheat production. Thus, the classical N balance model is used to calculate the N requirements at pixel scale, varying the target yield according to the MZM. The practical application was made in wheat commercial plots in the study area, analysing the performance of the proposed nitrogen fertilization strategies. The results indicated the possible optimization of the N application, maintaining or increasing the wheat productivity and reaching the higher levels of protein content in the area.

Keywords: Remote sensing, wheat, biomass, nitrogen nutrition index (NNI), fertilization.
Thermal imaging of sparse permeable fractures embedded in intact granite
Authors: Brixel Bernard , Klepikova Maria , Dentz Marco
Published: March 2020

Subsurface processes in rocks are often sensitive to the presence of fractures and their ability to transport fluids, solutes and heat, which depends in turn on their geometry. Characterizing parameters like fracture length and orientation is therefore an important step towards making realistic flow and transport simulations. Despite advances in computational power, state-of-the-art approaches such as discrete fracture network (DFN) models still tend to be conditioned to conventional data sources, generally hydraulic tests or solute tracer tests, providing little constrains on 3-D fracture attributes (e.g. orientation). This highlights the need for novel experimental frameworks to better resolve complex flow patterns in fractured rocks with DFN models. Here we show how borehole thermal anomalies, caused by natural flow or by heat injection experiment, can be used to detect and characterize the orientation of permeable fractures. Heat has been increasingly used as a tracer in recent years owing to the commercialization of Raman scatter-based fiber optics distributed temperature sensing (DTS) systems tailored to environmental applications. We thus present a simple framework based on analytical and/or numerical methods to extract structural information on fractures intersecting or located nearby boreholes equipped with DTS systems. Our model assumes a single fracture, embedded in an impermeable rock mass, and is validated against a series of cross-hole thermal tracer tests performed in crystalline rock at the Grimsel Rock Laboratory, in Switzerland. Active heat injection was carried out by heating water using an electrical flow-through heater up to 45°C for a duration 40 days. Fluid injection took place across a discrete, 2-m long interval packing off a single flowing fracture. A continuous fiber optics loop was deployed along three fully-grouted boreholes, which managed to record thermal breakthroughs of 1-2°C up to 6-7 meters from the injection point.  We find that orientations constrained from thermal anomalies do not necessarily correspond to structural orientations of borehole fracture traces. This orientation is defined instead by the borehole axis and maximum thermal gradient along heat-carrying fractures. Such parameter provides information on the spatial organization of discrete flow paths and may offer an alternative calibration parameter to constrain flow and transport simulations on DFNs.
Microbial life on waste: fungal communities on plastic debris from dumpsites in East Africa
Authors: Gkoutselis Gerasimos , Rambold Gerhard
Published: March 2020

The plastic waste input into terrestrial ecosystems is a serious and ongoing problem, particularly in developing countries due to deficient or non-existent recycling management. A so-called 'plastic ban' has been proclaimed in Kenya in 2017. Despite the ban, waste of all kinds of plastics, mainly polyethylene (PE) still exists at large amounts, particularly in the municipal environment of the country, where plastic solid waste (PSW) permeates the upper layers of the soil. Microorganisms are the key players in the decomposition of (polymeric) materials. Landfills (dumpsites) are designated hot spots of environmental pollution with plastics. Therefore, landfills and plastic-contaminated sites in the town of Siaya (Western Kenya) are considered suitable locations to discover with a high probability so-called soil-borne, 'plasticophilic' microorganisms. Since microfungal diversity in these regions is virtually unknown, a high-throughput method was applied to obtain a first overview on potential fungal plastic degraders and the composition of their respective communities. The focus of the screening was laid on the distinction between directly plastic-associated and generally soil-dwelling fungi. In other words, it was the aim to characterise via community barcoding associations of specifically plastic-colonizing species or OTUs in comparative analyses of both substrates, i.e. bulk soil and (macro)plastic. Ultimately, the aim of this study was to identify those 'key species' that contribute most to β̞-diversity, by far-reaching adaptations to this anthropogenic trophic niche. Eventually, this investigation marks an initiation point to a comprehensive screening in equatorial Africa for the isolation of fungi capable of plastic biodegradation.
A model for three-way carbon flux partitioning in calcareous soils using stable isotope measurements
Authors: Kirk Guy , McCloskey Chris , Otten Wilfred , Paterson Eric
Published: March 2020

In order to understand and model soil carbon (C) dynamics it is essential that we are able to partition net ecosystem C exchange by individual organic and inorganic fluxes under field conditions. Stable isotope methods provide a reliable means to separate fluxes from two sources, such as plant respiration and soil organic matter (SOM) mineralisation. In many soils, however, plant and soil respiration are not the only sources of C efflux, as breakdown of carbonate minerals provide a third, inorganic, C source. We currently lack methods and models to allow us to untangle plant, inorganic soil, and organic soil C fluxes in the field. This limits our ability to gather field-scale plant and soil C flux data to soils without inorganic carbonates, rendering calcareous soils a major gap in our understanding of, and ability to model, soil C dynamics.

To remedy this we have developed a novel three-way partitioning model to account for inorganic carbonate dissolution in a planted soil. Analysis of a mechanistic model of lime (CaCO3) dissolution showed differences in CO2 pressure in the soil, arising from differences in soil respiration as influenced by differences in temperature and moisture, to be a major control on dissolution rates. The thee-way partitioning model we have developed derives the CO2 flux from CaCO3 dissolution from SOM mineralisation and below-ground plant respiration fluxes.

To test this model we used cavity ring-down spectroscopy to measure CO2 fluxes from soil mesocosms containing C3-origin SOM and planted with a C4 grass, both with and without CaCO3, and unplanted soil mesocosms containing CaCO3. As previously field measurements revealed temperature to be the strongest control on soil respiration this was carried out at four temperatures (15, 20, 25, and 30oC). Using the distinct δ13C values for CaCO3 dissolution, C4 grass respiration, and C3 SOM mineralisation, fluxes were partitioned from mesocosms containing two C fluxes to parameterise the model. The model was tested through application to flux data from mesocosms containing C fluxes from CaCO3, SOM, and plants in order to assess its suitability for generating novel field datasets of C fluxes from calcareous soils.