bluuebunny/crossref_metadata_2025 huggingface dataset:
A Communication-Free Human-Robot-Collaboration Approach for Aircraft Riveting Process Using AI Probabilistic Planning
Authors: Rekik Khansa , Müller Rainer , Hoffmann Jörg , Vette Matthias
Published: March 2020

In large scale industries attempts are continuously being made to automate assembly processes to not only increase productivity but also alleviate non-ergonomic tasks. However this is not always technologically possible due to specific joining challenges and the high number of special-purpose parts. For the riveting process, for example, semi-automated approaches represent an alternative to optimizing aircraft assembly and to reduce the exposure of workers to non-ergonomic conditions entailed by performing repetitive tasks.

In [1], a semi-automated solution is proposed for the riveting process of assembling the section barrel of the aft section to its pressure bulkhead. The method introduced a dynamic task sharing strategy between human and robot that implements interaction possibilities to establish a communication between a human and a robot in Human-Robot-collaboration fashion. Although intuitive, interacting with the robot constantly is still not natural for the worker as in the manual process no explicit communication between both workers is needed.

In this work a communication-free Human-Robot-collaboration solution is presented. The method developed not only enables sharing assembly missions by dividing tasks based on skills, but also offers the possibility of decision making to the robot. In this context, off-the-shelf Artificial Intelligence planning tools are used to model the work-flow of the human as well as the task of the robot handling alongside possible uncertainties yielding while perceiving the environment or the activity of the human.
Advancements of Superplastic Forming and Diffusion Bonding of Titanium Alloys for Heat Critical Aerospace Applications
Authors: Burkhart Eve Taylor , Hefti Larry
Published: March 2020

Titanium’s high strength-to-weight ratio and corrosion resistance makes it ideal for many aerospace applications, especially in heat critical zones. Superplastic Forming (SPF) can be used to form titanium into near-net, complex shapes without springback. The process uses a machined die where inert gas is applied uniformly to the metal sheet, forming the part into the die cavity. Standard titanium alpha-beta alloys, such as 6Al-4V, form at temperatures between 900 and 925°C (1650-1700°F). Recent efforts have demonstrated alloys that form at lower temperatures ranging between 760 and 790°C (1400-1450°F). Lowering the forming temperature reduces the amount of alpha case that forms on the part, which must be removed. This provides an opportunity of starting with a lower gauge material. Lower forming temperatures also limit the amount of oxidation and wear on the tool and increase the life of certain press components, such as heaters and platens. A variation of this process is SPF combined with Diffusion Bonding (SPF/DB) of two or more titanium sheets to produce integrally stiffened structures with limited fasteners and less weight than comparable components. The four sheet process utilizes two core sheets with a welded cell pattern and two face sheets that are welded together along the periphery. Inert gas pressure is then applied at elevated temperature to form the sandwich structure. Recent studies have shown that dissimilar alloys with different grain sizes and flow stresses can be sufficiently diffusion bonded together. Using lower temperature alloys as the core sheet material allows the entire structure to be formed and bonded at a lower temperature regardless of the flow stress of the face sheets.
Succession of microbial community in anaerobic digestion of dairy manure induced by manure-derived biochar
Authors: Jang Hyun Min , Brady Jeff , Kan Eunsung
Published: March 2020

The present study investigates possible roles of manure-derived biochar (MBC) in anaerobic digestion (AD) of dairy manure. Addition of MBC led to an increase in cumulative methane yield and a decrease in lag phase under all tested conditions (concentration of MBC: 1 and 10 g/L, temperature: 20, 35 and 55°C). For example, the cumulative methane yield in the mesophilic AD with 10 g/L MBC were 24.51% higher than that of the AD without MBC. Additionally, lag phage of mesophilic AD with 10 g/L MBC decreased from 2.08 d to 1.52 d. Microbial community analysis indicated that the addition of MBC to mesophilic and thermophilic AD of dairy manure increased the relative abundance of Ruminofilibacter which related to the hydrolysis. In addition, the addition of MBC to AD potentially stimulated the growth of syntrophic bacteria (e.g., genera Clostridium, Syntrophomonas and Syntrophus) and hydrogenotrophic methanogens (e.g., genera Methanobacterium, Methanolinea and Methanomassiliicoccus). Furthermore, microbial community analysis also suggested that mediate interspecies electron transfer and direct interspecies electron transfer would be accelerated by addition of MBC which showed high electrical conductivity (3230 μS/cm).
The structural properties of carotid arteries in carotid artery diseases – a retrospective computed tomography angiography study
Authors: Özdemir Halil İbrahim
Published: March 2020

Purpose

Aim of the study was to find answers to the following questions: What haemodynamic changes may occur in patients with stenotic, aneurysmal, dissection of the carotid artery and its branches? How do these changes differ in patients with normal and carotid disease?

Material and methods

In order to achieve this aim, the cranio-cervical CT angiography images of patients who were referred to our clinic for any reason and received the diagnosis of carotid stenosis, carotid dissection, and extra or intracranial aneurysm were reviewed retrospectively.

Results

Significant differences were detected in the carotid arteries of normal patients and those with aneurysm and dissection. When normal and aneurismal patients were compared, right and left ICA diameters (p = 0.000, p = 0.002, respectively), total ICA diameters (p = 0.000), carotid left Ø diameters (p = 0.026), right and left total Ø diameters (p = 0.024), and Murray’s and our cosine values of Ø angles (p = 0.001 and p = 0.022, respectively) were found to be different. Also, in a comparison made between normal patients and patients with dissection, right CCA (p = 0.000), ICA (p = 0.001), ECA (p = 0.004) diameters, total CCA (p = 0.001), ICA (p = 0.009), and ECA (p = 0.003) diameters were also found to be different.

Conclusions

This study showed that the presence of aneurysm plays an important role in the remodelling of the carotid arteries. Also, it is understood that Murray’s laws are still valid for the detection of structural deterioration in carotid artery diseases. Hence, it is believed that these data can be used in artificial intelligence studies.
Multi-parametric arterial spin labelling and diffusion-weighted magnetic resonance imaging in differentiation of grade II and grade III gliomas
Authors: Khalek Abdel Razek Ahmed Abdel , El-Serougy Lamiaa Galal , Abdelsalam Mohamed A. , Gaballa Gada Mohamed , Talaat Mona Mohamed
Published: March 2020

Purpose

To assess arterial spin labelling (ASL) perfusion and diffusion MR imaging (DWI) in the differentiation of grade II from grade III gliomas.

Material and methods

A prospective cohort study was done on 36 patients (20 male and 16 female) with diffuse gliomas, who underwent ASL and DWI. Diffuse gliomas were classified into grade II and grade III. Calculation of tumoural blood flow (TBF) and apparent diffusion coefficient (ADC) of the tumoral and peritumoural regions was made. The ROC curve was drawn to differentiate grade II from grade III gliomas.

Results

There was a significant difference in TBF of tumoural and peritumoural regions of grade II and III gliomas (p = 0.02 and p =0.001, respectively). Selection of 26.1 and 14.8 ml/100 g/min as the cut-off for TBF of tumoural and peritumoural regions differentiated between both groups with area under curve (AUC) of 0.69 and 0.957, and accuracy of 77.8% and 88.9%, respectively. There was small but significant difference in the ADC of tumoural and peritumoural regions between grade II and III gliomas (p = 0.02 for both). The selection of 1.06 and 1.36 × 10-3 mm2/s as the cut-off of ADC of tumoural and peritumoural regions was made, to differentiate grade II from III with AUC of 0.701 and 0.748, and accuracy of 80.6% and 80.6%, respectively. Combined TBF and ADC of tumoural regions revealed an AUC of 0.808 and accuracy of 72.7%. Combined TBF and ADC for peritumoural regions revealed an AUC of 0.96 and accuracy of 94.4%.

Conclusion

TBF and ADC of tumoural and peritumoural regions are accurate non-invasive methods of differentiation of grade II from grade III gliomas.
Computed tomography evaluation of early post-operative complications of the Whipple procedure
Authors: Emekli Emre , Gündoğdu Elif
Published: March 2020

Purpose

Pancreaticoduodenectomy (the Whipple procedure) is the only potential curative treatment for periampullary tumours. Although mortality due to the procedure is gradually decreasing, the morbidity rates remain high. This study aimed to evaluate early computed tomography (CT) findings in patients suspected of complications following the Whipple procedure.

Material and methods

The CT images of patients who underwent the conventional Whipple procedure between January 2015 and January 2019 and underwent CT examination for the detection of early postoperative complications were retrospectively evaluated by two radiologists.

Results

The Whipple operation was performed to 65 patients, and the CT scans of 45 patients (30 males, 15 females) were included in the study. There were no complications in 21 patients. Complications were present in 24 patients (53.33%), of whom 13 had more than one complication. Eight patients had fluid collection in the operation site, two had haematoma, 10 had an abscess, and five had a pancreatic fistula. In addition, a hepatic abscess was detected in one patient, delayed gastric emptying in six patients, anastomotic leakage from the gastrojejunostomy line in two patients, superior mesenteric vein (SMV) thrombosis in two patients, and intraluminal haemorrhage and active extravasation in one patient. Mortality due to complications occurred in one patient in the early postoperative period. Other complications were treated by spontaneous, surgical or percutaneous interventional procedures.

Conclusions

Despite the decreasing mortality rates in recent years, the Whipple procedure is risky and has high morbidity even when performed in experienced centres. CT is the adequate imaging modality for the evaluation of this anatomically altered region and detection of complications.
Spring distribution of shelled pteropods across the Mediterranean Sea
Authors: Johnson Roberta , Manno Clara , Ziveri Patrizia
Published: March 2020

Abstract. Shelled pteropods represent an excellent sentinel for indicating exposure to ocean acidification (OA). Here, for the first time, we characterise spring pteropod distribution throughout the Mediterranean Sea, a region that has been identified as a climate change hot-spot. The presence of a west–east natural biogeochemical gradient makes this region a natural laboratory to investigate how the variability in environmental parameters may affect pteropod distribution. Results show that pteropod abundance is significantly higher in the eastern Mediterranean Sea where there is a higher aragonite saturation state (Ωar), showing that distribution is positively correlated with Ωar. We also observed a resilience of pteropods to higher temperatures and low nutrient conditions, including phosphorous limitation. The higher abundance of pteropods in ultra-oligotrophic conditions (eastern Mediterranean Sea) suggests that this organism can play an important role as the prime calcifying zooplankton within specific oligotrophic regions.
A Statistical Model for Automated Quality Assessment of the TOAR-II
Authors: Kaffashzadeh Najmeh , Chang Kai-Lan , Schröder Sabine , Schultz Martin G.
Published: March 2020

The Tropospheric Ozone Assessment Report, phase 2, (TOAR-II) database is a collection of global ground-level ozone in-situ measurements from various locations. It also holds data of selected ozone precursors and meteorological variables. TOAR-II assembles air quality data from many different sources and thus requires a common data quality assessment (QA) to ensure the data meet the quality required for globally consistent analyses. The large volume of this database (more than 100,000 data series) enforces the use of automated, data-driven QA procedures.

Accordingly, we have developed a statistical model for automated QA. This model consists of several statistical tests that are classified into several sub-groups. In this model, a QA-score (an indicator ranging from 0 to 1) was assigned to each individual data point to estimates the value‘s plausibility. The foundation of this concept is statistical hypothesis testing and the probability theory. This model was implemented in a Python package and is called AutoQA4Env.

One application of AutoQA4Env is the data ingestion workflow of TOAR-II. The tool generates a data quality report which is then sent back to the data provider for inspection. Since AutoQA4Env is easily configurable, it allows the users to set quality thresholds and thus filter data according to their use case. While we primarily develop AutoQA4Env for air quality data, the same concept and model might be applicable to other databases and the software framework is flexible enough to allow for other use cases.
Revealing the earthquake history during the last 200 ka on a large submarine strike-slip fault: The Yusuf Fault System (Alboran Sea)
Authors: Perea Hector , Gràcia Eulàlia , Almeida Stefanie , Gómez de la Peña Laura , Martínez-Loriente Sara , Bartolomé Rafael
Published: March 2020

The NW-SE convergence (4-5 mm/yr) between the African and Eurasian plates controls the present-day crustal deformation in the Alboran Sea (westernmost Mediterranean). Although seismic activity is mainly characterized by low to moderate magnitude events, large and destructive earthquakes (I > IX) have occurred in this region (i.e., 1522 Almeria, 1790 Oran, 1910 Adra, 1994 and 2004 Al-Hoceima or 2016 Al-Idrissi earthquakes). The identification and the seismogenic characterization of the active structures in the Alboran Sea using ultra high-resolution (UHR) geophysical data is essential to evaluate better the exposure of the South Iberian Peninsula and North African coasts to related natural hazards (i.e., large earthquakes and related tsunamis and triggered landslides). During the SHAKE cruise, the Asterx and Idefx AUVs (Ifremer, france) were used to acquire UHR bathymetric (1m grid) and seismic (cm vertical resolution) data across the main active faults systems in the Alboran Sea with the aim to carry out sub-aqueous paleoseismological studies. One of the studied active structures has been the Yusuf Fault System (YFS), a dextral strike-slip system that is one of the largest structures in the Alboran Sea and a lithospheric boundary between different crustal domains: the East Alboran Basin to the north and the North African Margin to the south. It trends WNW-ESE, is ~150 km-long and can be divided into two main segments (W and E), producing the formation of a pull-apart basin where both overlap. The analysis of the UHR geophysical dataset reveals that in the imaged area this system is a complex structure composed by an array of strike-slip faults. Most of them reach up and offset the seafloor and the upper Pleistocene to Holocene sedimentary units. The results of the on-fault paleoseismological analyses reveal that the YFS may have generated at least 8 earthquakes in recent times. Although a detailed on-site geochronology is not available, a regional chronostratigraphic correlation have allowed estimating that the events have occurred during the last 200 ka, then providing an average recurrence interval of 27.5 ka. The estimated average vertical offset is about 0.64 m while the vertical slip-rate would be around 0.03 mm/yr. However, this value needs to be considered as a minimum since YFS is predominantly a strike-slip fault and the lateral slip will be much larger than the vertical one. According to different empirical relationships, the YFS could produce earthquakes above magnitude Mw 7.0. Finally, our results demonstrate that detailed geomorphological, active tectonic and paleoseismological studies are essential to reveal the present-day activity and to characterize the seismic behavior of the YFS, with crucial implications for seismic (and tsunami) hazard assessment in the surrounding coastal areas.
Near real time plasma irregularity monitoring by FORMOSAT-7/COSMIC-2
Authors: Chen ShihPing , Lin Charles C. , Panthalingal Krishnanunni Rajesh , Eastes Richard , Choi Jong-Min
Published: March 2020

The near real-time global plasma bubble map is constructed by utilizing the FORMOSAT-7/COSMIC-2(F7/C2) radio occultation(RO) scintillation observations in low latitudes. Several tools investigating plasma bubbles like the rate of TEC index(ROTI), Range-Time-Intensity(RTI) diagrams of the Jicamarca Unattended Long-term Investigations of the Ionosphere and Atmosphere(JULIA), and the Global-scale Observations of the Limb and Disk(GOLD) 135.6nm airglow observations are provided validating the RO scintillations. Result shows that the F7/C2 scintillation is sensitive detecting plasma irregularities, especially for the bottom side of these bubbles, which can be used to investigating nighttime vertical plasma drifts in low latitudinal F-region. The hourly quick look of the low latitude plasma bubble occurrence and vertical ion drift around the globe is significant to the space weather monitoring.
Global climate changes during the most recent two millennia
Authors: Eggleston Sarah S. , Bothe Oliver , Abram Nerilie , Konecky Bronwen , Linderholm Hans , Martrat Belen , McGregor Helen , Phipps Steven , St. George Scott
Published: March 2020

The past two thousand years is a key interval for climate science because this period encompasses both the era of human-induced global warming and a much longer interval when changes in Earth's climate were governed principally by natural drivers. This earlier 'pre-industrial' period is particularly important for two reasons. Firstly, we now have a growing number of well-dated, climate sensitive proxy data with high temporal resolution that spans the full period. Secondly, the pre-industrial climate provides context for present-day climate change, sets real-world targets against which to evaluate the performance of climate models, and allows us to address other questions of Earth sciences that cannot be answered using only a century and a half of observational data. 

Here, we first provide several perspectives on the concept of a 'pre-industrial climate'. Then, we highlight the activities of the PAGES 2k Network, an international collaborative effort focused on global climate change during the past two thousand years. We highlight those aspects of pre-industrial conditions (including both past climate changes and past climate drivers) that are not yet well constrained, and suggest potential areas for research during this period that would be relevant to the evolution of Earth's future climate.
Evolution of low flows regulation and terrestrial water storage in the Magdalena river basin: Implications for the assessment and monitoring of potential water scarcity in river basins
Authors: Salazar Juan F. , Bolaños Silvana , Rodríguez Estiven , Betancur Teresita , Villegas Juan Camilo , Werner Micha
Published: March 2020

Many natural and social phenomena depend on the regulation of river flow regimes. Regulation is defined here as the capacity of river basins to attenuate extreme flows, which includes the capacity to enhance low flows during dry periods of time. This capacity depends on how basins store and release water through time, which in turn depends on manifold processes that can be highly dynamic and sensitive to global change. Here we focus on the Magdalena river basin in northwestern South America, which is critical for water and energy security in Colombia, and has experienced water scarcity problems in the past, including the collapse of the national hydropower system due to El Niño 1991-1992. In this basin we study the evolution of regulation and related processes from two perspectives. First, we present a widely applicable conceptual framework that is based on the scaling theory and allows assessing the evolution of regulation in river basins, and use this framework to show how the Magdalena basin’s regulation capacity has been changing in recent decades. Second, we use data from the GRACE mission to investigate variations in water storage in the basin, and identify recent decreasing trends in both terrestrial water storage and groundwater storage. Further we show that temporal and spatial patterns of water storage depletion are likely related to the occurrence of ENSO extremes and pronounced differences between the lower and higher parts of the basin, including the presence of major wetland systems in the low lands and Andean mountains in the high lands. Our results provide insights on how to assess and monitor regulation in river basins, as well as on how this regulation relates to the dynamics of low flows and water storage, and therefore to potential water scarcity problems.
Seismic localization and dynamical characterization of snow avalanches and slush flows of Mt. Fuji, Japan
Authors: Pérez-Guillén Cristina , Tsunematsu Kae , Nishimura Kouichi , Issler Dieter
Published: March 2020

Snow avalanches and slush flows are often released at the stratovolcano of Mt. Fuji, which is the highest mountain of Japan (3776 m a.s.l.). These flows represent a major natural hazard as they may attain run-out distances up to 4 km, destroy parts of the forest, and sometimes damage infrastructure. We detected large dimension flows released in the winter seasons of 2014, 2016 and 2018 using the local seismic network installed to monitor the volcanic activity of Mt. Fuji. The maximum detection distance of the seismic network is approximately 15 km for the largest avalanche size class 4–5 (Canadian avalanche classification).  Using data from several seismic sensors, we applied the automated approach of amplitude source location (ASL) based on the decay of the seismic amplitudes with distance to localize and track the avalanche flow paths. We also conducted numerical simulations with Titan2D to reconstruct the avalanche trajectories and thus to assess the precision of the seismic tracking as a function of time, showing mean location errors ranging between 85 and 271 m. The average front speeds estimated from the seismic tracking, which ranged from 27 to 51 m s−1, are consistent with the numerically predicted speeds. In addition, we correlated the source amplitudes and the estimated seismic energies with the approximate run-out distances of the avalanches deduced from the ASL method. The obtained scaling relationships can be useful to empirically classify the flow size. An important task in the near future will be to develop highly effective methods for automatically detecting and tracking avalanche events in the seismic data in near-real time. One approach for the automatization of avalanche detection is the discrimination of seismic sources in the continuous recordings by applying machine learning classification methods. We expect that the precision of the flow tracking could be improved through adaptive weighting of the signals from different stations according to the source–receiver distances and angles.

 

 
Multiple hazards under future UK Climate Projections
Authors: Garry Freya , Bernie Dan
Published: March 2020

When two or more extreme weather events occur either simultaneously or in close succession, there may be more severe societal and economic impacts than when extreme hazards occur alone. Impacts may also cascade across different sectors of society or amplify impacts in another sector. Perturbed parameter ensemble simulations of projections to 2080 have been generated at the UK Met Office to cover the UK at high spatial (12 km or 2.2 km) and temporal resolution (daily or sub-daily) resolution as part of the “UK Climate Projections”. We use the regional 12 km model simulations at daily resolution to consider how the frequency, duration and spatial extent of multiple extreme hazard events in the UK changes over the 21st century. We will show case studies of multiple extreme hazard pairings that pose a risk to UK sectors, for example, the risk of hot and dry weather to agricultural harvests. By working with stakeholders that have a good understanding of their vulnerabilities and exposure, we consider multiple extreme events in a risk projection framework. This work is funded under the Strategic Priority Fund for UK Climate Resilience.
Projection of land and ecosystem degradation for preventing risk of natural capital decline in Tibet plateau.
Authors: Zhang Lu
Published: March 2020

Numerous methodologies are available so far measuring trends of land (LD) and ecosystem degradation (ED) with spatially explicit manner. Yet the delineation of spatial and temporal covariance between LD and ED remains challenging which limited the effectiveness of future conservation decision making for preventing risks of LD and ED simultaneously, especially in cold and drought areas because of high cost of restoration. Here, we produced the spatial networks for managing and restoring LD and ED based on the risk projection of LD and ED in Tibet plateau under human exploitation pressure and climate change. Firstly, we simulated 10 indicators for LD and ED separately by monthly interval from 2000 to 2015 to capture the current trends of LD and ED. Secondly, resilience, resistant, and risk exposure have been assessed to connect the vegetation traits, threaten factors and their reflections. Thirdly, by the exploration of relationship between LD and ED and their impact factors, we projected risks for both of them using 12 scenarios from different climate and land use change combinations identifying the key area of preventing LD and ED spatially. Finally, an effectiveness analysis has been processed ordering results under each scenarios leaded to the decline of nature capital for providing alternative strategies of regional land and ecosystem management. By our research, we found that LD and ED in Tibetan plateau have similar pattern of dynamic, while ED shows more significant correlation with climate change due to stronger intrinsic resilience in front of stressors. In opposites, once serious land degradation occurs, it is hardly being recovered by increasing of precipitation and temperature. Based on the relationship analysis, we modeled LE and ED risks under various potential scenarios suggesting that at least 100,000km2 area needed to human intervention for restoration. These suggested sites covered the worst 60% areas of both LD and ED producing 12.5 billion USD  dollars revenue from the maintenance of key regulating ecosystem services.
Advanced harmonization and sensor fusion to transform data readiness and resolution for big data analytics
Authors: Houborg Rasmus , Marchisio Giovanni
Published: March 2020

Access to data is no longer a problem. The recent emergence of new observational paradigms combined with advances in conventional spaceborne sensing has resulted in a proliferation of satellite sensor data. This geospatial information revolution constitutes a game changer in the ability to derive time-critical and location-specific insights into dynamic land surface processes. 

However, it’s not easy to integrate all of the data that is available. Sensor interoperability issues and cross-calibration challenges present obstacles in realizing the full potential of these rich geospatial datasets.

The production of analysis ready, sensor-agnostic, and very high spatiotemporal resolution information feeds has an obvious role in advancing geospatial data analytics and machine learning applications at broad scales with potentially far reaching societal and economic benefits. 

At Planet, our mission is to make the world visible, accessible, and actionable. We are pioneering a methodology--the CubeSat-Enabled Spatio-Temporal Enhancement Method (CESTEM)--to enhance, harmonize, inter-calibrate, and fuse cross-sensor data streams leveraging rigorously calibrated ‘gold standard’ satellites (i.e., Sentinel, Landsat, MODIS) in synergy with superior resolution CubeSats from Planet. The result is next generation analysis ready data, delivering clean (i.e. free from clouds and shadows), gap-filled (i.e., daily, 3 m), temporally consistent, radiometrically robust, and sensor agnostic surface reflectance feeds featuring and synergizing inputs from both public and private sensor sources. The enhanced data readiness, interoperability, and resolution offer unique opportunities for advancing big data analytics and positioning remote sensing as a trustworthy source for delivering usable and actionable insights.
FVM approach for solving the oblique derivative BVP on unstructured meshes above the real Earth’s topography
Authors: Medľa Matej , Mikula Karol , Čunderlík Róbert
Published: March 2020

We present local gravity field modelling based on a numerical solution of the oblique derivative bondary value problem (BVP). We have developed a finite volume method (FVM) for the Laplace equation with the Dirichlet and oblique derivative boundary condition, which is considered on a 3D unstructured mesh about the real Earth’s topography. The oblique derivative boundary condition prescribed on the Earth’s surface as a bottom boundary is split into its normal and tangential components. The normal component directly appears in the flux balance on control volumes touching the domain boundary, and tangential components are managed as an advection term on the boundary. The advection term is stabilised using a vanishing boundary diffusion term. The convergence rate, analysis and theoretical rates of the method are presented in [1].

Using proposed method we present local gravity field modelling in the area of Slovakia using terrestrial gravimetric measurements. On the upper boundary, the FVM solution is fixed to the disturbing potential generated from the GO_CONS_GCF_2_DIR_R5 model while exploiting information from the GRACE and GOCE satellite missions. Precision of the obtained local quasigeoid model is tested by the GNSS/levelling test.

 

[1] Droniou J, Medľa M, Mikula K, Design and analysis of finite volume methods for elliptic equations with oblique derivatives; application to Earth gravity field modelling. Journal of Computational Physics, s. 2019
Using Variance Maximization with Multi-species Measurements to Pinpoint the Sources and Long Range Transport of Biomass Burning over the Past 15 Years
Authors: Deng Weizhi , Cohen Jason
Published: March 2020

Trace gases and aerosols in the troposphere exhibit significant variability, particularly so over regions where biomass burning occurs, and downwind of both biomass burning and large urban areas. Knowledge and quantification of the mean, trends, and most importantly variance over these source regions and their downwind plumes over climatological scales can therefore be used to retrieve information about both the source amounts as well as the amounts transported.

In this work, we pinpoint a way to separate these regions from one another by simultaneously employing a variance maximization approach to global weekly column measurements of OMI NO2 (which has a very short atmospheric lifetime) and MOPITT CO (which has a relatively long atmospheric lifetime) from the past decade and a half. The variance maximization is done using the EOF/PCA approach, and yields important results in northern Australia, Indonesia, northern Southeast Asia, Siberia, central and southern Africa, Amazonia and California. We then compare and contrast the spatial and temporal results in terms of the difference in the atmospheric lifetime of the co-emitted species. We specifically look for an overlap between the two over the source regions, and a strong signal in CO exclusively over both the source and downwind transport regions.

This technique improves upon the current generation of bottom-up techniques detecting land-use change and hotspots, in terms of offering higher temporal resolution and better representations under cloud cover. However, to further improve the work, we hope to employ AOD measurements to refine our results, as co-emitted aerosols like BC are sensitive to precipitation, and thus able to pick up the source and transport under different precipitation conditions.
I3S - an open standard for 3D GIS visualization on Web, Desktop and Mobile Platforms
Authors: Belayneh Tamrat
Published: March 2020

This session will focus on Indexed 3D Scene Layers (I3S) and its evolution, as an OGC (Open Geospatial Consortium) community Standard. I3S enables the storage and streaming of massive amounts of heterogeneously distributed geospatial content, in the form of millions of discrete 3D objects with attributes, integrated surface meshes and point cloud data covering vast geographic areas, to web browsers, mobile apps and desktop.

Ability to stream millions of triangles and billions of point cloud, regardless of platform constraints, has opened a new 3D graphics and visual computing front in the geospatial world, where there is an increasing demand for high quality 3D application.

In this session, we will describe principles and concepts for organizing geospatial data based on bounding volume hierarchy (BVH), various spatial subdivision algorithms, efficient mesh representation, as well as exploring point cloud, mesh and texture compression/decompression techniques, while keeping the content friendly to GPUs. We will also demonstrate various examples of the different layer types and profiles that are supported in I3S and how the data structure and organization help to efficiently store segmentation/classification information as well as triangle/point level attribution.

Technological advancements in 3D graphics, data structuring, mesh and texture compression, efficient client-side filtering and so forth have significantly contributed to a paradigm shift in how geospatial content is created and disseminated, regardless of size and scale. Formats such as I3S now allow 3d content to be authored/created once and be efficiently consumed in various platforms including desktop, web and mobile for both offline and online access. This phenomenon – create once and consume everywhere model, has encouraged the dissemination and sharing of geospatial content for both planetary (whole earth) and planar 3D visualization experiences.

The session will show case numerous examples (for desktop, web and mobile experience) illustrating the many advancements made in geospatial technologies that are ripe to be embraced in various geoscience disciplines.

The I3S specification was released as a free and open standard by Esri and has been adopted as an OGC community standard for the past 2 and half years and is evolving vastly with many use cases.
Analysis of groundwater storage changes in main Polish river basins using GRACE observations, in-situ data, and hydrological and climate models
Authors: Nastula Jolanta , Śliwińska Justyna , Rzepecka Zofia , Birylo Monika
Published: March 2020

The Gravity Recovery and Climate Experiment (GRACE) measurements have provided global observations of total water storage (TWS) changes at monthly intervals for almost 20 years. They are useful for estimating changes in groundwater storage (GWS) after extracting other water storage components like soil water or snow water.

In this study, we analyse the GWS variations of two main Polish basins, the Vistula and the Odra, using GRACE observations, in-situ wells measurements, GLDAS (Global Land Data Assimilation System) hydrological models, and CMIP5 (the World Climate Research Programme’s Coupled Model Intercomparison Project Phase 5) climate data. The research is conducted for the period between September 2006 and October 2015.

Here, TWS is taken directly from GRACE measurements and also computed from all considered models. GWS is obtained by subtracting the modelled sum of soil moisture and snow water from the GRACE-based TWS. The resultant GWS series are validated by comparing with appropriately calibrated in-situ wells measurements. For each GWS time series, the trends, spectra, amplitudes, and seasonal components were computed and analysed. The results suggest that in Poland there has been generally no major GWS depletion. The results can contribute toward selection of an appropriate model that, in combination with GRACE observations, would provide information on groundwater changes in regions with limited or inaccurate in-situ groundwater storage measurements.
3D basin-scale groundwater flow modeling as a tool for geothermal prospection of the Geneva Basin, Switzerland-France
Authors: Alcanie Marion , Collignon Marine , Møyner Olav , Lupi Matteo
Published: March 2020

Switzerland supports the energetic transition by promoting the development of geothermal energy among other renewable energies. In particular, the Canton of Geneva is actively prospecting the Geneva Basin, generating a large dataset of geophysical and geological information. This large dataset of the Geneva Basin is used here to constrain geologically complex numerical models of fluid flow. Previous and ongoing projects demonstrated the geothermal potential of the Geneva Basin but a consistent basin-scale fluid flow model of the area has yet to be defined.

We use MRST (Matlab Reservoir Simulation Toolbox) for which we recently developed a geothermal module. The module is available with the last MRST release (2019b) and it is used to build up a 3D basin-scale dynamic model of the Geneva Basin. The goal of our numerical study is to investigate the large-scale control of tectonic structures and lithological hetherogeneities on fluid flow in the basin.

The static model is derived from active seismic and gravity inversion data. Petrophysical data and geo-location of faults are obtained from the existing literature. The resulting heterogeneous model takes into account the main geological facies, observed in the basin. We define a reference simulation with standard initial conditions (geothermal gradient and hydrostatic pressure topographically corrected) and a basal incoming heat flux. We consider a single-phase pure water compressible laminar flow in porous media. The geothermal module solves the mass and energy conservation equations using a fully implicit finite-volume discretisation with two-point flux approximation and single-point upstream mobility weighting.

We design a parametric study along three main axis: tectonic structures (i.e. faults), petrophysical and thermal properties and perform twenty three simulations running for 500 000 years to reach an equilibrium flow (steady-state). Our results show that fluid flow is driven by the hydraulic head of the topographic highs bounding the basin. Hotter fluids are found in the centre of the basin where we propose to focus geothermal exploitation in the future. Our results represent, to our knowledge, the first example of 3D basin-scale fluid flow modelling used as a preliminary prospection method for the assessment of geothermal resources.
Assessing impacts of future potential climate change scenarios on snow cover area by using cellular automata models and Montecarlo simulations
Authors: Pulido-Velazquez David , Collados-Lara Antonio-Juan , Pardo-Igúzquiza Eulogio
Published: March 2020

Climate change will modify the availability of snow resources in the future. Thus developing methodologies to assess impacts of potential future climate change scenarios on snow variables is a key subject. In this work we combine several previous developed methodologies (downscaling climate change scenarios to local scale, cellular automata models, and stochastic weather generators) to assess impacts of future climate change scenarios and its uncertainty on snow cover area through a Montecarlo simulation. The cellular automata model uses climatic indices (precipitation and temperature) as driving variables to estimate snow cover area. Future scenarios of these variables can be generated using bias correction and delta change approaches and different regional climate models. The stochastic weather generators allow us to produce multiple series of precipitation and temperature based on the statistical characteristics of the future local scenarios generated. These multiple series can be used as inputs of the cellular automata model in order to assess the future snow cover area and its uncertainty. The main advantages of the proposed methodology are its applicability in cases with limited information and in mountain ranges scales. The methodology has been applied to the Sierra Nevada mountain range in southern Spain. This area has a Mediterranean climate very sensitive to climate change. Using the future precipitation and temperature scenarios generated considering the Representative Concentration Pathways 8.5 (RCP8.5) for the period 2071–2100, we obtain a significant reduction in snow cover area, with mean values of 59.0% for the local scenarios generated with a delta change approach, and 61.7% for those one generated with the bias correction approach.

This research has been partially supported by the SIGLO-AN project (RTI2018-101397-B-I00) from the Spanish Ministry of Science, Innovation and Universities (Programa Estatal de I+D+I orientada a los Retos de la Sociedad).
Introduction to the current status of solar magnetic field measurements in China
Authors: Deng Yuanyong
Published: March 2020

Solar magnetic field is a key paramters to understand the solar activity and its influence to the interplanetary space in the solar system. The solar magnetic field measurement is always an enormous challenge to the solar community. We firstly overview the history of solar magnetic field measurement since last early century and analyze the difficulty and progress of pratical methods. Then we introduce an infrared system for the accurate measurement of solar magnetic field (AIMS) and its current progress, which is supported by National Natural Science Foundation of China and also the current ongoing space based projects (ASO-S/FMG) to measure the solar magnetic field in China.
Stratospheric influence on idealised baroclinic life cycles
Authors: Rupp Philip , Birner Thomas
Published: March 2020

The importance of understanding the dynamical coupling of troposphere and stratosphere to make accurate weather and climate predictions is well-known. Over the past years and decades various signatures of such a
coupling have been discovered. A very robust result, for example, seems to be an equatorward shift of the tropospheric eddy driven jet following sudden stratospheric warming events, where the westerly winds of the stratospheric polar vortex weaken or even reverse. However, many aspects of this fundamental coupling are still not fully understood and research on how the state of the stratosphere can influence the tropospheric circulation and what dynamical processes are involved is still ongoing.

An important such process arises due to the interaction of a sharp, localised maximum in potential vorticity gradient near the tropopause with baroclinic eddies in the troposphere. Here, we analyse the sensitivity of baroclinic wave development and evolution to changes of various basic state characteristics, by performing a series of idealised baroclinic eddy life cycle experiments. Special attention is paid to sensitivities associated with the dynamical state of the stratosphere. We find that the final (steady) state of the life cycle simulations corresponds to an equatorward shift of the tropospheric jet in cases where the initial conditions do not include a stratospheric polar vortex (such as following sudden warming events) compared to those that do. These results further support the idea that the stratospheric state can strongly influence tropospheric dynamics and, in particular, highlight the robustness of the jet shift response following sudden warmings, that can be seen in a range of observations and numerical model experiments.
Microplastics in agroecosystem – effects of plastic mulch film residues on soil-plant system
Authors: Qi Yueling , Yang Xiaomei , Huerta Lwanga Esperanza , Garbeva Paolina , Geissen Violette
Published: March 2020

In the last decades, the use of plastic mulch film in (semi-) arid agricultural regions has strongly increased. Plastic residues from mulching remain and accumulate in soil that can lead to serious environment problems. Biodegradable plastic mulch films were produced as environmentally friendly alternative for solving plastic pollution in agricultural land. However, the effects of polyethylene and biodegradable mulch film residues on soil-plant system are largely unknown.

In this PhD project, we performed a series of experiments to assess the effects of low density polyethylene (LDPE) and biodegradable plastic (Bio, made of polyethylene terephthalate, polybutylene terephthalate, pullulan) with macro- (5 mm2, Ma) and micro- (50 µm-1 mm, Mi) sizes on wheat growth, rhizosphere microbiome, soil physicochemical and hydrological properties and soil suppressiveness. The results showed that plastic residues presented negative effects on both above- and below-ground  parts for both vegetative and reproductive development of wheat. We also identified significant effects of Bio and LDPE plastic residues on the rhizosphere bacterial communities and on the blend of volatiles emitted in the rhizosphere. Tested with a gradient in concentration of plastic residues (0, 0.5%, 1% and 2% w/w), soil physicochemical and hydrological properties nonmonotonically responded to residual amount of plastic debris in the soil. Lastly, although we did not observe effects of plastic residues on disease infection in our experiment, we anticipated that soil suppressiveness and other soil functions would be affected with the presence of plastics in soil.

Overall, our study provides evidence for impacts of plastic residues on the soil-plant system, suggesting urgent need for more research examining their environmental impacts on agroecosystems.
The dependence of deep-nightside Martian ionosphere TEC on crustal magnetic field
Authors: Qin Junfeng , Zou Hong , Ye Yuguang , Wang Jinsong , Nielsen Erling
Published: March 2020

It has been clear that the main cause of Martian deep-nightside ionosphere is electron precipitation, which is dominated by Martian crustal magnetic field. In this research, the dependence of deep-nightside Martian ionosphere TEC (Total Electron Content) on crustal magnetic field was studied based on Martian ionospheric TEC data from MEX/MARSIS and 400km crustal magnetic field data from MGS. It is found that the strength and inclination of crustal magnetic field have great effects on Martian deep-nightside ionospheric TEC. This kind of effects are worth to be compared with the effects of crustal magnetic field on electron precipitation studied in previous researches (such as Lillis and Brain, 2013, Nightside electron precipitation at Mars: Geographic variability and dependence on solar wind conditions) to find out more about the formation of Martian deep-nightside ionosphere. It is also found that, in a Martian crustal magnetic field cusp region, the observed deep-nightside ionospheric TECs in the center of the cusp are lower than those in the edge of the cusp, a phenomenon not noticed before. It indicates that there may be more precipitated electrons moving along the closed crustal magnetic lines than moving along open crustal magnetic lines, and these precipitated electrons in closed magnetic lines can be related to the energy processes in the nightside of Mars, such as magnetic reconnections.