bluuebunny/crossref_metadata_2025 huggingface dataset:
Detecting subsurface interfaces with a physics-based level-set segmentation and additional geological constraints
Authors: Wellmann Florian , Berkels Benjamin
Published: March 2020

Sharp interfaces often separate regions in the subsurface with distinctively different properties due to processes in geological evolution – and these   interfaces are relevant for a variety of scientific investigations, as well as practical applications.  The delineation of these layers with different properties is commonly attempted on the basis of geological and geophysical data, for example as picks in  prevalent seismic reflectors, interpreted from potential field measurements, and derived from observations in drillholes. 

We evaluate here a specific method to determine the position and shape of such an interface using measurements of state variables related to a physical flow field described with an elliptic PDE. A typical example is the measurement of temperatures related to heat flow through zones with distinctively different thermal conductivities. We use a level-set function to describe the interface and determine the optimal interface shape for a 2-D case. This type of shape inversion has been successfully attempted before, and we extend on this previous work by including additional shape constraints on orientation, interface, and observations of specific segmentation outcomes. These constrains are motivated by geological information that may be available, for example as derived and interpreted from additional geophysical measurements. 

We model this as an image segmentation problem, where we are looking for a segmentation of the image domain whose induced temperature minimizes the squared L2 distance to temperature measurements on a lower dimensional set. From an optimal control perspective, the segmentation is the control and the temperature the state.  Numerically, the segmentation is represented by a level set and the minimization is done using a gradient flow, where the derivative with respect to the level set is computed using dualization. Moreover, we include additional geologically motivated constraints by adding soft penalties to the objective function.

We test our method with several conceptual examples to determine the feasibility and limitations, especially with regard to different interface shapes and the amount of available information and additional geological constraints, as well as the influence of noise on the detection  accuracy. Results show that these additional constraints help determining an interface. However, measurement noise and a non-homogeneous spatial distribution of physical properties reduces the accuracy of the derived interface. 
Making use of open geo-environmental and agricultural datasets to model NO3 pollution in groundwater bodies
Authors: Schneider Christian
Published: March 2020

In Germany a vast amount of spatial geo-environmental as well as climatic datasets is available. But anthropic data on land-use and agriculture are still very sparse making it difficult to assess the environmental impacts of different agricultural practices. Recently, some data on spatial pattern of crop production as well as livestock production was made publicly available. It opened up the opportunity to model the impact of agriculture on nitrate leaching into groundwater bodies.

A high share of groundwater bodies in Germany contains nitrate levels above the legal threshold of 50 mg l-1. Our study aims to answer the question: to what extend different types of agriculture are contributing to NO3 leaching into ground water bodies in relation to environmental factors.

We use the random forest (RF) machine learning algorithm to model and predict nitrate exceedance in ground water bodies. The advantage of the RF algorithm is that it has a high predictive accuracy, it is able to use metric as well as multi-level categorical datasets and it calculates a variable importance measure for each predictor used in a model. It therefore gives a measure to which extend each predictor contributes to the accuracy of the model. For this study we applied the RF classification as well as the RF regression algorithms on different spatial scales.

Out of 56 environmental predictor datasets which are of potential importance for NO3 transport into groundwater bodies 22 where chosen to model NO3-exceedance.
A recursive variable elimination scheme was applied to calculate minimum predictor sets based on variable importance. In the end the predictor set which resulted in the most accurate NO3 prediction was identified and used to model groundwater pollution.

RF-modeling proofed to be successful on all three scale levels with OBB accuracy between 0.82 and 0.95. At all scale levels environmental co-variables played a major role in predicting NO3-exceedance. But the RF variable importance measure could also be used to identify the contribution of agricultural predictors to NO3 exceedance and to quantitatively proof our hypotheses.

On main challenge was to identify the influence of data quality on the RF variable importance measure.
Conditions for topside ionline enhancements
Authors: Rexer Theresa , Gustavsson Björn , Leyser Thomas , Rietveld Mike
Published: March 2020

High frequency (HF) enhanced ion line spectra as a response to magnetic field aligned HF pumping of the polar ionosphere in an O-mode polarization can be observed at the top and bottomside F-region ionosphere under certain conditions. The European Incoherent Scatter (EISCAT) UHF radar was directed in magnetic zenith on 18th and 19th October 2017 while stepping the pump frequency of the EISCAT Heating facility across the double resonance frequency of the fourth harmonic of the electron gyrofrequency and the local upper hybrid frequency, in a 2-min-on, 2-min-off pump cycle, stepping both upward and downward in frequency. We present observations of two separate cases of topside HF enhanced ion lines (THFIL). THFIL simultaneous to bottomside HFIL (BHFIL) and conditioned by the relative proximity to the double resonance frequency, consistent with previous observations \citep{Rexer2018} were observed for heating pulses on 19th October. Recurring THFIL with a second set of characteristics were observed on 18th October, appearing independently from BHFIL and possibly conditioned by the proximity of the topside double resonance frequency. Propagation of the pump wave to the topside ionosphere is consistent with L-mode wave propagation facilitated by density striations in the plasma. We consider the conditions for the occurrence of THFIL for two cases/types of observations. 
A case study aiming to promote cities resilience based on urban critical zone management as a whole
Authors: Diaz Marion , Thomas Zahra , Prenveille Alain , Floch Nicolas
Published: March 2020

Adaptation to global changes and promotion of cities resilience requires the development of integrated approaches to take into account the urban critical area as a whole. The major challenge is to assess this integrated approach evolving the main actors taking part on critical zone management. One way to do so might be the development of a network of actors and scientists committed to the long-term evolution of practices and having a common strategy for territories use. The poster presents a case study aiming to implement an integrated water management strategy in urban development based on the organization of a network of territory actors and scientists. The methodology here presented was built to focus on three main questions: what specific problems does integrated water management reveal for the various stakeholders? What are their usual opportunities of exchange and information? And which organization allows them to solve their problems, while taking into account the pre-existing networks on water management?. To answer these questions, we conducted comprehensive interviews with water and development stakeholders and representatives of networking organization.

Our results highlights the need of collaborative development of urban projects between planners and water managers: each of them is confronted with a diversity of concerns related to several factors, such as

their position as a stakeholder in the intentional management of water or in the effective management of water;

the scope of responsibilities of local communities in the management of wastewater, stormwater, drinking water, biodiversity ;

the specific regional characteristics (coastal territories, morphologies of urban area).

Moreover, the results show that the existing networks address partially some of the questions: the study highlights in particular the lack of dialogue and knowledge transfer between water management actors and urban development actors, resulting in the design of urban projects that are not adapted to the new standards of urban management (e.g. stormwater). In addition, research projects are emerging in relation to big cities issues, but are sometimes in competition with each other. Also, the dissemination of results remains reserved for cities already endowed with significant engineering capacities.

Improvements in the networking is required to promote integrated urban water management, we come up with three organizational scenarios including objective analysis of existing networks of the main actors. The implementation of an integrated approach to hydrological systems linked to energy efficiency in urban areas requires taking into account the critical zone as a whole.
Evaluation of the subject geological area suitability for oil recovery by High-Pressure Air Injection method
Authors: Aysylu Askarova , Alexander Cheremisin , Aleksei Solovyev , Alexey Cheremisin
Published: March 2020

The considerable decline of conventional oil and gas reserves and respectively their production introduces new challenges to the energy industry. It resulted in the involvement of hard-to-recover reserves using advanced enhanced oil recovery (EOR) techniques. Thermal methods of EOR are recognized as most technically and commercially developed methods for the highly viscous crude. High-Pressure Air Injection (HPAI) is one of the thermal production methods that reduce oil viscosity and increases the recovery (Yoshioka et al, Moore et al., 2002). HPAI has been already effectively applied for different types of reservoirs development and proven to be economically feasible. 

The application performance of the HPAI technology strongly depends on the quality of experimental and numerical modeling conducted on the the target object basis. Prior to the field tests physicochemical and thermodynamic characteristics of the process were studied. Further consequent numerical modeling of laboratory-scale oxidation experiments and field-scale simulation were conducted to estimate HPAI method feasibility based on the results of oxidation studies. A medium pressure combustion tube (MPCT) oxidation experiment was carried out to provide stoichiometry of the reactions and field design parameters. A 3D numerical model of the MPCT experiment was constructed taking into account the multilayer design, thermal properties, heating regimes and reaction model (Sequera et al., 2010; Chen et al., 2014; Yang et al., 2016). The “history” matched parameters such as fluid production masses and volumes, temperature profiles along the tubes at different times and produced gas composition demonstrated good correspondence with experimental results. The results obtained during the experiment and modeling of MPCT (fluid properties, relative phase permeability, kinetic model, technological parameters) were used in field-scale modeling using various thermal EOR scenarios. Air breakthrough into production wells was observed, thus a 2 percent oxygen concentration limit where implied. The overall performance of four different scenarios was compared within 15 years timeframe. The development system was also examined to achieve the maximum economic indicators with the identifications of risks and main uncertainties.

 
Gridded Emission Inventory of Criteria Air Pollutants for National Capital Territory, Delhi
Authors: Chaurasia Rahul , Mohan Manju
Published: March 2020

The megacities of the world are experiencing a punishing level of air pollution where primary sources of emissions are industrial, residential and transportation. Delhi is also no exception and had been worst performing in terms of air quality and air pollution. In this backdrop, a high-resolution emission inventory becomes an essential tool to predict and forecast pollutant concentration along with the assessment of the impact of various government policies. This study aims to prepare a high-resolution gridded emission inventory (1km*1km) of criteria air pollutants (PM10, PM2.5, NO2, SO2 and CO) for Delhi-NCT (National Capital Territory).  The bottom-up gridded emission inventory has been prepared taking account of population density, land use pattern and socio-economic status. The emission from all the primary sectors has been taken into accounts such as transport, residential burning, industries, power plants, and municipal solid waste burning.  The emissions are estimated using emission factors and activity data for each sector. The emission factor for various fuel type burning is taken from CPCB (Central Pollution Control Board) reports and previous literature. Data corresponding to various sectors such as the amount of fuel consumed, population density, road density, traffic congestion points, industrial location, unauthorized colonies, slums, and total solid waste generation has been acquired from various government bodies, reports, and literature. The result reveals that the total estimated emissions from transportation, industries and domestic sector contribute nearly 72%, 60%, 52% of NOx, SO2 and PM10 emission respectively.  The transport sector has been found as the bulk contributor towards CO and NOx emissions. Domestic sector and Power plant emission have been found to be a bulk contributor of CO and SO2. Later, the spatial distribution of the emission is done using GIS technique (Arc-GIS). For spatial distribution of emission, district-wise population data, road density data, power plant location and digitization of the road network was carried out.
Metereological factors modulating coffee rust in the central area of Veracruz, Mexico
Authors: Calderon-Ezquerro Maria del Carmen , Guerrero Parra Adriana , Martinez-Lopez Benjamin
Published: March 2020

Coffee rust is the most destructive disease for coffee crops and the most economically important worldwide. This disease causes the premature fall of the leaves, as well as the weakening of the trees, which translates into significant decreases in the production of coffee beans, representing thus a serious danger for the coffee activity of Mexico, which is the ninth world producer. The aggressiveness of the disease is related to the meteorological conditions that favor, or not, the germination, development, and production of the spores of the fungus causing this disease, as well as its transport in the air inside and outside of the canopy of coffee crops. The objective of this work was to determine the meteorological conditions that modulate the development, release, and transport of spores by using aerobiological methods at two locations with different orographic conditions in the center of the state of Veracruz, Mexico, during the years of 2014 and 2015. In both locations, Pacho Viejo and Teocelo, spores were detected in passive traps placed at 1.5, 3, 6 and 9 meters high, registering the highest concentrations in July and August of both years, coinciding with the period of rainfall decrease known as the Canicula. The spore concentrations in Teocelo increased considerably in 2015, probably due to a decrease in temperature during the months of February and March, which led to preconditioning of the spores favoring their germination in the subsequent months. During July and August 2015, high spore concentrations were present in Teocelo at 9 m high, but not in Pacho Viejo. An analysis of the winds of the region, suggests that wind conditions of 2015 favored the dispersion of the spores above the canopy in Teocelo.
Learning German: The significance of language in a multicultural graduate school
Authors: Held Mirjam , Arruda Ricardo , Chua Allison , Corbalan Ana
Published: March 2020

The HOSST and TOSST transatlantic graduate schools were conceived and designed as multidisciplinary and multicultural training opportunities. While HOSST is headquartered at the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, TOSST is run out of Dalhousie University in Halifax, Canada. English being the language of science, the main language of communication in both programs is English. For most HOSST- and TOSST students, however, English is not their native tongue, but a second or even third language.

Language is a fundamental aspect of any culture; in fact, they are intertwined and mutually influence each other. A culture can only be fully understood through its corresponding language, while interacting with a different language always also illuminates the respective culture. An integral part of the HOSST- and TOSST graduate schools is the requirement that each student spends a 4-month research exchange at the sister institution. For most TOSST students, this meant immersing themselves not only into the German culture but also the German language.

To ease the transition to working and living in Germany, TOSST offered their students a German course, a proposition that was requested by the students and unanimously supported by the TOSST leadership team. Thanks to longstanding relationships with the German community in Halifax, the TOSST German course was offered through the German Heritage Language School. It so happened that the teacher was also a TOSST student. Many students accepted the offer to immerse themselves into a new language and culture ahead of their research exchange. Obviously they did not reach fluency after one or two terms, but studying German prepared them to engage with residents in everyday situations and to better understand the local culture.

Beyond these practical applications, the students appreciated an opportunity for lifelong learning outside of their field of research. Both the students and the teacher found interacting with the German language as part of their work days to foster their creativity by providing a different stimulus than their usual research efforts. The German course further provided an opportunity to build and deepen friendships among TOSST students across cultures and disciplines. The learning not only provided theoretical knowledge of the German culture, but opened up access to the sizeable German community in Halifax. A handful of students even continued with the course after their research exchange was completed as they appreciated studying the German language and culture as a skill that will serve them well beyond the TOSST graduate school.
Forecasting M≥5.0 earthquakes in Italy using a new adaptive smoothing seismicity approach
Authors: Taroni Matteo , Akinci Aybige
Published: March 2020

In this study we present five- and ten-year time-independent forecast of M≥5.0 earthquakes in Italy using only seismicity data, without any tectonic, geologic, or geodetic information. Spatially-varying earthquake occurrence rates are calculated using an adaptive smoothing kernel (Helmstetter et al., 2007) that defines a unique smoothing distance for each earthquake epicenter from the distance to the n-th nearest neighbor, optimized through the Collaboratory for the Study of Earthquake Predictability (CSEP) testing type likelihood methodology (Werner et al.,2007). We modify that adaptive smoothing method to include all earthquakes in the catalog (foreshocks, aftershocks and the events below the completeness magnitude) multiplying each smoothing kernel by a proper scaling factor that varies as function of completeness magnitude and the number of events in each seismic cluster. Our smoothing philosophy relies on the usefulness of all earthquakes, including also those with smaller magnitudes, in forecasting the future seismicity.
The smoothed seismicity Italian model, that provides the forecasted seismicity rates as an expected number of M≥5.0 events per year in each grid cell, 0.1°x0.1°, is constructed by using the complete instrumental catalog, spanning from 1960 to 2019 with a completeness magnitude that decreases with time (from M4.0 to 1.8). Finally, we compare our model with the real observations and with the Italian CSEP experiment models, to check their relative performances, using the official CSEP tests (Taroni et al., 2018). In the present study, the probabilities of occurrence of future large earthquakes in the next 5 and 10 years are calculated based on the assumption that earthquake processes have no memory, i.e., the occurrence of a future earthquake is independent of the occurrence of previous earthquakes from the same source (time-independent model).
Monitoring the last Apennine glacier: recent in situ campaigns and modelling of Calderone glacial apparatus
Authors: Pettinelli Elena , Pecci Massimo , Marzano Frank S. , Biscarini Marianna , Boccabella Paolo , Bruschi Federica , Caira Tiziano , Cappelletti David , Cimini Domenico , D’Aquila Pinuccio , Di Fiore Thomas , Esposito Giulio , Lauro Sebastian E. , Mattei Elisabetta , Monaco Angelo , Palermo Gianluca , Pecci Mattia , Raparelli Edoardo , Scozzafava Marco , Tuccella Paolo
Published: March 2020

The Calderone glacier is at present the most southern glacier in Europe (42° 28' 15’’ N). The little apparatus (about 20.000 m2 in surface area) has been giving an interesting response both to short- and long-term climatic variations which resulted in a considerable reduction in surface area and volume. The glacial apparatus is split into two ice bodies (glacierets) since 2000. The two glacierets are located in a deep northward valley below the top of the Corno Grande (2912 m asl) in the centre of the Gran Sasso d’Italia mountain range (Central Italy). Such glacial apparatus has been subjected to a strong reduction, with a loss of total surface area of about 50% and thickness of about 65%with respect to the hypothetical size (about 105.00 m2 and 55 m at the Little Ice Age).

Since early 90s the Calderone glacier has been subjected to several multidisciplinary field campaigns to monitor and evaluate its role as an environmental indicator in the framework of global warming. Starting from historical series related to more than a century of records, the variability of the different glacier properties has been estimated by using classical geomorphologic methods as well as in situ and remote sensing techniques. In particular, the last field campaigns, in 2015, 2016 and 2019, have been carried out using Ground Penetrating Radar equipped with different antenna frequencies, drone-based survey, snow pit measurements and chemical-physical sampling. The measurement campaigns have been complemented by a regional climate analysis, spanning the last fifty years, and snowpack modelling initialized with microphysical snow data (e.g., snow density, crystal shape and size, hardness).  The snowpack chemical analyses include the main and trace elements, soluble inorganic and organic ions, EC/OC and PAH, with different spatial resolution depending on the analytes. We present here the methodological approach used and some preliminary results.
Influence of nutrients enrichment on ecosystem functioning in a subpolar seagrass meadow
Authors: Pascal Ludovic , Chaillou Gwénaëlle , Bernatchez Pascal , Nozais Christian , Archambault Philippe
Published: March 2020

Seagrass meadows are among the most productive ecosystems in the world: they store a large amount of carbon and host highly diverse macrobenthic communities. They also play a key role in biogeochemistry at the sediment-water interface. The light requirements of seagrasses limit their development to shallow coastal areas where they are facing various natural and anthropogenic disturbances, which has induced a global loss of these ecosystems over the last decades. Nutrient enrichment of coastal waters, resulting from anthropogenic activities is one of the leading causes of this decline. Subpolar seagrass meadows present a strong seasonal dynamic, with a long winter when seagrasses rely on carbon reserves that they build up during the short growing season (limited to two to three months during summer time). Hence, it has been hypothesized that the effects of nutrient enrichment on seagrass ecosystem functioning depend on seasonal dynamics. In this study, we performed a series of mesocosm experiments over a month period to investigate the effects of the timing, duration and intensity of disturbance on macrofauna bioturbation, oxygen and nutrients porewater concentration profiles and benthic fluxes using three levels (including control) of realistic nutrient enrichments at the beginning (June) and at the end (August) of the growing season. In May, effects of intermediate level of nutrient enrichment were only visible on total oxygen uptake by the sediment at day 30 of disturbance while it affected oxygen and nutrients benthic fluxes at day 15 in August. The highest level of nutrient enrichment affected oxygen and nutrients benthic fluxes in May and August. Overall, our results highlight the importance of considering the time (period and duration) in the assessment of the functional consequences of disturbances.
Detecting soil degradation and restoration through a novel coupled sensor and machine learning framework
Authors: Quinton John , James Mike , Davies Jess , Whiting Greg , Nemeth Christopeher , Killick Rebecca , Thomas Evan , Bardgett Richard , Neff Jason
Published: March 2020

In this poster we will outline a new  ambitious cross-disciplinary project focused on detecting soil degradation and restoration through a novel multi-functional soil sensing platform that combines conventional and newly created sensors and a machine learning framework. Our work  aims to advance our understanding of dynamic soil processes that operate at different temporal/spatial scales. Through the creation of an innovative new approach to capturing and analyzing high frequency data from in-situ sensors, this project will predict the rate and direction of soil system functions for sites undergoing degradation or restoration. To do this, we will build and train a new mechanistically-informed machine learning system to turn high frequency data on multiple soil functions, such as water infiltration, CO2 production, and surface soil movement, into predictions of longer term changes in soil health including the status of microbial processes, soil organic matter (SOM) content, and other properties and processes. Such an approach could be transformative: a system that will allow short-term sensor data to be used to evaluate longer term soil transformations in key ecosystem functions. We will start our work with a suite of off-the-shelf sensors observing multiple soil functions that can be installed quickly. These data will allow us to rapidly initiate development and training of a novel mechanistically informed machine learning framework. In parallel we will develop two new soil health sensors focused on in-situ real time measurement of decomposition rates and transformation of soil color that reflects the accumulation or loss of SOM. We will then link these new sensors with a suite of conventional sensors in a novel data collection and networking system coupled to the Swarm satellite network to create a low cost sensor array that can be deployed in remote areas and used to support studies of soil degradation or progress toward restoration worldwide.
Machine learning as supporting method for UXO mapping and detection
Authors: Henkel Daniela , González Ávalos Everardo , Kampmeier Mareike , Michaelis Patrick , Greinert Jens
Published: March 2020

Marine munitions, or unexploded ordnances (UXO), were massively disposed of in coastal waters after World War II; they are still being introduced into the marine environment during war activities and military exercises. UXO detection and removal has gained great interest during the ongoing efforts to install offshore wind parks for energy generation as well as cable routing through coastal waters. Additionally, 70 years after World War II munition dumping events, more and more chemical and conventional munition is rusting away increasing the risk of toxic contamination.

The general detection methodology includes high resolution multibeam mapping, hydroacoustic sub-bottom mapping, electromagnetic surveys with gradiometers as well as visual inspections by divers or remotely operated vehicles (ROVs). Using autonomous unmanned vehicles (AUVs) for autonomous underwater inspections with multibeam, camera and EM systems is the next technological step in acquiring meaningful high resolution data independently of a mother ship. However, it would be beneficial for the use of such technology to be able to better predict potential hot spots of munition targets and distinguish them from other objects such as rocks, small artificial constructions or metallic waste (wires, barrels, etc.).

The above-mentioned predictor layers could be utilized for machine learning with different, already existing, and accessible algorithms. The structure of the data has a high similarity to image data, an area where neural networks are the benchmark. As a first approach we therefore trained convolutional neural networks in a supervised manner to detect seafloor areas contaminated with UXO. For this we manually annotated known UXO locations as well as known non-UXO locations to generate a training dataset which was later augmented by rotating and flipping each annotated tile. We achieved a high accuracy with this approach using only a subset of the data sources mentioned above as input layers. We also explored the use of further input layers and larger training datasets, and their impact in performance. This is a good example for machine learning enabling us to classify large areas in a short time and with minimal need for manual annotation.
Spatio-temporal variations of source parameters in the nucleation zone of the 6 April 2009, Mw 6.1 L'Aquila Earthquake
Authors: Di Giovambattista Rita , Calderoni Giovanna , Rovelli Antonio
Published: March 2020

We present the results of Brune stress drop (∆σ) and apparent stress (τa) variability of  earthquakes located in a small zone adjacent to the hypocenter of the damaging Mw 6.1 L'Aquila earthquake. Their magnitude ranges between  2.7 and 4.1. Interevent variability of stress drop and apparent stress results in a factor of 10, well beyond the individual‐event uncertainty. Radiation efficiency ηsw = τa/∆σ varies mostly between 0.1 and 0.2, but decreases in the days immediately before and after the main shock to values as low as 0.06. This may be related to the migration of the events occurring in those days into a focal volume with higher dynamic strength. The temporal change of ηsw might be interpreted as a spatial variation due to the earthquake migration into the locked portion of the fault originating the main shock. Furthermore, no variation in stress drop and apparent stress can be observed between foreshocks and aftershocks but the smallest and largest ∆σ result in a good correlation with the largest and smallest b‐values respectively, as already documented in literature in the rupture nucleation volume of large earthquakes.
A relationship between repiquetes, rainfall and circulation low-level wind regimes over the Andean-Amazon river basin
Authors: Figueroa Manuel , Armijos Elisa , Espinoza Jhan-Carlo , Ronchail Josyane , Fraizy Pascal
Published: March 2020

Riparian farmers along the Peruvian Amazon River face hydrological events and poor soil conditions that put their low-land crops on high risk of production loss during the flood recession period. One of those hydrological events is a sudden reversal on the river stage known as “repiquete”, which have been poorly studied in terms of its origins. This work analyzes the hydro-meteorological mechanisms over the Andes-Amazon river basins that could produce repiquetes near Iquitos city in Peru. Repiquetes were defined and characterized for the 1996-2018 period by using river stage data from three hydrological gauging stations at Amazon, Marañón and Ucayali rivers. Furthermore, daily rainfall from high spatial resolution CHIRPS (0.05° and 0.25) and TRMM (0.25) data, as well as, daily low-level winds at 850 hPa from ERA-Interim are used to characterize rainfall and large-scale atmospheric patterns associated with repiquetes. Considering that 73 significant repiquetes (reversal > 20cm) occurred in Amazon River, 64.4% of them are preceded by repiquetes only in the Marañón River, 5.5% are preceded by repiquetes only in the Ucayali River, 20.5% are preceded by repiquetes on both rivers and the rest only registered in Amazon River without precursor defined. These results show that the main precursor of repiquetes in Amazon River is the Marañón River. Most of repiquetes are associated with abundant rainfall over the Peruvian and Ecuadorian Andes-Amazon transition region with a remarkable change of northerly winds to southerly winds regime and an easterly flow during five to three days before the beginning of repiquete in Amazon River.
GLImER: a MATLAB-based tool to image global lithospheric structure
Authors: Rondenay Stéphane , Sawade Lucas , Makus Peter
Published: March 2020

Project GLImER (Global Lithospheric Imagining using Earthquake Recordings) aims to conduct a global survey of lithospheric interfaces using converted teleseismic body waves. Data from permanent and temporary seismic networks worldwide are processed automatically to produce global maps of key interfaces (crust-mantle boundary, intra-lithospheric interfaces, lithosphere-asthenosphere boundary). In this presentation, we reflect on the challenges associated with automating the analysis of converted waves and the potential of the resulting data products to be used in novel imaging approaches. A large part of the analysis and the visualization are carried out via MATLAB-based applications. The main steps of the workflow include signal processing for quality control of the input data and earthquake source normalization, mapping of the data to depth for image generation, and interactive 2-D/3-D plotting for visualization. We discuss how these various tools, especially the visualization ones, can be used for both research and education purposes.
Field studies for detecting microplastic in environmental compartments and a novel tomography approach for analysis of undisturbed soil or sediment cores
Authors: Oswald Sascha , Schmidt Lena Katharina , Bauer Eva , Tötzke Christian
Published: March 2020

In recent years we all had to realize that plastics has not only been accumulating in the oceans, but as microplastics also has entered surface waters, soils and partly organisms in large numbers. Thus, as with other pollutants in the environment in the past, we need detection and monitoring methods for quantifying their distribution, fate and pathways. By that we can better understand where they are emitted, where they are present and what are the key mechanisms they undergo. However, this means a new challenge and need for novel approaches because they are different to other pollutants.  In one study we have monitored presence of microplastic particles and some of their properties in a surface water course and groundwater wells close the river banks, detecting them by a novel and fast imaging technique after processing of surface water samples. Furthermore, soil and sand samples from different places were separated by density and then manually analyzed, and the results indicated an extensive presence of microplastic particles. Finally, we have developed a tomography approach to detect microplastic particles also in undisturbed sandy soil or sediment samples. This has the advantage that cores can be taken and analyzed that show the real distribution of microplastic particles, and obtain also some information on their size and shape. Overall, this also can contribute to understand their deposition and displacement in the past. We will demonstrate how a combination of X-ray and neutron tomography could be used to identify microplastic particles non-invasively, for test samples as well as first environmental samples.
The North Pacific in Warm(ing) Climates: effects on ocean circulation and biogeochemical cycles
Authors: Lembke-Jene Lester , Tiedemann Ralf , Nürnberg Dirk , Gong Xun , Zou Jianjun , Chao Weng-si (JC) , Shi Xuefa , Lohmann Gerrit
Published: March 2020

The North Pacific hosts the both one of the largest oceanic reservoirs of sequestered carbon and extensive oxygen minimum zones in the world ocean, which will likely intensify and expand under future climate warming scenarios, yielding significant consequences for ecosystems, biogeochemical cycles, and living resources. At present, relatively better-oxygenated subsurface North Pacific Intermediate Water (NPIW) mitigates OMZ development, but on instrumental time scales, data the past decades indicate decreasing NPIW ventilation, induced by a freshening and increased stratification of surface and thermocline waters. Longer variations in these oceanographic boundary conditions were, however, large and are thus able to hinder assessment of anthropogenic influences against natural background shifts. We previously provided evidence modern well-ventilated waters underwent significant millennial-scale variations over the last ca. 12,000 years (Lembke-Jene et al., 2018), with a prominent “tipping point” around 4,500 years before present.Crossing such mid-Holocene threshold led to the Okhotsk Sea becoming the modern ventilation source it is today, although the underlying forcing and physical boundary conditions characteristics remain largely enigmatic. A combination of sea ice loss, higher water temperatures, and remineralization rates may be able to induce a nonlinear change into a different mean state in this region. To constrain these factors we present combined surface, mesopelagic and bathyal ocean proxy records from key study sites in the Western Subarctic Pacific, the Okhotsk Sea and Bering Sea, and the Gulf of Alalska, with submillennial-scale resolution to assess changes in upper ocean stratification, nutrient characteristics and resulting changes on mid-depth water ventilation. Our results imply that under assumed past hemispheric warmer- than-present conditions, regional surface temperatures and upper ocean stratification were increased and changed in a nonlinear mode during the last 4-5,000 years, associated with changing primary productivity patterns and biogeochemical feedback mechanisms. Results from complementary Earth System Model simulations provide evidence for the interaction between the high-latitude North Pacific marginal seas and thePacific Western Subarctic Gyre circulation, with effects on mesopelagic ventilation dynamics and its consequences for large oceanic regions.
Are modern chemosynthesis-based communities a ‘glimpse of antiquity’? The changing fate of bivalves and brachiopods at ancient methane seeps as recorded in the Middle Palaeozoic of Morocco
Authors: Jakubowicz Michał , Hryniewicz Krzysztof
Published: March 2020

Despite much scientific effort aimed over the past three decades to better constrain the fossil record of chemosynthesis-based communities, our understanding of their early evolution remains fragmentary. Until recently, a dominant perception was that, unlike the Cenozoic, bivalve-dominated chemosynthetic ecosystems, the Paleozoic to mid-Mesozoic methane seeps and hydrothermal vents were dominated by brachiopods. Similarly, the pattern of brachiopod vs. bivalve predominance at seeps and vents over the Phanerozoic was believed to have crudely followed that observed in normal-marine benthic shelly assemblages. Recent discoveries from the Middle Palaeozoic of Morocco have questioned this simple perception, documenting the presence of late Silurian and Middle Devonian seeps dominated by mass accumulations of large, semi-infaunal, modiomorphid bivalves (Hryniewicz et al., 2017; Jakubowicz et al., 2017). While representing a lineage unrelated to modern seep-obligate bivalve taxa, the mid-Palaeozoic seep bivalves developed a set of morphological adaptations strikingly similar to those of their modern ecological counterparts, and formed analogous, densely-packed, nearly monospecific assemblages, both suggesting their chemosymbiotic lifestyle. The new documentation of Palaeozoic establishment of the bivalve-dominated seep communities provides a fresh look at the concept of modern chemosynthetic ecosystems as a 'glimpse of antiquity', showing that although it is largely not true taxonomically, it clearly is in terms of recurring morphological themes. At the same time, this refined Palaeozoic record makes the factors responsible for the apparent scarcity of seep-related bivalves during the upper Devonian to early Mesozoic, a period of the remarkable success of brachiopod-dominated seep assemblages, ever more enigmatic.
Widespread underestimation of the danger of groundwater contamination by shortcuts into aquifers
Authors: Hartmann Andreas , research consortium The karst vulnerablity
Published: March 2020

Groundwater pollution threatens human and ecosystem health in many areas around the globe. Shortcuts to the groundwater through enlarged cracks and fissures, often referred to as concentrated recharge, are known to transmit short-lived pollutants into carbonate aquifers endangering water quality of around a quarter of the world population. However, the large-scale impact of concentrated recharge on water quality remains poorly understood. Here we apply a continental-scale model to quantify for the first time the danger of groundwater contamination by degradable pollutants through concentrated recharge in carbonate rock regions. We show that concentrated recharge is the primary reason for the rapid transport of contaminants to the groundwater, increasing the percentage of non-degraded pollutants from <1% in areas without concentrated recharge to around 20-50% in areas where concentrated recharge is present. Our findings are most pronounced in the Mediterranean region where agricultural pollutants in groundwater recharge like Glyphosate can exceed allowed concentrations by up to 19 times. Our results imply that in regions where shortcuts to the groundwater exist, continuing industrial agricultural productivity to optimize food production may result in a widespread reduction of available drinking water and harm ecosystem services more intense than presently available large-scale modelling concepts suggest.
Solar System Missions in the ESA Scientific Program
Authors: Hasinger Günther
Published: March 2020

After the successful outcome of the Space19+ ministerial meeting in Seville we are looking forward to exciting years, with important new missions in the ESA Scientific Programme. Solar Orbiter in Spring 2020, the Exomars Rover in Summer 2020 and JUICE in Summer 2022 are flagship ESA missions in the Cosmic Vision programme. But there are also a number of smaller and missions of opportunity, like Proba-3 in 2021, the ESA/China mission SMILE in 2023, and JAXA Martian Moon Explorer mission MMX in 2024. And in 2028 there will be the exciting Flexi mission Comet Interceptor to an as yet undiscovered pristine comet or even another interstellar visitor. I will review these missions together with the exciting science from our current fleet of solar system missions.
Epidote dissolution and its role within carbon storage
Authors: Marieni Chiara , Saldi Giuseppe , Benezeth Pascale , Oelkers Eric
Published: March 2020

In the past 20 years, basaltic aquifers have been studied as a key geologic carbon storage host due to their high reactivity and widespread distribution. However, many basaltic reservoirs contain substantial alteration minerals and their potential as cation sources for carbon mineralization processes still need to be assessed. A common alteration phase in high temperatures (≥ 200 °C) basalts is epidote. To help determine the possible contribution of this mineral to CO2 sequestration through the release of its constituting cations, the dissolution rates of epidote from the Green Monster Mine (Alaska) were experimentally measured. Far-from equilibrium experiments were conducted over the pH range 2-11 using both batch reactors at 25 °C, and mixed-flow reactors at 100 and 200 °C. Furthermore, mixed-flow reactor experiments at pH ~9 on epidote in presence of CO2 were carried out at 200 °C to study its carbonation potential and to quantify the yields of this reaction compared to basaltic glass. The determination of the extent of this process was monitored by inorganic carbon analyses on both solid and fluid fraction using non-dispersive infra-red (NDIR) CO2 gas analyses. Preliminary results suggest that epidote and potentially other alteration Ca-silicate phases can provide Ca2+ as efficiently as fresh basalts at 25 and 100 °C to promote the precipitation of calcium carbonate. Further experimental and modelling work is ongoing to confirm these findings at different thermal conditions and as a function of injected fluid chemistry.
The Icy Giants & Triton’s Ionospheres – lessons learned from Cassini observations within Saturn’s and Titan’s ionospheres
Authors: Wahlund Jan-Erik , Morooka Michiko W. , Andrews David , André Mats , Bergman Jan , Edberg Niklas , Eriksson Anders I. , Hadid Lina , Khotyaintsev Yuri , Vaivads Andris , Vigren Erik
Published: March 2020

We discuss the importance to determine the structure and composition of the upper atmospheres and ionospheres of the Icy Giants (Uranus & Neptune) as well as Triton’s ionosphere in the light of numerous recently obtained Cassini results. The ionizing radiation and charging environment within the upper atmospheres of Saturn and Titan creates a very complex organic chemistry leading to charged sub-nm-sized to 100 nm-sized aerosols. The charged dust has a profound effect on the ionospheric structure and related chemistry, enhancing the ion number density well above photochemical equilibrium levels, while the electrons tend to become attached to the dust population. The organic chemistry leads to compounds reaching above 50,000 amu diffusing downward and possibly creating a pre-biotic chemistry. This process, involving nitrogen, methane and water may very well be a more general process, also applicable for the cases of Uranus, Neptune and Triton, were all have these starting species abundant in their upper atmospheres. We therefore propose that a future mission to the Ice Giants and the moon Triton has Langmuir probe, electron spectrometer, dust, ion- and neutral mass spectrometers onboard to make detailed in-situ measurements on both the orbiter and atmospheric probe in order to investigate this fundamental chemistry and aerosol formation.