bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Seismo-Electromagnetic signals in an area characterized by an intense hydrothermal activity: a case study from the Solfatara area (Campi Flegrei, Italy)
Authors: Siniscalchi Agata , Balasco Marianna , Romano Gerardo , Tripaldi Simona
Published: March 2020

In 2014 t In the framework of the MEDSUV project, the Solfatara area, part of the Campi Flegrei caldera, was chosen as test site for the RICEN (Repeated InduCed Earthquakes and Noise) experiment mainly oriented to the use of seismic waves (both in passive and active mode) as a diagnostic tool to investigate the changes in the properties of the medium at small scales. Besides the study of seismic waves (both in passive and active mode), part of the RICEN activities was focused on the detection and characterization of the Seismo-Electromagnetic signals (SES) associated with their propagation.

Considering the abundance of fluids that characterize the shallow hydrothermal system of Solfatara area, SES arewere expected to be detectable and informative of the subsoil structure. On May 2014, Hence for their detection during RICEN experimthree magnetotelluric (MT) stations were installed outside the seismic grid and close to the main volcanic fumaroles in the Solfatara area. Thusing electrical and magnetic components concurrently with seismic and geochemical measurements were recorded. As a result, SES related to Vibrosesis seismic source energization in 100 sites, distributed on an almost regular grid on an area of about 115m x 90m, were analyzed. The m.

Although Unfortunately the electrical part of the SES could not be extracted by the recorded time series due to the severe effects of the Solfatara volcanic environment on the unmpolarizable electrodes. ,Converselyagnetic components, instead of the electrical ones, were generally better appreciable, in terms of amplitude, with respect to the natural electromagnetic fluctuations(s?). This circumstance allowed to verify the strict causality relationship between of the SES with and seismic signals for interstation distances (Seismic source -MT stations) ranging between 100 m and 200 m..

Focusing on the magnetic part, a comparative Wavelet analysis on SES and on seismic source permitted to evaluate that in the time domain that SES signals are mainly associated with Rayleigh wave, due to relatively large average distance between shot and MT sites, ranging between 60 m and 200 m.

Once defined SES characteristics, in terms of frequency content and amplitude, possible information on the subsurface status and new inferences on fluids characterizing the subsoil of the studied area were obtained. This was possible by investigating the spatial distribution of SES amplitude and by comparing it with 3D model of Vp, Vs and resistivity as well as with temperature and CO2 flux maps.
Root development under fluctuating soil physical stress – plastic and elastic responses
Authors: Colombi Tino , Sjulgård Hanna , Iseskog Daniel , Keller Thomas
Published: March 2020

Physical properties of soil such as penetration resistance and oxygen concentration of soil air strongly influence root system development in plants. Soils typically exhibit considerable spatial and temporal fluctuations in penetration resistance and oxygen concentration of soil air due to wetting-drying cycles, small-scale differences in soil compactness or hotspots of biological activity. Hence, roots of a single plant are exposed to different physical environments and thus physical stresses during their growth through the soil profile. Plants are known to adjust their root development to these spatiotemporal fluctuations in soil physical conditions. Such phenotypic adjustments include changes of root growth rate as well as alterations of root morphology and anatomy. However, these adjustments reduce accessibility of water and nutrients and may increase the carbon demand for soil exploration, which limits aboveground plant development. Until now, it is unclear whether such adjustments in root development are plastic (i.e. the phenotype is irreversibly changed even when roots re-enter zones with optimal growth conditions) or elastic (i.e. the phenotype is only temporarily changed and recovers again when roots re-enter zones with optimal growth conditions).

To investigate the plasticity and elasticity of root development, we designed customized microrhizotrons in which soil penetration resistance and the concentration of oxygen in soil air can be varied. Near-infrared (λ=830 nm) time-lapse imaging was applied to quantify root growth rates, and combined with measurements of root morphology and anatomy. A series of experiments was conducted using different crop species with contrasting root system properties (fibrous vs. taproot system, thin vs. thick roots). After an establishment period of three days under optimal growth conditions, roots were exposed for 24 hours to increased penetration resistance, hypoxia and the combination of both stresses. Following this, the stress was released, and plants continued to grow for 24 hours at optimal conditions, before a second stress was applied for another 24 hours. Generally, root development responded to changes in soil physical conditions across all species. However, depending on the species, the adjustments in root development were found to be constant or temporary, i.e. plastic or elastic. This difference between species was particularly pronounced for root growth rate. Root growth rate in pea recovered after soil physical stress was released, while root growth rate in wheat remained low after stress release. The obtained findings will be discussed with respect to the tolerance of different plants to soil physical stress as well as the effects of root growth on soil structure dynamics.
Retrieval of hyperspectral CDOM absorption with integrating cavity sphere
Authors: Vellucci Vincenzo , Golbol Melek , Antoine David
Published: March 2020

Typical measurements of the absorption coefficient of the chromophoric fraction of dissolved organic carbon (CDOM) are performed on filtered seawaters samples. Though samples could be stored in the dark at 4° for up to 6 months, it is preferable to analyse them within 24 hours from collection as variation of absorption might occur depending on the nature of the sample, and to minimize the effect of possible contamination.

As it is not always practical to analyse samples on board, techniques have been proposed to measure the CDOM with in situ deployed reflective tube absorption meters (i.e. SeaBird ac-9 and ac-s). These techniques allow time effective measurements of CDOM at high vertical resolution. However the typical path-length of the cavity containing the water sample is of 0.25 m, i.e. one eighth of most common protocols used in laboratory analyses, thus limiting the accuracy of the measurements at lower signals.

Integrating cavity absorption meters (ICAM) represent an alternative to reflective tube absorption meters. They have been primarily developed to reduce the effect of scattering of particulate onto absorption measurements. Nonetheless this technique presents also the advantage to increase the effective optical path-length of the light beam due to multiple reflections into the reflecting cavity (up to 2 m for a 10 cm sphere diameter). This peculiarity make ICAM suitable for applications with lower signal such as open ocean case I waters.

Here we present some advances toward the definition of a protocol for the use of a hyperspectral integrating cavity sphere (Hobilabs a-sphere) for the in situ measurement of CDOM. In particular we address aspects related to cleaning, blank measurements, water flow into the cavity and pressure and we present data from the BOUSSOLE bio-optical time series (NW Mediterranean Sea).
Towards improving radiometry-derived snow depths with SNOWPACK and SMRT
Authors: Mallett Robbie , Stroeve Julienne , Tsamados Michel , Liston Glen
Published: March 2020

The depth of overlying snow on sea ice exerts a strong control on atmosphere-ocean heat and light flux and introduces major uncertainties in the remote sensing of sea ice thickness. Satellite-mounted microwave radiometers have enabled retrieval of snow depths over first year ice, but such retrievals are subject to a wide margin of error due to spatial variation in snow stratigraphy and roughness.

Here we model the microwave signature of snow on sea ice using a recently released sea ice variant of the snowpack evolution model, SNOWPACK (Wever et al., 2020). By advecting parcels of sea ice using ice motion vectors and exposing them to the relevant atmospheric forcing using ERA5 reanalysis, we model the accumulation of snow and the development of snowpack stratigraphy.

We then pass these modelled snowpacks to the Snow Microwave Radiative Transfer model (Picard et al., 2018) to estimate their microwave emission characteristics. By using relationships from the literature relating the ratios of the 37GHz and 19GHz channels, we calculate whether the traditional “gradient ratio” method (Markus and Cavalieri, 1998) over- or underestimates the depth of snow at a particular point based on our modelling. We then adjust the observed gradient ratio based on the model results in an attempt to better characterise snow depths.

 

References

Wever, Nander, et al. "Version 1 of a sea ice module for the physics-based, detailed, multi-layer SNOWPACK model." Geoscientific Model Development 13.1 (2020): 99-119.

Picard, Ghislain, Melody Sandells, and Henning Löwe. "SMRT: An active–passive microwave radiative transfer model for snow with multiple microstructure and scattering formulations (v1. 0)." Geoscientific Model Development 11.7 (2018): 2763-2788.

Markus, Thorsten, and Donald J. Cavalieri. "Snow depth distribution over sea ice in the Southern Ocean from satellite passive microwave data." Antarctic sea ice: physical processes, interactions and variability 74 (1998): 19-39.
T’ephra Bag citizen science project: initial findings
Authors: Kwasniewska Kamila , Lacchia Anthea , Schuitema Geertje , McElwain Jennifer
Published: March 2020

We report the initial findings of the ‘T’ephra Bag citizen science project, a one-year pilot study that commenced in October 2019. This initiative, which is directed at primary school students and their families, aims to test the chemical weathering potential of tephra (volcanic ash) when buried in a pot of local soil and planted with a common grass species. A parallel aim is to raise awareness among participants of the potential of geological-based solutions for climate change through the reduction of carbon dioxide (CO2) concentration in the atmosphere. A second aim of the project is to investigate participants’ perceptions of climate change and carbon emission reduction technologies and to test the effectiveness of such citizen science initiatives in changing the attitudes and perceptions of school children. 
Expert and novice gaze in seismic interpretation, implications for colour palette choice and learning.
Authors: Bond Clare , Tatler Ben
Published: March 2020

Remotely sensed seismic images are our main window into sub-surface geology and are used extensively in industries that explore or exploit the sub-surface and it’s geo-resources. Seismic image data are made by bouncing sound waves off sub-surface rock layers to build a picture of the geology. Seismic imagery, has an inherent uncertainty derived from image resolution, processing and acquisition workflows; the interpreting geologist therefore has a crucial role in using information in the image to produce a realistic geological model on which multi-billion dollar and key environmental decisions can be made. Research has shown that experts look at such imagery differently to novices and that colour presentation and other factors influence response to an image. Here we investigate how such factors influence a geologists’ interpreting a seismic image, and consider if we can use our findings to improve future seismic image interpretation through expert learning and potential image enhancement.

Eye movements offer a valuable, unbiased, research method, to reveal not only an individual’s interests and priorities when viewing an image, but also their expertise. In other disciplines eye movements of experts have been used to improve skill and enhance training of novices.Here we use eye-tracking to capture where geologists’ look on a seismic image to investigate whether: 1) colour palette choice for image presentation can affect image perception and influence gaze and 2) if expert and novice gaze patterns are different. In our experiments we have considered multiple colour palettes for a range of seismic imagery containing structural and sedimentological features. We show that expert and novice gaze is different, particularly in the initial phase of image exposure and that colour palettes have a significant impact on gaze and attention of all participants. Ultimately the objective is to see if we can learn from expert gaze to help improve the seismic interpretation skills of novices through image enhancement, and ultimately image interpretation outcome.
Impacts of heat stress on the calcifying fluid chemistry and trace element composition of corals from thermally variable reefs
Authors: Schoepf Verena , D'Olivo Juan-Pablo , Rigal Cyrielle , Jung Maria , McCulloch Malcolm
Published: March 2020

Coral reefs are increasingly threatened by climate change and mass bleaching events. Predicting how corals will respond to rapid ocean warming requires a better understanding of how they have responded to environmental change in the past – information that can be reconstructed from coral skeletal records. However, significant knowledge gaps remain in our understanding of how coral biomineralization and the incorporation of geochemical tracers is impacted by heat stress and bleaching, particularly since the physiological status of corals used for reconstruction of past stress events is often unknown. Using boron-based geochemical tracers (δ11B, B/Ca), we investigated how heat stress caused by a marine heatwave impacted the carbonate chemistry of the coral calcifying fluid as well as skeletal trace element composition in the branching coral Acropora aspera. Importantly, we recorded in situ temperature and coral health status during the bleaching event and after 7 months of recovery. We show that heat-stressed Acropora corals continued to upregulate the pH of their calcifying fluid (cf); however, dissolved inorganic carbon upregulation inside the cf was significantly disrupted by heat stress. Similarly, we observed suppression of the typical seasonality in the temperature proxies Sr/Ca, Mg/Ca, Li/Ca and Li/Mg, likely due to a combination of reduced growth rates, disruption of key enzymes involved in calcification and Rayleigh fractionation. Anomalies in TE/Ca ratios were still observed 7 months after peak bleaching, even though symbiont densities and chlorophyll a concentrations were fully restored at this point. Interestingly, the response to heat stress did not differ between the thermally variable intertidal and the thermally more moderate subtidal environments whose coral populations are known to have a different heat tolerance, nor between colonies with varying degrees of bleaching. Our findings suggest that coral biomineralization mechanisms are highly sensitive to heat stress, and that the biogeochemical stress response of branching Acropora corals is remarkably consistent with that of massive Porites corals.
Io’s auroral footprints: MHD simulations of the interaction between Io and Jupiter
Authors: Schlegel Stephan , Saur Joachim
Published: March 2020

The electromagnetic interaction between Jupiter and its innermost Galilean moon Io is a prime example for moon-planet and star-planet interaction. A very striking feature is the Io Foot Print (IFP) in Jupiter’s upper atmosphere. With the Juno spacecraft orbiting Jupiter, new insights about the complex structure of the IFP have been achieved which can not be fully explained by existing models. A deeper understanding is necessary to explain these Juno observations [Mura et al. 2018, Szalay et al. 2018]. For that purpose a simulation of the system with the single fluid MHD-Code Pluto is set up to study the Alfvén wing generated by Io in detail. In our study, we use a model similar to Jacobsen et al. 2007 with a constant magnetic field and spatially varying density. Then we increase the complexity of this model by including a more realistic wave generator, i.e. Io, and a more complex model of the Jovian inner magnetosphere.
Conceptualizing trade-offs of water conservation strategies and unintended consequences using a system dynamics approach
Authors: Odongo Vincent , Di Baldassarre Giuliano , Mazzoleni Maurizio
Published: March 2020

Improving water use efficiency in agriculture is a key strategy in reducing water scarcity, especially during drought seasons. However, the benefits of these water saving strategies can be reduced if farmers switch to more profitable and water consuming crops or increasing irrigable area, i.e. rebound effects. These feedbacks will likely offset the water savings benefits and subsequently intensify agricultural water use. Here we propose a new system dynamic model that represents the interactions and feedback loops between hydrological and social processes to explore rebound effects by analysing competing water needs for both urban and agricultural allocation. The model is then used to explore the dynamics of different mitigation policy options to alleviate the phenomenon: (i) Restricting water allocation (ii) Limiting size of agricultural land (iii) Changing cropping patterns (iv) Deficit irrigation.

 
Contribution of the carbon sources involved in latex regeneration in rubber trees (Hevea brasiliensis): an in situ 13CO2 labelling experiment
Authors: Desalme Dorine , Duangngam Ornuma , Thaler Philippe , Kasemsap Poonpipope , Sathornkich Jate , Satakhun Duangrat , Chayawat Chompunut , Angeli Nicolas , Chantuma Pisamai , Epron Daniel
Published: March 2020

Rubber trees (Hevea brasiliensis) are the main source of natural rubber, extracted from latex, which exudes from the trunk after tapping. Tapped trees require large amounts of carbon (C) to regenerate the latex after its collection. Knowing the contribution of C sources involved in latex biosynthesis will help understand how rubber trees face this additional C demand. Whole crown 13CO2 pulse labelling was performed on 4-year-old rubber trees in June when latex production was low and in October, when it was high. 13C contents were quantified in the foliage, phloem sap, wood and latex. In both labelling periods, 13C was recovered in latex just after labelling, indicating that part of the carbohydrates was directly allocated to latex. However, significant 13C amounts were still recovered in latex after 100 days and the peak was reached significantly later than in phloem sap, demonstrating the contribution of a reserve pool as a source of latex C. The contribution of new photosynthates to latex regeneration was faster and higher when latex metabolism was well established, in October than in June. An improved understanding of C dynamics and source-sink relationship in rubber tree is crucial to adapt tapping system practices and ensure sustainable latex production.
Vicoforte sandstone in Cultural Heritage
Authors: Marini Paola , Bellopede Rossana
Published: March 2020

The large family of sandstone covers stones with different grains, porosity, cement or matrix, compactness, chemical composition etc. and it is widely used as cladding stone, even in historic buildings. From literature, its decay is usually connected to the action of salts or to black crusts because of pollution.

Being sandstone a sedimentary rock deposited in layers, often the quarry produce material with a high variability in aspects and mechanical properties. This can be also evident in the resistance to decay shown in the monuments that is typical of each facies though it has been exposed for the same lapse of time and under similar climatic conditions. This is the case of Arenaria di Vicoforte used on the facade of the Vicoforte Sanctuary (Vicoforte - Mondovì) and probably on the external pilaster of the Monte dei Cappuccini church in Turin. Both the catholic monuments were designed by architect Ascanio Vitozzi at the end of the XVI century . It is possible to compare the high degree of weathering of the pilasters  of the Monte dei Cappuccini church with the good ageing behaviour shown by the Vicoforte Sanctuary sandstone.

Different durability tests were carried out: resistance to salt crystallisation, resistance to ageing due to SO2 action in the presence of humidity, frost resistance. The mass weight difference, method used to evaluate the forecast of decay in various european standardardized methodologies, does not always offer a satisfactory estimation of the decay of stone after salt crystallization while water absorption, which is well correlated to the physical mechanical characteristics of the stone, together with a visual inspection, is a good index of the decay in order to obtain a distinction, in terms of durability, between different sandstones even of a same geological district.

A visit to the quarry solved any doubts: two different facies of the Vicoforte sandstone were quarried, one yellowish and the other grey. The first, mainly silicatic, was used for the Sanctuary near the quarry, the grey one (with a carbonate content of 18%) could be the one sent to Turin.

The variability of the rock characteristics in the quarry should therefore be taken into account when evaluating the durability of the sandstone.
Induced polarization and transient electromagnetic surveys for the characterization of a graphite ore
Authors: Flores Orozco Adrian , Aigner Lukas , Katona Timea , Bücker Matthias , Zehetgruber Philipp , Römer Alexander
Published: March 2020

The prospection of electrical conductors and semi-conductors has been one of the classical applications of the induced polarization (IP) method, with recent laboratory studies permitting to gain a deeper insight into the parameters controlling the polarization response. However, the application of electrochemical models developed for laboratory measurements has been rarely taken into field-scale imaging data sets. To fill this gap, here we discuss IP imaging results collected in Zettlitz (Austria), a former quarry operated between 1855 and 1967 for the extraction of graphite, an electrical conductor. The general goal of the geophysical survey is to characterize the geometry and volume of the residual graphite at the site. To this end, frequency-domain IP imaging measurements were collected along 10 main transects using different geometries, with selected data sets collected in the frequency range between 0.25 and 1 Hz to gain information about the frequency-dependence of the electrical properties. As expected, initial measurements revealed a high IP response in the graphite-rich areas. Nevertheless, the high electrical conductivity of the materials resulted in low voltage readings and an important decrease in the signal-to-noise ratio for deep measurements; thus, significantly reducing the depth of investigation. To overcome this limitation, we conducted measurements at areas of interest using transient electromagnetic (TEM) soundings, which are favored by the high conductivity of the targeted graphite and permit a better delineation of the contact to the calcareous host-rock. Initial analysis of the TEM data revealed a poor consistency with the electrical models retrieved from the IP surveys. However, taking into account the IP effect within the inversion of the TEM data significantly improved the consistency in the subsurface models resolved by the different methods. In order to resolve for adequate parameters for the modeling of TEM signatures, IP measurements were also collected at relevant positions in the frequency-range between 0.01 and 10000 Hz, with a high accuracy electrical impedance spectrometer. Further IP measurements were also collected in rock samples in the laboratory to aid in the interpretation of the field surveys and to permit the numerical modeling of the electrical signatures using a recently proposed electrochemical model. Our results demonstrate that the combination of IP and TEM surveys provide an improved modeling of the field signatures and, thus, a better characterization of the site. Additionally, we discuss the applicability of existing empirical and numerical models for the quantitative interpretation of field surveys.
A numerical study of dust particle effects on cloud microphysical processes and hail/precipitation impacts
Authors: Chaniotis Ioannis , Patlakas Platon , Kallos George
Published: March 2020

The effects of natural aerosols on microphysical processes in clouds are quite important for their development and evolution and still pose some unresolved questions on the impact they have in the atmosphere and climate. The processes where they interfere, can lead to an uncertainty in the intensity of precipitation and the hydrometeor species as well as the temporal and spatial extent of the affected areas. Apart from the scientific interest of such studies, the outcome highly affects applications and early warning systems associated to water management,  food security and agriculture.

For the needs of the study, the state of the art atmospheric modeling system RAMS-ICLAMS was used to investigate the effects of desert dust concentrations on microphysical processes in clouds. The model is able to run in very high resolutions in order to resolve cloud processes explicitly. Extreme case studies were selected, simulated and the model performance was evaluated showing satisfactory results. Sensitivity tests were performed in order to quantify the direct, indirect and semi-direct impact of CCN and IN concentrations. These tests showed notable effects on the cloud microphysical processes, as well as on hydrometeors. This further enhances the need for a more accurate description of aerosol feedbacks in regional and climate atmospheric models.
Impacts of sand extraction and deposition on the ecosystem recovery rate in the southern coastal zone of Portugal
Authors: Drago Teresa , Taborda Rui , Teixeira Sebastião , Rosa Marcos , Cascalho João Pedro , Tuaty-Guerra Miriam , Gaudêncio Maria José , Gonçalves Jorge , Relvas Paulo , Garel Erwan , Júnior Luciano , Henriques Victor , Terrinha Pedro , Arteaga Jorge , Ramos Ana
Published: March 2020

Artificial nourishment of sandy beaches using sediment from borrow areas located on the continental shelf is increasingly a recommended solution for reversing the erosion process that affects the coastal zone. However, the impact of sand extraction in the shelf and deposition on the beach on the benthic communities (structure and functioning) is still poorly known, contributing to the lack of information needed for the assessment of Descriptor 6 (Sea-floor integrity) of the Marine Strategy Framework Directive (MSFD).

The aim of this work is to evaluate the morphological and ecosystem impacts of sand extraction at the inner shelf, as well as the consequent impacts of sand deposition at the nourished beaches. In this context, short-term and long-term monitoring activities based on a multidisciplinary approach were implemented at new and former borrow areas located in the southern Portugal (Algarve) inner continental shelf and adjacent beaches. These activities include multibeam bathymetric surveys complemented by surface sediment sampling, wave and current measurements, and a fluorescent tracer-marked sand experiment. Moreover, benthic macrofauna composition and structure are being studied at borrow areas (former and new) and at the nourished beaches. The acquired data allow a first assessment of the recovery rates regarding the sea-bottom morphology and benthic communities, and contribute to a better understanding of the involved processes.

The authors would like to acknowledge the financial support FCT through project UIDB/50019/2020 – IDL and ECOEXA project (MAR-01.04.02-FEAMP-0016)
High-end solution techniques and accurate reference solutions: towards a community-wide benchmarking effort for stochastic inverse modeling of groundwater flow
Authors: Nowak Wolfgang , Xu Teng , Reuschen Sebastian , Hendricks Franssen Harrie-Jan , Guadagnini Alberto
Published: March 2020

Geostatistical inversion modeling methods aim at characterizing spatial distributions of (typically hydraulic) heterogeneous properties from indirect information (e.g., piezometric heads, concentrations), while quantifying their uncertainties. Many methods have been developed, but only a few large intercomparison studies have been performed in the past decades. We present a benchmarking initiative for geostatistical inversion with the goal to enable a truly objective and accurate intercomparison and testing of new and existing methods.

This initiative defines an agreed-upon set of benchmarking scenarios. The benchmarking set focuses on addressing fully-saturated groundwater flow in multi-Gaussian log-hydraulic conductivity fields. Our study provides reference solutions and illustrates the high-end algorithms we advance and develop to compute these solutions on massive high-performance computing equipment. We rely on Monte-Carlo Markov-Chain algorithms with a modified Metropolis-Hastings sampler, following the idea of preconditioned Crank-Nicholson MCMC (pCN-MCMC). In this technique, the acceptance probability of MCMC only depends on likelihood ratios, while being independent from the geostatistical prior. This largely improves acceptance rates and so reduces computational costs.

To further improve the accuracy and efficiency for Bayesian inversion of multi-Gaussian log-hydraulic conductivity fields, we combine pCN-MCMC with parallel tempering. Parallel tempering can handle the challenges associated with the need to explore large parameter spaces with possibly multi-modal distributions: it improves the efficiency of exploring the target posterior by exchange swaps between cold chains and hot chains that run in parallel, where the hot chains mainly explore the parameter space and colder chains exploit the identified high-likelihood regions.

Our new algorithm, hereafter termed pCN-PT, is tested against (a) accurate analytical solutions (kriging) in a high-dimensional, linear setting; (b) rejection sampling in a high-dimensional, non-linear problem with only few measurements; and (c) pCN-MCMC in multiple independent runs in a high dimensional, non-linear scenario with sufficient measurements. These tests are also performed in the established benchmarking scenarios. We invite all interested researchers to test and compare different inverse modeling method(s) in these benchmarking scenarios.
No N2 fixation in the Bay of Bengal?
Authors: Löscher Carolin , Mohr Wiebke , Bange Hermann , Canfield Donald
Published: March 2020

The Bay of Bengal (BoB) has long stood as a biogeochemical enigma with subsurface waters containing extremely low, but persistent, concentrations of oxygen (O2) in the nanomolar range which - for some, yet unconstrained reason- are prevented from becoming anoxic. One reason for this may be
the low productivity of the BoB waters due to nutrient limitation, and the resulting lack of respiration of organic material at intermediate waters. Thus, the parameters determining primary production are key to understanding what prevents the BoB from developing anoxia. Primary productivity in the sunlit surface layers of tropical oceans is mostly limited by the supply of reactive nitrogen through upwelling, riverine flux, atmospheric deposition, and biological dinitrogen (N2) fixation. In the BoB, a stable stratification limits nutrient supply via upwelling in the open waters, and riverine or atmospheric fluxes have been shown to support only less than one quarter of the nitrogen for primary production. This leaves a large uncertainty for most of the BoB’s nitrogen input, suggesting a potential role of N2 fixation in those waters.
Here, we present a survey of N2 fixation and carbon fixation in the BoB during the winter monsoon season. We detected a community of N2 fixers comparable to other OMZ regions, with only a few cyanobacterial clades and a broad diversity of non-phototrophic N2 fixers present throughout the water column (samples collected between 10 m and 560 m water depth). While similar communities of N2 fixers were shown to actively fix N2 in other OMZs, N2 fixation rates were below the detection limit in our samples covering the water column between the deep chlorophyll maximum and the OMZ.
Consistent with this, no N2 fixation signal was visible in δ15N signatures. We suggest that the absence of N2 fixation may be a consequence of a micronutrient limitation or of an O2 sensitivity of the OMZ diazotrophs in the BoB. To explore how the onset of N2 fixation by cyanobacteria compared to nonphototrophic N2 fixers would impact on OMZ O2 concentrations, a simple model exercise was carried out. We observed that both, photic zone-based and OMZ-based N2 fixation are very sensitive to even minimal changes in water column stratification, with stronger mixing increasing organic matter production and export, which would exhaust remaining O2 traces in the BoB.       
Broadening access to supercomputers for CMIP6 and CORDEX multimodel comparisons
Authors: Kindermann Stephan , Moreno Maria
Published: March 2020

We will present a new service designed to assist the users of model data in running their analyses in world-class supercomputers. The increase of data volumes and model complexities can be challenging for data users with limited access to high performance computers or low network bandwidth. To avoid heavy data transfers, strong memory requirements, and slow sequential processing, the data science community is rapidly moving from classical client-side to new server-side frameworks. Three simple steps enable server-side users to compute in parallel and near the data: (1) discover the data you are interested in, (2) perform your analyses and visualizations in the supercomputer, and (3) download the outcome. A server-side service is especially beneficial for exploiting the high-volume data collections produced in the framework of internationally coordinated model intercomparison projects like CMIP5/6 and CORDEX and disseminated via the  Earth System Grid Federation (ESGF) infrastructure. To facilitate the adoption of server-side capabilities by the ESGF users, the infrastructure project of the European Network for Earth System Modelling (IS-ENES3) is now opening its high performance resources and data pools at the CMCC (Italy), JASMIN (UK), IPSL (France), and DKRZ (Germany) supercomputing centers. The data pools allow access to results from several models on the same site and the data and resources are locally maintained by the hosts. Besides, our server-side framework not only speeds the workload but also reduces the errors in file format conversions and standardizations and software dependencies and upgrade. The service is founded by the EU Commission and it is free of charge. Find more information here: https://portal.enes.org/data/data-metadata-service/analysis-platforms. Demos and tutorials have been created by a dedicated user support team. We will present several use cases showing how easy and flexible it is to use our analysis platforms for multimodel comparisons of CMIP5/6 and CORDEX data. 
The Impact of Taiwan’s Rugged Orography on Air Pollutant Transport and the Numerical Modeling of 20 March 2018 Case
Authors: Wang Pao K. , Lin Chuan-Yao
Published: March 2020

Taiwan is a subtropical island with an area of only about 36,000 km2 and yet packed with high density of mountains. There are 268 peaks that are taller than 3000 m in elevation and, as a result, the mountains are extremely rugged. Such rugged orography will certainly have great influence on the local circulation and consequently impact on the transport of air pollutants. It is thus necessary to understand the impact of the orography on air flow before we can interpret the measured data during the EMeRGe-Asia campaign in March-April 2018 correctly.

For the above purpose, we performed high resolution numerical simulations of the flow around Taiwan region for two cases using the Weather Research and Forecast (WRF) model. The first one is a highly stagnant case where Taiwan was under the influence of a high pressure system occurring on 10 November 2018. Two horizontal resolutions are used: 1 km and 2 km, both show very similar flow and cloud patterns as revealed by satellite images of the day. Detailed analysis of the simulated results including the flow pattern and isentropic analysis will be shown to illustrate that low level pollutants can be transported upward to at least 1 km altitude even under such calm weather.

The second one is the 20 March 2018 case which occurred during the EMeRGe-Asia campaign. Unlike the above stagnant case, this was a more turbulent situation when a typhoon was approaching from the east and a southerly flow carried air pollutants from SE Asia. The 1 km resolution simulation shows good match with satellite observation. The simulation results show a substantial concentration of VOC at ~ 3000 m altitude near Taiwan whereas the VOC was very low near the surface. The model reproduces this feature well and hence it appears that the model’s predictions are credible. More detailed analyses are being performed and comparison of the results with combined ground and aircraft observations to illustrate the impact of the orography on the transport of pollutants.  
The impact of ensemble meteorology on volcano emission estimates and ash dispersion forecasts
Authors: Harvey Natalie , Dacre Helen , Webster Helen
Published: March 2020

In the event of a volcanic eruption airlines need to make fast decisions about which routes are safe to operate and to ensure airborne aircraft land safely.  Currently these high-impact decisions are based on qualitative forecasts produced without any indication of uncertainty. Two of the largest sources of uncertainty in forecasting ash cloud location and concentration are the emissions of ash from the volcano and the meteorological situation. This study extends the UK Met Office Inversion Technique for Emission Modelling (InTEM) system to use an ensemble of meteorological conditions to investigate the dependence of emission estimates on wind field and wet deposition uncertainty. In the case of the 2011 Grimsvotn eruption, preliminary work shows that the impact of the variability of the ensemble wind fields is greater than that of the variability in the wet deposition. The next steps in this research are to quantify the improvement in the forecasts of ash location due to this ensemble approach and to develop an operational methodology that can be applied in a real-time emergency response situation.
Promising subseasonal forecasting results based on machine learning
Authors: Kämäräinen Matti
Published: March 2020

A purely statistical machine learning (ML) approach was applied to forecast near-surface temperature and precipitation anomalies over land areas in the Northern Hemisphere and Tropics. A high number of principal components (PCs) from the key variables, most importantly sea surface temperatures and the near-tropopause geopotential from reanalyses, was used as predictors to forecast the 2-weekly mean predictand anomalies in each location. Separate models were fitted for different seasons and lead times in the range of 1–6 weeks.

To select and weight the predictors and to reduce the risk of overfitting, such ML methods as least absolute shrinkage and selection operator (LASSO) regularization and ensembling based on random sampling of the predictor data were used in addition to the dimensionality reduction with PCs.

Skill analysis of the independent test sample results show that both the climatological and persistence reference forecasts were inferior compared to the ML approach on average, with all lead times, and in the majority of the target grid cells. Also, the ML approach achieved a skill that was generally comparable to the European Centre for Medium-Range Weather Forecasts (ECMWF) dynamical model.

 

Previously, these particular ML methods have been shown to work in a regional approach in Europe for seasonal time scales. According to the new results, they also work in the near-global domain and in the challenging subseasonal time scales.
A large-scale detachment system in the central Eastern Alps (Upper Austroalpine Unit, Austria)
Authors: Werdenich Manuel , Iglseder Christoph , Grasemann Bernhard , Rantitsch Gerd , Huet Benjamin
Published: March 2020

Based on new structural field data and Raman micro-spectroscopy on carbonaceous material a major detachment juxtaposing Drauzug-Gurktal Nappe System (DGN) against the transgressive Permo-Mesozoic cover sequence of the Ötztal-Bundschuh Nappe System (BN, Stangalm Mesozoic s. str.) in the area SE of Flattnitz (Carinthia, Austria). An Eo-alpine top-SE kinematic has been identified.

The hanging wall unit comprise lithologies of the DGN phyllites, conglomerates and graphite schists (Stolzalpe nappe), which have experienced only low grade greenschist deformation. Raman constrains 350°C±40°C.

The footwall unit consists of dolomitic ultra-mylonites, calcitic marble mylonites, meta-conglomerates and quarzites (Stangalm Mesozoic and Kuster nappe), which have experienced at least four main deformation phases. The oldest structures (D1) corresponding to Eo-Alpine nappe stacking are overprinted by (D2) isoclinal recumbent folds with E-W oriented shallow dipping fold axis and an axial plane schistosity, dipping shallowly to WSW. Ductile to brittle-ductile top to the E shearing (D3) is indicated by ESE-trending stretching lineation, C-type shear bands, stylolites, crystal- and shape preferred orientations of mineral grains. Late brittle deformation (D4) is recorded in steep joint sets with dip-directions to NW. Raman constrains 480°C±40°C.

The detachment zone comprises a complicate zone of high strain including units from DGN folded together within the Stangalm Mesozoic, which have experienced the same deformation as the BN.
Detecting and Identifying Floating Plastic Debris in Coastal Waters using Sentinel-2 Earth Observation Data
Authors: Biermann Lauren , Clewley Daniel , Martinez-Vicente Victor , Topouzelis Konstantinos
Published: March 2020

Satellite remote sensing is an invaluable tool for observing our earth systems. However, few studies have succeeded in applying this for detection of floating litter in the marine environment. We demonstrate that plastic debris aggregated on the ocean surface is detectable in optical data acquired by the European Space Agency (ESA) Sentinel-2 satellites. Furthermore, using an automated classification approach, we show that floating macroplastics are distinguishable from seawater, seaweed, sea foam, pumice, and driftwood.

Sentinel-2 was used to detect floating aggregations likely to include macroplastics across four study sites, namely: coastal waters of Accra (Ghana), Da Nang (Vietnam), the east coast of Scotland (UK), and the San Juan Islands (BC, Canada). Aggregations were detectable on sub-pixel scales using a Floating Debris Index (FDI), and were composed of a mix of materials including sea foam and seaweed. A probabilistic machine learning approach was then applied to assess if detected plastics could be discriminated from the natural sources of marine debris. Our automated Naïve Bayes classifier was trained using a library of pumice, seaweed, timber, sea foam and seawater detections, as well as validated macroplastics from Durban Harbour (South Africa). Across the four study sites, suspected marine plastics were classified as such with an accuracy approaching 90%. The ‘misclassified’ plastics were mostly identified as seawater, suggesting an insufficient amount of pixel was filled with materials.

Results from this study show that plastic debris aggregated on the ocean surface can be detected in optical data collected by Sentinel-2, and identified. With the aim of generating global ‘hotspot’ maps of floating plastics in coastal waters, automating this two-stage process across the Sentinel-2 archive is being progressed; however, the method would also be applicable to drones and other remote sensing platforms with similar band characteristics. To extend remote detection methods to river systems and optically complex and/or tidal coastal waters, in situ data collection across optical water types is the next key step.
Concept for shallow geothermal opportunity mapping
Authors: Boon David , Farr Gareth , Williams Laura , Thorpe Stephen , Patton Ashley , Kendall Rhian , Holden Alan , Scheidegger Johanna , Self Suzanne , Abesser Corinna , Harcombe Gareth
Published: March 2020

Reaching Net Zero CO2 emissions by 2050 will require rapid and wide-scale deployment of renewable heating technologies in rural and urban areas, including open and closed loop type production wells and borehole heat exchangers, supplying individual, shared, and centralised heat pumps as part of wider district heating and cooling grids.  Ground and groundwater conditions are naturally variable and are a key factor in system viability, capital cost and long-term performance.  Engineering approaches for heating and cooling of buildings should be optimised for the local thermo-geological conditions to avoid system interference and thermal degradation.  Sustainable use of shallow geothermal systems can be achieved by adopting an environmental stewardship approach, integrating geological information within energy master plans, taking full advantage of subsurface data visualisation technology and integrated planning and modelling tools.

We present a method for creating a digital shallow geothermal opportunities map - mostly aimed at moderate- to expert-skill level geoenvironmetal and energy consultants, planners and civil engineers.  The output is a digital 1:50 000 scale equivalent thematic map, that provides a synthesis of available technical information by combining data such as 3D superficial geological model data - delimiting aquifer and non-aquifer boundaries, groundwater levels and temperatures, aquifer thickness, flow direction, possibly with inset tables summarising groundwater chemistry and key physical properties of the main geological units such typical thermal conductivity.  Built infrastructure that could constrain drilling locations, as well as potential water discharge points and open water heat source and storage opportunities, such as sewers, rivers, canals, docks, and lakes, might also be included in the map.  Local development plans and heat demand mapping data could then be integrated with the opportunities map to identify and prioritise districts that would benefit from more detailed viability studies for conversion of fossil fuel heating systems to low carbon heating and cooling technologies.

This project has received funding from the European Union’s H2020 research and innovation programme under the GeoERA MUSE project – Managing Urban Shallow Geothermal Energy.