bluuebunny/crossref_metadata_2025 huggingface dataset:
Etesian winds after major volcanic eruptions
Authors: Misios Stergios , Logothetis Ioannis , Knudsen Mads F. , Karoff Christoffer , Tourpali Kleareti
Published: March 2020

Etesians winds are northerly winds in the lower atmosphere, blowing over the Aegean basin from early summer to early autumn, regulating summer time heating levels. The interannual variability of Etesians is thought to be linked to the extended Indian Summer Monsoon and tropical Pacific Region. Here, we are investigating the response of Etesians to major volcanic eruptions with the aid of ensembles of historical simulations. Specifically, we are making use of the CESM Last Millennium and Large Ensemble simulations to investigate modelled Etesian changes in the post-eruption one to three years. We find consistent changes for all major eruptions over the last millennium of reduced amplitude peaking in the first year after the eruption. Interestingly, the Laki eruption shows a similar signal to the other major tropical Eruptions. Modelled results are compared to signals in the observational record and a possible mechanism connecting Etesians to the Indian Monsoon region is discussed.
3D numerical studies on stratification and mixing processes affecting fine sediment transport in the pre-dam of the Dhünn reservoir in Germany
Authors: Gonzalez Wendy , Klassen Irina , Jakobs Anne , Seidel Frank
Published: March 2020

Fine sediment transport processes and the thermodynamics in reservoirs are key processes governing the water quality of reservoirs. With regard to a sustainable sediment management of reservoirs, the prediction of sediment transport and deposition is becoming increasingly important.

The subject of the present work was the 3D numerical simulation of fine sediment transport in a reservoir taking into account stratification and mixing effects which in turn are caused by temperature gradients and wind effects. In order to understand and investigate the driving factors for stratification processes and their impact on fine sediment distribution, the great pre-dam of the Dhünn reservoir in Germany served as case study. The investigations were conducted in sensitivity analyses adopting a 3D sediment transport model with Delft 3D. The impact of various physical and numerical parameters on temperature and fine sediment transport modeling was examined: the number of vertical layers, the input data for the heat model (e.g. relative humidity, air temperature, cloud coverage, solar radiation), the vertical diffusivity and wind effects. The sensitivity studies showed that the input data for the heat model have a minor impact on the temperature and sediment transport modeling within the tested range of parameters. However, the vertical diffusivity and especially the inclusion of wind showed a greater influence on the simulated temperature and suspended sediment concentration gradients. The temperature modeling results by inclusion/exclusion of wind were qualitatively compared with temperature data from literature and with measurement data over a period of one month. Hereby, the simulations showed a good agreement with measurement data by exclusion of wind effects.

The results of the studies provide a solid basis for the development of further models in fields where fine sediment transport is affected by stratification processes and can also be very useful in terms of a better understanding of the interactions between temperature, wind and fine sediment transport.
The influence of light on soil community structure and consequences for soil CO2, CO18O and COS exchange
Authors: Wingate Lisa , Foucault Clement , Fanin Nicolas , Sauze Joana , Maron Pierre-Alain , Nowak Virginie , Terrat Sebastian , Mondy Samuel , van Schaik Evert , Crouzet Olivier , Ogée Jérôme , Wohl Steven
Published: March 2020

The stable oxygen isotope composition of atmospheric CO2 and the mixing ratio of carbonyl sulphide (COS) are potential tracers of biospheric CO2 fluxes at large scales. However, the use of these tracers hinges on our ability to understand and better predict the activity of the enzyme carbonic anhydrase (CA) in different soil microbial groups, including phototrophs. Because different classes of the CA family (α, β and γ) may have different affinities to CO2 and COS and their expression should also vary between different microbial groups, differences in the community structure could impact the ‘community-integrated’ CA activity differently for CO2 and COS. Four soils of different pH were incubated in the dark or with a diurnal cycle for forty days to vary the abundance of native phototrophs. Fluxes of CO2, CO18O and COS were measured to estimate CA activity alongside the abundance of bacteria, fungi and phototroph genes. The abundance of soil phototrophs increased most at higher soil pH. In the light, the strength of the soil CO2 sink and the CA-driven CO2-H2O isotopic exchange rates correlated with phototroph abundance. COS uptake rates were attributed to fungi whose abundance was positively enhanced in alkaline soils but only in the presence of increased phototrophs. In addition we developed a metabarcoding approach to reveal the interactions of specific taxonomic groups incuding photosynthetic eukaryotic algae and cyanobacteria when exposed to light and their impact on flux rates. Our findings demonstrate that soil-atmosphere CO2, COS and CO18O fluxes are strongly regulated by the microbial community structure in response to changes in soil pH and light availability and support the idea that different members of the microbial community express different classes of CA, with different affinities to CO2 and COS.
Sensitivity of middle atmosphere GW forcing to vertical model resolution
Authors: Schneidereit Andrea , Schmidt Hauke , Stephan Claudia
Published: March 2020

Several current general atmospheric circulation models provide sufficiently high resolutions to resolve important parts of the internal gravity wave spectrum allowing for numerical experiments without GW drag parameterizations. GWs start to be well resolved from horizontal wavelengths of about 7 times the horizontal grid spacing. How much does the resolved wave spectrum and its forcing on the mean circulation depend on the vertical resolution?

−1,The middle atmosphere summer hemisphere provides a suitable background to investigate this question. The mean stratospheric and mesospheric circulation is characterised by prevailing easterlies which prevent planetary wave propagation upwards and represents a mean state driven by IGWs. The sensitivity of the forcing by IGWs is analysed on the basis of the Eliassen-Palm (EP) flux divergence, which describes the forcing on the circulation by resolved eddies.
Model simulations are performed using the upper atmosphere version of the ICON (ICOsahedral Nonhydrostatic) general circulation model, UA-ICON (Borchert et al. 2019, GMD). The simulations start in October and run for an extended austral summer season until March with a horizontal grid spacing of roughly 20 km. The top of the model atmosphere is located at 150 km. Three different model configurations are used with 90, 180, and 360 vertical model layers. The mean vertical grid spacing ranges from roughly 1300 m (90 layers) to 320 m (360 layers) at stratospheric levels, and from roughly 2300 m to 500 m at mesospheric levels. Gravity wave drag parameterizations (orographic and non-orographic) are turned off. The resolved forcing on the mean state due to the EP flux divergence is decomposed into contributions of different scales with respect to horizontal wave numbers. For contributions of IGWs wave numbers above 20 are considered.

The stratospheric and mesospheric easterlies appear stronger in the lower resolution from October to the end of the austral summer season. Westerlies occur above the mesopause. This strong vertical gradient in the zonal mean zonal wind amplifies in the lower resolution. At the beginning of the simulation period, differences between the mean states are weak, of the order of 5 ms−1 , and strengthen during the summer season. The forcing due to internal GWs appears stronger in the lower resolution at higher altitudes and amplifies in the region of the strong vertical gradient of the zonal mean zonal wind. Furthermore, wave spectra are discussed. In accordance with previous studies, an increased vertical resolution results in a reduction of the IGW forcing close to strong zonal mean zonal wind gradients in the upper mesosphere/lower thermosphere.
Climate change impacts on biomes and aridity in Peru
Authors: Zevallos Ruiz Jose Augusto , Huerta Adrian , Lavado Waldo , Sabino Evelin , vega Fiorella , Felipe Oscar
Published: March 2020

In recent years, there has been an increasing interest in estimate future conditions on biomes and aridity due to climate change. Using a new observed-based gridded dataset and remote sensing products, we evaluate the future features in terms of potential biomes (PB) and aridity index (AI) over Peru. 

Ten PBs were established for the present conditions by grouping the ecosystems maps at the national scale. The map presents biomes within areas from 1.08 to 42.44% of total coverage. In order to handle imbalanced data, we designed a calibration and validation scheme for three machine learning algorithms (Random Forest, SVM, and KNN) as follow: first, we perform a gridded search for the best parameters of each model; second, we tested the robustness of each model with a cross validations, checking their f1 score, the confusion matrix and the weighted average precision-recall; finally, we performed a cost-sensitive learning to make more suitable the learning approach for very imbalanced data. The best model is going to be used to predict future conditions of PB. For AI, we evaluate the present trend and quantified the contributions of climate variables to Ai variations. Also, the relationship between AI and vegetative greening was explored. The future change of AI is seen by its spatial variation (migration) of the dryland subtypes.

The preliminary results showed that random forest worked best for the PB imbalanced data, having a 0.84 weighted average in precision and recall metric. The model reproduces 9 of the PB with low error 4.5% and overestimates 34.52 % one of them in the Amazon. Furthermore, there is an increasing slight trend (not significant) of AI at the drainage-scale, mainly in the Pacific. We hypothesize that there is a migration of dryland subtypes from dry to wet areas in the present time. 

This research is part of the project “Apoyo a la Gestión del Cambio Climatico 2da. Fase” financed by The Swiss Agency for Development and Cooperation (SDC).
Seismicity of Mars
Authors: Giardini Domenico , Lognonne Philippe , Banerdt Bruce , Boese Maren , Ceylan Savas , Clinton John , van Driel Martin , Garcia Raphael , Kawamura Taichi , Khan Amir , Knapmeyer Martin , Panning Mark , Perrin Clement , Pike Tom , Stähler Simon
Published: March 2020

NASA’s InSight mission deployed the Seismic Experiment for Interior Structure (SEIS) instrument on Mars, with the goal of detecting, discriminating, characterizing and locating the seismicity of Mars and study its internal structure, composition and dynamics. 44 years since the first attempt by the Viking missions, SEIS has revealed that Mars is seismically active. So far, the Marsquake Service (MQS) has identified 365 events that cannot be explained by local atmospheric or lander-induced vibrations, and are interpreted as marsquakes. We identify two families of marsquakes: (i) 35 events of magnitude MW=3-4, dominantly long period in nature, located below the crust and with waves traveling inside the mantle, and (ii) 330 high-frequency events of smaller magnitude and of closer distance, with waves trapped in the crust, exciting an ambient resonance at 2.4Hz. Two long period events with larger SNR and excellent P and S waves occurred on Sol 173 and 235, visible both on the VBB and the SP channels; the location of these events has been determined at distances of 26°-30° towards the East, close to the Cerberus Fossae tectonic system. Over ten additional long period events show consistent body-wave phases interpreted as P and S phases and can be aligned with distance using models of P and S propagation. Marsquakes have spectral characteristics similar to seismicity observed on the Earth and Moon. From the spectral characteristics of the recorded seismicity and the event distance, we constrain attenuation in the crust and mantle, and find indications of a potential low S-wave-velocity layer in the upper mantle. In contrast, the high-frequency events provide important constraints on the elastic and anelastic properties of the crust. The first seismic observations on Mars deliver key new knowledge on the internal structure, composition and dynamics of the red planet, opening a new era for planetary seismology. Here we review the seismicity detected so far on Mars, including location, distance, magnitude, magnitude-frequency distribution, tectonic context and possible seismic sources.
Numerical modeling of the natural and anthropogenic factors influence on the past and future changes in polar, mid-latitude and tropical ozone
Authors: Smyshlyaev Sergei , Blakitnaya Polina , Motsakov Maxim , Galin Vener
Published: March 2020

The INM RAS – RSHU chemistry-climate model of the lower and middle atmosphere is used to compare the role of natural and anthropogenic factors in the observed and expected variability of stratospheric ozone. Numerical experiments have been carried out on several scenarios of separate and combined effects of solar activity, stratospheric aerosol, sea surface temperature, greenhouse gases, and ozone-depleting substances emissions on ozone for the period from 1979 to 2050. Simulations for the past and present periods are compared to the results of ground-based and satellite observations, as well as MERRA and ERA-Interim re-analysis. Estimation of future ozone changes are based on different scenarios of changes in solar activity and emissions of ozone-depleting substances and greenhouse gases, as well as the possibility of large volcanic aerosol emissions at different periods of time.
Drought stress affects carbon partitioning between plant primary and secondary metabolism in Scots pine trees
Authors: Kreuzwieser Jürgen , Grün Michel , Eiblmeier Monika , Bamberger Ines , Yanez-Serrano Ana Maria , Fasbender Lukas , Werner Christiane
Published: March 2020

The interplay of the processes controlling carbon partitioning into plant primary and secondary metabolisms, such as respiratory CO2 release and Volatile Organic Compound (VOC) biosynthesis, is still not fully understood. Pyruvate is a key metabolite which is formed in primary metabolism and acting as substrate in numerous secondary pathways forming many BVOCs, such as isoprene, volatile terpenoids, oxygenated compounds (acetaldehyde, acetic acid), benzenoids and fatty acid oxidation products (several wound VOCs), which can be emitted by plants. Within the ERC project VOCO, we established an innovative analytical setup enabling us to simultaneously measure stable carbon isotope composition of leaf exchanged CO2 (Infrared Isotope spectroscopy IRIS) together with VOC release (PTR-TOF-MS and GC-MS-C-IRMS). Position specific 13C-labeled pyruvate and 13CO2 were applied in tracer experiments to elucidate carbon partitioning at metabolic branching points into VOCs vs. CO2 in drought stressed Scots pine trees.

We observed treatment specific patterns of VOC emission including volatile terpenoids, oxygenated BVOCs and green leaf volatiles. Tracing 13C, we elucidated if compounds were de novo synthesized from 13C-labeled pyruvate or 13CO2. Position-specific labeling with [1-13C]-pyruvate and [2-13C]-pyruvate suggested that most VOCs were synthesized from the C2-C3 moiety of pyruvate whereas the C1 position was decarboxylated resulting in 13CO2 release by dark respiration in the light. We observed drought stress related shifts in 13CO2 release and VOC emissions. Our observations suggest that VOC emissions are associated with significant pyruvate C1 decarboxylation which is released to the atmosphere. This novel approach contributes to a better understanding of the metabolic links of processes of primary and secondary plant metabolisms which is relevant for the vegetation-atmosphere exchange of CO2 and VOCs. 
Hybrid energy module for experiments and studies in remote locations
Authors: Krassovski Misha , Riggs Jeffery , Tavino Chris , Wullschleger Stan , Heinz Susan
Published: March 2020

Increased concerns about regional and global climate change in recent decades has led to a significant expansion of monitoring, observational, and experimental sites in remote areas of the world. During this same time, advances in technology and availability of low-power equipment, have allowed increasingly sophisticated measurements with an increasingly wide variety of instruments, sensors, and sensor networks. However, the deployment and use of these technologies in remote locations is restricted not only by harsh environmental conditions, but by the availability of electrical power and communication options. With this presentation we would like to share our experience of designing and building hybrid energy (solar and wind) module that can be used to provide power and communication capabilities for remote installations.
The effects of afforestation on Fe mobilization in soils and potential for leaking into surface waters
Authors: Škerlep Martin , Johansson Ulf , Berggren Kleja Dan , Persson Per , Kritzberg Emma S
Published: March 2020

Increasing surface water concentrations of Fe and DOC (browning), have been reported around the northern hemisphere in the last couple of decades. This increase has far-reaching ecological and societal implications, as it alters the light climate in water and decreases the quality of drinking water. One of the hypothesis behind the increase has been that afforestation and a dominance of coniferous forest have increased the availability of Fe and DOC for transport from soils into surface waters. The accumulation of organic soil layers in coniferous forests increases acidity and the amounts of organic acids in soils and may thus enhance weathering, solubility and mobilization of Fe as the forest ages. In this study we examined the effects of afforestation and growth of Norway spruce on the mobilization and potential leakage of Fe and DOC from soils to surface waters. To represent the effects of ageing forest we used plots with spruce stands of different ages (35, 61, 90 years) and unforested control plots in their immediate proximity, in Tönnersjöheden experimental forest (Sweden). Soil water collected in lysimeters (installed below the organic horizon and in the mineral soil) and analyzed for Fe, Fe speciation, using X-ray absorption spectroscopy (XAS), as well as DOC, metals, major anions and cations. Soil samples were analyzed for Fe speciation and crystallinity at different depths. Results from the soil water analysis show that more Fe was mobile in older spruce forest stands with higher DOC concentrations and lower pH. Covariation of Fe and DOC concentrations in soil waters, indicate the dependence of Fe on DOC to solubilize and stay in solution. Preliminary results from our XAS analysis also indelicate a considerable amount of Fe(II) in soil water that is likely stabilized from oxidation by organic complexation. Surprisingly Fe extracted from the organic (O) soil horizon showed the highest crystallinity and crystallinity did not vary much between soils of different stand ages.  The results of this study indicate that afforestation promotes Fe and DOC availability for export into surface waters as well as strengthens the notion that the effects of afforestation are not immediate, but take time as soils develop slowly. As afforestation and dominance of coniferous forest continues in many parts of the northern hemisphere, we can expect further increase of Fe and DOC in surface waters.
Landscape fires and public health
Authors: Johnston Fay
Published: March 2020

Landscape fires interact with human health in a diversity of ways, both positive and negative, and can influence many basic human needs including promoting or threatening food supplies, protecting or damaging homes and environments, and influencing water and air quality. Public health impacts are thus shaped by the context and scale of landscape fires and the direct and indirect pathways for their impacts on people. This presentation will discuss a range of scenarios, from planned burning to severe wildfire disasters, to illustrate the main ways in which landscape fires influence both the physical and mental health of people and societies.
Investigating Thunderstorm HF/VHF Radio Bursts with Weak Lower Frequency Radiation
Authors: Liu Ningyu , Dwyer Joseph
Published: March 2020

While the spectrum of lightning electromagnetic radiation is known to peak around 5-10 kHz in the very low frequency (VLF) range, intense high frequency/very high frequency (HF/VHF) radiation can be produced by various lightning related processes. In fact, thunderstorm narrow bipolar events (NBEs), which are capable of initiating lightning, are the most powerful HF/VHF sources in nature on Earth. But even for NBEs, the spectral intensity in HF/VHF is still many orders of magnitude weaker than that of lower frequencies (Liu et al., JGR, 124, https://doi.org/10.1029/2019JD030439, 2019). HF/VHF bursts with weak VLF signals, however, can also be produced by thunderstorms. These bursts may be related to the thunderstorm precursor events noted by Rison et al. (Nat. Commun., 7, 10721, 2016) and are also found to precede a large fraction of lightning initiation (Lyu et al., JGR, 124, 2994, 2019). They are also known as continual radio frequency (CRF) radiation associated with volcanic lightning (Behnke et. al., JGR, 123, 4157, 2018).

 

In this talk, we report a theoretical and modeling study to investigate a physical mechanism for production of those HF/VHF bursts. The study is built on the theory developed recently concerning the radio emissions from an ensemble of streamers (Liu et al., 2019). We find an ensemble of streamer discharges that develop in random directions can produce HF/VHF radiation with intensity comparable to those all developing in a single direction, but the VLF intensity is many orders of magnitude weaker. The results of our study support the conclusions of Behnke et. al (2018) that CRF is produced in the absence of large-scale electric field, it results in insignificant charge transfer, and it is caused by streamers. In the context of the HF/VHF bursts preceding lightning initiation (Lyu et. al, 2019), our results imply that highly localized strong field regions exist in thunderstorms and streamers take place in those regions, which somehow precondition the medium for lightning initiation.
Advanced fusion of geophysical data through combined use of 2D Discrete Wavelet Transform and Multiresolution Singular Value Decomposition applied to GPR-3D and magnetic data
Authors: Oliveira Rui Jorge , Caldeira Bento , Teixidó Teresa , Borges José Fernando
Published: March 2020

Despite strong evidences that are visible at the surface that suggests the presence of buried structures, sometimes, both the GPR and magnetic data do not allow to clearly about the presence of these structures. Usually, this lack of perceptibility is due to the physical and chemical conditions of the medium that produces an increasing of background noise and masks the useful information. This causes a decrease in the signal-to-noise ratio of the data, preventing a good assessment about the existence of buried structures at subsurface.

Nevertheless, we believe that the recorded signal of both methods has the useful part of the signal hidden. Data fusion techniques are widely used in brain tumour detection in medicine by combining data from different clinical exams, both with low perceptibility.

This work presents an approach that allows using advanced fusion algorithms to combine geophysical data from GPR-3D and magnetics. This creates an enhanced image from both datasets with better quality than the individual images from each method.

The data fusion approach is performed through the combined use of 2D Discrete Wavelet Transform, Multiresolution Singular Value Decomposition and Image Gradient. This scheme allows us to select the useful information to obtain a higher quality and sharper fused image using the best of input datasets. The geophysical data fusion was successfully tested on three datasets, with different levels of perceptibility: high, intermediate and low.

 

Acknowledgment: This work is co-funded by the ICT Project (UID/GEO/04683/2019) with the reference POCI-01-0145-FEDER-007690, by the Project SFRH/BSAB/143063/2018 (FCT) and by the INTERREG 2014-2020 Program, through the "Innovación abierta e inteligente en la EUROACE" Project, with the reference 0049_INNOACE_4_E.
Observing the signature of the magnetic field's behaviour in the radial variation of inner core anisotropy
Authors: de Jong Janneke , de Groot Lennart , Deuss Arwen
Published: March 2020

The release of latent heat and lighter materials during inner core solidification is the driving force of the liquid iron flow in the outer core which generates the Earth's magnetic field. It is well known that the behaviour of the magnetic field varies over long time scales. Two clearly identifiable regimes are recognized, (i) superchrons and (ii) periods of hyperactivity (Biggin et al. 2012). Superchrons are characterized by an exceptionally low reversal rate of the magnetic pole and are associated with a low core mantle boundary (CMB) heat flux. Hyperactive periods are defined by a high reversal rate and have a high CMB heat flux.

Here we investigate whether the occurrence of these two regimes is related to radial variations in inner core seismic structure. Using seismic body-wave observations of compressional PKIKP-waves (Irving & Deuss 2011, Waszek & Deuss 2011, Lythgoe et al. 2013)., we construct a model of inner core anisotropy by comparing the difference between travel times for polar and equatorial rays. Anisotropy is the directional dependence of wave velocity and is determined by the structure of iron crystals in the inner core, hence changes in seismic anisotropy are due to changes in inner core crystal texture. We invert for radial changes in anisotropy while allowing for lateral variations and find that a model of the inner core containing five layers best fits our data. The model contains an isotropic uppermost inner core and four deeper layers with varying degrees of anisotropy.

Texture differences of the inner core iron crystals have been linked to changes in the solidification process of the inner core (Bergman et al. 2005), i.e. the motor of outer core flow. Therefore, the observed anisotropy variation, caused by variations of inner core solidification, might be related to changes in the behaviour of the magnetic field. Using an inner core growth model (Buffett et al. 1996) we convert depth to time for a range of inner core nucleation ages between 3.0 and 0.5 Ga (Olsen 2016). We find a remarkable correlation between the solidification time of the seismically observed layers and the occurrence of the magnetic regimes for two inner core ages; one with a nucleation at 1.4 Ga and one at 0.6 Ga, corresponding to an average CMB heat flux of 7.6 TW and 16.7 TW respectively.

Although we currently cannot differentiate between these two inner core ages considering our results alone, they do show that a relation between inner core structure and the behaviour of the magnetic field is possible, and suggest that seismic observations of inner core structure might provide new and independent insights into the magnetic field and its history.
Rotation in civil engineering structures: analysis of the City-Hall (Grenoble) building using 3C and 6C sensors
Authors: Guattari Frédéric , Gueguen Philippe , Aubert Coralie , Laudat Théo
Published: March 2020

Civil engineering structures are often modeled as single-degree-of-freedom systems, taking into account only horizontal translation forces. However, their response to seismic loading produces rotational forces that can in some cases generate considerable stresses and resultant damage. These rotational forces are essentially related to (1) rotational deformation about both horizontal axes (rocking), resulting from ground-structure interactions, considering the structure as a rigid body; (2) rotation about the vertical axis (torsion), essentially activated when the centre of mass (i.e. where the seismic inertial forces apply) is offset from the centre of rigidity (i.e. where the elastic forces apply). The simplified model including the rotations of the ground-structure interaction is based on modal decomposition, i.e. each component of the motion is assumed to be independent of the others. Thus, in structures, only translational sensors are usually installed and the rotational components are evaluated via the spatial derivatives of the horizontal and vertical components. However, there are combinations of translations and rotations and rotations can only be evaluated by measuring all 6 components of motion (3 translations and 3 rotations). In this presentation, a simple analysis is made to explain the rotations observed in the City Hall building in Grenoble (France), a 12-storey reinforced concrete building. This building has been continuously monitored for 10 years, with 3-component accelerometers located at the bottom and top. Modal decomposition is performed using ambient vibrations. A set of earthquake records is then used to evaluate rotations using derived functions and compared with the records of a 6C rotation sensor temporarily installed at the top of the building. The comparison between the direct rotation measurement and the spatially derived rotation is performed. 
Brazilian Equatorial Margin: evidences of magmatic intrusion and alteration of host rock from well data
Authors: Aquino da Silva Andre , Reyes Perez Yoe Alain , Vital Helenice
Published: March 2020

The mechanisms of magmatic intrusion is very complex and are commonly associated to pristine unconformities (weak spots) on the crust that ease its emplacement on the form of sills or dikes. When occurring on the Oceanic crust these weak spots may led to the formation of volcanic islands (such as Fernando de Noronha, on the Brazilian Equatorial Margin-BEM), submarine highs. Alignment of such features are related to Plate motion and the set of volcanos of Fernando de Noronha Ridge are considered a consequence of the westward motion of the South American Plate. Occurrence of magmatic rocks were found on a set of offshore wells at different depths and away of submarine highs. These magmatic emplacement suggests be related to a deep plume-fed mechanism which is the source of all sills found on the wells, as well as the volcanic highs occurring of the BEM. The lateral extents of the sills is greatly influenced by the presence of faults when preceding the intrusion, during which also occurred incorporation of parts of the host rock as xenoliths. On the well logs it is possible to observe changes on sonic slowness for the same lithotype when close to the sills, which indicates rock alteration due to the magmatic intrusion.
Impact of the current feedback on the representation of tropical cyclones in coupled models
Authors: Maillard Lisa , Boucharel Julien , Renault Lionel , Arsouze Thomas
Published: March 2020

Tropical Cyclones (TCs) are among the most destructive natural phenomena on Earth and severely impact nearly a billion people. Coupled models have become a necessary tool to improve our knowledge on those natural hazards. Improving their ability to statistically represent TCs is of prior importance. In the present study, we investigate the impact of the mechanical interaction between the surface oceanic current and the atmosphere (i.e., the Current FeedBack, CFB) on the statistic of TCs in different basins. We perform sensitivity experiments using the EC-Earth model in its High-Resolution version (1/12˚), by switching on and off CFB. As CFB has been shown to strongly improve the realism of the oceanic circulation at both large scale and mesoscale, we expect an improvement, i.e., a better realism, of the statistical TCs representation when CFB is taken into account in the model. Improving coupled models will help design forecast schemes with lead times longer than those currently provided by operational forecasts centers.
Drivers and responses of ecosystem processes at the Collelongo beech forest: main results and lessons learned over 30 years of research and monitoring in a period of changes
Authors: Matteucci Giorgio , Collalti Alessio , D'Andrea Ettore , De Cinti Bruno , Gavrichkova Olga , Guidolotti Gabriele , Manca Giovanni , Mazzenga Francesco , Rezaei Negar , Scartazza Andrea , Valentini Riccardo , Scarascia Mugnozza Giuseppe
Published: March 2020

The long-term research and monitoring site of Collelongo - Selva Piana has been established in 1991 (Abruzzo Region, Central Italy, 1560 m elevation) in the framework of a project on ecology and silviculture of European beech. In 1993, the site was the first forest in Europe where canopy fluxes started to be measured with the eddy covariance technique. Since then, the site has been involved in several of the most important networks and projects, including ICP Forests, Euroflux, CarboEurope-IP, FluxNet and, in 2006, joined the Long Term Ecological Research network (LTER).

Measurements at the Collelongo site bridge two centuries, starting right at the end of the WMO and IPCC climate reference period (1961-1990) and extending, in continuous, over a period of great changes (the three warmest ever decades occurred since then), including a number of extreme events (heat waves, droughts, late frost). During these thirty years, more than 50 researchers from different parts of the world performed direct measurements at the site, flux datasets from the site (code IT-Col) had more than 1500 unique downloads and it is estimated that more than 300 people used the data for producing more than 150 ISI papers.

We will briefly present the main results on different ecosystem processes (Phenology, Net Primary Production, Carbon Allocation, Net Ecosystem Exchange, Nutrient and Water Cycling) emphasizing responses to drivers, including legacies from the past. Over these thirty years, the growing season length increased significantly (1.33 day yr-1 from 2000 to 2015), the studied beech forests absorbed between 120 and 150 tC ha-1 and showing plasticity and resilience to changing climatic conditions. However, increasing warming, drought and extreme events may impair adaptation capacity. In this respect, modelling offers a tool to evaluate long-term responses, including possible management options to increase both adaptation and resilience capacities.
Title: Urban air pollution monitoring at micro-, local and meso- scales using Pandora instrument
Authors: Spinei Elena , Geddes Jeffrey , Adams Taylor , Müller Moritz , Gebetsberger Manuel
Published: March 2020

Increasing urbanization worldwide raise serious concerns about urban air quality and its effects on large human populations. This study presents application of the Differential Optical Absorption Spectroscopy technique to multi scale urban air quality (NO2) monitoring. A Pandora spectroscopic instrument (SciGlob Inc) has been deployed on top of a 30 m building in Boston, MA, USA, since September 2019. It performs over the roof sky scans (local to meso scales), into the street canyon "target" (micro-scale), and direct sun measurements. In situ NO2 measurements are also being conducted on top of the roof (co-located with Pandora) and at the street level near the "target" building. NO2 spatial and temporal heterogeneity within different scales is discussed.
The 17-year ROM SAF radio occultation climate data record
Authors: Lauritsen Kent B. , Gleisner Hans , Nielsen Johannes K. , Syndergaard Stig
Published: March 2020

The Radio Occultation (RO) technique is based on measurements of phase shifts of GNSS radio waves by an instrument onboard a low-Earth orbiting satellite. The processing of the measurements yields the refractive index of the Earth’s atmosphere, from which the temperature, pressure, and humidity fields can be retrieved. It is a limb-sounding technique, with a high vertical resolution, and with observational information retrieved from near-surface to the upper stratosphere. Numerous studies have demonstrated the accuracy of GNSS Radio Occultation (RO) data, and their usefulness as a stable climate reference. Homogeneity of the data records are obtained by reprocessing of the data using uniform processing software and a priori data throughout the length of the climate record. We here present results from a validation of the 17-year ROM SAF RO Climate Data Record (CDR), based on a new reprocessing of Metop, CHAMP, GRACE, and COSMIC data using excess-phase and amplitude data from EUMETSAT (the Metop mission) and UCAR/CDAAC (the CHAMP, GRACE, COSMIC, and Metop missions).

A central issue for the generation of RO-based CDRs is whether data from different satellite missions can be combined to form long time series of multi-mission data. This presentation explores the consistency of gridded monthly-mean data from different RO missions through comparison with ERA-Interim reanalysis data, and through a study of mission differences during mission overlap periods. It is shown that within a core region from the upper troposphere to the middle stratosphere, roughly 8 to 35-40 kilometers (depending on latitude and geophysical variable), there is a high consistency amongst the RO missions, allowing for the construction of long-term stable data sets for use in climate studies and climate monitoring.
Flexible energy systems for planning the world’s main copper mines considering geographical conditions
Authors: Moreno Leiva Simon , Haas Jannik , Nowak Wolfgang , Junne Tobias
Published: March 2020

Energy systems of the future will be highly renewable, but building the required infrastructure will require vast amounts of materials. Particularly, renewable energy technologies are more copper-intensive than conventional ones and the production of this metal is intensive in energy and emissions. Moreover, as mineral resources are being depleted, more energy is required for their extraction, with subsequent increase in environmental impacts. Highly stressed and uncertain water resources only worsen this situation.

In this work, we will first provide a comprehensive review of the limited available energy planning approaches on copper mines, including transferrable learnings from other fields. Our second contribution is to compare the influence of different geographical locations on the optimal design of energy systems to supply the world’s main copper mines. For this, we use a linear energy system optimization model, whose main inputs are hourly time series for solar irradiation and power demand, and projections for energy technology costs and ore grade decline. Our third contribution is to propose a multi-vector energy system with novel demand-side management options, specific to copper production processes, including water demand management, illustrated on a case study in Chile (where mining uses a third of the nationwide electricity).

In the first part, the review, we learned that energy demand models in copper mines have only coarse temporal and operational resolutions, and require major improvements. Also, demand-side management options remain unstudied but could promise large potentials. In general, the models applied in copper energy planning seem overly simplistic when contrasted to available energy decision tools.

For the second part, we observed that in most locations, using local photovoltaic power not only lowers future electricity costs but also compensates for increased energy demand from ore grade decline. Some regions gain a clear competitive advantage due to extremely favorable climatic conditions.

In the third and final part, regarding the demand-side management, we saw how the geography and the spatial design of the mines strongly influence the available options and their performance. Jointly planning flexible water and energy supply seems to be particularly attractive. Also, there is space for smart scheduling of maintenance of the production lines, the hardness of the rock feed, oxygen production, and the hauling (rock transport) fleet.

As an outlook,  we highlight the need for consideration of lifecycle impacts as a design goal, and to further develop demand model’s and their flexibility on the mining side. We expect that implementing these smarter approaches will help secure a cleaner material supply for the global energy transition.
Massive High-Angle Normal Faulting at distal magma-poor margins: examples from South Atlantic
Authors: Denis Michaël , Ballard Jean-François
Published: March 2020

Seismic imaging of very distal margins enabled to evidence seaward-verging normal faults with slip displacements up to 6000 meters, in several areas of both African & Brazilian magma-poor margins.

Interpretation of deep seismic profiles, including 3D seismic, time- & depth-migrated, evidence sharp depth variations of the Moho, close to areas where subcontinental mantle exhumed further to successive activation of Low-Angle Normal Faults and large detachement faults.

The sharp Moho depth variations are related to giant High-Angle Normal Faults (HANF) which had offset the Moho itself and may have rooted close to the base of the serpentinized mantle. The faults are sealed within the salt, enabling to date it Late Aptian in age.

The close synchronicity between HANF activity and salt deposition reflects some dramatic changes of depositional environments, subsidence and deformation processes at the scale of the margin, especially as salt deposition is also closely related to significant increase of magmatic additions in the ultra-distal parts of the margin.

These changes are very likely related to the lithospheric break-up process and support the post-detachement timing of activation of the HANF interpreted from cross-cutting relationships on the seismics.

The evolutionary model for HANF proposed is supported by field evidence, seismic analogs and thermomechanical models: it invokes thermal, isostatic, rheologic, tectono-magmatic processes, and documents the context of South Atlantic salt deposition.
Convolutional neural network-based automatic root length measurement in noisy rhizosphere images
Authors: soffer Adam , Parthasarathi Theivasigamani , Lasri Amir , Hadar Ofer , Rewald Boris , Bodner Gernot , Baykalov Pavel , Ephrath Jhonathan , Lazarovitch Naftali
Published: March 2020

The use of minirhizotron (MR) imaging systems is gaining popularity, resulting in a large amount of collected images—which need efficient and accurate processing for root trait extraction. This study proposes a neural network-based solution for automatic measurement of root length in images taken by MR systems. Current root length measurement techniques involve two steps; manually operating the MR for taking the images, and manually annotating roots in front of a noisy rhizosphere ‘background’ with a dedicated software. As the analysing process is extremely time consuming, automation can both lower the costs and facilitate greater temporal resolution.

Using convolutional neural networks (CNN) in image classification tasks has become very common due to its simplicity, yet regression tasks are still considered difficult. We propose a new model that combines the strength of conditional learning, transfer learning and bagging in order to achieve a precise regression. The dataset used holds 12,000 highly diverse images of 5 tomatoes cultivars, which were collected by a BARTZ minirhizotron camera over a period of 4 months.

Initial results show a success rate of 75% accuracy with 33 mm Mean Absolute Error (MAE). Error analysis shows that large errors occur on images with either a very high or a low root length density. Additionally, a separate model was designed and tested on selected subsets of the data by using a synthetic data generator. Results show that MAE decreases to 10 mm, which is equivalent to 90% accuracy.

Results suggest that this method has great potential to facilitate fully automatic root length measurement on noisy rhizosphere images. Future work will validate the proposed model with a larger datasets comprising of various plant species, soil types and MR imaging systems.
Opportunistic sensing in hydrometeorology
Authors: Uijlenhoet Remko , de Vos Lotte , Overeem Aart , Leijnse Hidde
Published: March 2020

Traditionally, hydrologists have relied on dedicated measurement equipment to do their business (e.g. rainfall-runoff modeling). Such instruments are typically owned and operated by government agencies and regional or local authorities. Installed and maintained according to (inter)national standards, they offer accurate and reliable information about the state of and fluxes in the hydrological systems we study as scientists or manage as operational agencies. Such standard instruments are often further developments of novel measurement techniques which have their origins in the research community and have been tested during dedicated field campaigns.

One drawback of the operational measurement networks available to the hydrological community today is that they often lack the required coverage and spatial and/or temporal resolution for high-resolution real-time monitoring or short-term forecasting of rapidly responding hydrological systems (e.g. urban areas). Another drawback is that dedicated networks are often costly to install and maintain, which makes it a challenge for nations in the developing world to operate them on a continuous basis, for instance.

Yet, our world is nowadays full of sensors, often related to the rapid development in wireless communication networks we are currently witnessing (notably 5G). Let us try to make use of such opportunistic sensors to do our (hydrologic) science and our (water management) operations. They may not be as accurate or reliable as the dedicated measurement equipment we are used to working with, let alone meet official international standards, but they typically come in large numbers and are accessible online. Hence, in combination with smart retrieval algorithms and statistical treatment, opportunistic sensors may provide a valuable complementary source of information regarding the state of our environment.

The presentation will focus on some recent examples of the potential of opportunistic sensing techniques in hydrology and water resources, from rainfall monitoring using microwave links from cellular communication networks (in Europe, South America, Africa and Asia), via crowdsourcing urban air temperatures using smartphone battery temperatures to high-resolution urban rainfall monitoring using personal weather stations.