bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of Shifting Subtropical Highs on North American Climate
Authors: Schmidt Daniel , Grise Kevin , Amaya Dillon , Miller Arthur
Published: March 2020

Numerous observational studies have found that the Hadley cells have expanded poleward in both the Northern and Southern Hemispheres, and model results suggest that such expansion is likely to continue throughout the 21st century as a result of global warming.  This has led to concerns about future impacts of Hadley cell expansion, including a poleward shift of the subtropical dry zone.  However, climatic changes associated with Hadley cell expansion are zonally asymmetric—especially in the Northern Hemisphere—suggesting that a more regional focus may be necessary.  In this study, we consider the influence of the Northern Hemisphere subtropical highs, and contrast this with the influence of Hadley cell expansion. 

Specifically, we consider the North Pacific and North Atlantic subtropical highs and define, for each high, three indices representing longitude, latitude, and strength.  We find that 21st century trends in variables as diverse as precipitation, sea-level pressure, winds, and ocean upwelling in eastern boundary currents are all driven more by the trends of these subtropical high indices than by the expansion of the Hadley cell.  We conclude that 21st century trends in subtropical high positions and strengths are crucial to understanding the future of Northern Hemisphere climate.  Further work will be needed to determine the dynamical drivers of these subtropical high trends.  
Assessment of NOA risk for the excavation of a highway tunnel system ("Gronda di Genova", Italy): from NOA-oriented geological model to asbestos quantification
Authors: Piana Fabrizio , Avataneo Chiara , Barale Luca , Botta Serena , Compagnoni Roberto , Cossio Roberto , Marcelli Igor , Tallone Sergio , Turci Francesco
Published: March 2020

For a reliable evaluation of the geo-environmental risk related to the presence of naturally occurring asbestos (NOA) in rocks excavated for large infrastructural projects, a proper procedure has to be followed in order to achieve:

1) the definition of a detailed geological model, tailored on NOA-related issues;

2) a representative sampling;

3) a reliable quantitative determination of asbestos content in rock samples.

Here we describe the approach followed for the evaluation of the NOA content for the excavation of a complex highway tunnel system (“Gronda di Genova” NW Italy), in NOA-bearing meta-ophiolite rocks. The NOA-oriented geological model has been constrained by the individuation of the main “NOA-related petrofacies” —i.e., classes of rocks with common lithological, structural and NOA content features—, and by the identification of “homogeneous zones” – i.e. geological units into which the NOA petrofacies are distributed. Implementation of Gy’s theory on sampling was used and here described to maintain statistical validity during sample processing from the primary rock sample to the analytical sample. SEM-EDS procedure for the quantitative determination of NOA content was improved with an error analysis delivering the minimum number of fibers to be measured to achieve the best analytical results.

The obtained results allowed the prediction of the NOA hazard in terms of risk zonation along the tunnel section and for the evaluation of the amount of asbestos-bearing spoil to be excavated and managed.
Drilling the Tore seamount- Archive of a natural oceanic sediment trap
Authors: Lebreiro Susana M. , Nave Silvia , Antón Laura , Michel Elizabeth , Kissel Catherine , Waelbroeck Claire , McCave Nick , Hodell David , Flores Jose-Abel , Martinez-Ruiz Francisca , Martrat Belén , Roque Cristina , Piotrowski Alex , Skinner Luke , Sierro Francisco , Terrinha Pedro , Cornen Guy , Reguera María Isabel , Lozano-Luz Rocío , Bravo Natalia
Published: March 2020

Located 300 km off West Iberia in the open NE Atlantic Ocean, the Tore seamount emerges from the 5.5 km surrounding abyssal plains to a summit rim at 2.2 km, which has an elliptical crater-like shape with a central depression 100 km in diameter. The ~5.5 km depth of the Tore internal basin is connected to the surrounding deep ocean basin by a single narrow gateway down to 4.3 km depth. This basin is exceptional because it is 1) a giant sediment-trap for vertical fluxes, with sediments unaffected by deep currents and erosion, containing a record of enhanced biogenic subtropical productivity during deglaciations, which can be examined mechanistically, 2) a natural laboratory to examine carbonate dissolution at 5.5 km water depth constrained by NADW deep ventilation during glacials, and 3) an excellent location to test sediment processes distant from continental margins and understand triggering mechanisms of downslope flows in the open, deep ocean. Not many cores have been recovered in the area at such 5.5 km depth and unite this singular environment. At the larger scale of North Atlantic circulation and productivity, the semi-isolated Tore seamount is a most valuable site to assess crucial scientific hypotheses related to thermohaline circulation, carbon cycling and climate variability. These challenging questions are framed in the IODP Initial Science Plan illuminating Earth´s Past, Present and Future, 2013-2023, theme Climate and Ocean Change.

Our APL applies for drilling one site in the middle of the Tore seamount at 5.5 km depth, to retrieve a complete Quaternary sedimentary sequence (180 m long). This carbonate rich archive will be compared with records available in the Northeast Atlantic and to be recovered during Expedition #771-Full2 (Hodell et al.).

We present results from a 24 long giant Calypso core taken in the APL-site proposed which covers 430 thousand years and 5 glacial-interglacial cycles (Spanish project “TORE5deglaciations”, CTM2017-84113-R, 2018-2020).
Variability of nitrogen oxide lifetimes and emission fluxes estimated by Sentinel-5P observations
Authors: Lange Kezia , Richter Andreas , Burrows John P.
Published: March 2020

Satellite observations of the high-resolution instrument TROPOMI on Sentinel-5P make it possible to measure nitrogen dioxide (NO2) at city level and even to quantify the variability of NOx emissions and lifetimes on a seasonal and daily basis.
NO2 is an air pollutant and especially in cities of particular importance due to the large number and strength of emission sources in combination with people living nearby exposing their health to the polluted air. To quantify nitrogen oxide emissions and lifetimes with their variability in space and time, satellite data is especially suited as it provides daily global coverage and large number of measurements. The TROPOspheric Monitoring Instrument (TROPOMI) on Sentinel-5P, launched in October 2017, provides, thanks to its higher spatial resolution when compared to previous satellite instruments, the possibility of detailed investigations on lifetimes and emissions of air pollutants.
Two years of TROPOMI NO2 data with a spatial resolution of up to 3.5 km x 5.5 km together with ECMWF ERA5 wind data are analyzed. The NO2 data around a source is linked to the ERA5 wind data and rotated to a uniform wind direction to get clear emission patterns. Out of these two-dimensional maps of the mean NO2 distribution, one dimensional line densities are calculated by integration across wind direction. Lifetimes and emission fluxes are calculated for different NOx sources such as cities and power plants distributed over the world. They are compared among each other and to bottom-up emission inventories. Seasonal variability and weekday versus weekend effects in lifetimes and emissions are discussed.
ICDP project Drilling the Eger Rift – present status and further plans
Authors: Dahm Torsten , Fischer Tomas , Woith Heiko , Hrubcova Pavla , Vicek Josef , Korn Michael , Krüger Frank , Horalek Josef , Vylita Tomas , ScienceTeam ICDP-Eger
Published: March 2020

Within the ICDP-Eger drilling project we are developing one of the most modern and comprehensive laboratories at depth worldwide to study the interrelations between the flow of mantle-derived fluids through the crust and their degassing at the surface, the occurrence and characteristics of crustal earthquake swarms, and the relation to the geo-biosphere. The Cheb basin located in the western Eger Rift at the Czech-German border provides an ideal natural laboratory for such a purpose. In October 2016 the ICDP proposal was accepted for complementing two existing shallow monitoring wells with five new, distributed, medium depth (<400 m) drill holes F3 and S1-S4.

The resulting natural laboratory at depth will comprise five drilling sites for studying above mentioned phenomena. The F1-F3 drillings form a unique facility of three wells at one site within an active CO2 mofette of Hartoušov for continuous recordings of fluid composition and fluid flow rate, as well as for intermittent GeoBio fluid sampling. Drillings S1-S4 are planned for seismological monitoring to reach a new level of high-frequency, near source observations of earthquake swarms and related phenomena such as seismic noise and tremors generated by fluid movements. Instrumentation of the seismic wells S1-S3 will include 8-element geophone chains and a bottom-hole broadband sensor. The borehole sensors will be complemented at S1 by small-scale surface array of approximately 400 m diameter to obtain truly 3D-array configurations. If possible, broadband surface stations and other sensors will be added to each drill location.

So far, we have completed drillings at sites S1, S2 and S3, with depth of 402, 480 and 400 m. The drilling of S4 is planned in 2020 at one of the recently discovered Maars at the Czech-German border region. Drilling F3 was completed in September 2019 at a depth of 239 m. It has reached several over-pressurized, CO2 bearing layers. The three boreholes have been connected by underground tubes system to the nearby field laboratory equipped by flowmeters and mass spectrometers allowing for long time precise monitoring of the degassing process. The S1 borehole (Landwust) will be instrumented in January 2020 by a test geophone chain allowing, along with the DAS fibre-optic cable installed behind the casing, to carry out a VSP measurement.

In our presentation we provide information on the status of drillings, sensor installation and plans for the complete monitoring and data handling concept.
Global long-term sub-daily reanalysis of fluvial floods through high-resolution modeling
Authors: Yang Yuan , Pan Ming , Lin Peirong , Beck Hylke , Yamazaki Dai , Lu Hui , Yang Kun , Hong Yang , Wood Eric
Published: March 2020

Flood is one of the most devastating natural disasters of severe societal, economic, and environmental consequences. Understanding the characteristics of floods, especially at fine spatial and short temporal scales, can be critical for improving forecast and risk management efforts. Due to the limited availability, in-situ observations have been inadequate for meeting the challenges at global extent. Existing global flood modeling efforts also lack the sufficient spatial/temporal resolutions for capturing rapid/local flood events, e.g., those developed in less than a day. Here we implement a carefully-designed modeling framework to reconstruct global river discharge at very high resolution (5-km and 3-hourly for runoff calculation and ~2.94 million river reaches derived from 90-m DEM for river routing) for 40 years (1979-2018). The Variable Infiltration Capacity (VIC) model with calibrated parameters, is coupled with the Routing Application for Parallel computation of Discharge (RAPID), serving as the core of the modeling framework. The state-of-the-art merged precipitation product, Multi-Source Weighted-Ensemble Precipitation (MSWEP) and flowlines vectorized from the MERIT Hydro are used. Pixel-level model calibration and distributional bias correction are performed against global runoff characteristics derived from observations and machine learning. Skill assessments are carried out both globally at daily sale and over contiguous U.S. (CONUS) at 3-hourly scale, using both general discharge performance metrics (Kling-Gupta Efficiency and it three components) and sub-daily flood-specific metrics (probability of detection, false alarm rate, flood volume error, peak magnitude error, timing error, etc.). The work here aims to provide some first-time understanding of local scale rapid flooding over the global domain. We also expect to learn more about the modeling tools developed for analyzing/monitoring fine scale flooding globally – their efficacy and lack thereof, why, and where to improve.
Large landslides database along the Central Western Andes (15º - 20º S): constraints on mass-movement development and implications on relief evolution
Authors: Fabrizio Delgado , Swann Zerathe , Stéphane Schwartz , Carlos Benavente
Published: March 2020

The western flank of the central Andes presents an exceptional concentration of large paleo-landslides (v> 100*106 m3), most of which being well-preserved morphologies due to low erosion and weathering related to the hyper-arid climate of the Atacama Desert since the Miocene. First order questions are pending about the triggering of those mass-movements, their dynamics, their locations and their roles on the Andean relief evolution. Previous studies included geomorphological analysis and few dating on individual landslides (e.g. in Peru: Margirier et al., 2015; Crosta et al., 2014; Zerathe et al., 2017; Delgado et al., 2020; e.g. in Chile: Strasser and Schlunegger , 2005; Pinto et al., 2008; Crosta et al., 2017). Preliminary regional mapping have been attempted in Peru (Geocatmin-INGEMMET and Audin & Bechir 2006) and in Chile (Matther et al., 2014 and Crosta et al., 2014).

Here we proposed a new and exhaustive mapping of large landslides of the Western Andes updating and homogenizing the previous works. The considered area locates between latitude 15° and 20°S, from the coast to the mean elevation of the Altiplano (~5000 m a.s.l). The landslide mapping was done by using Google Earth and DEMs (TanDEM-X and Pléiades). We mapped polygons (surface area > 0.1 km²) corresponding to destructured areas and strictly including the evidence of major landslide scarps (cliffs, unusual slope-breaks, etc.) and its sliding mass (offset lithology, boulders fields, etc.).

We identified more than 700 landslides, distributed into three main typologies: (1) deep-seated rockslide (DSR) showing “in-mass” displacement; (2) rock-avalanche (RA) with typical granular-flow morphologies (e.g. levees, boulders fields) and (3) destabilizations associated with both dynamics. This GIS database allows statistical analysis and interpretations crossing the landslide distribution and typologies versus relief properties, geology-lithology, long-term uplift, dating, etc. Preliminary analysis of this database shows that spatial distribution of mass-movements is not homogeneous. Instead, we observed cluster of mass-movements following the main valleys or canyons. They mainly located at elevation between 1500 and 2000 m a.s.l. Interestingly, the largest landslides (surface area > 50 km2) are disconnected to fluvial incision. They occurred within interfluve areas. Few of the largest landslides cover alone more than 30 % of the total cumulated landslide area in this region and, on their own, might contribute at a first order to the relief erosion.
Volcanic hazard assessment and vulnerability analysis at San Miguel Volcano, El Salvador.
Authors: Jimenez Diana , Becerril Laura , Bartolini Stefania , Martí Joan
Published: March 2020

Despite being one of the most active volcanoes in El Salvador, San Miguel is surrounded by important population nuclei and infrastructures. We used existing historical records of past eruptive activity, available geological knowledge and monitoring data gathered over the past fifteen years to conduct the first comprehensive, long-term hazard assessment of this volcano, aimed at helping to reduce the potential risk it poses. We applied probabilistic methods (QVAST and HASSET) specifically designed for volcanic hazard assessment to conduct two hazard analyses, one with a forecasting time window of two years using information on volcanic activity over the past 430 years (historical period), and another with a forecasting window of six months, with information from the past 16 years (monitoring period). Using the information from this hazard assessment, we simulated: (1) the five most likely scenarios (ashfall scenarios, short-medium extent, and VEI 1-2); (2) other probable scenarios related to lava flows, based on the historical record of the volcano; (3) other possible scenarios related to PDCs with similar characteristics to those that occurred during its geological history; and (4) the most hazardous scenario (ashfall, lava flow, PDC) that has been identified from its geological record. Finally, we construct a qualitative integrated volcanic hazard map through the combination of the simulated scenarios. Finally, we developed an exposure analysis of the San Miguel volcano area by considering population distribution, land use, private houses, official buildings (hospitals, schools, etc.), and communication infrastructure, for the different hazard scenarios. In the particular case of private houses and official buildings, we estimated a Vulnerability Index for the hazardous areas, applying the Physical Vulnerability Methodology based on the characterization of the type of construction materials of walls and roofs.  This approach identifies the elements at risk according to each potential hazard, thus providing the authorities with a comprehensive tool to better understand the problem and to define emergency plans to minimize risk.

This research has been partially funded by Grants I-COOPA20161 (CSIC) and EU (DG ECHO) Project EVE n. 826292
Experimental and numerical study of the stability of barge-type floating offshore wind turbine platform
Authors: Yang Wen-Hsuan , Yang Ray-Yeng , Chang Tzu-Ching
Published: March 2020

The global wind energy has developed over 30 years. However, as the offshore wind power installed within 50 to 60 meters of water depth is gradually saturated. Offshore wind power installations are progressively shifting from nearshore to offshore. With the increment of water depth, the difficulties and the cost of the offshore wind power installations are also increased, makes the fixed-bottom type of structures less favorable in deep water areas and accelerate the development of the floating type offshore wind platforms. Floating offshore wind platforms can be classified into main three types: spar buoy, semi-submersible, tension-leg platform (TLP) according to reaching stability. In addition to these types, a barge-type floating platform, a new design concept, can reduce the dynamic motion of the platform by its moon pool. In this study, the hydrodynamic performance of a floating barge platform with a moon pool supports an NREL 5MW wind turbine and with a mooring system at a water depth of 50 meters was investigated. This numerical simulation was applied to analyze the hydrodynamic performance of the platform using ANSYS Aqwa software. Experimental tests in a flat water tank were conducted at National Cheng Kung University, Tainan Hydraulics Laboratory (THL). The model is a 1:64 scaled barge platform and the turbine is scaled down from the NREL 5MW. Three tests of the platform were conducted, including the free decay test, regular wave test, irregular wave test with wind operation and parking. The experimental data was analyzed to get the natural period through the free decay test. The numerical simulation results were compared with the 1:64 scaled experiment to observe the motions and Response Amplitude Operator (RAO) of surge, heave and pitch motions on the barge platform with moon pool. The floating barge platform, designed in this study, will be tested in the open sea to ensure it can withstand - extreme wave conditions such as typhoons.
The removal of As(V) ions by lime-modified fly ash and reuse of the exhausted adsorbent as an additive for construction material
Authors: Karanac Milica , Đolić Maja , Pavićević Vladimir , Marinković Aleksandar
Published: March 2020

Coal thermal power plants (TPP) actively generate numerous solid combustion by-products, including fly ash and bottom ash. These TPP by-products have already found use in a variety of civil engineering applications, such as a substitute for sand and gravel in structures, as well as a binding component in certain types of cement (generally, concrete and masonry). Furthermore, such by-products have become a subject of increasing interest in environmental engineering as a low-cost and effective adsorbent for the removal of organic pollutants and heavy metals from wastewaters.

In order to minimize the impact of material cost, novel solutions for the development of a high capacity and long-term adsorbent have provided a high performance adsorbent for practical applications. This study is focused on the use of modified fly ash (MFA) activated by lime (Ca(OH)2) as an effective and low-cost adsorbent for the removal of As(V) ions. The adsorption capacity of the MFA adsorbent was found to be 35.40 mg g-1, while the kinetic and thermodynamic parameters indicated a spontaneous and endothermic process. Due to the low desorption potential of the exhausted adsorbent (MFA/As(V), their effective further material reuse was established to be feasible. The reuse of the exhausted adsorbent was obtained through pozzolanic MFA particles and Ca(OH)2, thereby formulating a construction material of a cementitious calcium-silicate hydrate. The toxicity leaching test (TCLP) and mechanical properties of the new construction material containing exhausted MFA (CM-MFA/As(V)) confirm its safe use in the laboratory as well as its semi-industrial application.

The specific objectives of this study have been: (i) to improve the adsorption performance of the MFA; (ii) to evaluate the material’s equilibrium, as well as the process’ kinetic and thermodynamic aspects, including  estimating its limiting step; and (iii) to investigate the possible reuse of the exhausted adsorbent in the production of construction materials. The kinetic data were successfully fitted by a pseudo-second-order equation and the Weber-Morris model. The metal-desorption experiments performed on the exhausted FA and MFA indicate a low recovery of the selected pollutants.

The major outcome of this study, indicates that double-valorization of fly ash opens new directions for waste management toward reuse in effective practical applications; i.e., for actual water –purification systems, as well as in the production of construction material.
The soil loss by water erosion at the European part of Russia
Authors: Maltsev Kirill , Yermolaev Oleg
Published: March 2020

A quantitative assessment of the potential soil erosion on arable land in the European part of Russia (EPR) was carried out. The total area of arable land of the EPR is about 650,000 km2. The majority of the population of Russia lives here - about 95 million people. The level of generalization of work is regional and corresponds to a scale of 1: 500,000.

As a research method, mathematical modeling based on modified for Russia’s natural conditions USLE equation for calculating potential soil loss from erosion. Another leading method for assessing soil erosion and presenting results is GIS. A raster model of data presentation was used in the calculations, including a model of slope angles, slope lengths, soil erodibility, erosive rainfall potential, water reserves in snow, intra-annual redistribution of rainfall, and land use types.

New data have been obtained on the value of soil erosion losses during melt and storm runoff periods and total annual losses. An electronic map of soil erosion losses on arable lands of the European part of Russia has been compiled, which allows determining spatial features of soil erosion rates.

The average soil erosion losses, taking into account the soil-protective coefficients of agricultural crops for the study area, are 4.04 t / ha per year. In annual soil losses due to erosion, storm 3.78 prevails, soil loss from melt water is almost an order of magnitude less - t / ha 0.26. About half of the territory is located in conditions under which the soil loss does not exceed 0.5 t / ha per year.

The rate of potential soil erosion on arable land in the European part of Russia naturally decreases in the direction from the taiga-forest to the steppe landscape zone. The band of maximum potential soil erosion of the west-east sub-latitudinal strike is clearly distinguished, confined to the subzone of mixed and broad-leaved forests with very high plowing. A comparative analysis of our data and data obtained in the mid-1980s showed a reduction in soil loss from water erosion in all landscape zones. In addition, a comparative analysis of the data obtained by us and the data for the European Union was carried out, which showed that the soil losses on the EPR are slightly higher.
Microstructure-based modeling of snow using the material point method and finite strain elastoplasticity
Authors: Blatny Lars , Löwe Henning , Wang Stephanie , Jiang Chenfanfu , Gaume Johan
Published: March 2020

The mechanical response of snow depends on its microstructural geometry. Parameters such as porosity and orientation (degree of anisotropy) are examples of microstructural parameters that can affect snow mechanical properties. Numerical simulations of snow microstructure obtained from X-ray computer tomography have aided researchers in investigating the elastic response and strength of snow. However, we lack insight into the post-peak and plastic response of snow, which in most previous studies have been oversimplified assuming (quasi-)brittle behavior. We propose studying both the elastic and post-peak behavior using the material point method (MPM), a hybrid Eulerian-Lagrangian continuum numerical method. A major advantage of MPM compared to the (classical) finite element method (FEM) is its ability to handle large deformation processes. Moreover, as a continuum method, it is significantly less computational expensive than the discrete element method (DEM). We independently study the influence of the microstructural parameters on macroscopic quantities, such as elastic modulus, strength, energy release rate and plasticity index, in mixed-mode shear-compression loading simulations. This is accomplished by using the leveled gaussian random field (GRF) approach to generate snow samples with desired microstructural properties. The ice matrix of the microstructure is modeled in the elastoplastic framework with a strain-softening Drucker-Prager failure criterion. Based on the relationships discovered through these numerical experiments, we aim to develop a microstructure-based homogenized constitutive snow model. This study will contribute to improve large-scale snow mechanical models with applications in the simulation of e.g. snow slab avalanche release, avalanche dynamics and snow-tire interaction.
Sustainability of water resources in Andorra under global change: The effects of climate and socio-economic changes in the future of water resources
Authors: Pesado-Pons Cristina , Travesset-Baro Oriol , Zabalza Javier , López-Moreno Juan Ignacio , Pons Marc
Published: March 2020

Water resources have a fundamental value for both ecosystems and society. However, changes in climate, population, consumption patterns, land use and urbanization are affecting its quality and future availability. In Andorra, a country located in the middle of the Pyrenees, the confluence of climate change and a socioeconomic model with an important weight of tourism industry based on an intensive use of water could threaten the future sustainability of water resources. 

This paper analyses the water resources of Andorra and its future sustainability using the Water Evaluation And Planning system (WEAP) modelling tool. 

The WEAP-Andorra model presents an initial estimate of the national water demand segregated into the main water consumers of the country (tourism, residential, primary sector and power generation). It explores the future evolution of water resources combining climatic and socioeconomic scenarios such as evolution of the population, tourism, power generation plans and land use patterns.

Results of scenarios show that in general terms and at country scale the impact of climate change will not compromise the future water demand. However, in some locations and in specific periods or seasons it could be some challenges to give response to all the demands and rise tensions about what water uses should be prioritized, especially between tourism and ski resort and resident uses.   

The WEAP model presented in this paper is demonstrated a useful tool to support management, decision-making and the design of policies for sustainable water management and adaptation to climate change.
Role of catchment and climate characteristics in Hydrological Drought parameters and propagation in major river basins of India
Authors: Bhardwaj Kunal , Mishra Vimal
Published: March 2020

The understanding of the propagation of meteorological droughts to hydrological droughts is an important phenomenon to take pre-emptive action to mitigate the effects of droughts. In this study, we have correlated the Standardized Streamflow Index (SSI) with the Standardized Precipitation Index (SPI-n) for 224 stations across India to analyze drought propagation time, which is specific to each catchment. Results indicate higher propagation times for basins lying in arid and semi-arid climate regions whereas lower propagation time is found for basins lying in wetter climate regions. The run theory is applied to SSI to identify all streamflow drought events for each station and the optimal Hydrological Drought Instantaneous Development (IDS) and Instantaneous Recovery Speeds (IRS) are calculated along with parameters; duration and severity. Drought propagation speeds can be used to simulate drought duration and severity for a catchment. Simulated drought duration for various catchments shows good agreement (R2 > 0.7) with observed drought duration, therefore calculated optimal IDS and IRS can be used in forecasting drought conditions for each catchment. The effect of catchment characteristics on drought parameters was evaluated statistically by using heatmaps and bivariate correlation. This study provides comprehensive catchment-specific drought analysis for all major basins of India, which can be used by water managers to promptly and effectively avert drought and related disasters.
Innovative geo-monitoring system to assess hydro-hazards at road embankments
Authors: Michalis Panagiotis , Xu Yi , Koursari Eftychia , Wallace Stuart , Valyrakis Manousos
Published: March 2020

Road infrastructure is expected to face extreme pressure due to ageing and climatic extremes [1] as evident by recent cases of flash floods followed by drought periods. Among the most vulnerable elements of civil infrastructure are considered to be the road embankments that are not expected to withstand the prospective flood extremes. Seepage and internal erosion patterns inside the body of embankments are difficult to be assessed with conventional methods (e.g. visual inspections) and therefore go undetected leading to irreversible effects with major disruption and costs to road asset owners and maintainers. Flood-induced hazards can cause sudden collapse of bridge infrastructure without prior warning, and with significant socio-economic impacts [2]. Various sensor applications have focused on the development of monitoring systems to assess in real-time hydro and geo-hazards [2, 3, 4, 5]

This study focuses on the development and application of a real-time geo-monitoring system at a pilot road embankment in Scotland (UK) to remotely assess the evolving characteristics of hydro-hazards. The system will also provide early warning of such hazards and timely information to asset owner for proactive actions and early maintenance to avoid irreversible and costly major rehabilitation activities.

[1] Michalis, P., Konstantinidis, F. and Valyrakis, M. (2019) The road towards Civil Infrastructure 4.0 for proactive asset management of critical infrastructure systems. Proceedings of the 2nd International Conference on Natural Hazards & Infrastructure (ICONHIC2019), Chania, Greece, 23–26 June 2019, pp.1-9.

[2] Koursari, E., Wallace, S., Valyrakis, M. and Michalis, P. (2019) The need for real time and robust sensing of infrastructure risk due to extreme hydrologic events, 2019 UK/ China Emerging Technologies (UCET), Glasgow, United Kingdom, 2019, pp. 1-3. doi: 10.1109/UCET.2019.8881865

[3] Michalis, P., Saafi, M. and Judd, M. (2012) Wireless sensor networks for surveillance and monitoring of bridge scour. Proceedings of the XI International Conference Protection and Restoration of the Environment - PRE XI. Thessaloniki, Greece, pp. 1345–1354

[4] Valyrakis M. and Alexakis, A. (2016) Development of a “smart-pebble” for tracking sediment transport. International Conference on Fluvial Hydraulics River Flow 2016, St. Liouis, MO, 8p.

[5] Michalis, P., Saafi, M. and M.D. Judd. (2012) Integrated Wireless Sensing Technology for Surveillance and Monitoring of Bridge Scour. Proceedings of the 6th International Conference on Scour and Erosion, France, Paris, pp. 395-402.

Acknowledgements: This research project has been funded by Transport Scotland, under the 2019/20 Innovation Fund (Scheme ID19/SE/0401/032).
Temporal variability in soil organic carbon in response to erosion in mountain agricultural landscapes
Authors: Vasil’chuk Jessica , Gaspar Leticia , Lizaga Ivan , Navas Ana
Published: March 2020

Soil erosion leads to the loss of fertile topsoil, resulting in one of the principal soil degradation problems in agricultural landscapes worldwide. Soil redistribution processes affect the spatial and temporal variability of soil properties and nutrients, as soil organic carbon (SOC) which is linked to soil quality and soil functions. In the context of climate change mitigation as well as soil fertility and food security, there has been considerable interest in monitoring soil and carbon loss, especially in erosion-affected agricultural landscapes.

In this study, we attempt to evaluate the temporal variation of SOC and carbon fractions in a Mediterranean mountain agroecosystem. To this purpose, repeating soil sampling and carbon measurements within the same sites was undertaken in 2003 and in 2016. The sampling sites were located in agricultural areas where erosion or deposition preferably occurs based on soil redistribution rates obtained by using 137Cs measurements. The content of soil organic carbon (SOC) and the active and stable SOC fractions, (ACF and SCF, respectively) contents were measured by the dry combustion method using LECO RC-612 equipment.

Although statistically significant differences between the two surveys were not found, the mean content of SOC, ACF and SCF were slightly lower in the survey taken in 2016 than the one in 2013. Repeated topsoil sampling (0-5 cm) after 13 years reveals SOC and ACF losses for almost all the agricultural soils selected in this research. It’s important to highlight that the biggest differences between the two surveys are identified in the sites located in areas with steep slopes, while small variations occurred in the sites located in gentle slopes where deposition processes predominate. However, even if SCF losses were detected, especially in the erosive sites located in steep slopes, the content of SCF slightly increases for the second survey in sites located in depositional areas. To date, there have been few attempts to monitor soil carbon in Mediterranean soils, and this study represents a preliminary investigation that may be suitable for tracking absolute changes in SOC and carbon fractions in agricultural landscapes.
Historical Reconstruction of Anthropogenic Carbon and Excess Heat Content in the Subtropical North Atlantic Ocean
Authors: Mercier Herle , Messias Marie-Jose
Published: March 2020

The oceans have mitigated global warming by the absorption of 90% of the excess heat resulting from anthropogenic radiative forcing and of 1/3 of the anthropogenic carbon (Cant). There are still major uncertainties concerning their regional rates of uptake (or loss), transport and storage by the oceans, knowledge of which is key to the heat and carbon balances, and essential to reduce the uncertainties in global warming prediction. Here, we used tracers observations (transient and passive CFC-11, CFC-12, SF6, natural C14, the conservative PO4* and NO3*, salinity and temperature) and a maximum entropy inverse method to compute Green’s functions (G), which contain intrinsically information on ocean dynamics and transit times from the source regions. From G, we propagated surface history of temperature and Cant to reconstruct their fields in the ocean for the industrial era and to quantify their source regions. We present reconstructions of Cant and excess heat (taken as the temperature anomaly from 1850) along the 24°N trans-Atlantic section, at the crossroads of the main contributors of the AMOC and an hot spot of heat and carbon storage, from 5 repeats spanning 1992 to 2015. We show that Cant reconstructions, dominated by the strong increase of Cant in the atmosphere, compare well with a previous global historical reconstruction as well as Cant estimates in the water masses at 24°N. The excess heat reconstructions are tempered by the natural variability that can exceed the anthropogenic trend. They show a net invasion and warming of the top 800m from the 1920’s (0.01°C/y). The trend slightly weakens in the late 1970’s followed by an acceleration from the 2000’s (0.02°C/y). For the well–ventilated deeper waters of the DWBC around 1500m, after a notable cooling period, a weak warming departs in the 1950’s with a trend of 0.001°C/y up to the 2000’s and of 0.006°C/y afterwards. The waters below 2000m suggest a continuous warming from the 1930’s, with a more pronounced trend centered at 3000m of 0.001°C/y up to the 2000’s and of 0.003°C/y afterwards. This excess heat evolution in the DWBC contrasts with the Cant evolution which shows continuous increase in Cant content in the upper NADW. Our results highlight the difference of drowning up of Cant ant heat into the deeper ocean, reflecting their different surface histories in the formation regions.
New-generation OMI NO2 Standard Product: Algorithm description and initial results
Authors: Lamsal Lok , Krotkov Nickolay , Vasilkov Alexander , Marchenko Sergey , Joiner Joanna , Qin Wenhan , Yang Eun-Su , Swartz William , Choi Sungyeon , Fasnacht Zachary , Haffner David , Fisher Bradford
Published: March 2020

We present our new and improved version (version 4.0) of the NASA standard nitrogen dioxide (NO2) product from the Ozone Monitoring Instrument (OMI) on the Aura satellite. This version incorporates the most important improvements proposed for regional OMI NO2 products by expert users, and enhances NO2 data quality on a global scale through improvements in the Air Mass Factors (AMFs) in several ways. The algorithm is based on a conceptually new, geometry-dependent Lambertian surface equivalent reflectivity (GLER) operational product. GLER is calculated using the vector radiative transfer model VLIDORT, which uses as input high–resolution bidirectional reflectance distribution function (BRDF) information from NASA’s Aqua MODIS instrument over land and the wind-dependent Cox–Munk wave-facet slope distribution over water, the latter with a contribution from the water-leaving radiance. The GLER and our corresponding, consistently retrieved effective cloud fraction and O2-O2 optical centroid cloud pressures provide inputs to the new NO2 AMF algorithm, which increases tropospheric NO2 by up to 50% in highly polluted areas; the differences include both cloud and surface BRDF effects as well as biases between the MODIS and OMI-based surface reflectance data sets. We assess the new product using independent observations from ground-based and airborne instruments. The improved NO2 data record could be beneficial for studies related to emissions and trends of nitrogen oxides (NOx) and co-emitted gases.
Time to wake up to climate change and the accelerating phosphorus cycle
Authors: Haygarth Phil
Published: March 2020

We urgently need to wake up to the role that climate change will be playing in the phosphorus cycle.  The paper will attempt to address the complexities, controversies and uncertainties of estimating the effects that climate change is having on the phosphorus cycle.  Citing an example from three UK catchments, the effect of climate change on average winter phosphorus loads is predicted to increase by up to 30% by the 2050s, and these effects will only be off-set by large-scale agricultural changes (e.g. a 20–80% reduction in phosphorus inputs).  Achieving phosphorus-related quality water in diverse and productive agricultural landscapes under a changing climate is going to be a massive challenge.  It is less than a century since we started mining rock phosphate, but in the context of a 4.5-billion-year-old earth and the acceleration due to climate, we are living through a switching point for phosphorus in the earth system.
Assessing the vulnerability of shallow groundwater resources to deep subsurface energy activities (VoGERA)
Authors: Ward Rob , Beerten Koen , Zaadnoordijk Willem , Slenter Cis , Bianchi Marco , Rotár-Szalkai Ágnes , Mallin Martin Daniel
Published: March 2020

Society is increasingly looking to the subsurface for our energy needs, be that for extracting geothermal energy, shale gas, or buffering heat, gas, or storing by-products of energy production. An increasingly crowded subsurface presents risks to groundwater relied on for water supply, since subsurface activities can introduce or release contaminants and alter subsurface properties. The VoGERA project is investigating the vulnerability of shallow groundwater from a range of subsurface energy technologies across different hydrogeological and geological settings within Europe. A suite of conceptual models compares the intrinsic vulnerability for different geological (crystalline, poorly consolidated and well consolidated sedimentary basins) and hydrogeological (basin centre and margins) conditions. They also consider the impacts of different subsurface activity types broadly categorised as those processes including injection, abstraction and a neutral fluid balance. Potential contamination pathways are being investigated at four case study sites; the Rauw Fault in Belgium, Panonian Basin in Hungary, The Peel Boundary Fault in the Netherlands and the Vale of Pickering in the UK. Geophysical, hydrological and hydrochemical data from these sites will be assessed in order to improve contamination pathway process understanding in a European setting. Findings from the case study sites will be used to evaluate the conceptual models and to develop a tool for decision makers and the public to assess the vulnerability to shallow groundwater from subsurface energy activities depending on the activity, and geological and hydrogeological conditions at a specific location. The VoGERA project is funded as part of the European Union’s Horizon 2020 GeoERA network of projects under the Groundwater theme (Grant agreement number 731166).
Coroboration of magnetotelluric investigations with other geophysical anomalies for a case study located in North-West to central part of Romania
Authors: Asimopolos Natalia-Silvia , Asimopolos Laurentiu
Published: March 2020

The results of the magnetoteluric investigations carried out along the profiles are presented in the form of sections in which the variations of the different parameters, the 2-D modeling, as well as the inversions.

The results of the geophysical researches (magnetotellurics, gravity, geomagnetics) obtained were aimed at obtaining a unitary image on the deep geological structure in the investigated area. A number of information was obtained regarding such as:

Determination of the thickness of the package of formations belonging to the post-tectogenetic sedimentary cover of the Transylvanian Depression; sedimentary sedimentary cover, conductive, with a maximum thickness of approximately 4000 m in the Pannonian Depression;

Contouring of the Tethysian Major Suture (near the town of Alba Iulia in the Transylvanian Basin), represented by the Transylvanian nappes system (ofiolitic complex and sedimentary formations), with resistivities of about 500 Ohm*m, which separates two blocks with continental crust of different thicknesses (22- 27 km for Internal Dacids and 32-36 km for Median Dacids);

Highlighting the change of nappes systems belonging to the Transylvanians, with a wide development both to the north (Căpâlnas-Techereu nappes and the nappes of Groşi and Criş), as well as to the east (the ophiolite complex and sedimentary cover), over the Biharia nappes system, respectively Central-Eastern Carpathian nappes; extension of the Codru and Biharia - Arieşeni nappes, the last with higher resistivities (200 Ohm*m);

Highlighting the transcrustal fault that marks the contact between the Inner Dacides and the Median ones;

Individualization at the level of the lower crust of a transition zone; significant decrease of resistivity, as a consequence of the presence of the fluids in the transition zone, from the pressure in the pores from lithostatic type to the hydrostatic type (occurs at depths of 22 - 30 km and at temperatures of 350º - 400º C).

The electromagnetic data reflect the anomalies of electrical conductivity in a sensitive way, but due to the many causes that can generate them, a careful analysis of the particularities existing for each case, especially the superficial ones, was necessary.

The correlation of the all the information provided in sections (resistivity, phases, density, magnetic susceptibility), inversions, modeling, lead to the validation of the model.
How serpentine peridotites can leak through subduction channels
Authors: Vannucchi Paola , Morgan Jason , Polonia Alina , Molli Giancarlo
Published: March 2020

Serpentinized peridotites are weaker than other mantle rocks, with an internal friction coefficient μi~0.3 vs. ~0.6. Therefore they often promote strain localization. Serpentinite is also considerably lower in density (r=2.5-2.6 g/cm3) than most rocks. In the presence of denser material, its buoyancy can mobilize upwelling masses and aid exhumation. Serpentinized peridotites can therefore influence the evolution of tectonic plate boundaries: their presence enhances shear processes, and serpentinite-hosted faults can evolve into zones of permanent lithospheric weakness that can be reactivated during different tectonic phases. Fault reactivation also provides paths for fluid infiltration and upward remobilization of serpentinized peridotites that can also interact diapirically with overlying rocks.

We have compiled observations that document the near-surface journey of serpentinized peridotites that are exhumed during rifting and continental break-up, reactivated as buoyant material during subduction, and ultimately emplaced as ‘ophiolite-like’ fragments within orogenic belts. This lifecycle is particularly well documented in former Tethys margins that now subduct beneath the Calabrian Arc. Here recent studies describe serpentinized peridotites that diapirically rose from a subducting lithospheric slab to be emplaced into the accretionary prism in front of the continental arc. We show that this newly recognized mode of subduction-linked serpentine diapirism from the downgoing lithospheric slab is consistent with the origin of some exhumed mantle rocks in the Apennines, with these assemblages having been ultimately emplaced into their present locations during Alpine Orogenesis. Transfer of serpentinized peridotites from the mantle lithosphere of the subducting slab to the overriding plate motivates the concept of a potentially “leaky” subduction channel.  In addition to passing vertically through a shallow subduction channel, weak serpentine bodies may also rise into and preferentially migrate within the intraplate shear zone, leading to strong lateral heterogeneities in its composition, mechanical strength and seismic characteristics.