bluuebunny/crossref_metadata_2025 huggingface dataset:
Michigan International Copper Analogue (MICA) project – assessment of long-term behaviour of copper in repository relevant environments
Authors: Liebscher Axel , Reijonen Heini , Aaltonen Ismo , Liu Xuan , Lilja Christina , Norris Simon , Waffle Lindsay , Keech Peter , Diomidis Nikitas
Published: March 2022

One of the key requirements for the deep geological disposal of high-level nuclear waste is the assessment of its long-term performance and safety. As any other barrier of the disposal system, waste containers must fulfil their respective safety functions for the required duration, which can vary from a few hundreds of years to several hundreds of thousands of years, depending on disposal system requirements. Sufficient corrosion resistance under repository conditions is one key requirement for container material to provide complete waste containment. Copper is an important part of many waste packaging and disposal concepts, e.g. KBS-3 developed in Sweden and Finland and Mark II developed in Canada. Much of the data available regarding its behaviour under repository conditions comes from short-term investigations, such as laboratory experiments at different scales and under controlled conditions. Observations made from copper analogue studies provide additional information on copper behaviour during the assessment time scale and under real geological environments. By this, they can support the argumentation in the safety case.

Keweenaw native copper occurrences (Lake Superior, US) reflects more than one billion years of deposit evolution covering various geological (from bedrock to sediments and even anthropogenic mine site remnants) and geochemical environments (e.g., brines to meteoric water, anoxic vs. oxic, sulphur-free vs. sulphur-bearing). These deposits have been mined for a long time and there is a great deal of knowledge related to them as well as samples collected. However, data to be used in process based safety assessments for geological disposal is lacking and no formal review has been made from the geological disposal point of view. The current MICA Project Phase I systematically collect and review the existing literature and data on the Michigan copper analogue sites and available sampling potential. Based on the outcome, MICA Project Phase II will then study and analyse prospective sites and samples to address relevant questions regarding long-term behaviour of copper under disposal conditions. The MICA Project thus will provide a unique complementary data source to estimate processes governing behaviour of metallic copper and to support safety cases.
Determination of the optimum sampling frequency for water quality monitoring schemes
Authors: Coraggio Elisa , Han Dawei , Gronow Claire , Tryfonas Theo
Published: March 2022

Water quality monitoring is essential to understanding the complex dynamics of water ecosystems, the impact of human infrastructure on them and to ensure the safe use of water resources for drinking, recreation and transport. High frequency in-situ monitoring systems are being increasingly employed in water quality monitoring schemes due to their much finer temporal measurement scales possible and reduced cost associated with manual sampling, manpower and time needed to process results compared to traditional grab-sampling.

Modelling water quality data at higher frequency reduces uncertainty and allows for the capture of transient events, although due to potential constraints of data storage, inducement of noise, and power conservation it is worthwhile not using an excessively high sampling frequency.

This study explores the issue of frequency optimisation of water quality monitoring schemes by applying three different statistical approaches for determining the optimum sampling frequency.

The proposed approaches are tested utilising a high frequency dataset built from recording continuous physical and chemical water quality parameters (temperature, dissolved oxygen (DO), fluorescent dissolved organic matter (fDOM), turbidity and conductivity) with multiparameter sondes at 3 sites in Bristol’s Floating Harbour.

As a result, this analysis provides practical tools to understand how different sampling frequencies are representative of the water quality changes. Furthermore, it helps determine the minimum frequency required to communicate periodic fluctuations in water quality and investigate the additional benefit of recording data at a frequency higher than the minimum required.
Tree-scale carbon allocation dynamics in a mature mixed forest using long-term mass balance approach 
Authors: Rog Ido , Fox Hagar , Klein Tamir
Published: March 2022

Mixed forests are typically more productive and are faster to recover from drought compared to monospecific forests. Disentangling the contribution of each species to the overall success of the forest requires observations at the individual tree level. In this study, we measured a complete set of carbon (C) pools and fluxes at the tree-level in five tree species, two conifers and three broadleaf, co-existing in a mature evergreen mixed Mediterranean forest. Our study period included a drought year, followed by an above-average year. Across species, C sinks of 38-91 kg tree-1 year-1 were 16-32% larger than C source of 27-77 kg tree-1 year-1 in the dry year, with larger belowground C investment of the shallow-rooted species. Overall, respiration was the largest sink across species and years, accounting for 26-62% of all assimilated C, followed by growth (16%) and root exudation (19%). Non-structural carbohydrates accumulation was similar between the wet and the dry year. These detailed tree-level observations expose large interspecific differences in C allocation among fluxes and tissues and specifically in response to varying water availability. These insights become useful for forest management under ongoing change.
Hydrochemistry and presence of emerging organic pollutants in groundwater of the urban Barcelona area
Authors: Schmidlin Diego , Scheiber Laura , Teixidó Marc , Criollo Rotman , Vázquez-Suñé Enric
Published: March 2022

Groundwater is a vital resource for the development of urban areas where the problem focuses on the quantity as well on the quality, which constituted a challenge to be faced, an example of this is the case of Barcelona. Currently, Barcelona groundwater is used for irrigation of parks and gardens and street cleaning due to its poor quality as a source of drinking water, in addition, there are numerous pumping in the city to prevent flooding of underground structures (e.g. subway). Barcelona is a developed city with a high population density. Due to the socio economic, industrial activities and lifestyle of its inhabitants, as is common in urban areas, there has been a progressive deterioration on the quality of its water. Among the pollutants found in these waters, of special interest are the emerging organic contaminants (EOCs), which present a high risk to the aquatic environment and human health. The behavior, spatial distribution and processes that control them in the aquatic environment are still uncertain and most of them are unregulated.

In this work, the use of classical hydrogeochemical techniques, GIS, univariate, bivariate and multivariate statistical analysis and geostatistical techniques allow to assess, identify and locate the main physicochemical processes that control the composition of this waters considering the inorganic and organic (EOCs) parameters and the correlations between them.

isotopic analysis of the SO42- molecule, , corroborated the significant contribution of wastewater in the composition of these waters. The analysis of the EOCs showed that the highest concentration of these compounds is located towards the Besòs River. This fact indicate that this would be the main source and of greater magnitude of input of EOCs into the aquifer, while towards the urban area of Barcelona the abundance of EOCs would originate from sewage filtrations, where the input is of a lesser magnitude, this was corroborated with the factorial analysis of the EOCs. The areas with reducing conditions in general showed a higher concentration of these compounds, indicating that most of them would degrade more easily in oxidizing environments.

The processes and/or contributions identified are: water-rock interaction, water mixing, redox processes, aquifer-river interaction, sewage seepage and infiltration of urban runoff. The high heterogeneity found in the physicochemical parameters and EOCs would denote the complex hydrogeological situation of the system. the abundance of EOCs found in these waters together with the isotopic analysis, would indicate that the main source of recharge for most of this samples should be anthropogenic, mostly wastewater (sewage seepage or aquifer-river interaction).
Garnet as a useful monitor of growth and ascent rates in felsic igneous systems 
Authors: Müntener Othmar , Devoir Arnaud , Bloch Elias
Published: March 2022

Although garnet is an important accessory phase in felsic igenous rocks, its potential for timescales of magmatic processes such as mineral growth rates or ascent rates through the crust is not fully exploited. The origin of garnet in felsic igneous systems range from crystallization from (mostly) peraluminous melts to entrainment of peritectic or xenocrystic garnets originating from country rocks. We investigated garnets from mid-crustal plutonic rocks from the Ivrea-Zone (N-Italy), which contain metapelitic enclaves and composite metamorphic-magmatic xeno-phenocryst garnet. Using microtomography, high resolution EPMA mapping and detailed chemical transects by LA-ICP-MS we identified garnets with metamorphic cores and multiple igneous overgrowth rims. Using independent temperature and pressure constraints such as Zr saturation temperature from zircon-bearing nanogranitoid inclusions and phase equilibrium constraints the crystallization conditions are constrained to 780 to 820°C and ~3-4 kbars, while the garnet core still records lower crustal conditions. To quantify the duration of magmatic overgrowth, we have numerically modeled Cr, Y, REEs and Hf trace element diffusion, as well as multicomponent major divalent cation diffusion within garnet using available experimental diffusion data and Cr diffusion data retrieved from natural garnets. All modelled diffusants conform to a single temperature-time path, in which the temperatures associated with the first and second magmatic overgrowths persisted for 5.4 and 6.3 kyr respectively (Devoir et al. 2021). Rhyolite-MELTS modeling was used to explore various decompression and cooling paths of ascending rhyodacitic magmas and its effects on the density and viscosity evolution. Using a range of H2O contents and resulting different viscosities for the ascending felsic magma, garnet grain settling velocities of ca. 1 m.yr-1 were calculated using the Navier Stokes equation. To preserve lower crustal garnet core compositions, maximum time scales of melt extraction of ca. 15 kyr are calculcated. Potential implications for magma ascent rates will be discussed.

Devoir, A., Bloch, E., Müntener, O. (2021) Residence time of igneous garnet in Si-rich magmatic systems: Insights from diffusion modeling of major and trace elements. Earth and Planetary Science Letters 560, 116771
Antarctic ice-shelf basal melting in a variable resolution Earth System Model
Authors: Asay-Davis Xylar , Barthel Alice , Begeman Carolyn , Comeau Darin , Hoffman Matthew , Lin Wuyin , Petersen Mark , Price Stephen , Roberts Andrew , Veneziani Milena , Van Roekel Luke , Wolfe Jonathan
Published: March 2022

The processes that govern freshwater flux from the Antarctic Ice Sheet (AIS)—ice-shelf basal melting and iceberg calving—are generally poorly represented in current Earth System Models (ESMs). The processes governing ocean flows onto the Antarctic continental and into ice-shelf cavities can only be captured accurately at resolutions significantly higher than those in typical CMIP-class ESMs. The Energy Exascale Earth System Model (E3SM) from the US Department of Energy supports regional refinement in all components, allowing global modeling with high resolution in regions of interest. Here, we present fully coupled results from an ocean/sea-ice mesh that has high resolution (12 km) on the Antarctic continental shelf and much of the Southern Ocean and low resolution (~30 to 60 km) over the rest of the globe. E3SM includes Antarctic ice-shelf cavities with fixed geometry and calculates ice-shelf basal melt rates from the heat and freshwater fluxes computed by the ocean component. In addition, E3SM permits prescribed forcing from a climatology of iceberg melt, providing a more realistic representation of these freshwater fluxes than found in many ESMs. With these new capabilities, E3SM version 2 produces realistic and stable ice-shelf basal melt rates across the continent. We show preliminary results of modeled ice-shelf basal melt rates across a range of Antarctic ice-shelves under pre-industrial and historical climate forcing, as well as the impacts of these added capabilities on the region’s climate. We show that the use of a mesoscale eddy parameterization, tapered with the mesh resolution, reduces biases even in the 12-km region where some eddies are resolved.  The accurate representation of these processes within a coupled ESM is an important step towards reducing uncertainties in projections of the Antarctic response to climate change and Antarctica's contribution to global sea-level rise.
Experimental study of wave-turbulence interaction
Authors: Smeltzer Benjamin K. , Hearst R. Jason , Ellingsen Simen Å.
Published: March 2022

Turbulence is ubiquitous in the uppermost layer of the ocean, where it interacts with surface waves. Theoretical, numerical, and experimental works (e.g. [1,2,3] respectively) predict that motion of non-breaking waves will increase turbulent energy, in turn leading to a dissipation of waves. Waves are believed to contribute significantly to the turbulence in the ocean mixed layer, yet additional measurements are needed to validate and distinguish between models and theories [4].

In this work we study the modification of turbulence by surface waves using experimental measurements of turbulent flows in the presence of waves. The measurements were performed in the water channel laboratory at NTNU Trondheim [5], able to mimic the water-side flow in the ocean surface layer under a range of conditions. An active grid at the inlet allowed the turbulence intensity and length scale to be varied while maintaining an approximately constant mean flow. The flow field was measured in the spanwise-vertical plane by stereo particle image velocimetry for various background turbulence cases with waves propagating against the current. The turbulence characteristics are compared to cases without waves, and the turbulence level is found to be increased after the passage of wave groups. The results are discussed considering predictions from rapid distortion theory [1].

 

[1] Teixeira M. and Belcher S. 2002 “On the distortion of turbulence by a progressive surface wave” J. Fluid Mechanics 458 229-267.

[2] McWilliams J. C., Sullivan P. P. and Moeng C-H. 1997 “Langmuir turbulence in the ocean” J. Fluid Mechanics 334 1-30.

[3] Thais L. and Magnaudet J. 1996 “Turbulent structure beneath surface gravity waves sheared by the wind” J. Fluid Mechanics 328 313-344.

[4] D’Asaro E.A. 2014 “Turbulence in the upper-ocean mixed layer” Annual Review of Marine Sciences 6 101-115.

[5] Jooss Y., et al. 2021 “Spatial development of a turbulent boundary layer subjected to freestream turbulence” Journal of Fluid Mechanics 911 A4.
Insights from the work of the International Association of Geomagnetism and Aeronomy (IAGA) Social Media Working Group
Authors: Rogers Hannah , Sharan Shivangi , Di Chiara Anita , Kamenikova Tereza , Leichter Barbara , Pinheiro Katia , Sanaka Sarasija
Published: March 2022

The International Association of Geomagnetism and Aeronomy (IAGA) is one of the associations under the International Union of Geodesy and Geophysics and acts as a non-governmental body to serve scientists and decision-makers in research establishments, government agencies, intergovernmental bodies, and private enterprise. IAGA promotes the work of Earth and space scientists studying the magnetic and electrical properties of the Earth, other planets, the Sun and their phenomena, and interplanetary bodies. IAGA encourages free exchange of scientific information, facilitates international collaboration in research, and is committed to supporting education and outreach.

Since December 2019, IAGA has had a dedicated social media group (under the Interdivisional Commission on Education and Outreach - ICEO) to promote the work of the organisation and encourage the building of an online community. The IAGA social media platforms now include Twitter, Instagram, Facebook, LinkedIn, YouTube, and a blog. With half the world’s population always online, it has become imperative to shift research to a virtual platform and adapt so the general public can access information about science in new ways. IAGA’s social media platforms started as an alternative version of mailing lists but have expanded into creating original posts, such as interviews with IAGA members. The IAGA Social Media working group was formally formed in January 2021 with the main aims to provide an easily accessible platform for news and an online community for IAGA members; to increase awareness of the varied work of IAGA, both within the community (to support cross-disciplinary research) and to the general public; and to promote the work of early career researchers and under-represented groups in IAGA 

In the time of a global pandemic, this working group is forging international connections, advertising opportunities, sharing news, and continuing to grow. The working group wish to share scientific successes of IAGA members and promote their work to the scientific community and broader audience. We hope to inspire young adults to be involved in the STEM (Science, Technology, Engineering & Maths) community. In this work, we provide some analytics of our social media accounts and examples of techniques that have worked well.
Learning ENSO-related Principal Modes of Vegetation via a Granger-Causal Variational Autoencoder
Authors: Varando Gherardo , Fernández-Torres Miguel-Ángel , Camps-Valls Gustau
Published: March 2022

Tackling climate change needs to understand the complex phenomena occurring on the Planet. Discovering  teleconnection patterns is an essential part of the endeavor. Events like El Niño Southern Oscillation (ENSO) impact essential climate variables at large distances, and influence the underlying Earth system dynamics. However, their automatic identification from the wealth of observational data is still unresolved. Nonlinearities, nonstationarities and the (ab)use of correlation analyses hamper the discovery of true causal patterns.  Classical approaches proceed by first, extracting principal modes of variability and second, by performing lag-correlations or Granger causal analysis to identify possible teleconnections. While the principal modes are an effective representation of the data, they could be causally not meaningful. 
To address this, we here introduce a deep learning methodology that extracts nonlinear latent representations from spatio-temporal Earth data that are Granger causal with the index altogether. The proposed algorithm consists of a variational autoencoder trained with an additional causal penalization that enforces the latent representation to be (partially) Granger-causally related to the considered signal. The causal loss term is obtained by training two additional autoregressive models to forecast some of the latent signals, one of them including the target signal as predictor. The causal penalization is finally computed by comparing the log variances of the two autoregressive models, similarly to the standard Granger causality approach. 

The major drawback of deep autoencoders with respect to the classical linear principal component approaches is the lack of a straightforward interpretability of the representations learned. 
To address this point we perform synthetic interventions in the latent space and analyse the differences in the recovered NDVI signal.
We illustrate the feasibility of the approach described to study the impact of ENSO on vegetation, which allows for a more rigorous study of impacts on ecosystems globally. The output maps show NDVI patterns which are consistent with the known phenomena induced by El Niño event. 
Reprocessing of LUH GRACE solutions – current status
Authors: Koch Igor , Duwe Mathias , Flury Jakob
Published: March 2022

Currently a reprocessing of the LUH GRACE monthly gravity field solutions is carried out at our institute. The new processing chain utilizes updated background models, parametrization and outlier detection. This processing chain is consistent with the approach currently applied for our operational GRACE-FO time series. In this contribution, we present our gravity field recovery strategy. The reprocessed time series is compared to the previous LUH GRACE series as well as to the most recent series of other GRACE analysis centers. We present a comparison of the noise behavior (in terms of residual signal over the oceans), signal content (river basin amplitudes, regional mass trends) and low degree coefficients. In addition, post-fit range-rate residuals are inspected.
Expanding the use of Copernicus marine satellite data: EUMETSAT’s user support and training activities.
Authors: Loveday Benjamin , Träger-Chatterjee Christine , Wannop Sally , Evers-King Hayley , Brando Vittorio , Rosmorduc Vinca , Ruescas Ana , Troupin Charles
Published: March 2022

Following the successes of the first phase of the European Commission Copernicus programme, EUMETSAT is continuing and expanding its offer of data access services, marine data products, as well as marine training activities and user support services, under phase two. 

EUMETSAT operates the Sentinel-3, Sentinel-6 and Jason-3 satellites, and provides level-1 and level-2 marine data products for ocean colour, sea surface temperature, and altimetry science and applications.  

User support services include data access, customisation, and visualisation platforms, web-based technical information about products, as well as a helpdesk available to answer a full range of user queries on the products and their use. 

Interactive training activities are designed to accommodate a diverse range of audiences, both research and operational, putting trainee needs and interests at the centre of learning objectives. A focus on co-development of resources and participant-led learning interventions allows participants to tailor their own experiences towards development of the skills and knowledge that will help them in their own applications and work tasks. Building on four years of successful general courses, EUMETSAT now seeks to develop further specialised training and advanced courses for the marine community.  

This presentation will showcase existing services and resources, and provide information on planned training events for 2022 and beyond. It will expand on our training approaches and provide further information on opportunities for collaboration with the wider marine community, during the UN ocean decade. 
Detecting ecosystem-relevant crossings of thresholds
Authors: Fröb Friederike , Bourgeois Timothée , Goris Nadine , Schwinger Jörg , Heinze Christoph
Published: March 2022

With ongoing climate change, multiple stressors including ocean warming, deoxygenation, ocean acidification and limited nutrient availability are expected to lead to considerable regime shifts within marine ecosystems [1]. However, distinguishing such abrupt shifts from long-term trends in physical and biogeochemical ocean variables may not only be obscured by the natural variability of the system, but also the complexity of the ecosystem itself. Moreover, species-dependent physiological tolerances are likely going to limit the detectability of crossing of thresholds or tipping points of the whole ecosystem. The metabolic index describes temperature-dependent hypoxic tolerances with respect to the oxygen supply [2]. Critical values of the metabolic index indicate the geographical limits of marine species, therefore it is a useful metric to describe the extent of a potential habitat. Here, we assess the spatio-temporal detectability of abrupt changes in such a potential habitat for selected marine species using an environmental time series changepoint detection routine developed by [3]. We compare the number and timing of these abrupt changes in different Shared Socioeconomic Pathways (SSPs) run with the fully coupled Norwegian Earth System Model version 2 (NorESM2), i.e., analysing the SSP1-26, SSP-5-34-OS, and SSP5-85 scenarios. Preliminary results reveal global, regional and local abrupt changes of lost metabolically viable potential habitat in relation to environmental stressors under different evolving climates.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 820989 (project COMFORT). The work reflects only the authors’ view; the European Commission and their executive agency are not responsible for any use that may be made of the information the work contains.

 

[1] Heinze et al., 2020, The quiet crossing of tipping points, PNAS, 118(9)

[2] Deutsch et al., 2020, Metabolic trait diversity shapes marine biogeography, Nature, 585, 557-562

[3] Beaulieu and Killick, 2018, Distinguishing trends and shifts from memory in climate data, Journal of Climate, 31(23), 9519-9543
Crustal structure and along-strike variations in the Gulf of Mexico conjugate margins: From early rifting to oceanic spreading
Authors: Izquierdo-Llavall Esther , Ringenbach Jean Claude , Sapin François , Rives Thierry , Callot Jean-Paul , Nielsen Charlotte
Published: March 2022

The Gulf of Mexico opened as a Late Triassic-Mid Jurassic continental rift that was first largely covered by the Mid-Jurassic Louann Salt and later split apart by a triangular-shaped oceanic crust. Salt in the Gulf of Mexico largely hampers the imaging and interpretation of underlying pre-salt and crustal geometries, which are fundamental for assessing the early kinematic evolution of the margin. To better define these deep geometries and their lateral variations, we built three seismic-based crustal-scale cross-sections across the Florida-Yucatan conjugate margins, in the areas where the Mid-Jurassic salt unit is thinner.

Seismic-based cross-sections image the architecture of rifting and the geometries of the continental and oceanic crusts and the transition between them (ocean-continent transition, OCT). They show a meaningful along-strike variation: the South Florida-East Yucatan area is characterized by a narrower rifted continental crust that evolves sharply to oceanic crust whereas in the North Florida and central-western Yucatan areas, the rifted continental crust is wider and the transition to the oceanic crust corresponds to a narrow magmatic or exhumed mantle domain. In the rifted continental crust, seismic profiles image doubly-verging basement faults organized into decoupled and coupled rift domains. The geometrical and cross-cutting relationships between these basement faults, the Louann Salt and the underlying pre-salt sequence indicates a progressive migration of rifting from proximal to distal domains and from the central and north-eastern to the south-eastern Gulf of Mexico.  

Bulk continental crust extension was determined using the area balancing method. Estimated horizontal extension values vary from a minimum of ∼120 km in the South Florida-East Yucatan conjugate to a minimum of ∼240 km in the North Florida-Central Yucatan conjugate, being systematically larger in the northern margin. Crustal domains identified in the cross-sections were laterally correlated and westwards extended considering gravity and magnetic anomalies data to build a regional-scale, crustal domains map of the Gulf of Mexico. This map, together with the crustal extension estimates, has been used as the reference to carry out a plate-scale reconstruction of the Gulf of Mexico from the early rifting stages to the end of oceanic spreading.

Based on our observations and considering previous models, we propose that the study area evolved from an early rift involving magmatism, to a magma-poor margin, with continental break-up (OCT formation) being characterized by mantle exhumation and associated magmatism along the North Florida and central-western Yucatan areas.
Apatite in the Upper Zone of the Bushveld (Western Limb)- evidence for a rejuvenated magma at the height of Layer 21?
Authors: Roberts Richard James , Britt Tawnee , Hetherington Callum
Published: March 2022

The occurrence of apatite and its trace element geochemistry in a borehole core through the Upper Zone from the Western Limb of the Bushveld is reported here (BK1). Apatite displays cyclic behaviour in the upper portion of the Upper Zone, appearing and disappearing several times. Two “spikes” of apatite, where apatite appears in abundance and then disappears suddenly, occur below the magnetitite layer noted as Layer 21, and are marked by a pronounced negative Eu anomaly in the apatite REE profile. The apatite intervals above Layer 21 are marked by sudden appearance and gradual disappearance, and have no Eu anomaly. Previous studies on the UZ in the Eastern Limb have noted this difference in REE profiles and have explained it either as a consequence of the trapped liquid shift, or as an indication of massive liquid immiscibility in the chamber at the level of Layer 21. We propose an alternative solution, in which a rejuvenated magma is injected into the magma chamber at or just below the level of Layer 21. This new rejuvenated magma is likely genetically related to the previous magma but is much higher in Fe and depleted in V compared to the previous magma, and is responsible for the formation of Layer 21 (8m thick), a layer considerably thicker than any other magnetitite layer, including the Main Magnetite Layer. The influx of a new magma is clear in the largest compositional shifts in the Upper Zone across layer 21, shown in the compositions of orthopyroxene (Mg#=25 below; Mg#=49 above), plagioclase (An#=47 below; #An=58 above), and olivine (Mg#=20 below; Mg#=40 below), as well as in the occurrence of liquid immiscibility only in the magma above Layer 21. In this model, the Eu anomaly created by plagioclase fractionation in the apatite below Layer 21 has been diluted by the addition of new magma which has not experienced prolonged fractionation of plagioclase.
Geodetic modelling of a multi-source deformation pattern retrieved through Sentinel-1 DInSAR measurements: the 11-15 August 2019 Piton de la Fournaise (La Réunion Island) eruption case-study
Authors: Valerio Emanuela , De Luca Claudio , Manzo Mariarosaria , Lanari Riccardo , Battaglia Maurizio
Published: March 2022

The Piton de la Fournaise volcano is located on the southeastern part of La Réunion Island and is inserted in the tectonic framework of the Indian Ocean. It is one of the most active worldwide volcanoes and it can be classified as a hot-spot basaltic one.

In this work, we focus on the eruption occurred from 11 to 15 August 2019 on the southern-southeastern flank of this volcano, inside the Enclos Fouqué caldera. In particular, this distal event was characterized by the opening of two eruptive fissures and accompanied by shallow volcano-tectonic earthquakes.

Firstly, we investigate the surface deformations induced by the occurred eruptive activity, by exploiting Differential Synthetic Aperture Radar Interferometry (DInSAR) measurements; they are obtained by processing the data collected by the Sentinel-1 satellite of the Copernicus European Program along ascending and descending orbits. Due to the position of the island in the southern hemisphere, the processed S1 interferograms are characterized by a 12-days temporal baseline; for this reason, they measure the ground deformations generated during both the pre- and co-eruptive phases. Then, we analyze the distribution of the relocated hypocenters to recognize the activated structures and to furnish further constraints to our model. Finally, we perform an analytical modelling to the computed coseismic DInSAR displacements, with the aim of investigating the volcanic source/s responsible for the measured surface deformation field.

The retrieved results reveal that several volcanic sources (one sill and four dikes, in particular) have been active during the pre- and the co-eruptive phases, allowing the magma transport towards the surface; their action can justify the complexity of the observed deformation pattern. Our findings are in good agreement with the seismicity recorded by the Observatoire Volcanologique du Piton de la Fournaise network and with several geophysical evidences, such as the comparison between the volume of the retrieved sources and the erupted magma volumes, and the fissures location.
Extreme droughts and floods in the Amazon forest
Authors: Koren Gerbrand , Botía Santiago , Domingues Lucas G. , Florentie Liesbeth , Gatti Luciana V. , Gloor Manuel , Harrigan Shaun , Krol Maarten C. , Luijkx Ingrid T. , Miller John B. , Naus Stijn , Peters Wouter
Published: March 2022

In recent years, the Amazon forest has experienced several major droughts (2010, 2015/16) and floods (2012, 2014, 2021). Extreme events represent a threat to the Amazons important functions, but these perturbations also provide valuable insights into the underlying mechanisms. Here we studied the most recent massive drought and flood events in detail, and quantified their severity and spatiotemporal extent relative to a multi-year baseline.

First, we describe the anomalous hydrological status of these events, by bringing together a large variety of data sets, including in-situ observations and reanalysis products for precipitation, discharge, vapor pressure deficit and soil moisture. During the strong El Niño conditions following the dry season of 2015, the precipitation fell below its climatological values. This was soon reflected in low discharge rates and soil moisture levels, persisting far into the year 2016 for some regions. In contrast, we find anomalously high precipitation over the northern Amazon during the first months of 2021, resulting in high discharge rates,  and  rising river levels that have led to massive floods in downstream regions.

Finally, we quantified the impact of the 2015/16 drought on vegetation using the inverse model CarbonTacker South America (CT-SAM) and remote sensing proxies for photosynthesis. To address the uncertainty in prior emission estimates, we have used a range of different biosphere models (SiBCASA, SiB4), including a biosphere model linked to a detailed hydrological model (PCR-GLOBWB). For the fire flux we used multiple data sets (GFAS, SiBCASA-GFED4), including a modified version based on CO inversions performed with the TM5-4DVAR system. We find that photosynthesis was reduced during the 2015 drought, especially in the drier, southern part of the Amazon. This was followed by a recovery in the first months of 2016, but during the subsequent dry season a secondary impact on photosynthesis was found. The inversely derived net CO2 fluxes do not have the same high resolution as the satellite products, but when assessed over larger scales, a consistent drought signal is derived.
On the influence of Ocean Mixed Layer and Sea Surface Temperature Anomaly in the genesis and evolution of the Mediterranean Tropical-Like cyclones “IANOS”.
Authors: Ricchi Antonio , Liguori Giovanni , Cavicchia Leone , Miglietta Mario Marcello , Bonaldo Davide , Carniel Sandro , Ferretti Rossella
Published: March 2022

Over the Mediterranean basin we can occasionally observe intense cyclones showing tropical characteristics and known as Mediterranean Tropical-Like Cyclones (TLC) or Medicanes (short for “Mediterranean Hurricanes”). Previous studies focusing on past TLCs events have found that SST anomalies play a fundamental role in modulating the intense air-sea exchange of latent and sensible heat fluxes, hence controlling both development and evolution of TLCs. However, given the connection between ocean mixed layer, ocean heat content and temperature, it is important to explore also the role of the mixed layer depth (MLD). In this study we investigated the role of both SST and MLD on genesis and evolution of a recent record-breaking TLC. Specifically, we focus on TCL “IANOS”, a cyclone that originated over the southern Ionian Sea around 14 Sept 2020, moved over the Central Ionian Sea from south-west to North-East, and made landfall around 19 Sept 2020 over Greece mainland coast. It developed over a basin where a positive SST anomaly up to 4 °C was detected, which coincided with the sea area where it reached the maximum intensity. We conducted a series of experiments using an atmospheric model (WRF - Weather Research and Forecasting system) driven by underlying SST (standalone configuration) with daily update or coupled to a simple mixed-layer ocean model (SLAB ocean), with SST calculated at every time step using the SLAB ocean for a given value of the MLD. WRF was implemented with 3 km grid spacing, forced with GFS-GDAL analysis (0.25°x0.25° horizontal resolution), while SST or MLD initialization, for standalone or coupled runs, respectively, are provided by the MFS-CMEMs Copernicus dataset at 4 km of horizontal resolution. For the studied TLC, the mean MLD is modified by increasing or decreasing its depth by 10 m, 30 m, 50 m; the preliminary results show that the MLD influences not only the intensity of the cyclone but also the structure of the precipitation field both in terms of magnitude and location. At first  the MLD thickness was characterized  for the days in which the cyclone developed using ocean modeling data. Then we identified possible past and future climatological scenarios of MLD thickness. Starting from these data, we simulated the impact of the MLD, and consequently of the Ocean Heat Content, on the TLC. The preliminary results show that the MLD influences not only the intensity of the cyclone but also the structure of the precipitation field both in terms of magnitude and location. The results deserve further investigation in particular in the context of climate change scenarios.
Slope stability analysis of embankment dam under total and effective pore pressure
Authors: Hartanto Tri
Published: March 2022

Very often many new construction and operating embankment dams need to be evaluated in terms of the slope stability. The necessity of considering body forces, pore-water pressures, and a variety of soil types in the analysis vitiates the application of methods that are well founded in the mechanics of continua and employ representative constitutive equations.

This study comparing stability analysis using total stress after the end of construction with effective stress couple of years later after the first impounding. Studies have indicated the advantages to be obtained employing an effective stress failure criterion (Bishop, 1952, Henkel and Skempton, 1955 and Bishop, 1960) for analysis and design of embankment dams. Pore-water pressure are determined from piezometer readings during the construction until the dam was operated.

This paper presents the results of stability analysis of embankments dam with both parameters and conditions, resulting that pore water pressures influence slope stability of the embankment.
Changes of air quality and its associated health and economic burden in 31 provincial capital cities in China during COVID-19 pandemic
Authors: Ge Xinlei , Nie Dongyang
Published: March 2022

With outbreak of the novel coronavirus disease (COVID-19), immediate prevention and control actions were imposed in China. Here, we conducted a timely investigation on the changes of air quality, associated health burden and economic loss during the COVID-19 pandemic (January 1 to May 2, 2020). We found an overall improvement of air quality by analyzing data from 31 provincial cities, due to varying degrees of NO2, PM2.5, PM10 and CO reductions outweighing the significant O3 increase. Such improvement corresponds to a total avoided premature mortality of 9410 (7273–11,144) in the 31 cities by comparing the health burdens between 2019 and 2020. NO2 reduction was the largest contributor (55%) to this health benefit, far exceeding PM2.5 (10.9%) and PM10 (23.9%). O3 instead was the only negative factor among six pollutants. The period with the largest daily avoided deaths was rather not the period with strict lockdown but that during February 25 to March 31, due to largest reduction of NO2 and smallest increase of O3. Southwest, Central and East China were regions with relatively high daily avoided deaths, while for some cities in Northeast China, the air pollution was even worse, therefore could cause more deaths than 2019. Correspondingly, the avoided health economic loss attributable to air quality improvement was 19.4 (15.0–23.0) billion. Its distribution was generally similar to results of health burden, except that due to regional differences in willingness to pay to reduce risks of premature deaths, East China became the region with largest daily avoided economic loss. Our results here quantitatively assess the effects of short-term control measures on changes of air quality as well as its associated health and economic burden, and such information is beneficial to future air pollution control.
Gauging the ungauged: Estimating rainfall in urbanized river basins using ground-based and spaceborne sensors
Authors: Bogerd Linda , Pinto Rose Boahemaa , van Emmerik Tim , Uijlenhoet Remko
Published: March 2022

Accurate rainfall estimates in urban areas are vital for water management, pollution transport, and flood forecasts. To cover the high spatial (and temporal) variability of rainfall, uniformly distributed observation networks are required.

In many urban areas dedicated rainfall observations are limited because of low available budgets or unsuitable technology. Therefore, this study compared and assessed the accuracy of three “non-traditional” rainfall datasets in the Odaw (Accra, Ghana) river basin to help future modellers to decide which dataset is the best fit, for instance to predict floods. The Odaw river basin is one of the main drainage systems in Accra with a total catchment area of about 270 km2. Over the past three decades, the Odaw basin has been challenged with floods, but due to the lack of a good representation of rainfall measurements, the ability to accurately simulate or forecast floods in the basin is limited.

Two rainfall datasets are derived from satellite observations and one from crowdsourced rain gauges. The three estimates were all available for the study period (2020) and were analysed and compared at a thirty-minute time-interval. The first space-based product is the most recent version (V06B) of IMERG, the gridded multisatellite precipitation product of the Global Precipitation Measurement (GPM) mission; the second space-based product is the MSG-SEVIRI infrared satellite imagery, an innovative rainfall dataset based on geostationary data available day and night. The ground-based data was retrieved from ten TAHMO rain gauges. Because the satellite products consists of pixels while the TAHMO observations are point measurements, the stations were assigned to the pixels of the satellite products.

Results show that all three rainfall datasets revealed a systematic spatial variation, with on average more rainfall observed upstream than downstream. Although all datasets reproduced a similar annual accumulation, the rainfall intensity observed by the TAHMO stations (point measurements) were much higher, sometimes even more than twice as high. Days with high rainfall amounts (when the daily average TAHMO rain rate exceeded 15 mm/hr) were used as case studies, as these days were hypothesised to be related to flooding. During these days space-borne radar overpasses were used to get some impression about the spatial characteristics of the rainfall events. With this presentation we aim to demonstrate the applicability of freely available data to estimate rainfall at various temporal and spatial scales in (formerly) ungauged urbanized river basins.
The 2021 unrest at Vulcano: insights from ground-based and satellites observations
Authors: Diliberto Iole Serena , Pailot Bonnètat Sophie , Harris Andrew J.L. , Bani Philipson , Rafflin Victoria , Boudoire Guillame , Gattuso Alessandro , Grassa Fausto , Van Wyk de Vries Benjamin , Bilotta Giuseppe , Cappello Annalisa , Ganci Gaetana
Published: March 2022

By 2021, Vulcano, Aeolian Islands (Italy), experienced a dramatic increase in different monitoring parameters, including microseismicity, ground deformation, fumarole temperatures, and volatile emissions of steam, carbon, and sulfur dioxide. The volcanic unrest was noticeable in September 2021, causing the Civil Protection to raise the alert level from green to yellow on October 1st. Here we present a number of ground- and satellite-based thermal methodologies used to detect and characterize the change of state of the La Fossa hydrothermal system between January 2021 and January 2022. We analyzed: (i) the temperature and (ii) CO2 flux data acquired at 15 cm‐depth on a N-S profile N-S and grid in the geothermally heated area during three field surveys in June, September 2021 and January 2022; (iii) a time series acquired with a radiometer including temperatures and number of vents inside the fumarole field from 1994 to 2022; (v) thermal images acquired by a hand-held thermal camera during four field surveys in March, June and September 2021, plus January 2022; (v) nighttime multi-spectral satellite images acquired by ASTER, ECOSTRESS and VIIRS sensors from January 2021 to January 2022. Satellite images show a clear increase in the radiant heat flux/land surface temperature as well as in the number of thermally anomalous pixels, this thermal anomaly has been observed from mid-September. However, by combining ground and satellite techniques the starting point of this change can be tracked thermally from at least June 2021. Our experience suggests that the methods, essentially based on the thermal monitoring, could be used to herald upcoming crises. This method has been applied on a close conduit volcano and highlighted changes of trend in the solfataric release. Further tests, aiming to reduce (filter or define) the external effects on the land surface temperature, and to define the correlations with the long term monitoring data (either ground-based or by remote sensing) in this area, would assess a standardized methodology to monitoring the subtle, but diffuse fluid release. The assessed methodology could then be applied to other active hydrothermal systems, to herald thermal changes on the surface, related to the increasing energy released from a deep source.