bluuebunny/crossref_metadata_2025 huggingface dataset:
Copper(II) removal by natural siderite (FeCO3) from surface and groundwaters
Authors: Füllenbach Lisa C. , Perez Jeffrey Paolo H. , Freeman Helen M. , Thomas Andrew N. , Benning Liane G. , Oelkers Eric H.
Published: March 2020

Anthropological use of land and resources releases vast amounts of waste into surface waters and aquifers. Copper(II) is one of the most widely occurring heavy metal contaminants, introduced into the environment from industrial discharge, landfill leakage, agricultural and mining sources. Common remediation strategies for redox-sensitive Cu(II) are based on adsorption or phytoremediation methods. To experimentally test the efficiency of Cu(II) retention by inorganic redox reaction processes suitable for in situ surface- and groundwater remediation applications, we used siderite (FeCO3), which is abundant in anoxic sediments and soils and as a carbonate highly soluble in acidic environments. Its dissolution increases alkalinity and releases highly reactive, redox sensitive Fe(II). This aqueous ferrous iron can act as 1) a precursor for Fe(III) (hydr)oxides in oxic conditions, which are effective sorbents of heavy metals, and 2) a reducing agent under reducing conditions, where it can form a strong redox couple with Cu(II). We investigated the long term (1008 h) removal of aqueous Cu(II) through siderite dissolution batch experiments under oxic and anoxic conditions and monitored changes in the aqueous concentrations of Cu and Fe, pH and the reacted solids morphology over time. Cu adsorption and speciation on the reaction products was determined by X-ray absorption and photoelectron spectroscopies.

Under oxic conditions, increasing alkalinity led to a rapid increase in solution pH and the precipitation of nanoparticulate goethite and hematite from the released ferrous iron. After 1008 h of reaction, 80 % of the dissolved Cu(II) were removed from solution by sorption, whereby up to >30 % of this sorbed Cu(II) was reduced to Cu(I). Under anoxic conditions, the solution pH increased abruptly and copper uptake occurred more than twice as fast as under oxic conditions. Notably, the released Fe(II) was oxidized by Cu(II) leading to the precipitation of lepidocrocite, while all copper was removed from solution with >70 % of Cu(II) being reduced to Cu(0).

Our results suggest that 1) redox reactions between aqueous Cu(II) and Fe(II) promote coupled dissolution-precipitation and adsorption mechanisms responsible for Cu(II) removal, and that 2) siderite is a low-cost and effective material that is potentially useful for in situ remediation in either oxygenated or reduced environments.
The Role of Soil Properties on Regional Climate Simulations
Authors: Berbery E. Hugo , Dennis Eli
Published: March 2020

The land surface is inextricably linked to the atmospheric circulation as it dictates the location and strength of land surface-atmosphere (LA) coupling mechanisms. In this context, soil hydraulic properties are critical to estimate sub-surface processes and fluxes at the surface.  In most numerical weather and climate models, those properties are assigned through maps of soil texture complemented with look-up tables.  Then, the hydraulic properties are used in a large variety of process parameterizations within the models.  In this study, we investigate the sensitivity of the simulated regional climate to changes in the prescribed soil maps in the WRF/CLM4 modeling suite.  Comparison of two widely used soil texture databases, the USGS State Soil Geographic Database (STATSGO) and Beijing Normal University’s soil texture database (GSDE), over the United States and Central America reveals that only 32% of soil texture classifications are in common. Further, the differences are not random but tend to depict small-to-large spatial patterns with a preponderance of either finer or coarser grains. Over North America, the US Great Plains have finer grains in GSDE than in STATSGO, while the opposite is true over Central Mexico.

 

Seasonal simulations were carried out to assess the changes in the soil-water system that result from changing the soil types (GSDE vs. STATSGO) and their corresponding hydraulic properties. Wherever GSDE has finer grains than STATSGO (e.g., over the US Great Plains), the soil will retain water more strongly as evidenced by smaller latent heat fluxes and larger sensible heat flux. On the other hand, areas of coarser grains in GSDE (e.g., over central Mexico) exhibit an increase in latent heat fluxes and a corresponding decrease in sensible heat flux. Regions with an increase/decrease in latent heat flux have a corresponding increase/decrease in the 2-m moisture content. Similar relations are obtained between sensible heat flux and 2-m temperature. These changes also affect the atmospheric column, which responds with an increase/decrease of temperature and height of the planetary boundary layer. Changes in the vertical structure induce changes in the vertical instability and winds. Interestingly, the chain of modifications resulting from soil texture changes impact the moisture fluxes, and more generally, the atmospheric water budget.
Unravelling controls on methane uptake in a temperate forest soil: impacts of ectomycorrhizas
Authors: Toet Sylvia , Ma Ruochan , Morton Phoebe , Ineson Phil
Published: March 2020

Methane (CH4) is an important greenhouse gas, globally responsible for 17% of current radiative forcing. Soils can be important net sources or sinks of CH4 depending on the net balance of two contrasting microbial processes - CH4 production and CH4 oxidation. In unsaturated soils, the aerobic methane oxidation process often dominates. These soils form the only global terrestrial CH4 sink, but estimates are still highly uncertain, both spatially and temporally. Forest soils have shown some of the strongest net CH4 uptake rates, but this is not consistent across sites and the controls are poorly understood.

In this field study, we focused on the effects of ectomycorrhizas on net CH4 uptake in an unsaturated, sandy gley podzolic soil of a mature coniferous forest stand dominated by Lodgepole pine (Pinus contorta) in Northern England over three years. Methane fluxes were determined in cores with soil only (roots and ectomycorrhizal mycelium excluded using windows with 1 µm mesh in the cores) and cores with soil and ectomycorrhizal mycelium (only roots excluded with 41 µm mesh). Net CH4 uptake rates in summer were higher when ectomycorrhizal mycelium was present, whereas the opposite was observed in winter. We will discuss mechanisms that may underpin these ectomycorrhizal impacts on net CH4 uptake in unsaturated forest soils.
Coupling Hydrological models using BMI in eWaterCycle
Authors: Drost Niels , Hut Rolf , Van De Giesen Nick , van Werkhoven Ben , Aerts Jerom P.M. , Camphuijsen Jaro , Pelupessy Inti , Weel Berend , Verhoeven Stefan , van Haren Ronald , Hutton Eric , Alidoost Fakhereh , van den Oord Gijs , Dzigan Yifat , Andela Bouwe , Kalverla Peter ,   Model Contributors
Published: March 2020

The eWaterCycle platform is a fully Open-Source platform built specifically to advance the state of FAIR and Open Science in hydrological Modeling. eWaterCycle builds on web technology, notebooks and containers to offer an integrated modeling experimentation environment for scientists. It allows scientists to run any supported hydrological model with ease, including setup and pre-processing of all data required. Common datasets such as ERA-Interim and ERA-5 forcing data and observations for verification of model output quality are available for usage by the models, and a Jupyter based interface is available for ease of use.

As the main API for models, we use the Basic Model Interface (BMI). This allows us to support models in a multitude of languages. Our gRPC based system allows coupling of models, and running of multiple instances of the same model. Our system was designed to work with higher level interfaces such as PyMT, and we are currently integrating PyMT into our platform. During my talk I will give an overview of the different elements of the eWaterCycle platform.

The BMI interface was specifically designed to make it easy to implement in any given model. During the FAIR Hydrological Modeling workshop a number of modelers worked on creating a BMI interface for their models, and making them available in the eWaterCycle system. To show the amount of effort required in common cases, I will show the BMI interface that was created for a number of these models, including SUMMA, HYPE, Marrmot, TopoFlex, LisFlood, WFLOW, and PCR-GLOBWB.
Using spherical scaling functions in scalar and vector airborne gravimetry
Authors: Vyazmin Vadim , Bolotin Yuri
Published: March 2020

Airborne gravimetry is capable to provide Earth’s gravity data of high accuracy and spatial resolution for any area of interest, in particular for hard-to-reach areas. An airborne gravimetry measuring system consists of a stable-platform or strapdown gravimeter, and GNSS receivers. In traditional (scalar) airborne gravimetry, the vertical component of the gravity disturbance vector is measured. In actively developing vector gravimetry, all three components of the gravity disturbance vector are measured.

In this research, we aim at developing new postprocessing algorithms for estimating gravity from airborne data taking into account a priori information about spatial behavior of the gravity field in the survey area. We propose two algorithms for solving the following two problems:

1) In scalar gravimetry:  Mapping gravity at the flight height using the gravity disturbances estimated along the flight lines (via low-pass or Kalman filtering), taking into account spatial correlation of the gravity field in the survey area and statistical information on the along-line gravity estimate errors.

2) In vector gravimetry:  Simultaneous determination of three components of the gravity disturbance vector from airborne measurements at the flight path.

Both developed algorithms use an a priori spatial gravity model based on parameterizing the disturbing potential in the survey area by three-dimensional harmonic spherical scaling functions (SSFs). The algorithm developed for solving Problem 1 provides estimates of the unknown coefficients of the a priori gravity model using a least squares technique. Due to the assumption that the along-line gravity estimate errors at any two lines are not correlated, the algorithm has a recursive (line-by-line) implementation. At the last step of the recursion, regularization is applied due to ill-conditioning of the least squares problem. Numerical results of processing the GT-2A airborne gravimeter data are presented and discussed.

To solve Problem 2, one need to separate the gravity horizontal component estimates from systematic errors of the inertial navigation system (INS) of a gravimeter (attitude errors, inertial sensor bias). The standard method of gravity estimation based on gravity modelling over time is not capable to provide accurate results, and additional corrections should be applied. The developed algorithm uses a spatial gravity model based on the SSFs. The coefficients of the gravity model and the INS systematic errors are estimated simultaneously from airborne measurements at the flight path via Kalman filtering with regularization at the last time moment. Results of simulation tests show a significant increase in accuracy of gravity vector estimation compared to the standard method.

This research was supported by RFBR (grant number 19-01-00179).
Proximal remote sensing to quantify plot-scale overland flow connectivity
Authors: Ghimire Chandra Prasad , Snow Val , Bradley Stuart , Grundy Laura
Published: March 2020

Irrigation of crops and grazed pastures can lead to harmful losses of nutrients via overland flow across the edge of the field. While good irrigation design can assist with avoiding overland flow, soil surface conditions can change rapidly and lead to surface flow even under well-designed irrigation systems. Therefore, real-time methods to detect emerging flow conditions, early enough to prevent substantial flow from the field during irrigation, is a potential mitigation option. But these methods require a prediction of the initiation of overland flow conditions in order to make the connection with real-time observations.

On a naturally-rough agricultural soil, triggering of overland flow is primarily related to the process of gradual filling of small (~50 mm across) depressions. As depressions fill, hydraulic connections are established with their neighbours and this eventually leads to sufficient connectivity that overland flow is initiated. The initiation of overland flow generally occurs at a critical value of connectivity (COF); the proportion of the soil surface that is connected via a water-filled pathway to an exit point of the field. As water ponding in, and flowing through, local depressions increases, the COF of the field increases and this leads to flow across the field boundaries. Quantifying the development of COF during an irrigation event, therefore, is key to predicting the initiation of overland flow.

We propose a method to continuously monitor the development of COF during an irrigation event that requires two elements. The first is a new proximal sensing technique, which exploits acoustic technology to continuously monitor Asw, the proportion of the soil surface covered in water. The acoustic method comprises directional acoustic transmitter and receiver arrays. The directionality of the arrays provides a well-defined footprint area on the ground beneath the instrument. The Asw can be reliably estimated from changes in the amplitude of reflected sound waves. The second element is a ponding and redistribution model which simulates the flow of water over a rough soil surface and assists by converting Asw into COF.

Our preliminary results show that this real-time method of monitoring COF has a considerable scope in a variety of environments where prediction of overland flow initiation is desirable.
Are we reaching gender parity among Palaeontology authors?
Authors: Giles Sam , Warnock Rachel , Dunne Emma , Saupe Erin , Soul Laura , Lloyd Graeme
Published: March 2020

Women remain underrepresented in almost all areas of STEM, especially at senior levels, with palaeontology being no exception. There is a widespread perception that the situation is improving, and that it is simply a matter of time before this improvement is reflected at higher career stages. However, there is strong evidence that formidable barriers remain for women in palaeontology. We must question how much progress towards gender equality has been made in order to continue on a path towards equity. With a view to contributing quantitative data to this discussion, we examine whether the proportion of women publishing in palaeontology is approaching parity, using data from the journal Palaeontology as a proxy for the discipline. This work was motivated by the sense that, despite increased representation of women, articles on palaeontological subjects almost never appear to have over 50% women authors. Indeed, we find that women account for less than 20% of authors and, perhaps more surprisingly, there has been no substantial increase in the proportion of women contributing to the journal over the past 20 years. The percentage of articles in which women make up more than 50% of authors remains unchanged. The proportion of articles on which women are absent from the author list is decreasing, but this partly reflects an increase in the average number of authors per article. Our findings match those found in broader studies of the scientific literature, including those within the biological and Earth Sciences, which generally find that women make up less than 30% of authors. We highlight important barriers that remain for women and other under-represented groups in science, and make several recommendations to help improve their representation in palaeontology. Key recommendations include: acknowledging and engaging with diversity issues; targeted recruitment of women to all levels of academic publishing; actively promoting individuals from all underrepresented groups, especially those at the intersections of multiple minoritized identities; and collecting relevant data and perspectives.
Circulation patterns and eutrophication phenomena in the Thermaikos Gulf
Authors: Krestenitis Yannis N. , Kolovoyiannis Vasilis , Androulidakis Yannis , Makris Christos , Baltikas Vasilis
Published: March 2020

Thermaikos Gulf, located in the Northwestern Aegean Sea (Greece), is a marine ecosystem of major importance, not only environmentally (as an area of the deep water formation with contribution to the renewal of the North Aegean deep waters), but also due to the various socioeconomic activities associated with the area. Observational and simulated data are used to investigate the evolution of eutrophication events during the last two years in order to evaluate the current (2017-2019) quality state of the seawater in the Gulf. The quality of the marine environment of Thermaikos Gulf was appraised by measuring physical, chemical and biological parameters. Specific physical-chemical characteristics (temperature, salinity, density along with pH and dissolved oxygen) and biological parameters (chl-a and phytoplankton biomass) throughout the water column were evaluated by conducting in situ measurements during the sampling campaigns. Current fields, derived from a high-resolution 3-D ocean model, together with ADCP measurements, are used to describe the major circulation patterns, the river plume dynamics and the renewal pathways of the Gulf. The obtained results are discussed with regards to seasonal and spatial variability, and the water column stratification. Satellite ocean color data were also used to discuss the in-situ findings and confirm “Dirty” Sea and Red Tide phenomena, that were detected and analyzed based on the physical dynamics and especially the renewal patterns of the Gulf. Moreover, we compare these recent findings to respective observations from a previous period (1997 to 2007) to evaluate potential changes in the quality state of the Gulf with respect to meteorological and river discharge conditions.     
No-till and integrated crop-livestock system ensure high rice yield through soil fertility improvement of Brazilian lowlands
Authors: Denardin Luiz Gustavo de Oliveira , Martins Amanda Posselt , Tiecher Tales , Carvalho Paulo César de Faccio , Chabbi Abad , Anghinoni Ibanor
Published: March 2020

Lowland soils represent 4 to 6% of the earth's surface, covering an area of 7 to 9 million km2. Most of these areas can be used for flooded rice cultivation, as a paddy field. These soils commonly have low fertility due to the traditional flooded rice cultivation systems, which are based on intensive soil tillage and rice monocropping. On the other hand, soil conservation management systems, such as no-tillage and integrated crop-livestock systems (ICLS) may increase the soil fertility and consequently improve rice yield. In lowlands, these practices are contributing to sustainable soil management. Therefore, our study aimed to evaluate soil fertility properties by measuring soil organic matter (SOM) and soil available phosphorus (P) and potassium (K) contents, five years after the adoption of different paddy-farming systems in an Albaqualf soil. The long-term ICLS experiment is located in Cristal county, Rio Grande do Sul State, in Southern Brazil. The systems consisted of two ICLS under no-tillage (NT), in comparison to the traditional system (S1) of flooded rice cultivation under soil disturbance, rice monocropping, and winter fallow. The ICLS systems were based in: rice cultivation in summer season and pasture (annual ryegrass) with cattle grazing in winter season (S2), and crop rotation (rice and soybean) in summer season and livestock production in winter season (S3). In 2013, at the beginning of the experiment, and after five years (2018), soil samples were collected in the 0–10 and 10–20 cm layers, and then the SOM, and available P and K contents were analyzed. Regarding the rice yield, S2 and S3 always had higher rice yields than S1. The S2 and S3 showed increases in yields of 8.9 and 16.4% in relation to S1, with average yields of 11.3 and 12.1 Mg ha-1, respectively. In addition to S3 having the highest rice yields, it also had high soybean yields for lowland environment in the period evaluated, with an average of 3.8 Mg ha-1. After five years, S2 and S3 increased SOM contents by 27% and 50%, respectively, in the 0–20 cm soil layer. Similar behavior was verified in available P, with decrease of 4.6 mg dm-3 in S1 and increase of 16.0 mg dm-3 in the S3 compared to the initial evaluation. The available K content was higher in S3 (79.3 mg dm-3), followed by S2 (68.1 mg dm-3) and S1 (59.5 mg dm-3) on average of two years evaluated, in the 0–10 cm soil layer. Therefore, the results shows that NT adoption, combined with crop rotation and ICLS, improve soil fertility attributes, which results in high rice yields over time, reaching the sustainable intensification of lowlands.
New insights into North Sea tunnel valley infill and genesis from high-resolution 3D seismic data
Authors: Kirkham James , Hogan Kelly , Larter Robert , Self Ed , Games Ken , Huuse Mads , Stewart Margaret , Ottesen Dag , Arnold Neil , Dowdeswell Julian
Published: March 2020

Tunnel valleys are large (kilometres wide, hundreds of metres deep) channels incised into bedrock and soft sediments by the action of pressurised subglacial meltwater. Discovered over a century ago, they are common across large swathes of North-West Europe and North America. However, many aspects of tunnel valley formation, and the processes by which they are infilled, remain poorly understood. Here, we use new high-resolution 3D seismic reflection data, collected by the geohazard assessment industry, to examine the infill lithology and architecture of buried tunnel valleys located in the central North Sea. The spatial resolution of our seismic data (3.125-6.25 m bin size) represents an order of magnitude improvement in the data resolution that has previously been used to study tunnel valleys in this region, allowing us to examine their infill in unprecedented detail. Inside the tunnel valleys, we identify a suite of buried subglacial landforms, some of which have rarely been reported inside tunnel valleys before. These landforms include a 14-km-long system of segmented eskers, crevasse-squeeze ridges, subsidiary meltwater channels and retreat moraines. Their presence suggests that, in some cases, tunnel valleys in the North Sea were reoccupied by ice following their initial formation, casting doubt on hypotheses which invoke catastrophic releases of water to explain tunnel valley creation.
Integrated microgravimetric and seismic monitoring approach in the Þeistareykir volcanic geothermal field (North Iceland).
Authors: Schäfer Florian , Jousset Philippe , Toledo Tania , Güntner Andreas , Schöne Tilo , Naranjo David , Erbas Kemal , Juliusson Egill , Warburton Richard
Published: March 2020

 In volcanic and hydrothermal systems, monitoring of mass and stress changes by continuous gravity field and ground motion records provides information for both volcanic hazard assessment and estimation of geothermal resources. We aim at a better understanding of volcanic and geothermal system processes by addressing mass changes in relation with external influences such as anthropogenic (reservoir exploitation) and natural forcing (local and regional earthquake activity, earth tides). Þeistareykir is a geothermal field located within the Northern Volcanic Zone (NVZ) of Iceland on the Mid-Atlantic Ridge. Geothermal power production started in autumn 2017. For the first time on a geothermal production field, we deployed a network of 4 continuously recording gravity meters (3 superconducting meter, iGrav and one spring gravity meter gPhone) in order to cover the spatial and the temporal changes of gravity and to detect small variations related to the geothermal power plant operation (e.g. extraction and injection). All gravity monitoring stations are equipped with additional instrumentation to measure parameters that may affect the gravity records (e.g. GNSS and hydrometeorological sensors). Additionally, we deployed a temporal seismic network consisting of 14 broadband stations to enhance the seismic activity monitoring of the permanent Icelandic network in this very active region of the NVZ. Results of this unique experiment contribute to determine reservoir properties and main structures and may also reveal details of active tectonic processes. Here, we present the instrumental setup at the site and first results of more than 24 months of continuous gravity and seismicity records.
How to appreciate, use, and choose Scientific Colour Maps
Authors: Shephard Grace E. , Crameri Fabio , Heron Philip J.
Published: March 2020

The visual representation of data is at the heart of science. One of the choices faced by the scientist in representing data is the decision regarding colours. However, due to historical usage and default colour palettes on visualisation software, colour maps that distort data through uneven colour gradients are still commonly used today. In fact, the most-used colour map in presentations at the EGU General Assembly in 2018 - including Geodynamics sessions - was the one colour map that is most widely known to distort the data and misguide readers (see https://betterfigures.org/2018/04/16/how-many-rainbows-at-egu-2018/).

Here, we present the work that has been accomplished, the readily available solution, and present a how-to guide to ‚Scientific Colour Maps’ (Crameri 2018, Zenodo; Crameri et al. (In Review)), a methodology that prevents data distortion, offers intuitive colouring, and is accessible for people with colour-vision deficiencies.

Crameri, F. (2018). Scientific colour-maps. Zenodo. http://doi.org/10.5281/zenodo.1243862
Crameri, F., Shephard, G.E. Heron, P.J. Advantage, availability, and application of Scientific Colour Maps. (In Review with Nature Communications)
Diurnal Self-Aggregation
Authors: Haerter Jan O. , Meyer Bettina , Nissen Silas Boye
Published: March 2020

Convective self-aggregation is a modelling paradigm for thunderstorm organisation over a constant-temperature tropical sea surface. This setup can give rise to cloud clusters over timescales of weeks. In reality, sea surface temperatures do oscillate diurnally, affecting the atmospheric state. Over land, surface temperatures vary more strongly, and rain rate is significantly influenced. Here, we carry out a substantial suite of cloud-resolving numerical experiments, and find that even weak surface temperature oscillations enable qualitatively different dynamics to emerge: the spatial distribution of rainfall is only homogeneous during the first day. Already on the second day, the rain field is firmly structured. In later days, the clustering becomes stronger and alternates from day to day. We show that these features are robust to changes in resolution, domain size, and surface temperature, but can be removed by a reduction of the amplitude of oscillation, suggesting a transition to a clustered state. Maximal clustering occurs at a scale of lmax≈180 km, a scale we relate to the emergence of mesoscale convective systems. At lmax rainfall is strongly enhanced and far exceeds the rainfall expected at random. We explain the transition to clustering using simple conceptual modelling. Our results may help clarify how continental extremes build up and how cloud clustering over the tropical ocean could emerge much faster than through conventional self-aggregation alone.
Cenozoic affinity of the Gondwanan rocks of eastern Timor: evidence from geo-thermochronometry
Authors: Duffy Brendan , Lew Brian , Boland Kevin , Kohn Barry , Matchan Erin , Maas Roland , Dixon David , Pedro Lourenço , de Carvalho Paulo , Sandiford Mike
Published: March 2020

Timor occupies a critical position within Wallacea and within the Indonesian throughflow, but its tectonic history remains poorly constrained compared to other parts of the region. Tectonic models typically divide the island into 1) Australian affinity rocks, including a thick sequence of Paleozoic and Mesozoic rocks and metamorphosed equivalents, and 2) Asian affinity rocks, made up of predominantly Cretaceous and Paleogene rocks and their metamorphosed equivalents, known as the Lolotoi Metamorphic Complex (LMC). New field mapping shows that the type-area of the LMC is pre-Permian basement exposed in an erosional window. Much of the previously mapped LMC is actually overlying alkaline Permian basalt. LA-ICPMS U-Pb ages for zircons, apatites and titanites from the LMC type-area are Precambrian and consistent with those from Gondwanan continental slivers that now form the basement of eastern Java and West Sulawesi. Such basement ages are also identified in peaks from inherited zircons from the LMC elsewhere in Timor. Basement faults separating the LMC from Triassic and Jurassic sediments contain white micas yielding Ar-Ar ages of c.38 Ma, which are within the age range of white micas from the Asian affinity Mutis metamorphic complex of West Timor. Zircon and apatite (U-Th)/He thermochronometric data and low vitrinite reflectance values across much of the study area do not support previous models suggesting Cenozoic overthrusting. However, close to the basement fault the thermochronometric data indicate rapid Eocene-Oligocene cooling and like the white mica ages, this is consistent with the thermal history of the Mutis complex of West Timor. On the basis of these data, we revive Barber’s (1978) interpretation that almost all of the pre-Neogene exhumed rocks of eastern Timor, including the Gondwanan rocks, resided in Sundaland during the Cenozoic. This finding has implications for the geodynamics of the Banda Arc, reconstructions of Wallacea, and the Neogene paleogeography of the Indonesian Throughflow.
Projections and simulation of water balance in the Southern Ice Field, Patagonia, Chile
Authors: Jerez Toledo Catalina , Vargas Mesa Ximena
Published: March 2020

The Southern Ice Field (CHS) corresponds to one of the largest continental ice plains, representing a water source for the entire globe. It extends from 40°20' S to 51°30' S, covering an area of approximately 16.800 km2 and consisting of 49 glaciers distributed in the southern territory of Chile and part of the Argentine Patagonia. Due to climatic change, the CHS has been affected, like all the ecosystems that compose the planet, generating disturbances in their natural state, consequently, the systems that constitute the CHS tend to look for a new balance. However, the new state(s) of equilibrium can present a great deal of variability, which is why the Intergovernmental Panel on Climate Change (IPCC) has drawn up the Representative Concentration Pathways (RCP), which aim to account for the effects of climate change by representing the total radiative forcing calculated for the year 2100 and including the net effect of Greenhouse Gases (GHG), in addition to other anthropogenic forcing. Based on this, the main objective of the present study is to give an account of a projection and simulation of the water balance in the CHS, informing about the physical processes occurred in the historical period (1970 - 2005), the current period considering a near past and future (2006 - 2050) and a projection to the distant future (2051 - 2100). The simulation of the water balance considers two General Circulation Models (GCMs: MPI-ESM and CSIRO-Mk3-6-0), which are numerical models frequently implemented to simulate the effects of climate change. These models are evaluated under two RCP scenarios 4.5 and 8.5, giving the most unfavorable results under the latter scenario when evaluating the CSIRO-Mk3-6-0 model, since temperature increases of up to 8°C and an oscillating precipitation regime are observed. On the other hand, the MPI-ESM model indicates increases of 1.5°C and 2.5°C accordingly to each scenario and decreases of ± 1/3 of the current observed precipitation. Both models, when evaluated in the previously mentioned scenarios, indicate that the basins that make up the CHS present an emptying to a greater or lesser degree according to the scenario, for which reason, the ice mass that makes up the CHS will follow the behavior it has experienced up to now and will continue to detach itself. To this last, we must add the effect of the decreases in precipitations that reach an average deficit of 30 mm by year 2050 and increases in temperature that exceed the values reported by the IPCC (2019), which they look for to control the effects of the climatic change in the present situation.
Shock wave properties in the solar corona and their associations with multi-spacecraft solar energetic particle events measured near 1AU.
Authors: Kouloumvakos Athanasios , Rouillard Alexis P.
Published: March 2020

STEREO has provided over 10 yr of continuous monitoring of CMEs and CME-driven shock waves from the Sun to Earth-like distances, as well as multipoint measurements of SEPs in the keV to 100 MeV energy range. These observations have revealed a number of puzzling properties of SEPs. For instance, gradual and impulsive SEP events have been measured over extended ranges of longitudes by STEREO, sometimes extending over 360 degrees around the Sun. Multi-spacecraft remote-sensing observations have allowed us to perform shock wave modeling in 3D, and to derive and examine consistently critical shock parameters during their evolution. I will present a connection of the shocks/CMEs to SEP properties from multi-spacecraft in-situ measurements by alleviating projection effects, accounting for both the complexities of coronal shocks and how they are likely to connect magnetically with in-situ spacecraft. A comparison between the shock wave parameters derived from 3D modeling and observations, and SEP characteristics confirm predictions of diffusive shock acceleration, that efficient acceleration of SEPs should naturally occur at shock regions where the shock Mach number is high. I will also discuss how modeling shock waves and estimating their magnetic connectivity can be useful in future studies to determine the solar origin of particle events measured by Parker Solar Probe.
Amphibole lamellae formation in the upper mantle due to interaction of fluid inclusions and host minerals: a case study from Persani Mountains Volcanic Field, Transylvania
Authors: Lange Thomas Pieter , Pálos Zsófia , Patkó Levente , Berkesi Márta , Liptai Nóra , Aradi László Előd , Szabó Ábel , Szabó Csaba , Kovács István János
Published: March 2020

Amphibole is one of the most abundant ’water’-bearing minerals in the Earth’s upper mantle. Amphiboles occur as interstitial grains, lamellae within pyroxenes or as daughter minerals within fluid inclusions.  Most commonly amphibole formation is related to mantle metasomatism, where the agent has a subducted slab (e.g. Manning 2004) or an asthenospheric origin (e.g. Berkesi et al. 2019).  After the formation of fluid inclusions, a subsolidus interaction can take place where the H2O content of fluid inclusions may crystallize pargasite (e.g. Plank et al. 2016).

Here we present amphibole lamellae formation in mantle xenoliths from the Persani Mountains Volcanic Field that is interrelated to a reaction between fluid inclusions and host clinopyroxene.  Newly formed amphibole lamellae occur only in the surroundings of the fluid inclusions and grow within the host clinopyroxene in a preferred crystallographic direction.  Studied lamellae do not reach the rim of the host mineral implying that components needed for formation of amphibole lamellae in clinopyroxene could have only originated from the fluid inclusion itself.  We measured the major element composition of amphibole lamellae and host clinopyroxene (1) and used Raman spectroscopy and FIB-SEM on fluid inclusion study situated next to the lamellae (2).  Results support the hypothesis that chemical components (dominantly H+) migrated sub-solidus from the fluid inclusion into the host mineral after fluid entrapment via subsolidus interaction.  Beyond the clinopyroxene-hosted fluid inclusions, fluid inclusions in orthopyroxenes were also studied as a reference.  Our study shows that post-entrapment diffusion from a fluid inclusion into the host mineral changes the solid/fluid ratio of the mantle  which could modify the rheology of the lithospheric mantle.

Berkesi, M. et al. 2019. Chemical Geology, 508, 182-196.

Kovács et al. (2017) Acta Geodaetica et Geophysica, 52(2), 183-204.

Manning C. E. 2004. Earth and Planetary Science Letters, 223, 1-16.

Plank, T. A. et al. 2016. In AGU Fall Meeting Abstracts.
An innovative ASV for the monitoring of anthropogenic pressure on Wetlands
Authors: Odetti Angelo , Bruzzone Gabriele , Bibuli Marco , Ferretti Roberta , Zereik Enrica , Caccia Massimo
Published: March 2020

This paper describes the technological development of an innovative Autonomous Surface Vehicle designed to meet the requirement of accessing the extremely shallow waters peculiar of the Wetlands. Wetlands are those geographic areas where water meets the earth and cover between 5 and 8 % of the Earth's surface. Wetlands include mangrove zones, swamps, bogs and marshes, rivers and lakes, alluvial plains and flooded forests, shallow coasts and coral reefs. In recent years, their importance is becoming more and more recognized and various international conventions, directives and projects work on the protection of these fundamental ecosystems. Wetlands are considered among the world’s most productive environments for their biological diversity. Nevertheless the number, quality and spacial resolution of surveys in these peculiar environments is reduced due to the absence of suitable tools expressly addressed to work in these areas. This reduces the possibilities of monitoring and protecting the Wetlands. In this paper the first prototype of an innovative class of reliable modular re-configurable lightweight ASVs for extremely shallow water and remote areas applications is presented. SWAMP (Shallow Water Autonomous Multipurpose Platform) is a fully electric, modular, portable, lightweight, and highly-controllable Autonomous Surface Vehicle (ASV). It is a catamaran equipped with azimuth pump-jet actuators, and it is characterized by small draft soft-foam, unsinkable hull structure with high modularity and a flexible hardware/software architecture. The main advantage of pumpjet motors is that they are flush with the hull, thus minimizing the risks of damages due to possible grounding. This system is used to increase the manoeuvrability in narrow spaces and to increase the special resolution also in extremely shallow waters. The introduction of a soft hull structure is suitable for working in coastal areas and in riverine environment where impacts can affect the survival of the robot. The foam of the hulls is drilled in order to make SWAMP a completely modular catamaran that is able to host various types of tools, such as intelligent systems, samplers, and sensors, together with thrusters that are, in this way, protected by the foam. A preliminary study is shown related to the bathymetry carried on with a single beam sonar in a Ligurian river after a series of floods. Liguria is one of the European regions where extreme events related to anthropic changes have had the greatest number of negative effects. In this kind of areas the use of suitable robots can improve the assessment and monitoring the impact of anthropogenic pressure in wetland ecosystems.
Does optimal estimation perform adequately for hyperspectral surface reflectance retrieval?
Authors: Susiluoto Jouni , Turmon Michael , Carmon Nimrod , Thompson David
Published: March 2020

The current and coming imaging spectroscopy missions (EMIT, ECOSTRESS, AVIRIS-NG), and observables for potential future missions studying Surface Biology and Geology (SBG) observe a wide range of spectral bands, which can be used to infer about surface properties. The current state of the art approach for performing the retrieval of surface reflectance is optimal estimation (OE), which amounts to finding the maximum a posteriori estimate of the surface reflectance, after which the posterior covariance is approximated by linearizing the forward model (Rodgers, 2001). While this method has a principled basis and often performs well, with challenging atmospheres the optimization may fall into local minima, or the estimated posterior mean and covariance may be wrong.  Addressing these failures under realistic observing conditions is particularly important to realize the full potential of upcoming global observations.                                                                                                                                                                        

As a preparation to improving the quality of future retrievals, we evaluate the performance of OE against posteriors generated with advanced Bayesian techniques.  We present results from comparing the OE posterior mean and covariance to the true posterior, as computed by MCMC, for moderately challenging atmospheric conditions, and an instrument configuration consistent with AVIRIS-NG. 
Hydrological Connectivity: A Useful framework to identify degradation thresholds in semiarid landscapes.
Authors: Sandi Steven G. , Saco Patricia M. , Rodriguez Jose F. , Moreno-de las Heras Mariano , Azadi Samira
Published: March 2020

Over the last few years, the concept of hydrological connectivity has emerged as a useful framework to quantify how changes in water redistribution and sediment production may lead to land degradation. Here, we illustrate the use of the connectivity framework for several examples of dryland systems that are analysed at a variety of spatial and temporal scales using both modelling approaches and remote sensing data analysis. We show that hydrological connectivity is particularly useful in drylands where human and/or natural disturbances can alter the surface water availability and pathways, and therefore the system connectivity. In doing so, we also focus on the analysis of co-evolution of system structures and function, and how they may drive threshold behaviour leading to desertification. We apply the framework to different dryland systems, starting with the analysis of semi-arid rangelands, where feedbacks between the decline in vegetation density and landscape erosion reinforces degradation processes driven by changes in connectivity. We then focus on semi-arid floodplain wetlands, where decreases in water volumes promote terrestrial vegetation encroachment that changes drainage conditions and connectivity, potentially reinforcing redistribution of flow paths to other wetland areas. In both cases, crossing a system threshold might lead to degradation in which the return to a functional system is unlikely. The examples presented highlight the need to incorporate a co-evolutionary framework for the analysis of changing connectivity patterns and the emergence of thresholds in arid and semi-arid systems. This framework can be used for the identification of early warning indicators of transitions from healthy to degraded states, which are useful for management applications.
Multiparametric measurements of the lava lake at Masaya volcano
Authors: Pering Tom D. , Ilanko Tehnuka , Wilkes Thomas C. , Stanger Leigh , Willmott Jon R. , McGonigle Andrew J. S.
Published: March 2020

The recent lava lake activity at Masaya volcano, Nicaragua, provided an ideal and rare moment to investigate dynamic and rapid magmatic processes. A multiparametric and low-cost approach which combined high time resolution gas, thermal, and video of the rapidly convecting lava lake was used. Gas measurements were conducted using DOAS (Differential Optical Absorption Spectroscopy) by traversing beneath the plume and Raspberry Pi ultraviolet (UV) cameras. Temperature measurements of the lake were made using a Raspberry Pi near infrared thermal camera approach. Video footage of the lava lake allowed the determination of the unusually rapid lake velocity, and crucially the generation of activity statistics such as location and frequency of the frequent small (spherical-cap) bubble bursts at the surface. Contemporaneously acquired UV and thermal datasets also allowed the assessment of a detected oscillation in the sulphur dioxide degassing data. By combing all these data streams, the unique fluid dynamics of lava lake activity at this location is highlighted.
Influence of distribution co-efficient on radionuclide transport modelling of uranium from a tailings pond in northern Karnataka, India
Authors: Ravinder Bhavya , Lakshmanan Elango
Published: March 2020

A well-designed environmental monitoring plan is essential for safety of uranium mining and processing operations. Evaluating the possible uncertainties in a numerical model helps in enhancing the model output and also increases the reliability over the model results. For a radionuclide transport model, distribution co-efficient is a sensitive parameter and major source of uncertainty in results. In this study, an approach to quantify input source of uncertainty of distribution co-efficient in an engineered tailings pond in Northern Karnataka, India has been carried out. Probabilistic analysis such as Response Surface Method and Monte Carlo Simulation are used to propagate uncertainty. This study considers uncertainty associated with intrinsic heterogeneity of natural systems and estimates the probability that dose rate value through drinking water pathway around the tailings pond exceeds the WHO guidelines for drinking water. The radionuclides considered in this study are 238U, 234U, 230Th and 226Ra. This study can be used to study the impact of distribution co-efficient on the radionuclide transport model.

Key words: Numerical modelling, Tailings pond area, Uranium mining, Uncertainty,  Distribution coefficient

 
From pre-freshet to pre-freeze: a field survey of the fate of organic matter remobilized from the thawing permafrost to the coastal waters of the Mackenzie Delta region
Authors: Lizotte Martine ,   Nunataryuk WP4 team
Published: March 2020

Thawing of permafrost in the Mackenzie Delta region of northern Canada, coupled with an increase in river discharge, prompts the release of particulate and dissolved organic matter from the largest Arctic drainage basin in North America into the Arctic Ocean. While this ongoing process is well-recognized and its rate is accelerating, the fate of the newly-mobilized organic matter as it transits from the watershed through the delta and into the marine system remains poorly understood. In the framework of the H2020 Nunataryuk project, and in partnership with ArcticNet and Sentinel North, we conducted intensive field expeditions in the Mackenzie Delta from April to September 2019. The temporal sampling scheme of this project allowed the investigation of ambient conditions in the coastal waters under a full ice cover prior to the spring freshet, during the ice break-up, in summer, as well as in fall prior to the freeze-up period. In order to capture the fluvial-marine transition zone and with specific challenges related to shallow waters and changing seasons, the field sampling was conducted using several platforms: helicopters, snowmobiles and small boats. Water column profiles of physical and optical variables were measured on site, and water and sediment samples were collected and preserved for the determination of the composition and sources of particulate and dissolved organic matter, as well as its biogeochemical cycling in the coastal environment. Beyond improving our understanding of the origin and fate of this re-mobilized organic matter, the data gathered will serve as a new basis for the ground truthing of remotely sensed images in a changing arctic environment. Finally, the tuned satellite data will be incorporated into numerical models, providing better predictions of the impacts of permafrost thaw on local biogeochemical cycling and ultimately on sea-air fluxes of carbon dioxide and global climate.