bluuebunny/crossref_metadata_2025 huggingface dataset:
Interfacial processes at dissimilarly charged mineral surfaces in contact – a surface forces apparatus study
Authors: Dziadkowiec Joanna , Cheng Hsiu-Wei , Røyne Anja , Valtiner Markus
Published: March 2020

When two mineral surfaces are in close contact, nanometers to microns apart, the proximity of another surface can significantly influence the pathways of chemical reactions happening in the interfacial region. Apart from affecting the kinetics of dissolution and nucleation reactions in spatial confinement, the proximity of charged surfaces can lead to electrochemically induced recrystallization processes. The latter may happen in an asymmetric system, in which two surfaces have a dissimilar surface charge. The charge and mass transferred during electrochemical reactions can induce dissolution or growth of solids and can significantly affect the local topography of surfaces, causing them to smooth out or to roughen. In this work, we present the experimental study of reactive mineral interfaces, immersed in geologically relevant electrolyte solutions, obtained with the electrochemical surface forces apparatus (EC-SFA). EC-SFA setup consists of one mineral surface and one gold surface (working electrode), the surface charge of which is controlled by applying an electrical potential. EC-SFA can, therefore, monitor electrochemically induced surface recrystallization processes. As the SFA technique is based on white light interferometry measurements, the changes in mineral thickness during recrystallization can be determined with an accuracy better than a nanometer over micrometer-large contact regions. Moreover, SFA allows in situ measurement of surface forces acting between mineral surfaces, which can provide additional information about how the surface reactivity influences the cohesion between mineral surfaces by modifying adhesive and repulsive forces acting between them at small separations.
A regional scale invariant depth-duration-frequency model for sub-hourly extreme rainfall estimation in Sicily
Authors: Bonaccorso Brunella , Brigandì Giuseppina , Aronica Giuseppe Tito
Published: March 2020

Depth (or intensity)-duration-frequency (DDF or IDF) curves are commonly applied in hydrology to derive storms of fixed duration and return period for hydraulic infrastructures design and risk assessment. Usually, annual maxima rainfall (AMR) data from 1 to 24-hour duration are used to develop DDF or IDF curves. However, design of urban drainage systems or flood risk assessment in small catchments often requires knowledge of very short-duration rainfall events (less than 1 hour), whose data are often unavailable or too scarce for estimating reliable quantile values. Regularities in the temporal pattern exhibited by storm records, known as scaling properties, could help in characterizing extreme storms at partially gauged sites better than the application of traditional statistical techniques. In this work, a scaling approach for estimating the distribution of sub-hourly extreme rainfall in Sicily (Italy) is presented based on data from high-resolution rain gauges with a short functioning period and from low-resolution rain gauges with longer samples. First, simple scaling assumption versus multiple scaling one is verified for annual maxima rainfall (AMR) data from 10 minute to 24-hour duration, revealing that the simple scaling regime holds from 20 to 60 minutes for most of the stations. Three scaling homogeneous regions are classified based on the scaling exponent values. In each region, this parameter is regionalized by means of power law relationships with the maximum 1 hour AMR data. Then, regional DDF curves are developed by combining the scale-invariant framework with the generalized extreme value (GEV) probability distribution, in order to estimate T-year sub-hourly extreme rainfalls at sites where only rainfall data for longer durations (≥ 1 hour) are available. The regional GEV simple scaling DDF model is validated against sub-hourly historical observations at five rain gauges. Results indicate that the proposed model provides reliable sub-hourly estimates.
Impacts of initialisation of coupled ice sheet-ocean models forecasting.
Authors: Goldberg Daniel , Holland Paul , Morlighem Mathieu
Published: March 2020

In recent years, there have been great advances in coupled ice sheet-ocean modelling, to the point where ice-ocean interactions can be represented in global climate models — with potential to greatly improve forecasting of marine ice-sheet loss and sea level rise in the coming century and beyond. However, initialisation of coupled ice sheet-ocean models has not yet been properly examined; and initialisation approaches applied to ocean and coupled atmosphere-ocean models may not be appropriate due to the long time scales inherent in dynamic ice sheets. Moreover, as ocean melt rates and ice-shelf geometry strongly influence each other, nonphysical transients in incorrectly initialised coupled ice-ocean models may persist for longer than in ice-sheet models alone.

In this work, two approaches to coupled initialisation are considered using a synchronously coupled ice-ocean model. The two approaches are based on two commonly used approaches to ice sheet model initialisation: “snapshot” calibration, where ice-sheet basal and internal parameters are configured to optimise fit with observed surface velocity; and “transient” calibration, where these parameters are configured to jointly optimise fit with velocity and geometry change; however, the transient calibration makes use of the ocean component to ensure the ice model is not subject to “initialisation shock” from ocean melting. The approaches are applied to Smith Glacier, a small but fast-thinning glacier in West Antarctica, and the model is forced under ocean warming scenarios in multidecadal runs. Initially there is much faster retreat seen in the Snapshot-calibrated simulation, but this difference decays over several decades, and ultimately the Transiently-calibrated model sees more retreat.

The experiments further suggest that Smith Glacier is not likely to exhibit Marine Ice Sheet instability in the next century. But the methods discrepancy has strong implications for glaciers which are susceptible to this instability.
Acoustic signature of fluid substitution in reservoir rocks
Authors: David Christian , Sarout Joël , Barnes Christophe , Dautriat Jérémie , Pimienta Lucas
Published: March 2020

During the production of hydrocarbon reservoirs, EOR operations, storage of CO2 underground or geothermal fluid exchanges at depth, fluid substitution processes can lead to significant changes in rock properties which can be captured from the variations in seismic waves attributes. In the laboratory, fluid substitution processes can be investigated using ultrasonic monitoring. 

The motivation of our study was to identify the seismic attributes of fluid substitution in reservoir rocks through a direct comparison between the variation in amplitude, velocity, spectral content, energy, and the actual fluid distribution in the rocks. Different arrays of ultrasonic P-wave sensors were used to record at constant time steps the waveforms during fluid substitution experiments. Two different kinds of experiments are presented: (i) water injection experiments in oil-saturated samples under stress in a triaxial setup mimicking EOR operations, (ii) spontaneous water imbibition experiments at room conditions.

In the water injection tests on a poorly consolidated sandstone saturated with oil and loaded at high deviatoric stresses, water weakening triggers mechanical instabilities leading to the rock failure. The onset of such instabilities can be followed with ultrasonic monitoring either in the passive mode (acoustic emissions recording) or in the active mode (P wave velocity survey).

In the water imbibition experiments, a methodology based on the analytical signal and instantaneous phase was designed to decompose each waveform into discrete wavelets associated with direct or reflected waves. The energy carried by the wavelets is very sensitive to the fluid substitution process: the coda wavelets are impacted as soon as imbibition starts and can be used as a precursor for remote fluid substitution. It is also shown that the amplitude of the first P-wave arrival is impacted by the upward moving fluid front before the P-wave velocity is. Several scenarios are discussed to explain the decoupling between P wave amplitude and velocity variations during fluid substitution processes.
Post-processing Hydrologic Model Output for Water Resources Studies: A Spatially-consistent, Process-based Correction Method
Authors: Bennett Andrew , Nijssen Bart , Cheng Yifan , Stein Adi , McGuire Marketa
Published: March 2020

Water resources studies often rely on simulated streamflow from hydrologic models. Model-based streamflow estimates are often not directly usable in water resources studies because all models, no matter how well-calibrated, contain systematic errors. Water resources studies rely on simulated streamflow as inputs to compute reservoir releases and diversions and do not function well if those inputs are significantly biased in time and/or space. Post-processing is therefore used to reduce these systematic errors in model outputs. This post-processing step to remove model errors is typically referred to as bias-correction, and often impacts the entire distribution of flows rather than just the mean.

Existing post-processing techniques typically have three short-comings. First, simulated streamflow at unique locations are often bias-corrected independently, disregarding the connection between locations that is imposed by the river network. This destroys the spatial consistency of the streamflow across a river network. Second, bias-correction methods often rely on simple, time-invariant mappings between observed and simulated streamflow, without regard for the different hydrological processes that drive streamflow. For example, a hydrological model may have different systematic errors in representing snowmelt than in representing soil drainage, necessitating different corrections. Third, the application of a bias-correction method is often restricted to locations where observed and simulated streamflow exist, even though these locations represent only a small subset of streamflow input locations to a water resources model.

We present a post-processing method for streamflow that addresses all three of these shortcomings of existing streamflow bias-correction methods. The method accounts for the spatial relations imposed by the river network, allows for the incorporation of process-information, and applies the bias-correction for all reaches in a stream network. We develop a mapping from the modeled output at the gages with flow observations, which we use as the basis for training a machine learning (ML) model to perform the site-specific bias-correction. We then apply the ML model to local streamflow contributions for each river segment, including river segments without flow observations. Finally, we combine the local bias-corrections across the stream network, to create accumulated bias-corrected streamflow time series that are spatially-consistent across the stream network. We demonstrate our method for daily streamflow in a river basin in the western United States.
Effects of aerosol on lightning in Sichuan Basin, Southwest China
Authors: Zhao Pengguo
Published: March 2020

The influence of aerosol on lightning is very dependent on environmental factors, including thermal factors, humidity factors, and terrain factors. ADTD cloud-to-ground lightning data, ERA5 reanalysis data, and MERRA2 reanalysis data were applied to discuss the influence of aerosol on lightning activity in Sichuan basin. Thermodynamic factors were the main reasons for the difference in lightning density between the plateau and the basin. The results showed that the influence of aerosol on lightning activity in the basin and the plateau regions showed a significant difference, showing a positive correlation on the plateau and a negative correlation on the basin. In the plateau area, the aerosol concentration was relatively low, and the aerosol stimulated the lightning activity by influencing the microphysical processes. In the basin area, the aerosol load was very high, and the aerosol showed a more significant radiation effect. By reducing the solar radiation reaching the ground, the convective energy on the ground was reduced, and the intensity of lightning activity was finally suppressed.
Evaporation measurements with an Optical-Microwave Scintillometer system over a Saline lake in the Atacama Desert
Authors: Lobos Roco Felipe , Hartogensis Oscar , Vila Jordi , de la Fuente Alberto , Suarez Francisco
Published: March 2020

Evaporation is the main water outflow and a key component of the water and surface energy balance in the endorheic basins of the Atacama Desert. This is very localized to confined environments such as saline lakes, wetlands and crop fields. In these environments, the understanding of evaporation is challenging due to the interaction between the large-scale forcing and local scale turbulence over heterogeneous surfaces. Here, the advection of momentum, heat or moisture plays an important role in the enhancement of evaporation. To understand the evaporation dynamics over such environments, we performed a comprehensive 10-days experiment: the E-DATA (Evaporation caused by Dry Air Transport over the Atacama Desert), localized under extreme conditions in the Salar del Huasco saline lake (22,3°S - 68,8°W - 3790 m a.s.l.), Chile. The measurement strategy was based on spatially distributed high-resolution surface and airborne observations in combination with WRF (Weather Research Forecasting) modeling. The main findings of the experiment show that evaporation is mainly controlled by the lack of turbulence in the morning and by regional-scale forcing in the afternoon, which leads to a sudden increase in mechanical turbulence, therefore in the evaporation flux.  

This work compares two in-situ independent measurements of surface heat fluxes over the saline lake, by using an Eddy Covariance (EC) system and an Optical-Microwave Scintillometer (OMS). Our results show in general a good agreement between EC and OMS measurements of latent (LvE) and sensible (H) heat fluxes over the water surface (R2: 0,90-0,96). During the morning, slight differences are observed between the EC and OMS measurements. However, differences up to 200 W m-2 are observed in the afternoon for LvE and up to 20 Wm-2 for H. The first analysis shows that these differences given during the afternoon are likely attributed to Monin-Obukhov stability (MOST) functions, which need to be developed yet for open water surfaces. Moreover, differences in the footprint of both measurement systems together with dramatic wind changes between the morning and afternoon may play a role. Finally, inaccurate bandpass filtering of the raw scintillometer signal may be a factor in the differences between EC and OMS, where we are currently working to refine our results. Our findings highlight the advantages and disadvantages of each measurement method over an open water body and provide a discussion about its performance.    
Living Environmental Laboratory for Lighting — A comprehensive study of interactions of artificial lighting and wildlifes
Authors: Tong Kai Pong , Kolláth Zoltán
Published: March 2020

Artificial light at night (ALAN) has become a major concern in recent years due to its impact on the health of human beings and the ecosystems. As a result, there is a surge of light pollution research not only on night sky brightness, but also on assessments of impacts on both ecology and society.

We have set up an interdisciplinary project in Hungary since September 2017, to not only study the impacts of change in lighting technology on patterns of ALAN (with emphasis on the areas within and around national parks in Hungary), but also facilitate national and international cooperations in light pollution research. We refer to this project as Living Environmental Laboratory for Lighting (LELL). Specifically, the project covers the following areas:

1. Development of new techniques for night sky radiometry and spectrometry
We are developing techniques for night sky multispectral measurements using commercially available cameras with interchangeable lens, calibrated by high sensitivity spectroradiometer, in order to quantify night sky condition and identify sources of artificial light at high resolution not achieveable by systems based on panchromatic sensors or fisheye lenses. In addition, we will compare the results from our ground-based measurements with satellite-based observations.

2. Modeling of night sky patterns in national parks of Hungary
We have developed a Monte-Carlo method of modeling light pollution, which can also be used for investigating effects of aerosols and clouds on the propagation of artificial light.

3. Impact assessments of ALAN through measurements
The public lighting was remodeled to LED-based systems in two areas close to national parks, one of which in the Zselic region in Southwestern Hungary, and another in Bükk in Northern Hungary. Using the techniques above, we are monitoring the change in night sky brightness and color, as well as the impact on flora and fauna.

4. Recommendations on future assessments and mitigations of light pollution
With our experience gain within the duration of this project, we will inform the light pollution research community of standardizing methodologies for monitoring light pollution, as well as giving recommendations for managing public lighting assets to reduce the impacts of light pollution.

Acknowledgement
This project is supported by the European Union and co-financed by the
European Social Fund (Grant no. EFOP–3.6.2–16–201–00014: Development of
international research environment for light pollution studies)
DIY approach to measuring surface water properties in the estuary
Authors: Divić Vladimir , Galešić Morena , Di Dato Mariaines , Tavra Marina , Andričević Roko
Published: March 2020

The monitoring of water bodies, specifically complex ones such as estuaries, has been historically limited. Various research efforts were hindered due to the gaps in the technology implementation and accompanied by the price of developed solutions (usually as a black box for the end-user). However, thanks to the growing trend of open source solutions both in hardware and software domain, it has become more available to apply the DIY (do it yourself) approach and build the equipment that one might need. As all frugal innovations tend to emerge from a problem that had an existing commercial solution but was too demanding on resources, the floating measurement system presented in this study was designed to get surface water properties simultaneously in multiple points. Using multiple commercial probes to do such measurements was too expensive. Therefore, we have developed an innovative low-cost drifter based on the Arduino platform as an alternative. Our device is designed to measure position, temperature, and electrical conductivity in multiple drifter realisations or short-term moored measurements. The system consists of a floating container equipped with the following components: an Arduino Mega development board, a power management module, an SD card logging module, a Bluetooth module, a temperature measuring module, a global positioning satellite (GPS) position module, and a newly developed module for measuring electrical conductivity (EC). The applicability was tested at the estuary of River Jadro near Split (Croatia) and obtained spatial data (velocity, temperature, electrical conductivity and salinity) was analysed and compared with analytical models. All used tools are open-source and greatly supported by the worldwide community. Furthermore, we consider this prototype to be one of the first steps toward development of various DIY monitoring systems with a potential for a broader range of applications. We present our work with a purpose to initiate a dialogue with more collaborators interested in developing different variations of custom-built sensors for water properties.
The sensitivity of hydrologic processes across North America considering model structure and parametric uncertainty
Authors: Mai Juliane , Craig James , Tolson Bryan , Arsenault Richard
Published: March 2020

Information on the sensitivity of model parameters and model components such as processes are essential for model development, model improvement, and model calibration, amongst others.

In this work we apply the method of the extended Sobol’ Sensitivity analysis (xSSA) which not only considers parametric uncertainty but also fully incorporates structural uncertainties (Mai et al. (2019) WRR; under review). The results of such an analysis yield not only the traditional parameter sensitivities but also sensitivities of model process options (e.g., different snowmelt algorithms) and sensitivities of model processes (e.g., snowmelt, infiltration, baseflow). 

The Raven hydrologic modelling framework (http://raven.uwaterloo.ca) allowing for flexible model structures is employed in this work. We used three options each for infiltration, quickflow, and snow melt as well as two options each for baseflow, and soil evaporation. Rather than considering 108 (3x3x3x2x2) discrete model setups, we used weighted sums of all process options yielding an infinite number of models tested.

The analysis is performed for 5797 basins across Canada (CANOPEX; Tarek et al. (2019) HESSD) and the US (USGS). The lumped basin setups use daily precipitation and  minimum/ maximum daily temperature. The sensitivity analysis is based on 20 years of daily streamflow simulations (1991-2010) after two years of spin-up (1989-1990). No observed streamflow is required for the analysis.

In total more than 450 million model runs were performed to determine sensitivities of parameters, process options and processes (51%, 35%, and 14% of model runs, respectively) across the almost 5800 basins. The computational demand was about 12 core years producing 23 TB of raw model outputs.

The analysis allows for unique, new insights into the importance of hydrologic processes and parameters (practically) independent of the model (structure) used. A few highlight results are: 1) Baseflow and other sub-surface processes are of low importance across North America- especially when time points of high flows are of interest. 2) Percolation, evaporation, and infiltration show very similar patterns with increased importance in South-eastern US and west of the Rocky Mountains. 3) Up to 30% of the overall model variability can be attributed to snow melt in regions that are snow dominated (Northern Canada and Rocky mountains). Potential melt shows a similar gradient as snow melt with sensitivities of above 60% in the Province of Quebec and the Rocky Mountains. 4) Direct runoff (quickflow) is the most sensitive of all hydrologic processes- especially in South-Eastern US it is responsible for more than 80% of the model variability.
Encouraging students to love Science
Authors: Tsioli Ioulia
Published: March 2020

Science teachers realize that the majority of students are not motivated in science in the way it is presented in the science books and school curricula. Moreover, the extensive use of mathematical equations, at an early stage, complicate things.

In addition is that the science disciplines are taught separately and in some cases the students can not realize their importance in explaining the world around us.

The aim of the Science teacher is to encourage students to love Science. It is accomplished with extra courses in different science sectors, many low-cost experiments, outdoor activities. The students are creative, make constructions, work on experiments and explain them to their classmates, play games and theatre with science background.

Each school year, another science subject is coming to our school. Meteorology (settlement of weather station, observation and  categorization of clouds, construction of wind-vanes, wind maps and rain-gauges, experiments, update the school site with the measurements of the station), Astronomy (many experiments with the light, construction of a spectroscope, construction of our planetary system in 3-d and 2-d model and a light house without bulbs and electricity but just one bottle of water on its top. Eratosthenes’ experiment is also basic), Seismology (study of geological and seismological maps, explanation of the origin of the earthquakes, why Greece has so many earthquakes and how we can protect ourselves, use of seismobox).

In the end of the year, not only the involved teachers agree that the collaboration with the students was very interesting and fruitful but also the students comment that they enjoyed and loved what happened. 

The activities of this year project will be presented in the poster.

 
A Quantitative Hydroclimatic Context for the European Great Famine of 1315-1317
Authors: Baek Seung Hun , Smerdon Jason , Dobrin George-Costin , Naimark Jacob , Cook Edward , Cook Benjamin , Seager Richard , Cane Mark
Published: March 2020

The European Great Famine of 1315-1317, in which millions starved, triggered one of the worst population collapses in European history and ranks as the single worst calamity recorded in European history in relative mortality. Historical records point to torrential rainfall, land saturation, and prolonged flooding as important causes of the event. Here we use the tree-ring based Old World Drought Atlas (OWDA) to demonstrate the full geographical extent of the pluvial that triggered the event and show 1314-1316 to be the fifth wettest three-year interval over Northern Europe from 1290 to 2000 C.E.  The spatial and temporal characteristics of our OWDA-estimated anomalies are in excellent agreement with available historical accounts, suggesting that our estimates can provide insight into hydroclimate conditions during the Great Famine over regions where historical accounts are sparse. Our estimates furthermore suggest that a dominant mode of variability not well represented in the instrumental interval likely contributed to the Great Famine.
Sapwood proportion and nitrogen content in boreal and temperate tree species
Authors: Thurner Martin , Beer Christian , Hickler Thomas
Published: March 2020

The spatial and temporal variation in plant respiration is one of the largest unknowns in the global land carbon budget. While respiration rates are directly related to temperature, plant respiration of trees is also determined by their stem sapwood proportion, tissue nitrogen (N) contents and other factors. The sapwood proportion is related to the biomass fraction of respiring living cells in the tree stem. The respiratory costs that plants have to invest to maintain basic functions (maintenance respiration) are related to the vegetation N content, since maintenance respiration supports protein repair and replacement, and most plant organic N is in proteins.

Here we explore the variation and underlying drivers in these two plant traits (stem sapwood proportion, tissue N contents) and derive novel estimates of their spatial distribution in northern hemisphere boreal and temperate forests. For the first task, we make use of measurements of sapwood and total cross-sectional area in tree stems and of N contents per dry matter in stems, roots and leaves. Such data are collected from plant trait databases like TRY, the biomass and allometry database (BAAD) and extensive literature reviews covering the most common boreal and temperate tree species. For the second task, we apply the derived tree level relationships between these traits and the underlying drivers (species, climate, soil variables) in combination with satellite radar remote sensing based products of compartment (stem, branch, root and leaf) biomass and tree species distribution maps covering the entire northern boreal and temperate forests.

We find that both the proportion of sapwood to total stem biomass and the response of the N content to environmental conditions are fundamentally different among tree genera. For instance, the sapwood proportions are spanning from 20–30% in larch to > 70% in pine and birch forests. These findings highlight the need to consider genera-specific differences when estimating the response of plant respiration to changes in climate and forest management.
Large Graupel Produced by Thin Clouds in the Arctic
Authors: Fitch Kyle , Garrett Tim , Talaei Ahmad
Published: March 2020

Riming is a critical process for both numerical modeling and microwave remote sensing because of the significant changes to hydrometeor shape and density that occur. Basic continuous collection theory invokes a simple model that assumes a relatively large, massive graupel falls through a homogeneous field of much smaller, suspended supercooled droplets in still air. However, numerous studies have shown that turbulence enhances the rate of collisions between liquid droplets, and even more so for graupel-droplet collisions. Modeling and observational studies of turbulence-induced riming enhancement have all focused on convective clouds with relatively large dissipation rates. Here we combine theoretical work on the analytical solutions of precipitation size distributions with observations and simulations of Arctic graupel to show that this enhancement is common in “thin” Arctic boundary layer clouds with LWP<50gm-2. The median enhancement of rime mass over that expected from continuous collection ranges from 6.4 to 10.7 (for collection efficiencies ranging from 1 to 0.6) for 1,628 carefully selected graupel falling from thin clouds. Analytical solutions for precipitation size distributions imply that average updraft speed must be approximately one-third of particle settling speed to explain the enhancement quantitatively using bulk cloud and precipitation measurements. Analysis of an 8-day thin cloud case revealed that the two days of thin-cloud graupel occurred in conjunction with boundary layer capping inversions that were significantly weaker than on other days of the period. These graupel days were also preceded by boundary layer profiles indicating two days of very strong cloud top radiative cooling – implying that this generated a mixed layer that eroded the capping inversion. Finally, 1-D Lagrangian simulations of graupel settling in turbulent flow show that the particles spend more time in strong updrafts where riming time increases to a significant degree. These findings challenge the current understanding of riming growth and extent turbulence-induced collision enhancement to thin mixed-phase boundary layer clouds in the Arctic. Such enhanced riming leads to increased bulk density of precipitation particles and is therefore expected have strong implications for cloud lifecycles and corresponding radiative balance in the Arctic.
Transfer of heavy metals to plants in technosols remediated with calcareous residues.
Authors: Pérez-Sirvent Carmen , Martinez-Sanchez Maria Jose , Martinez-Lopez Salvadora , Agudo Ines , Bech Jaime
Published: March 2020

When dealing with restoration and remediation projects of zones contaminated by waste and activities derived from mining operations, all the aspects that affect the neighbouring areas dedicated to the cultivation of vegetables are especially relevant, and should be carefully considered. According to previous studies carried out, the areas of mining influence affect to a very different extent the bordering areas depending not only of the characteristics of the soil but also of the type of mining activity that was developed, and so of the primary mineralogy involved, and even of the particular type of vegetable that is being cultivated. The diversity and complexity of these factors suggest the convenient of studying the process by clarifying the mechanisms of transfer of potentially toxic elements from the soil to the biotic environment, with the soil-plant-biotic chain sequence.

In this work an experimental study was carried out with this purpose making use of experiments carried out at the greenhouse scale in order to find a model that could clarify the processes that could take place in restored soils.

 

Construction and demolition residues (CDRs) as well as other residues containing high concentrations in limestone filler were used to prepare technosols, and the transfer factors (TF) and bioconcentration factors (BCF) of potentially toxic elements were measured for the selected plant species (chard and broccoli). In this way, in addition to the soil remediation, benefit can be obtained of the re-valorization of such type of  easily available, low cost residues. For the realization of the tests in the greenhouse, four technosols were prepared and experiments were planned in duplicate, which constituted eight experimental units, each one containing 21 large pots disposed in such a way that leachates were poured in the same storing tank.  

The technosols were prepared as follows:

Vegetable soil or reference soil. (T1)

Contaminated soil: 50% reference soil + 50% mine residue (T2).

Amended Land 1: 75% contaminated soil + 25% CDR (T3).

Amended soil 2: 75% contaminated soil + 25% Limestone filler (T4).

 

A statistical study was carried out to evaluate the relationships between the levels of potentially toxic elements (Pb and Cd) found in rhizospheres and root contents and the levels present in the technosols prepared. Conclusions could be obtained as regards  the mobility of  these elements, the characteristics of the technosols and the type of cultivation. The data allows a model to be outlined that could be translated at a higher scale for an effective remediation of large zones.

 

 
Supporting decision makers through rapid assessments of remote sensing data: the case of Tefé National Forest, Brazil
Authors: Moreira Pessôa Ana Carolina , O. Anderson Liana , Suertegaray Rossato Rafael , Marchezini Victor , Pechini Bento Bruna Maria , Maruã Ortiz Siani Sacha , Costa Alencar Ane Auxiliadora , de Castro Silva Isabel , Harding Torfinn
Published: March 2020

Providing scientific subsidies for public policies is a compromise that is beyond the boundaries created by the academic universe, requiring scientists to respond to the challenges posed by increasingly complex societies, both socially and environmentally. Considering this, the objective of this work was to build a pilot project for rapid assessment of Tefé National Forest (TNF) land use zoning and evaluate its relevance as a tool to support actions and influence discussions in protected area management councils.

The assessment considered remote sensing data on deforestation and fire from 2005 to 2015. Deforestation maps (PRODES-INPE) and active fire (MODIS) information were overlapped with TNF land use zoning. Although National Forest, in general, has its land use rules provided by law, each protected area defines on its Management Plan their own land use zoning, with specific rules.

The study showed that in 2015, 97% of TNF was covered by forest, and although no deforestation was recorded in the same year, the number of active fires was 1.8 times higher than the average from 2005 to 2014. This demonstrates the vulnerability of this area to the extreme drought which affected the region this year. The Population Zone, where 44% of the TNF population lives, recorded the highest rates of deforestation and fire. The Preservation Zone, on the other hand, showed to be fulfilling its function, presenting no active fires and only one deforestation event during the whole analyzed period.

These results were presented at the 20th TNF Council Meeting, in 2017. The TNF manager pointed out the great importance of spatial and temporal diagnoses, which can exert in prioritize actions to tackle specific problems in most threatened zones. Community leaders participating in the meeting contributed to the completion of the results with in situ day-to-day reports, offering hypotheses for some phenomena observed on the assessment, such as the deforestation observed in 2010. After that, it became clear that actions directly focused on the Population Zone, and mainly related to the use of fire in years of extreme drought, can improve the conservation outcome for this protected area. Integrated socio-environmental diagnosis, such as this pilot project, can be an important tool, allowing a broader version of the monitoring strategies.
Demonstrating sustainable land management and delivering multiple environmental, economic and social benefits in Australian pastoral systems.
Authors: Waters Cathleen , Orgill Susan , Ogilvy Susan , Simmons Aaron
Published: March 2020

Globally, grazing systems have been consistently implicated in land degradation as reflected by changes in woody cover, soil degradation and losses of biodiversity. Pastoral systems can be a major contributor to global greenhouse gas (GHG) emission or a low-cost carbon sink for climate mitigation. In Australia, the $AUD 2.55 billion Emissions Reduction Fund (ERF) is the centre piece of climate policy and has resulted in >3.8 million ha of land use change. Traditional pastoral systems are now including management which increases carbon pools in vegetation (regeneration of native vegetation in rangelands) and soils (regenerative pasture management to increase the amount of soil biomass and limit soil disturbance). The scale of this land-use change is providing an unpredicted opportunity to deliver multiple ecosystem services, or core benefits (production of food and fibre, carbon sequestration and reduced loss of soil carbon). While there is increasing anecdotal evidence that regenerative agricultural practices results in increased farm profitability and greater wellbeing, there are key uncertainties around their potential to deliver multifunctional landscapes and contested views on the magnitude of these changes and opportunities. A major uncertainty revolves around climate impacts on carbon sequestration.

We provide two case studies which explicitly incorporate carbon sequestration and regenerative management practices and have the potential to deliver multiple environmental, economic and social benefits; (i) using a rangeland carbon farming example, we show how income from carbon sequestration in vegetation, re-directed to managing of grazing intensity, is leading to greater ecological and social resilience. Additional value of these carbon farming areas through ecological thinning and the use of woody residue for biochar production represents further mitigation potential as well as increased benefits in habitat for biodiversity (ii) using a temperate grazing system, implementing regenerative agricultural practices which reduce the amount of soil organic matter decline through minimal disturbance and pasture management may increase soil organic carbon. For each case study, Land Use Trade-Offs (LUTO) model, a high-resolution integrated environmental-economic model, is used to illustrate spatiotemporal dynamics of land-use options, quantify the magnitude of trade-offs adjusted for future climate impacts and assess farm-scale land use prioritisation and optimisation for multiple benefits. We identify land management practices that increase carbon sequestration (vegetation and soils) and realise opportunities for additional farm income are integrated with sustainable land management.
Application of deep recurrent neural networks for modeling surface and sub-surface flow at high temporal resolution
Authors: Abbas Ather , Baek Sangsoo , Kim Minjeong , Ligaray Mayzonee , Ribolzi Olivier , Silvera Norbert , Min Joong-Hyuk , Boithias Laurie , Cho Kyung Hwa
Published: March 2020

Recent increase in climate change has resulted in rise of hydrologic extreme events, which demands better understanding of flow patterns in catchment. Modeling surface and sub-surface flow at high temporal resolution helps to understand catchment dynamics. In this study, we simulated surface and sub-surface flow in a Laotian catchment at 6-minute resolution. We used one physically based model called Hydrological Simulated Program-FORTRAN (HSPF) and developed two deep learning-based models. One deep learning model consisted of only one long short-term memory (LSTM), whereas the other model simulated processes in each hydrologic response unit (HRU) by defining one separate LSTM for each HRU. The models consider environmental data as well as changing landuse in catchment and predict surface and sub-surface flows. Our results show that simple LSTM model outperformed other models for surface runoff prediction, whereas the HRU-based LSTM model better predicted patterns and slopes in sub-surface flow in comparison with other models.
Status, Changes and Impacts of Permafrost on Qinghai-Tibet Plateau
Authors: Zhao Lin , Hu Guojie , Zou Defu , Li Ren , Sheng Yu , Pang Qiangqiang
Published: March 2020

Due to the climate warming, permafrost on the Qinghai-Tibet Plateau (QTP) was degradating in the past decades. Since its impacts on East Asian monsoon, and even on the global climate system, it is fundamental to reveal permafrost status, changes and its physical processes. Based on previous research results and new observation data, this paper reviews the characteristics of the status of permafrost on the QTP, including the active layer thickness (ALT), the spatial distribution of permafrost, permafrost temperature and thickness, as well as the ground ice and soil carbon storage in permafrost region.

The results showed that the permafrost and seasonally frozen ground area (excluding glaciers and lakes) is 1.06 million square kilometters and 1.45 million square kilometters on the QTP. The permafrost thickness varies greatly among topography, with the maximum value in mountainous areas, which could be deeper than 200 m, while the minimum value in the flat areas and mountain valleys, which could be less than 60 m. The mean value of active layer thickness is about 2.3 m. Soil temperature at 0~10 cm, 10~40 cm, 40~100 cm, 100~200 cm increased at a rate of 0.439, 0.449, 0.396, and 0.259°C/10a, respectively, from 1980 to 2015. The increasing rate of the soil temperature at the bottom of active layer was 0.486 oC/10a from 2004 to 2018.

The volume of ground ice contained in permafrost on QTP is estimated up to 1.27×104 km3 (liquid water equivalent). The soil organic carbon staored in the upper 2 m of soils within the permafrost region is about 17 Pg. Most of the research results showed that the permafrost ecosystem is still a carbon sink at the present, but it might be shifted to a carbon source due to the loss of soil organic carbon along with permafrost degradation.

Overall, the plateau permafrost has undergone remarkable degradation during past decades, which are clearly proven by the increasing ALTs and ground temperature. Most of the permafrost on the QTP belongs to the unstable permafrost, meaning that permafrost over TPQ is very sensitive to climate warming. The permafrost interacts closely with water, soil, greenhouse gases emission and biosphere. Therefore, the permafrost degradation greatly affects the regional hydrology, ecology and even the global climate system.
Possible Effects of Climate Change on New Zealand Design Wind Speeds
Authors: Safaei Pirooz Amir Ali , Flay Richard G.J. , Turner Richard , Azorin-Molina Cesar
Published: March 2020

The climate is changing, and as a result, the Earth could experience more severe extreme weather events. Growing interest and concern about the effects of climate change on cities, infrastructures and people’s lives raises the question “how are design wind speeds influenced by different climate change scenarios?”. This study aims at (i) analysing the gust wind records of four meteorological stations across New Zealand for the period 1972-2017; (ii) investigating whether or not the long-term wind gust series have changed significantly; and (iii) how these changes can be considered in the estimation of design wind speeds to ensure the safety and reliability of the future structures.

Historical hourly and daily gust wind speed series recorded at the four selected stations were subjected to a robust quality control and homogenisation protocol to ensure all the artificial inhomogeneities resulting from factors like station relocations, anemometer height changes, instrumentation malfunctions, instrumentation changes, different sampling intervals, and observation environment changes, have been eliminated prior to any subsequent analyses. Then, annual and seasonal trends in both magnitudes and frequencies of the extreme winds were evaluated as to whether the observed trends are statistically significant or not by calculating p-values. From the derived gust trends, some recommendations are proposed for consideration in regard to revising the design wind speeds for calculating the wind loads on structures. In addition, the findings of the study are compared with gust wind speed trends in several other countries and also with IPCC 5th assessment projections for New Zealand [1].

The main findings of this research are summarised as follows:

The magnitude and frequency of wind gust showed negative (significant for some stations and seasons) trends.

This result suggests that at this stage no extra multiplier is required to be applied to the New Zealand design wind speeds.

Additional analyses of the long-term wind gust trends at more stations across New Zealand are needed.

 

Reference

[1] Ministry for the Environment 2018. Climate Change Projections for New Zealand: Atmosphere Projections Based on Simulations from the IPCC Fifth Assessment, 2nd Edition. Wellington: Ministry for the Environment.
Stratigraphic heterogeneity in the Yangtze River subaqueous delta revealed by chronological and mineral magnetic approaches
Authors: Cheng Qinzi , Wang Feng , Chen Jin , Ge Can , Chen Yinglu , Zhao Xuanqi , Nian Xiaomei , Zhang Weiguo , Liu Kam-biu , Xu Yijun , Lam Nina
Published: March 2020

Delta deposits show large spatial heterogeneity in terms of depositional rate and age, which is critical to the study of delta erosion in response to the declining fluvial sediment load observed at many river mouths in the world. In this study, we demonstrate the magnetic susceptibility (χ) as a rough indicator to reveal age variations and stratigraphic heterogeneity in the Yangtze River subaqueous delta. Ages of three short sediment cores (<2 m) collected at 20-32 m water depth from the Yangtze River subaqueous delta were determined using 210Pb, 137Cs, and optically stimulated luminescence (OSL) dating. In addition, depth variation of χ, which is influenced by post-depositional diagenesis and hence age, was used to roughly estimate sediment ages among the cores in a quick way. The profiles of 210Pb, 137Cs, and OSL results indicate the spatial variability of ages, ranging from the last 100 years to more than 2000 years. Cores at shallow water depths are younger than those from deeper sites. Modern deposits (i.e., <100 years old) occur primarily at water depths shallower than ca. 30 m, which can be explained by the trapping depth of bottom plumes. The Core in the northern part of the subaqueous delta shows much older ages than the core at the southern site with similar water depth, which is caused by their distance relative to the mouth of active sediment discharge distributary. Profile of χ confirms such spatial variation of ages in terms of depth distribution pattern and χ value. Older sediments show lower and uniform χ values due to the reductive dissolution of ferrimagnetic minerals, while younger sediments show higher χ values in the top layer but they decline with increasing depth. Considering the quick way of magnetic measurement, stratigraphic correlation based on χ can be used first to screen for cores before they are subjected to more detailed dating. This study shows that the methodological approach of combining sediment dating with magnetic measurement has great potential in revealing heterogeneous deltaic deposits, which could be easily neglected in morphodynamical and biogeochemical study.