bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term geophysical-geotechnical monitoring of landslide processes
Authors: Chambers Jon ,   Landslide Geophysics Consortium
Published: March 2020

We assess the use of novel geophysical monitoring approaches to spatially characterise geotechnical properties and processes driving slope failure, and consider the contribution of geophysical technologies to the development of slope-scale early warning systems (EWS). In particular, we focus on geoelectrical monitoring approaches to image moisture driven processes, supported by the use of shallow seismic surveys to illuminate elastic property distributions and changes. We describe an approach for using spatial and volumetric geophysical models of slope structures and processes to better inform geotechnical models of slope stability and estimates of factor of safety.

Key components of the approach have included: automated schemes and instrumentation for measuring and processing field-scale time-lapse geophysical and geotechnical data sets; laboratory based assessments of geophysical-geotechnical property relationships (e.g. between resistivity, moisture content and pore suctions) to aid the interpretation of slope-scale geophysical models; and linked geophysical-geomechanical modelling to provide near-real-time estimates of slope stability to aid forecasting of landslide events. Our approach is illustrated with results from a range of field sites located on natural and engineered slopes. We conclude that the spatially rich subsurface information provided by geophysical monitoring can make a substantial contribution to landslide EWS and can provide an improved understanding of the condition of unstable slopes.
Key controls of water vapour isotopes during oceanic evaporation and their global impact
Authors: Werner Martin , Bonne Jean-Louis , Cauquoin Alexandre , Steen-Larsen Hans Christian
Published: March 2020

Stable water isotopes are employed as hydrological tracers to quantify the diverse implications of atmospheric moisture for climate. In a recent study based on several years of in-situ isotope measurements in water vapour of the marine boundary layer it was shown that the isotope signal during evaporation is not modulated by wind speed, contrary to the commonly used theory, but controlled by relative humidity and sea surface temperature, only (Bonne et al., 2019). In sea ice covered regions, the sublimation of deposited snow on sea ice was found as another key process controlling the local water vapour isotopic composition. Here, we evaluate how these new findings will impact the stable water isotope signal both in vapour and precipitation on a global scale. For this purpose, the newly suggested parametrisations are included in two versions of the isotope-enabled atmospheric model ECHAM-wiso (Werner et al., 2016; Cauquoin et al., 2019) and a set of simulations is performed to disentangle the effects of the various controlling factors. Model results are evaluated against a compilation of short-term measurements of the isotopic composition in the marine boundary layer (Benetti et al., 2017), as well as data sets from several coastal stations (Steen-Larsen et al., 2014; 2015; 2017). In addition, the implications of the suggested parameterization changes for the interpretation of various isotope records in paleo-records will be discussed.
Convection-permitting present-day climatological simulation with WRF over Bavaria
Authors: Collier Emily , Mölg Thomas
Published: March 2020

Climate impact assessments require information about climate change at regional and ideally local scales. Traditionally, this information has been obtained using statistical methods, precluding the linkage of local climate changes to large-scale drivers in a process-based way. As part of recent efforts to investigate the impact of climate change on forest ecosystems in Bavaria, Germany, within the BayTreeNet project, we developed a high-resolution atmospheric modelling dataset, BAYWRF, for the region of Bavaria over the thirty-year period of September 1987 to August 2018. The open-source community-developed atmospheric model employed in this study, WRF, was configured with two nested domains of 7.5- and 1.5-km grid spacing centered over Bavaria and forced at the outer lateral boundaries by ERA5 reanalysis data. Based on a shorter evaluation period of September 2017 to August 2018, we evaluate two aspects of the simulations: (i) we investigate the influence of using grid-analysis nudging; and (ii) we assess model biases compared with an extensive observational data at both two-hourly and daily mean temporal resolutions. Then, we present a brief overview of the full dataset, which will provide a unique and valuable tool for investigating climate change in Bavaria with high interdisciplinary relevance. Minimally subsetted data from the finest resolution WRF domain are available for download at daily temporal resolution from a public repository at the Open Science Foundation.
Farmers see where the satellite is blind – using citizen science to fill satellite-derived vegetation data gaps
Authors: Ahmed Shakir , Friesen Jan
Published: March 2020

Satellite data for West Africa still struggle with local climate and farming practices. Despite the increasing data frequency, the rainy season in West Africa features such a dense cloud cover that many satellites cannot provide cloud free images. In addition, many farmers practice intercropping, where a single plot can be used to grow different crops such as maize and beans or even feature trees. Although the spatial resolution of satellites is ever increasing, this very small-scale intercropping still poses challenges for satellite data analysis. Yet, spatial data on vegetation status and distribution is required for running crop models.

Within the EU project TWIGA we therefore developed a smartphone app that allows farmers to collect vegetation data where it matters – on their plot!

Based on field trial that started in August 2019 we present vegetation metrics derived from smartphone photos as well as auxiliary data collected by test users in Ghana. The vegetation metrics are further combined with Sentinel 2A NDVI timeseries and fill a cloud cover caused data gap during the peak growing season.
Chance for glacially-conditioned sediment to persist within glacial overdeepenings through multiple glacial cycles
Authors: Antoniazza Gilles , Lane Stuart N.
Published: March 2020

Glaciers are major agents of landscape erosion. By their erosive power, glaciers are also considered as a sediment production “factory”. During glacial cycles, glacially-conditioned sediment is either transported by the flowing ice and the meltwaters towards terminal distal sinks (e.g. oceans), or stored for shorter or longer periods of time inland. In terms of the long-term disposal of radioactive waste (at timescales of 1 Ma) in areas affected by glaciations, scenarios for the potential of excavation of repositories by glaciers have to be calculated, so as the chance for dispersion of contaminated sediment into the environment. The question as to whether glacially-conditioned sediment contaminated by radioactive waste will be stored inland or dispersed across larger scales towards terminal sinks is therefore of great importance, and glacial overdeepenings are considered as one of the best candidates to store sediment through multiple glacial cycles.

This question of persistence of glacially-conditioned sediment within glacial overdeepenings through multiple phases of glacier advance and retreat has been investigated through a literature review. The study focuses on the Plateau of Northern Switzerland, an area that has been subject to glaciations and which is characterized by many glacial overdeepenings. Results of the literature review show that under some circumstances, glacially-conditioned sediment could persist within glacial overdeepenings across the Plateau of Northern Switzerland during multiple glacial cycles. In the meantime, the conditions required for persistence, as well as the proportions of sediment stored as compared to the sediment transferred to terminal sinks, are much less clear.
Evaluation of Clouds in the E3SM Atmosphere Model with Satellite Simulators
Authors: Zhang Yuying , Xie Shaocheng , Lin Wuyin , Klein Stephen A. , Zelinka Mark , Ma Po-Lun , Rasch Philip J.
Published: March 2020

This study systematically evaluates clouds simulated by the Energy Exascale Earth System Model (E3SM) Atmosphere Model version one (EAMv1) against satellite cloud observations. The simulator package, COSP, is used to facilitate a meaningful “apples-to-apples” comparison between model and observation by considering the different definitions of geophysical quantities among models and observations and the limitations/features of the observing process. EAMv1 is configured at two horizontal resolutions (1º and 0.25º) and one vertical resolution of 72 layers for different scientific applications. To provide a more complete picture of the model performance in simulating clouds and insights into modeled cloud biases, the evaluation is performed by utilizing unique features of individual instrument contained in COSP in observing different aspects of clouds.

 

Both low (1deg) and high (0.25deg) resolution EAMv1 configurations generally underestimat clouds in low and midlatitudes and overestimate clouds in the Arctic although the error is smaller in the high-resolution model. The underestimate of clouds is due to the underestimate of optically thin to intermediate clouds, as EAMv1 generally overestimates optically intermediate to thick clouds. Other model errors include the largely under-predicted marine stratocumulus along the coasts and high clouds over the tropical deep convection regions. The underestimate of thin clouds results in too much LW radiation being emitted to space and too little SW radiation being reflected back to space while the overestimate of optically intermediate and thick clouds leads to too little LW radiation being emitted to space and too much SW radiation being reflected back to space. EAMv1 shows better skill in reproducing the observed distribution of clouds and their properties and has smaller radiatively relevant errors in the distribution of clouds than most of the CFMIP1 and CFMIP2 models. It produces more supercooled liquid cloud fraction than CAM5 and most CMIP5 models primarily due to a new ice nucleation scheme and secondarily due to a reduction of the ice deposition growth rate.
Spatial structure, temporal variability, and dynamical features of small river plumes observed by aerial drones
Authors: Osadchiev Alexander , Barymova Alexandra
Published: March 2020

We use optical imagery and video of ocean surface acquired from aerial drones (quadcopters) to study small river plumes formed in the northeastern part of the Black Sea. Quadcopters can continuously observe small river plumes with high spatial resolution from relatively low altitude. It provides unprecedented ability to study spatial structure of small river plumes, detect and measure their temporal variability, register various dynamical features of these plumes. In this work we describe and analyze strongly inhomogeneous structure of small river plumes manifested by complex and dynamically active internal frontal zones; undulate form of sharp front between small river plume and ambient sea and energetic lateral mixing across this front caused by frontal baroclinic instability; internal waves generated by river discharge near a river estuary and propagating within inner part of a plume; internal waves generated by vortex circulation of a river plume and propagating within outer part of a plume. The issues reported in this study remained mainly unaddressed before due to low spatial and/or temporal resolution of in situ measurements and satellite imagery used in previous related studies. We show that usage of aerial drones, first, strongly enhance in situ and satellite observations of structure and variability of small plumes, second, provides ability to perform accurate, continuous, and high-resolution measurements of their spatial characteristics and current velocity fields and, finally, significantly improves organization of operational field measurements. As a result, aerial drones are effective tools to obtain new qualitative insights and quantitative assessments of structure, variability, and dynamics of small river plumes.
UAV thermal images to support the study of the expansion and contraction dynamics of river networks: a preliminary methodological approach
Authors: Micieli Massimo , Botter Gianluca , Mendicino Giuseppe , Senatore Alfonso
Published: March 2020

River networks are dynamic entities, periodically subject to expansion and contraction processes due to natural hydrological and climatic fluctuations. The ERC project "DyNET: Dynamical River Networks" aims at providing a systematic and quantitative description of such processes. The experimental activities are focused on the mapping at the basin scale of the active (i.e., characterized by flowing water) portion of the river network with the aid of drones, satellite images and field surveys, for the collection of data useful to the modelling of evolutionary processes and the development of theories to be extended on a regional scale. The use of UAVs (Unmanned Air Vehicles) specifically concerns the observation of the space-time evolution of processes, allowing to monitor wide areas and identify the presence/absence of flowing water in the river network with the help of infrared (IR) thermal imaging cameras.

The contribution discusses the effectiveness of UAVs for river networks dynamics monitoring in the Turbolo creek network (Calabria, southern Italy). Specifically, an experimental method is described that identifies and extrapolates from thermal images the pixels representing the active river network. The method is defined based on multiple acquisitions of thermal IR images on some channelized sites in different periods of the year, weather conditions, daytimes and flight altitudes. Several surveys were carried out in autumn, winter and spring seasons, with variable cloud conditions, always repeating the same flight plan, at three different altitudes and at three different times for each day of analysis. During the experiments, air temperature data were recorded by a weather station near the test area, as well as the water temperature values ​​in a small control area in the river bed, with the ascertained presence of water, monitored by the UAV. The thermal images were analyzed on GIS software, extrapolating the pixels falling within a range of values defined from the control area. The "water pixels" thus obtained allowed, through appropriate post-processing, to reconstruct the active river network even in areas not accessible by land. The methodology developed allows defining, for different periods of the year and weather conditions, optimal altitudes and flight times to accurately identify the expansion/contraction dynamics of river networks.
Multi-scale Atmospheric CO2 Variabilities over Southern Africa
Authors: Thande Boipelo B , Mengistu Tsidu Gizaw , Getachew Mengistu Anteneh
Published: March 2020

Carbon sinks play an important role in absorbing almost half of the CO2 emissions emanating from anthropogenic activities. However, regional contributions of atmospheric CO2 are not well known in Southern Africa. This is partly attributed to a shortage of in-situ data, data gaps, and limitation in the theory in modeling atmospheric CO2 dynamics. The shortage of in-situ observations and poor model skills have created a need for assimilation of observations into models to assess the variability of atmospheric levels in near real-time globally. In this study, we investigated the variabilities of XCO2 at multi-temporal scales based on reanalysis data from the carbon tracker (CT) assimilation model over Southern Africa from the year 2000 to 2016. The ensemble empirical mode decomposition (EEMD) statistical technique was used to decompose the CO2 time series into signals with different periodicities. The results demonstrate that the different component signals are driven by atmospheric, surface and oceanic forcings (e.g., rainfall, temperature, soil moisture, and SST).
Jupiter atmosphere in the infrared
Authors: Mura Alessandro , Adriani Alberto , Grassi Davide , Migliorini Alessandra , Moriconi Marisa , Altieri Francesca ,   JIRAM TEAM
Published: March 2020

The Jovian InfraRed Auroral Mapper (JIRAM) on board the Juno spacecraft, is equipped with an infrared camera and a spectrometer working in the spectral range 2-5 μm. JIRAM was built to study both the infrared aurora of Jupiter and its atmosphere. The imager observations are used for studying atmospheric dynamical structures, while spectroscopic ones are used for studying atmospheric dynamical structures and for investigating the abundance of some chemical species relevant for the atmosphere’s chemistry, microphysics and dynamics, such as water, ammonia, phosphine, germane and arsine.
Since the orbit insertion, JIRAM has performed several observations of the planet from the equator to poles. Unprecedented views of the polar atmospheric structures have been acquired for the 1st time thanks to the unique orbital design of the Juno mission. Spectral measurements provided the opportunity to measure abundances of minor atmospheric species at all latitudes down to pressures of 4-5 bars.  Limb observations at the low latitudes permit to probe abundances of methane and trihydrogen cation in the stratosphere and the thermosphere of the planet. 
In the north polar region, Juno discovered, in 2016, the presence of a regular eight-cyclone structure around a single polar cyclone; in the south, one polar cyclone is encircled by five circumpolar cyclones. Now, recent observations, performed in late 2019, showed that this configuration has significantly changed: the south structure is now more similar to a hexagon, while in the north there are significant hints that the octagonal shape may have been destroyed.
Uncertainty reduction of climate model projections for hydrologic scenarios
Authors: Sonnenborg Torben O. , Pasten-Zapata Ernesto , Eberhart Theresa , Jensen Karsten Høgh
Published: March 2020

The uncertainty of projections from climate models can be significant, especially with respect to precipitation. This represents a challenge for decision makers as the spread of the climate model ensemble can be large and, even there can be no consensus on the direction of the climate change signal. This problem is carried through to impact models such as hydrological models. Here, we evaluate different approaches to reduce the uncertainty using 16 Euro-CORDEX Regional Climate Models (RCMs) that drive three different setups of the integrated and distributed MIKE-SHE hydrological model for a catchment in Denmark. Each model is calibrated against an extensive database of hydrological observations (stream discharge, hydraulic head, actual evapotranspiration, soil moisture). We evaluate the skills of the raw and bias-corrected RCMs to simulate precipitation in a historical period using sets of nine, six, five, and three metrics for nine steps. After each step, the lowest-performing model is removed from the ensemble and the standard deviation of the new ensemble is estimated. Subsequently, the uncertainty on the projected groundwater head and stream discharge are evaluated. Based on the evaluation of raw RCM simulations, the largest decrease in the uncertainty of projected discharge (5th, 50th and 95th percentiles) is obtained using the set of five metrics. When evaluating the bias-corrected RCMs, the largest uncertainty reduction in stream discharge is obtained when the set of all nine metrics is considered. Similar results are obtained for groundwater head . The reduction of initial uncertainty is almost a factor of two higher when the evaluation of models is based on bias-corrected compared to raw climate models results. This analysis gives an insight of how different approaches could decrease the uncertainty of future projections for hydrological analyses of the impact of climate change.
Indigenous soil bacteria as bioinoculants for promoting seedling growth of native plants in arid land rehabilitation
Authors: Mahado de Lima Nathali , Charlesworth James , Stewart Jana , Muñoz-Rojas Miriam
Published: March 2020

The depletion and degradation of native plant communities is a major threat to the long-term health and functionality of many ecosystems worldwide. Some of the current challenges in mine rehabilitation programs are poor recruitment and establishment of native plants. Indigenous soil bacteria, including cyanobacteria from soil biocrusts, have shown promise as bio-fertilizers as they may promote germination and enhance seedling growth of native plants in reconstructed soil profiles. In this research, we assessed the potential of bioinoculants composed by locally sourced soil bacteria from the rhizosphere and cyanobacteria from biocrusts, to promote germination and growth of native arid plants from Western Australia and New South Wales (Australia). Individual cyanobacteria species (e.g. Leptolyngbya sp, Nostoc sp. and Microcoleus sp), a cyanobacteria mix of these three species, and enrichments of soil bacteria from the rhizosphere were considered as inoculum for seed bio-priming. Overall, our results showed that lower concentrations of cyanobacteria inoculants (1 g l-1) are more effective for promoting seedling growth than highly concentrated inoculum (5 g l-1). The effects of the cyanobacterial/bacterial inoculants were specific to each plant species. However, biopriming seeds with soil bacteria and the cyanobacteria mix resulted in three times larger roots in hummock grasses (e.g. Triodia epactia) compared to the control treatment. We also identified the bio-active components or metabolites produced by targeted cyanobacteria species through GC/MS analyses. Our results showed that some of the cyanobacterial inoculants produced substances chemically like plant hormones such as auxins, i.e. indole-3-acetic acid. The positive effects of the native soil bacteria and cyanobacteria inoculants on native plants could be related to their ability of promoting nutrient bioavailability, improving stress resistance, protection against other microbes, and production of substances that may act as hormones. The findings of this research can allow selecting the most effective bio-active inoculants for application in seed-based land rehabilitation programs.
Reactive Transport Simulations of Groundwater-derived Nutrients in a Sandy Beach in Daya Bay, China
Authors: Hu Wenli , Li Hailong , Xiao Kai
Published: March 2020

Submarine groundwater discharge (SGD) can be a significant terrestrial input of nutrients to the coastal ocean. The mixing between nearshore groundwater and seawater in coastal aquifers modifies the chemical composition of the water prior to discharge. Agricultural, aquaculture and leaky urban sewers may elevate the land-derived contaminates in the near-shore areas. The nutrient structure of Daya Bay has been strongly changed with the economic and urban development. In this study, the spatial distribution of nutrients (e.g. NO3-, NH4+, PO43-, SO42-, S2-), groundwater salinity and level were systematically investigated along an intertidal beach transect. Two-dimensional variable density and saturation, and nutrient reactive transport simulations were developed using the finite-element model MARUN. Tidal and meteorological data were also collected from local weather station to correct the model boundary.  Besides, surface air evaporation and precipitation were considered in this model to better match the field observations. The results showed that the distribution pattern of nutrients both of field observation and simulation was similar to that of salinity. For example, the concentration of NO3--N from the landward side towards the seaward side of the beach decreased and then increased, presenting an upper NO3--N plume, lower location NO3--N saltwater wedge and NO3--N discharge tube. It can approximately correspond to the upper salt plume, classical salt wedge and freshwater discharge tube. In stead of using flow velocity or simple attenuation constant to calculate the nutrient fluxes, this study used complex coupled solute reaction transport to improve the computational accuracy.
Acoustic Monitoring of Anomalous Stressed Zones, Determination of their Positions, Surfaces, Evaluation of Catastrophic Risk.
Authors: Hachay Olga , Khachay Oleg
Published: March 2020

Self-organization is not a universal property of matter, it exists under certain internal and external conditions and this is not associated with a special class of substances. The study of the morphology and dynamics of migration of anomalous zones associated with increased stresses is of particular importance in the development of deep deposits, complicated by dynamic phenomena in the form of mountain impacts. An important tool for this study is geophysical exploration. To describe the geological environment in the form of an array of rocks with its natural and technogenic heterogeneity, one should use its more adequate description, which is a discrete model of the medium in the form of a piecewise inhomogeneous block medium with embedded heterogeneities of a lower rank than the block size. This nesting can be traced several times, i.e. changing the scale of the research, we see that heterogeneities of a lower rank now appear in the form of blocks for heterogeneities of the next rank. A simple averaging of the measured geophysical parameters can lead to distorted ideas about the structure of the medium and its evolution. We have analyzed the morphology of the structural features of disintegration zones before a strong dynamic phenomenon. The introduction of the proposed integrated passive and active geophysical monitoring into the mining system, aimed at studying the transient processes of the redistribution of stress-strain and phase states, can help prevent catastrophic dynamic manifestations during the development of deep-seated deposits. Active geophysical monitoring methods should be tuned to a model of a hierarchical heterogeneous environment. Iterative algorithms for 2-D modeling and interpretation for sound diffraction and a linearly polarized transversal elastic wave on the inclusion with a hierarchical elastic structure located in the J-th layer of the N-layer elastic medium are constructed. The case is considered when the inclusion density of each rank coincides with the density of the containing layer, and the elastic parameters of inclusion of each rank differ from the elastic parameters of the containing layer.
Impacts of engineering baffles on the hyporheic exchange in a straight channel with floodplain
Authors: Huang Peng , Chui Ting Fong May
Published: March 2020

The hyporheic zone (HZ) is the region of saturated sediment surrounding a stream which connects surface water and groundwater flow. The overlying water with dissolved matters infiltrates into the HZ, stays there for some time and interacts with groundwater, and exfiltrates out of the HZ, resulting in hyporheic exchanges (HEs). The HEs support physicochemical and biological reactions that are essential to river ecosystem functions. In recent decades, more and more stream restoration projects involve the recovery of HE, however, effective guidance in restoring HE is still missing. Therefore, this study aims to examine the effectiveness of different engineering baffle designs in restoring HZ in a straight channel with floodplain. Both flume and numerical models coupling stream and groundwater flow were built. The flume model was built in a recirculating box to simulate different hydrological conditions (e.g., streamflow and groundwater flow) and baffle designs (e.g., baffle amplitude, interval). Tracer experiments were performed, and results were used to quantify the impacts of baffles designs on the HE fluxes. For the numerical models, the surface flow was simulated by solving Reynold-average Navier-Stokes (RANS) equations in two phases using volume of fluid method (VoF) in Fluent, while the groundwater flow was simulated by solving Richard’s equation in COMSOL. The numerical models were calibrated with experiments, and could output the flux, scale and median residence time (MRT) of the HE. For fixed baffle interval of four times the stream width, the flux and scale of HE peaked at baffle amplitude of around one third of stream width, while the MRT increased with increasing amplitude. For fixed baffle amplitude of one third of the stream width, the flux of HE peaked at baffle interval of around four times the stream width, the scale of HE was positively correlated to interval while the MTR had the lowest value at the interval of around two times the stream width. The results of this study directly benefit the development of practical baffle designs of river restoration.  The coupled models developed are also generally applicable to investigate the efficiency of different stream rehabilitation designs in restoring HZ.
Mathematical Modeling Algorithms for Obtaining New Materials with Desired Properties Using Nano-hierarchical Structures.
Authors: Khachay Oleg Yu. , Khachay Andrey Yu. , Hachay Olga
Published: March 2020

In the enormous and still poorly mastered gap between the macro level, where the well-developed continuum theories of continuous media and engineering methods of calculation and design operate, and the atomic, subordinate to the laws of quantum mechanics, there is an extensive meso-hierarchical level of the structure of matter. At this level unprecedented previously products and technologies can be artificially created. Nano technology is a qualitatively new strategy in technology: it creates objects in exactly the opposite way - large objects are created from small ones [1]. We have developed a new method for modeling acoustic monitoring of a layered-block elastic medium with several inclusions of various physical and mechanical hierarchical structures [2]. An iterative process is developed for solving the direct problem for the case of three hierarchical inclusions of l, m, s-th ranks based on the use of 2D integro-differential equations. The degree of hierarchy of inclusions is determined by the values â€‹â€‹of their ranks, which can be different while the first rank is associated with the atomic structure, the following ranks are associated with increasing geometric dimensions, which contain inclusions of lower ranks and sizes. Hierarchical inclusions are located in different layers one above the other: the upper one is abnormally stressed, the second is abnormally elastic and the third is abnormally dense. The degree of filling with inclusions of each rank for all three hierarchical inclusions is different. Modeling is carried out from smaller sizes to large inclusions; as a result, it becomes possible to determine the necessary parameters of the formed material from acoustic monitoring data.
References
[1] Nanotechnology in the coming decade. Forecast of the direction of research. (2002). World, Moscow - 292 p.
[2] Hachay, O. A., Khachay, A. Yu. and Khachay O. Yu. (2018). Modeling algorithm of acoustic waves penetrating through a medium with composite hierarchical inclusions.// AIP Conference Proceedings 2053, 030023; https://doi.org/10.1063/1.5084384.
Composite nature of Eco-Hydro-Geological (EHG) stability of slopes
Authors: Dias Athauda Arachchige Virajh , Tennakoon Tennakoon Mudiyanselage Anurudha , Katuwala Nimesha
Published: March 2020

Nature always educates us to explore more scientific meaning of surrounding stability of the earth. Rain triggered landslides are common in many terrains and cost for such remediation is usually high in drainage improvement. In many instances, ground water recharge, stagnation of water within soil, rock-soil interface saturations, influence of artesian water pressures, subsurface saturation due to geological complexity and many more hydro-geological regiments are responsible for landslides. However, water is the major component of ecological stability of mountain slopes which contains soil, rock, water, flora & fauna. It deals with all natural and man-made stresses from the grass root level until long term stability of the slope or slope failure event. Some large natural reservations developed as control measures against slope erosion are commonly visible in hill country slope management in Sri Lanka, dating back to year 1800. The hill country area is generally subjected to very heavy rainfall of 4000mm to 6000mm annually. The objective of this paper is to report on the progress of development techniques and studies of natural slope instabilities in saturated and unsaturated soils in order to improve our understanding of such phenomena within multiphase environments. Observations are naturally site specific. The study is to assess the impact of deviation of first principal of ecological stability during slope stability designs, understanding capacity of draining water pathways within heterogeneous regolith soils under vegetative complexity and predicting the hydrological exchange between a potentially unstable slopes and its surroundings. An approach of site specific investigations, incorporation of principal mechanism of eco-hydro-geological(EHG) techniques and isolation methods for stability will be discussed.

 
Creating an interdisciplinary environment for training early career scientists in natural hazards
Authors: Mård Johanna , Di Baldassarre Giuliano
Published: March 2020

Climate change, globalization, urbanization and increased interconnectedness between physical, human and technical systems pose major challenges to disaster risk reduction, and natural hazards and disaster research. This calls for novel scientific approaches and new data collections between the natural hazards paradigm and the vulnerability paradigm. Such interdisciplinary problem-solving approaches requires collaboration between multiple disciplines, which also increases the need to introduce interdisciplinary curriculum into higher education within natural hazard research. But, how can we construct a course of study that involve students to adopt interdisciplinary practices and interact across disciplines? The Centre of Natural Hazards and Disaster Science (CNDS) in Sweden, is an interdisciplinary research centre that gathers earth-, engineering- and social scientists to work on understanding coupled human-nature systems and reciprocal feedback mechanisms between natural hazards and sociotechnical vulnerability. The centre also has a strong focus on training early career scientists in interdisciplinary natural hazards research, both through its research school and its international summer school for PhD students. Here we share our experience in training the next generation of early career scientists in the nexus of natural hazards and sociotechnical vulnerability, and present the challenges and opportunities of teaching natural hazards in an interdisciplinary setting.
Towards experimentally-based environmental flows for infrastructure management in high-altitude tropical streams
Authors: Rosero-Lopez Daniela
Published: March 2020

Thresholds from flow–benthic fauna relationships in the light of data-scarce hydrosystems constitute an advance in implementing sustainable principles for water infrastructure management. To quantify thresholds the limits to the amount of water that can be withdrawn from Andean river networks before their natural functioning, biodiversity and ecosystem services become degraded, we conducted a whole-ecosystem experimental flow alteration. We reduced flow in the reach of a stream above a water intake from the supply system for the city of Quito, Ecuador. During the low-flow season, we diverted water using a system of weirs to accommodate streamflow in complementary percent (i.e., 90% flow deviation and 10% flow left in the stream). We performed seven reductions and kept them for seven days, during that time we sampled benthic algae chlorophyll-a concentration, flow, temperature, conductivity, light, and measured stream morphology. Our preliminary results indicate a high variability of ecological and physical responses to hydrological alterations in high-altitude tropical streams. A reduction to minimum flow similar to conditions observed for low-flows caused significant changes in stream morphology, and reductions above this threshold evidenced changes in the relative presence of major benthic algae groups.
Experimental Study Of Phase Relations In The Ca-Ongonite From Ary-Bulak Massive (Transbaykal Region, Russia) at 700–800 °C
Authors: Novikova Anna , Alferyeva Yana
Published: March 2020

An experimental study of three examples of the sub-volcanic body of Ary-Bulak ongonite was carried out to determine the composition of the liquidus phases and the order of crystallization of minerals. Phase relations in the samples of porphyritic ongonites (1), porphyritic ongonites with a high content of Ca and F (2)  and aphyric rocks with a high content of Ca and F (3) were studied at temperatures of 700–800 °C, a pressure of 1 kbar in Ni-NiO and Mt– Hem buffer conditions.

Rock samples have specific petrochemical aspects. In this series of rocks from (1) to (3), the general tendency is directed towards a decrease in the content of alkalis and silicon and an increase in the content of F and Ca.

Liquidus is achieved for porphyritic and aphyric ongonites with a high content of Ca and F. The liquidus phases for them are fluorite, topaz and plagioclase. Crystallization of porphyry ongonites begins at a temperature below 700 ° C.

The phase relationship and composition of the liquidus phases are independent of oxygen fugacity.
Benefits of Cross-Border Cooperation for Achieving Water-Energy-Land Sustainable Development Goals in the Indus Basin
Authors: Vinca Adriano , Parkinson Simon , Riahi Keywan
Published: March 2020

The Indus Basin, a densely irrigated area home to about 300-million people, has expected growing demands for water, energy and food in the coming decades.  With no abundant surface water left in the basin and accelerating use of groundwater, long-term strategic and integrated management of water and its interlinked sectors (water-energy-land) is fundamental for the sustainable development of the region. Cooperation among riparian countries is an alternative to current situation that could help achieving water-energy-land related Sustainable Development Goals, maximizing socio-environmental benefits and minimizing costs. We show a scenario-based analysis using numerical models (The Nexus Solution Tool) where we link local issues and policies to the Sustainable Development Goals, showing magnitude and geographical location of required investments to meet SDG and the associated impacts. Finally, we discuss the barriers to cross-border cooperation and explore cases of partial cooperation, which confirms significant environmental and economic benefits.
Hydrothermal activity in a lava dome detected by combined seismic and muon monitoring
Authors: Rosas-Carbajal Marina , Le Gonidec Yves , Gibert Dominique , de Bremond d'Ars Jean , Ianigro Jean-Christophe , Marteau Jacques
Published: March 2020

Characterizing volcano-hydrothermal activity is crucial for understanding the dynamics of volcanos and the relation between surface observations and deep magmatic activity. It may be also relevant for detecting precursors to magmatic and phreatic eruptions. Traditional monitoring tools such as seismicity and deformation are not always sensitive to hydrothermal activity, therefore it is important to explore new tools that can provide complementary information about the system.

Muon imaging is increasingly used as a novel tool to complement standard geophysical methods in volcanology, allowing to image large volumes of a geological body from a single observation point. Continuous measurements of the muon flux enable to infer density changes in the system. In volcanic hydrothermal systems, this approach helps to characterize processes of steam formation, condensation, water infiltration and storage. Here we present the results of a combined study in the La Soufrière de Guadeloupe volcano (West Indies, France) where continuous measurements of muon tomography were acquired simultaneously to seismic noise. The combination of these two methods helps to characterize a short-term, shallow hydrothermal event, its localization, and the involved volumes in the volcano. The deployment of networks of various sensors including temperature probes, seismic antennas and cosmic muon telescopes around volcanoes could valuably contribute to detect precursors to more hazardous hydrothermal events.
First studies of mesospheric momentum flux and wind fields using the SIMONe system over Patagonia
Authors: Conte Fede , Chau Jorge , Harding Brian , Latteck Ralph , Salvador Jacobo
Published: March 2020

During September of 2019, a state-of-the-art multistatic meteor radar system called SIMONe (Spread Spectrum Interferometric Multistatic meteor radar Observing Network) was installed in southern Patagonia, Argentina. Its main goal being the study of mesospheric waves in one of the (theoretically predicted) most dynamically active regions of the world. SIMONe Patagonia consists of 5 linearly polarized Yagi antennas in a pentagon configuration on transmission, and 5 dual-polarization single Yagi antennas on reception, situated between 30 and 270 km from the transmitters, which locate at 49.6° S. Combining measurements from the 5 links allows for more accurate estimations of mean winds and horizontal momentum flux for altitudes between 75 and 105 km. Furthermore, given the significantly higher amount of meteor detections, one can determine wind fields within the limits of the illuminated volume every 1 hour and 1 km in time and height, respectively. Preliminary results indicate a dominant semidiurnal oscillation in both the zonal and meridional wind components, as well as an enhanced and sustained (in time) gravity wave activity, especially above 90 km of altitude. In addition, momentum flux analysis reveals that the gravity wave activity is stronger than in other parts of the Southern Hemisphere, confirming that Patagonia is indeed a very active region at mesospheric heights.  
Using ATom observations and models to understand what precursors drive NPF in the remote free troposphere
Authors: Kupc Agnieszka , Williamson Christina , Hodshire Anna L. , Pierce Jeffrey R. , Kazil Jan , Ray Eric , Froyd Karl , Rollins Andrew , Richardson Mathews , Weinzierl Bernadett , Dollner Maximilian , Erdesz Frank , Bui T. Paul , Brock Charles A.
Published: March 2020

Current estimates suggest that globally, about one third of low-level cloud condensation nuclei (CCN) originate from new particle formation (NPF) in the free troposphere. However, the exact mechanisms of how these new particles form and grow to CCN sizes are not yet well quantified. We investigate the formation of new particles and their initial growth in the remote marine atmosphere over the Pacific and Atlantic basins (~80 °N to ~86 °S using (1) gas-phase and size distribution measurements (0.003-4.8 µm) from the airborne-based NASA Atmospheric Tomography global survey (ATom; 2016-2018), (2) back trajectory data, and (3) two aerosol microphysics box models.

In the ATom observations, newly formed particles were ubiquitous at high altitudes throughout broad regions of the tropics and subtropics under low condensation sink conditions and were associated with upwelling in convective clouds. This pattern was observed over four seasons and both ocean basins.

In this study, we explore processes that govern NPF and growth in the tropical and subtropical free troposphere, discuss similarities and differences in NPF over both ocean basins, use box models to examine which nucleation schemes (e.g. binary, ternary, or charged) best explain the observations, and evaluate whether sulfuric acid precursors alone can explain the NPF and the initial particle growth. Comparing aerosol size distribution measurements with box model simulations shows that none of the NPF schemes commonly used in global models are consistent with observations, regardless of precursor concentrations. Newer schemes that incorporate organic compounds as nucleating or growth agents can plausibly replicate the observed size distributions. We conclude that organic precursor species may be particularly important in NPF in the tropical upper troposphere, even above marine regions.
Reconciling global projections of precipitation with CMIP6 and CMIP5 multi-model trends
Authors: Trancoso Ralph , Syktus Jozef
Published: March 2020

Changing precipitation patterns due to climate change is a critical concern affecting society and the environment. Projected changes in global seasonal precipitation are largely heterogeneous in space, time, magnitude and direction. Therefore, reconciling projected future precipitation is pivotal for climate change science and adaptation and mitigation schemes.

This research contributes to disentangle future precipitation uncertainty globally by exploring long-term trends in projected seasonal precipitation of 33 CMIP5 and 16 CMIP6 models for the period 1980-2100. We first estimate trend slopes and significance in long-term future seasonal precipitation using the Sen-Slope and Mann-Kendall tests and constrain trends with at least 10% of cumulative changes over the 120-year period. Then, we assess convergence in the direction of trends across seasons. We highlight the world’s jurisdictions with consistent drying and wetting patterns as well as the seasonal dominance of precipitation trends.

A consistent drying pattern – where at least 78% of GCMs have decreasing precipitation trends – was observed in Central America, South and North Africa, South Europe, Southern USA and Southern South America. Unlike, a strong convergence in projected long-term wetness – where at least 78% of GCMs have increasing precipitation trends – was observed across most of Asia, Central Africa, Northern Europe, Canada, Northern US and South Brazil and surrounds.

Results show convergence in direction of seasonal precipitation trends revealing the world’s jurisdictions more likely to experience changes in future precipitation patterns. The approach is promisor to summarize trends in seasonal time-series from multiple GCMs and better constrain wetting and drying precipitation patterns. This study provides meaningful insights to inform water resource management and climate change adaptation globally.
Northern Sourced Water dominated the Atlantic Ocean during the Last Glacial Maximum
Authors: Pöppelmeier Frerk , Blaser Patrick , Gutjahr Marcus , Jaccard Samuel , Frank Martin , Max Lars , Lippold Jörg
Published: March 2020

Increased carbon sequestration in the ocean subsurface is commonly assumed to have been one of the main causes responsible for lower glacial atmospheric CO2 concentrations. This carbon must have been stored away from the atmosphere for thousands of years, yet the water mass structure accommodating such increased carbon storage continues to be debated. Here we present new sediment derived bottom water neodymium isotope data that allow fingerprinting of water masses and their mixtures and provide a more complete picture of the Atlantic overturning circulation geometry during the Last Glacial Maximums. These results suggest that the vertical and meridional structure of the Atlantic deep water mass distribution only experienced minor changes since the last ice age. In particular, we find no compelling evidence supporting glacial southern sourced water substantially expanding to shallower depths and farther into the northern hemisphere than today, which has been inferred from stable carbon isotope reconstructions. We argue that depleted δ13C values observed in the deep Northwest Atlantic do not necessarily indicate the presence of southern sourced water. Instead, these values may represent a northern sourced water mass with lower than modern preformed δ13C values that were further modified downstream by increased sequestration of remineralized carbon, facilitated by a more sluggish glacial deep circulation. If proven to be correct, the glacial water mass structure inferred from Nd isotopes has profound implications on our understanding of the deep ocean carbon storage during the Last Glacial Maximum.