bluuebunny/crossref_metadata_2025 huggingface dataset:
Pupil activities for teaching about water management
Authors: Mendes Adão , Oliveira João
Published: March 2020

Water is the most necessary natural resource for life on earth, including humans. Of all the water on earth, most is not usable by humans, either because of its physical and chemical characteristics, or because it is difficult to obtain. Examples to aid pupil understanding of different elements of water management include the following.

1. The differences between dams and salinas
Humans try to conserve water, given its importance, both in natural reservoirs and in built reservoirs, as in the example of dams. Dams therefore have different characteristics from salinas where humans try to evaporate water in large quantities. This difference can be demonstrated by dissolving the same amount of salt in two containers in the same amount of deionized water (250 ml) until near saturation. Pour water from one of the containers into a 600 ml glass beaker. Pour water from the other container into a large tray. Mark the upper limit of water in each container with a marker. Put both containers into the oven or warm on a hot plate for 24 hours at 50°C.  The pupils then observe and explain the results in the context of dams and salinas.
Comparing GRACE-FO Mascon Solutions Computed Using Range-Rate vs Range-Acceleration Data from K-Band Ranging (KBR) and Laser Ranging Interferometer (LRI)
Authors: Save Himanshu , Bettadpur Srinivas , Poole Steven , Pie Nadege , Nagel Peter
Published: March 2020

The GRACE Follow-On (GRACE-FO) mission, launched on May 22, 2018, is continuing the unprecedented mass anomaly time-series started by the GRACE mission. The 18 year record of global mass change fields have become indispensable to track the movement of water in the Earth System and monitor changes in the ice sheets, glaciers, surface water, ground water, sea level, ocean currents etc.

The traditional GRACE and GRACE-FO mascon solutions produced at the Center for Space Research uses the range-rate measurement from the intersatellite K-band ranging (KBR) data. In this paper we present techniques for computing alternate mascon solutions using range-acceleration measurements from the K-band ranging system. We discuss the comparison in techniques used and the results produced using SST range-rate vs range-acceleration data. GRACE-FO carries a technology demonstration of Laser Ranging Interferometer (LRI) system which offers a 10x improvement in the ranging measurement system. We discuss the comparison of the technique, parameterization and the resulting mascon solution derived using range-acceleration data from the KBR and LRI system.
Landfill investigation using geophysical methods for an improved characterization of the landfill geometry and for assessing microbiological activity
Authors: Aigner Lukas , Gallistl Jakob , Steiner Matthias , Brandstätter Christian , Fellner Johann , Flores Orozco Adrián
Published: March 2020

The release of landfill gas is responsible for approximately 3 % of the global greenhouse gas emissions. Especially a high content of organic matter in municipal solid waste (MSW) in wet areas may enhance the microbial activity and the production of landfill gas and leachate as metabolic products. Accordingly, the delineation of saturated zones and biogeochemically active and inactive areas is critical for designing adequate stabilization systems to limit the environmental impact of landfills on greenhouse gas production. Therefore, landfill investigations with high spatial resolution are critical for environmental protection. Geophysical methods are a cost-efficient possibility to obtain almost continuous information about subsurface properties at various spatial scales, which can help to identify biogeochemical active zones. Within this case study we investigate the applicability of three geophysical methods, namely (i) the electrical resistivity tomography (ERT), (ii) the induced polarization (IP) method and (iii) the transient electromagnetic (TEM) method to characterize the landfill geometry and to discriminate between biogeochemically active and inactive areas. The investigated landfill is located close to Vienna (Austria) and consists of a mixture of MSW, construction and demolition waste (CDW) and excavated soil. We conducted ERT and IP measurements along 17 profiles distributed over the area of the landfill to provide high resolution images of the subsurface down to 8 m depth. Additionally, we used transient electromagnetic measurements along selected profiles to provide information on deeper structures of the landfill as well as to evaluate the electrical conductivity obtained with ERT. Our results show that the electrical conductivity obtained by both ERT and TEM is mainly sensitive to the increase in the fluid conductivity associated to leachate production and migration. Additionally, a decrease in electrical conductivity is associated to CDW and dry MSW and can help to distinguish between different waste types. However, images of the polarization effect obtained with the IP method, expressed in terms of the phase of the complex conductivity, revealed an improved contrast to characterize variations in the architecture and biogeochemical activity of the landfill. Hence, our study demonstrates that the geophysical methods we applied are well-suited for landfill investigations permitting an improved characterization of landfill geometry and variation in waste composition. In particular, the IP method can delineate between biogeochemically active and inactive zones.
Exploring firn aquifers on the Muller Ice Shelf, Antarctica
Authors: MacDonell Shelley , Valois Remi , Fernandoy Francisco , Villar Paula , Casassa Gino , Hammann Arno , Marambio Marcelo
Published: March 2020

Over the last two decades, several ice shelves in the Antarctic Peninsula region have experienced significant volume loss or even total collapse driven by atmospheric, oceanic and hydrological processes. Of the three main drivers of ice shelf change, the role of liquid water on and within ice shelves is perhaps the least well defined, largely due to the paucity of field measurements. This study aims to characterise firn aquifers found within an ice shelf vulnerable to hydrological processes. To achieve this objective we use observations collected during two field seasons on the Müller Ice Shelf. The Müller Ice Shelf, the northernmost ice shelf on the western edge of the Antarctic Peninsula, presents a unique opportunity to accomplish our goal: both surface melt pools and subsurface refreezing are known to occur there, and the shelf straddles the -9ºC annual mean isotherm currently considered the limit of ice shelf viability. Measurements from the 2018/19 and 2019/20 field seasons include firn core stratigraphy, geophysical measurements and thermistor datasets, which when combined help to characterise the size and structure of water bodies found within the ice shelf. Whilst during the initial field campaign, no liquid water was observed at the surface, during the drilling of three firn cores liquid water was present at all sites at depths within 20 m of the surface. The prevalence of water and the characterization of the aquifers will provide a baseline for future dynamical studies using physically based models.
Steve: The optical signature of subauroral ion drifts
Authors: Archer William , Gallardo-Lacour Bea , Perry Gareth , St.-Maurice Jean-Pierre , Buchert Stephan , Donovan Eric
Published: March 2020

Little is currently known about the optical phenomenon known as Steve. The first scientific publication on the subject suggests that Steve is associated with an intense subauroral ion drift (SAID). However, additional inquiry is warranted as this suggested relationship as it is based on a single case study. Here we present eight occurrences of Steve with coincident or near‐coincident measurements from the European Space Agency's Swarm satellites and show that Steve is consistently associated with SAID. When satellite observations coincident with Steve are compared to that of typical SAID, we find the SAID associated with Steve to have above average peak ion velocities and electron temperatures, as well as extremely low plasma densities.
Joint statistical distribution of surface elevation and water velocity for irregular waves propagating over a shoal
Authors: Trulsen Karsten
Published: March 2020

In Trulsen et al. (2020) we reported that when irregular waves propagate over a shoal the extreme wave statistics of surface elevation and water velocity can be dramatically different:  The surface elevation can have a local maximum of kurtosis some distance into the shallower part of the shoal, while it relaxes to normality after the shoal.  The velocity field can have a local maximum of kurtosis after the shoal, while it is close to normality over the shallower part of the shoal.  These two fields clearly do not coincide regarding the location of increased probability of extreme waves.

Here we consider the evolution of the irregular waves over the shoal as a multivariate stochastic process, with a view to reveal the evolution of the joint statistical distribution of surface elevation and water velocity.  Higher order multivariate moments, coskewness and cokurtosis, more commonly seen in mathematical finance theory, are employed to describe the joint extreme wave statistical distribution of the elevation and the velocity.

Trulsen, K., Raustøl, A., Jorde, S. & Rye, L. B. (2020) Extreme wave statistics of longcrested irregular waves over a shoal.  J. Fluid Mech. 882, R2.
Marie Tharp’s Ongoing Legacy in Global Seabed Mapping Efforts
Authors: Ferrini Vicki , Ryan William , Carbotte Suzanne , O'Hara Suzanne
Published: March 2020

The illumination of the seafloor through Marie Tharp’s lens was instrumental in the plate tectonics revolution and fundamentally transformed our understanding of earth processes. Rather than creating traditional contour maps from isolated soundings, her work yielded physiographic diagrams based on sparse echo-sounding profiles that were complemented by stylized views based on her interpretation of the trends and texture of the seafloor. These maps showed the fabric of seafloor in ways that could not have been achieved or communicated with traditional contour plots. Despite the sparseness of the input data, Marie Tharp and Bruce Heezen’s early seafloor maps are remarkably consistent with modern bathymetric maps that are based on orders of magnitude more observations.

An important part of the legacy of Tharp’s work is codified in the evolution of bathymetric data synthesis efforts led by several of her contemporaries and successors at the Lamont-Doherty Earth Observatory (LDEO). After Tharp’s seminal work transforming bathymetric profiles into the first maps of the global seafloor, efforts were undertaken to digitize echo-sounding profiles creating new opportunities for analysis and integration as well as the development of new software tools and approaches for working with those data. In the 1980s, the availability of multibeam sonars in the academic sector ushered in a new era of mapping by extending the data coverage from profiles to swaths that revealed spatially-continuous areas of the seafloor. The Ridge Multibeam Synthesis (RMBS) Project, which began in the 1990s, built upon Tharp’s early work and sought to advance understanding of the global mid-ocean ridge system by integrating swath data from multiple ships and cruises to create detailed bathymetric grids served online via the early web. Just over a decade later, the Global Multi-Resolution Topography (GMRT) Synthesis emerged as the next generation product under the inspiration of William Haxby. GMRT shifted the focus of effort from the mid-ocean ridges to the global ocean, and presented an efficient scalable solution using a tiled approach for providing access to global bathymetric data at native resolution. GMRT continues today and includes a curated collection of bathymetry data from over 1,100 research expeditions covering more than 9% of the global ocean at 100m spatial resolution. This presentation will describe the legacy of Marie Tharp in the context of the continuity of seabed mapping work at LDEO, including the evolution of bathymetry data synthesis and integration projects and how they connect to complementary efforts in the international arena including the Nippon Foundation – GEBCO Seabed 2030 Project.
Fate of antibioresistance, pharmaceuticals and endocrine disruptors from a former municipal landfill
Authors: Le Guern Cecile , Lepinay Alexandra , Aujoulat Fabien , Capiaux Hervé , Jumas-Bilak Estelle , Lebeau Thierry , Licznar Patricia , Flahaut Bernard , Augris Pierre , Bodéré Gwenaëlle , Béchet Béatrice
Published: March 2020

Antibioresistance may develop in different contexts (e.g. hospitals, wastewater treatment plants, animal farming) through various processes. Because municipal landfills may have received medication waste coming from citizens but also from hospitals, they may represent a source of antibioresistance disseminating in the natural environment. Together with the fate of pharmaceuticals and endocrine disruptors, we studied the fate of antibioresistance from a former municipal landfill located in Nantes, France. Both municipal and hospital waste were deposited in this landfill between 1969 and 1987. The total volume of waste is around 2 million cubic meters.

We sampled leachates from the landfill, as well as groundwater upstream and downstream the landfill. Extraction (SPE or liquid/liquid) on frozen or fresh samples allowed quantifying 30 pharmaceutical molecules and 8 other emerging by LC/MSMS, UPLC/MSMS or GC/MSMS. The abundance of total cultivable communities was determined by counting on non-selective medium. Culture media used in clinical microbiology (drigalski / ceftazidime, Msuper CARBA and ESBL) were used to determine the proportion of the bacterial community that is resistant to antibiotics. Eventually, the diversity of the total communities was studied by PCR-TTGE and by 16S metabarcoding (MiSeq Illumina).

Over of the whole substances sought, 11 pharmaceutical molecules (not antibiotics), have been quantified in the leachates and 2 endocrine disruptors (bisphenol A and triclosan). Most substances were also recovered in groundwater immediately downstream the site (including carbamazepine) at concentrations ranging between 0.1 µg/L and 10 µg/L. The number of detected substances was lower a few hundred meters far from the landfill. More especially bisphenol A and diclofenac show lower concentrations ranging from 0.1 to 1 µg/L and about 0.1 µg/L respectively). Similar observations were shown for antibioresistance. The bacteria from leachates show a more important antibioresistance than in the other groundwater samples. The transfer of antibioresistant bacteria seems limited downstream the landfill, with nevertheless higher content at the immediate downstream. The natural attenuation may be explained by several processes, some being the same as for metals and PAH.
Magnetic Pulsations and Transients on Martian Surface
Authors: Chi Peter , Russell Christopher , Joy Steve , Yu Yanan , Banfield Don , Fillingim Matthew , Ma Yingjuan , Smrekar Suzanne , Banerdt William
Published: March 2020

InSight is the first Mars surface mission that includes a magnetometer, and one of the first discoveries made by the InSight FluxGate (IFG) magnetometer is the ultra-low-frequency (ULF) waves, or magnetic pulsations, on the Martian surface. By studying magnetic pulsations and transient signatures in more than six months of IFG data, we find that the morphologies of these two types of perturbations have considerable variations from their counterparts on the Earth, reflecting the fundamental differences between the magnetospheres with and without a global magnetic field. The most noticeable ULF waves are the continuous pulsations (Pc) occurring at around midnight and with wave periods of the order of 100 sec, or in the Pc 4 frequency band when the terminology of terrestrial magnetic pulsations is used. Broadband pulsations at Pc 5 frequencies (i.e., a few mHz) have also been observed. Comparisons with lander activities and InSight’s Temperature and Wind for InSight Subsystem (TWINS) data confirm that the observed magnetic pulsations are not caused by tremors of the lander. Simultaneous observations by MAVEN in the solar wind and InSight on Mars indicate that the upstream waves in front of Mars bow shock can hardly reach the dayside surface, leading to a dearth of magnetic pulsations in the daytime. In addition, solar wind discontinuities or transient events can induce noticeable surface magnetic responses only in the nightside, suggesting that the magnetic pileup region and ionosphere can effectively shield external magnetic disturbances. MAVEN observations also help identify sources of magnetic pulsations seen on the Martian surface. While the low-frequency, broad-band Pc 5 pulsations may be excited by the oscillations on the flanks of the induced magnetosphere associated with solar wind variations or the Kelvin-Helmholtz instability, there is a strong indication that the nightside Pc 4 pulsations on the surface originate from the compressional oscillations in the magnetotail. Different from the flow-generated fast mode waves in the terrestrial magnetotail, the fast mode in the Martian magnetotail could travel toward the planet without substantial coupling to the Alfvén mode. The Mars-propagating fast mode experiences little reflection from the ionosphere and can produce surface magnetic pulsations at low latitudes on the nightside. These first findings of magnetic pulsations and transients on the Martian surface not only reveal the origins and propagation of magnetic signals from the outer space but also help determine the source model for the magnetic sounding of Mars' interior.
Wildfire weather, intensity and smoke emissions of large-scale fire events in 2019
Authors: Parrington Mark , Di Giuseppe Francesca , Smith Thomas , Vitolo Claudia , Garrigues Sebastien , Wooster Martin , Zhang Tianran , Kaiser Johannes , Ades Melanie , Agusti-Panareda Anna , Barre Jerome , Bousserez Nicolas , Engelen Richard , Flemming Johannes , Inness Antje , Kipling Zak , Peuch Vincent-Henri , Vamborg Freja , Coughlan Ruth
Published: March 2020

Effective monitoring of global wildfire activity requires comprehensive knowledge of changing environmental (including atmospheric and hydrological) conditions, fuel availability and routine observations of fire locations and intensity. The European Centre for Medium-Range Weather Forecasts (ECMWF) through its operation of, and contribution to, different Copernicus Services is in a unique position to provide detailed information on the conditions leading to wildland fire activity, the evolution of wildfires, and their potential impacts, when they occur. Fire weather forecasts from the Copernicus Emergency Management Service, and surface climate anomalies from the Copernicus Climate Change Service both provide context to the environmental conditions required for wildfires to persist. Analyses based on observations of fire radiative power, along with analyses and forecasts of associated atmospheric pollutants, from the Copernicus Atmosphere Monitoring Service aid in quantifying the scale and intensity in near-real-time and the subsequent atmospheric impacts. During 2019, regions of anomalously hot and dry surface conditions in Arctic Siberia and southeast Australia experienced large-scale, long-duration wildfires which burned thousands of square kilometres with a total intensity that was significantly above the average of the previous 16 years of data in those regions. We present an overview of the evolution of fire activity in Siberia between June-August 2019, and Australia between September 2019-January 2020, based on ECMWF/Copernicus data for fire weather, climate anomalies and active fires. We will show that the different datasets, while being relatively independent, show a strong correspondence and provide a wealth of information vital to understanding global wildfires, their underlying causes and environmental impacts.
Modeling fabric development using coupled non-parametric orientation and lattice strain-energy distribution functions
Authors: Rathmann Nicholas , Grindsted Aslak , Faria Sérgio H. , Lilien David A. , Hvidberg Christine S. , Dahl-Jensen Dorthe
Published: March 2020

As polycrystalline ice undergoes ductile deformation, the c-axis fabric develops and the effective, macroscopic physical properties of ice become anisotropic. Modeling the flow of anisotropic ice therefore necessitates modeling the evolution of c-axes, too. We propose a non-parametric spectral model to account for the co-evolution of c-axis orientation distributions and stored lattice strain-energy distributions, which in principle allows any distribution shape to be represented. The coupled evolution provides the means to (statistically) model nucleation and migration recrystallization in an energy consistent way as nonuniform decay processes that depend on the accumulated cold work experienced by a given parcel of ice. The free model parameters determine the relative importance of grain rotation versus dynamic recrystallization processes given the local ice temperature, stress- and strain-rate states. We argue that the free parameters may be constrained by consulting the ice-core literature and present tentative simulations of the GRIP ice-core fabric.
Multi-instrument Observations of Ion-Neutral Coupling in the Dayside Cusp
Authors: Wild James , Billett Daniel , Hosokawa Keisuke , Grocott Adrian , Aruliah Anasuya , Ogawa Yasunobu , Taguchi Satoshi , Lester Mark
Published: March 2020

Using data from the Scanning Doppler Imager, the Super Dual Auroral Radar Network, the EISCAT Svalbard Radar and an auroral all-sky imager, we examine an instance of F-region neutral winds which have been influenced by the presence of poleward moving auroral forms near the dayside cusp region. We observe a reduction in the time taken for the ion-drag force to re-orientate the neutrals into the direction of the convective plasma (on the order of minutes), compared to before the auroral activity began. Additionally, because the ionosphere near the cusp is influenced much more readily by changes in the solar wind via dayside reconnection, we observe the neutrals responding to an interplanetary magnetic field change within minutes of it occurring. This has implications on the rate that energy is deposited into the ionosphere via Joule heating, which we show to become dampened by the neutral winds.
Geophysical characterization of inactive/active rock glaciers in the semi-arid Andes using seismic, geoelectrics and GPR
Authors: valois remi , Schafer Nicole , De Pasquale Giulia , Navarro Gonzalo , MacDonell Shelley
Published: March 2020

Rock glaciers play an important hydrological role in the semiarid Andes (SA; 27º-35ºS). They cover about three times the area of uncovered glaciers and they are an important contribution to streamflow when water is needed most, especially during dry years and in the late summer months. Their characteristics such as their extension in depth and their ice content is poorly known. Here, we present a case study of one active rock glacier and periglacial inactive geoform in Estero Derecho (~30˚S), in the upper Elqui River catchment, Chile. Three geophysical methods (ground-penetrating radar and electrical resistivity and seismic refraction tomography) were combined to detect the presence of ice and understand the internal structure of the landform. The results suggest that the combination of electrical resistivity and seismic velocity provide relevant information on ice presence and their geometry. Radargrams shows diffraction linked to boulders presence but some information regarding electromagnetic velocity could be extracted. These results strongly suggest that such landforms contain ice, are therefore important to include in future inventories and should be considered when evaluating the hydrological importance of a particular region.

 
Investigating global changes in snow dynamics and the impact on water resources
Authors: Fontrodona Bach Adrià , Larsen Joshua , Woods Ross , Schaefli Bettina , Teuling Ryan
Published: March 2020

Snow is a key component of the hydrological cycle in many regions of the world, providing a natural storage of water by accumulating snow in winter and releasing it in spring. Many ecosystems, societies and economies rely on this mechanism as a water resource. There is strong evidence in the literature that global warming leads to decreasing snowfall and snow accumulation and shifts the onset of the melt season to earlier in the year. However, little is known about how rising temperatures affect snowmelt rates and timing, and how these can have an impact on water resources for instance by changing the time and magnitude of streamflow. Some studies predict slower snowmelt rates in a warmer world, due to the onset of melt being earlier when there is less energy available for melt, but there is not yet an observation-based study showing such trends. As a first step, here we present preliminary results of observed long term trends in snowmelt rates from different climates. We use a dataset that has already shown strong decreasing signals for winter snow accumulation. Here we also present potential avenues to investigate the sensitivity of snowpacks and snowmelt regimes in different climatic settings to further rising temperatures using modeled snow dynamics. A few possibilities on how to link the snowpack dynamics to impacts in water resources are also discussed, for instance by comparing modelled dynamics to hydrological models and observations.
Analysis of 60-yr record of surface 137Cs concentrations in the global ocean
Authors: Inomata Yayoi , Aoyama Michio
Published: March 2020

We investigated spatial and temporal variations in 137Cs concentrations in the surface waters of the global ocean for the period from 1957 to 2018. In order to study the distribution of 137Cs concentrations in surface seawater, we divided the global ocean into 37 latitudinal boxes on the basis of known ocean current systems, latitudinal and longitudinal distributions of 137Cs concentrations, the distribution of global fallout, locations of nuclear reprocessing plants, fallout from the Chernobyl accident, and release from Fukushima Nuclear Power Plant accident. Based on the 0.5-y average value of 137Cs concentrations in the surface water in each box, we classified the temporal variations into four types. In the North Pacific Ocean where there was high fallout from atmospheric nuclear weapons tests, the rates of decrease in the 137Cs concentrations changed over the five decades: the rate of decrease from the 1950s to the 1970s was much faster than that after the 1970s, and the 137Cs concentrations were almost constant after the 1990s. Latitudinal differences in 137Cs concentrations in the North Pacific Ocean became small with time. After March 2011, extremely high concentrations (3.26×107 Bq/m3) were observed in the western North Pacific Ocean based on the direct release and atmospheric deposition of FNPP1-derived 137Cs. In the equatorial Pacific and Indian Oceans, the 137Cs concentrations varied within a constant range in the 1970s and 1980s, due to the advection of 137Cs from areas of high global fallout in the mid-latitudes of the North Pacific Ocean. In the eastern South Pacific and Atlantic Oceans (south of 40°S), the concentrations decreased exponentially over the six decades. In the Arctic and North Atlantic Oceans, including marginal seas, 137Cs concentrations were strongly controlled by discharge from nuclear reprocessing plants after the late 1970s. The 137Cs concentrations were rapidly decreased after the early 1980s, and advected into the Arctic Ocean. 
The averaged 137Cs concentrations in each box in the year of 1970 were 1-716 Bq/m3, and those were decreased to 0.2-28 Bq/m3 in the year of 2010. The apparent half-residence times of 137Cs in the surface waters of the global ocean from 1970 to 2010 ranged from 4.2 to 48.1 years for each box. 

(Reference)
Inomata et al. (2009) Analysis of 50-y record of surface 137Cs concentrations in the global ocean using the HAM-global database. Journal of Environmental Monitoring, DOI: 10.1039/b811421h. 

 
Thermal and chemical properties of the mantle transition zone from seismic observations
Authors: Goes Saskia , Yu Chunquan , Maguire Ross , Day Elizabeth , van der Hilst Rob , Ritsema Jeroen , Jian Jing
Published: March 2020

The mantle transition zone (MTZ), bounded by 410 and 660 discontinuities, is a key region to understand the thermal, chemical, and dynamical evolution of the mantle. Mantle dynamics is primarily thermally driven and the topography of 410 and 660 has been widely used to infer the temperature of the MTZ. However, in a number of recent studies, we have found that properties of transition-zone discontinuities may also provide insight in the distribution of compositional heterogeneity. We will present preliminary results from a global study of PP and SS precursors using a curvelet-based seismic array processing technique, where we successfully extract P660P signals, which are traditionally difficult to observe, over a wide distance range. Comparison with thermodynamic models suggests that on a global scale, amplitude trends of SS and PP precursors from both 410 and 660 are consistent with predictions from a pyrolitic mantle transition zone. We also find that global variation in MTZ thickness has a positive correlation with velocity anomalies within the MTZ. Both of them are likely controlled by thermal anomalies, consistent with mineralogical phase transitions of the olivine system. In an application of this method to data from Hawaii however, we found evidence of compositional variations, consistent with the analysis of tomographic images below a few other hotspots. Further compositional heterogeneity linked to recent subduction has been found from a receiver-function study below the US. Results thus indicate a quite well mixed background mantle with more heterogeneity in areas of recent up-and downwelling.
Assessing the probability of volume estimates initial landslide ruptures based on surface area
Authors: Jaboyedoff Michel , Meier Cedric , Marc-Henri Derron , Gerber Christian
Published: March 2020

There exist several relationships between landslide surface areas and volumes. Most of them are based on simple geometric shape such as half ellipsoid or surface prisms. Using a new inventory of 66 small and shallow landslides was created using high resolution digital elevation model in the canton of Vaud (Switzerland). The volume calculation was based on horizontal surface areas (A) and the maximum vertical depth, using both paraboloid-elliptic or half ellipsoid. The relationship between surface area – maximum vertical depth (zmax) is deduced using principal component analysis (PCA) in a log-log space, which leads to a power-law (Jaboyedoff et al., 2020). The distribution of the distances of the 66 couple of values to this line is close to a log-normal distribution. This allows to calculate the probability to overpass a volume using both paraboloid-elliptic and half ellipsoid to calculate volumes based on maximum depth zmax.

The trend of relationship is very similar to the one obtained by Guzzetti et al. (2009), but the confidence level narrower. In our case a volume can be 8 times larger between the two boundaries of the centred 95% confidence level, and for the Guzzetti et al. (2009) it reaches 38 times based on their confidence level.

This approach demonstrates that there are large uncertainties on the volume estimations. But if it is applied to coherent inventories, it can provide good approximations. As the landslide runout distance depends on the volume involved, such approach is promising for improving landslides hazard.

References

Guzzetti F., Ardizzone F., Cardinali M., Rossi M., Valigi, D. 2009. Landslide volumes and landslide mobilization rates in Umbria, central Italy. Earth and Planetary Science Letters, 279(3-4), 222-229.

Meier, C., Jaboyedoff, M., Derron, M.-H., Gerber, C., 2020. A method to assess the probability of thickness and volume estimates of small and shallow initial landslide ruptures based on surface area. Landslides. //doi.org/10.1007/s10346-020-01347-0
Mapping of sinkholes in highly urbanized areas: Queretaro, Mexico.
Authors: Hernández López Iliana Guadalupe , González Sosa Enrique , Pérez Rea María de la Luz , Carreón Freyre Dora Celia
Published: March 2020

In recent years, there have appeared sinkholes of various dimensions in urban areas in different parts of the world. This phenomenon represents a serious social, economic and environmental danger, since it causes alarm among the population, and considerable damage in the infrastructure. The sinkholes are generated mainly by two causes: karstic geology (common in calcic sedimentary rocks) or by the presence of excess water generated by cracks in the pipe water and sewage systems.

The excess of water is the most frequent case in highly urban centres, where the lack of maintenance or the age of the drainage systems, generate internal erosion and dissolution of the finest particles, producing the abrupt vertical collapse of the soil, which develops an hole in the ground. From experimental studies, the mechanism of soils that generate internal erosion; soil stratification, soil types and their hydrodynamic properties, is well known.

In Mexico, sinkholes are a very common problem in the center of the country, mainly in states like Aguascalientes, Mexico City, San Luis Potosi, State of Mexico and Queretaro. In particular, in the city of Queretaro, there have been sinkholes, which have affected the traffic and movility of this city.

Documentary analysis and mapping indicate that this type of sinkholes show a tendency to be generated in the periphery of the capital of Queretaro, because these are areas of potential urban growth, as well as exceeding the service capacity of the sewage and potable water systems, regardless of the construction process of this type of work. The results show that in 2018, at least seven significant sinkholes were generated in the urban area, while in 2019, more than 15 sinkholes, most of which have been ruled to be caused by a rupture in potable water and sewage pipes, were reported.  In this first evaluation we can observe a double increase in the appeareance of sinkholes, therefore, it is necessary to carry out constant field and experimental studies, to understand the mechanism of these phenomena that occur in highly urbanized areas.
Uncertainty in the response of sudden stratospheric warmings and stratosphere- troposphere coupling to quadrupled CO2 concentrations in CMIP6 models
Authors: Ayarzagüena Blanca , Charlton-Pérez Andrew J. , Butler Amy H. , Hitchcock Peter , Simpson Isla R. , Polvani Lorenzo M. , Butchart Neal , Gerber Edwin P. , Gray Lesley , Hassler Birgit , Lin Pu , Lott François , Manzini Elisa , Mizuta Ryo , Orbe Clara , Osprey Scott , Saint-Martin David , Sigmond Michael , Taguchi Masakazu , Volodin Evgeny ,   DynVarMIP-SSW
Published: March 2020

Major sudden stratospheric warmings (SSWs), vortex formation and final breakdown dates are key highlight points of the stratospheric polar vortex. These phenomena are relevant for stratosphere-troposphere coupling, which explains the interest in understanding their future changes. However, up to now, there is not a clear consensus on which projected changes to the polar vortex are robust, particularly in the Northern Hemisphere, possibly due to short data record or relatively moderate CO2 forcing. The new simulations performed under the Coupled Model Intercomparison Project, Phase 6, together with the long daily data requirements of the DynVarMIP project in preindustrial and quadrupled CO2 (4xCO2 ) forcing simulations provide a new opportunity to revisit this topic by overcoming the limitations mentioned above.

In this study, we analyze this new model output to document the change, if any, in the frequency of SSWs under 4xCO2 forcing. Our analysis reveals a large disagreement across the models as to the sign of this change, even though most models show a statistically significant change. The models, however, are in good agreement as to the impact of SSWs over the North Atlantic: there is no indication of a change under 4xCO2 forcing. Over the Pacific, however, the change is more uncertain. Finally, the models show robust changes to the seasonal cycle in the stratosphere. Specifically, we find a longer duration of the stratospheric polar vortex, and thus a longer season of stratosphere-troposphere coupling.
Laboratory simulation of the pancake ice influence on the wind wave interaction
Authors: Sergeev Daniil , Troitskaya Yuliya , Kandaurov Alexander
Published: March 2020

Recently, much attention has been paid to the study and numerical simulation of wind waves in the Arctic regions of the oceans. Their distinctive feature is the presence of ice cover of various types, which can significantly affect the processes of wind wave interaction, including momentum exchange. A detailed study of such processes under natural conditions is very difficult, especially for the forming ice (including pancake ice), therefore, laboratory simulation is preferable. Previously studies of the influence of floating ice on the evolution of waves that were generated by wavemakers were carried out only. In this paper we present preliminary results of studies performed on the AELOTRON circular wind wave flume of the University of Heidelberg, where the interaction of air flow with a water surface was simulated for the first time in the presence of forming ice of the pancake type. Synchronous measurements of wave characteristics were carried out using a laser wavegauge, as well as airflow velocity fields were measured with PIV-methods. Shims made of rubber with a diameter of 7 cm and a thickness of 1 cm with a density of about 0.8 kg /m3 were used as elements of artificial ice. The measurements were carried out in clean water and at three concentrations of artificial ice: maximum, 2/3 of the maximum, 1/3 of the maximum. Ice covered about half the surface at maximum concentration. The measurements were carried out in the range of equivalent wind speeds U10 from 7 to 16  m/s. The threshold character of excitation of long waves was obtained (the length is much greater than the average distance between the elements of ice). The higher the density, the higher the threshold for wind speed. According to the results of processing the velocity fields, the dependence of the aerodynamic drag coefficient on the equivalent wind speed was constructed. It is shown that the presence of ice weakly affects the momentum exchange for all concentrations and over the entire wind speed range.

Investigation was supported by Russian Found Basic Research project # 18-05-60299 Arctic.
Computational thermodynamics: towards an improved Gibbs minimization tool for geodynamic modelling
Authors: Riel Nicolas , Kaus Boris , Berlie Nicolas , Rummel Lisa , Green Eleanor
Published: March 2020

In the last decade, the development of numerical geodynamic tools helped the geoscience community to explore thermo-mechanical processes at play during plate tectonics. Yet, the high computational cost of thermodynamic calculations hampers our ability to quantify multi-phase systems in which the interplay between plate-tectonics and phase transformations leads to magmatism.  Here we use the 'igneous set' of HPx-eos (thermodynamic models for minerals and geological fluids that are based on the Holland & Powell dataset and defined in the THERMOCALC software) to calculate stable phase equilibria in the system K2O–Na2O–CaO–FeO–MgO–Al2O3–SiO2–H2O–TiO2–Fe2O3–Cr2O3 (KNCFMASHTOCr). The calculation is performed by Gibbs free energy minimization at prescribed pressure, temperature and bulk-rock composition and is achieved in two steps. First, we employ a levelling method (iterative change of base) to reduce the number of potential stable phases. Then, the composition and proportions of stable phases at equilibrium are determined using several constrained optimization methods. We explore the computational efficiency of linear programming (e.g., Simplex), Gradient-based (e.g., SLSPQ) and Hessian-based (e.g., Newton-Raphson) methods. The accuracy and performance of tested methods are compared, and applications to geodynamic modelling are discussed.
Soil amendments reduce P release from flooded soils: Incubation studies simulating snowmelt and summer flooding
Authors: Attanayake Chammi , Kumaragamage Darshani , Weerasekara Chamara , Vitharana Udaya , Dharmakeerthi Saman , Van Emily , Goltz Doug , Indraratne Srimathie
Published: March 2020

Flooding caused by snowmelt runoff in the spring and early summer and heavy rainfall in the summer could enhance P release into nearby surface water bodies causing eutrophication. Six soil amendments were tested for their effectiveness  in reducing P release from flooded-soils. Soils were collected from the flood-prone fields in the Red River Valley region in Manitoba, Canada. The tested amendments were gypsum, magnesium sulphate, alum, ferric chloride, zeolite and manganese oxides. Intact soil columns were subjected to flooding for 8 weeks at 4oC simulating the snowmelt in the spring and the early summer and at 22oC simulating flooding occurrences in the summer.  Release of soil P into soil solution and floodwater was higher at 22oC than that at 4oC. Gypsum, magnesium sulphate, alum and ferric chloride were effective in reducing the concentrations of P in the pore- and flood-water at various capacities. Ongoing research on zeolite and manganese oxide suggests that manganese oxide was more effective in reducing soluble P concentrations in soils at early days of flooding.
Evaluating Historical Impacts of Surface Reservoir Storage on Catchment Memory Across the US
Authors: Condon Laura , Steyaert Jen , Spinti Rachel
Published: March 2020

Today there are tens of thousands of storage structures in the US ranging from Hoover Dam, with a capacity more than 34 million cubic meters, to small structures less than 2 m tall.  While there exists a myriad of water management tools that capture storage operations for local to regional systems, national and global scale hydrologic models struggle to incorporate this storage. Large scale earth system simulations generally exclude management operations or rely on generic operating policies due to lack of data.  Reservoir storage capacity is much more easily obtained and can tell us about the potential for regulation of a system, but without evaluating actual operations we can’t capture the actual influence of human storage on catchment dynamics.  Here we use the National Inventory of Dams to evaluate the evolution of total storage capacity across the US over the last century. Consistent with previous work we show spatial trends in storage volume relative to streamflow and storage purpose (i.e. flood control as opposed to water supply). To quantify the actual impact of operations on hydrologic regimes though, reservoir capacity is not sufficient. Therefore, we also assemble a dataset of reservoir inflows, outflows and changes in storage focusing on large reservoirs in the western US.  Using these timeseries we can isolate the historical regulation imposed by reservoirs and their impact catchment memory. Furthermore, we compare our historical observations to generic operating policies to evaluate how well storage dynamics are captured by existing models and the potential for these tools to over or underestimate reservoir impacts.
Extending the Pegasus Portable Technology Platform to Apply to More Geophysical Monitoring Use
Authors: Townsend Bruce , Moores Andrew , Pigeon Sylvain
Published: March 2020

The new Nanometrics Pegasus now available to the scientific community provides a compelling comprehensive solution for easily and quickly deploying portable seismic stations. Use cases include RAMP, local and regional hazard monitoring, passive seismic imaging and local or regional seismicity assessments. Because the technology platform on which Pegasus Portable is based is extensible and versatile, it has the potential to address additional use cases. The benefits of the Pegasus technology would apply to new use cases: optimal SWaP (Size, Weight and Power), Modularity (the versatility permits wide choice of sensors and power to serve various situations), Ease-of-Use (workflows designed for planning-to-publishing efficiency), Complete Ready-to-Use Datasets (including automatically generated station response), and Quick (such as ultra-fast boot, rapid data download). We explore the potential extensions to Pegasus that can enable additional use cases for autonomous geophysical monitoring.

An example is large-N mixed-mode nodal deployments in which hundreds of stations are quickly deployed that can include a mix of sensor types such as broadband seismometers, geophones, microbarometers, and weather stations. A key focus for large-N campaigns is to scale efficiently. One proposed element for consideration is a cloud-based campaign planning and post-deployment auditing service in which a master plan can be readily distributed to many field operators to facilitate automatic station configuration and later reconciliation of on-the-ground actions with the master plan. 

Another compelling use case for Pegasus is ocean bottom seismometry, where technology enablers would include OBS-specific actions and workflows (managing the datalogger and its power sources without having to open marine pressure vessels, synchronizing timing to GNSS, applying time corrections to retrieved data and the like). These and other use cases and related technology extensions are discussed.
Microbial community shift under exposure of dredged sediments from a tropical eutrophic bay
Authors: Nascimento Juliana , Easson Cole , Jurelevicius Diogo , Lopes Jose , Bidone Edison , Sabadini-Santos Elisamara
Published: March 2020

Microbial communities occur in almost every habitat. To evaluate the homeostasis disruption of in situ microbiomes, dredged sediments from Guanabara Bay-Brazil (GB) were mixed with sediments outside the bay (D) in three different proportions (25%, 50% and 75%) which we called GBD25, GBD50 and GBD75. Grain size, TOC and metals -as indicators of complex contamination-; dehydrogenase (DHA) and esterases enzymes (EST) – as indicators of microbial community availability, were determined. Microbial community composition was addressed by amplifying the 16S rRNA gene for DGGE analysis and sequencing using MiSeq platform (Illumina). We applied the Quality Ratio index (QR) to the GB, D and every GBD mixture to integrate geochemical parameters with our microbiome data. QR indicated high environmental risk for GB and every GBD mixture; and low risk for D. The community shifted from aerobic to anaerobic profile, consistent with the characteristics of GB. Sample D was dominated by JTB255 marine benthic group, related to low impacted areas. Milano-WF1B-44 was the most representative of GB, often found in anaerobic and sulfur enriched environments. In GBD, the denitrifying sulfur-oxidizing bacteria, Sulfurovum, was the most representative, typically found in suboxic or anoxic niches. The canonical correspondence analysis was able to explain 60% of the community composition variation and exhibit the decrease of environmental quality as the contamination increases. Physiological and taxonomic shifts of the microbial assemblage in sediments was inferred by QR, which was suitable to determinate sediment risk. The study produced sufficient information to improve dredging plan and management.