bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymes Activity in Response to Veterinary Antibiotics in Presence of Organic (Biochar and Manure) and Mineral (Nano-Zeolite) amendment
Authors: Rashtbari Mehdi , Safari Sinegani Ali Akbar
Published: March 2020

Annually, millions of tons of antibiotics in the world are used in medicine, veterinary and agriculture, and their excessive application have negative impacts on soil microorganisms and biological processes. In the present study, the effect of releasing the mostly used antibiotic in veterinary and ameliorative impact of organic and non-organic amendments was studied in which treatments include (control (without antibiotic), gentamicin, oxytetracycline and penicillin) and different concentrations (50, 100 and 200 mg/kg dry soil) with and without organic and mineral conditioners (cow manure, biochar and nano-zeolite) on soil urease (URE) and alkaline phosphatase (ALP) enzyme activity and their resistance and resilience indices at three time periods including 1-7, 7-30 and 30-90 days during a 90-day incubation time in a split-factorial design which soil conditioners were considered as the main plots and antibiotic types and concentration were as experimental factors. Resistance (RS) and resilience (RL) indices were calculated for enzymes activity. Results showed that in control treatment (without conditioner), application of gentamicin at 200 mg/kg caused a 68.9 percent decrease in soil ALP activity compared to control (without antibiotic), while a decrease in ALP activity in tetracycline-treated soils compared to control (without conditioner), manure, biochar, and nano-zeolite was 17.5, 13.8, 17.5 and 16 percent, respectively. URE enzyme activity at 30-90-days during incubation the period had an increasing trend from 1-7 days and the highest enzyme activity was measured on the 90th day of incubation. According to results, soil enzymes responded differently to antibiotics and conditioners in soil, so that penicillin and oxytetracycline had no considerable negative impact on ALP enzyme activity, while gentamicin and oxytetracycline at all applied concentrations significantly decreased URE activity. To sum up, findings showed that application of soil conditioners could alleviate negative impacts of antibiotics in soil and could improve resistance and resilience indexes of soil enzymes activities in soil.
Simulating extreme sea levels at the Baltic Sea coast from synthetic cyclones
Authors: Särkkä Jani , Räihä Jani , Kämäräinen Matti , Jylhä Kirsti
Published: March 2020

Coastal areas are under rapid changes. Management to face flooding hazards in changing climate is of great significance due to the major impact of flooding events in densely populated coastal regions, where also important and vulnerable infrastructure is located. The sea level of the Baltic Sea is affected by internal fluctuations caused by wind, air pressure and seiche oscillations, and by variations of the water volume due to the water exchange between the Baltic Sea and the North Sea through the Danish Straits. The highest sea level extremes are caused by cyclones moving over the region. The most vulnerable locations are at the ends of the bays. St. Petersburg, located at the eastern end of the Gulf of Finland, has experienced major sea floods in 1777, 1824 and 1924.

In order to study the effects of the depths and tracks of cyclones on the extreme sea levels, we have developed a method to generate cyclones for numerical sea level studies. A cyclone is modelled as a two-dimensional Gaussian function with adjustable horizontal size and depth. The cyclone moves through the Baltic Sea region with given direction and velocity. The output of this method is the gridded data set of mean sea level pressure and wind components which are used as an input for the sea level model. The internal variations of the Baltic Sea are calculated with a numerical barotropic sea level model, and the water volume variations are evaluated using a statistical sea level model based on wind speeds near the Danish Straits. The sea level model simulations allow us to study extremely rare but physically plausible sea level events that have not occurred during the observation period at the Baltic Sea coast. The simulation results are used to investigate extreme sea levels that could occur at selected sites at the Finnish coastline.
New Vegetation Radiative Transfer Schemes for Land Surface Models
Authors: Quaife Tristan
Published: March 2020

The land surface components of climate and Earth system models tend to utilise relatively simple representations of vegetation radiative transfer processes to determine key land surface properties such as albedo, land surface temperature and the absorption of sunlight for photosynthesis. This simplicity is driven, in large part, by a need for computational efficiency. However, a growing number of studies have pointed to the need for more complex radiative transfer in these models.

An almost ubiquitous assumption in such radiative transfer schemes is that a vegetation canopy can be represented by a plane-parallel, turbid medium – a perfectly flat box in which scattering elements (i.e. leaves, branches, trunks, etc.) are randomly distributed. Real canopies typically exhibit quite complex, non-random structures often involving the clumping of leaves and branches at multiple scales. Furthermore, the optical properties of canopies are typically assumed to be vertically and horizontally homogeneous which does not allow for realistic representation of, for example, forest stands with mixed species or understory vegetation.

This presentation examines recent developments that have the potential to overcome these and other deficiencies in land surface model radiative transfer schemes, whilst maintaining sufficient computational efficiency to make them viable for inclusion in climate and Earth system models. This is achieved by using the same solutions to the transfer problem as currently employed in climate models as the building blocks to construct canopies that can vary both vertically and horizontally. 

 
Towards the Development of a High-resolution, Global Streamflow and Flood Forecasting System – An U.S. Interagency Collaboration Effort
Authors: Gangrade Sudershan , Morales-Hernandez Mario , Tavakoly Ahmad A. , Arsenault Kristi R. , Wegiel Jerry , McCormack Kimberly , Wahl Mark , Kumar Sujay V. , Peters-Lidard Christa D. , Kao Shih-Chieh , Evans Katherine J.
Published: March 2020

This work provides an envisioned overview of scientific collaboration among multiple United States agencies including the National Aeronautics and Space Administration (NASA), U.S. Army Engineer Research and Development Center (ERDC), Oak Ridge National Laboratory (ORNL), and National Geospatial-Intelligence Agency (NGA) for the integration of existing data and model capabilities to support global scale water security applications. The primary objective is to develop a high-resolution, operational streamflow and flood forecasting system at the global scale, leveraging multiple process-based models, remote sensing data assimilation, and high-performance computing techniques. We present a preliminary case study that demonstrates the integration of the modeling framework using NASA’s Land Information System (LIS), ERDC’s Streamflow Prediction Tool (SPT), and ORNL’s GPU-accelerated 2D flood model (TRITON). Using the high-resolution terrain data from NGA, a historic flood event that occurred in March 2019 at Offutt Air Force Base in Nebraska, USA, was simulated on ORNL’s supercomputer, Summit. This benchmark test case is used to validate the modeling framework and to help establish a roadmap for the expanded modeling efforts at the global scale. In a broader sense, the proposed infrastructure will enable decision-makers to address issues such as transboundary water conflicts, flood and drought monitoring, and sustainable water resources management and to study their impacts on human, water-energy and natural systems in the short, medium and long term.
Building Cloud-Based Data Services to Enable Earth Science Workflows
Authors: Hanley John , Siemen Stephan , Hawkes James , Vuckovic Milana , Quintino Tiago , Pappenberger Florian
Published: March 2020

Weather forecasts produced by ECMWF and environmental services by the Copernicus programme act as a vital input for many downstream simulations and applications. A variety of products, such as ECMWF reanalyses and archived forecasts, are additionally available to users via the MARS archive and the Copernicus data portal. Transferring, storing and locally modifying large volumes of such data prior to integration currently presents a significant challenge to users. The key aim for ECMWF within the H2020 HiDALGO project (https://hidalgo-project.eu/) is to migrate these tasks to the cloud, thereby facilitating fast and seamless application integration by enabling precise and efficient data delivery to the end-user. The required cloud infrastructure development will also feed into ECMWF's contribution to the European Weather Cloud pilot which is a collaborative cloud development project between ECMWF and EUMETSAT.

The HiDALGO project aims to implement a set of services and functionality to enable the simulation of complex global challenges which require massive high performance computing resources alongside state-of-the-art data analytics and visualization. The HiDALGO use-case workflows are comprised of four main components: pre-processing, numerical simulation, post-processing and visualization. The core simulations are ideally suited to running in a dedicated HPC environment, while the pre-/post-processing and visualisation tasks are generally well suited to running in a cloud environment. Enabling and efficiently managing and orchestrating the integration of both HPC and cloud environments to improve overall performance and functionality is the key goal of HiDALGO.

ECMWF's role in the project will be to enable seamless integration of two pilot applications with its meteorological data and services (such as data exploration, analysis and visualisation) delivered via ECMWF's cloud and orchestrated by bespoke HiDALGO workflows. The demonstrated workflows show the increased value which can be created from weather forecasts, but also derived forecasts for air quality which are provided by the Copernicus Atmospheric Monitoring Service (CAMS).

This poster will give a general overview of HiDALGO project and its main aims and objectives. It will present the two test pilot applications which will be used for integration, and an overview of the general workflows and services within HiDALGO. In particular, it will focus on how ECMWF's cloud data and services will couple with the test pilot applications thereby improving overall workflow performance and enabling access to new data and products for the pilot users.
Global climate simulations at 2.8 km on GPU with the ICON model
Authors: Lapillonne Xavier , Sawyer William , Marti Philippe , Clement Valentin , Dietlicher Remo , Kornblueh Luis , Rast Sebastian , Schnur Reiner , Esch Monika , Giorgetta Marco , Alexeev Dmitry , Pincus Robert
Published: March 2020

The ICON modelling framework is a unified numerical weather and climate model used for applications ranging from operational numerical weather prediction to low and high resolution climate projection. In view of further pushing the frontier of possible applications and to make use of the latest evolution in hardware technologies, parts of the model were recently adapted to run on heterogeneous GPU system. This initial GPU port focus on components required for high-resolution climate application, and allow considering multi-years simulations at 2.8 km on the Piz Daint heterogeneous supercomputer. These simulations are planned as part of the QUIBICC project “The Quasi-Biennial Oscillation (QBO) in a changing climate”, which propose to investigate effects of climate change on the dynamics of the QBO.

Because of the low compute intensity of atmospheric model the cost of data transfer between CPU and GPU at every step of the time integration would be prohibitive if only some components would be ported to the accelerator. We therefore present a full port strategy where all components required for the simulations are running on the GPU. For the dynamics, most of the physical parameterizations and infrastructure code the OpenACC compiler directives are used. For the soil parameterization, a Fortran based domain specific language (DSL) the CLAW-DSL has been considered. We discuss the challenges associated to port a large community code, about 1 million lines of code, as well as to run simulations on large-scale system at 2.8 km horizontal resolution in terms of run time and I/O constraints. We show performance comparison of the full model on CPU and GPU, achieving a speed up factor of approximately 5x, as well as scaling results on up to 2000 GPU nodes. Finally we discuss challenges and planned development regarding performance portability and high level DSL which will be used with the ICON model in the near future.
Dam reoperation for controlling water-related diseases: the potential of floating solar for compensating hydropower losses
Authors: Piraccini Giacomo , Amaranto Alessandro , Bertoni Federica , Castelletti Andrea
Published: March 2020

Dam reoperation for controlling water-related diseases: the potential of floating solar for compensating hydropower losses.

Giacomo Piraccini1, Alessandro Amaranto1, Federica Bertoni1, Andrea Castelletti1

1Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy

Malaria is one of the leading causes of death in Sub-Saharan Africa, affecting around 200 million people in the region each year. In the proximity of hydropower reservoirs, the presence of large areas with stagnant water creates greater reproduction opportunities for Anopheles mosquitoes, and the number of disease cases is usually higher.  In this context, a soft mitigation strategy which is gaining much attention in recent years is controlling the water level in the lake to expose the Anopheles eggs right after laying. However, this operation strategy usually leads to both losses and fluctuation in hydropower production.

In this study, we evaluate the capability of floating solar technology to effectively compensate the loss in energy production occurring when avoiding the spread of malaria becomes an important factor in reservoir management. To do so, we implement a modelling framework where the floating solar plant size and the dam operation are jointly optimized with the objective of minimizing energy deficit, costs and malaria spread. As a demonstration, we study the Zambezi River, where the Kariba dam (shared between Zambia and Zambezi) is mainly operated for hydropower production. Here, we explore the potential tradeoffs between power generation and malaria spread by solving a joint planning (solar plant capacity)-management (dam operations) optimization problem using Evolutionary Multi-Objective Direct Policy Search (EMODPS). Numerical results show how a doubling in power generation can be obtained by covering about 1% of Kariba lake with floating solar panels. This highlights the potential of floating solar penetration in tropical climates, and the key role that the technology can play in both controlling water-related diseases and compensating hydropower production, especially in dry seasons.
Joint Acoustic and Electrical Measurements for Unfrozen Water Saturation of Frozen Saline Soil
Authors: Lyu Chuangxin , Ingeman-Nielsen Thomas , Ali Ghoreishian Amiri Seyed , Reidar Eiksund Gudmund , Grimstad Gustav
Published: March 2020

Abstract. The climate change has aroused great concern on the stability and durability of the infrastructure installed on permafrost, especially for frozen saline clay with a large amount of unfrozen water content at subzero temperature. The joint electrical resistivity and acoustic velocity measurements are conducted for frozen saline sand and onsøy clay with 50% clay content and 20~40 g/L salinity in order to determine the unfrozen water content. A systematic program of tests involves the saline sand with different salinity, natural onsøy clay with the variable of temperature and freezing-thawing cycles and reconstituted onsøy clay with distinctive density and salinity. The data analysis of measurement results in combination with previous joint measurements for frozen soil resolves the effect of temperature, salinity, soil type and freezing-thawing cycles on the acoustic and electrical properties. An increase of temperature, fine content and salinity results in a decrease of both acoustic velocity and electrical resistivity. Electrical resistivity is sensitive to salinity, while acoustic velocity changes substantially near thawing temperature. We also find that both natural and reconstituted clay with similar water content and salinity show quite different acoustic velocity and electrical resistivity, which indicates that ice crystal structures are distinctive between natural and reconstituted samples. Besides, P-wave velocity is much more sensitive to the fabric change or induced cracks than electrical resistance during freezing-thawing cycles.  In the end, acoustic models like the weighted equation (Lee et al., 1996), Zimmerman and King’s model (King et al., 1988) and BGTL (Lee, 2002) are applied to the UWS estimates based on P-wave velocity and electrical models like Archine’s law are adopted based on electrical resistance. Both estimated UWS from different methods is not always consistent. The difference can be up to 20%.

Keywords: Frozen Saline Clay, Acoustic Velocity, Electrical Resistance, Unfrozen Water Saturation

References:

King, M. S., Zimmerman, R. W., & Corwin, R. F. (1988, May). Seismic and Electrical-Properties of Unconsolidated Permafrost. Geophysical Prospecting, 36(4), 349-364. https://doi.org/10.1111/j.1365-2478.1988.tb02168.x

Lee, J. S. (2002). Biot–Gassmann theory for velocities of gas hydrate-bearing sediments.

Lee, M. W., Hutchinson, D. R., Collett, T. S., & Dillon, W. P. (1996). Seismic velocities for hydrate-bearing sediments using weighted equation. Journal of Geophysical Research: Solid Earth, 101(B9), 20347-20358. https://doi.org/10.1029/96jb01886

 
Methods for measuring and modelling plastic transport and accumulation in large rivers
Authors: Liedermann Marcel , Pessenlehner Sebastian , Tritthart Michael , Gmeiner Philipp , Habersack Helmut
Published: March 2020

Although freshwater systems are known to be the transport paths of plastic debris to the ocean, studies in rivers are rare. In recent years, measurements are advancing, but they hardly address the spatial distribution of plastic debris in the whole water column. Waste collecting activities in the Nationalpark Donau-Auen – a part of the Austrian Danube River to the East of Vienna – indicate that increasing quantities of plastic waste can also be found near the banks and within the inundation areas of our rivers. The EU financed project "PlasticFreeDanube" tries to find the sources, environmental impacts, transported amounts and paths, compositions and possible plastic accumulation zones.

A robust, net-based device was developed which can be applied at high flow velocities and discharges even at large rivers. The device consists of a strong and stable equipment carrier allowing a steady positioning. Three frames can be equipped with 1-2 nets each, having different mesh sizes exposed over the whole water column. The methodology was tested in the Austrian Danube River, showing a high heterogeneity of microplastic concentrations over the cross-section but also vertically over the depth. It was found that even higher amounts of plastic can be transported in a subsurface layer or even bottom-near.

Three-dimensional numerical modelling has proven to be a great support in describing and analyzing plastic particle transport in flowing waters. Flow fields near river engineering structures such as groynes and guiding walls were characterized by the models as they are known to be plastic accumulation zones. The models can be used for predicting potential accumulation zones in Danubian inundation areas and can provide recommendations for creating “artificial” accumulation zones where plastic can be more easily extracted from the river.
Holocene hydroclimate of the Volga Basin recorded in speleothems from the Central and Southern Ural Mountains, Russia
Authors: Baker Jonathan , Dublyansky Yuri , Kadebskaya Olga , Scholz Denis , Koltai Gabriella , Li Hanying , Zhao Jingyao , Spötl Christoph , Cheng Hai
Published: March 2020

Hydroclimatic variability over the Volga River watershed (western Russia) strongly influences agricultural production, forest and grassland ecology, Caspian Sea level, and associated economic stability. Climate model forecasts of these variables suggest long-term increases in crop shortfalls and over-basin evaporation in the Volga and Caspian regions, respectively, but these projections currently lack validation from high-quality paleoclimate data. We present decadal-scale geochemical proxy data (δ13C, Mg/Ca, Sr/Ca) from 230Th-dated stalagmites retrieved from four caves along a 640-km north-south gradient in the Ural Mountains, which collectively cover the entire Holocene (11.7 ka to present). Orbital trends in δ13C and Mg/Ca are broadly coherent between Ural speleothems and suggest that following Early Holocene aridity, warm-season precipitation was paced by summer insolation and has gradually declined since ~8 ka, consistent with model hindcasting. Centennial-scale variability, which is exceptionally well replicated between the Southern (Kinderlinskaya Cave) and Central (Geologov-3 Cave) Ural sites, supports a dynamic link between Volga hydroclimate and sea-surface temperature in the northeastern North Atlantic and Barents Sea. Important discrepancies exist, however, with data from the southernmost cave sites, which may be related to past migration of a strong latitudinal precipitation gradient that characterizes the modern basin and approximates the limit of North Atlantic influence. Finally, we conduct model-data comparisons and review our composite dataset in light of pollen- and soil-based proxies from across the Volga region, as well as reconstructions of Caspian Sea level. Our results provide a temporally well-constrained and spatially coherent portrait of Holocene hydroclimate for the Volga River watershed, thus constituting an important metric for future modeling studies.
Biomass burning pollution products C2H6, C2H2, HCOOH, and PAN in the Southern hemisphere UTLS region observed by the GLORIA instrument during the SouthTRAC HALO aircraft campaign Sep-Nov 2019
Authors: Friedl-Vallon Felix , Ungermann Jörn , Johansson Sören , Wetzel Gerald , Geldenhuys Markus , Engel Andreas , Grooß Jens-Uwe , Gulde Thomas , Höpfner Michael , Hoor Peter , Kleinert Anne , Kretschmer Erik , Maucher Guido , Orphal Johannes , Piesch Christof , Preusse Peter , Rapp Markus , Riese Martin , Santee Michelle L. , Sinnhuber Björn-Martin
Published: March 2020

The Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) is an imaging Fourier transform spectrometer (iFTS) using a 2-dimensional detector array to record emission spectra in the mid-infrared region with high spatial resolution. GLORIA has been operated on the High Altitude and Long Range Research Aircraft (HALO) during the SouthTRAC campaign in September-November 2019. The campaign with base in Rio Grande (Tierra del Fuego) consisted of two observational periods, mainly in September and November 2019. Apart from many local flights, between the two phases HALO returned to Germany which allowed us to acquire long-range hemispheric cross-sections.

Two dimensional distributions of pollution species like C2H6, C2H2, HCOOH, and PAN, which are produced as primary and secondary products from biomass burning sources have been derived from the GLORIA observations. We will show that during the hemispheric cross sections as well as during some of the local flights, GLORIA observed pollution plumes with extensions of many kilometres in altitude and hundreds of kilometres horizontally with strongly enhanced concentrations of these species.

Trajectory analysis as well as comparisons to Microwave Limb Sounder (MLS) satellite observations show that the origin of plumes are mainly fires in South America and Africa, but also first signs of the Australian bush fires have been detected in the UTLS as early as November 2019.
Effects of tractor traffic on soil compaction, water infiltration and soil erosion in tilled and grassed vineyards
Authors: Biddoccu Marcella , Capello Giorgio , Cavallo Eugenio
Published: March 2020

Soil erosion is affected by rainfall temporal pattern and intensity variability. In vineyards, machines traffic is implemented with particular intensity from late spring to harvest, and it is responsible of soil compaction, that likely affects soil hydraulic properties, runoff, and soil erosion. Additionally, hydraulic and physical properties of soil are highly influenced by vineyards’ inter-rows soil management. The effect of machines traffic on soil compaction, hydrological and erosional processes has been investigated on a sloping vineyards with different inter-row soil managements (tillage and permanent grass cover) in the Alto Monferrato area (Piedmont, NW Italy). During the investigation (November 2016 – October 2018) soil water content, rainfall, runoff, and soil erosion were continuously monitored. Field-saturated hydraulic conductivity (Kfs), soil penetration resistance (PR) and bulk density (BD) were recorded periodically in portions of inter-rows affected and not by the machine traffic. In order to take into account temporal and management variability of soil compaction and hydrological properties, field-monitored data were statistically analysed, in order to identify existing relationships between climate and management variables and soil physical and hydrological variables. Very different yearly precipitation characterized the observed period, leading to higher bulk density and lower infiltration rates were in the wetter year, especially in the tilled vineyard, whereas soil penetration resistance was generally higher in the grassed plot, and in drier conditions. Soil bulk density and penetration resistance in tracked soil of the tilled plot increase, compared to the grassed plot, after only one to three tractor passages following tillage operation, especially in the topsoil (first 10 cm). Soil compaction affects water infiltration, especially in the wet year. In the tilled vineyard, one tractor passage on wet soil after tillage operation dramatically reduced Kfs from over 1000 to near 1 mm h-1, while with grass cover Kfs remained above the usual rain-intensity values, allowing water to infiltrate the soil. By means of linear and multilinear regression, significant relationships have been found to relate hydraulic conductivity and soil penetration resistance with soil water content, weather variables and a factor that takes into account the number of tractor passages and the elapsed time from last soil disturbance. Lastly, runoff and soil erosion were higher in the tilled plot, even if lower than the long-period average values. Indeed, in the wet year, management with grass cover reduced considerably runoff (-76%) and soil loss (-83%) compared to tillage and, in the dry season.
Integrating preferences and social values for ecosystem services in local ecological management: A framework applied in Xiaojiang Basin, Southwest of China
Authors: Wu Xiuqin , Zhang Weixin , Yu Yang , Pereira Paulo
Published: March 2020

Ecosystem services (ES) are defined as material and non-material benefits that people derive directly or indirectly from nature, normally divided in provisioning, regulating and cultural. Previous works have made great progress in mapping and assessing ecosystem services (ES) that are directed toward exploring various aspects of ecological changes and economic values. These preferences, however, may neglect the important role of people who are the direct beneficiaries in this ecosystem. Therefore, including these stakeholders in ecosystem services assessment identifies their relations and perceptions between ecosystem services and society. In order to quantify and map these relations and perceptions, we designed and implemented an analytical framework based on the Public Participatory Geographic Information System (PPGIS) method to explore local stakeholders’ (Farmers, Government managers/Experts, and Company employees) similarities and differences in recognition of preferences and social values for ecosystem services in a typical Karst basin. Our results showed that remarkable differences appeared in preferences for ecosystem services across three groups. Farmers gave more preferences to provisioning services, Government managers/Experts to regulating and cultural services, and Company employees’ preferences were individualized. The spatial distributions and relations of social values for ecosystem services also showed great differentials. Provisioning services were always related to specific natural conditions, regulating services to forests, and cultural services to specific locations around tourism localities, forest, and wetland parks. The three stakeholder groups perceived more synergies than tradeoffs between the different ecosystem services. Landscape beauty was the most influential service in Farmers’ and Company employees’ perceptions, while Local climate change regulation was the most influential service in those of Government managers/Experts. The local stakeholders’ surveys can improve the enthusiasm of the local people to participate in environmental management and provide more socio-ecological information to help the managers alleviate the conflicts among different stakeholders.
Monte Carlo simulation of polarized radiative transfer over the ocean surface
Authors: Russkova Tatiana , Shmirko Konstantin
Published: March 2020

An increasing number of remote sensing instruments measure the polarization state of electromagnetic radiation. The polarization state contains all the information about the sensing object that is available to optical measurement methods. Taking into account the polarization during the radiative transfer simulation leads to a redistribution of energy between the components of the Stokes vector, thereby introducing a correction to the scalar approximation, the value of which may be significant. This information potentially can be used to improve algorithms for removal of surface glint, underwater visibility, to improve radiative transfer retrieval methods if the polarization-sensitive sensors are employed.

A Monte Carlo polarized radiative transfer model termed MCPOLART for the ocean-atmosphere system that is able to predict the total and the polarized signals has been developed.  Since the ocean surface is not smooth, the radiation model must take into account waves that occur under the influence of wind. The Cox-Munk ocean wave slope distribution model is used in calculation of the reflection matrix of a wind-ruffled ocean surface. Sensitivity studies are conducted for various ocean-surface and atmospheric conditions, geometric schemes of lighting and observation.  

This work was supported by the Russian Science Foundation (project No. 19-77-10022).
A method to differentiate hydrocarbon source (oil vs methane) in authigenic carbonate rock from seeps
Authors: Sun Yuedong , Gong Shanggui , Li Niu , Peckmann Jörn , Jin Meng , H. Roberts Harry , Chen Duofu , Feng Dong
Published: March 2020

Abstract

Numerous marine hydrocarbon seeps have been discovered in the past three decades, the majority of which are dominated by methane-rich fluids. However, an increasing number of modern oil seeps and a few ancient oil-seep deposits have been recognized in recent years. Oil seepage exerts significant control on the composition of the seep-dwelling fauna and may have impacted the marine carbon cycle through geological time to a greater extent than previously recognized. Yet, distinguishing oil-seep from methane-seep deposits is difficult in cases where δ13Ccarb values are higher than approximately -30‰ due to mixing of different carbon sources. Here, we present a comparative study of authigenic carbonates from oil-dominated (site GC232) and methane-dominated (site GC852) seep environments of the northern Gulf of Mexico, aiming to determine the geochemical characteristics of the two types of seep carbonates. We analyzed (1) Major and trace element compositions of carbonates, (2) total organic carbon (TOC), total nitrogen (TN) and carbon isotope (δ13CTOC) of residue after decalcification, (3) sulfur isotope signatures of chromium reducible sulfur (CRS, δ34SCRS) and residue after CRS extraction (δ34STOS ), as well as (4) sulfur contents (TOS) of residue after CRS extraction. Carbonates from the studied oil seep are dominated by aragonite and exhibit lower δ34SCRS values, suggesting carbonate precipitation close to the sediment surface. In addition, oil-seep carbonates are characterized by higher TOC and TOS contents and higher TOC/TN ratios, as well as less negative δ13CTOC values compared to methane-seep carbonates, probably reflecting a contribution of residual crude oil enclosed in oil-seep carbonates. Very low δ13CTOC values (as low as −68.7‰, VPDB) and low TOC/TN ratios of methane-seep carbonates indicate that the enclosed organic matter is derived mainly from the biomass of methanotrophic biota. This study presents new geochemical data that will allow the discrimination of oil-seep from methane-seep deposits. Although some of the geochemical patterns are likely to be affected by late diagenesis, if applied with caution, such patterns can be used to discern the two end-member types of seepage – oil seeps and methane seeps – in the geological record.
Using AutoRegressive Integrated Moving Average and Gaussian Processes with LSTM neural networks to predict discrete geomagnetic signals
Authors: Asimopolos Laurentiu , Stanciu Alexandru , Asimopolos Natalia-Silvia , Balea Bogdan , Dinu Andreea , Asimopolos Adrian-Aristide
Published: March 2020

In this paper, we present the results obtained for the geomagnetic data acquired at the Surlari Observatory, located about 30 Km North of Bucharest - Romania. The observatory database contains records from the last seven solar cycles, with different sampling rates.

We used AR, MA, ARMA and ARIMA (AutoRegressive Integrated Moving Average) type models for time series forecasting and phenomenological extrapolation. ARIMA model is a generalization of an autoregressive moving average (ARMA) model, fitted to time series data to predict future points in the series

We made spectral analysis using Fourier Transform, that gives us a relevant picture of the frequency spectrum of the signal component, but without locating it in time, while the wavelet analysis provides us with information regarding the time of occurrence of these frequencies. 

Wavelet allows local analysis of magnetic field components through variable frequency windows. Windows with longer time intervals allow us to extract low-frequency information, medium-sized intervals of different sizes lead to medium-frequency information extraction, and very narrow windows highlight the high-frequencies or details of the analysed signals.

We extend the study of geomagnetic data analysis and predictive modelling by implementing a Long Short-Term Memory (LSTM) recurrent neural network that is capable of modelling long-term dependencies and is suitable for time series forecasting. This method includes a Gaussian process (GP) model in order to obtain probabilistic forecasts based on the LSTM outputs. 

The evaluation of the proposed hybrid model is conducted using the Receiver Operating Characteristic (ROC) Curve that provides a probabilistic forecast of geomagnetic storm events. 

In addition, reliability diagrams are provided in order to support the analysis of the probabilistic forecasting models.

The implementation of the solution for predicting certain geomagnetic parameters is implemented in the MATLAB language, using the Toolbox Deep Learning Toolbox, which provides a framework for the design and implementation of deep learning models.

Also, in addition to using the MATLAB environment, the solution can be accessed, modified, or improved in the Jupyter Notebook computing environment.
Indo-Pacific warm pool expansion modulates MJO lifecycle
Authors: Dasgupta Panini , Koll Roxy Mathew , McPhaden Michael J. , Suematsu Tamaki , Zhang Chidong , Kim Daehyun
Published: March 2020

The Madden–Julian Oscillation (MJO) is the most dominant mode of intraseasonal
variability in the tropics, characterized by an eastward propagating zonal circulation pattern
and rain bands. MJO is very crucial phenomenon due to its interactions with other
timescales of ocean-atmosphere like El Niño Southern Oscillation, tropical cyclones,
monsoons, and the extreme rainfall events all across the globe. MJO events travel almost
half of the globe along the tropical oceans, majorly over the Indo-Pacific Warm Pool
(IPWP) region. This IPWP region has been warming during the twentieth and early twenty-
first centuries in response to increased anthropogenic emissions of greenhouse gases and
is projected to warm further. However, the impact of the warming of the IPWP region on
the MJO life cycle is largely unknown. Here we show that rapid warming over the IPWP
region during 1981–2018 has significantly changed the MJO life cycle, with its residence
time decreasing over the Indian Ocean by 3–4 days, and increasing over the Indo-Pacific
Maritime Continent by 5–6 days. We find that these changes in the MJO life cycle are
associated with a twofold expansion of the Indo-Pacific warm pool. The warm pool has
been expanding on average by 2.3 × 105 km2 per year during 1900–2018 and at an
accelerated average rate of 4 × 105 km2 per year during 1981–2018. The accelerated
warm pool expansion has increased moisture in the lower and middle troposphere over
IPWP and thereby increased the gradient of lower-middle tropospheric moisture between
the Indian Ocean and western Pacific. This zonal gradient of moisture between the Indian Ocean
and west Pacific and the increased subsidence over the Indian ocean due to increased
convective duration of MJO over maritime continent are likely the reasons behind the
changing lifecycle of MJO.
Cold avalanche, “super subduction”, mantle overturn, followed by buoyant subduction of an oceanic plateau and the formation of TTG´s during the Eocene in Viti Levu, Fiji islands
Authors: Sommer Holger , Kröner Alfred , Jacob Dorrit E. , Che Xiao-chao , Wong Jean , Xie Hangqiang
Published: March 2020

Tonalite, Trondhjemite, Granodiorite (TTG) rocks in Viti Levu, Fiji islands formed through hydrous melting of gabbroic oceanic crust at low-pressure amphibolite-facies conditions caused by flat subduction of an oceanic plateau from Yavuna creek. During mid Miocene time, magmatic underplating took place and a Qtz-diorite unit was formed out of the gabbro under granulite-facies conditions. The investigated TTG´s occur as stocks and veins within the older gabbroic unit of the Yavuna Pluton.

Zircon ages show the parental gabbro to be ~47.5 Ma in age, whereas the TTG´s, which can be subdivided into a tonalite and a Qtz-diorite suite, are ~37.1 Ma and ~16.5 Ma, old respectively. The average d18O value of ~4.8 in zircon selected from the parental gabbro and the tonalite suggest a very homogenous mantle source. However, about 50% of the analyzed zircons from the gabbroic and tonalitic rock samples showing lower d18O values, and these are interpreted as reflecting interaction of hydrothermally altered seafloor with the deep depleted mantle source. eHf in zircon values of ~13 in the analyzed TTG´s are interpreted as reflecting typical juvenile continental crust. PerpleX whole-rock calculations suggest that the tonalite formed by melting of the gabbro through decompression under water-saturated amphibolite-facies conditions at a temperature of ~770 °C and a pressure of ~3.8 kbar, whereas the Qtz-diorite formed at a temperature up to ~900 °C at very shallow depth close to the Earth’s surface caused by the emplacement of a magmatic underplate during the mid Miocene. Our investigation provides new evidence for episodic growth of continental crust < 0.1 Ga in the South Pacific region.
Large wood and stream longitudinal disconnectivity
Authors: Wohl Ellen , Scamardo Julianne , Iskin Emily
Published: March 2020

Large wood historically influenced diverse geomorphic and ecological processes in channels from first-order streams to major rivers. Centuries of deforestation and wood removal from channels have significantly reduced the presence of wood. The presence of large wood tends to decrease longitudinal connectivity, but increases lateral and vertical connectivity that arises from the presence of wood as an obstacle in the channel. Channel-spanning logjams, in particular, enhance vertical connectivity via hyporheic exchange flow and lateral connectivity via overbank flow, channel avulsion, lateral channel migration, or formation of secondary channels. In mountain streams, these effects are likely to be more pronounced in relatively wide, low gradient reaches with thicker alluvium and greater space for floodplain development and channel lateral mobility. River restoration increasingly includes maintaining or reintroducing large wood to channels, but there are relatively few studies that can be used to constrain management targets by providing data on instream large wood loads in unmanaged streams in diverse geographic settings. Here, we document the longitudinal distribution and persistence of logjams in the US Southern Rocky Mountains over a period of a decade. Key results include: (1) The longitudinal distribution of logjams varies significantly between successive stream reaches. Reaches are hundreds to thousands of meters in length and defined based on consistent stream gradient and channel lateral confinement. (2) Individual logjams change on an annual basis and typically persist less than a decade, although new logjams form frequently. (3) Individual logjams are more persistent in wide, low gradient reaches. (4) The population of logjams within a reach is more resilient to major floods in wide, low gradient reaches. The continuing breakup of jams and formation of new jams underscores the importance of ongoing wood recruitment in a natural river corridor. The results also imply that large wood reintroduction may be most effectively focused on specific types of wood process domains where the persistence and geomorphic effects of large wood are enhanced.
Using the radar- and ground-based measurements for rainfall floods modeling in small catchments (the Polomet' river, Russia)
Authors: Grek Elena , Zhuravlev Sergey
Published: March 2020

The previous research had shown that change of rainfall structure is taking place over Russia which increases the probability of occurrence of hazardous hydrological phenomena such as flash rainfall floods. Thus, the relevance and significance of the study is determined by the necessity of taking into account the structural changes of precipitation for reliable estimates of rainfall runoff characteristics in terms of climate change. The data of this study are comprehensive and consist of various sources of hydrometeorological information, including ground-based observations of precipitation and runoff, radar data. The assessment of the changes occurred in the maximum rainfall runoff and daily rainfall depth within the Russian part of the Baltic Sea basin was carried out in this study. The majority of the basins in our study showed positive trends in maximum discharge. The results of the work describe the experience of using different types of meteorological information of precipitation for rainfall floods modeling. The open-source SWAT (Soil and Water Assessment Tool) hydrological model was utilized. Small catchment (631 km2) situated in the Polomet’ River basin were chosen as the object of test modeling. The simulation efficiency is assessed using the coefficient of determination R2, Nash–Sutcliffe model efficiency coefficient (NSE), by comparing the mean values to standard deviations for the calculated and measured values of water discharge. This study was supported by RFBR, grant 19-35-90123 “Rain floods in the North-West Russia: assessment of variability and development of new forecasting methods”.
Advances in understanding localised variations in deformation experiments using numerical models
Authors: Cionoiu Sebastian , Tajčmanová Lucie , Khakimova Lyudmila
Published: March 2020

Phase transitions affect the physical properties of rocks (e.g. rheology) and control geodynamic processes at different spatial and time scales. However, the influence of deformation on phase transitions and their coupling is not well understood. 
Previous experiments, with both assembly-induced and additionally placed mechanical heterogeneities, have shown patterns in the phase transition distribution. Numerical modelling (2D, viscous finite difference models) have been used to correlate the experimental observations with the mechanic stress state. The locally increased mean stress in the models shows the best correlation with the formation of high-pressure polymorphs in experiments (Cionoiu et al. 2019).
Besides the distribution of polymorphs, grain-size and deformation patterns also vary across the samples due to stress, strain and pressure variations. To better understand the mechanisms contributing to these variations, we used advanced numerical models (3D, viscoelastic) to calculate the local distribution of first order parameters as pressure, stress and strain. The modelled stress and strain patterns are compared to the experimentally produced phase transformation distribution and previous (2D) modelling results. The 2D and 3D models differ partially regarding the quantification of local stresses – an effect that mainly depends on sample geometry (coaxial vs. general-shear). However, the qualitative fit between experiments, 2D and 3D models persists (i.e. the localisation of increased stresses or strain).
This contribution shows how numerical models, that closely represent the sample, can further improve the understanding of processes occurring in deformation experiments. Our new results emphasize that mechanically-induced stress-variations influence the grain-size and mineralogy of rocks which feeds back on their rheology.

References:
Cionoiu, S., Moulas, E. & Tajčmanová, L. Impact of interseismic deformation on phase transformations and rock properties in subduction zones. Sci Rep 9, 19561 (2019)
Rupture characteristics of the 2019 North Peru intraslab earthquake (Mw8.0)
Authors: Vallée Martin , Grandin Raphaël , Nocquet Jean-Mathieu , Villegas Juan-Carlos , Vaca Sandro , Xie Yuqing , Meng Lingseng , Ampuero Jean-Paul , Mothes Patricia , Jarrin Paul
Published: March 2020

According to GlobalCMT, the 2019/05/26 North Peru earthquake is the largest event since 1976 in the wide depth range between 70km and 550km. Its hypocentral location (at about 130km depth) inside the Nazca slab geometry, together with its normal focal mechanism, favor an origin related to slab bending. Owing to its magnitude and depth, this earthquake generated large coseismic displacements over a broad area, that were geodetically measured by InSAR and GNSS. By combining these observations with regional and teleseismic data, we invert for the rupture process of the event, and first focus on the actual focal plane. Inversion reveals that the steeper plane (dipping 55-60° to the East) is preferred. A clear northward propagation is also imaged, with rupture traveling ~200km in 60s, and with little extent in the dip direction. This narrow rupture aspect implies that the stress drop is significant, even if a simple duration-based measurement would not indicate so. These inversion results obtained at relatively low frequency (below 0.2Hz) are then thoroughly compared with back-propagation images obtained at higher frequency (at 0.5-4Hz), which also highlight the dominantly northward rupture propagation with an average rupture speed of about 3 km/s. Implication in terms of earthquake rupture dynamics and occurrence of such large intermediate depth earthquakes in slabs will finally be discussed.
    