bluuebunny/crossref_metadata_2025 huggingface dataset:
Drivers of reversible and irreversible slope deformations in a paraglacial environment
Authors: Oestreicher Nicolas , Roques Clément , Hugentobler Marc , Aaron Jordan , Loew Simon
Published: March 2021

Retreating glaciers around the world lead to rapid and profound changes in the surrounding landscapes. In the Alps, many glaciers are rapidly retreating and downwasting, substantially modifying stresses and hydro-thermal boundary conditions on the adjacent slopes. There is an increase in observations of bedrock responses and the formation of large-scale instabilities in paraglacial environments, but still a little knowledge about the underlying preparatory factors and drivers. This presentation is linked to the one from Hugentobler et al. in the same session. Both studies take place in the same catchment and address the same questions at different spatial scales, with other techniques and datasets.

We analyse surface deformation data monitored in a crystalline bedrock catchment, on the recently deglaciated slopes of the Great Aletsch Glacier (Valais, Switzerland). Our monitoring system has been in operation for six years and comprises 93 reflectors, 2 robotic TPS, and 4 cGPS stations distributed on both sides of the glacier tongue. This unique dataset allows studying the main processes involved at relevant spatial and temporal scales. The response of potential drivers for reversible and irreversible deformation is evaluated through combined multivariate (vbICA) and cross-correlation statistical analysis. We found that the variability in deformation near the glacier tongue is primarily controlled by glacier unloading through melting and seasonal groundwater fluctuations. At the catchment scale, the later effect is poroelastic and hence reversible, but we argue that it could also induce hydromechanical fatigue. By investigating the deformation's spatial pattern, we observed that the reversible deformation is mostly controlled by discrete structures such as hectometer-scale brittle-ductile shear zones striking subparallel to the valley axes and the main Alpine foliation. Field mapping and pressure monitoring during borehole drilling suggest that infiltration into the fractured rockmass is very heterogeneous and mainly controlled by the presence of interconnected tensile fractures.
The utilization of biochar as a conditioner for soil enrichment
Authors: Sovova Sarka , Storkova Natalie , Kurkova Marie , Enev Vojtech , Kalina Michal
Published: March 2021

The soil is becoming less fertile mainly due to today's way of land cultivation, erosion, lack of organic matter, aridity etc. Since soil represents the crucial environment for the life of a broad variety of living organisms, it is also a key material in agricultural production, one of the most important sources of food production, therefore, it is important to start working on its refining or at least on sustaining its crucial properties. There are few possible solutions to improve fertility, water retention, enhance plant growth etc. involving soil conditioners such as lignite, lignohumate or biochar. Biochar is a carbon-rich solid product of thermochemical conversion of biomass under anaerobic conditions (pyrolysis) abounding with attractive chemical (greenhouse gasses reduction, nutrient leaching reduction, plant growth enhancement) and physical (e.g. particles size distribution, porosity and surface area) properties. 

In present work, we focused on the study of the effect the application of EBC (European Biochar Certificate) certified biochar on growth of a model plant (Zea mays) in different –  common widespread soil types in the Czech republic (Regosol, Chernozem, Cambisol, Fluvisol…). Corn seeds were germinated in moist paper wipe for three days and planted into the flowerpot. The used dosage of biochar was 0, 10 and 20 g per 1 kg of dry weight of individual soils. Corn plants were cultivated under controlled conditions (temperature, moisture, cyclic irrigation, controlled light exposure etc.). Corn growth – height and number of leaves were measured three times a week for three months. The individual used soils samples and biochars were characterized before and after experiments by routine physico-chemical methods (pH, content of organic matter and humic substance, humic acids/fulvic acids ratio, total extractable macro and microelements…).
Identification of the socio-technical factors within geothermal exploration based on Plays with examples from Central America 
Authors: Chocobar Javiera , Johst Bernhardt , Bracke Rolf , Saenger Erik H.
Published: March 2021

     The development of geothermal exploration has benefited from the inclusion of exploration protocols based on geological Plays classically used in hydrocarbon exploration projects. Despite being a research topic in which many efforts have been devoted, it presents weaknesses when evaluating the role of the communities (the social dimension) during the exploration process. To address the lack of studies, a qualitative research has been carried out in Central America (Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua and Panamá) to determine the necessary factors to be considered in the social dimension within the geothermal exploration based in Plays.

     We have identified the social factors within each social dimension (demand, infrastructure, land access) and from this, a catalogue of the necessary activities required in the social dimension during the geothermal exploration process based on plays is proposed. The results of our survey will greatly contribute to the implementation of the Play-based exploration in geothermal projects because it reduces the risks associated in the initial phase of the exploration process and offers a step-by-step methodology that, when adapted to the needs of each country, can improve the efficiency of the current geothermal exploration protocols.
CO2 favours the accumulation of excess fluids in felsic magmas
Authors: Pistone Mattia , Caricchi Luca , Ulmer Peter
Published: March 2021

Volcano deformation and gas emissions provide insights into subsurface magmatic systems. Large discrepancies are observed between the volumes calculated from deformation data, mass of emitted gases, and volumes of erupted magmas. Such discrepancies hinder our capacity to predict the magnitude and intensity of imminent eruptions and are ascribed to the amount of excess fluids stored in magma reservoirs. High-pressure (1240 bar) and high-temperature (1200 °C) hot isostatic press experiments show that the amount of trapped excess fluids in haplogranitic magmas with variable crystal contents (30, 50, 60, and 70 vol.%) depends strongly on fluid composition. Magmas with CO2 excess fluids become permeable at much larger porosities (44% higher) with respect to the H2O-rich counterparts at equivalent crystallinity. Available excess gas geochemistry data calculated from volatile-saturated melt inclusion record, syn-eruptive SO2 emission, and erupted juvenile porosity data collected for crystal-rich andesite and crystal-poor dacite/rhyolite volcanoes with known eruption magnitude and intensity (Mt St Helens 1980, Pinatubo 1991, Soufrière Hills 1996, and Merapi 2010) reveal that the discrepancy between erupted magma volume and SO2 released during the eruption increases with CO2 excess in magmas. In agreement with our experiments, these data highlight that CO2-rich fluids enhance magma’s capacity to store excess volatiles and shed light on the largest discrepancies between pre-eruptive deformation, gas emissions, and eruption intensity and magnitude.
Turbulent Flow Structure around a Horizontal Circular Cylinder Placed on a Rough Bed
Authors: hanmaiahgari prashanth , devi kalpana
Published: March 2021

Pipelines that traverse a river are often buried beneath the river bed. However, the pipeline may be exposed due to scoured riverbed during floods. The exposed pipeline vibrates in a frequency band depending upon the flow velocity, size, and shape of the pipe. These vibrations are detrimental to the pipeline safety and stability due to their cyclic nature. In fact, these vibrations are induced by the turbulence around the cylinder which is a function of the flow velocity apart from the diameter of the cylinder and the bed roughness. The main objective of this paper is to investigate the structure of turbulent flow in the recirculation, reattachment and recovery regions behind a horizontal circular cylinder placed on the rough bed. In this direction, different experiments were conducted in a wide flume for various flow Reynolds numbers and cylinder Reynolds numbers. The Acoustic Doppler Velocimetry (ADV) was used for measuring the instantaneous point velocities. The raw velocity data were properly processed before the analysis. The approach flow was found to be a canonical near wall turbulent flow. In the immediate downstream of the cylinder, flow is characterized by recirculation, boundary layer reattachment and recovery. The reattachment length was determined using the established forward fraction method and reattachment length is independent of the flow Reynolds number. In addition, enhanced turbulence intensities, Reynolds shear stress, and turbulent kinetic energy were observed in the separated shear layer and they rapidly decreased in the recovery region. The present investigation will boost the understanding of hydraulics of flow around the horizontal bed-mounted cylindrical objects in rough bed natural streams under different flow conditions.

Keywords: Wall mounted horizontal cylinder; Boundary layer; Separated and reattached turbulent flows; Wall Wake flows; ADV; Open channel flow.
Gamified geo-challenges for immersive learning
Authors: Raimondo Tom , Payne Justin , Pollett Alicia , Hill Steve , Edmonds Roger
Published: March 2021

Project LIVE (Learning through Immersive Virtual Environments) is a cross-disciplinary initiative at the University of South Australia to embed immersive virtual and mixed reality experiences across the breadth of our STEM teaching program. In Earth and Environmental Science, the Project LIVE team has recently created a series of gamified geo-challenges and virtual tours of instructive field sites for use in undergraduate teaching, to both supplement and enhance traditional field experiences. This presentation will demonstrate our flagship geo-challenge developed for the Hallett Cove Geological Heritage Site in Adelaide, South Australia. Entitled Beyond the Ice, it incorporates several complementary elements including an immersive VR experience, web-based geotour, iOS and Android mobile learning game and 360 street view walking trail, all of which are freely available at https://www.projectlive.org.au/beyond-the-ice. The interactive VR quest challenges students to identify fossils with a virtual hand lens, measure glacial striations with a compass, and draw the outlines of rock folds and sedimentary layers that shape the landscape with digital ink. Students are also accompanied by the encyclopaedic ‘VT’ – a virtual robot guide with a geological memory spanning 600 million years – and can take part in quizzes, collect 3D pet rocks, and even uncover hidden ‘Easter eggs’ on their journey of scientific discovery. The uptake and impact of our geo-challenges across both undergraduate student cohorts and STEM outreach audiences will be discussed, along with further geoscience and community engagement opportunities currently being explored.
Partition of daily evapotranspiration using stable water isotope method and a modified Shuttleworth-Wallace Model for urban forest area
Authors: Gao Jun Jie , Chen Han , Huang Jinhui Jeanne , McBean Edward , Li Han , Zhang Jiawei , Lan Zhiqing
Published: March 2021

Quantification of the contribution of transpiration (T) to evapotranspiration (ET) is important to understand the impact of climate change on the hydrological cycle and guide precision irrigation. So far, few studies have examined seasonal variability of T/ET and its drivers under urban area. In this study, we applied a modified Shuttleworth-Wallace (S-W) model to partition ET for a locust tree forest in jinnan district of Tianjin city. The new model considers the impact of carbon dioxide emissions on vegetation transpiration and significantly improves the performance of the original S-W model. The Eddy Covariance (EC) and stable water isotope method was used to monitor and partition ET in locust tree forest. Isotope composition of ET (δET), soil evaporation (δE) and vegetation transpiration (δT) were determined using the Keeling-plot method, Craig-Gordon model and Steady-state assumption model (SSA), respectively. The verification result suggest the modified S-W model could provide reliable prediction for ET and its components. The modified S-W model estimated T/ET ranges from 0 to 1, with a near continuous increase over time in the early growing season when leaf area index (LAI) is small and then convergence towards a stable value when LAI is larger. The results show seasonal change in T/ET can be described well as a function of LAI, implying that LAI is a first order factor affecting ET partitioning, and soil moisture also influence the ET partitioning. This study reveals the change in T/ET patterns and its controlling factors in urban woodland areas. Understanding the impact of urbanization and human activities on the urban water cycle will allow more effective water use in urban environments.

 
Assessment of Meteorological and Hydrological Droughts and Floods over mainland Australia based on Drought Indices
Authors: Wang Wei , Shen Yunzhong , Wang Fengwei , Li Weiwei
Published: March 2021

Climate change has led to increased droughts and floods over mainland Australia, resulting in water scarcity, excessive surplus and socioeconomic losses. Therefore, it is of great significance to comprehensively evaluate droughts and floods from the meteorological and hydrological perspective. Firstly, we determine the Standard Precipitation and Evapotranspiration Index (SPEI) by correlation analysis to represent the meteorological conditions. To characterize the hydrological conditions, we calculate the hydrological drought indices including Standard Runoff Index (SRI), Soil Moisture Deficit Index (SMDI), and Total Storage Deficit Index (TSDI), using the runoff and soil moisture data from the Global Land Data Assimilation System (GLDAS) and the Terrestrial Water Storage Change (TWSC) data from Gravity Recovery And Climate Experiment (GRACE) respectively. Results show that the most severe hydrological drought over mainland Australia during the study period occurred from May 2006 to Jan. 2009 with the drought severity of -58.28 (cm months) and the most severe flood from Jun. 2010 to Jan. 2013 is with the severity of 151.36 (cm months). The comprehensive analysis of both meteorological and hydrological drought indices shows that both meteorological and hydrological drought indices can effectively detect the droughts and floods over mainland Australia. Moreover, the meteorological drought and flood are of higher frequency, while hydrological drought and flood have a relatively longer duration. Based on the cross-correlation analysis, we find that the SPEI can firstly reflect the droughts or floods over mainland Australia, and then the SRI, SMDI and TSDI reflect with the time lags of one, three and six months respectively. Furthermore, we calculate the frequency of drought and flood at the basin scale and find that SPEI and SMDI are equally sensitive to drought and flood, while TSDI is more sensitive to flood than drought. This study reveals the relationship between meteorological and hydrological conditions in mainland Australia in the last two decades and highlights its intensifying extreme climate conditions under the circumstances of the increasing temperature and complex changing precipitation.
Exponential earthquake productivity law
Authors: Shebalin Peter , Baranov Sergey , Matochkina Sofija , Krushelnitskiy Kirill
Published: March 2021

Mechanisms of stress transfer and probabilistic models have been widely investigated to explain earthquake clustering features. However, these approaches are still far from being able to link individual events and to determine the number of earthquakes caused by a single event. An alternative approach based on proximity functions allows  to generate hierarchical clustering trees and to identify pairs of nearest-neighbours between consecutive levels of hierarchy. Then, the productivity of an earthquake is the number of events of the next level to which it is linked. To account for scale invariance in the triggering process we use a relative magnitude threshold ΔM. Recently it was shown that the relative productivity attached to each event is a random variable that follows an exponential distribution. The exponential rate of this distribution does not depend on the magnitude of triggering events and systematically decreases with depth. Here we test a hypothesis that this stochastic property of the earthquake productivity is a consequence of high spatial heterogeneity of the background event rates. The study was supported by Russian Science Foundation, project no. 20-17-00180.
Modelling nitrogen transport across compartments over northern Europe
Authors: Hagemann Stefan , Daewel Ute , Matthias Volker , Stacke Tobias
Published: March 2021

River discharge and the associated nutrient loads are important factors that influence the functioning of the marine ecosystem. Lateral inflows from land carrying fresh, nutrient-rich water determine coastal physical conditions and nutrient concentration and, hence, dominantly influence primary production in the system. Since this forms the basis of the trophic food web, riverine nutrient concentrations impact the variability of the whole coastal ecosystem. This process becomes even more relevant in systems like the Baltic Sea, which is almost decoupled from the open ocean and land-borne nutrients play a major role for ecosystem productivity on seasonal up to decadal time scales.

 

In order to represent the effects of climate or land use change on nutrient availability, a coupled system approach is required to simulate the transport of nutrients across Earth system compartments. This comprises their transport within the atmosphere, the deposition and human application at the surface, the lateral transport over the land surface into the ocean and their dynamics and transformation in the marine ecosystem. In our study, we combine these processes in a modelling chain within the GCOAST (Geesthacht Coupled cOAstal model SysTem) framework for the northern European region. This modelling chain comprises:

 

Simulation of emissions, atmospheric transport and deposition with the chemistry transport model CMAQ at 36 km grid resolution using atmospheric forcing from the coastDat3 data that have been generated with the regional climate model COSMO-CLM over Europe at 0.11° resolution using ERA-Interim re-analyses as boundary conditions

Simulation of inert processes at the land surface with the global hydrology model HydroPy (former MPI-HM), i.e. considering total nitrogen without any chemical reactions

Riverine transport with the Hydrological Discharge (HD) model at 0.0833° spatial resolution

Simulation of the North Sea and Baltic Sea ecosystems with 3D coupled physical-biogeochemical NPZD-model ECOSMO II at about 10 km resolution

 

We will present first results and their validation from this exercise.

 
Numerical Research of Fujiangsha Waterway Based on a Depth-integrated Hydro-sediment-morphodynamic Model
Authors: Sun Mengzhe , Hu Peng , Li Youwei
Published: March 2021

Fujiangsha waterway is located in the tidal reach of Yangtze River, which is one of the key sections for channel regulation. The channel condition of the waterway is governed by the evolution of the channel bar and point bar. Groins are consequently set on both sides of the channel bar and the left edge of Fujiangsha island. To explore the impact of the regulation works on the evolution of bars and channels, a numerical research is carried out based on a depth-integrated hydro-sediment-morphodynamic model, using the method of nesting large-scale model with local model. The non-negligible impact on the quality and momentum of water flow caused by enormous sediment transport and drastic change of topography, as well as the complex flow condition in both tide and runoff working together, has been taken into account. The simulation successfully reproduces the hydrological process and changes of topography in Fujiangsha waterway. Results show that: 1) there is a silting trend at the head of the channel bar, and the effect of the regulation works in bar protection and sand stabilization is remarkable; 2) The erosion on both sides of the channel bar improves the channel condition, and the hydrodynamic performance of shallow area at the entrance of the south branch has been enhanced; 3) The control on the evolution of point bar is still weak, which will have an adverse effect on channel condition of north branch.
Gas bubble induced scalings in geothermal systems
Authors: Zacherl Lilly , Baumann Thomas
Published: March 2021

Scalings in geothermal systems are affecting the efficiency and safety of geothermal systems. An operate-until-fail maintenance scheme might seem appropriate for subsurface installations where the replacement of pumps and production pipes is costly and regular maintenance comprises a complete overhaul of the installations. The situation is different for surface level installations and injection wells. Here, monitoring of the thickness of precipitates is the key to optimized maintenance schedules and long-term operation.

A questionnaire revealed that operators of geothermal facilities start with a standardized maintenance schedule which is adjusted based on local experience. Sensor networks, numerical modelling and predictive maintenance are not yet applied. In this project we are aiming to close this gap with the development of a non-invasive sensor system coupled to innovative data acquisition and evaluation and an expert system to quantitatively predict the development of precipitations in geothermal systems and open cooling towers.

Previous investigations of scalings in the lower part of production pipes of a geothermal facility suggest that the disruption of the carbonate equilibrium is triggered by the formation of gas bubbles in the pump and subsequent stripping of CO2. Although small in it's overall effect on pH-value and saturation index, significant amounts of precipitates are forming at high volumetric flow rates. To assess the kinetics of gas bubble induced precipitations laboratory experiments were run. The experiment addresses precipitations at surfaces and at the gas bubbles themselves.
UK landfill methane emissions: Use of mobile plume measurements and carbon isotopic characterisation to reassess oxidation rates for open and closed sites 
Authors: Bakkaloglu Semra , Lowry Dave , Fisher Rebecca , France James , Nisbet Euan
Published: March 2021

Biological methane oxidation in landfill cover material can be characterised using stable isotopes. Methane oxidation fraction is calculated from the carbon isotopic signature of emitted CH4, with enhanced microbial consumption of methane in the aerobic portion of the landfill cover indicated by a shift to less depleted isotopic values in the residual methane emitted to air. This study was performed at four southwest England landfill sites. Mobile mole fraction measurement at the four sites was coupled with Flexfoil bag sampling of air for high-precision isotope analysis. Gas well samples collected from the pipeline systems and downwind plume air samples were utilized to estimate methane oxidation rate for whole sites. This work was designed to assess the impact on carbon isotopic signature and oxidation rate as UK landfill practice and waste streams have changed in recent years.

The landfill status such as closed and active, seasonal variation, cap stripping and site closure impact on landfill isotopic signature and oxidation rate were evaluated. The isotopic signature of 13C-CH4 values of emissions varied between -60 and -54‰, with an averaged value of -57 +- 2‰ for methane from closed and active landfill sites. Methane emissions from older, closed landfill sites were typically more enriched in 13C than emissions from active sites. This study found that the isotopic signature of 13C-CH4 of fugitive methane did not show a seasonal trend, and there was no plume observed from a partial cap stripping process to assess changes in 13C-CH4  isotopic signatures of emitted methane. Also, the closure of an active landfill cell caused a significant decrease in mole fraction of measured CH4, which was less depleted 13C in the emitted plume due to a higher oxidation rate. Methane oxidation, estimated from the isotope fractionation, ranged from 3 to 27%, with mean values of 7% and 15% for active and closed landfills, respectively. These results indicate that the oxidation rate is highly site specific.

 
Regulation of fungal decomposition at single-cell level
Authors: Op De Beeck Michiel , Troein Carl , Siregar Syahril , Gentile Luigi , Abbondanza Giuseppe , Peterson Carsten , Persson Per , Tunlid Anders
Published: March 2021

Ectomycorrhizal fungi use both extracellular enzymes and hydroxyl radicals to decompose soil organic matter (SOM) in a way that is similar to that of their saprotrophic wood decomposing ancestors. Although it are ultimately the individual hyphae that decompose SOM, it has remained unclear if it is also the local environmental conditions experienced by individual hyphae that control the decomposition activity of these hyphae or if it is the overall physiological status of the mycelium these hyphae are connected to that drives decomposition activity of hyphae. We set up an experimental system in which the decomposition activity of individual hyphae could be imaged using infrared (IR) microspectroscopy. Colonies of the ectomycorrhizal fungus Paxillus involutus were grown on solid, sterile lignin films which were amended with ferrihydrite minerals or not. The decomposition activity of individual hyphae was subsequently related to the local environmental conditions experienced by subsets of hyphae (presence or absence of ferrihydrite in lignin substrates) of a mycelial colony and the overall physiological status of the mycelium (difference in hydroxyl radical producing capacity of the mycelium and organic versus inorganic nitrogen nutrition). Using this experimental set-up, we have shown that the local conditions experienced by individual hyphae plays a key role in determining the decomposition activity of these hyphae, but the overall decomposition activity of the mycelium these hyphae were connected to also played a clear role. We also showed that hyphae which more actively oxidized the lignin substrate, also secreted more extracellular matrix materials, suggesting a functional involvement of fungal extracellular matrices in this decomposition process. We conclude that phenotypic heterogeneity occurring between genetically identical hyphal tips may be an important strategy for filamentous fungi to cope with heterogeneous and constantly changing soil environments.
Using long-lived radium isotopes as water-mass tracers in the North Sea and investigating their use for tracking artificial ocean alkalinization
Authors: Mears Chantal , Thomas Helmuth , Wolschke Hendrik
Published: March 2021

The North Sea’s location has made it an object of oceanographic study for over 150 years. But within the more recent past, this shelf sea with its strong continental shelf pump system has captivated science’s attention for a different reason: artificial ocean alkalinization (AOA). Through the enhancement of metabolic pathways or the addition of dissolved alkaline minerals into the ocean to draw down atmospheric CO2, AOA seems to offer a compelling option to mitigate climate change. But without judicious thought, human interaction could come at great cost. Alkalinity plays an integral role within a system’s biogeochemistry, and disruptions may result in large scale changes to small scale environments. But, within the North Sea, an extremely effective tracer of total alkalinity has been found, 228Ra. This isotope along with 226Ra, comprise the two long-lived isotopes of the Radium Quartet with half-lives of 1600yrs and 5.8yrs, respectively. As naturally occurring, sediment-derived radioisotopes, 228Ra and 226Ra have the potential to map the water-mass composition, the distribution patterns, and the associated timescales from shelf-sediment interaction to the open ocean. Furthermore, providing a possible method to shed light on the North Sea’s water-mass distributions, changing alkalinity patterns, and the potential effects of AOA. Over the course of this study, we will identify the basin’s key water-mass patterns and end members through the use of 226Ra and 228Ra, complemented by hydrological and carbonate parameters collected from the North Sea during the summers of 2018 and 2019 aboard the German research vessel Heincke. By employing inverse modelling techniques, we will investigate how AOA can cause changes on both a local and potentially global scale.
A variety of surface waves in ocean-bottom DAS records
Authors: Spica Zack , Viens Loïc , Castillo Castellanos Jorge , Akuhara Takeshi , Nishida Kiwamu , Shinohara Masanao , Yamada Tomoaki
Published: March 2021

Distributed acoustic sensing (DAS) can transform existing telecommunication fiber-optic cables into arrays of thousands of sensors, enabling meter-scale recordings over tens of kilometers. Recently, DAS has demonstrated its utility for many seismological applications onshore. However, the use of offshore cables for seismic exploration and monitoring is still in its infancy.
In this work, we introduce some new results and observations obtained from a fiber-optic cable offshore the coast of Sanriku, Japan. In particular, we focus on surface wave retrieved from various signals and show that ocean-bottom DAS can be used to extract dispersion curves (DC) over a wide range of frequencies. We show that multi-mode DC can be easily extracted from ambient seismo-acoustic noise cross-correlation functions or F-K analysis. Moderate magnitude earthquakes also contain multiple surface-wave packets that are buried within their coda. Fully-coupled 3-D numerical simulations suggest that these low-amplitude signals originate from the continuous reverberations of the acoustic waves in the ocean layer. 
Progress and remaining problems in subduction paleoseismology along the Pacific coast of northeast Japan
Authors: Sawai Yuki
Published: March 2021

In the last two decades, tsunami geology in northeast Japan (Hokkaido and Tohoku) has focused on extending the record of tsunamis beyond the range of historical documents in the region. In Hokkaido facing to southern Kuril trench, recurrent sandy deposits interbedded with peat are regarded as evidence of historical and prehistoric tsunamis. Distribution of one of the sand layers just below a historic tephra (Ko-c2; 1694 CE), so-called 17th-century tsunami deposit, exceeds historical and recent tsunami inundations in eastern Hokkaido. Numerical simulations to reproduce the distributions first suggested a multi-segment fault model with unimodal slip (Mw > 8.4; Nanayama et al., 2003 in Nature), and later with variable slip (Mw > 8.8; Ioki and Tanioka, 2016 in EPSL). Tohoku region, facing to Japan trench, has longer historical record than Hokkaido and the oldest historical earthquake is the Jogan event in 869 CE. Numerical simulations constrained by spatial distributions of the tsunami deposits, coastal submergence, and observation of the 2011 Tohoku tsunami deposit suggest that the 869 event was a plate-boundary rupture at least 200 km long along the Japan Trench (Mw > 8.3–8.6). After the 2011 Tohoku event, a large tsunami in 1454 CE (Kyotoku event) became reexamined and considered to have been generated by a rupture area including the Miyagi-oki region (part of the Jogan rupture). If the 869. 1454, and 2011 events were similar, recurrence of earthquakes in Japan trench is more periodic than southern Kuril trench.   This presentation is based on descriptions and discussion in Sawai (2020) in Earth Science Reviews.  
When color theory meets seismology: Principled visualization design for seismic hazard maps 
Authors: Schneider Max , Cotton Fabrice
Published: March 2021

Probabilistic seismic hazard estimates are a key ingredient of earthquake risk mitigation strategies and are usually communicated through seismic hazard maps. Though evidence exists that visual design properties are key for effective communication using such maps, few authors describe their approach in visualizing seismic hazard. Current maps use colors, legends and data classification schemes which are suboptimal, from the visualization perspective. As such, they have the danger of miscommunicating seismic hazard. We present a set of principles regarding color choice, legend design, and classification of the continuous hazard estimate for categorical mapping. These principles are based on (1) communication goals for the seismic hazard phenomenon, (2) empirically-validated recommendations from the visualization literature and (3) other best practices in map design. We discuss the process of redesigning the German seismic hazard map using these principles. A set of prototype maps adhering to these principles are presented. We also describe ongoing efforts to test the redesigned maps, as well as how to use them to further communicate the uncertainty around probabilistic hazard estimates.
The interplay between hydrological flushing and biogeochemical cycling in a 3rd order stream
Authors: Bieroza Magdalena , Heathwaite Ann Louise
Published: March 2021

High-resolution water quality data obtained with in situ sensors and analysers coupled to flow discharge records can reveal critical information on hydrochemical and biogeochemical functioning of aquatic ecosystems. In this study we explore a rich high-resolution hydrochemical dataset to synthesise the impact of hydrological flushing and biogeochemical cycling on water quality in a 3rd order groundwater-fed stream draining an agricultural catchment dominated by grassland.Our results show that despite large storm to storm diversity in hydrochemical responses, storm event magnitude and timing have a critical role in controlling the type of mobilisation, flushing and cycling behaviour. These results can be used to evaluate pollution risks in streams and their effects on freshwater quality.
MHD simulations of magnetospheric response to a strong solar wind density pulse
Authors: Samsonov Andrey , Carter Jennifer A. , Branduardi-Raymont Graziella , Sembay Steven
Published: March 2021

On 16-17 June 2012, an interplanetary coronal mass ejection with an extremely high solar wind density (~100 cm-3) and mostly strong northward (or eastward) interplanetary magnetic field (IMF) interacted with the Earth’s magnetosphere. We have simulated this event using global MHD models. We study the magnetospheric response to two solar wind discontinuities. The first is characterized by a fast drop of the solar wind dynamic pressure resulting in rapid magnetospheric expansion. The second is a northward IMF turning which causes reconfiguration of the magnetospheric-ionospheric currents. We discuss variations of the magnetopause position and locations of the magnetopause reconnection in response to the solar wind variations. In the second part of our presentation, we present simulation results for the forthcoming SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) mission. SMILE is scheduled for launch in 2024. We produce two-dimensional images that derive from the MHD results of the expected X-ray emission as observed by the SMILE Soft X-ray Imager (SXI). We discuss how SMILE observations may help to study events like the one presented in this work.
Modification of the k-epsilon scheme and its application for describing turbulence in inland water bodies
Authors: Soustova Irina , Troitskaya Yuliya , Gladskikh Daria
Published: March 2021

A parameterization of the Prandtl number as a function of the gradient Richardson number is proposed in order to correctly take into account stratification when calculating the thermohydrodynamic regime of inland water bodies. This parameterization allows the existence of turbulence at any values ​​of the Richardson number.

The proposed function is used to calculate the turbulent thermal conductivity coefficient in a k-epsilon mixing scheme. Modification is implemented in the three-dimensional hydrostatic model developed at the Research Computing Center of Moscow State University.

It is demonstrated that the proposed modification (in contrast to the standard scheme with a constant Prandtl number) leads to smoothing all sharp changes in vertical distributions of turbulent mixing parameters (turbulent kinetic energy, temperature and thickness of the shock layer) and imposes a Richardson number-dependent relation on the empirical constants of k-epsilon turbulent mixing scheme.

The work was supported by grants of the RF President’s Grant for Young Scientists (MK-1867.2020.5) and by the RFBR (19-05-00249, 20-05-00776). 
Attributing the global increase in permafrost temperatures to human induced climate change
Authors: Gudmundsson Lukas , Kirchner Josefine , Gädeke Anne , Burke Eleanor , Biskaborn Boris K. , Noetzli Jeannette
Published: March 2021

Permafrost temperatures are increasing at the global scale, resulting in permafrost degradation. Besides substantial impacts on Arctic and Alpine hydrology and the stability of landscapes and infrastructure, permafrost degradation can trigger a large-scale release of carbon to the atmosphere with possible global climate feedbacks. Although increasing global air temperature is unanimously linked to human emissions into the atmosphere, the attribution of observed permafrost warming to anthropogenic climate change has so far mostly relied on anecdotal evidence. Here we apply a climate change detection and attribution approach to long permafrost temperature records from 15 boreholes located in the northern Hemisphere and simulated soil temperatures obtained from global climate models contributing to the sixth phase of the Coupled Model Intercomparison Project (CMIP6). We show that observed and simulated trends in permafrost temperature are only consistent if the effect of human emissions on the climate system is considered in the simulations. Moreover, the analysis also reveals that neither simulated pre-industrial climate variability nor the effects natural drivers of climate change (e.g. impacts of large volcanic eruptions) suffice to explain the observed trends. While these results are most significant for a global mean assessment, our analysis also reveals that simulated effects of anthropogenic climate change on permafrost temperature are also consistent with the observed record at the station scale. In summary, the quantitative combination of observed and simulated evidence supports the conclusion that anthropogenic climate change is the key driver of increasing permafrost temperatures with implications for carbon cycle-climate feedbacks at the planetary scale.
A nested configuration of WRF-NOAHMP for process studies and the development of turbulence parameterizations over the SGP site
Authors: Bauer Hans-Stefan , Späth Florian , Behrendt Andreas , Wulfmeyer Volker , Lange Diego
Published: March 2021

We apply the WRF-NOAHMP model system in a nested configuration from the mesoscale down to the turbulence-permitting resolution of 100 m over the Southern Great Plains. Driven by the ECMWF operational analysis, this setup allows simulations with realistic lower boundary and meteorological forcing. A consistent set of physical parameterizations is applied through the whole chain of domains.

Using this setup, the evolution of the planetary boundary layer and land-atmosphere (L-A) feedback were investigated for selected days during the Land Atmosphere Feedback Experiment (LAFE) performed in August 2017 at the ARM SGP site. The model performance in representing the boundary layer evolution at different horizontal resolutions is presented. Also, detailed comparisons of turbulence parameters derived from the parameterized and turbulence-permitting simulations with observations are presented. The latter provides insight into the performance of turbulence parameterizations and potential improvements.

First comparisons with observations revealed that only the turbulence-permitting simulations realistically represent the temporal evolution and the internal structure of the daytime convective boundary layer as well as the morning and evening transitions. Statistical comparisons with lidar observations revealed differences in details as in the representation of vertical gradients or the variability in the boundary layer.

The results demonstrate that this model configuration is a valuable tool complementing high-resolution observations for the investigation of turbulent processes as well as the test and development of turbulence parameterizations.
Revised brGDGT fractional abundances and warm-season temperatures strengthen relationships between brGDGTs and environmental variables
Authors: Raberg Jonathan H. , Blumm Aria , Harning David J. , Crump Sarah E. , de Wet Greg , Dildar Nadia , Kopf Sebastian , Geirsdóttir Áslaug , Miller Gifford H. , Sepúlveda Julio
Published: March 2021

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are an important tool for reconstructing terrestrial paleotemperatures from lake sediments. In addition to temperature, however, the distribution of these bacterial membrane lipids is influenced by other environmental variables such as pH, conductivity, and dissolved oxygen. Furthermore, though most brGDGT calibrations are performed against mean annual air temperature (MAT), there is considerable evidence that their distributions are more closely tied to warm-season conditions. Here, we present a new method for analyzing brGDGT data that deconvolves the influences of temperature, conductivity, and pH. Additionally, we measure brGDGT distributions in surface sediments from 43 high-latitude lakes with low MAT and high seasonality. In combination with a globally compiled lake sediment dataset, these samples show a clear warm-season bias in brGDGT-derived temperatures. They also show lake water conductivity to be the second-most important variable in controlling brGDGT distributions. We use the compiled dataset and new fractional abundances to generate brGDGT calibrations for warm-season air temperatures and lake water conductivity and pH for use in lake sediments globally.
The effects of CO2 increase and its link to the mass extincton at the Permo-Triassic boundary
Authors: Zoura Despina , Hill Daniel J. , Hunter Stephen J. , Haywood Alan M. , Wignall Paul B.
Published: March 2021

The Permo–Triassic Boundary (PTB) marks a time of profound climatic change. Near the PTB (~252 Ma), the largest known mass extinction occurred with more than 90% of marine species and 70% of terrestrial species became extinct. The mass extinction is linked to a massive warming event at the PTB, where tropical regions became too hot for survival ofspecies. The increase in atmospheric CO2 during the Permian and the PTB is mainly attributed to the decrease of chemically weatherable fresh silicate rock due to orogenesis, and the CO2 released in the atmosphere from the Siberian Traps. In this study, we use the UK Met Office fully coupled HadCM3L General Circulation Model (GCM) to perform Permo-Triassic climate simulations with different atmospheric CO2 values that encompass most of the estimates of atmospheric CO2 concentration during this time, to provide more insights about the climate changes during the end Permian – early Triassic. Specifically, we focus on: a) the spatial extension of dry conditions/lethally hot temperatures under different CO2 conditions, b) the seasonal surface temperature difference and precipitation changes at higher latitudes and c) the effects of increased atmospheric CO2 on the large-scale wind and monsoonal circulation. 
Data-driven modeling decadal-to-centennial ENSO variability and its response to external forcing
Authors: Seleznev Aleksei , Mukhin Dmitry , Gavrilov Andrey , Feigin Alexander
Published: March 2021

We investigate the decadal-to-centennial ENSO variability based on nonlinear data-driven stochastic modeling. We construct data-driven model of yearly Niño-3.4 indices reconstructed from paleoclimate proxies based on three different sea-surface temperature (SST) databases at the time interval from 1150 to 1995 [1]. The data-driven model is forced by the solar activity and CO2 concentration signals. We find the persistent antiphasing relationship between the solar forcing and Niño-3.4 SST on the bicentennial time scale. The dynamical mechanism of such a response is discussed.

The work was supported by the Russian Science Foundation (Grant No. 20-62-46056)

1. Emile-Geay, J., Cobb, K. M., Mann, M. E., & Wittenberg, A. T. (2013). Estimating Central Equatorial Pacific SST Variability over the Past Millennium. Part II: Reconstructions and Implications, Journal of Climate, 26(7), 2329-2352.
Dynamical drivers of the 2020 Mei Yu floods over China
Authors: Muetzelfeldt Mark , Volonté Ambrogio , Schiemann Reinhard , Turner Andrew , Klingaman Nicholas
Published: March 2021

Large parts of East and South Asia were affected by heavy precipitation and flooding during early summer 2020. This study provides both a statistical and dynamical characterisation of these events. By aggregating daily and monthly precipitation over river basins across Asia, it is shown that the Yangtze River Basin (YRB) is one of the areas that was particularly affected. June and July 2020 rainfalls were higher than in the previous 20 years, and the YRB experienced anomalously high rainfall across most of its sub-basins. An automated method detecting the daily position of the East Asian Summer Monsoon Front (EASMF) is applied to show that the anomalously high YRB precipitation was associated with an anomalously slow northward progression of the EASMF and prolonged Mei Yu conditions over the YRB lasting more than one month. Lagrangian trajectory analysis is employed to study the convergence of air masses in the EASMF during two 5-day heavy-precipitation episodes, 12-16 June and 4-8 July 2020. Despite heavy precipitation and the convergence of monsoonal and subtropical air masses seen in both episodes, clear differences are identified between these episodes in the location/strength of the Subtropical Westerly Jet and the location of the Western North Pacific Subtropical High. This study contextualises heavy precipitation in Asia in summer 2020 and showcases a number of analysis tools developed by the authors for the study of such events.