bluuebunny/crossref_metadata_2025 huggingface dataset:
Satellite-based estimate of the climate forcing due to aerosol - ice cloud interactions
Authors: Sourdeval Odran , Gryspeerdt Edward , Mülmenstädt Johannes , Krämer Martina , Quaas Johannes
Published: March 2020

Substantial efforts have been led over the last decades to improve our understanding of the interactions between clouds and anthropogenic aerosols (aci). The effective radiative forcing associated with these interactions (ERFaci), which combines the radiative forcing (i.e. Twomey effect) and cloud adjustments, still constitutes a large part of our current uncertainties on climate predictions.

Important progress has been made in the assessment of ERFaci for liquid clouds, partly due to advances in the joint use of satellite and modelling data to tackle this problem. More particularly, the retrieval of the droplet number concentration from satellite remote sensing - a property closely related to droplet nucleation processes - has been extremely helpful to better quantify ERFaci. However, similar estimations for ice clouds have for long suffered from a lack of observational constraint on the ice crystal number concentration (Ni), a challenging task due to the high complexity of the physical processes associated with the nucleation and growth of ice crystals. However, a novel long-term global dataset of Ni from active satellite measurements has recently (DARDAR-Nice) opened the door to new observation-based estimates of RFaci for ice clouds.

This study investigates aerosol - ice clouds interactions using Ni profiles from the DARDAR-Nice product together with collocated aerosol information from the Copernicus Atmospheric Monitoring Service (CAMS) reanalyses. A multitude of cloud regimes, subdivided into seasonal and regional bins, are considered in order to disentangle meteorological effects from the aci signature. First results of joint-histograms between Ni and the aerosol mass show an overall positive sensitivity of Ni to the aerosols load. This response is particularly strong towards to cloud-top and flattens towards cloud-base, consistently with expectations for ice nucleation processes. In terms of adjustments, the relation between IWP and Ni is also investigated. Preliminary results suggest a slightly negative global ERFaci for ice clouds, with important regional variations, but a precise quantifications of these effects will require further statistics.
Subsurface imaging with electrokinetically-induced seismoelectric signals generated by low-frequency seismic waves
Authors: Alekseev Dmitry , Gokhberg Mikhail , Pliss Aleksandra , Goncharov Aleksey , Veklich Ilya
Published: March 2020

In this study we focus on the coupled macroscopic description of the second-kind seismo-electric (SE) effect in the subsurface structure arising due to low-frequency seismic waves. Starting with the Biot poroelasticity model, we derive the equations of the coupled geomechanical-electromagnetic problem assuming mechanical excitation in the form of seismic waves (primarily Rayleigh waves), and create code for seismoelectric field simulation. We present the results of the feasibility study showing the promising possibilities for determination of non-uniform subsurface structure parameters and allowing a subsurface imaging in terms of rock elastic constants, conductivity and permeability.

The study was supported by the Russian Foundation for Basic Research (Project No. 20-05-00691).
Hydrographic changes across the Atlantic Ocean on interannual to decadal time scales – an EN4 profile data analysis
Authors: Burmeister Kristin , Inall Mark , Johnson Clare
Published: March 2020

The Atlantic Ocean is influenced by large-scale physical variability like changes in the Subpolar Gyre (SPG), the Atlantic Multidecadal Variability (AMV), the Atlantic Meridional Mode (AMM) or changes in the South Atlantic Anticyclone (SAA). Associated changes in temperature and salinity may severely impact open-ocean and deep-sea ecosystems. We study the variability of potential temperature and salinity profiles associated with large-scale physical variations focusing on 12 marine regions across both the North and South Atlantic Ocean (subpolar Mid-Atlantic Ridge off Iceland; Rockall Trough to Porcupine Abyssal Plain; central Mid-Atlantic Ridge; northwest Atlantic; Sargasso Sea; eastern tropical North Atlantic; central equatorial Atlantic; ecosystems from Angola to the Congo Lobe; the Benguela Current region; ecosystems off Brazil; the Vitória-Trindade Seamount Chain off Brazil; Malvinas Upwelling Current off Argentina). These regions were selected within the framework of the EU Horizon 2020 iAtlantic project. They are in proximity to major ocean circulation pathways as well as ocean monitoring arrays and are important for international conservation, Blue Growth and Blue Economy attempts.

Our methodology builds on recent work (Johnson et al., accepted, Frontiers in Marine Science) that shows that climate indices are associated with statistically-significant and spatially-coherent changes in bottom conditions across the northern North Atlantic. We use the same composite approach to investigate the relationship between indices of physical variability and potential temperature and salinity but extend the analysis to include additional indices (e.g. AMM, SAA) and to cover the entire Atlantic basin. Additionally, we use profile data instead of a gridded data product and investigate the full water column by density class, rather than focusing on bottom conditions. This enables physical mechanisms of any observed signals across the Atlantic Ocean as a whole to be explored.
K and Ti metasomatism of the mantle wedge by fluids under sub-arc conditions
Authors: Sverjensky Dimitri , Matthews Simon
Published: March 2020

It is well documented that subducting slabs influence arc volcanics. Slab components are transferred to the mantle wedge by fluids and/or melts. Aqueous fluids released from the slab are thought to trigger partial melting in the mantle wedge and potentially influence the chemistry of the lavas that erupt in island arcs. Both fluids and melts from the slab have been proposed to transfer chemical elements to the mantle wedge. However, exactly how this occurs chemically and physically remains unclear. Recent progress in developing a Deep Earth Water model calibrated with experimental mineral and rock solubility data under sub-arc conditions now enables the chemical mass transfer from slab to mantle wedge to be predicted for comparison with natural samples.

            We report a new aqueous speciation model for Ti-species calibrated with experimental data Kessel and co-workers and Antignano and Manning that includes a neutral Ti-OH species, a Na-Ti-silicate anion, and a Ti-silicate-bicarbonate anion. The Ti-OH species is only important in almost pure water. However, the Na-Ti-silicate anion is important in high-silica fluids (e.g. in equilibrium with quartz or coesite-bearing mafic eclogites) but is overtaken in importance by the Ti-silicate-bicarbonate complex in CO2-bearing fluids.

            In the present study, we modeled the metasomatic reactions when a fluid in equilibrium with a mafic eclogite leaves a subducting slab and encounters lherzolite in the overlying mantle wedge. Initially, the mafic eclogitic fluid was in equilibrium with clinopyroxene, garnet, coesite, diamond, magnesite solid-solution, and rutile at 700°C and 4.0 GPa. Whilst the presence of CO2 enables the modelled fluid to carry 600 mg/kg H2O of nominally immobile Ti from the slab into the wedge, the fluid transports a factor of 30 more K. The fluid was then heated to 950°C and simultaneously reacted irreversibly with lherzolite containing 0.86 wt% K2O and 0.084 wt% TiO2. The resultant metasomatized peridotite consisted of olivine, orthopyroxene, clinopyroxene, and garnet to which phlogopite-rich biotite had been added, and from which the TiO2 component was subtracted. Overall, the metasomatism resulted in K-enrichment and Ti-depletion in the metasomatized part of the mantle wedge. The final fluid was enriched in Ti (2,830 mg/kg H2O) with lowered K (11,600 mg/kg H2O). Both the remaining fluid and metasomatized mantle may serve as sources of the elevated K/Ti ratios in arc volcanics relative to MORB.
Challenges and opportunities of quantifying local CO2 advection at a mountain forest in the Alps
Authors: Galvagno Marta , Wohlfahrt Georg , Zhao Peng , Cremonese Edoardo , Filippa Gianluca
Published: March 2020

Mountain forests, which play an important role in the mitigation of anthropogenic CO2 emissions are supposed to be heavily affected by climatic changes and extremes. Efforts towards the understanding of the physiological processes regulating mountain forest carbon and water fluxes are crucial to correctly manage and protect these key ecosystems. However, among the challenges in micrometeorological flux measurements in complex terrain, the unaccounted presence of advective CO2 fluxes has the potential to bias the daily and longer-term CO2 exchange estimates towards unrealistic net uptake, a bias that urgently needs to be accounted for in order to reduce uncertainties related to role of mountain forests in the global carbon cycle. On the other hand, given the typical local bi-directional wind system in mountains, information on advective flows at these sites could be easier to detect compared to other terrains. We present the results of a CO2 advection experiment conducted at a European larch site in Northern Italy (2100 m asl). The setup consisted of: the main eddy covariance flux tower (20 m), a sub-canopy eddy covariance flux system (2 m), a home-assembled system for measuring CO2 concentrations at three heights on the four sides of a 40 x 40 m control volume, composed by a solenoid valve system, multiple sampling inlets and a gas analyzer, and three automatic chambers measuring bare soil respiration (two chambers) and the net ecosystem CO2 exchange from the vegetated forest floor (one chamber). Results show that: i) advection is a not-negligible fraction of the total net ecosystem CO2 exchange of this forest, ii) coupling measurements of above and below canopy eddy covariance in mountain forest sites could emerge essential for detecting/estimating the unaccounted CO2 flux
Model study on effect of hematite and goethite on optical properties of inhomogeneous desert dust aerosols
Authors: Gasteiger Josef , Gattringer Andreas , Weinzierl Bernadett
Published: March 2020

Desert dust aerosols occur as complex ensembles of particles with irregular shapes. Furthermore, these particles consist of a variety of different minerals which often coexist next to each other within individual particles. While in recent years the nonsphericity of particles is considered more and more in optical models of desert dust, the mineralogical inhomogeneity is still rarely considered though it can have a significant effect on light scattering and absorption.

Is this study, we discuss optical properties of irregularly-shaped inhomogeneous dust particles which were modelled with a Discrete Dipole Approximation code. We show how absorbing inclusions embedded in a non-absorbing material affect absorption and scattering by a particle as compared to the case when all the absorbing material is homogeneously distributed inside the particle. Hematite and goethite were selected as the material of the absorbing inclusions since these minerals are known to be responsible for most of the light absorption in desert dust aerosols.
Exploring the control of phenological patterns of leaf function and tree growth in European tree species
Authors: Arend Matthias , Zahnd Cedric , Hoch Günter
Published: March 2020

Trees in temperate climates show distinct seasonality of leaf photosynthetic function and tree growth, which has strong influence on the annual cycle of terrestrial carbon sequestration. Thus, there are intense efforts to explore phenological pattern of leaf photosynthetic function and tree growth in temperate tree species and understand their internal and external regulation. In this presentation, we summarize our past research in this field, combining results from different experimental studies and field observations on a large number of European tree species. We show not only the well-known dependency of the onset of spring bud burst and leaf development on temperature and photoperiod and their large inter- and intra-specific variability, but also refer to further, fairly unknown, environmental factors. We give examples how varying soil properties and drought stress may interact with temperature on the seasonal timing of bud burst, photosynthesis, shoot growth and autumnal leaf senescence. Finally, we give information on the temporal coordination of bud burst, canopy greening and tree growth, showing strong differences among European tree species. With the collected information, we identify potential sources of uncertainty in approaches predicting the seasonal timing of leaf photosynthetic activity and tree growth with climate warming.

 
Sub-seasonal prediction of Arctic sea ice concentration using time series forecasting technique
Authors: Kim Baek-Min , Kim Ha-Rim , Choi Yong-Sang , Lee Yejin , Yang Gun-Hwan
Published: March 2020

Recently, many studies have highlighted the importance of the ability to predict the Arctic sea ice concentration in the sub-seasonal time scales. Notably, the Arctic sea ice concentration has a potential for skillful predictions through their long-term trend memory. Based on the long-term memory of Arctic sea ice concentration, we evaluate the predictability of Arctic sea ice concentration (SIC) by applying a time-series analysis technique of the Prophet model on sub-seasonal time scales. A Prophet is a recently introduced method as a statistical approach inspired by the nature of time series forecasted at Facebook and has not been applied to the prediction of Arctic SIC before. Sub-seasonal prediction skills of Arctic SIC in the Prophet model were compared with the NCEP Climate Forecast System Reforecast (CFS-Reforecast) model as a dynamical approach and verified with the satellite observation during wintertime from 2000 to 2018 for 1 to 8 weeks lead times. The result shows that the Prophet model exhibits much better skill than the NCEP CFS-Reforecast model in the climatology prediction except for the 1 to 3 weeks lead times, as the Prophet model has mainly the ability to capture the long-term trend. In the anomaly prediction, however, the NCEP CFS-Reforecast model is superior to the Prophet model in the prediction of sub-seasonal time scales, as the NCEP CFS-Reforecast captures more effectively the sub-seasonal transition of the underlying dynamical system. Therefore, even if the Prophet model has shown a useful skill in predicting the climatological Arctic SIC, there is still a need to improve the accuracy and robustness of the predictions in an anomalous Arctic SIC. Further, we suggest that the bias correction method is needed to improve the forecast skill of Arctic SIC using the time-series analysis technique, and it will be critical to advance the field of the Arctic SIC forecasting on the sub-seasonal time scales.
Unraveling the time-scale teleconnections between soil moisture and vegetation
Authors: Bueso Diego , Piles Maria , Camps-Valls Gustau
Published: March 2020

Identifying causal relations from observational data is key to understand Earth system interactions. Extensions to spatio-temporal analysis at different scales are of vital importance for better understanding dynamical phenomenon of natural complex systems. Soil moisture-vegetation interactions constitute a central part of ecosystem functioning and health. Here we are interested in uncovering (potentially nonlinear) spatio-temporal causal relations at different time scales between two relevant Earth observation variables: soil moisture (SM) and vegetation optical depth (VOD). To aboard the complexity data problem, we extract relevant and expressive feature components with the nonlinear kernel-based dimensional reduction method ROCK-PCA in [1]. The method yields the main modes of variability of the variables that are then used to study causal relations. To infer causality relations we use the cross-information kernel Granger causality (XKGC) method introduced in [2], which accounts for nonlinear cross-relations between the involved variables and generalizes nonlinear GC methods. Results are succesfully compared to standard correlation analysis, transfer entropy and convergent cross-mapping alternative methods. In general XKGC identifies a sparser connectivity than correlation. Also, well-known wet and dry patterns are identified as reported in the literature, but other interesting unreported connections and spatio-temporal SM<-->VOD emerge.

REFERENCES
[1] D. Bueso, M. Piles and G. Camps-Valls, "Nonlinear PCA for Spatio-Temporal Analysis of
Earth Observation Data," in IEEE Transactions on Geoscience and Remote Sensing, accepted (2020).
[2] Brajard, J., Charantonis, A., Chen, C., & Runge, J. (Eds.). (2019). Proceedings of the
9th International Workshop on Climate Informatics: CI 2019 (No. NCAR/TN-561+PROC).
Scale dependency of segmentation along the strike of normal faults.
Authors: Roche Vincent , Manzocchi Tom , Camanni Giovanni , Childs Conrad , Papanikolaou Vasileios
Published: March 2020

The present study provides insights on the segmented nature of normal faults as a function of scale, and attempts to identify whether segmentation is scale invariant, scale dependent or hierarchical. This is a topic of critical importance for studies of fault development and in modelling exercises where one needs to extrapolate observations at one scale to other scales. 

Results are based on data observed in the Blue Lias in Somerset (UK), in Fumanya mine (Spain) and in a 3D seismic reflection survey in the Bonaparte Basin (Australia). Fault segmentation is investigated quantitatively based on previously established methodologies and we focus on neutral relay zones observed between fault segments along the strike of the normal faults.

We found that there are quantitative indications that the shape of the relay zones, the breaching of the relays and the degree of segmentation are all scale independent in Kilve and Fumanya. We propose that this is related to the low variability across scales in the geological parameters controlling segmentation, due to the relative homogeneity of the rock medium across the studied scales, the lack of influence of pre-existing faults or fractures, and the similar deformation histories for all studied faults. By contrast, faults show scale dependency in the Bonaparte Basin where large faults are under the influence of an oblique reactivation of pre-existing faults. Independently of the area, segmentation observed continuously through scale stresses the need to take into account resolution of observation in discussing fault development.
Coupled processes in clay during tunnel excavation
Authors: Rinaldi Antonio Pio , Guglielmi Yves , Zappone Alba , Soom Florian , Robertson Michelle , Cook Paul , Kakurina Maria , Wenning Quinn , Rebscher Dorothee , Nussbaum Christophe
Published: March 2020

Tunnel excavations are known to perturb the hosting rock mass at long distances, with changes in the hydrogeological flow affecting, as well as deforming the rock mass, inducing subsidence in a zone above the tunnel. During the extension of the Mont Terri Underground Rock Laboratory, we had the unique opportunity to monitor the final part of the excavation of Gallery18 and the final breaktrough.

The joint effort of two experiments (CS-D lead by ETH Zurich and FS-B lead by LBNL) allowed for a detailed characterization of the poro-elastic response of the rock mass and the Mont Terri Main Fault Zone to the excavation. Geophysical, geomechanical, and hydrogeological monitoring include: (1) pressure monitoring in several borehole intervals; (2) deformation at a chain potentiometer and fiber optics grouted in boreholes (normal to bedding and parallel to fault zone), and platform-tilmeters installed at the tunnel floor, as well as detailed 3D displacement at the SIMFIP probe.

All monitoring systems detected major perturbations starting from 15 days before the breakthrough and continuing for several days after it. We summarize the observations and will combine numerical modelling and observed trend to conceptualized the pattern of poro-elastic deformation. The results of the analysis could help shedding light on the poro-elastic behaviour of clay, providing interesting hints for the modeling community and helping in planning of future nuclear waste repositories in such material.
Influence of size and mixing state on the wet scavenging of black carbon aerosol in the North China Plain
Authors: Pan Xihao , Ma Nan , Zhou Yaqing , Zhu Shaowen , Peng Long , Li Guo , Zhang Yuxuan , Tao Jiangchuan , Bi Xinhui , Zhang Qiang , Su Hang , Cheng Yafang
Published: March 2020

Black carbon (BC) is the most important light-absorbing species in the atmosphere and has a strong positive direct radiative forcing. In-cloud scavenging is the major way to wash out BC from the atmosphere. Understanding the connection between its physico-chemical properties and scavenging efficiency is therefore a key to evaluate its lifetime, atmospheric burden and spatial distribution. During an intensive field campaign conducted in the North China Plain in 2019, a ground-based counterflow virtual impactor was utilized to separate fog droplets in radiation fog events. BC mass and mixing state of fog droplet residues were online measured with a single particle soot photometer (SP2). In a strong radiation fog event with visibility of about 50 m, more than 20% fog droplets are found to contain a BC core. BC scavenging efficiency is found to be strongly determined by its diameter and mixing state. Driven by different mechanisms, higher scavenging efficiencies up to 10% are observed for larger and smaller BC particles, and the minimum efficiency is found at BC diameter of 120 nm. For large core (>120 nm) BC-containing particles, the scavenging efficiency increases significantly with coating thickness (CT), from about 10% for CT<100 nm to 80% for CT>300 nm. Chemical composition may also be a key parameter influencing the scavenging of BC. Based on the observation of 3 fog events, parameterizations of BC scavenging efficiency are also given in this study.
Characterization of the water flow regime in the upper vadose zone, Furtowischacht (Hochschwab, Austria)
Authors: Kaminsky Eva-Florina , Plan Lukas , Wagner Thomas
Published: March 2020

The Kläfferquellen as the largest springs in the north of the Hochschwab karst massif are an important source of drinking water for the city of Vienna. Due to the vulnerability of karst waters, parts of the Hochschwab Massive (80 km southwest of Vienna) are a spring water protection zone. A better understanding of the karst aquifer recharge is important for the karst water protection management. The upper zone of a karst aquifer, the epikarst plays an important role for the recharge and the regulation of water flow to the vadose zone below.

Hydrological monitoring in an Alpine vadose shaft (Furtowischacht) is the basis of these analyses. In order to quantify the water storage and flow in the upper vadose zone, a Thomson-weir was installed in a small canyon at 100 m below the entrance. Since 2016, electrical conductivity (EC), temperature (T) and water level have been measured at the weir at least every 10 minutes. The discharge shows extreme fluctuations between 0.003 to 19 l/s. Salt tracer experiments indicate tracer travel times between 10 min and 3 hours. The discharge behaviour after a precipitation event can be classified with hydrograph recession analysis in quick, intermediate and slow flow.  Snow melting events show intermediate and slow responses. The water storage within the epikarst can be inferred from the following observations: (1) Reactions of T and EC after the increase of discharge vary between 10 min and 5 h. (2) During summer rain events, EC increases (after a short decrease) and remains at an elevated level for longer period of time. (3) No drying up of the cave brook after long periods of no recharge, where baseflow shows a storage capacity. Single discharge events were successfully modelled with a bucket-type rainfall-runoff model thereby describing the water flow and storage in the upper vadose zone, respectively.
The development of a laboratory drip rig for performing reproducible comparisons on different precipitation sensors by correcting for environmental conditions and rig set up
Authors: Frame Ginger , Spencer Erin
Published: March 2020

Assessing the accuracy of precipitation sensors can prove very challenging due to the lack of a universal test standard, stemming from difficulties in creating a controlled test scenario. We propose a refined method of testing that is highly reproducible and can be applied to any precipitation sensor regardless of sensing technology.

It is widely understood that two identical disdrometers mounted close together in a real rain event are not likely to report the same precipitation measurements due to the small scale spatial variation of rain. This makes it difficult to draw comparisons between sensors of the same type and even more difficult to compare rain sensors that have different sensing areas and use different sensing technologies. It is therefore desirable to simulate rainfall in the laboratory that is representative of real world conditions but this presents its own set of challenges, primarily in creating rain drops that travel at terminal velocity. This test method significantly reduces the impact of this issue.

This is particularly important for sensors such as optical, acoustic, radar or impact, where the calculations used to obtain rainfall accumulation and drop size distribution assume that the droplets are at terminal velocity. Even for sensors such as capacitive rain gauges and tipping buckets, where the velocity of fall is not directly related to the measurements, more valid conclusions can be drawn about the sensor’s ability to measure precipitation when the droplets imitate real rainfall as closely as possible.

Here, the development of a drip rig capable of creating raindrops of a controlled size is documented. The drip rig can be mounted at a known height and used to test a variety of different precipitation sensors. However, due to height restrictions in the laboratory, it is not possible to get larger raindrops to terminal velocity. Mounted at a height of 7.4m, drops above 2 mm in diameter do not reach 99% terminal velocity, and drops above 3 mm do not reach 95%. For this reason, corrections must be applied to the calculations. It is therefore essential to have an understanding of the change in fall velocity of a water droplet with fall distance.

This work documents the equations used to calculate drop velocity with fall distance for different drop masses. Temperature, humidity and air pressure define air density, which has a significant impact on the velocity of a falling water droplet. The effect of each of these environmental factors has been investigated in order to allow for further corrections. Performing these corrections greatly improves the validity and repeatability of the tests carried out on precipitation sensors.
Climate change impact evaluation in various regions in Europe on the base of ensemble modelling
Authors: Krzyszczak Jaromir , Baranowski Piotr , Zubik Monika
Published: March 2020

Climate change uncertainty largely complicates adaptation and risk management evaluation at the regional level, therefore new approaches for managing this uncertainty are still being developed. In this study three crop models (DNDC, WOFOST and DSSAT) were used to explore the utility of impact response surfaces (IRS) and adaptation response surfaces (ARS) methodologies (Pirttioja et al., 2015; Ruiz-Ramos et al., 2018).

To build IRS, the sensitivity of modelled yield to systematic increments of changes in temperature (-1 to +6°C) and precipitation (-30 to +50%) was tested by modifying values of baseline (1981 to 2010) daily weather. Four levels of CO2 (360, 447, 522 and 601 ppm) representing future conditions until 2070 were considered. In turn, to build ARS, adaptation options were: shortening or extending the crop cycle of the standard cultivar, sowing earlier or later than the standard date and additional irrigation. Preliminary data indicate that yields are declining with higher temperatures and decreased precipitation. Yield is more sensitive to changes in baseline temperature values and much less sensitive to changes in baseline precipitation values for arable fields in Finland, while for arable fields in Germany, ARS indicates yield sensitivity at a similar level for both variables. Also, our data suggests that some adaptation options provides increase of the yield up to 1500 kg/ha, which suggest that ARSs may be valuable tool for planning an effective adaptation treatments. This research shows how to analyze and assess the impact of adaptation strategies in the context of the high level of regional uncertainty in relation to future climate conditions. Developed methodology can be applied to other climatic zones to help in planning adaptation and mitigation strategies.

This study has been partly financed from the funds of the Polish National Centre for Research and Development in frame of the project: MSINiN, contract number: BIOSTRATEG3/343547/8/NCBR/2017
Present Seismotectonic Behavior of the EAF from Improved Seismicity Catalog and Earthquake Source Mechanism Solutions
Authors: Guvercin Sezim Ezgi , Karabulut Hayrullah , Dogan Ugur , Cakir Ziyadin , Ergintav Semih , Zabci Cengiz , Ozdemir Alpay , Ozarpaci Seda , Konca Ali Ozgun , Kokum Mehmet
Published: March 2020

The seismotectonic behavior of the Eastern Anatolia is predominantly controlled by the East Anatolian Fault (EAF). Together with the North Anatolian Fault (NAF), this ~400 km long sinistral transform fault, accommodates the westward motion of Anatolia between Anatolian and Arabian plates with a slip rate of ~10 mm/yr which is significantly slower than the motion of the NAF (25 mm/yr). Although this two major faults are similar in terms of the migration of the large earthquakes from east to west, the present seismicity of the EAF is high compared to the NAF. Except for the several earthquakes with Mw > 5, there were no devastating earthquakes during the instrumental period along the EAF. The absence of large earthquakes during the last ~50 years along the EAF indicates presence of significant seismic gaps and potential seismic hazard in the region. Recent studies indicate segmentation of the EAF with varying lengths of creeping and locked segments. Some details of the geometries and the slip rates of these segments have been estimated by the InSAR observations. Both InSAR and GPS observations indicate that the maximum creep along this the EAF is ~10 mm/yr, approximately the slip rate of the EAF.

While both geodetic data verify the existence of creep from surface deformation, its relation to the seismic behavior of the EAF is less clear. There is a ~30 km long creeping segment to the north-east of Lake Hazar which generates no significant seismicity. On the other hand, another creeping segment to the south-west of Lake Hazar, there are repeating events, below the depth of 10 km, with a horizontal extent of 15 km. The highly fractured and complex structure of this fault zone is also confirmed by the available focal mechanisms which shows significant variety.

In this study, we update seismicity catalog with improved locations to date and present a uniform and high quality focal mechanism catalog down to M4 completeness, using regional waveforms. The seismicity catalog is used to estimate the geometry of the segmentation while the novel earthquake source mechanisms are used to understand the kinematics of the segments and interactions. Moreover, we present the latest M4.9, 2019, Sivrice earthquake, pointing out a location where the stress is perturbed due to a transition from creeping segment to locked segment. (Supported by TUBITAK no: 118Y435 project)
Reducing the impact of extreme environmental factors on berry plantations
Authors: Zagyvai-Kiss Katalin Anita , Csáki Péter , Kalicz Péter , Szőke Előd , Varga Jenő , Zagyvai Gergely , Gribovszki Zoltán
Published: March 2020

Climate extremes affect the vitality and health of the berry species. In some regions, if enough water is available, the impacts can be reduced. Long-lasting stress effect causes sunscald in case of leaves and berries. There are resistant and susceptible varieties of berry species. The disorder, likely caused by ultra-violet radiation, appears on susceptible varieties when the temperature suddenly increases (above about 30 °C), but the humidity is low. It can easily occur in the presence of wind.

Agroforestry systems offer a possible way to reduce direct sunlight by shading to sensitive agricultural crops. The humidity of the tree canopy can decrease the effect of hot dry air. Trees protect the berry species by slowing wind speed. This ongoing research focuses on how trees can influence the hydrological conditions.

We installed a research plot to study the spatial and temporal variability of soil moisture and groundwater level in an agroforestry system compared with agricultural field without trees (Fertőd, Hungary). The measurement is completed with local climatic parameters such as precipitation, air temperature, and relative humidity. The species of the measured plots are blackberry (Rubus fruticosus ‘Dirksen’), raspberry (Rubus idaeus ‘Fertődi zamatos’), and blackcurrant (Ribes nigrum ‘Otelo’) with integrated shadowing trees: hybrid poplar (Populus x euramericana).

Acknowledgements: The project was supported by EFOP-3.6.2-16-2017-00018 for the University of Sopron.
Geomorphological and hydrological characterization of a meandering river by UAV and UWV applications
Authors: Bertalan László , Sardemann Hannes , Mader David , Szopos Noémi Mária , Nagy Bálint , Eltner Anette
Published: March 2020

The Sajó River in Hungary is a medium-sized sand-bed river along which intensive meander development and bank erosion occur. The process threatens agricultural lands and populated areas extensively.  Therefore, preventive river management is needed.

Main geomorphological features, processes and in-channel flow conditions have to be studied in detail in order to reveal main driving factors. Datasets with high spatio-temporal resolution are necessary to identify relevant parameters. However, so far data density at this river is sparse and gauging stations are distributed poorly.

The aim of this study is the improvement of data availability to measure and model hydromorphodynamics of single reaches of the Sajó River. Therefore, multi-temporal field campaigns along selected sub-reaches are conducted with Unmanned Aerial Vehicles (UAV) and Unmanned Water Vehicles (UWV) to survey the topography, the river bed and flow conditions. The channel bathymetry is measured by a single-beam echo sounder mounted on a self-designed remotely controlled boat. The boat also integrates a Mobile Laser Scanner (MLS) to measure the river banks. Furthermore, a panorama camera system is installed to improve the pose estimation of the UWV functioning as a calibrated multi-sensor platform. UAV surveys were performed, using RGB and Thermal Infrared image sequences, to apply image velocimetry algorithms to characterize the river flow at selected cross-sections.  ADCP measurements and Terrestrial Laser Scans (TLS) are used for accuracy assessment of the novel datasets.

Eventually, data captured over a 2-years period will be implemented into hydrodynamic modeling of the studied sub-reaches to better understand seasonal variations in channel morphodynamics.

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The project has been founded by the DAAD (57448822) and (Tempus Public Foundation & DAAD 307670). The research is also influenced by the HARMONIOUS COST Action (CA16219).
Satellite-derived spatiotemporal patterns of environmental changes caused by 2018-2019 wildfires in Arctic-Boreal Russia
Authors: Cherepanova Elena , Bondur Valery , Zamshin Viktor , Feoktistova Natalia
Published: March 2020

Forest fires affect environmental changes both directly, changing the type of land cover, causing local and regional air pollution through emissions of greenhouse gases and aerosols, and indirectly through a secondary effect on atmospheric, soil and hydrological processes. The increase in the number and area of uncontrolled wildfires, the degradation of permafrost in high latitude areas leads to a change in the balance of greenhouse gases in the atmosphere, and it results in the negative impact on the Earth’s climatic system.

This study examined the Arctic-Boreal territories of the Russian Federation, where huge forest fires were observed in 2018-2019. In most of these areas, forest fire detection is carried out only by means of the satellite monitoring without aviation support. The sparsely populated and inaccessible territories are a major factor of the rapid spread of fires over large areas. Most of the forest areas in the region are so-called control zones, where the authorities may decide not to extinguish the fires if they do not threaten settlements and economic facilities, and consider the salvation of forests economically unprofitable. However, there is no reliable data on the environmental consequences of large forest fires in the Arctic-Boreal territories.

Satellite monitoring of wildfires provides the detection of fire locations, an assessment of their area and burning time. In our study, we used various indices calculated from remote sensing data for the pre-fire and post-fire periods to identify the spatiotemporal patterns of environmental change caused by large wildfires. The Sentinel 5 TROPOMI time series have been analyzed for the short-term and long-term atmospheric composition anomalies detection caused by forest fires in the region. In the process of comparing the methane concentrations time series for the 2018- 2019 fire seasons the constantly high values anomaly zones were found. We believe that these anomalies are resulting from Sentinel-5 CH4 algorithm constrains, which requires additional work on data validation with relation to the local conditions.

The reported study was funded by RFBR, MOST (China) and DST (India) according to the research project № 19-55-80021
Linking weather types to tense dewatering situations of the Kiel Canal (NOK)
Authors: Jensen Corinna , Möller Jens , Löwe Peter
Published: March 2020

Within the “Network of experts” of the German Federal Ministry of Transport and Digital Infrastructure (BMVI), the effect of climate change on infrastructure is investigated. One aspect of this project is the future dewatering situation of the Kiel Canal (“Nord-Ostsee-Kanal” (NOK)). The Kiel Canal is one of the world’s busiest man-made waterways navigable by seagoing ships. It connects the North Sea to the Baltic Sea and can save the ships hundreds of kilometers of distance. With a total annual sum of transferred cargo of up to 100 million tons it is an economically very important transportation way. Additionally to the transportation of cargo, the canal is also used to discharge water from smaller rivers as well as drainage of a catchments area of about 1500 km².

The canal can only operate in a certain water level range. If its water level exceeds the maximum level, the water must be drained into the sea. In 90% of the time, the water is drained into the North Sea during time windows with low tide. If the water level outside of the canal is too high, drainage is not possible and the canal traffic has to be reduced or, in extreme cases, shut down. Due to the expected sea level rise, the potential time windows for dewatering are decreasing in the future. With a decrease in operational hours, there will be substantial economic losses as well as an increase in traffic around Denmark.

To get a better understanding of what causes tense dewatering situations other than sea level rise a linkage between high water levels on the outside of the canal and weather types is made. Weather types describe large-scale circulation patterns and can therefore give an estimate on tracks of low-pressure systems as well as the prevailing winds, which can explain surges and water levels at the coast. This analysis is conducted for one weather type classification method based solely on sea level pressure fields. Weather types derived from regionally coupled climate models as well as reanalyses are investigated.
Four years of soil strain monitoring on Etna Volcano Mount by means of a Three-axial Fiber Bragg Grating Sensor
Authors: Giacomelli Umberto , Maccioni Enrico , Carelli Giorgio , Carbone Daniele , Gambino Salvatore , Orazi Massimo , Peluso Rosario , Sorrentino Fiodor
Published: March 2020

Rock strains detection is one of the principal ways to monitor geohazards. Classic strainmeters are cumbersome, hard to install and very expensive. Opto-electronics devices based on fiber Bragg grating technology allow to realize strainmeters with high sensitivity, low-cost, small volume and high performance.
We present the long term result of continuous soil strain monitoring on the Etna mount by a three-axial fiber Bragg grating sensor. The sensor has been developed in the framework of European Project MED-SUV (MEDiterranean SUpersite Volcanos). The installation site is a 8.5 meters deep borehole at a distance of about 7 km South-West from the summit craters of the Etna mount, at an elevation of about 1740 meters. This kind of sensor has a resolution better than 100 nanostrains on a daily timescale. Despite it is only a prototype, the sensor has worked for four years with a duty-cycle higher than 90% detecting both fast event, as earthquakes, and slow event, as epochal rocks strain behavior.
Properties and Generation of Large Scale Travelling Ionospheric Disturbances during 8 September 2017
Authors: Borries Claudia , Ferreira Arthur Amaral , Xiong Chao , Borges Renato Alves , Mielich Jens , Kouba Daniel
Published: March 2020

Large Scale Travelling Ionospheric Disturbances (LSTIDs) are a frequent phenomenon during ionospheric storms, indicating strong electrodynamic processes in high latitudes. LSTIDs are signatures of Atmospheric Gravity Waves (AGW) observed in the changes of the electron density in the ionosphere. During ionospheric storms, large scale AGWs are often generated in the vicinity of the auroral region, where sudden strong heating processes take place.

Many LSTIDs are observed during the ionosphere storm during the September 2017 Space Weather event. In this presentation, the LSTID occurrence on 8th September 2017 is analysed in more detail, based on a TID detection method using ground based Global Navigation Satellite System (GNSS) measurements. Fast LSTIDs are observed in midlatitudes between 0-3 UT and 13-16 UT. Slow LSTIDs are observed between 3-12 UT. A significant strong wave-like TEC perturbation occurred in high latitudes at noon, which vanished at around 50°N. A strong single LSTID in mid-latitudes generated in high latitudes around 18 UT. Consulting IMAGE magnetometer data, ionosonde measurements and Swarm field aligned current measurements, strong heating processes, the extension of the Auroral oval and unusual electrodynamic processes are discussed as source mechanisms for these LSTIDs.
DOM biodegradability assessed in a land covering lake survey in Norway: does DOM character dominate environmental controls?
Authors: Brecke Gundersen Cathrine , Crapart Camille Marie , Garmo Øyvind Aaberg , Austnes Kari , Vogt Rolf David , de Wit Heleen
Published: March 2020

Biodegradability of DOM is controlled by both external environmental factors and by DOM character itself. Currently in the literature, more emphasis is being placed on the role of environmental parameters, and the idea of refractory molecules is being challenged. Biodegradation is the most important transformation process for DOM in lakes and has implications such as fuelling the lower food-web with energy/carbon and producing greenhouse gases. To be able to predict ecological responses to future climatic conditions, a better understanding of the controlling factors of DOM biodegradability is needed.  

Here, we present a unique dataset on lake DOM characteristics from an extensive land-covering survey form Norway. The total of 333 different lakes included cover different catchment types such as lowland boreal forests, coastal impacted areas, alpine mountains, and arctic conditions, and with a wide range in catchment-to-lake ratios. The samples were collected using helicopter during the autumn of 2019, just after water mixing, and the samples were analysed immediately upon arrival at the laboratory. The lakes range in TOC concentration from 0.25 to more than 25 mg L-1.

Principal DOM characterisation methods included the acquisition of fluorescence excitation-emission matrices in combination with parallel factor analysis (EEM-PARAFAC) and the assessment of intrinsic DOM biodegradability. The latter was determined by measuring O2 consumption during 24 h using a batch experimental setup, after re-inoculating filtered (0.2 µm) lake DOM samples with a standard environmental inoculum.

The aim of this study is, by contributing with unique spatial data, to reveal the controlling factors of DOM biodegradability in lakes. The measured DOM biodegradability will be linked to structural information of the DOM molecules, extracted from the EEMs, and to environmental parameters such as water chemistry, local climatic conditions, and other catchment characteristics.
Decreasing trends of nitrogen export to waters in tile-drained landscapes are linked to a shifting water balance
Authors: Bauwe Andreas , Kahle Petra , Tiemeyer Bärbel , Lennartz Bernd
Published: March 2020

In this study, time series over 14 years of climate, stream flow, land management, nitrate-nitrogen (NO3--N) concentrations and losses were analyzed to identify potential drivers for temporal trends at two tile-drained catchments under cropland use in northeastern Germany. Mean annual NO3--N concentrations were 9.7 (drainage plot) and 6.8 mg l-1 (ditch catchment), while mean annual NO3--N losses amounted to 22 and 20 kg ha-1, respectively. Results indicated decreasing trends for discharge, NO3--N concentrations and losses, and N surpluses at both the drainage plot and the ditch catchment scale. However, a significant downward trend was only detected for flow-weighted mean annual NO3--N concentrations of the ditch water. A significant positive relationship between annual discharge and mean annual NO3--N concentrations of the ditch underlines the importance of the hydrologic conditions on the NO3--N concentrations. No direct relationships were found between NO3--N concentrations and N surpluses. We conclude that the decreasing NO3--N concentrations could be primarily attributed to decreasing discharge rates. The possible impact of reduced N surpluses was overridden by the hydrologic conditions in the catchment. The statistically significant downward trend of flow-weighted mean annual NO3--N concentrations in the ditch water suggests, however, a positive effect of reduced N surpluses on stream water quality. Our analysis has further shown that effects of land management aiming at reducing N surpluses might only become visible with a delay of years or even decades.