bluuebunny/crossref_metadata_2025 huggingface dataset:
A GIS Based Model Proposal for Assessing the Transversal Connectivity of Natural Landscapes Along the Urban Rivers in support of NBS
Authors: Hysa Artan
Published: March 2020

This study aims to present a GIS-based method for estimating the transversal connectivity among natural landscape patches along urban rivers within the metropolitan area. The method presented here relies on the transversally connected natural landscape mosaics (TCNLM) model, which is based on a reclassification procedure for landscape patches based on their relative connectivity to the water sources. The identified existing and potential TCNLMs can be considered as focal areas for providing ecosystem services in the metropolitan zone. The raw material of the analytical process is Urban Atlas (UA) land cover data. All phases of the process are modelled in Graphical Modeler in QGIS software. The metropolitan areas of London and Paris are selected as specimens of urban agglomerations along major waterbodies such as Thames and Seine River. The selected cases have considerable similarities and differences among them. Jointly with the results, they provide a comparative ground for a quantitative and qualitative evaluation. The results show that the method is easily reproducible in other European metropolitan areas being developed along watercourses. The presented model brings a rapid method for highlighting the transversal connectivity capacities of the natural landscapes along rivers within the metropolitan area in support of Nature Based Solutions for urban challenges.
Ecotoxicological effects of anthropogenic pressure in semi-enclosed artificial lagoon ecosystems in the Gulf of Aqaba
Authors: Wahsha Mohammad Ahmad , Al-Najjar Tariq
Published: March 2020

Heavy metals are considered to be among the most potent environmental contaminants, and their release into the environment is increasing rapidly since the last decades from various sources and activities and may enter into the environment by a wide range of pathways and processes. They can be translocated, disperse in the environment, and bio-concentrate in aquatic organisms, causing increase ecosystem degradation and leading to biodiversity loss. Furthermore, they may enter the food chain, creating health risks for both humans and animals. This study aimed to evaluate the ecotoxicological effects of anthropogenic pressure in semi-enclosed artificial lagoon ecosystems in the Gulf of Aqaba, Red Sea. Our findings with regard to heavy metal contamination showed that the area is contaminated by significant amounts of several potentially toxic heavy metals (such as Cd, Cr, Cu, and Fe). The anthropic intervention in the area impacted heavily the natural environment. We found that the biological test (lipid peroxidation) was a useful assay for assessing the overall health condition and response (stress level) towards natural and anthropogenic forces in the studied areas. The selected marine organisms (Holothuria atra, Tripneustes gratilla, Ulva lactuca and Halophila stipulacea) have the ability to accumulate several levels of heavy metals in their tissue with different trends of bioaccumulation. Therefore, they can be used as promising bioindicators for such research. The results obtained permit to assess the environmental effects of anthropogenic pressure and can be a useful basis for planning possible remediation projects.
Large-scale alternative detection systems for CRNS
Authors: Köhli Markus , Weimar Jannis , Schmidt Ulrich
Published: March 2020

Cosmic-Ray neutron (CRN) sensors are widely used to determine soil moisture on the hectar scale. Precise measurements, especially in the case of mobile application, demand for neutron detectors with high counting rates and high signal-to-noise ratios. For a long time CRNS instruments have relied on helium-3 as an efficient neutron converter. Its ongoing scarcity demands for technological solutions using alternative converters, which are lithium-6 and boron-10. In order to scale up the method and to reduce costs we recently have developed large-scale neutron detectors including readout electronics and data acquisition systems based on Arduino microcontrollers. These boron-lined detectors shall offer an alternative platform to current Helium-3 based systems and allow for modular instrument designs. Individual shieldings of different segments within the detector introduces the capability of gaining spectral information. This opens the possibility for active signal correction during mobile measurements, where the influence of the constantly changing near-field to the overall signal should be corrected. Furthermore, the signal-to-noise ratio could be increased by combining pulse-height and pulse-length spectra to discriminate between neutrons and other environmental radiation. This novel detector therefore combines high-selective counting electronics with large-scale instrumentation technology. The successful implementation of our design allowed also to build the largest up to now existing CRNS detector. 
Seismic Eruption Catalog of Strokkur Geyser, Iceland
Authors: Eibl Eva P. S. , Hainzl Sebastian , Vesely Nele. I. K. , Walter Thomas R. , Jousset Philippe , Hersir Gylfi P. , Dahm Torsten
Published: March 2020

Geysers are hot springs whose frequency of water eruptions remain poorly understood. We setup a local broadband seismic network for one year at Strokkur geyser, Iceland, and developed an unprecedented catalog of 73,466 eruptions. We detected 50,135 single eruptions, but find that the geyser is also characterized by sets of up to six eruptions in quick succession. The number of single to sextuple eruptions exponentially decreased, while the mean waiting time after an eruption linearly increased (3.7 to 16.4 min). While secondary eruptions within double to sextuple eruptions have smaller mean seismic amplitudes, the amplitude of the first eruption is comparable for all eruption types. We statistically assess and model the eruption frequency assuming discharges proportional to the eruption multiplicity and a constant probability for subsequent events within a multi‐tuple eruption. We conclude that the waiting time after an eruption is predictable, but not the type or amplitude of the next one.
Different pockmark systems and their potential importance for the hydrological and biogeochemical balance of a peri-alpine lake
Authors: Cojean Adeline N.Y. , Bartosiewicz Maciej , Zimmermann Jeremy , Lehmann Moritz F. , Kremer Katrina , Wirth Stefanie B.
Published: March 2020

Pockmarks are crater-like depressions on the floor of oceans and lakes formed by the upward transport of fluids through the unconsolidated sediment column. The fluid flow through marine pockmarks is considered to enhance hydrological and biogeochemical exchanges between the sediments and the water body. While a similar relevance can be expected in lakes, the importance of lacustrine pockmarks in this regard is virtually unexplored.

Lake Thun (48.3 km2 surface area), Switzerland, is an excellent system to study lacustrine pockmarks as it exhibits several sites with different geological and biogeochemical settings. One of the pockmark sites is characterized by evident methane (CH4) ebullition and high CH4 concentrations from ~2.4 to 8.9 mM within the sediments beneath. A large pockmark with a diameter of 110 m is located adjacent to the rock wall of a karst system and might thus be associated with groundwater discharge into the lake. Finally, spikes in electrical conductivity detected during a survey with a remotely operated vehicle (ROV) at a third pockmark site suggest a hydrogeological connection with the groundwater system in the underlying Triassic bedrock.

This third pockmark site we are studying more closely. We observed that the sediments inside the pockmark were clearly more liquified as compared to those at a reference site (outside the pockmark), providing further evidence for groundwater discharge that might presently be active. The porewater chemistry was similar at the two sites, except for the total dissolved Fe concentration which was about 2 to 5-fold lower inside the pockmark than at a reference site. Further chemical analysis of porewaters and the water column above the pockmark as well as a molecular investigation (e.g. 16S rRNA) of the sediments will be performed at two different seasons of the year (in fall and spring during the snowmelt season). All together, these results should help us to better assess the influence of groundwater discharge via this pockmark site on the hydrological balance and on the biogeochemistry of the lake, as well as to expand our limited knowledge on the mechanism of lacustrine pockmarks in general.
Rupture parameters of dynamic source models compatible with NGA-West2 GMPEs
Authors: Gallovic Frantisek , Valentova Lubica
Published: March 2020

Dynamic source inversions of individual earthquakes provide constraints on stress and frictional parameters, which are inherent to the studied event. However, general characteristics of both kinematic and dynamic rupture parameters are not well known, especially in terms of their variability. Here we constrain them by creating and analyzing a synthetic event database of dynamic rupture models that generate waveforms compatible with strong ground motions in a statistical sense.

We employ a framework that is similar to the Bayesian dynamic source inversion by Gallovič et al. (2019). Instead of waveforms of a single event, the data are represented by Ground Motion Prediction Equations (GMPEs), namely NGA-West2  (Boore et al., 2014). The Markov chain Monte Carlo technique produces samples of the dynamic source parameters with heterogeneous distribution on a fault. For all simulations, we assume a vertical 36x20km strike-slip fault, which limits our maximum magnitude to Mw<7. For dynamic rupture calculations, we employ upgraded finite-difference code FD3D_TSN (Premus et al., 2020) with linear slip-weakening friction law. Seismograms are calculated on a regular grid of phantom stations assuming a 1D velocity model using precalculated full wavefield Green's functions. The procedure results in a database with those dynamic rupture models that generate ground motions compatible with the GMPEs (acceleration response spectra in period band 0.5-5s) in terms of both median and variability.

The events exhibit various magnitudes and degrees of complexity (e.g. one or more asperities). We inspect seismologically determinable parameters, such as duration, moment rate spectrum, stress drop, size of the ruptured area, and energy budget, including their variabilities.  Comparison with empirically derived values and scaling relations suggests that the events are compatible with real earthquakes (Brune, 1970, Kanamori and Brodsky, 2004). Moreover, we investigate the stress and frictional parameters in terms of their scaling, power spectral densities, and possible correlations. The inferred statistical properties of the dynamic source parameters can be used for physics-based strong-motion modeling in seismic hazard assessment.
Event-driven Processing of Earth Observation Data
Authors: Rieke Matthes , Drost Sebastian , Jirka Simon , Vogt Arne
Published: March 2020

Earth Observation data has become available and obtainable in continuously increasing quality as well as spatial and temporal coverage. To deal with the massive amounts of data, the WaCoDiS project aims at developing an architecture that allows its automated processing. The project focuses on the development of innovative water management analytics services based on Earth Observation data such as provided by the Copernicus Sentinel missions. The goal is to improve hydrological models including but not limited to: a) identification of the catchment areas responsible for pollutant and sediment inputs; b) detection of turbidity sources in water bodies and rivers. The central contribution is a system architecture design following the Microservice architecture pattern: small components fulfil different tasks and responsibilities (e.g. managing processing jobs, data discovery, process scheduling and execution).  In addition, processing algorithms, that are encapsulated by Docker containers, can be easily integrated using the OGC Web Processing Service Interface. The orchestration of the different components builds a fully functional ecosystem that is ready for deployment on single machines as well as cloud infrastructures such as a Copernicus DIAS node or commercial cloud environments (e.g. Google Cloud Platform, Amazon Web Services). All components are encapsulated within Docker containers.

The different components are loosely coupled and react to messages and events which are published on a central message broker component. This allows the flexible scaling and deployment of the system. For example, the management components can run on physical different locations than the processing algorithms. Thus, the system supports the reduction of manual work (e.g. identification of relevant input data, execution of algorithms) and minimizes the required interaction of domain users. Once a Processing Job is registered within the system, the user can track the status of it (e.g. when it was last executed, if an error occurred) and will eventually be informed when new processing results are available.

In summary, this work targets to develop a system that allows the automated and event-driven creation of Earth Observation products. It is suitable to run on Copernicus DIAS nodes or on dedicated environments such as a Kubernetes Cluster.

In our contribution, we will present the event-driven processing workflows within the WaCoDiS system that enables the automation of water management related analytics services. In addition, we will focus on architectural details of the Microservice oriented system design and discuss different deployment options.
Definition of soil water content and rainfall thresholds for landslide occurrence
Authors: Piciullo Luca , Gilbert Graham
Published: March 2020

In the last decades, rainfall thresholds for landslide occurrences were thoroughly investigated, producing several different test cases and relevant technical and scientific advances. However, a recent literature review on rainfall thresholds articles (Segoni et al., 2018), published in journals indexed in SCOPUS or ISI Web of knowledge databases in the period 2008-2016, highlighted significant advances and critical issues about this topic. Only in the 11% of the analysed papers (a total of 115) there were installed instruments for measuring physical parameters other than rainfall. The implication was that, in most cases, the occurrence of landslides was forecasted considering exclusively a rainfall correlation, completely neglecting soil characteristics.

A reanalysis dataset (ERA5-Land) providing a consistent view of the evolution of land variables over several decades at an enhanced resolution has been used to evaluate the soil water content. Reanalysis combines numerical model data with observations from across the world into a globally complete and consistent dataset using the laws of physics. A comparison between in situ measurements with the results of the model has been carried out for two sites in Norway (Eidsvoll, Morsa catchmen) with 3 different vegetation types: grass, bush, tree. The results showed a good agreement between the modelled soil water content layer 2 and 3 (respectively representing 2 - 28 cm and 28 -100 cm depths) and, respectively, in-situ measurements at 30 and 50 cm depths.

Then, 15 Norwegian basins with moraine and peat covers and, previous landslide occurrences in the period 2009-2018, have been selected for correlations. Combinations of rainfall and soil water contents that triggered and not-triggered landslides have been analysed. Rainfall-soil water content thresholds have been defined for the selected basins highlighting the important role played by soil water content, together with rainfall, in triggering landslides. The use of the soil water content contributed to increase the performance of the thresholds and to reduce the uncertainties of landslide forecast.

This paper has been conceived in the context of the project "Klima 2050-Risk reduction through climate adaptation of buildings and infrastructure" http://www.klima2050.no/, and it is included into Work Package 3.3-Early warning systems.

 
Viscoelastic modeling results of the 79°N Glacier, Greenland
Authors: Christmann Julia , Rückamp Martin , Zeising Ole , Steinhage Daniel , Neckel Niklas , Helm Veit , Ralf Müller , Scheinert Mirko , Khan Shfaqat Abbas , Humbert Angelika
Published: March 2020

Grounding line/zone dynamics of floating-tongue glaciers is of major importance for changes in their contribution to sea-level rise. For floating-tongue glaciers, thermal forcing of oceanic heat and tidal forcing are the major processes acting in that zone. Here we deal with the response to tidal forcing. The 79°N Glacier, an outlet glacier of the North East Greenland Ice Stream, is the focus of the Greenland Ice Sheet Ocean Interaction project (GROCE) funded by the German Ministry of Education and Research. We present a study of this region considering the deformation of the glacier in response to ocean tidal forcing by means of observations and modeling. GPS measurements realized in 2017-2018 are analyzed for vertical and horizontal displacements of the glacier and its floating tongue. Observations on fully-grounded ice reveal a periodic horizontal displacement in response to ocean tidal forcing in a distance of more than 35 km upstream from the grounding line. In the hinge zone, i.e. the transition between grounded and floating ice, the tidal forcing leads to a measurable vertical bending of the ice and a periodic movement of the grounding line. Understanding the mechanisms of grounding line migration is important to better evaluate the contribution of grounded ice discharge to sea-level rise.

In order to model the measured displacements, a viscoelastic material model is required using the observed vertical displacements at the floating ice tongue as external forcing. Geometries obtained from AWI’s new ultrawideband radar form the basis for finite-element simulations in COMSOL. With the viscoelastic Maxwell material model, the response of the ice to ocean tidal forcing can successfully be modeled. Results obtained with a nonlinear Glen-type viscosity agree very well with the observed bending near the grounding line. The expected phase shift of the horizontal displacements upstream from the grounding line is well reproduced in the model.
Salinity and species richness determine mangrove canopy height
Authors: Perri Saverio , Detto Matteo , Molini Annalisa
Published: March 2020

Mangrove ecosystems play an important role in carbon sequestration of coastal wetlands through litterfall and soil carbon accumulation. Maximum canopy height (Hmax) is a key variable in assessing above-ground carbon stocks and productivity, and it is relatively easy obtained from forest inventories or satellite remote sensing products. However, the drivers that regulate canopy height in these ecosystems are still poorly understood. It is a common assumption that climatic drivers, such as precipitation and air temperature, account for most of the mangrove height variability. Nevertheless, local productivity and carbon allocation are known to be largely controlled by salinity, which represents one of the dominant sources of abiotic stress in tidal environments. Yet, the control of salinity on canopy height has received scarce attention in the literature.

In this study, we present a global analysis of Hmax as a function of seawater salinity, species richness, and air temperature. Our results identify both salinity and air temperature as major abiotic co-factors in control species richness and Hmax. For example, the largest number of species is observed in Southeast Asia (> 25), where high temperature co-occurs with low salinity. In contrast, low temperatures in subtropical zones and high salinity in arid regions strongly limit diversity. Such low diversity is generally associated with mangrove ecosystems with short canopy. The multivariate analysis of both global and regional patterns reveals that salinity is the main limiting factor for Hmax, while the air temperature is mostly unrelated to Hmax. The effects of salt-stress are particularly evident in ecosystems with low species richness (number of species ≤10), while it does not have a detectable effect on Hmax in species‐rich communities (number of species >10).

We hypothesize that high stress induced by salinity reduces the niche breadth and decreases competition for above-ground resources, limiting diversity and Hmax. On the other hand, more tolerable salinity conditions might promote species coexistence, competition for light, therefore increasing canopy height and mangrove productivity through complementary resource utilizations.
Moving from Latin America to Germany: Culture shock and challenges faced by a geoscientist family
Authors: Perez Liseth , Bücker Matthias
Published: March 2020

Geoscientists are often highly mobile, making them attractive candidates for academic positions. Nevertheless, changing your country of residency can be very challenging, and such challenges are amplified if one has small children, and especially if both parents are active researchers. We are both geoscientists, with specialties in paleolimnology and geophysics, and have a 2-year-old son and 7-year-old daughter. We are originally from Guatemala and Germany, and our children were born in Mexico, where we worked for seven years before moving to Germany.

Culture shock is often expected to be severe when moving from Europe to a developing country, like Mexico or Guatemala. In our case, however, we experienced serious cultural shock when we moved from Latin America to Germany. It became apparent that conditions were harsh for couples that try to live equitably at home and at work, and attempt not to neglect either family life or science. We identified multiple challenges in our daily life, such as: (1) the well-known lack of sufficient childcare options in Germany, (2) cultural differences at work, such as family-“unfriendly” scheduling of important meetings, (3) a lack of flexibility with respect to financial support for families whose members participate in professional symposia or fieldwork, and  (4) policies of granting institutions that sometimes, unintentionally, preclude family-friendly work in academic research.

Our personal experiences may help to elucidate why the gender disparity in science is larger in wealthy, central European countries such as Germany (28.0% female researchers, UNESCO 2018) than in many Latin American countries, such as Mexico (33.0%) and Guatemala (53.2%). By identifying key issues, we hope to improve the situation for parent researchers - both female and male. Changes will be required of universities in Germany and elsewhere in Europe that intend to improve the quality of research and teaching at their institutions by attracting young, talented, international scientists. We acknowledge that every case is different, but encourage universities that are building strong programs through internationalization of the faculty to consider the needs of families of incoming foreign researchers, and actively support dual-career professional couples.
McFAN experiment: An integrated analysis of the multiphase chemistry experiment in Fogs and Aerosols in the North China Plain
Authors: Su Hang , Ma Nan , Sun Yele , Tao Jiangchuan , Fu Pingqing , Cheng Yafang
Published: March 2020

Fine-particle pollution associated with winter haze threatens the health of more than 400 million people in the North China Plain. The Multiphase chemistry experiment in Fogs and Aerosols in the North China Plain (McFAN) investigated the physical-chemical mechanisms leading to the haze formation with a focus on the contributions of multiphase processes in aerosol and fogs. We integrated multiple platform observations with regional and box models to identify the key oxidation process producing sulfate, nitrate and secondary organic aerosols, and their impact. A new environmental chamber was deployed to conduct kinetic experiments with real atmospheric compositions in comparison to literature kinetic data from laboratory studies. The experiments were carried out for multiple years since 2017 at the Gucheng site in the center of polluted areas and have performed experiments in the winter season. The location of the site minimizes fast transition between clean and polluted air masses (e.g., in Beijing), and helps to maintain a pollution regime representative for the North China Plain. The multi-year consecutive experiments documented the trend of PM2.5 pollution and corresponding change of aerosol physical and chemical properties, and allowed to investigate newly proposed mechanisms. The preliminary results show new proofs of the key role of aqueous phase reactions in regulating the aerosol compositions during haze events.

Reference:

Zheng et al., Exploring the severe winter haze in Beijing: the impact of synoptic weather, regional transport and heterogeneous reactions. Atmospheric Chemistry and Physics 15, 2969-2983 (2015).

Cheng et al., Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China. Science Advances 2,  (2016).

Li et al., Multifactor colorimetric analysis on pH-indicator papers: an optimized approach for direct determination of ambient aerosol pH. Atmos. Meas. Tech. Discuss. 2019, 1-19 (2019).

Kuang et al., Distinct diurnal variation of organic aerosol hygroscopicity and its relationship with oxygenated organic aerosol. Atmos. Chem. Phys. Discuss. 2019, 1-33 (2019).

 
Dynamic Hydrological Discharge and Lake Modelling for Coupled Climate Model Simulations of the Last Glacial Cycle
Authors: Riddick Thomas , Brovkin Victor , Hagemann Stefan , Mikolajewicz Uwe
Published: March 2020

The continually evolving large ice sheets present in the Northern Hemisphere during the last glacial cycle caused significant changes to river pathways both through directly blocking rivers and through glacial isostatic adjustment. Associated with these changing river pathways was the formation and evolution of large glacial lakes such as Lake Agassiz. Studies have shown this changing hydrology had a significant impact on the ocean circulation through changing the pattern of freshwater discharge into the oceans. A coupled Earth system model (ESM) simulation of the last glacial cycle thus requires a hydrological discharge and lake model that uses a set of river pathways and lakes that evolve with Earth's changing orography while being able to reproduce the known present-day river network given the present-day orography. Here, we present a method for dynamically modelling rivers and lakes by applying predefined corrections to an evolving fine-scale orography (accounting for the changing ice sheets and isostatic rebound) each time the river directions and lakes basins are recalculated. The corrected orography thus produced is then used to create a set of fine-scale river pathways and these are then upscaled to a coarser scale on which an existing present-day hydrological discharge model within the JSBACH land surface model simulates the river flow. The associated glacial lakes are delineated from the same corrected fine scale orography; lake inflow and outflow being linked to the river flow model.
A study of the impact of very large wind farms on regional weather using the WRF model in high resolution
Authors: Jacobsen Simon , Walløe Hansen Aksel
Published: March 2020

The Weather Research and Forecasting (WRF) model fitted with the Fitch et al. (2012) scheme for parameterization of the effect of wind energy extraction is used to study the effects of very large wind farms on regional weather. Two real data cases have been run in a high spatial resolution (grid size 500 m). Both cases are characterized by a convective westerly flow. The inner model domain covers the North Sea and Denmark. The largest windfarm consists of 200.000 wind turbines each with a capacity of 8MW. The model is run for up to 12 hours with and without the wind farm. The impact on the regional weather of these very large wind farms are studied and presented. Furthermore, the effect of horizontal spacing between wind turbines is investigated. Significant impact on the regional weather from the very large wind farms was found. Horizontal wind speed changes occur up to 3500m above the surface. The precipitation pattern is greatly affected by the very large wind farms due to the enhanced mixing in the boundary layer. Increased precipitation occurs at the front? within the wind farm, thus leaving the airmass relatively dry downstream when it reaches the Danish coast, resulting in a decrease in precipitation here compared to the control run. The formation of a small low level jet is found above the very large wind farm. Furthermore, wake effects from individual wind turbines decrease the total power production. The wind speed in the real data cases are well above the speed of maximum power production of the wind turbines. Yet most of the 200.000 wind turbines are producing only 1MW due the wake effects. A simulation run with a wind farm of 50.000 8MW wind turbines was also run. This windfarm covers the same area as the previous one, but horizontal distance between wind turbines are 1000m instead of 500m. This configuration was found to produce a similar amount of power as the 200.000 configuration. However, the atmospheric impact on regional weather is smaller but still large with 50.000 wind turbines.
Rainfall seasonality changes in northern India across the 4.2 ka event
Authors: Giesche Alena , Breitenbach Sebastian F.M. , Marwan Norbert , Hartland Adam , Plessen Birgit , Adkins Jess F. , Haug Gerald H. , French Amanda , Petrie Cameron A. , Hodell David A.
Published: March 2020

Despite intensive research efforts by archaeologists, geomorphologists, and palaeoclimatologists, the climatic and environmental changes accompanying the societal changes in the wider Indus/Thar region c. 4000 years ago remain puzzling. In particular, rainfall seasonality might be an important determinant for societal well-being. A major hurdle to a more detailed understanding of climate-human interaction is the relative scarcity of well-dated and highly resolved proxy records.

We present a multi-proxy record from aragonitic stalagmite DHAR-1 collected in Dharamjali Cave, Uttarakhand, India, that spans c. 1600 years between c. 4.25 and 2.6 ka BP.  The stalagmite has been dated with 13 U/Th dates with average uncertainties of <18 years (2σ). In addition to c. 1600 oxygen and carbon isotope samples, element ratios (X/Ca) were measured using high resolution μXRF and laser ablation ICPMS at 25 μm resolution.  

The DHAR-1 record represents the most precisely dated speleothem record to date from northern India, covering the mid-Holocene 4.2 ka BP event and the millennium thereafter. The attained sub-decadal to seasonal resolution allows robust assessment of both regional and local hydrological changes, and changes in amount and temporal distribution of summer and winter rainfall. 

The speleothem record reveals decadal-scale trends that can be related to changes in seasonality. The δ18O record reveals a 220-year period of weakened ISM from 4.2 to 3.98 ka BP. A contemporaneous increase in δ13C, and decrease in U/Ca, Ba/Ca, and Sr/Ca point to increased prior aragonite precipitation (PAP) resulting from increased aridity above the cave extending throughout the dry season. The ISM intensified after c. 3.7 ka BP while dry seasons remained dry, with a resultant increase in seasonality. Lower PAP after c. 3.4 ka BP can be interpreted as sign of reduced rainfall seasonality.

We compare the results with available records from the wider region, and discuss potential implications of the suggested changes in seasonality for agriculture-based societies.
The role of transform faults during back-arc spreading centre jumps
Authors: Schliffke Nicholas , van Hunen Jeroen , Gueydan Frederic , Magni Valentina , Allen Mark B.
Published: March 2020

Jumps in the location of back-arc spreading centres are a common feature of back-arc basins, but the controlling factors are not understood. In several narrow subduction zones with a long subduction history, such as the Scotia arc or Tyrhennian Sea, several spreading centres have been active in the course of history with regular, quasi-instantaneous jumps towards the retreating trench. A prominent feature of these regions are large bounding transform (‘STEP’) faults. However, whether STEP faults influence the (unknown) dynamics spreading centre jumps remains to be explored.

 

We therefore run 3D-models to simulate a long narrow subducting slab, bound by continents, which retreats and creates necessary STEP-faults self-consistently. The results offer a new mechanism for back-arc spreading jumps: After the creation of a back-arc spreading centre in the retreating subduction system, transform faults between trench and back-arc basin form. Spreading jumps are thus a consequence of the fact that these constantly elongating transform faults, which decouple the overriding plate from neighbouring plates, fail to remain active once a threshold length (~1.3x plate width) is reached. Subsequently, the back-arc basin and neighbouring plates are strongly coupled, and ongoing trench retreat localizes stresses and rapidly ruptures the overriding plate closer to the trench while the old spreading centre is abandoned.  In a parameter study, the results further explain why the narrowest subduction zones, such as the Calabrian Arc, experience more frequent and closer spreading jumps than the long-period jumps of a wider subduction zone such as the Scotia Arc. The widest subduction zones should not undergo any back-arc spreading jumps with this mechanism, consistent with other natural examples.
Intra-seasonal Oscillation of Abyssal Currents in the Middle East Pacific Ocean
Authors: Kuang Fangfang , Zhang Junpeng , Pan Aijun , Zhu Dayong
Published: March 2020

In this work, the intra-seasonal oscillation of the abyssal currents in the Middle East Pacific Ocean is investigated using direct observations from ADCP instruments, which are mounted on a subsurface mooring deployed at 154oW，10oN. The observation shows that the intra-seasonal (20-100 days) oscillation part of the kinetic energy accounts for more than 40% of the low-frequency flow kinetic energy between 200~2000m, while accounts for more than 50% under 2000m; the intra-seasonal oscillation of meridional flow is more obvious than that of zonal flow. The meridional velocity in the upper layer (100-1000m) shows an oscillation at periods of 50~90 days, which is most obvious at the depth of 500m; from 200m to the bottom layer currents shows an synchronous oscillation at a period of 30 days lasting for several months, and the oscillation signal is the strongest in the deep layer (4600m); The correlation is good between the 20~40 day band passed meridional current at the bottom layer and that of the geostrophic current. The observed temperature of 4000m and 5000m also shows similar characteristics of 30 days period oscillation, which has good correlation to the sea level height. The reanalysis data shows the 30 days oscillation of the abyssal currents is propagated from west to east at a speed of about 0.29m/s while the 40~100 day oscillation is propagated at a speed of about 0.1m/s; the intensity of the intra-seasonal oscillation has obvious interannual variations, which may be related to the change of the eddy energy of the sea surface.
Impacts of stratospheric dynamical variability on total inorganic fluorine from observations and models constrained by state-of-the-art reanalyses
Authors: Prignon Maxime , Bernath Peter F. , Chabrillat Simon , Chipperfield Martyn P. , Dhomse Sandip S. , Feng Wuhu , Minganti Daniele , Servais Christian , Smale Dan , Mahieu Emmanuel
Published: March 2020

Man-made halogenated compounds emitted from the Earth’s surface ultimately reach the stratosphere where they undergo photolysis, leading to three main fluorine reservoirs: hydrogen fluoride (HF), carbonyl fluoride (COF2) and carbonyl chloride fluoride (COClF). This process is directly influenced by the strength of the mean meridional circulation of the stratosphere, the Brewer-Dobson Circulation (BDC). The BDC is projected to speed-up with the greenhouse gases induced global warming. However, studies have highlighted a multiyear variability in the strength of the BDC resulting in hemispheric asymmetries in observed and modelled trends of age of air and long-lived tracers.

Total inorganic fluorine (Fy, the fluorine weighted sum of HF, COF2 and COClF) is used here as a tracer of the stratospheric circulation changes. We perform an analysis and interpretation of Fourier transform infrared (FTIR) multidecadal time-series of HF and COF2 from the Jungfraujoch (Switzerland, 46.55°N) and Lauder (New-Zealand, 45.03°S) stations and from the space-borne Atmospheric Chemistry Experiment - Fourier Transform Spectrometer (ACE-FTS). Indeed, the summation of HF and COF2 is a very good proxy of Fy as we determine, from ACE-FTS and the chemical-transport model (CTM) TOMCAT, that COClF is only accounting for less than 5% of the total Fy budget.

The kinematic CTM BASCOE (Belgian assimilation system for chemical observations) is used here to assess the representation of the investigated circulation changes in four state-of-the-art meteorological reanalyses, i.e., ERA-Interim, JRA-55, MERRA and MERRA-2. We also investigate if WACCM4 (Whole Atmosphere Community Climate Model version 4) is able to reproduce these changes through a free-running simulation.

The ground-based and satellite FTIR time-series of COF2 show contrasting results over their common time period (2004-2019), with a positive total column trend above the Jungfraujoch, and a non-significant (ground-based) or decreasing trend (ACE-FTS) above Lauder. We find large discrepancies between the BASCOE-CTM simulations, with MERRA-2 inducing overly large simulated Fy total columns which could confirm the weaker tropical upwelling highlighted in previous age of air studies.
Why water bodies of Iran have been dried up?
Authors: Moshir Panahi Davood , Aminjafari Saeid , Zahabiyon Bagher
Published: March 2020

The status of natural water bodies in terms of water quality and quantity can be considered a criterion for the environmental status of their upstream catchment. The presence of natural water bodies with good condition can be a sign proper of water resource management activities in the upstream catchment for sustainable development. Iran has been undergoing a rapid development process in recent decades. Nowadays, in most water bodies in Iran, the water level has been decreased and even disappeared in some cases. Lake Urmia is a well-known example of drying lakes in Iran. This study aims at identifying the main effective drivers in drying up of the main lakes in Iran.

Iran is a country with an approximate area of 1,648,000 km2 that has an arid and semi-arid climate with an average precipitation of 311 mm/year. The most important water bodies in Iran are Lake Urmia and Maharloo, Hoor-al-Azim and Gavkhuni Wetlands, and Gorgan Bay. This study focuses on the mentioned waterbodies and upstream catchment information.

At first, climate conditions and changes such as drought and changes in their properties are studied to find the answer to this question. Then, non-climatic factors and their changes such as urban/rural population changes, industrial growth, agricultural changes such as land area, crop yield, and the type of irrigation were studied. To achieve this purpose, the time series of the surface level of these five waterbodies was measured using satellite images. Then the time of significant changes in the time series of the surface level of each waterbody was determined using the Pettit test. As a result, the time interval for each waterbody was divided into a two-time span, before and after the change point. This created a time interval for climatic and non-climatic comparisons to identify effective factors.

The climatic data from the synoptic stations located in and around each waterbody catchment have been used to study the climatic conditions, and the sum of precipitation and mean temperature have been evaluated as the main climate parameters along with the SPIE drought index and characteristic changes. In order to evaluate effective non-climatic factors, changes in urban/rural population factors, agricultural land level, the number of agricultural products, and industrial units were used based on official statistics.

The results of this study indicate that the year of significant changes in the time series of lakes was between 1996 and 2001. Crop yield change growth was the main factor in the upstream catchment of all lakes as a result of changes in the irrigation patterns.
Publishing computational research – A review of infrastructures for reproducible and transparent scholarly communication
Authors: Konkol Markus , Nüst Daniel , Goulier Laura
Published: March 2020

Many research papers include results based on data that is analyzed using a computational analysis implemented, e.g., in R. Publishing these materials is perceived as being good scientific practice and essential for the scientific progress. For these reasons, organizations that provide funding increasingly demand applicants to outline data and software management plans as part of their research proposals. Furthermore, the author guidelines for paper submissions more often include a section on data availability, and some reviewers reject submissions that do not contain the underlying materials without good reason [1]. This trend towards open and reproducible research puts some pressure on authors to make the source code and data used to produce the computational results in their scientific papers accessible. Despite these developments, publishing reproducible manuscripts is difficult and time-consuming. Moreover, simply providing access to code scripts and data files does not guarantee computational reproducibility [2]. Fortunately, several projects work on applications to assist authors in publishing executable analyses alongside papers considering the requirements of the aforementioned stakeholders. The chief contribution of this poster is a review of software solutions designed to solve the problem of publishing executable computational research results [3]. We compare the applications with respect to aspects that are relevant for the involved stakeholders, e.g., provided features and deployment options, and also critically discuss trends and limitations. This comparison can be used as a decision support by publishers who want to comply with reproducibility principles, editors and program committees who would like to add reproducibility requirements to the author guidelines, applicants of research proposals in the process of creating data and software management plans, and authors looking for ways to distribute their work in a verifiable and reusable manner. We also include properties related to preservation relevant for librarians dealing with long-term accessibility of research materials.

 

References:

1) Stark, P. B. (2018). Before reproducibility must come preproducibility. Nature, 557(7706), 613-614.

2) Konkol, M., Kray, C., & Pfeiffer, M. (2019). Computational reproducibility in geoscientific papers: Insights from a series of studies with geoscientists and a reproduction study. International Journal of Geographical Information Science, 33(2), 408-429.

3) Konkol, M., Nüst, D., & Goulier, L. (2020). Publishing computational research - A review of infrastructures for reproducible and transparent scholarly communication. arXiv preprint arXiv:2001.00484.
Applications of an UAV aerogeophysical integrated survey system(iUAGS) in china
Authors: Lu Ning , Xi yongzai , Zheng hongshan , Liu junjie , Wu shan
Published: March 2020

iUAGS is an emerging UAV aerogeophysical integrated survey system ( magnetic & radiation) based on the rainbow series UAV(the CH-3),which has many advantages such as long-endurance,low altitude, all-day time work ability, high precision,low cost,etc.It’s leading researched and developed by Institute of Geophysical and Geochemical Exploration (IGGE) of China Geological Survey (CGS).Since 2013,more than 150,000 kilometers’ pretty good and high quality geophysical data have been acquired using iUAGS in Duobaoshan of Heilongjiang province , Karamay and Kashi area of Xinjiang province,YanCheng of Jiangsu province in china.And a new survey hosted by IGGE is now working for earth deep probe project in southern china.With the development of UAV and aerogeophysical technology，We believe that iUAGS will be widely and better used in more fields.  
Using Gamma-Ray and X-Ray Computed Tomography for Porosity Quantification of Reservoir Analogue Rocks
Authors: Nova Abraão , Ribeiro Frederico , Oliveira Pamalla , Amancio Daniel , Machado Cássia , Carolina Alexandra , Paixão Marcio , Antonino Antonio , Barbosa Enivaldo , Barbosa Antônio , Lourenço Maria , Rodrigues Marcos , Heck Richard
Published: March 2020

During the last few decades, X-ray micro-computed tomography (µCT) has been largely used to characterize rock properties and to create high-resolution 3D digital image volumes. It has allowed access to important information about porous systems in reservoir rocks. However, the reliable quantification of porosity of rocks which present porous volumes ranging from centimeter to nanometer scale remains a challenge. Assessment of nano scale porous volume is very difficult by image segmentation techniques, due to the intrinsic limits of the x-ray imaging method. Moreover, image processing for analysis of various types of porosity in the same sample, including microporosity could be computationally expensive. We present a method based in the Gamma-Ray computed tomography (axis attenuation) that can substantially improve the limits presented by conventional X-ray microtomography. This study compared the porosity values acquired by typical segmentation methods for microtomography images, and by the values obtained trough the proposed method of gamma-ray computed tomography to calculate the porosity. Results of both approaches were compared to porosity measurements obtained through experimental equipment (helium porosimeter). These analyses were performed in core samples of limestones and sandstones analogous of Brazilian oil reservoirs. The Gamma Ray Attenuation method (axis attenuation) presented a better correlation (R² = 0.9588) to the experimental measurements when compared to the image segmentation methods (R² = 0.9194). The results suggest that Industrial application of gamma ray tomography for precise evaluation of large number of core samples can be highly effective. Furthermore, the gamma ray data can be integrated with data provided by conventional µCT image processing to complement information regarding morphological aspects.

Keywords: Porous System, X-ray microtomography, Gamma Ray tomography,  Reservoir rocks