bluuebunny/crossref_metadata_2025 huggingface dataset:
Teleseismic P-wave travel time tomography of the Alpine upper mantle using AlpArray seismic network data
Authors: Paffrath Marcel , Friederich Wolfgang ,   AlpArray Working Group
Published: March 2020

We perform a teleseismic P-wave travel time tomography to examine geometry and slab structure of the upper mantle beneath the Alpine orogen. Vertical component data of the extraordinary dense seismic network AlpArray are used which were recorded at over 600 temporary and permanent broadband stations deployed by 24 different European institutions in the greater Alpine region, reaching from the Massif Central to the Pannonian Basin and from the Po plain to the river Main. Mantle phases of 347 teleseismic events between 2015 and 2019 of magnitude 5.5 and higher are evaluated automatically for direct and core diffracted P arrivals using a combination of higher-order statistics picking algorithms and signal cross correlation. The resulting database contains over 170.000 highly accurate absolute P picks that were manually revised for each event. The travel time residuals exhibit very consistent and reproducible spatial patterns, already pointing at high velocity slabs in the mantle.

For predicting P-wave travel times, we consider a large computational box encompassing the Alpine region up to a depth of 600 km within which we allow 3D-variations of P-wave velocity. Outside this box we assume a spherically symmetric earth and apply the Tau-P method to calculate travel times and ray paths. These are injected at the boundaries of the regional box and continued using the fast marching method. We invert differences between observed and predicted travel times for P-wave velocities inside the box. Velocity is discretized on a regular grid with an average spacing of about 25 km. The misfit reduction reaches values of up to 75% depending on damping and smoothing parameters.

The resulting model shows several steeply dipping high velocity anomalies following the Alpine arc. The most prominent structure stretches from the western Alps into the Apennines mountain range reaching depths of over 500 km. Two further anomalies extending down to a depth of 300 km are located below the central and eastern Alps, separated by a clear gap below the western part of the Tauern window. Further to the east the model indicates a possible high-velocity connection between the eastern Alps and the Dinarides. Regarding the lateral position of the central and eastern Alpine slabs, our results confirm previous studies. However, there are differences regarding depth extent, dip angles and dip directions. Both structures dip very steeply with a tendency towards northward dipping. We perform various general, as well as purpose-built resolution tests, to verify the capabilities of our setup to resolve slab gaps as well as different possible slab dipping directions.
Storylines of the 2018 Northern Hemisphere heat wave at pre-industrial and higher global warming levels
Authors: Wehrli Kathrin , Hauser Mathias , Seneviratne Sonia I.
Published: March 2020

The 2018 summer was unusually hot in large areas of the Northern Hemisphere and simultaneous heat waves on three continents led to major impacts to agriculture and society. The event was driven by the anomalous atmospheric circulation pattern during that summer and it was only possible in a climate with global warming. There are indications that in a future, warmer climate similar events might occur regularly, affecting major ‘breadbasket’ regions of the Northern Hemisphere.

This study aims to understand the role of climate change for driving the intensity of the 2018 summer and to explore the sensitivity to changing warming levels. Model simulations are performed using the Community Earth System Model to investigate storylines for the extreme 2018 summer given the observed atmospheric large-scale circulation but different levels of background global warming: no human imprint, the 2018 conditions, and different mean global warming levels (1.5°C, 2°C, 3°C, and 4°C). The storylines explore the consequences of the event in an alternative warmer or colder world and thus help to increase our understanding of the drivers involved. The results reveal a strong contribution by the present-day level of global warming and provide an outlook to similar events in a possible future climate.
Neural interpretation of European summer climate ensemble predictions
Authors: Carvalho Oliveira Julianna , Zorita Eduardo , Baehr Johanna , Ludwig Thomas
Published: March 2020

Current state-of-the-art dynamical seasonal prediction systems still show limited skill, particularly over Europe in summer. To circumvent this, we propose a neural network-based classification of individual ensemble members at the initialisation of summer climate predictions, prior to performing a skill analysis. Different from European winter climate, largely dominated by the North Atlantic Oscillation, predictability of European summer climate has been associated with several physical mechanisms, including teleconnections with the tropics. Recent studies have shown that predictive skill improves when the dominant physical processes in a given season are identified at the initialisation of a prediction. Each of these dominant physical processes is associated with large-scale circulation patterns, often depicted by modes of Empirical Orthogonal Functions (EOF). We argue that Self-Organising Maps (SOM), a type of neural network classifier, can provide further insight on interpreting the predictive skill of mixed resolution hindcast ensemble simulations generated by MPI-ESM. This is achieved by identifying which circulation patterns over the North Atlantic-European sector (NAE) at the initialisation of hindcasts lead to more predictable states than others, their preferable transition states, and whether the spatial structure of each SOM mode play a role in shaping climate over Europe. We train SOM networks on sea level pressure fields of ERA-20C reanalysis at the initialisation of the seasonal prediction system (every May) for the period of 1900-2010, covering NAE. We compare the SOM-derived modes with circulation patterns derived from EOF analysis, and characterise each class of circulation regime. This analysis is used to distinguish classes of predictions with two different sets of MPI-ESM initialised simulations with 10 and 30 members, covering the period of 1902-2008 and 1982-2016, respectively. We then discuss the differences and advantages of performing a neural interpretation of the skill of an ensemble prediction, over traditional skill analysis.
K-Ar dating of recent thrusts: an application to the Tertiary clay gouges in the Northern Apennines of Italy
Authors: Carboni Filippo , VIola Giulio , Aldega Luca , van der Lelij Roelant , Brozzetti Francesco , Barchi Massimiliano R.
Published: March 2020

The Northern Apennines (NA) are a characteristic example of foreland fold-and-thrust belt (FTB) migrating towards its foreland. The progressive and quite regular eastward migration of the NA has been classically constrained in time by relying on the age of the syn-orogenic foreland basins, mainly determined by means of foraminifera and nannofossil biostratigraphy.

The well-known age of deformation makes the NA a perfect area where to test the reliability of the K-Ar illite dating applied to Cenozoic deformation involving siliciclatic deposits. In particular, we present the results of the first attempt to directly date, by K-Ar on illite separated from fault rocks, Neogene thrusts within the Trasimeno Tectonic Wedge (TTW), an imbricate thrust complex mainly made up of Tertiary siliciclastic rocks, located in the inner-central part of the NA, which represents the external front of the so-called Tuscan Nappe.

We sampled two WSW-dipping thrust faults, whose fault cores are composed of scaly gouge formed at the expense of the pelitic component of the host rocks. X-ray diffraction (XRD) and K-Ar isotopic analysis of multiple grain-sizes (from < 0.1 to 10 µm) allowed us to discriminate between syn-kinematic illite crystals formed during thrusting and detrital illite crystals inherited from the host rock. XRD data show a mineralogical association composed of quartz, calcite, albite, K-feldspar, chlorite, kaolinite and two populations of illite polytypes (1Md and 2M1). After the X-ray semiquantitative analysis, the results of the K-Ar dating of the two samples were regressed by the Illite Age Analysis (IAA) approach to assessing the effects of potential host rock contamination. Fault slip along the thrusts is then constrained to 15.2 ± 7.6 Ma and 15.4 ± 16.6 Ma.

Despite the large errors, the obtained dates are in excellent agreement with the timing of deformation along the base of the TTW, bracketed between the late Aquitanian and the latest Burdigalian – earliest Langhian and, more in general, with the proposed time evolution of the Northern Apennines.

Even if based on a limited dataset, our results suggest that the application of K-Ar dating of fault gouge can be extended to tectonic settings where independent constraints are not available and thus it becomes a valuable tool to study and constrain the time-space evolution of FTBs in recent and even active orogens.
Ionosphere research with a nanosatellite’s radio wave spectrometer
Authors: Kallio Esa , Harri Ari-Matti , Aikio Anita , Alho Arno , Fontell Mathias , Jarvinen Riku , Kauristie Kirsti , Kero Antti , Kestilä Antti , Koskimaa Petri , Lukkari Juha-Matti , Knuuttila Olli , Loyala Jauaries , Niittyniemi Joonas , Norberg Johannes , Rynö Jouni , Turunen Esa , Vanhamäki Heikki
Published: March 2020

The Suomi100 nanosatellite was launched on Dec. 3, 2018 (http://www.suomi100satelliitti.fi/eng). The 1 Unit (10 cm x 10 cm x 10 cm) polar orbit cubesat will perform geospace, ionosphere and arctic region research with a white light camera and a radio wave spectrometer instrument which operates in the 1-10 MHz frequency range.

Suomi 100 satellite type of nanosatellite, so called CubeSat, provides a cost effective possibility to provide in-situ measurements in the ionosphere. Especially, combined CubeSat observations with ground-based observations give a new view on auroras and associated electromagnetic phenomena. Especially joint CubeSat – ground based observation campaigns enable the possibility of studying the 3D structure of the ionosphere.

Increasing computation capacity has made it possible to perform simulations where properties of the ionosphere, such as propagation of the electromagnetic waves in the medium frequency, MF (0.3-3 MHz) and high frequency, HF (3-30 MHz), ranges is based on a 3D ionosphere model and on first-principles modelling. Electromagnetic waves at those frequencies are strongly affected by ionospheric electrons and, consequently, those frequencies can be used for studying the plasma. On the other hand, even if the ionosphere originally enables long-range telecommunication at MF and HF frequencies, the frequent occurrence of spatio-temporal variations in the ionosphere disturbs communication channels, especially at high latitudes. Therefore, study of the MF and HF waves in the ionosphere has both a strong science and technology interests.

We present computational simulation and measuring principles and techniques to investigate the arctic ionosphere by a polar orbiting CubeSat which radio instrument measures HF and MF waves. We introduce 3D simulations, which have been developed to study the propagation of the radio waves, both ground generated man-made radio waves and space formed space weather related waves, through the 3D arctic ionosphere with a 3D ray tracing simulation. We also introduce the Suomi100 CubeSat mission and its observations.
Evaluation of riparian forest water supply with groundwater monitoring and numerical modelling
Authors: Gribovszki Zoltán , Cseke Csaba , Csáki Péter , Horváth László , Kalicz Péter , Nagy László , Szőke Előd , Zagyvai-Kiss Katalin Anita
Published: March 2020

Riparian zone forests are a special type of agro-forestry systems. As buffer zones protect stream systems against stress factors. These ecosystems are diverse so ecologically valuable, on the other hand, they are valuable (because of high productivity) from an economic viewpoint as well.

Riparian forests are very vulnerable because they strongly depend on surplus water (shallow groundwater or seasonally flooded condition). Long drought periods caused by changing climate induce lowering of the water table and shortening flooded periods. With reasonably designed water supply systems, these negative processes can be stopped, and valuable ecosystems can be preserved.

The effect of an artificial structures (new lakes and bottom thresholds) induced water supply was evaluated in Kaszó Forest (Somogy county, Hungary). Eco-Hydrological monitoring (groundwater and phenological) was conducted on 14 regular (under the effect of water supply interventions) and 4 control plots in different forest ecosystems. The impact of water supply interventions was interpreted with spatio-temporal groundwater level difference analysis and found that surplus water had a positive effect on the riparian zone water table (40-50 cm rise in the neighbourhood of new lakes) and vegetation.

A complex field monitoring (hydro-meteorological and phenological measurements) was conducted on three representative locations. 1-D Hydrus model was successfully calibrated for an alder and two common oak forest plots. Diurnal signal of groundwater levels was used for ET estimation in the model. Model results showed that groundwater uptake of forest vegetation was significantly increased (30%) regarding water supply interventions.

Acknowledgements: The research was supported by EFOP-3.6.2-16-2017-00018 in University of Sopron project.

Keywords: riparian forest, water supply, groundwater monitoring, 1-D Hydrus model
European Research Council (ERC) success rates of men and women in the geosciences
Authors: Alves de Jesus Rydin Claudia , Farina Busto Luis , Mugabushaka Alexis-Michel
Published: March 2020

The European Research Council (ERC), Europe’s premiere funding agency for frontier research, views equality of opportunities as an essential priority. The ERC monitors closely various demographic data yearly on every call and has taken actions to tackle imbalances and potential implicit and explicit biases.

The ERC poster is focused on demographic geosciences data for the three main funding schemes: Starting Grant, Consolidator Grant and Advanced Grant. The data of the ERC population is expressed statistically, with focus on gender and geographic location.

Success rates of geosciences applicants by gender are compared to the both success rates from other fields of science at the ERC and other funding organisations in Europe.

Recent initiatives at the ERC to tackle imbalances are also presented.
Impacts of infrastructure and climate changes on reindeer herding in the Yamal, west Siberia.
Authors: Kumpula Timo , Laptander Roza , Forbes Bruce C.
Published: March 2020

The traditional landuse in the Yamal is reindeer herding practiced by nomadic Nenets herders. The hydrocarbon industry is presently the source of most ecological changes in the Yamal peninsula and socio-economic impacts experienced by migratory Nenets herders who move annually between winter pastures at treeline and the coastal summer pastures by the Kara Sea.

In central Yamal peninsula which is permafrost area both natural and anthropogenic changes have occurred during the past 40 years. Mega size Bovanenkovo Gas Field was discovered in 1972 and it was opened in production and in 2012. We have studied gas field development and natural changes like increases in shrub growth, cryogenic landslides, drying lakes in the region and these impacts to Nenets reindeer herding.

Nenets managing collective and privately owned herds of reindeer have proven adapt in responding to a broad range of intensifying industrial impacts at the same time as they have been dealing with symptoms of a warming climate and thawing permafrost phenomena.

The results of climate change together with the industrial development of the Yamal Peninsula have a serious impact to the Nenets nomadic reindeer husbandry. Their consequences make Nenets reindeer herders to change their migration routes and the way of working with reindeer. During several years, we were making interviews with Nenets reindeer herders about the influence of climate change and industrialization of the tundra on the quality of Nenets nomads’ life and their work with reindeer. Reindeer herders said that impacts of industrial development have reduced their migration opportunities, as well as the quality of pastures for grazing, which has fatal the effects during icing on the tundra in the winter. At the same time, in the summer reindeer have more food because increasing of the green vegetation. 

Here we detail both the climate change impacts and spatial extent of gas field growth, landslides drying lakes, shrub increase and the dynamic relationship between Nenets nomads and their rapidly evolving social-ecological system.
Continuous source system and distributed acoustic sensing for reservoir to crust monitoring
Authors: Tsuji Takeshi , Ikeda Tatsunori , Yamaoka Koshun
Published: March 2020

We have developed a permanent seismic monitoring system using a continuous seismic source and distributed acoustic sensing (DAS). The active seismic source system continuously generates waveforms with wide frequency range. By stacking the continuous waveforms, our monitoring system improves signal-to-noise ratio of the seismic signal. Thus, less-energy vibration using small-size source could be utilized for the exploration of deeper geological targets. Presently, we have deployed the small-size monitoring source system in the Kuju geothermal field in the northeast Kyushu Island, Japan. Although our monitoring source system is small and generates high frequency vibrations (10-20Hz), the signal propagated >80 km distance using two-month continuous source data. Our field experiments demonstrate that variation of seismic velocity of the crust could be identified with high accuracy (~0.01 %). To record the monitoring signal from continuous source system, we need to deploy seismometers. Deployment of many seismometers increase spatial resolution of the monitoring results. Recently, we have deployed the DAS system close to the continuous seismic source system. Using DAS, dense and long seismometer network can be realized, and we succeeded to identify the temporal variation of seismic velocity. By using both continuous source and DAS, we are able to monitor wide area with lower cost. Our monitoring system could accurately monitor the larger-scale crust and smaller-scale reservoir in high temporal resolution.
Derivation of the full current density vector in the Earth's ionosphere low- and mid-latitude F region using ESA's Swarm satellites
Authors: Fillion Martin , Hulot Gauthier , Alken Patrick , Chulliat Arnaud , Vigneron Pierre
Published: March 2020

A new multi-spacecraft method to recover estimates of the average three-dimensional current density in the Earth's ionosphere is presented. It is demonstrated using the ESA's Swarm satellite constellation and by taking advantage of the favorable geometrical configurations during the early phase of the mission. The current density vector is calculated inside prisms whose vortices are defined by the satellite positions. The mathematical formalism differs from previous approaches such as the one known as the ”curlometer”. It makes use of the well-known curl-B technique and involves an inverse problem which allows for error propagation through the calculation. Data from the vector field magnetometers of the three satellites are used and special care is taken to characterize the errors on these data. The method is applied in the low- and mid-latitude F-region on 15 February 2014. It provides latitudinal profiles of the full current density vector together with the associated error bars in the morning and evening sectors. We observe several dynamical features such as clear signatures of field-aligned interhemispheric currents, potential signatures of the wind dynamo current system as well as mid-latitude east-west currents.
Exhumed fjords of Namibia: A glimpse of the Late Paleozoic Ice Age in the Karoo Supergroup of the Kaokoland basin
Authors: Dietrich Pierre , Griffis Neil , Kettler Christoph , Le Heron Daniel , Montañez Isabel
Published: March 2020

The Late Paleozoic Ice Age (LPIA) is the longest-lived and most extreme glacial period (from ca 360 to 260 Ma) of the Phanerozoic. Over this time span, ice masses are thought to have covered most of Gondwana, from South America to Australia. In southern Africa, the sedimentary, stratigraphic and geomorphic evidence of this glaciation is recorded in the Karoo Supergroup. The Kaokoland region of northern Namibia is characterized by a dense network of deep (200-700 m), large (5-15 km) and U-shaped incised valleys formed during the LPIA (Martin, 1981). A recent reappraisal of the morphology and sedimentary infill of these outstanding geomorphic features attests of their glacial origin. Valley flanks are spectacularly striated and scratched while valley floors are characterized by extensive whalebacks and roches moutonnées. Moreover, the sedimentary infill at the base of these valleys is mainly composed of coarse deposits (conglomerates, diamictites, erratics, striated clasts) interpreted as glaciogenic in origin. Of particular interest, however, is the presence of coarse (ranging from sand to boulders) glaciogenic sediments plastered on the sub-vertical and striated valley sides. Vitally, the elevation of these deposits in the valleys appears to correspond to a linear bench-like level, which may reflect a marginal moraine allowing for the maximum thickness of the LPIA glaciers to be derived, an unprecedented advance. For the first time in the characterization of a pre-Pleistocene glacial epoch, an ice thickness has been inferred. Collectively, these features prove that the valleys were carved and occupied by ice masses during the LPIA from which ice volume, and in turn their contribution to global eustasy, can directly be inferred. In addition, postglacial sedimentary succession abutting on valley flanks and showcasing marine, deltaic and estuarine affinities clearly indicate that these glacial valleys formed fjords in the immediate aftermath of the LPIA, after the retreat of the ice margins. Sealed by the Karoo Supergroup sediments through Carboniferous to early Cretaceous times, these major glaciogenic morphologic features have subsequently been exhumed during the Cenozoic. Thus, some desertic landscapes of northern Namibia correspond to a glacial relief inherited from the LPIA at ca ~ 300 Myr ago.

 

Martin, H., 1981, The Late Paleozoic Dwyka Group of the South Kalahari Basin in Namibia and Botswana and the subglacial valleys of the Kaokoveld in Namibia, in Hambrey, M.J., and Harland, W.B. (eds.) Earth’s Pre-Pleistocene Glacial Record: New York, Cambridge University Press, 61–66
Risk perception and social vulnerability of population in coastal areas subject to climate change in two Mediterranean regions
Authors: Antronico Loredana , Coscarelli Roberto , D'Amico Sebastiano , De Pascale Francesco , Di Matteo Dante , Micallef Anton
Published: March 2020

Coastal areas are particularly sensitive to climate change. Owing to a significant increase in human activities and pressures, these areas have become particularly susceptible to extreme physical phenomena that increase the exposure and vulnerability of population. The Authorities ought to make strong efforts to: i) take the necessary measures and actions to reduce the negative impacts of the natural phenomena on the coastal areas, which are also due to the climate change; ii) investigate the factors that influence the communities’ perception of natural hazards and the climate change. Indeed, in order to effectively manage the negative impacts of climate change both considerable scientific know-how and of people’s perception of the risk associated to them is paramount.

Within this framework, a Research Project funded under the Agreement on Scientific Cooperation between CNR and the University of Malta (UoM) was developed. The Project is organized in order to synergistically combine the various scientific researches of the two partners (CNR-IRPI and University of Malta) in the context of natural hazards, public knowledge and perception of geo-hydrological risk and climate change. Calabria (Southern Italy) and Malta, the two Mediterranean regions considered as target areas for the Project, show different geomorphological and climatic settings but, although with different exposure levels, they are both affected by extreme physical phenomena and climate change.

The goals of the Project are the following: i) identify the population’s awareness, perception and preparation concerning the effects that climate change has on coastal areas through online and face to face questionnaires; ii) assess the social vulnerability and develop a specific Index of Social Vulnerability in relation to natural hazards in the target areas (Calabria and Malta); iii) propose useful tools to local authorities and to responsible of territory planning and of risk prevision, prevention and management; iv) raise awareness among stakeholders and citizens around the issues linked to the effects of climate change on the increased frequency of extreme natural events. In the first half of the Project, a survey based on questionnaire for analysing population’s perception of geo-hydrological risks and climate change was carried out and the obtained results were analysed. At the end of the Project, the results will help to perform a wider and more thorough risk analysis that takes into account the potential increase in exposure and vulnerability of coastal areas population as a result of climate change in the two Mediterranean regions.
The STIMTEC experiment at the Reiche Zeche ULab
Authors: Boese Carolin , Renner joerg , Dresen Georg ,   STIMTEC Team
Published: March 2020

Between early 2018 and late 2019 the STIMTEC hydraulic stimulation experiment was performed at ca.~130 m below surface at the Reiche Zeche research mine in Freiberg, Saxony/Germany. The project aims at gaining insight into the creation and growth of fractures in anisotropic and heterogeneous crystalline rock units, to develop and optimise hydraulic stimulation techniques and to control the associated induced seismicity under in situ conditions at the mine-scale. These aspects of failure and associated seismicity are important for the development of enhanced geothermal energy systems. We present the infrastructure developed for the STIMTEC experiment and provide an overview of the obtained data, including 295 m of core material retrieved from 17 boreholes, 225 m of acoustic TV log, >50 TB of continuous passive seismic data from four field stimulation and hydraulic testing campaigns, as well as ~300 active velocity calibration measurements.

We highlight some of the first results regarding the hydro-mechanical and seismic response to the stimulation, the rock mass characterisation in-situ and in the laboratory, as well as 3-D numerical modelling of the stress state and fracturing. The heterogeneity and anisotropy of the strongly foliated metamorphic gneiss significantly affects fracture creation and propagation in the experiment.
Climate change impacts on crop water productivity in Africa using a multi-model inter-comparison
Authors: Weerasinghe Imeshi , Chawanda Celray James , van Griensven Ann
Published: March 2020

Evapotranspiration (ET) or the water vapour flux is an important component in the water cycle and is widely studied due to its implications in disciplines ranging from hydrology to agricultural and climate sciences. In the recent past, growing attention has been given to estimating ET fluxes at regional and global scales. However, estimation of ET at large scales has been a difficult task due to direct measurement of ET being possible only at point locations, for example using flux towers. For the African continent, only a limited number of flux tower data are openly available for use, which makes verification of regional and global ET products very difficult. Recent advances in satellite based products provide promising data to fill these observational gaps.

In this study we propose to investigate the Climate Change (CC) impact on crop water productivity across Africa using ET and crop yield predictions of different crop models for future climate scenarios. Different model outputs are evaluated including models from both the ISI-MIP 2a and 2b protocols. Considering the problem of direct observations of ET being difficult to obtain, especially over Africa, we use ET estimates from several remotely sensed derived products as a references to evaluate the crop models (maize) in terms of magnitude, spatial patterns and variations between models. The crop model results for crop yield are compared to FAO reported crop yields at country scale. The results show a very strong disagreement between the different crop models of the baseline scenario and when compared with ET and crop yield data.  Also, a very large uncertainty is obtained for the climate change predictions. It is hence recommended to improve the crop models for application in Africa.
Macropore-matrix mass transfer: reactive solute transport as quantified with Fluorescence imaging
Authors: Haas Christoph , Ellerbrock Ruth , Gerke Horst H.
Published: March 2020

Preferential flow paths in soils play a major role for transport processes of heat, gas, water, and solutes and are important adsorption sites. For mass-exchange processes and water storage in soils, small-scaled soil properties, like the spatial distribution of adsorption sites and their accessibility, and the permeability are crucial. Interfaces between macropores (i.e., earthworm burrows, cracks, and root channels) and the soil matrix control the mass exchange. Water and solute transfer through the interface between bio-pores, aggregate or crack surfaces and the matrix was traced at the scale of small soil blocks (≤45 mm edge length) with Fluorescein (i.e., a reactive, fluorescent dye). The objectives were to visualize and quantify hydraulic transport, and sorption characteristics of earthworm-, root- and shrinkage-induced interfaces. Batch experiments were performed to calibrate the Na-Fluorescein tracer concentration versus fluorescence-intensity relationship and to derive parameters for two kinetic sorption models (i.e., Freundlich vs. Langmuir). Fluorescence imaging in the laboratory of small soil blocks was applied with a self-constructed spraying device, and with the help of the calibration, small-scaled dye-concentration maps were derived. Time- and interface-dependent positions of the wetting fronts in vertical direction were estimated with the help of the cumulative infiltration. Assuming equilibrated conditions between Na-Fluorescein in solution (calculated by multiplying the locale dye-concentration and the local water content) and Na-Fluorescein sorbed to soil, the total mass transfers as a function of macropore-type and spraying time were determined. The results of the mass transfer for water and reactive solutes were characteristic for the soil structure type and depending on the composition of the macropore-matrix interface. Differences were explained by alterations in soil structure and chemical composition of the coatings. Results suggest relations between mass exchange and observable soil properties. This can be helpful for improving the numerical simulation of macropore-matrix mass transfer and inverse simulations of small-scaled hydraulic, transport, and sorption characteristics of macropore walls.
inDust: International Network to encourage the use of monitoring and forecasting DUST products
Authors: Basart Sara , Nickovic Slodoban ,   inDust Core Group
Published: March 2020

Sand and Dust Storms (SDS) are extreme meteorological phenomena that generate significant amounts of airborne mineral dust particles. SDS plays a significant role in different aspects of weather, climate and atmospheric chemistry. Also, SDS represents a severe hazard for life, health, property, environment and economy, which is aligned with several Sustainable Developed Goal (SDG) targets established by the United Nations (UN). Understanding, managing, and mitigating SDS risks and effects requires fundamental and cross-disciplinary knowledge.

Over the last few years, there is an increasing need for SDS accurate information and predictions to support early warning systems, and preparedness and mitigation plans in addition to growing interest from diverse stakeholders, such as solar energy plant managers, health professionals, aviation and policymakers from environmental and health public sectors. Current attempts to transfer tailored products to end-users are not coordinated, and the same technological and social obstacles are tackled individually by all different groups, a process that makes the use of data slow and expensive.

The EU-funded COST Action inDust (www.cost-indust.eu, CA16202) has an overall objective to establish a network involving research institutions, service providers and potential end-users of information on airborne dust that can assist the diverse socio-economic sectors affected by the presence of high concentrations of atmospheric dust. In line with this main objective, the network is being worked on the identification and engagement of representatives of dust affected socio-economic sectors (targeting on air quality and health, aviation and solar energy) from different countries in Europe but also in North Africa and the Middle East. Moreover, the participation of South African, American and importantly Asian partners brings the possibility of extending the application of the developed products, protocols and tools well beyond the European borders, including areas like Asian regions where dust particles play a significant role in the air quality and meteorological processes.

The primary outcomes of the network are the identification of the needs of the various and new dust-related products and services able to satisfy these needs. As a result, the network has been working on a dust catalogue which includes an overview of (ground-based and satellite) observations and model products.
Representativeness of decadal-scale climate signals in ice-core aerosol records
Authors: Erhardt Tobias , Jensen Camilla , Hörhold Maria , Fischer Hubertus
Published: March 2020

Records of past aerosol deposition to the polar ice sheets have enabled us to study variability in different parts of the earth system in great temporal detail over past glacial cycles. Furthermore, the high temporal resolution of ice-core aerosol records has been the basis for precise dating of climate records using annual layer counting. Nonetheless, the intermittent character of show deposition and especially the redistribution of snow on the surface of the ice sheet intrinsically affects the preservation of climate signals in the ice. This strongly limits how representative a climate record from a single ice core can be. It has been well established that even though seasonal variability might be preserved in an ice-core aerosol record, the inter annual variability of that record is different from a different core from the same site.

Until now most of the investigations have focused on inter annual representatives. This is mostly due to limited sample availability as multiple long records are needed for investigations on longer time scales. However, with the prospect of new high-resolution records over the Holocene from the EastGRIP ice core, understanding the representativeness of this record on decadal time scales is an important question. To tackle this problem, we use high-resolution aerosol records from multiple closely spaced ice cores from the EastGRIP deep ice core drill site. The records approximately cover the last millennium and are sub-seasonally resolved enabling the study of interannual to decadal variability over multiple aerosol species. All records are dated using annual layer counting and cross dating to the EastGRIP deep ice core using volcanic match points. In the presented pilot study, we focus on records of sea-salt and dust related aerosol species as well as on episodic aerosol signals from volcanos and wildfires.
The impact of hurricanes on the island of Saint-Martin (French West Indies) from 1954 to 2017: how are our society changes?
Authors: Pasquon Kelly , Jouannic Gwenaël , Gargani Julien , Tran Duc Minh Chloé , Crozier Denis
Published: March 2020

Natural disasters lead to many victims and major damage in France and around the world. In 2017, Hurricane Irma hit the French islands of Saint-Martin and Saint-Barthélemy (West Indies), killing 11 people and causing more than €2 billion in insured damage. Ranked 5 in category on the Saffir-Simpson scale, with average winds of 287 km/h, this hurricane highlighted the vulnerability of our society to this type of phenomenon.

One can question the inability of society to face up to and recover from the consequences of these events. In this sense, this work questions the adaptation of the island of Saint-Martin to hurricanes and its entire environment. We have chosen to focus on the evolution of this island over 65 years: from 1954 to 2017 (before Hurricane Irma). We mainly used aerial images of IGN (Institut National de l’Information Géographique et Forestière) available regularly since 1947. Among the elements that have served us to characterize this evolution, we have focused on land use (buildings, infrastructure and anthropization) and demographics.

We show, in this study, that between 1954 and 2017 (before Hurricane Irma), Saint Martin had to adapt to numerous constraints, some of which were far more important than hurricanes. In 65 years, the population density of the French part of Saint Martin increased from 75 to 668 inhab/km². The majority of this increase occurred in a five year period following the Pons law of 1986 which favoured tax breaks for real estate investment. More than 12 000 buildings have been built in Saint Martin to welcome the new inhabitants of the island as well as tourists. Many neighbourhoods experienced significant growth which started in the late 80's. However we observe differences in urban planning, a result of social and territorial segregation which exists on the island. On the one hand, there are private residences in affluent neighbourhoods, on the other hand working-class neighbourhoods with vulnerable dwellings. The effect of hurricanes on this society, which has been highly unequal since the 1960's up to the 1980's, is to reinforce inequalities. The fragile habitats of the poorest populations have been more deeply affected than the richest parts of the population which have been financially supported for reconstruction.
Climatological Analysis of the Potential of Solar and Wind Energy in Germany
Authors: Drücke Jaqueline , Borsche Michael , James Paul , Kaspar Frank , Pfeifroth Uwe , Ahrens Bodo , Trentmann Jörg
Published: March 2020

Renewable energies, like solar and wind energy, play an important role in current and future energy supply in Germany and Europe. The renewable energy production highly depends on weather, which leads to an increasing impact of the meteorological fluctuations on energy production.

Here, climatological datasets with high spatial and temporal resolution are used to simulate the electrical energy production from photovoltaic (PV) installations and wind turbines. For the solar radiation the CM SAF SARAH 2.1 dataset is used, which includes global and direct radiation with a temporal resolution of 30 minutes and a grid spacing of 0.05°. The data is available from 1983 to 2017. The regional reanalysis COSMO-REA6 provides hourly wind speed data from 1995 to 2015 with a spatial resolution of 6km. Based on these datasets capacity factors are calculated for PV and wind energy for Germany. Using the spatial distribution of solar panels and wind turbines as well as electrical power generation data from 2015 the simulated capacity factors were converted into (potential) hourly power generation in Germany from 1995 to 2015. 

The main aim of this study is to identify weather regimes where renewable energy production from solar and wind was comparable low. Due to high power production from solar radiation, which exhibits a comparable low variability and high predictability, in summer, all low production events occur in winter. During winter, wind power is the main contributor to renewable energy production. On the basis of the hourly time series of simulated power production the weather regimes that are associated with multiple days of low renewable energy production are identified and analysed. European regions are identified that exhibit comparably high potential renewable power production for those weather regimes with low energy production in Germany.  
Stable isotope-based approach to validate effects of stand structure and understory on soil water in a Japanese forest plantation
Authors: Omomo Saki , Onda Yuichi , Mohamed Boutefnouchet , Chiu Chenwei , Gomi Takashi , Hudson Sean , Zhang Yupan , Hudson Janice
Published: March 2020

 Many researchers have studied the effects of plantation thinning on forest environments, including plantation thinning-induced changes in soil water, which recharges ground water. However, most of these studies have sampled only either preferential flow or matrix flow. To properly understand soil water movement, soil water must be classified into matrix flow and preferential flow, and we must sample and analyze them separately. Therefore, our purpose is to reveal the differences in the water stable isotope rates in soil water on different vegetation distributions to consider the change of soil water.

 We used suction lysimeters adding 60kPa and zero-tension lysimeters to collect two types soil water separately. We used modular zero-tension plate lysimeters which improve the problems in conventional zero-tension plate lysimeter of both low water collection efficiency by unsaturated soil on the plate and soil disturbance by inserting the plate.

 Matrix flow tended to be isotopically heavier under open canopy than under closed canopy, and isotopically heavier in areas with no understory vegetation than in areas with understory vegetation. Preferential flow tended to be almost the same water stable isotope rate as throughfall. We could see this trend better in heavy rain events than in light rain events, and the trend suggests mixing with matrix flow in the light rain. There was little difference between water stable isotope rates of throughfall in different vegetation distributions.

 The implications of these results suggest that soil water which recharges ground water is isotopically heavy in a degraded plantation, and becomes isotopically heavier with the increase in forest floor evaporation after plantation thinning, but becomes isotopically lighter as understory vegetation grows.
Explanation for the increase in high altitude water on Mars observed by NOMAD during the 2018 global dust storm
Authors: Neary Lori , Daerden Frank , Aoki Shohei , Whiteway James , Clancy Robert Todd , Smith Michael , Viscardy Sébastien , Erwin Justin , Thomas Ian , Vandaele Ann Carine ,   Members of the NOMAD Team
Published: March 2020

Using the GEM-Mars three-dimensional general circulation model (GCM), we examine the mechanism responsible for the enhancement of water vapour in the upper atmosphere as measured by the Nadir and Occultation for MArs Discovery (NOMAD) instrument onboard ExoMars Trace Gas Orbiter (TGO) during the 2018 global dust storm on Mars.

Experiments with different prescribed vertical profiles of dust show that when more dust is present higher in the atmosphere, the temperature increases and the amount of water ascending over the tropics is not limited by saturation until reaching heights of 70-100 km. The warmer temperatures allow more water to ascend to the mesosphere. The simulation of enhanced high-altitude water abundances is very sensitive to the vertical distribution of the dust prescribed in the model.

The GEM-Mars model includes gas-phase photochemistry, and these simulations show how the increased water vapour over the 40-100 km altitude range results in the production of high-altitude atomic hydrogen which can be linked to atmospheric escape.
Sensitivity of Greenland ice sheet projections to spatial resolution in higher-order simulations: the AWI contribution to ISMIP6-Greenland using ISSM
Authors: Rückamp Martin , Goelzer Heiko , Kleiner Thomas , Humbert Angelika
Published: March 2020

Projections of the contribution of the Greenland ice sheet to future sea-level rise include uncertainties primarily due to the imposed climate forcing and the initial state of the ice sheet model. Several state-of-the-art ice flow models are currently being employed on various grid resolutions to estimate future mass changes in the framework of the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6). Here we investigate the sensitivity to grid resolution on centennial sea-level contributions from the Greenland ice sheet and study the mechanism at play. To this end, we employ the finite-element higher-order ice flow model ISSM and conduct experiments with four different horizontal resolutions, namely 4, 2, 1 and 0.75 km. We run the simulation based on the ISMIP6 core GCM MIROC5 under the high emission scenario RCP8.5 and consider both atmospheric and oceanic forcing in full and separate scenarios. Under the full scenarios, finer simulations unveil up to 5% more sea-level rise compared to the coarser resolution. The sensitivity depends on the magnitude of outlet glacier retreat, which is implemented as a series of retreat masks following the ISMIP6 protocol. Without imposed retreat under atmosphere-only forcing, the resolution dependency exhibits an opposite behaviour with about 5% more sea-level contribution in the coarser resolution. The sea-level contribution indicates a converging behaviour ≤ 1 km horizontal resolution. A driving mechanism for differences is the ability to resolve the bed topography, which highly controls ice discharge to the ocean. Additionally, thinning and acceleration emerge to propagate further inland in high resolution for many glaciers. A major response mechanism is sliding (despite no climate-induced hydrological feedback is invoked), with an enhanced feedback on the effective normal pressure N at higher resolution leading to a larger increase in sliding speeds under scenarios with outlet glacier retreat.