bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding runoff formation in a basin with Peat Bog and Podzol hillslopes
Authors: Vlček Lukáš , Šípek Václav , Kofroňová Jitka , Kocum Jan , Doležal Tomáš , Janský Bohumír
Published: March 2020

This research deals with the hydrological function of Peat Bog in a catchment where Peat Bog (formed by Histosol or other hydromorphic soils) covers a part of the area (40-60%). In this study, two soil types, creating two main hillslopes of the experimental catchment, form the dominant soil types (Podzol and Histosol) in the Šumava Mountains, Czechia. A modified HBV model was used for the estimation of the contribution of each soil type to common outflow and for the estimation of the water balance. According to previous research and field observations, dominant hydrological processes were described for each hillslope (soil). The model confirmed previous results concerning dominant preferential flows at Peat Bog hillslope and Podzol hillslope; moreover, it quantified a ratio between fast and slow flow in soils. At Peat Bog hillslope, the majority of outflow (67%) was formed from the upper soil layer (Acrotelm). In the mineral soil hillslope, a larger portion of runoff was generated from the lower soil layers or bedrock interface (61%). Peat Bog contributes to a stream mainly during rainfall events; however, the model showed also significant deep percolation at the Peat Bog hillslope and considerable contribution to baseflow during a year. Generally, more precipitation water was turned into runoff at the Peat Bog hillslope by the model, which was indicated by a lower rate of actual evapotranspiration (21% of precipitation), compared to 29% in the case of Podzol hillslope. If we consider land use changes in this locality in terms of expanding or reducing peat areas (draining, drains damming, droughts, etc.), this model could sufficiently estimate hydrological behaviour of local streams and thus, can be potentially used in hydrological planning by local authorities.
Identification of nitrate sources, hot spots, and dilution in the Danube River Basin using a multitracer approach
Authors: Halder Janine , Vystavna Yuliya , Douence Cedric , Resch Christian , Gruber Roman , Heiling Maria , Wassenaar Len Irwin
Published: March 2020

The Danube is Europe`s second longest river, stretching from Germany to the Black Sea. Water quality in the Danube River Basin is regularly monitored by the national authorities of all riparian countries and in addition for specific water quality data during the Joint Danube Surveys (JSD), which is organised by the International Commission for the Protection of the Danube River every 6 years.

This study presents the results of water stable isotopes and stable isotopes (15N and 18O) of nitrate as well as major ion analysis from 3 JDS (2001, 2007, 2019). Results indicate that water stable isotopes allow to trace differences in the amount of snowmelt contribution to the Danube and hence the dilution effects of pollutants e.g. nitrate. The oxygen and nitrogen isotope compositions of nitrate are clearly indicating that nitrate in the Danube main stream mainly derives from waste water effluents, which input is increasing along the stream. This can furthermore be confirmed by results of micropollutant studies that demonstrate an increase of widely consumed pharmaceuticals (carbamazepine, diclofenac and caffeine) at different sections of the Danube River affected by tributary inflows and discharge from urban settlements.

In summary, this study is an example of combining isotope techniques, hydrological methods but also emerging compounds in order to approach the fate of anthropogenically derived nitrate within the Danube Basin. The results of this study aim to support the 2021 update of the Danube River Basin Management Plan as well as water monitoring practices across the Danube countries.
Role of dimethyl sulfide on the formation and growth of aerosols, and its impact on liquid clouds in the Arctic summer
Authors: Ghahreman Roya , Gong Wanmin , Norman Ann-Lise , Beagley Stephen R. , Akingunola Ayodeji , Makar Paul A.
Published: March 2020

Atmospheric dimethyl sulfide, DMS, is the main biogenic source of sulfate particles in the Arctic atmosphere. Sulfate particles have a net cooling effect, which can partially offset Arctic warming from absorbing aerosols, such as black carbon. As efficient cloud condensation nuclei (CCN), sulfate particles are also able to influence the cloud’s microphysical properties. 

DMS production and emission to the atmosphere increase during the Arctic summer, due to a greater ice-free sea surface area and higher biological activity. In the model simulation of a field campaign conducted over the Canadian high Arctic during the summer of 2014 (NETCARE; Abbatt et al. 2019), the inclusion of DMS in the model, GEM-MACH, resulted in a significant increase, up to 100%, in the modelled atmospheric SO2 in some regions of the Canadian Arctic. Analysis of the modelled size-segregated aerosol sulfate indicated that DMS has the most significant impact on particles in the size range of 50 – 200 nm in this case. Simulations have shown that localized regions of high seawater DMS can have a significant impact on atmospheric concentrations.

Further investigation of DMS impact on the Arctic summer cloud microphysics was carried out by using a fully coupled version of GEM-MACH. Overall, the model simulations show that the inclusion of DMS in model leads to an increase in cloud droplet number concentrations (CDNC) and a decrease in droplet mean mass diameters (MMD), and has no significant effects on liquid water content (LWC). The impact of DMS on Canadian weather forecasts will be evaluated using operational forecast tools.
Seismic noise analysis of broadband stations of the Italian Seismic Network by Power Spectral Density
Authors: Catania Maria , D'Alessandro Antonino , Greco Luca , Martorana Raffaele , Scudero Salvatore
Published: March 2020

The Italian Seismic Network (IV) consists of more than 500 stations located throughout the Italian territory.

The detection capability of  network is constrained by its location performance that is affected by the seismic noise levels variations depending on the characteristics of the dominant source. Discriminating the noise level in each stations may allow to improve in its performance, in order to reduce noisy stations to detect even the smaller energetic seismic events sometimes hidden by high noise values. The main goal of this research has been to establish the characteristics (frequency content) and origin of seismic noise background at these sites and secondly to assess the effects of performance of the network.

For this purpose we have estimated the Power Spectral Density (PSD) of seismic noise selecting only a subset of 233 stations equiped with broadband velocimeters (with minimum period of 40 seconds and with a high sensitivity until to 120s) and operating at least three consecutive years of available data (2015-2017).

The variations of seismic background noise have been investigated using also the relative Probability Density Funcionts (PDF). The data processing of signals carried out with the robust method proposed by McNamara and Buland, (2004). In this study, the analysis was limited in the frequency band from 0.025 to 30 Hz, in accordance with the seismic sensors bandwidth. Four different frequency bands have been identified: 0.025-0.12, 0.12-1.2, 1.2-10 and 10-30 Hz. Each of these has been associated to a main type of source, in agreement with the literature.

A preliminary data analysis has been carried out to understand the statistical properties of the noise power, in the four class identified, both in space and frequency domains. Extracting  the PDFs  all stations, it was produced a representative seismic noise model that it could be considered as a new reference noise for Italian territory. Histograms have been computed for each band, both for vertical and horizontal components and its ratio. In addition, a spatial-statistical analysis was performed showing a good correlation of noise level with some weather conditions and anthropogenic source. Several clustering techniques were applied to the data to identified group of stations with similar PSD level, attributable to the same noise source. Furthermore, a correlation between the noise found at the different stations and spatial data (maps of rainfall, winds, coastlines, ect…) was carried out for a better characterization of the type of source.
Differences and similarities between the 2018 and 2003 droughts for the Rhine basin studied in terms of evaporative sources
Authors: Benedict Imme , van Heerwaarden Chiel , van der Linden Eveline , Weerts Albrecht , Hazeleger Wilco
Published: March 2020

Droughts can be studied from an atmospheric perspective by analysing the large-scale circulation resulting in a lack of water, or from a hydrological perspective by understanding the interaction of precipitation, evaporation, soil moisture and temperature at the land surface. Here, both perspectives are captured as we study the evaporative sources resulting in precipitation over the Rhine basin. These evaporative sources, being continental or oceanic, can give an indication of the vulnerability of a basin to ongoing and future land-use changes. We focus on the anomalous evaporative sources of the Rhine basin during the dry summers of 2018 and 2003, to understand what the contribution is of local recycling of precipitation versus advection of moisture into the basin to the total amount of precipitation over the Rhine basin. We do so by using ERA5 re-analysis data from 1979 to 2018 and the Eulerian moisture tracking model WAM-2layers.

During an average summer, the evaporative sources of the Rhine basin are mostly located over the Atlantic ocean. In addition there is a substantial contribution of continental evaporation, mostly from land regions west of the Rhine basin. During the summer of 2018 a persistent high pressure system (blocking) prevented moisture input from the Atlantic ocean and therefore relative more recycling of moisture over land took place (both continental areas outside the basin and within the Rhine basin). Due to the anti-cyclonic movement around the high pressure area, we also found a larger contribution of evaporative sources from continental regions east of the Rhine basin.

The amount of local recycling can be expressed in the precipitation recycling ratio, the local generated precipitation divided by the total precipitation in a region. We found higher than average recycling ratios during the dry summer months of 2018. Thus, due to the blocking more local evaporation resulted in precipitation over the Rhine basin, indicating the increased dependence on local land-surface processes. In general, we found a clear correlation between higher than normal recycling ratios and lower than normal precipitation in summer. An exception is the end of the dry summer of 2003, when low recycling ratios are found, probably indicating drying out of the soils and therefore lower evaporation rates.

To conclude, although the summer of 2003 and 2018 were both very dry, their characteristics in terms of moisture sources and thereby their dependence on the land surface were found to be rather different. In 2018, local recycling was important, contrasting to 2003 when the drying out of the soils made local recycling less important. These differences between two dry years over the same region highlight the important role of the land surface in precipitation feedbacks.
Retrieving paleopoles using newly mapped lunar magnetic anomalies within basins
Authors: Oliveira Joana S. , Hood Lon L.
Published: March 2020

Orbital spacecraft magnetic field observations show that several isolated magnetic anomalies are found to be heterogeneously distributed over the lunar surface. The magnetic anomalies origin is still debated; however, it is largely accepted that an ambient core magnetic field was present during their formation. Contrary to previous studies, here we focus only on anomalies that are related to basins/craters, which correspond to the best possibility to hold ancient core field information. In particular, the basin rocks become thermoremanently magnetized as the melt sheet cools down slowly recording the ambient magnetic field that was present when the crater was formed.

We build regional magnetic field maps using data from quiet orbits of Lunar Prospector and Kaguya spacecraft. When comparing these regional maps to existing global models, several differences and details are discovered. Further investigation is required to understand why small scales are missing from global models. For each mapped crater, we perform inversions for the magnetization direction to estimate the corresponding paleopole position (defined as the north magnetic pole when the anomaly formed). In detail, a grid of dipoles is placed over the basin inner depression, where the melt sheet is believed to be. All dipoles have the same common direction, nonetheless different dipole moments.

Preliminary results show that paleopole positions of regionally mapped anomalies associated with craters are not in absolute agreement with previous paleopole studies. Also of significance is the distribution of dipoles obtained, which seem to be consistent with inferred impactor trajectories. We conclude that paleopole position results are highly dependent on the technique and choices we make to construct the magnetic field maps. Further studies of several other craters will be performed, but we expect large differences when using regionally mapped anomalies. Our results will help to better constrain the lunar ancient core field morphology.
Towards improved disaster preparedness and climate proofing in semi-arid regions: development of an operational seasonal forecasting system
Authors: Lorenz Christof , Portele Tanja , Laux Patrick , Kunstmann Harald
Published: March 2020

Seasonal hydrometeorological forecasts have the potential to significantly improve the regional water management, particularly in water-scarce regions. This includes a better disaster preparedness by developing e.g. forecast-based action plans for extreme climatic events like droughts and anomalous wet conditions. However, raw global products from data providers like the European Centre for Medium Range Weather Forecasts (ECMWF) cannot be directly used for regional applications due to model biases and drifts as well as a coarse spatial resolutions of 35km and more. In this study, we present a comprehensive dataset of operationally available seasonal hydrometeorological forecasts based on ECMWF’s newest seasonal forecast system SEAS5 that is a) corrected for biases against ECMWF ERA5 reanalysis data and b) spatially disaggregated to a higher spatial resolution of 0.1° (approx. 10km). We adopt a modified version of the Bias-Correction and Spatial Disaggregation (BCSD) technique, which is a highly robust method for regionalizing e.g. global climate data. The final repository contains daily ensemble forecasts for precipitation, temperature and radiation from 1981 to the present for 7 different semi-arid river basins in Iran (Karun), Sudan and Ethiopia (Tekeze-Atbara and Blue Nile), West-Africa (Niger and Volta), Brazil (Rio São Francisco) and Ecuador (Catamayo-Chira). In total, forecasts for more than 2.5 Million days for each variable and study region are corrected and disaggregated. An evaluation against reference data from ERA5 shows significantly reduced biases for the monthly averages as well as consistent and lead-independent forecast characteristics like wet/dry-day frequencies. As the entire repository is freely available, it provides an optimal test-bed for evaluating the forecast skill in different study regions; it allows to develop and implement e.g. hydrological forecasting systems and to train and educate local stakeholders and water experts. Our operational output of the forecasting system is already used by several authorities and weather services in Iran and Sudan; it thereby constitutes a large step towards an improved disaster preparedness and, hence, the climate proofing of the water sector particularly in these semi-arid regions.
Digitising archive large-format analogue aerial photography with alternative methods; Implications for photogrammetric processing
Authors: Ford Andrew , Papworth Heather
Published: March 2020

Most large-format analogue aerial photography, especially in the form of roll negatives, is now held in centralised archives, but much still exists elsewhere, notably in the form of positive prints. Whilst many large archiving bodies have been and continue to digitise their holdings of such aerial photography using professional photogrammetric scanners, they are often prohibitive (on the grounds of cost and/or logistics) for use with low-volume, dispersed collections. Therefore, alternative methods are sought, which are presented here. Such alternatives can be subject to relatively poor geometric accuracy, making photogrammetric processing problematic. Here the results of photogrammetric processing with prints digitised using alternative methods are compared and contrasted with digitised roll negatives of the same frames. The quality of resulting elevation data are assessed against reference elevations, using a test site with topography which has remained stable over decades.
Surface runoff evolution on moraines in silicate and carbonate proglacial areas of the Swiss Alps
Authors: Maier Fabian , van Meerveld Ilja
Published: March 2020

In many areas of the world, the surface of the earth is changing rapidly. Surface runoff is one of the processes that can dramatically modify the shape of our landscapes but is also affected by the land surface characteristics. However, our understanding of the evolution of overland flow characteristics and the feedback mechanisms between hydrological, pedological, biological and geormorphological processes that affect surface runoff is limited.

We used a space-for-time approach and studied 3 plots (4m x 6m each) on four different aged moraines (several decades to ~13.500 years) on the Sustenpass near the Steinglacier and in the karstic glacier foreland of the Griessfirn near Klausenpass (total of 24 plots) to determine how surface runoff generation changes during landscape evolution. We used artificial rainfall experiments with three different intensities to determine the surface flow ratio, peak flow rate, timing and duration of surface runoff. The addition of tracers (2H and salt) to the sprinkling water and sampling of soil water allowed identification of the mixing of the water within the slopes and the interaction of overland flow pathways with the subsurface. In addition, the runoff samples and sensor-based turbidity measurements provide an estimate of the erosion rates during extreme events. In order to link the differences in surface runoff generation with the pedological and biological characteristics of the slopes, soil and vegetation samples were taken on each plot to determine soil texture and root characteristics and the saturated hydraulic conductivity was measured in situ at three different depths.

The results show that the surface runoff amount and related erosion rates, response times and mixing of surface runoff and soil water change during landscape development and can largely be explained by related changes in soil surface and near surface characteristics. However, the rate of these changes during landscape evolution depends on the geology.
Wave-current Interactions in the Aghulas current: Impact on ship behavior
Authors: Le Goff Clément , Mironov Alexey , Chapron Bertrand
Published: March 2020

Ocean waves Interacting with large scale ocean currents is a frequent cause of sea-state variability [Ardhuin et al 2017, Quilfen et al 2018, Quilfen and Chapron 2019]. Such situations can lead to sea-state hazards, crucial for shipping security. The Great Agulhas current system is an area of very intensive maritime traffic, where dangerous localized sea-state amplification by the current has quite regularly been reported. 

In absence of wind and wave-induced motions, the heading and drift of every ship along its trajectory can be estimated from the near-surface oceanic current map. This first guess can then be compared with real ship parameters obtained from satellite-collected ship Automatic Identification System (AIS) messages. During Southwestern storm-swell wave conditions, with wind and waves aligned against the current, some ships experience pronounced navigation difficulties, slowing down up to 2 m/s,  and frequently maneuvering to keep their heading perpendicular to dominant waves. Superposed multiple individual ship trajectories can then help map anomalous areas, and to relate them to localized strong wave-current effects such as large refraction of waves by the oceanic current.

[Ardhuin et al 2017] : Ardhuin, F., S. T. Gille, D. Menemenlis,C. B. Rocha, N. Rascle, B. Chapron, J. Gula, and J. Molemaker (2017), Small-scale open ocean
currents have large effects on wind wave heights, J. Geophys. Res. Oceans, 122, 4500–4517, doi:10.1002/2016JC012413.

[Quilfen et al 2018] :Quilfen Yves, Yurovskaya M., Chapron Bertrand, Ardhuin Fabrice (2018). Storm waves focusing and steepening in the Agulhas current: Satellite observations and modeling. Remote Sensing Of Environment, 216, 561-571. Publisher's official version :

[Quilfen and Chapron, 2019] : Quilfen, Y., & Chapron, B. (2019). Ocean surface wave-current signatures from satellite altimeter measurements.
Geophysical Research Letters, 46.

 
Use of multiple tracers and groundwater flow modelling for the estimation of groundwater travel times to water supply wells, vulnerability assessments and improved management of well fields
Authors: Hinsby Klaus , Purtschert Roland , Musy Stéphanie , Sültenfuss Jürgen , Wachs David , Aeschbach-Hertig Werner , Kidmose Jakob , Troldborg Lars , Gulbrandsen Mats
Published: March 2020

Groundwater dating and travel time distributions are important tools and data for assessment of the vulnerability of water supply wells towards pollution from the surface. Here we present selected results from more than 30 water supply and monitoring wells from major Danish water companies. The wells were recently sampled and investigated using multiple environmental tracers including 85Kr, 39Ar, 3H/3He, 14C, SF6, CFCs and noble gases and different groundwater modeling techniques. The results demonstrate the value of groundwater dating and travel time estimations for the assessment of the history and fate of contaminants in the subsurface. This information is crucial for the assessment of the efficiency of measures to mitigate pollution of groundwater by harmful substances such as pesticides, nitrate and a large range of emerging contaminants. We demonstrate how groundwater ages and travel time distributions can be used to assess the vulnerability or susceptibility of water supply wells towards pollution, and how level specific sampling in long well screens can provide additional important information for assessment of the vulnerability of deep and shallow parts of a water supply well. Potential applications of the estimated travel time distributions include 1) improved management of well fields 2) development of pumping strategies and well screens minimizing the risk of pollution of drinking water wells, and 3) assessment of the adequacy of regulations established by authorities to protect valuable groundwater resources against pollution.   
The SANDEE campaign: Electrical effects during sand transport by aeolian processes in the Negev desert and implications for Mars
Authors: Katra Itzhak , Yair Yoav
Published: March 2020

The electrification of mineral sand/dust particles during aeolian processes is a well-documented phenomenon both in natural settings and in laboratory experiments. When in motion, small airborne dust particles collide with other suspended particles or impact the surface through the kinetic energy they acquire from the ambient wind. Field experiments will be conducted in conjunction with the AMEDEE-2020 Analog Mars Mission, planned for November 2020 in the Ramon Crater in southern Israel and led by the Austrian Space Forum. During SANDEE, we will deploy a portable wind-tunnel (Katra et al., 2016) at the site, and record particle movements in conditions that simulate sand storms of varying speeds. We will use local Negev desert, as well as Mars-simulant, soil samples that will be placed inside the wind-tunnel. We will measure particles' dynamic, mineralogical and electrical characteristics as they are blown by wind inside the tunnel.  A JCI 114 portable electric field detector will be used to to measure the amplification of the ambient electric field during sand movement. A vertical array of traps oriented along the wind direction will be used for sampling particles, in order to calculate the related sand fluxes and to analyze particle characteristics. The experiment will be repeated at night under dark conditions, in order to observe if light is emitted from electrified dust, due to corona discharges.

We expect that SANDEE will help decipher wind-speed/aerosol/electrical charge relationships. These have practical implications for future Mars landers, because airborne sand particles are likely to interfere with communications and also to impede the energy output of solar panels due to the electrical adhesion of charged aerosol.
Mountain waves penetrating into the mesosphere observed by airborne lidar
Authors: Kaifler Bernd , Dörnbrack Andreas , Mixa Tyler , Rapp Markus , Kaifler Natalie , Gisinger Sonja , Reichert Robert
Published: March 2020

We present observations by airborne lidar which were obtained over the southern Andes during the SOUTHTRAC campaign in September 2019. Operated onboard the German research aircraft HALO, the Airborne LIdar for Middle Atmosphere research (ALIMA) acquired high resolution temperature profiles in the altitude range 20-80 km. The data show signatures of mountain waves located at the mountain ridges, but often these signatures also extend several hundred kilometer downstream. While during the first days of the campaign mountain waves were able to penetrate into the mesosphere, observations obtained in the following weeks indicate a downward shift of the breaking zone from the mesosphere to the stratosphere which is consistent with the early breakdown of the polar vortex. Our data also indicate evidence for generation of secondary gravity waves within the breaking zone of the mountain waves.
Including climatic variability in stochastic rainfall for flood catastrophe modelling – The effect of ENSO and SOI in China
Authors: Salinas Jose Luis , Smith Rebecca , Li Shuangcai , Nicotina Ludovico , Hilberts Arno
Published: March 2020

Damages from flooding in China account on average for 60-70% of the total Annual Losses derived from natural catastrophes. The extreme rainfall events responsible for these inundations can be broadly categorised in two well differentiated mechanisms: Tropical Cyclone (TC) induced, and non Tropical Cyclone induced (nonTC) precipitation. Between 2001 and 2015, inland nonTC rainfall flood events occurred roughly with double the frequency as TC events. While TC events can be highly destructive for coastal locations, over the entire China territory nonTC flooding accounted for more than half of the total economic flood loss for events with significant socio-economic impact, highlighting the importance of the nonTC flooding mechanism on the regional and national scale.

Large-scale modes of climate variability modulate in different ways TC and nonTC induced precipitation, both in the frequency and the magnitude of the events. In a stochastic rainfall generation framework, it becomes therefore useful to model these two mechanisms separately and include their differentiated long-term climatic influences in order to fully reproduce the overall observed rainfall variability. This work presents results on the effect of ENSO and Southern Oscillation Index (SOI) values on seasonal rainfall in China, and how to include this climatic variability in stochastic rainfall for flood catastrophe modelling.
A depth-resolved framework for the coupling of sub-surface flows and surface gravity water waves
Authors: Ellingsen Simen Ådnøy , Weichert Stefan , Li Yan
Published: March 2020

This work aims to develop a new framework for the interaction of a subsurface flow and surface gravity water waves, based on a perturbation and multiple-scales expansion.  Surface waves are assumed of a narrow band δ (δ ), indicating they can be expressed as a carrier wave whose amplitude varies slowly in space and time relative to its phase. Using the Direct Integration Method proposed in Li & Ellingsen (2019), the effects of the vertical gradient of a subsurface flow are taken into account on the linear wave properties in an implicit fashion. At the second order in wave steepness ϵ, the forcing of the sub-harmonic bound waves is considered that plays a role in the primary equations for a subsurface flow.

The novel framework derives the continuity and momentum equations for a subsurface flow in two different formats, including both the depth integrated as well as the depth resolved version. The former compares with Smith (2006) to examine the roles of the rotationality of wave motions in the subsurface flow equations. The latter employs the sigma coordinate system proposed in Mellor (2003, 2008, 2015) and extends the framework therein to allow for quasi-monochromatic surface waves and the effects of the shear of a current on linear surface waves. Compared to Mellor (2003, 2008, 2015), the vertical flux/vertical radiation stress term in the proposed framework is approximated to one order of magnitude higher, i.e. O(ϵ2δ2).

References

Li, Y., Ellingsen, S. Å. A framework for modeling linear surface waves on shear currents in slowly varying waters. J. Geophys. Res. C: Oceans, (2019) 124(4), 2527-2545.

Mellor, G. L. The three-dimensional current and surface wave equations. J. Phys. Oceanogr., (2003) 33, 1978–1989.

Mellor, G. L. The depth-dependent current and wave interaction equations: a revision. J. Phys. Oceanogr., (2008) 38(11), 2587-2596.

Smith, J. A. Wave–current interactions in finite depth. Journal of Physical Oceanography, (2006) 36(7), 1403-1419.
Effects of land use history on heavy metals concentration in agricultural soils
Authors: Genova Giulio , Niedrist Georg , Della Chiesa Stefano , Tasser Erich , Borruso Luigimaria , Cesco Stefano , Mimmo Tanja
Published: March 2020

Intensive agricultural management can have significant impacts on soil properties. Such effects and their degree are often related to the history of land use and to the agronomic practices. When legacy soil data are missing, historical land use maps can help to describe how crop management might have changed the concentration of certain elements in soils. In this study, we prove how permanent crop management (vineyards and apple orchards) influenced heavy metal concentration in agricultural soils in South Tyrol, Italy. We selected areas where land-use change was unidirectional going from forests, grasslands and arable lands to apple orchards or vineyards. We hypothesize that the heavy metal accumulation in the soil starts when a parcel is converted to intensive permanent crops. This hypothesis allows us to see if there are any significant differences between parcels with a longer or shorter intensive agriculture history. We used approx. 6000 soil samples analyzed between 2006 and 2016 and coupled them with historical land use maps dating from the 1850s until today. Soils that have been cultivated as apple orchards or vineyards since the 1850s are characterized by higher concentrations of Cu. The oldest vineyards have much higher soil Cu concentrations than apple orchards of the same age with a median content of 342 mg kg–1 and 212 mg kg–1 of Cu respectively. Similar patterns, but with smaller extent can be described also for Zn concentration. Comparing the age of vineyards with today’s concentration we estimate an accumulation rate of 2.4 mg kg–1 year–1 of Cu. We conclude that historical land use maps are extremely helpful in understanding today’s soil characteristics especially with not degradable pollutants such as heavy metals. High concentrations of Cu in vineyards reveal the widespread and abundant use of this metal in viticulture for plant defense programs through time. The accumulation trend proves that further research and monitoring is needed to understand spatial and temporal pattern of Cu and Zn pollution in intensively managed permanent crops and to estimate their impact on taxonomical and functional fungal and bacterial diversity. These aspects are of pivotal role in determining the soil fertility levels of our cultivated soils.
Can we use citizen science to upscale soil data collection?
Authors: Schneider Christian , Döhler Susanne , Ohmann Luise , Wollschläger Ute
Published: March 2020

Citizen science approaches are still relatively rare in soil sciences. However, the Tea Bag Index (TBI) has been successfully implemented in projects all over the world.

Our citizen science project “Expedition ERDreich – Mit Teebeuteln den Boden erforschen” (EE) aims to upscale open soil data by applying the TBI as well as other soil assessment methods all over Germany. Beside the strong focus on creating awareness for soils and its functions we want to answer the following questions:

Is it possible to upscale citizen science projects to obtain large quantities of open soil data?

Are soil datasets from citizen science projects of sufficient quality to be used in soil science and for soil modeling?

The project will combine aspects of co-production as well as environmental education. Co-production means, soil data will individually be compiled by citizen scientists with the support of a team of scientists from a network of project partners. While conducting various soil assessments and experiments participating citizen scientists will be given background information and guidance meant to educate and to raise awareness about soils and soil quality.

We are aiming to involve a broad spectrum of citizens from various backgrounds, for example school children, students, farmers, forest owners, gardeners, municipal administrations, and of course soil scientists.

Within the project citizen scientists will submit turnover data from their location, together with information on the sampling sites, as well as information on soil properties like pH value, soil texture, and soil color. This information will be complemented with climatic and geo-scientific co-variables by the scientific project team.

So far we identified the following main challenges:

How can citizens from various backgrounds and in various geographical locations be addressed and involved in the project?

How do we get high quality soil data while still teaching soil awareness?

How do we address the complexity of soils in soil education?

How do we manage the quality of data and identify potential errors?

How do we communicate data management procedures to keep the project as transparent as possible?

What and how can we give back an added value to citizen scientists?

How do we involve citizen scientists in the scientific progress beyond collecting data and beyond the current projects timeframe?
Debris flow magnitude estimation based on infrasound and seismic signals
Authors: Schimmel Andreas , Cesca Matteo , Macconi Pierpaolo , Coviello Velio , Comiti Francesco
Published: March 2020

With the rapid socio-economic development of European mountain areas, the automatic detection and identification of mass movements like landslides, debris flows, and avalanches become more and more important to mitigate related risks by means of early warning systems. Past studies showed that such processes induce characteristic seismic and acoustic signals, the latter mostly in the infrasonic spectrum which can thus be used for event detection. Several investigations have already addressed signal processing and detection methods based on seismic or infrasound sensors. However, for developing an efficient warning system, not only the detection of events is important but also the identification of the event type (e.g. debris flow vs debris flood) and the estimation of its magnitude. So far, no method for such objectives has been developed which is based on the combination of both seismic and infrasonic signals.

This work presents a first approach to identify debris flows and debris floods magnitude based on the integration of infrasound and seismic data. First analysis shows that, for peak discharge, the use of infrasound amplitudes with a power curve fitting offers a good approach for finding an initial relationship between the recorded signals and this event parameter. For an estimation of the total volume, the discharge calculated with the relationship for peak discharge is integrated over the entire detection time of an event. Calculation of the peak discharge based on infrasound data offers a good approximation, but, for the calculation of the total volume, this method shows still a wide variance.

The method will be applied to seismic and infrasound data collected on three different test sites in the Alps: Gadria (South Tyrol, Italy), Lattenbach (Tyrol, Austria), and Cancia (Belluno, Italy).
Lithium isotopes as a probe of anthropogenic activities: Dommel River
Authors: Negrel Philippe , Millot Romain , Petelet-Giraud Emmanuelle
Published: March 2020

Lithium (Li) contents and isotopes were studied in the Dommel catchment, a small riverine system in northern Belgium and the southern part of the Netherlands discharging into the Meuse River downstream of Eindhoven. This covered surface and groundwaters developed onto sand and gravel in the catchment. The integrated investigation aimed at evaluating the potential of Li isotopes as effective tracers of anthropogenic activities in addition to efficiently trace water/rock interaction processes within a sandy environment. The d7Li values and Li concentrations were measured following standard chemical purification of Li using the cationic exchange resin protocol in a clean lab. Lithium-isotope compositions were measured with a Neptune MC-ICP-MS and Li concentrations by ICP-MS.

Dissolved lithium concentrations in the Dommel catchment span one order of magnitude ranging from 1.55 to 39.20 µg/L, with a mean concentration of 6.58 µg/L higher than the worldwide riverine average of 1.9 µg/L. The dissolved d7Li displays a large range of variation from +5.4‰ to +27.8‰. Part of the catchment can be impacted by smelter effluents with Li concentrations in the range 91 – 526 µg/L (mean value 288.36 µg/L) and a d7Li of around +25.6‰ and then dilution along the flowpath of the river basin.

To go further into the interpretation of the dataset in terms of using Li isotopes as a probe of anthropogenic activities, we first applied an atmospheric-input correction to waters both for Li concentration and d7Li as rainfall constitutes an important fraction of dissolved elements in the Dommel waters (8 to 100% of Li in waters is derived from atmosphere). Secondly, we determined and quantified the anthropogenic influence using δ7Li and mixing equations in the impacted parts of the catchment.
Spatial diversity and time variability of erosion and accumulation processes on the unconsolidated cliffs of the Wolin Island (Southern Baltic - Pomeranian Bay)
Authors: Winowski Marcin , Zwoliński Zbigniew , Kostrzewski Andrzej , Tylkowski Jacek
Published: March 2020

During the period of climate change affecting the increase in the frequency of extreme events, the problems of the functioning of the sea coasts become very important. The process of raising the World Ocean level directly threatens coastal areas which are inhabited by more than half of population.This situation is also observed on the Polish coast. The very intense and often uncontrolled tourist and economic development of this region requires the introduction of protection systems aimed at limiting the adverse changes caused by extreme processes. Anthropogenic coastal transformations commonly contribute to the modification of natural morphogenetic processes. As a result, the development of the coastal zone goes in an unknown direction.

The current problems related to the functioning of cliff coasts prompted the authors to conduct research on the impact of storm surges on the transformation of the morphology of the unconsolidated cliffs of Wolin Island. The research consisted of annual measurements of cliff morphology using terrestrial laser scanning (TLS) in the period 2013-2019. The obtained measurement series allowed to demonstrate spatial diversity and time variability of erosion and accumulation processes in various hydrometeorological conditions. Differential analyzes allowed to quantify of the sediment budget on different sections of the cliffs. Based on the proposed denudation indicators, spatial and temporal differentiation of cliff dynamics and efficiency was presented.
Transfer processes in the chalk critical zone – Multidisciplinary study of the undergound quarry of Saint Martin le Noeud
Authors: Valdés Danièle , Chen Ningxin , Dumont Marc , Marlin Christelle , Blanchoud Hélène , Fauchard Cyrille , Alliot Fabrice , Saydy Ayoub , Aubry Emmanuel , Guillemoteau Julien , Guérin Roger , Ribstein Pierre
Published: March 2020

The Chalk aquifer is a crucial, vital resource for water supply in France, Belgium and England. However, since several decades, this resource is threatened by high anthropogenic pressures: inducing a degradation of the groundwater’s quality.

The aim of our multidisciplinary study is to understand the transfer processes of the water and associated elements - solutes and contaminants (nitrate, pesticides) - throughout the critical zone (CZ) of chalk from the topsoil to the water table.

This study is focused on the underground quarry of Saint Martin le Noeud which is located in the Upper Cretaceous chalk layer of the Paris Basin. A layer of clay-with-flints covers the chalk of the quarry with a variable thickness. At a depth from 16 to 30m, the quarry is about 1200 m long and 150 m wide, giving a direct access to different groundwater compartments: (1) the Chalk water table through a series of 16 underground lakes, and (2) the vadose zone thanks to infiltration water percolating at the ceiling of the quarry. The set-up of this site allows to study the behaviors of both compartments.

Surface geophysical measurements: electrical resistivity tomography  and electromagnetic induction  mapping, have allowed to describe precisely the structure of the critical zone: in particular the geometry of the clay layer which has a variable thickness from 0 to about 5m.

The hydrodynamic and the quality of the groundwaters of both compartments (vadose zone and Chalk water table) have been characterized in time and space: (1) time series of flow percolation, water level, electrical conductivity and temperature, (2) geochemical analyses (major elements, nitrate, pesticides). The hydrodynamic and geochemical properties of the groundwaters vary spatially along the quarry highlighting different transfer processes.

Time series analysis and geochemical data allow to estimate the transfer velocities of the water and the contaminants and to precise the biogeochemical reactions (degradation, adsorption/desorption, storage …) that occurs in the CZ. These processes vary spatially depending on the properties of the CZ. The precise description of the clay layer compared to the groundwater behaviors allows to better characterize the infiltration processes. (1) a thin layer of clay induces a “diffuse infiltration”, low velocities, and low degradation of the pesticides in the subsurface, (2) a thick layer of clay induces a perched groundwater in the near-surface, degradation processes, concentrated infiltration and higher velocities.
Langmuir circulation due to shear flow over wavy topography
Authors: Akselsen Andreas H , Brostrøm Andreas , Ellingsen Simen Ådnøy
Published: March 2020

Langmuir circulations (LC) in their traditional form are large rolling fluid flow pattern created by the interplay of surface waves and a near-surface shear current, typically both created by the wind. A celebrated theory by Craik and Leibovich (1976) describes two kinematic mechanisms which cause instabilities which grow into Langmuir rolls, both involving only the shear of the flow and the kinematic driving of flow undulations by a wavy surface, but containing no direct reference to the wind as a driving force. The same kinematic processes are present also in boundary layer flow over a wavy bottom topography in almost perfect analogy.

We present a theory of Langmuir-like circulations created by boundary layer flow over a topography in the form of a regular pattern of two monochromatic waves crossing at an oblique angle. Thus, the Craik-Leibovich instability sometimes referred to as CL1 is triggered and the close analogy with surface waves allows us to follow the general procedure of Craik (1970).

A flow of arbitrary shear profile is assumed over the bottom topography. In the opposite limits of transient inviscid flow and steady-state viscous flow simple equations for the stream function in cross-current plane can be derived and easily solved numerically. For the special case of a power-law velocity profile, explicit leading-order solutions are available. This allows us to quickly map out the circulation response to different parameters: wavelength, crossing angle and wave amplitude. The study is supplemented with direct numerical simulations which verify the manifestation of Langmuir-like circulations over wavy geometries with a no-slip boundary condition.

References
Craik, A.D.D., A wave-interaction model for the generation of windrows. J. Fluid Mech. (1970) 41, 801-821.
Craik, A.D.D. & Leibovich, S. A rational model for Langmuir circulations. J. Fluid Mech. (1976) 73, 401-426.
Mesoscale Activity in the Eastern Mediterranean: Blending Altimetry with in situ observations
Authors: Baaklini Georges , Issa Leila , Brajard Julien , Fakhri Milad , Menna Milena , Taupier-Letage Isabelle , Mortier Laurent
Published: March 2020

Mesoscale to sub-mesoscale surface dynamics in the ocean is a key parameter, driving, for instance, the dispersion of pollutants emanating from heavily populated coastal areas for example. Estimating the surface velocity can be challenging especially when data is sparse. In [1], the authors developed a near real-time 3D-Var assimilation algorithm that blends in-situ Lagrangian drifters’ positions with altimetry data to improve the estimation of the surface velocity in the Eastern Levantine Mediterranean. The algorithm was tested near the Lebanese coast and in the case of an eddy between Lebanon and Cyprus. The objective of this work is to further validate the algorithm.

First, a Comparison with Ocean color satellite images shows that eddies’ shapes and location are more consistent after the assimilation of drifter data.Independent in-situ current-meter data provided from the EGYPT campaign are also used to validate the results of the algorithm in terms of velocity intensity and direction. The comparison shows an improvement of the estimated velocity, particularly in terms of direction.

We also address the question of extending the algorithm to a larger regional scale in the Eastern Levantine Mediterranean, which is subject to a high mesoscale activity but which is less densely observed than the western part.

 

[1] L. Issa, J. Brajard, M. Fakhri, D. Hayes, L. Mortier, P-M. Poulain. Modelling Surface Currents in the Eastern Levantine Mediterranean Using Surface Drifters and Satellite Altimetry. Ocean Modelling, May 2016. Doi: 10.1016/j.ocemod.2016.05.006