bluuebunny/crossref_metadata_2025 huggingface dataset:
Large landslides cluster along Patagonian Ice Sheet margin
Authors: Břežný Michal , Pánek Tomáš , Harrison Stephan , Schönfeldt Elisabeth , Winocur Diego
Published: March 2022

Deglaciation of mountain ranges promotes landslides of various scales and types, and many of them may present a major hazard. Traditionally, it is assumed that landslides are concentrated in the steepest, wettest, and most tectonically active parts of the orogens, where glaciers reached their greatest thickness. Based on our mapping of large landslides (>1km2) over an extensively large area of Southern Patagonia (~305,000 km²), we show that the distribution of landslides can have the opposite trend. The largest landslides within the limits of the former Patagonian Ice Sheet (PIS) cluster along its eastern margins occupying lower, tectonically less active, and arid part of the Patagonian Andes. In contrast to the heavily glaciated, highest elevations of the mountain range, the peripheral regions have been glaciated only episodically. However, a combination of glaciation, weak volcanic and sedimentary rocks, sufficient relief, and presence of large glacial lakes in the past, created favourable conditions for huge number of large landslides along eastern margin of PIS. We explain the scarcity of large landslides in the highest parts of the PIS by presence of strong granitic rocks and long-term glacial modification, that adjusted topography for efficient ice discharge. Our model is applicable only for large bedrock landslides, not for shallow slides and rock falls, which are abundant in the highest and western part of the Andes.
Dynamical analysis of large-scale 100-year precipitation events over Central European river catchments and their differences to less extreme events
Authors: Ruff Florian , Pfahl Stephan
Published: March 2022

Extreme, large-scale precipitation events can lead to extreme river floodings which are one of the most dangerous weather events for society when occurring in highly populated areas. However, the largest impacts are caused by very rare events with return periods on the order of 100 years. To do a quantitative and robust analysis of daily 100-year precipitation events, observational time series are typically too short. Therefore, an approach is applied here in which operational ensemble prediction data from the ECMWF are used to generate a large pool of simulated, but realistic daily precipitation events (corresponding to 1200 years of data) from which several 100-year events can be analysed. For five different major Central European river catchments, composite analyses show that 100-year precipitation events in all catchments are typically associated with an upper-level trough moving into Central Europe 24h to 48h before the occurrence of the events. During the 24h before the events, details in the progression of the trough and the location of the associated surface cyclone determine in which catchment extreme precipitation occurs. A comparison to composite analyses of less extreme precipitation events shows that dynamical mechanisms such as an amplified mid-tropospheric trough/cut off are more important for an intensification of precipitation events in the Danube and Oder catchments while in the Elbe, Rhine and Weser/Ems catchments thermodynamical mechanisms such as a larger moisture flux are more important. The question how a warmer climate will affect the dynamical processes of such extreme precipitation events will be investigated in a follow-up study.
Thermal tides in Martian atmosphere observed by EMIRS onboard the Hope spacecraft
Authors: Fan Siteng , Forget Francois , Smith Michael , Guerlet Sandrine , Badri Khalid , Atwood Samuel , Edwards Christopher , Christensen Philip , Deighan Justin , Al Matroushi Hessa , Bierjon Antoine , Liu Jiandong , Millour Ehouarn
Published: March 2022

Thermal tides are planetary-scale harmonic responses driven by diurnal solar forcing and influenced by planetary topography. Excited by solar heating absorbed by the atmosphere and energy exchange with surface, thermal tides grow in Martian atmosphere. These tides usually have large amplitudes due to the low heat capacity of Martian atmosphere, and dominate its diurnal variations. In this talk, we present results of the analysis of thermal tides in Martian atmosphere using temperature profiles retrieved using infrared spectra obtained by the Emirates Mars InfraRed Spectrometer (EMIRS) instrument onboard the Emirates Mars Mission (EMM) Hope spacecraft. The first set of data obtained during the mission science phase is selected, covering a solar longitude (LS) range 60° - 80° of Martian Year (MY) 36, which is a clear season without large dust storms. The novel orbit design of the spacecraft allows a full local time coverage to be reached within 10 Martian days, approximately ~5° of LS. It enables the analysis of diurnal temperature variations without the interference of seasonal changes, which was shown to be significant in previous studies. Wave mode decomposition is also applied to these diurnal variations, and amplitudes of other tide modes are derived. The results show good agreements with predictions derived using the Laboratoire de Météorologie Dynamique (LMD) Mars Global Circulation Model (GCM), except for a noticeable phase difference of the dominant diurnal thermal tide. This work provides valuable information on understanding diurnal variations in Martian atmosphere and inspires future advances of Mars GCMs.
The roughness length for momentum, heat and moisture for small water bodies (lakes, rivers, reservoirs)
Authors: Repina Irina , Artamonov Arseniy , Malkov Alexander
Published: March 2022

The question of the shallow water areas surface roughness properties remains largely open, despite numerous studies. The eddy covariance flux data collected from Gorkovskoe reservoir were used to analyse the variation of transfer coefficients and roughness lengths for momentum, heat and moisture. Results are compared with differ parameterization schemes. The drag coefficient and momentum roughness length rapidly decreased with increasing wind velocity, reached a minimum value in the moderate wind velocity and then increased slowly as wind velocity increased further. Under weak wind conditions, the surface tension or small scale capillary wave becomes more important and increases the surface roughness. The scales of roughness for momentum, heat, and moisture under moderate winds averaged 0.0006, 0.000073, and 0.000069 m, respectively. The ratio of the scales of roughness for temperature and for moisture was much greater than one for weak winds and decreased to values close to 1 for winds above the threshold value of about 3.0 m / s. A more efficient transfer of sensible heat in comparison with latent one under weak winds is due to the fact that temperature transfer played an important role in the formation of the buoyancy flow. On the basis of experimental data, parametrizations are proposed to determine the dynamic and scalar roughness length for small shallow water bodies and coastal zones. These parameterizations can be used in models of the Earth system. The work was supported by RFBR (grant N 20-05-00846, 19-35-60034) and RSF (grant N 21-17-00249).
Early stress detection in Austrian ecosystems with sun-induced chlorophyll fluorescence (AustroSIF)
Authors: Wohlfahrt Georg , Hammerle Albin , Duveiller Gregory , Migliavacca Mirco
Published: March 2022

When it comes to monitoring the health status of ecosystems, satellite-based remote sensing approaches hit a sweet spot in terms of global spatial coverage and temporal resolution. Conventional optical remote sensing approaches, however, offer limited potential for the early detection of ecosystem stress, as changes in ecosystem structure and function often need to be substantial in order to be detectable from the reflectance in the visible and near-infrared range of the energy spectrum.

Satellite-based remote sensing of sun-induced chlorophyll fluorescence (SIF) offers much greater potential to that end. Chlorophyll fluorescence is generated when solar energy absorbed by chlorophyll inside plant leaves is not used for photosynthesis or dissipated as heat, but is instead emitted at a slightly higher wavelength. Chlorophyll fluorescence thus results from fine-tuned changes in chlorophyll energy partitioning and SIF provides a highly sensitive optical signal, which allows the early detection of plant stress before symptoms become apparent in classical optical remote sensing indices.

Our previous work, however, has shown that in order to correctly diagnose whether or not plants are exposed to stress, SIF needs to be quantified jointly with the energy that is dissipated as heat and that this process can be accurately quantified on the basis of reflectance changes around the green peak, exploited by the so-called photochemical reflectance index (PRI). SIF data have become available from a few satellite platforms during the past couple of years, however their spatio-temporal resolution and signal-to-noise ratio is still unsatisfactory. A major step forward in data quality is expected from the upcoming ESA Earth Explorer mission FLEX, scheduled to launch in mid-2023.

The overarching goal of the AustroSIF project is to make present and future satellite-based sun-induced chlorophyll fluorescence measurements a sensitive and reliable means for the early detection of ecosystem stress by combining remotely sensed SIF and PRI. To that end we propose to simulate satellite measurements using ground-based, proximal sensing of active and passive chlorophyll fluorescence and hyperspectral reflectance. These measurements will be conducted in the field covering a wide range of ecosystems typical for Austria. Available satellite products will be used to test this approach at larger spatial and temporal scales. Process-based models will be used to disentangle the underlying drivers.

This contribution will detail the project structure and approach and provide first, preliminary results obtained during the first project year.
Optimization of ’cold’ laser ablation sampling for water isotopic analysis on ice cores
Authors: Malegiannaki Eirini , Gkinis Vasileios , Barbante Carlo , Dahl-Jensen Dorthe
Published: March 2022

The Beyond EPICA project for retrieving the Oldest Ice Core (1.5 Myr) in Antarctica aims at obtaining high resolution climate records and water isotopes will be one of the most important parameters investigated. Given the extremely thin nature of the annual ice core layers, as we get deep down to the core, analysis of such an ice core requires new adopted techniques on water isotopes with high accuracy and precision. Laser ablation (LA) is an established powerful technique used in various fields and it can also be applied in ice sampling serving a dual purpose: a.direct solid-gas transition and b. the smallest amount of sample possible is used for analysis and that makes LA a micro-distructive process. A new instrument which couples LA sampling with the established Cavity Ring Down Spectroscopy (CRDS) for water isotopic analysis is developed. This novel design will allow both fast gas phase sample collection directly from the ice sample and high quality water isotopic measurements. Particular focus was given in the LA system which consists of a High Energy femtosecond IR LASER and the optical elements that focus the LASER beam into the ice surface. The focusing lens system is placed inside a freezer, up above a motorized stage that accomodates the ice sample. An enclosure supplied with dry air flow was build around the optics and tested by the means of humidity experiments. Subsequent series of experiments with varying laser ablation parameters: pulse energy, repetition rate, ablation time, together with the ablated crater characterization allow the evaluation of LA efficiency in ice and thus the optimization of the parameters controlling the ablation mechanism. Understanding the LA mechanism will provide the knowledge to further develop the sampling procedure and efficiently control and guide the vaporized ice into a CRDS instrument for detection.
Global compilation of double seismic zones and their dependence on the intraslab stress field
Authors: Sippl Christian , John Timm , Schmalholz Stefan , Dielforder Armin
Published: March 2022

Double seismic zones (DSZs), parallel planes of intermediate-depth earthquakes inside oceanic slabs, have been observed in a number of subduction zones and may well be a ubiquitous feature of downgoing oceanic plates. Early focal mechanism observations from Japan and Alaska have shown downdip compressive events in the upper and downdip extensive events in the lower plane of the DSZ, which was interpreted as a signature of plate unbending at these depths. Such a pattern of compressive over extensive events has become a hallmark of DSZ seismicity, and some models of DSZ seismogenesis explicitely rely on an unbending-dominated intraslab stress field as a mechanism for deep slab hydration.

In this study, we show that the intraslab stress field in the depth range of DSZs is much more variable than previously thought. Compiling DSZ locations and mechanisms from literature, we observe that the “classical” pattern of compressive over extensive events, as in NE Japan, is only observed at about half of the DSZ locations around the globe. The occurrence of extensive mechanisms across both planes accounts for most other regions, whereas a “bending signature” of extensive over compressive events is not widely observed at all. To obtain an independent estimate of the (un)bending state of slabs at intermediate depths, we compute (un)bending estimates from slab geometries taken from the slab2 compilation of slab surface depths. We find no clear prevalence of slab unbending at intermediate depths, and the occurrence of DSZ seismicity does not appear to be limited to regions of slab unbending. Taking high-resolution focal mechanism information from the Northern Chile subduction zone as an example, we conclude that the intraslab stress field in subduction zones is primarily a superposition of (un)bending stresses and downdip extensive in-plane stresses. Depending on the sign (bending or unbending) and the relative contributions of these two principal stresses, an unbending signature as in NE Japan or a purely extensive pattern of focal mechanisms as in Northern Chile can emerge. We also consider possible additional contributing stresses that may further modify the intraslab stress field, such as friction along the plate interface and volume loss due to metamorphic phase changes.
The Gibraltar slab dynamics and its influence on past and present-day Alboran domain deformation: Insights from thermo-mechanical numerical modelling
Authors: Gea Pedro J. , Negredo Ana , Mancilla Flor de Lis
Published: March 2022

The origin and tectonic evolution of the Western Mediterranean region, specifically the Gibraltar Arc system, is the result of a complex geodynamic evolution involving the convergence of the Eurasia and Africa plates and the dynamic impact of the Gibraltar slab observed in tomographic studies. Although geologic and geophysical data collected in the last few years have greatly increased our knowledge of the Gibraltar Arc region, it is still unclear the mechanical links between the Gibraltar slab and the past deformation of the overriding Alboran lithosphere as well as present-day motion shown in detailed GPS observations. In this work, we use the code ASPECT to model the geodynamic evolution of the Alboran slab in 2D over the last 20 million years. The initial model setup simulates a vertical WE section at a latitude of about 36oN and represents the situation at 20 Ma, when the trench had already fully rotated to the southwest and the predominantly westward rollback of the Gibraltar slab started taking place. We conduct a parametric study varying the rheological parameters and the initial slab properties (dip angle and length) to properly fit the robust current slab features, particularly, its position and its curved morphology extending eastward. We show how after 20 Myr of model evolution, i.e. at present time, the slab pull appears to have a still significant influence on surface velocities. We find a westward surface motion in the Gibraltar arc caused by the negative buoyancy of the slab. These velocities increase westwards from 1 to 4 mm/yr consistently with geodetic observations. Our models roughly reproduce the Alboran basin evolution, initially developing the West Alboran Basin and then the East Alboran Basin. Finally, preliminary 3D models further support these results and properly the main trends of the coupled dynamics of the Gibraltar slab and Alboran basin evolution during the last 20 Myr.
Model Based Polynya: Deep water formation in the Southern Ocean
Authors: Barton Benjamin , Nurser George , Aksenov Yevgeny
Published: March 2022

Dense water is formed when sea ice around Antarctica drifts apart leaving open-water areas called polynyas. Both the processes of cooling sea water in contact with the atmosphere and salt accumulation in sea water during sea ice formation, lead to the sea water getting denser. The dense water formation in the oceans surrounding the Antarctic continent contributes to meridional overturning circulation, making it crucial to understand the changes in the Antarctic sea ice and oceans to improve model predictions. Using NEMO output from both a regional configuration and a coupled global configuration we ask how well are polynyas and deep water formation represented in the models? How do regional trends in sea ice affect the polynyas and deep water formation? In the model we find several types of polynya; including the open-water Great Weddell Sea Polynya and coastal polynyas. We have developed and applied an algorithm for classifying coastal polynyas based on sea ice concentration to identify and separate these from the open water polynya areas, in addition, we include sea ice thickness in the classification of coastal polynyas to select areas where the mixed-layer is deep, and surface salt flux is present. In the coastal polynyas the mixed-layer is deep and densification of the upper ocean is strong due to the surface salt flux. The Great Weddell Sea Polynya is also found to deepen the mixed-layer but the strong salt flux, found along the coast, is not present in the open-water polynya suggesting an alternative mechanism is taking place. The favourable ice divergence in the Weddell Sea builds over several years in both models but the Great Polynya itself does not reoccur after the 1980s. Coastal polynyas make up the largest area of the polynyas but show a negative trend in total area, possibly suggesting a diminishing role of these polynyas in future dense water formation. The study asserts different contributions of the two types of polynyas to deep water production.
Interpolation of GPR profiles (in 3D datasets) through Fourier Interpolation. Application to the case study of Roman Villa of Horta da Torre (Fronteira, Portugal)
Authors: Oliveira Rui Jorge , Caldeira Bento , Teixidó Teresa , Borges José Fernando
Published: March 2022

GPR data sometimes present subsampling problems that prevent an effective study about the existence of buried structures in an archaeological site. This is a frequent problem, related with the profile spacing used in the survey, when this is performed in parallel profiles to construct a 3D dataset. This difficulty can be lessened by decreasing the profile spacing, but that increases the survey time, or can be experimented in the data processing. INT-FFT algorithm is GPR data densification approach, complementary to the other standard operations, that allows to reconstruct missing data from the combined use of mathematical transforms and predictive filters. To calculate the missing signal, two requirements must be checked: (1) the data in the frequency domain must be limited in a range of values; and (2) must be able to be represented by a distribution of Fourier coefficients. Both conditions are verified in GPR data. Based on seismic trace interpolation, INT-FFT algorithm uses an open access routine (Suinterp, from Seismic Unix package) to interpolate the GPR profiles, that makes use of automatic event identification routines, through the calculation of spatial derivatives, to identify discontinuities in space from the detection very subtle changes in the signal, thus allowing for more efficient interpolation without artifacts or signal deterioration. The approach was successfully tested using GPR datasets from the archaeological site of Roman Villa of Horta da Torre (Fronteira, Portugal). The results show that there was an increase of the geometric sharpness of the GPR planimetry and has not produced any numerical artefacts. The tests performed to apply the methodology to GPR-3D data allowed to assess the interpolation efficiency, the level of recovery of missing data and the level of information lost when one chooses to increase the distance between profiles in the acquisition stage of the data.

 

Acknowledgment: The work was supported by the Portuguese Foundation for Science and Technology (FCT) project UIDB/04683/2020 - ICT (Institute of Earth Sciences) and by the INTERREG 2014-2020 Program, through the "Innovación abierta e inteligente en la EUROACE" Project, with the reference 0049_INNOACE_4_E.
Water Governing Systems: addressing conflicts between hydrological and institutional scales
Authors: Arjomandi A. Peyman , Seyedi Seyedalireza , Komendantova Nadejda
Published: March 2022

The human-generated systems typically meet biophysical ones within different geographical terrains. The space where those systems face each other is framed at the human-crafted and natural scales. Conventionally such sphere is a contestation field where various levels of contributing scales confront to embed a functional system. The water governing systems are as of the frequently debated of such systems. They resemble controversial evidence in the course of conflicts between hydrological and administrative/institutional scales. Indeed, due to the dominancy of human-determined objectives to the environmental requirements, the water governing systems have not considered reasonably the requisite of natural cycles in many areas. This issue produces externalities and mismatches between human-formulated and hydrological systems. To enhance the governance, there is a need to detect problems which arise from unfit of those systems in associated levels. Therefore, an inferential methodology which is able to capture and project the water (demand/supply) governing system state is being developed. The methodology encompasses incorporation of a system cost formulation approach. Besides, the system status in relation to microscopic configurations of its components is appraised through the method. This inscribed that a unique macroscopic state driven by a certain configuration is reflectable as a cost system bears in respect to its structure. Such cost is a theoretical estimate to measure the impact of a confiscated structure on the effectiveness of governing system. Correspondingly, the induced inefficiencies by the misfit between human-designed and biophysical systems are diagnosable through the comparison of system costs associated to pertinent structures/configurations.
Contribution to uncertainty evaluation associated with on-site infrasound monitoring systems
Authors: Demeyer Séverine , Kristoffersen Samuel , Le Pichon Alexis , Fischer Nicolas , Larsonnier Franck
Published: March 2022

In order to contribute to the improvement of the confidence and the quality of measurements produced by regional and international infrasound monitoring networks, this work investigates a methodology of uncertainty evaluation associated with on-site measurement systems. The proposed approach is applied to infrasound signals processed with TDOA (Time Difference of Arrival) propagation model which takes as inputs the wave parameters of the incoming signals (e.g. back-azimuth, horizontal trace velocity) recorded at the array elements. On one hand, relevant input uncertainties are investigated for propagation targeting the incoming signals (loss of coherence, noise), the instrumentation (microbarometers, calibration system, wind noise reduction system, environmental sensitivity) and the propagation model (sampling frequency and frequency band). On the other hand, relevant advanced output quantities of interest based on TDOA outputs are proposed. Statistical tools are then derived to evaluate the main contributions to the uncertainty associated with the advanced output quantities.
Trends in temperature and precipitation in high mountain areas in Spain from the Spanish Hig Mountain Climate Database
Authors: Sigro Javier , Pérez-Luque Antonio Jesús , Pérez-Martínez Carmen , Vegas-Vilarrubia Teresa , Esteban-Parra Maria Jesus
Published: March 2022

Mountain regions are areas characterized by great spatial variability in climate variables, due to the great differences in altitude, orientation and the abrupt topography that characterizes them. These features of the territory, together with a relative lower density of meteorological stations, make it difficult to characterize climate change in these areas.

This work describes the Spanish High Mountain Climate Database (SHMCDv1) consisting of daily quality controlled and homogenised records of maximum temperature, minimum temperature and precipitation for the territories that include the two highest altitude national parks in mainland Spain, the Sierra Nevada National Park (PNSN) and the Aigüestortes i Sant Maurici National Park (PNASM), and its area of ​​influence.

To build this database, 129 climatic series corresponding to the PPNASM area and 166 series in the PNSN area have been used, for the period between 1893 and 2020, obtained from various sources (AEMET, SMC, Climanevada database, LOOP Project). A systematic quality control has been applied to the series using the RClimdex-extraqc (see http://www.c3.urv.cat/data/manual/Manual_rclimdex_extraQC.r.pdf). This procedure has allowed the identification of 857 values considered erroneous, of which 10% has been recovered with the correct value. Its homogeneity has been tested and adjusted with a CLIMATOL homogenization method developed by J. Guijarro (2016) (see http://www.climatol.eu/index.html). 205 inhomogeneities have been detected and adjusted in the temperature series, which represents an average of 2 inhomogeneities for each series.

In total, thermo-pluviometric series have been composed for a set of 98 meteorological stations, 27 of them located above 1500 meters of altitude.

Sen’s estimator of the slope have been used to estimate the temperature and precipitation trends corresponding to low mountain areas (<1500 m altitude) and high mountains (> 1500 m altitude) are calculated and analyzed to determine if there are differences in the evolution of recent temperature or precipitation due to altitude and between both mountain areas.

This work has been done thanks to funding from MINECO and MITECO, through the projects LACEN-CLI (ref: 2476-S/2017), MEROMONT (ref: CGL2017-85682-R) and Smart EcoMountains (LifeWatch-2019-10-UGR-01).
On pyFIRI implementation: non-disturbed non-auroral ionospheric D-Region model for the Python ecosystem
Authors: Zolotov Oleg , Knyazeva Maria
Published: March 2022

Many ionospheric studies require the global state of the Earth’s ionosphere D-Region. It is valuable for HF-band radio-waves propagation problems and as the lower boundary and/or initial conditions for the numerical modeling. A robust D-Region model is also required as the reference state that may be used for data interpretation, assimilation, to fill missed values, or as a convenient representation of observations. The existing trend of Python scientific infrastructure application for the ionosphere and space weather modeling triggers the need for a D-Region model for the Python ecosystem.

FIRI-2018 is a mature model of the Earth’s non-auroral non-disturbed ionospheric D-Region. It is the successor of FT-2001, a model included into IRI-2016, which is the de-facto standard model of the Earth’s ionosphere. To an end-user, the FIRI-2018 model was provided by Friedrich et al. (2018, https://doi.org/10.1029/2018JA025437 ) as a set of pre-calculated reference electron density profiles for the Northern Hemisphere. pyFIRI (https://doi.org/10.1016/j.softx.2021.100885) is the Python3 package built on top of those reference profiles. Our presentation aims to describe the principal features of the pyFIRI package and to highlight our preliminary results on FIRI-2018 extrapolation to the Southern Hemisphere.

Acknowledgement. Authors are grateful to Dr. Martin Friedrich for the fruitful discussion and detailed consulting on the FIRI-2018 model. We acknowledge Dr. Martin Friedrich, Dr. Klaus Torkar, and Christoph Pock for making FIRI-2018 data freely available, and for kind permission to adopt these data for the pyFIRI package. Without this, the pyFIRI package would not be possible to develop. 
Estimation of energy loss of internal solitary waves over an isolated obstacle
Authors: Terletska Kateryna , Maderich Vladimir
Published: March 2022

Simulations of internal solitary waves (ISW) of the first mode over the isolated obstacles of various shapes:  triangles, semicircle and rectangles of different lengths are presented.  The influence of height, length and shape of the obstacle on the transformation of ISW and energy dissipation was investigated. A two-layer free surface water system with upper and bottom layer thicknesses h1 and h2 and densities ρ1 and ρ2, respectively, and water depth H was considered.  It was carried out set of 42 numerical experiments with both ISW of elevation and depression types. The results of simulation were compared with the results of laboratory experiments. It is shown that the blocking parameter B  [1] (that is a dimensionless parameter equal to the ratio of the lower layer above the obstacle to the wave amplitude) is useful for describing the type of interaction and estimation of energy loss.  The transformation of large amplitude ISW over a triangular obstacle differs from the corresponding interaction with the semicircle obstacle. Internal boluses formed in the case of semicircle or rectangle obstacle are 1.5 - 2 times larger than in the case of a triangular obstacle. As a result, energy dissipation and corresponding mixing in the case of ISW transformation over semicircle and a rectangular obstacle is greater than in the case of a triangular ones. Maximum energy losses can reach 42% in the case of a rectangular obstacle. Energy losses increase with increasing length of the obstacle. Thus, we can conclude that topographic effects, namely the influence of shape and geometric characteristics of underwater obstacles have a significant impact on the dissipation of mechanical energy. 

 

[1]  T. Talipova , K. Terletska, V. Maderich, I. Brovchenko, K. T. Jung, E. Pelinovsky and R. Grimshaw  Internal solitary wave transformation over the bottom step: loss of energy. // Phys. Fluids, 2013, 25, 032110
6000 years of winter climate variability revealed by a speleothem record from East-Central Europe
Authors: Dragusin Virgil , Ersek Vasile , Fleitmann Dominik , Ionita-Scholz Monica , Onac Bogdan P.
Published: March 2022

Holocene reconstructions of winter climate in East-Central Europe (ECE) are scarce, although several studies have brought more seasonal insights through the study of pollen in lake sediments, δ18O and deuterium excess from an ice cave deposit, as well as speleothem trace elements.

Here we present the δ18O record of stalagmite PU-2 from Urşilor Cave (W Romania) that could shed further light onto ECE Holocene hydroclimate variability for the past 6000 years. This previously published stalagmite benefits now from a more detailed age-depth model and an increased temporal resolution, to an average of 15 years across the whole record. More importantly, following recent monitoring studies, it was concluded that the δ18O signal in the cave drip water is representative of winter climate conditions.

In East-Central Europe there is a significant correlation between the winter temperature and the East Atlantic teleconnection pattern (EA), as this region witnesses higher than average temperatures during the positive phase of EA. The North Atlantic Oscillation teleconnection pattern (NAO) is known to modulate winter precipitation in the European realm, and many NAO reconstructions have sought to identify its variability in the past.

To investigate the drivers behind winter climate dynamics in the region surrounding the cave and across Europe, we compare our data with other speleothem winter temperature and rainfall records from Europe and the Levant. Further, we examine their variability on a complex time-evolving relationship with the coupled NAO/EA patterns.
Assessment of the hydrochemical integrity of deep geothermal aquifers - Lessons from bottled water producers
Authors: Baumann Thomas
Published: March 2022

Geothermal ressources for heat and power generation are an integral part of the transition from fossil fuels to clean and sustainable energy and have been successfully developed in the North Alpine Foreland Basin since the 2000s. The timeframe since the first exploration activities is rather short and data on induced changes in the aquifer is scarce. It might be a good idea to take a look at the development classical groundwater ressources for comparison, even more so, if the geothermal facility also includes a net withdrawal for eg. medical or wellness applications.
Most deep groundwater aquifers are of vital importance but strongly limited as ressources for drinking water. Depletion of these aquifers is easy to assess and usually handled well in the legislative procedure. The development of the hydrochemical state and the possible occurrence of mobile persistent trace pollutants, on the other hand, is hard to predict. Here, the current assessment framework which is based on the protection of the aquifer by impermeable layers falls short: together with groundwater renewal the age structure of the aquifer has to change. Old groundwater is replaced by more recent groundwater. Substances with a similar transport behaviour as wateritself will sooner or later show up in these deep groundwater ressources. Examples from bottled water producers show that the development from a state without any traces of anthropogenic substances to a the first occurrence is sharp and irreversible.
Future development concepts for deep groundwater aquifers have to take the age structure of the aquifer into account when defining acceptable withdrawal rates, groundwater protection zones and technical operations which influence the integrity of the protecting layers.
We present a conceptual assessment and monitoring concept for deep groundwater aquifers which includes the risks posed by unconventional uses of the impermeable layers (foundations, corroded wells, geothermal, ...).
Landslides in the Tovel Valley: shaping the landscape and ruling the people
Authors: Rossato Sandro , Martin Silvana , Ivy-Ochs Susan , Viganò Alfio , Campedel Paolo , Rigo Manuel
Published: March 2022

Landslides are very efficient in shaping mountain landscapes, modifying the drainage pattern of the valleys, forcing people to adapt, react or counter them. In particular, valleys in the southern side of the Alps are narrow, with very steep slopes, and often have been inhabited since prehistoric times.

The Tovel Valley is located in the Adamello Brenta Nature Park in the northern Brenta Dolomites, near a lake (Tovel lake) that is famous for its, at times, red colour. This valley can be found in the central-eastern Southern Alps, along the western margin of the Adriatic indenter. Here, tectonic forces started to act in the Late Cretaceous, during the initial phases of the Alpine orogenic history, and are still active today. Moreover, the Trentino Region is one of the most seismically active sectors of Northern Italy, with significant historical and instrumental earthquakes typically clustered in very good agreement with tectonic structures. N-S oriented vertical strike-slip faults determined the shape of the Tovel Valley, favouring the occurrence of prominent source detachment scarps on the eastern valley side. The Tovel lake, whose origin is still debated if due to glacial processes or landslide events, records a sudden rise in its level, testified by the drowning of a submerged forest dated by dendrochronology at 1597 AD. This event is interpreted as due to a minor rockfall, which blocked the outflow channel on the north-eastern lakeside. This event had direct consequences on people living in the area, that were forced to find timber elsewhere, but also older, and larger, rock avalanches likely affected people living in the valley.

Whilst Tovel lake has been studied for a long time, the blocky deposits of the Tovel Valley gathered much less attention. By means of field mapping, remote sensing and cosmogenic 36Cl exposure dating, we reconstruct the age and the evolution of the blocky deposits that occupy large areas of the valley bottom, with implications directly connected to the formation and evolution of the Tovel lake. Landslide deposits cover an area of ~5 km2 and are composed of seven bodies distributed at different elevations, ranging from ~1900 to ~900 m a.s.l. Their total volume is estimated at 200–280 Mm3 of debris made of Dolomia Principale and Calcare di Zu Formations. Detachment areas are mainly located along the eastern valley side, with six out of seven events that can be classified as rock avalanches.
Observations and preliminary results of hydrothermal activity on the shallowing coastlines of the Dead Sea, Israel 
Authors: Lazar Michael , Goodman-Tchernov Beverly
Published: March 2022

The Dead Sea basin, the lowest and one of the saltiest places in the world, is a tectonically active 150 km long and 15–17 km wide terminal pull‐apart basin located along the southern Dead Sea plate boundary. As a result of the combined effect of climate change and anthropogenic intervention, lake levels have been dropping at an alarming rate of over 1 m per year during the last few decades. Due to this rapid decline, a number of hydrothermal springs have become exposed on land along the western shore of the lake. However, once subaerial they are typically categorized as sinkholes, despite the fact that they are a different geological feature that results from a different mechanism. Generally, hydrothermal springs within the Dead Sea are understudied. This, coupled with rapidly lowering lake levels leaves a considerable knowledge gap in how this system is changing and responding with time. Previous studies have proposed the presence of underwater springs or seeps based on temperature anomalies and acoustic blanking observed on high-resolution seismic reflection profiles. Direct observations of nearshore springs were obtained by a team of scientific divers over 10 years ago who examined water chemistry and microbiology. Their study suggested that submarine springs must be connected to a high-pressure flow system, which is able to penetrate the fresh-saline interface in the Dead Sea, probably along tectonic faults and cracks. Fractures in the sediment would force variable rates of flow depending on width of the fractures, thus possibly leading to the different chemical compositions found in the underwater springs over a short distance.  More recently, a follow up set of underwater and on land surveys were conducted in a similar, adjacent spring system, providing insight into the changes that have occurred over the past decade. This study will present a summary of past studies as well as insights gained from this most recent research. 
Permafrost Evolution on the British Isles during the Last Deglaciation.
Authors: Toechterle Paul , Edwards R. Lawrence , Gunn John , Atkinson Tim , Murton Julian B. , Luetscher Marc , Moseley Gina E.
Published: March 2022

Globally, near-surface permafrost is likely to warm, thin or disappear in many areas subject to future climate warming and wetting, creating a positive atmospheric feedback where the permafrost is rich in carbon. Unfortunately, substantial uncertainty exists as to the extent and timing of thawing in response to atmospheric forcing. Cryogenic cave carbonates (CCCs),  a recently described type of speleothem, precipitate when cave ice forms and thus provide opportunities to constrain periods when permafrost was present at a given cave site. Here, we present a unique dataset comprising 38 230Th/U ages of CCCs from two caves in the Mendips, southwest England (51°N), and two caves in the Peak District, central England (53°N), all of which are currently ice-free. Whilst many ages are clean, reliable and high precision, the accuracy of those containing initial 230This improved greatly by constructing isochrons and applying further statistical methods.

The ages of CCCs reveal two distinct periods of isothermal permafrost conditions, peaking during i) the early Bølling–Allerød interstadial at approximately 14,463 ± 145 yBP* and ii) the late Younger Dryas around 11,719 ± 229 yBP. Such isothermal conditions (i.e., where values of mean annual ground temperature are commonly a fraction of a degree below 0°C and exist through much of the depth profile of permafrost) are thought to represent the later stages of permafrost warming prior to its disappearance. We attribute this isothermal, disequilibrium permafrost evolution during the last deglaciation of the British–Irish Ice Sheet to climatic variations linked to North Atlantic sea-ice extent and seasonality.

*years before 1950
Multi-proxy speleothem records attest to Central-Eastern Europe hydro-climate variability during MIS 3, the LGM, and the Holocene 
Authors: Warken Sophie F. , Riechelmann Dana F.C. , Fohlmeister Jens , Schröder-Ritzrau Andrea , Spötl Christoph , Jochum Klaus P. , Scholz Denis , Constantin Silviu , Frank Norbert
Published: March 2022

Speleothems from well-monitored Cloşani Cave (Romania), have provided excellent records of past rainfall amount and European winter hydro-climate variability (Warken et al., 2018). Here we present new data allowing to extend the precipitation history of Central-Eastern Europe back to the Last Glacial Maximum (LGM) as well as MIS 3. High-precision 230Th/U ages show that the two analysed speleothems (C09-1 and C09-2) grew nearly continuously during the past 20 ka, with only one growth interruption between c. 11 and 9.7 ka BP. In addition, C09-2 also covers the Dansgaard/Oeschger (D/O) Stadials/Interstadials 16 to 14 between 60 and 52 ka BP. Consistently with previous results, the speleothem proxies (δ18O and δ13C values, as well as laser ablation ICPMS trace element profiles) provide a comprehensive picture of local and regional hydro-climate variability on centennial to glacial/interglacial timescales.

Over the course of the record, all proxies reveal millennial-scale features associated with prominent transitions during MIS 3, i.e., D/O events 16 to 14, as well as during the deglaciation, i.e., the Bølling-Allerød (BA) and Younger Dryas (YD). Local wetness as indicated by Mg/Ca ratios exhibits large variability, including pronounced swings between dry conditions during MIS 3 interstadials, and wetter conditions during stadials. After speleothem growth re-initiated at 20 ka BP, Mg/Ca ratios indicate a progressive drying until 15 ka BP, followed by an interval with enhanced variability from the Late Glacial to the Early Holocene. During the subsequent mid to late Holocene, from 8 ka BP to present, the local hydroclimate was characterized by relatively stable conditions. This dataset thus provides new insights into Central-Eastern European precipitation variability, and possibly also into its linkages to the North Atlantic realm.

References:

Warken, S.F., Fohlmeister, J., Schröder-Ritzrau, A., Constantin, S., Spötl, C., Gerdes, A., Esper, J., Frank, N., Arps, J., Terente, M., Riechelmann, D.F.C., Mangini, A., Scholz, D., (2018). Reconstruction of late Holocene autumn/winter precipitation variability in SW Romania from a high-resolution speleothem trace element record. Earth and Planetary Science Letters 499, 122-133. DOI: 10.1016/j.epsl.2018.07.027
The role of maize root exudates to availability of N source in different forms in top- and subsoils
Authors: Ai Juanjuan , Banfield Callum , Shao Guodong , Zamanian Kazem , Spielvogel Sandra , Dippold Michaela
Published: March 2022

Nitrogen (N) availability is a main constraint to plant productivity, especially when vegetation relies largely on subsoils, which contain considerable N resources but in low availability. Rhizodeposition can promote N cycling by stimulating microbial growth and activity and thus induces the release of mineral-bound nutrients and accelerates decomposition of soil organic matter (SOM). However, many specific processes how root exudates interact with distinct N forms altering their subsoil mobilization still remain unclear. We hypothesize that the lower microbial activity but higher sorption capacity of subsoils induces subsoil-specific N dynamics. To disentangle this, we added four N sources (free NH4+, sorbed NH4+, urea and plant residues with identical total N content) into top-and subsoils. We quantified microbial processes regulating mineral and organic N availability in top-and subsoils by simulating rhizosphere condition via application of collected root exudates in a well-controlled microcosm experiment. Our results showed that neither growth of the total microbial community, nor shift in the community composition occurs based on maize root exudate amendment resembling a daily exudation amount. However, we observed a clear increase in microbial activity and activation of organic nutrient mobilizing mechanisms (e.g. enzyme activation), which was in most cases higher in sub- than in topsoils. This suggests that root exudates may not be of highest relevance for topsoil nutrient mobilization. In contrast, high root exudation is of much higher relevance for crops, which aim to mobilize a significant proportion of their nutrients from subsoils. We could demonstrate that subsoil communities were well capable of using litter-derived N, especially if root exudates accelerate overall activity and N cycling in subsoils. N incorporated from plant litter is successively recycled in microbial bio-and necromass following the initial degradation. Consequently, if breeding for deep-rooting crops with nutrient uptake from subsoils shall be promoted in the future, it is essential to ensure that these crops deep roots have a high root exudation to activate the highly C limited microbial communities of the subsoil.
Seismic Evidence for Partial Melt Below Tectonic Plates
Authors: Bodin Thomas , Debayle Eric , Durand Stephanie , Ricard Yanick
Published: March 2022

The seismic low-velocity zone (LVZ) of the upper mantle is generally associated with a low-viscosity asthenosphere that has a key role in decoupling tectonic plates from the mantle. However, the origin of the LVZ remains unclear. Some studies attribute its low seismic velocities to a small amount of partial melt of minerals in the mantle, whereas others attribute them to solid-state mechanisms near the solidus or the effect of its volatile contents. Observations of shear attenuation provide additional constraints on the origin of the LVZ. On the basis of the interpretation of global three-dimensional shear attenuation and velocity models, here we report partial melt occurring within the LVZ. We observe that partial melting down to 150–200 kilometres beneath mid-ocean ridges, major hotspots and back-arc regions feeds the asthenosphere. A small part of this melt (less than 0.3 per cent) remains trapped within the oceanic LVZ. Melt is mostly absent under continental regions. The amount of melt increases with plate velocity, increasing substantially for plate velocities of between 3 centimetres per year and 5 centimetres per year. This finding is consistent with previous observations of mantle crystal alignment underneath tectonic plates. Our observations suggest that by reducing viscosity melt facilitates plate motion and large-scale crystal alignment in the asthenosphere.