bluuebunny/crossref_metadata_2025 huggingface dataset:
Run-up of breaking focused waves on a beach studied experimentally in a large scale facility and numerically using hybrid FNPT-RANS model 
Authors: Saincher Shaswat , Venkatachalam Sriram , Didenkulova Ira
Published: March 2021

The feasibility of generating long period waves using a piston-type wavemaker was comprehensively demonstrated in [1] for the Großer Wellenkanal (GWK) at 1:100 scale. These included regular waves, elongated solitons, N-waves as well as time-series pertaining to earthquake tsunamis (namely the 2004 Indian Ocean and 2011 Tohoku tsunamis).

In the companion paper [2], the aforementioned long-period waves were simulated using fully nonlinear potential theory (FNPT) and the Korteweg-de Vries (KdV) equations and compared with GWK measurements. It was established that the FNPT and KdV models accurately predicted long-distance evolution of these waves as well as dispersion-induced splitting of elongated solitons and N-waves to the form of undular bores. In addition, the run-up characteristics of the “2009 Samoa tsunami” record and elongated solitons were also studied in [2]. The semi-numerical procedure adopted in [2] for run-up estimation was limited to long non-breaking waves. However, the experimental data collection included also violently breaking focused waves of a smaller period.

In the present work, we apply IITM-RANS3D to simulate the run-up characteristics of breaking focused waves based on experiments carried out in the GWK using a 1:6 slope. An in-house, Reynolds-Averaged Navier-Stokes model (IITM-RANS3D) has been recently developed and hybridized with the in-house potential code IITM-FNPT2D. The RANS framework allows for complete description of breaking wave hydrodynamics and FNPT-hybridization ensures energy preservation for long-duration wave simulations. The run-up problem is considered as a multiphase flow where the beach is physically modelled as a high-viscosity fluid. The simulations would provide valuable insight into the run-up characteristics of breaking bores at large scale as viscous and aeration effects are fully accounted for in the RANS model.

REFERENCES

[1] S. Schimmels, V. Sriram, I. Didenkulova, Tsunami generation in a large scale experimental facility, Coastal Engineering 110, 32-41 (2016).

[2] V. Sriram, I. Didenkulova, A. Sergeeva, S. Schimmels, Tsunami evolution and run-up in a large scale experimental facility, Coastal Engineering 111, 1-12 (2016). 
Single-layer multi-periods? A Case Study of the Enclosure Site of Khirbet el Mastarah, Jordan Valley 
Authors: Ackermann Oren , Anker Yaakov , Ben-Shlomo David , Hawkins Ralph , Porat Naomi
Published: March 2021

Dating of desert enclosure sites is challenging, as they have minimal diagnostic elements. Moreover, these sites are composed primarily of a single layer, which raises the question of whether they are of single or multi-period settlements. 

The current research aims to answer this question by assessing a group of enclosures in the Jordan Valley. The sites were previously surveyed and dated to the early Iron Age (ca. 1200–1000 BCE), and linked to tribes of Israelite settlement in the region. We present new excavations and OSL ages from Khirbet el Mastarah that indicate several periods of usage, and the possible construction and occupation of the enclosures during the following periods: 

Iron Age II (2570±220 yr), Late Hellenistic or Early Roman periods (2090±150 yr and 2120±160 yr), Late Byzantine (1410±200 yr, 1370±150 yr), Early Islamic and Islamic/Abassid periods (1000±90 yr and  1080±110 yr). Another indication that emerges from the results is that different enclosures were used at various locations during various periods, and are still used by local herders. Therefore, the site has horizontal chronology rather than vertical stratigraphy, and is characterized by a single-layer with multi periods of spatial usage.
Detection of an enhanced stratospheric aerosol layer above Europe one year after the eruption of the volcano Raikoke
Authors: Tomsche Laura , Marsing Andreas , Jurkat-Witschas Tina , Lucke Johannes , Kaiser Katharina , Schneider Johannes , Borrmann Stephan , Voigt Christiane
Published: March 2021

Extreme volcanic eruptions inject significant amounts of sulfur-containing species into the lower stratosphere and sustain the stratospheric aerosol layer which tends to cool the atmosphere and surface temperatures.

During the BLUESKY campaign in May/June 2020, the aerosol composition and its precursor gas SO2 were measured with a time-of-flight aerosol mass spectrometer onboard the research aircraft HALO and with a atmospheric chemical ionization mass spectrometer onboard the DLR Falcon. While SO2 was slightly above background levels in the lower stratosphere above Europe, the aerosol mass spectrometer detected an extended aerosol layer. This sulfate aerosol layer was observed on most of the HALO flights and the sulfate mixing ratio increased significantly between 10 and 14 km altitude. Back trajectory calculations show no recent transport of polluted boundary layer air or ground-based emissions into the lower stratosphere. Therefore, we suggest that the stratospheric sulfate aerosol layer might be attributed to the aged stratospheric plume of the volcano Raikoke in Japan. In June 2019, Raikoke injected huge amounts of SO2 into the lower stratosphere, which were converted to sulfate and contributed to the stratospheric aerosol layer. This decaying volcanic aerosol layer was observed with the aerosol mass spectrometer over Europe a year after the eruption. The long-term volcanic remnants enhance the total stratospheric aerosol surface area, facilitate heterogeneous reactions on these particles and provide additional cloud condensation nuclei in the UTLS. They further offset some of the reduced sulfur burden from aviation that was observed during the COVID-19 lockdown in 2020.
The sensitive and highly time resolved airborne measurements of composition and size of stratospheric aerosol from an explosive volcanic eruption help to better constrain sulfur chemistry in the lower stratosphere, validate satellite observations near their detection threshold and can be used to evaluate dispersion and chemistry-climate models on long-term effects of volcanic aerosol. 
Observations on Seychelles-Chagos Thermocline Ridge (SCTR) upwelling during April-May 2019 in the western tropical Indian Ocean
Authors: Noh Suyun , Nam SungHyun
Published: March 2021

The Seychelles-Chagos Thermocline Ridge (SCTR) in the western tropical Indian Ocean is known as a region of off-equatorial upwelling contrasting to equatorial upwelling in the Pacific and Atlantic where the most wide open-ocean upwelling occurs corresponding to ascending branch of one of the meridional overturning cells in the Indian Ocean, yet detailed stratification, upwelling intensity, and dynamics of SCTR upwelling variability are still poorly understood. Here, we present observational results on the SCTR upwelling based on ship-based data collected during April-May 2019 as a part of the Korea-US inDian Ocean Scientific Research Program (KUDOS). The upwelling structure is confirmed from 20 ℃ and 10 ℃ isotherms (D20 and D10) shoaling up in the center of SCTR, from 200 m to 100 m (D20) and from 600 m to 400 m (D10), respectively. Horizonal divergence at the upper 250 m within an 1° by 1° area in the SCTR center (8 °S, 61 °E) estimated from currents measurements along the boundaries (1.0 x 10-3 Sv) supports a mean upwelling intensity of 7.0 x 10-3 m day-1 (1.0 x 10-3 Sv divided by the area). The upwelling intensity generally decreases with depth but shows multiple peaks within the upper water column, yielding the maximum peak (5.0 x 10-2 m day-1) at 60 m and the minimum peak (1.4 x 10-2 m day-1) at 230 m, with negative peaks (downwelling) at depths around 100 and 210 m. Our results on the observed structure and intensity of SCTR upwelling are discussed in comparison to time-varying local wind stress curl-driven Ekman pumping, D20-based Seychelles Upwelling Index (SUI), and Indian Dipole Mode Index (DMI). Detailed observations on the structure and intensity of SCTR upwelling presented here have important implications on time-varying SCTR upwelling (e.g., weakened upwelling peaked in fall 2019) and climate via meridional overturning circulation in the upper Indian Ocean.
Internal dose rate in quartz grains: Implications for luminescence dating 
Authors: Poręba Grzegorz , Szymak Agnieszka , Moska Piotr , Tudyka Konrad , Adamiec Grzegorz
Published: March 2021

This study assesses how internal dose rate in quartz grains impacts luminescence dating.  In 2018, the Gliwice Luminescence Laboratory implemented innovative μDose system which combines advantages of alpha and beta counting measurement techniques with additional radioactive identification capabilities. The device allows measurements of small samples and results verification with an independent high-resolution gamma spectrometry method. 

All measurements of internal dose rate were made on  pure quartz grains after standard chemical pretreatment. Grains with diameters between 125 and 200 μm were selected for measurements. This material was dried and grounded to approx. 20 μm using a planetary ball mill prior to measurements on the μDose systems.  

Internal dose rate reported here is particularly important because of low (about 0.8-0.9 Gy/ka) or very low (0.4-0.6 Gy/ka) external dose rates. Internal dose rate in quartz grains in our measurements is a significant fraction of the total dose rate, often exceeding 10%. Ignoring this correction would make luminescence ages in our study artificially older.

Presented results were obtained with support of Polish National Science Centre, contract number 2018/30/E/ST10/00616 
Development of a Triple-Reflection Compact Time-Of-Flight Mass Spectrometer for Lunar Polar Exploration
Authors: Saito Yoshifumi , Yamamoto Naoki , Yokota Shoichiro , Kasahara Satoshi
Published: March 2021

In order to investigate the presence (and amount) of the water (ice) molecules in the regolith 1 to 1.5 m below the lunar surface, a compact neutral particle mass spectrometer is under development. This neutral particle mass spectrometer is designed to install on a Moon rover, and it will perform mass analysis of neutral gas generated in the heating chamber. This mass spectrometer not only aims to measure the amount of water molecules included in the lunar regolith but also identify the atoms, molecules and their isotopes up to mass number 200 with mass resolution as high as 100.

The mass spectrometer under development is a reflectron that is a Time-Of-Flight mass spectrometer. A standard reflectron consists of an ion source, ion acceleration part, free flight part, ion reflection part and an ion detector. Ionized neutral particles are accelerated in the two-stage ion acceleration part by a pulsed high voltage whose pulse timing is used as a start signal. The accelerated ions enter into the free flight part and reflected in the single-stage ion reflection part. Reflected ions again fly through the free flight part and detected by a detector. Ion mass is determined by the time difference between the start signal and the particle detection.

In order to increase the mass resolution as much as possible within the allocated volume, we have decided to modify the standard reflectron by adding a second reflector that enables triple reflections and doubles the flight length. This newly designed triple-reflection TOF mass spectrometer can be operated also as a standard reflectron by changing the electric field configuration. Since the triple-reflection reduces the detection efficiency while increasing the mass resolution, the single reflection mode is used as a complementary mode where the detection efficiency is higher while the mass resolution is lower.

  
Comprehensive analysis and separation of river hydrograph using the GrWat R package
Authors: Kireeva Maria , Samsonov Timophey , Rets Ekaterina
Published: March 2021

River hydrograph analysis provides valuable information about temporal and spatial variability of the river discharge. One of the most imporant operations is separation of hydrograph, which aims at decomposing the total streamflow into components. Numerous approaches for hydrograph separation have been developed to date. Most of them traditionally separate the streamflow into general quickflow and baseflow components, but it is also possible to obtain more specific quickflow separation with subdivision into genetic components, such as seasonal snowmelt, rain, thaw etc. We present the general framework for river hydrograph analysis and separation provided by newly released GrWat package, which has been developed during several years. The framework includes a simple tabular data model for representation of hydrograph and climatic (temperature and precipitation) daily data needed for separation of the quickflow into genetic components; spatial analysis operations for automatic extraction of climatic data from reanalysis datasets covering the river basin; automated interpolation of missing data considering the autocorrelation; fast implementation of multiple algorithms for hydrograph separation; computation of more than 30 interannual and long-term characteristics of separated hydrograph components; scale-space transformation for hierarchical decomposition of the hydrograph; high-quality plotting and reporting of the results of analysis. One of the prominent features of the framework is a powerful algorithm for genetic hydrograph separation, which is capable of not only extracting the baseflow, seasonal, thaw and rain flood components, but also to cut the short-time rain floods which complicate the shape of the seasonal flood. The baseflow separation is performed on the first stage and can be initialized by any of the baseflow separation algorithms available in the package. On the second stage the quickflow is separated into genetic components. Such modular structure provides the flexible way to experiment with different combinations of algorithms and to select the approach wich serves best to the goal of the analysis and specific features of the hydrograph.

The study was supported by the Russian Science Foundation grant No. 19-77-10032
Effects on the solubility and the volatile release from magmatic intrusions
Authors: Vulpius Sara , Noack Lena
Published: March 2021

The process of fractional crystallization within a magma body has an influence on the solubility and thus on the associated release of volatiles. Nevertheless, this mechanism is widely neglected in the literature. Due to cooling of an intrusion, nominally anhydrous minerals precipitate from the melt. These minerals mainly incorporate elements that are compatible with their crystal lattice. Since volatiles such as H2O and CO2 behave like incompatible elements, they accumulate in the remaining melt. At a certain point, the melt is saturated and the exsolution of the volatiles initiates. The solubility is determined by several parameters like the lithostatic and the partial pressure, the temperature and the melt composition. 
In this study, we investigate the effect of these parameters as well as the impact of fractional crystallization on the solubility and the related volatile release. We focus on the exsolution of H2O and CO2 from basaltic magma bodies within the lithosphere. To determine the fate of the accumulating volatiles, we compare the density of the developing liquid phase (volatiles and residual melt) with the density of the host rock. If the host rock has a higher density, the liquid phase will ascent either directly to the surface or to shallower levels of the crust. Furthermore, we take into account the possibility that hydrous minerals (e.g., amphibole) are precipitated during fractional crystallization or due to a reaction with the surrounding rock. 
How representative is global terrestrial wind speed from in-situ observations?
Authors: Zhou Lihong , Azorin-Molina Cesar , Zeng Zhenzhong
Published: March 2021

Since long-term in-situ observations over land reflect to some extent the climatic conditions of the area where they are located, observed wind speed are used for many applications, e.g.: to estimate wind energy resources, to quantify the role of winds on evapotranspiration rates, or to assess the thermal response of lakes; among many others. However, it is not well-known whether site-specific station averages are representative of wind speed conditions in the corresponding areas; in fact, few studies have explored this so far. Here, we will investigate wind speed data from observation stations and reanalysis products. By comparing the relationships of the magnitude, inter-annual variability, and long-term trends in these two datasets at various spatiotemporal resolutions, e.g., 3⁰×3⁰, 5⁰×5⁰, continental and global scale, etc., we will better understand the representativeness of wind speed changes at in-situ stations in different regions. This study will help to further reveal the uncertainties in the representativeness of studies using station-based wind speed observations.
Exploring MLT momentum fluxes and horizontal wind gradients over the Andes at four different latitudinal sectors using multistatic configurations
Authors: Conte J. Federico , Chau Jorge , Janches Diego , Fritts David , Liu Alan , Qiao Zishun , Salvador Jacobo , Hormaechea José
Published: March 2021

The middle atmosphere over the southern Andes is known as one of the most dynamically active regions in the world. Previous studies have investigated wave dynamics at mesosphere and lower thermosphere (MLT) altitudes within this region, but only a handful of them have made use of continuous measurements provided by specular meteor radars (SMRs). Furthermore, it was only until recently that MLT horizontal wind gradients were estimated for the first time using a multistatic SMR network located in southern Patagonia. By observing larger amounts of meteors from different viewing angles, multistatic SMRs allow estimating not only more reliable momentum fluxes, but also parameters such us relative vorticity. In this work, we explore and compare MLT wave dynamics at low and middle latitudes around the Andes Mountain range. For this purpose, we investigate mean momentum fluxes and horizontal wind gradients obtained using four multistatic SMR networks: SIMONe Peru (12° S), CONDOR (30° S), SIMONe Argentina (50° S) and MMARIA-SAAMER (54° S).
Modelling the tropospheric and stratospheric sulfur isotopes in a column model for volcanically quiescent periods
Authors: Nagori Juhi , Nechita-Bândă Narcisa , Shinkai Masumi , Danielache Sebastian , Röckmann Thomas , Krol Maarten
Published: March 2021

It is debated how much stratospheric sulfate aerosol (SSA) in volcanically quiescent times is replenished by carbonyl sulfide (COS) oxidation products. The atmospheric COS budget is also currently uncertain, with missing sources and sinks. Isotopic analysis can be used to allocate the missing sources of COS and also to further constrain the relevance of COS to SSA. The measured tropospheric isotopic signature of COS (δ34S) ranges from 10-14 ‰ (Kamezaki et al., 2019; Angert et al.,2019; Hattori et al., 2020; Davidson et al., 2020), whereas SSA δ34S is constrained by only one single measurement at 18 km of 2.6 ‰ (Castleman, 1974). We use an atmospheric column model to constrain the COS isotopic budget and understand the contribution of COS to sulfate. We find that the COS tropospheric signal is determined by the signatures of its precursors (carbon disulfide, CS2, and dimethyl sulfide, DMS) and fractionation during plant uptake and oxidation. Photolysis of COS is important in the stratosphere; the isotopic signal of COS propagates through sulfur dioxide (SO2) to sulfate in the stratosphere. The model can reproduce δ34S between 1-5 ‰ in the lower stratosphere, which encapsulates the observations from Castleman (1974).

References

Angert, A., Said-Ahmad, W., Davidson, C., & Amrani, A. (2019). Sulfur isotopes ratio of atmospheric carbonyl sulfide constrains its sources. Scientific reports, 9(1), 1-8.

Castleman Jr, A. W., Munkelwitz, H. R., & Manowitz, B. (1974). Isotopic studies of the sulfur component of the stratospheric aerosol layer. Tellus, 26(1-2), 222-234.

Davidson, C., Amrani, A., & Angert, A. (2020). Tropospheric carbonyl sulfide mass-balance based on direct measurements of sulfur isotopes.

Hattori, S., Kamezaki, K., & Yoshida, N. (2020). Constraining the atmospheric OCS budget from sulfur isotopes. Proceedings of the National Academy of Sciences, 117(34), 20447-20452.

Kamezaki, K., Hattori, S., Bahlmann, E., & Yoshida, N. (2019). Large-volume air sample system for measuring 34S∕ 32S isotope ratio of carbonyl sulfide. Atmospheric Measurement Techniques, 12(2), 1141-1154
Modeling the Physiological Responses of a Desert Shrub to Rainfall Pulses in an Arid Environment
Authors: Wu Chuandong , Liu Hu , Yu Yang , Zhao Wenzhi
Published: March 2021

A physically-based model for soil-plant-atmosphere continuum (SPAC) is parameterized and evaluated against field-measured physiological responses of a desert shrub, Haloxylon Ammodendron (HA), to rainfall pulses in a desert environment in northwestern China. Despite its simplicity, the model was successfully employed to assess the complexity and uncertainty involved in the physiological responses of HA following pulsed rainfall events. Through modelling efforts, we report a systematic evaluation of the non-linear relationship between the physiological responses of HA and pulse magnitude or antecedent moisture. The results show that following the rainfall pulses, the modeled daily transpiration and assimilation rates either stayed the same or decreased monotonically with water stress. However, the stomatal conductance (gs) and photosynthetic rate (An) responses were relatively weaker when compared to the increase in water potential. We found that rainfall events with <5 mm cannot induce any substantial response of An (Δ<4μmol m-2s-1), and at least 13 mm of rain is required to increase An by 10 μmol m-2s-1. Significant responses of water use efficiency (WUE) were not even discernible from viewing the simulation. Our analysis reproduced the judgements with a certain uncertainty that HA is basically a kind of drought resistant species, it tends to have a more conservative water-use strategy and thus a safer photosynthetic behavior. The inverse–texture hypothesis is much more clearly supported by the modeling experiments, suggesting that soil texture drives differences in the effects of pulses on the magnitude and sensitivity of the physiological responses of plants, and the interaction between rainfall and soil texture may lead to the preferred acquisition and use of pulsed precipitation by HA. The modelling work and findings in this study is likely to shed light on the quantitative understanding of the physiological behavior of other plants in water-limited environments.
Global long-term land surface temperature for NOAA AVHRR: extension from 1981-2000 to 1981-2020
Authors: Ma Jin , Zhou Ji
Published: March 2021

As an important indicator of land-atmosphere energy interaction, land surface temperature (LST) plays an important role in the research of climate change, hydrology, and various land surface processes. Compared with traditional ground-based observation, satellite remote sensing provides the possibility to retrieve LST more efficiently over a global scale. Since the lack of global LST before, Ma et al., (2020) released a global 0.05 ×0.05  long-term (1981-2000) LST based on NOAA-7/9/11/14 AVHRR. The dataset includes three layers: (1) instantaneous LST, a product generated based on an ensemble of several split-window algorithms with a random forest (RF-SWA); (2) orbital-drift-corrected (ODC) LST, a drift-corrected version of RF-SWA LST at 14:30 solar time; and (3) monthly averages of ODC LST. To meet the requirement of the long-term application, e.g. climate change, the period of the LST is extended from 1981-2000 to 1981-2020 in this study. The LST from 2001 to 2020 are retrieved from NOAA-16/18/19 AVHRR with the same algorithm for NOAA-7/8/11/14 AVHRR. The train and test results based on the simulation data from SeeBor and TIGR atmospheric profiles show that the accuracy of the RF-SWA method for the three sensors is consistent with the previous four sensors, i.e. the mean bias error and standard deviation less than 0.10 K and 1.10 K, respectively, under the assumption that the maximum emissivity and water vapor content uncertainties are 0.04 and 1.0 g/cm2, respectively. The preliminary validation against in-situ LST also shows a similar accuracy, indicating that the accuracy of LST from 1981 to 2020 are consistent with each other. In the generation code, the new LST has been improved in terms of land surface emissivity estimation, identification of cloud pixel, and the ODC method in order to generate a more reliable LST dataset. Up to now, the new version LST product (1981-2020) is under generating and will be released soon in support of the scientific research community.
Progress on absolute dating of ice cores with Argon isotopes
Authors: Orsi Anais , Crotti Ilaria , Jacob Roxanne , Landais Amaelle , Fourré Elise
Published: March 2021

In the search for very old ice, finding the age of the ice is a key parameter necessary for its interpretation. Most ice core dating method are based on chronological markers that require the ice to be in stratigraphic order. However, the oldest ice is likely to be found at the bottom of ice sheets, where the stratigraphy is disturbed, or in ablation areas, where the classical methods cannot be used. Absolute dating techniques have recently been developed to provide new constraints on the age of old ice, but their development in the context of ice cores is limited by the large sample size required. Here, we discuss the analytical performances of a new technique for 40Ar dating, which allows us to provide a reliable age with 80g of ice rather than 800g, as previously published. We present an application to the dating of the bottom of the TALDICE and Dome C ice cores. This method represents a significant advance for its application to the very precious ice at the bottom of ice cores.
CO and O2 in the Martian atmosphere with ACS NIR onboard TGO.
Authors: Fedorova Anna , Lefèvre Franck , Trokhimovskiy Alexander , Korablev Oleg , Montmessin Franck , Forget Francois , Olsen Kevin , Luginin Mikhail , Lomakin Alexander , Ignatiev Nikolay , Belyaev Denis , Patrakeev Andrey , Alday Juan
Published: March 2021

The molecular oxygen (O2) and carbon oxide (CO) are minor constituents of the Martian atmosphere with the annual mean mixing ratio of (1560 ± 60 ppm) and (673 ± 2.6 ppm), respectively (Krasnopolsky, 2017). Both are non-condensable species and their latitudinal variations are induced by condensation and sublimation of CO2 from the polar caps that result in enrichment and depletion and seasonal variations are following the total CO2 amount in the atmosphere.

The Atmospheric Chemistry Suite (ACS) is a set of three spectrometers (-NIR, -MIR, and -TIRVIM) intended to observe Mars atmosphere onboard the ESA-Roscosmos ExoMars 2016 Trace Gas Orbiter (TGO) mission (Korablev et al., 2018). The near infrared channel (NIR) is a compact spectrometer operating in the range of 0.7–1.7 µm with a resolving power of λ/Δλ ~ 25,000. It is designed to operate in nadir and in solar occultation modes. The simultaneous vertical profiling of the O2 and CO density at altitudes of 10-60 km based on 0.76 µm and 1.57 µm bands, respectively, is a unique feature of the ACS NIR science in occultation. In this work we present the seasonal and latitudional distribution of the O2 and CO mixing ratios obtained for period of 2018-2020 (MY34 and35) and the comparison with the LMD General Circulation model. We report the averaged mixing ratio for CO of ~950 ppm and for O2 of~1800 ppm at low altitudes (~20 km). Also, we detected extremely enriched CO layer at 10-15 km in the southern polar region at Ls=100-200° both for MY34 and MY35.
Bacterial in situ-reproduction and colonization of sediments occurring in a limestone mine
Authors: Zaccone Claudio , Puglisi Edoardo , Terribile Fabio , Squartini Andrea
Published: March 2021

A 3-m thick sediment was found in a limestone mine located in the southern part of the Gargano Promontory, Apulia region (south of Italy), at a depth of ca. 25-30 m from the current ground level.

Samples from 5 layers were analysed by X-ray diffraction (XRD), elementar analysis (CHNS), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Microbial DNA was also extracted and bacterial diversity analysed by PCR amplification and Illumina High-Throughput Sequencing (HTS) of the V3-V4 hypervariable regions of 16S rRNA.

Preliminary data showed that these sediments formed by subsequent weathering of carbonates and silicates, either by in situ oxidation or by dissolution followed by migration and reprecipitation, rather than during the accumulation of shallow marine sediments occurring between the middle Pliocene and the lower Pleistocene, when the extreme western sectors of the Apulian foreland underwent strong subsidence.

The main mineral compounds occurring in the 5 layers, from the top to the bottom, were the following: calcite (80%) and clay minerals in sample #1, goethite (75%) and hematite in sample #2, manganese (66%) and iron oxides in sample #3, almost exclusively goethite in sample #4, and calcite (71%) and clay minerals in sample #5.

From the microbiological point of view, drawn from a 16S metabarcoding amplicons sequencing analysis, these 5 layers appear to cluster in three groups: a) the uppermost layer (sample #1), dominated by a single and abundant taxon of Arthrobacter sp., which includes species known for  the capability of calcite precipitation; b) a middle layer (including samples #2 and #3), without prevailing abundances and less consistent occurrences across replicates, which featured members of the Oxalobacteraceae family and of the Methylophilus genus. Their closest matches in Genbank subjects included isolates from habitats such as calcium carbonate (moonmilk) muds in percolating waters within caves, mine tailings and other groundwater microcosms; c) a bottom layer (samples #4 and #5), showing an oligarchic situation and high abundances of bacteria but different from the ones that prevailed in the top layer and including members of the Nocardioidacaeae family. Also for these sequence queries, the closest GenBank subjects include cases with calcium carbonate-precipitating capabilities isolated from cave and groundwater sediments or former mining sites in studies on iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations.

Overall, such a distribution suggests that, both in the top and bottom layer, different communities would have undergone in situ-reproduction and colonization exploiting metabolically the substrate, whereas the mid layers would have received bacterial convection by passive transport of percolating waters.
Magnetic properties of PM in indoor/outdoor domestic environments 
Authors: Da Silva Leite Aruã , Macouin Melina , Rousse Sonia , Leon Jean-François , Drigo Loïc , Ivan Ferreira da Trindade Ricardo
Published: March 2021

The finer fraction of the particulate matter (PM) is the most harmful health wise, as it has more capacity to reach deeper parts of the respiratory system. Among other constituents, PM also contains iron oxides, allowing for the use of magnetic methods in its investigation as proxies for the whole of PM. Those methods present advantages in comparison to traditional ones, being quick, cost effective and sensible to investigate iron oxides among PM. 

To better understand the risks related to PM exposition in the domestic context, the assessment of magnetic parameters may be used in outdoor and indoor environments, giving us information on the concentration of iron oxides (and consequently, PM) and its dispersion from one environment to the other. 

We developed a citizen sciences experiment in the city of Toulouse, France. Tree barks were used as bio-collectors. Garlands composed of tree bark pieces were distributed to the population in May-2019, and placed in both indoors and outdoors of flats and homes to capture PM. They were retrieved after one year. Measurement of magnetic susceptibility, ARM, SIRM, S -ratio and estimation of superparamagnetic concentration were performed. A total of 86 bio-collectors kits were successfully analyzed. The preliminary results indicate a higher concentration of iron oxides outdoors, with a mean difference between outdoor and indoor measurements of 6.58x10-9m3/kg and 1.38x10-5Am2/kg in susceptibility and SIRM respectively. The concentration of the SP fraction also follows this trend of higher outdoor values. The magnetic mineralogy is mostly dominated by low coercivity magnetite-like carriers.

 

 
Bridging the failure of surface asperities to the macroscopic rupture energy during the onset of frictional sliding
Authors: Barras Fabian , Aghababaei Ramin , Molinari Jean-François
Published: March 2021

The onset of sliding between two rough surfaces held in frictional contact arises through the nucleation and propagation of rupture fronts, whose dynamics has been shown to obey the elastodynamics of a shear crack. By analogy with the fracture energy controlling the growth of brittle crack in intact material, a frictional rupture is governed by an associated rupture energy. In the context of earthquakes, this rupture energy is expected to control the nucleation and the transition from an accelerating slip patch or localized perturbation to a propagating seismic rupture. The microscopic origin of this rupture energy and its relation to the microcontacts topography remain however unsettled.

In this context, this study aims at bridging the macroscopic description of friction to the failure of contacting asperities and frictional wear prevailing at smaller scales. Recent studies demonstrated how the failure of two contacting asperities arises either by plastic deformation or brittle failure of their apices depending on whether their contact junction is respectively smaller or larger than a characteristic length scale. In this study, we investigate numerically how the different failure mechanisms of microcontact asperities impact the nucleation and propagation of frictional rupture fronts.

At a macroscopic level, we study the ability of an interface to withstand a progressively applied shearing, i.e. its frictional strength, while at the microscopic scale, we observe how the failure process develops across the microcontact junctions. We highlight how the microcontacts topography significantly impacts the nucleation and frictional strength, even when comparing interfaces with identical macroscopic properties and rupture energy. We present how the characteristic length governing microcontacts failure can be used to select which details of the surface roughness are homogenized along the tip of a nucleating slip front. Combining the approach proposed in this work with models solving normal contact between rough surfaces will open up new prospects to study the strength and rupture energy of frictional interfaces at the onset of sliding.
A multiproxy reconstruction of vegetation dynamics in the Eastern Alps (Switzerland): combining paleoecological and paleogenetic approaches.
Authors: Dziomber Laura , Gurtner Lisa , Leunda Maria , Schwörer Christoph
Published: March 2021

Current and future climate change is a serious threat to biodiversity and ecosystem stability. With a rapid increase of global temperatures by 1.5°C since the pre-industrial period and a projected warming of 1.5-4°C by the end of this century, plant species are forced to either adapt to these changes, shift their distribution range to higher elevation, or face population decline and extinction. Today, there is an urgent need to better understand the responses of mountain vegetation to climate change in order to predict the consequences of the human-driven global change currently occurring during the Anthropocene and maintain species diversity and ecosystem services. However, most predictions are based on short-term experiments. There is, in general, an insufficient use of longer time scales in conservation biology to understand long-term processes. Palaeoecological data are a great source of information to infer past species responses to changing environmental factors, such as climate or anthropogenic disturbances.

The last climate change of a similar magnitude and rate as projected for this century was the transition between the last Ice Age and the Holocene interglacial (ca. 11,700 years ago). By analyzing subfossil plant remains such as plant macrofossils, charcoal and pollen from natural archives, we can study past responses to climate change. However, until recently it was not possible to reconstruct changes at the population level. With the development of new methods to extract ancient DNA (aDNA) from plant remains and next generation DNA-sequencing techniques, we can now infer past population dynamics by analyzing the genetic variation through time. Ancient DNA might also be able to reveal if species could adapt to climatic changes by identifying intraspecific variation of specific genes related to climatic adaptations.

We are currently investigating a palaeoecological archive from a high-altitude mountain lake, Lai da Vons (1991 m a.s.l), situated in Eastern Switzerland. We are presenting preliminary macrofossil, pollen and charcoal results to reconstruct local to regional vegetation and fire dynamics with high chronological precision and resolution. In a next step, we will use novel molecular methods, in order to track adaptive and neutral genetic diversity through the Holocene by analyzing aDNA from subfossil conifer needles. The overarching goal of this large-scale, multiproxy study is to better understand past vegetation dynamics and the impact of future climate change on plants at multiple scales; from the genetic to the community level.

 
Conceptual model assessment of vegetation vulnerability to fire in SE Spain: severity and recurrence effects using Google Earth Engine
Authors: Peña Molina Esther , Marino del Amo Eva , Tomé Morán José Luis , Moya Navarro Daniel , de las Heras Ibañez Jorge
Published: March 2021

Wildfires have an important influence on desertification’s advance. Due to climate change, it is foreseeable that the number of wildfires and their burned surface will increase. The alteration of fire regimes and its effect on the vegetation recovery, soil properties and fuel structure are one of the imperative research needs at this time to be able to establish vegetation vulnerability limits or ranges and vegetation resilience against forest fires.

The aim of this study is to implement a conceptual model assessment of vegetation vulnerability and-or vegetation resilience after forest fires. It starts with a bibliographic research to establish the concepts and definitions of vulnerability and resilience, with which undertake the practical case of generating a model or an indicator of resilience and vulnerability from the effects that the severity and recurrence of forest fires have had in two large forest fires in the southeast of Spain in 1994 and 2017. From the processing of the satellite scenes within the Google Earth Engine platform, several spectral vegetation indices are calculated such as NDVI, NBR or dNBR and four zones belonging to the Habitat type 9540 of Annex I of Directive 92/43/EEC are digitalized depending on their fire severity and fire recurrence: not burned in 1994 and burned in 2017; burned in 1994 and not burned in 2017; burned in both 1994 and 2017 and, finally, not burned in both 1994 and 2017. From this design a time series graph is made to evaluate the vegetation recovery rate in each of the areas.

Once this is done, it is possible to check how many years each zone requires to recover the spectral values before wildfires, which zones require more time to get recovered and, depending on the severity values, which zones should be treated to improve its natural recovery. With all the results, the last process is to create the cartography for identifying the most vulnerable zones depending on their ecological characteristics so we can be aware and do preventive treatments to increase the resilience of those most vulnerable areas in future extreme events. Google Earth Engine has proved to be an extremely useful tool for managing big datasets due to its high-level processing, versability and reproducibility, because once the script is done it is way easy to update the current study or to implement the same case of study in other areas to compare both results.
Assessing Nitrogen Legacies in Western Europe
Authors: Musolff Andreas , Ehrhardt Sophie , Dupas Rémi , Kumar Rohini , Ebeling Pia , Fleckenstein Jan H.
Published: March 2021

Intensive agricultural land use have introduced vast quantities of nutrients such as reactive nitrogen (N) to soils and subsequently to groundwater and surface waters. High nitrate concentrations are still a pressing issue for drinking water safety and aquatic ecosystem health e.g. in Europe, although fertilizer inputs have been significantly lowered in the last decades. This is partly due to a slow response of riverine nitrate concentrations to changes in nitrogen inputs attributed to N legacies in catchments. N can be stored organically bound as a biogeochemical legacy in soils or can be slowly transported as nitrate in groundwater forming a hydrologic legacy. Legacy can thus lead to a net retention of N in catchments and to substantial time lags in the response to input changes. Here, we systematically explore legacy effects over a wide range of catchment in the Western European countries France and Germany. We are making use of long observational time series of nitrate concentration in 238 catchments covering 40% of the total area of France and Germany. We apply a Weighted Regression on Time, Discharge, and Season (WRTDS) to derive continuous daily flow-normalized concentrations and loads. The temporal pattern of concentration and loads at the catchment outlet is compared to the N input time series evolving from agricultural N surplus, atmospheric deposition and biological fixation. We found that on long-term catchments retain on average 72% of the N input. Time lags between input and output were successfully explained by a lognormal transport time distribution. The modes of these distributions were found to be rather short with a median mode of 5.4 years across all catchments. Based on this data-driven assessment only the fate of N in the catchments is hard to assess as denitrification in soil and groundwater can lead to similar observations as the storage of N in legacies. Focusing on the mobile part of N that is exported by catchments, we estimate that a substantial amount of N is still stored in the subsurface that will be released in the coming years. We therefore analyzed how catchment nitrate export will evolve under the scenario of a total cut down, reduced or constant future N inputs. We report the expected timescale of reaction to implemented measures to help tackling this pressing water quality problem.
Investigation of Extreme Rainfall Patterns around Antalya and Muğla Cities in Türkiye by Using C Band Doppler Radar Data
Authors: Yapıcı Emir , Öztopal Ahmet , Erdi Erdem
Published: March 2021

As is known, rainfall varies spatially and temporally with regard to intensity and frequency. Floods, related to extreme rainfall cases, cause stress on geophysical system and community if climate change is considered. For this reason determining of extreme rainfall patterns is very important. While obtaining three dimensional status of hydrometors in atmosphere is not possible only by using ground station networks, it is possible by using weather radars. Therefore, weather radars provide significant contribution to studies about getting cloud and rainfall patterns. The aim of this study is to investigate spatial patterns of extreme rainfall events in Antalya and Muğla cities which are located on the Mediterranean coast of Türkiye. Firstly, hourly rainfall (RN1) and rain rate (SRI) products of 2 C band doppler radars and raingauge data between 2015 and 2020 will be processed by a software named MeteoRadar which is developed by İstanbul Technical University. It is capable of reading, decoding, parallel processing and visualization. Secondly, extreme rainfall patterns will be obtained over 2 study areas. Finally, after validation by using raingauge data, results will be discussed in detail.

Key Words: Antalya, Extreme rainfall, MeteoRadar, Muğla, RN1, SRI, Weather radar.
Imaging the spatio-temporal variations in deep tremor activity using cluster analysis techniques
Authors: Opris Anca , Kundu Sumanta , Hatano Takahiro
Published: March 2021

More than 15 years of seismic observations on slow earthquakes are available for the Nankai and Cascadia regions, due to the high density of seismic stations and constant improvements. It was observed that deep tremor activity exhibits highly non-Poissonian behaviour, consisting of short-period bursts separated by long periods of inactivity, as well as significant spatial variations throughout a tectonic region (Obara, 2011). Tremor activity in these regions has shown episodic behaviour with different recurrence interval. Modelling the space-time variations can help the unified understanding of the phenomenon. Catalogues with more than 30.000 (Idehara et al., 2014) and 130000 LFE’s (Mizuno et al, 2019) are available for the world tremor databese. If we consider LFE’s source as a spatial correlation structure which is evolving in time, in order to reveal the characteristics of this structure, we used the Grassberger Procaccia algorithm to calculate the combined correlation dimension (Tosi et al.,2008) of tremor activity (Cc (r, τ)), at both local and regional scale. The integral representation is shown as contour map (facilitating the possibility of using machine learning algorithms based on image processing for identifying the characteristic image of each tremor patch). Thus, implementing machine learning methods for LFE cluster analysis is required. After performing the cluster analysis, we could identify the specific spatio-temporal behaviour of each of the tremor patches in the studied regions, not just the features which were described in previous studies, such as recurrence intervals for short-term slow slip events (Idehara et al., 2014), tremor migration (for monitoring purposes), but also new features which could be used for forecasting.

 