bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrodynamics in the near-wake of cylindrical obstacles in a turbulent open channel flow
Authors: Fernandez Théo , Schnauder Ingo , Eiff Olivier , Blanckaert Koen
Published: March 2022

The research concerns the hydrodynamic processes around obstacles of cylindrical shape installed across an open channel flow at a subcritical Reynolds number of ReD = 1 x 104 (based on the cylinder diameter), and the forces exerted by the turbulent flow on these obstacles. Based on field measurements performed on the Plizska River, Poland, this study is mainly on cylinders representing large wood trunks that traverse a river. 

The first aim of the study is to reproduce the flow pattern around an inclined single tree trunk of quasi constant diameter and without branches measured in the field and to enable a more detailed analysis of the underlying turbulent flow processes. These field measurements have shown that horizontal near bank recirculation zones, scour below the trunk and plunge scour overtopping it occurred.

The second aim is to compare the mean flow and vortex shedding around inclined and horizontal cylinders across the flow. The effects of inclined and horizontal cylinders on the flow field are very different: the former create a higher variability in flow processes.  These configurations differ in gap width below the cylinder and in approach velocity, as the inclined cylinder is located at different elevations in the bottom boundary layer. Both parameters affect the vortex shedding frequency and the wake structure. 

Results show that a transversally inclined cylinder generates more complex flow patterns and creates a high heterogeneity in the flow as well as the depth. The analysis of the dimensionless shedding frequency also suggests the suppression of vortex shedding near both banks when the gap ratio is small. However, vortex shedding characteristics in the central part of the cross-section are similar for the horizontal and inclined cylinders, i.e. the changing gap ratio below the inclined cylinder does not affect significantly the vortex shedding. In the central part of the cross-section, the wake flow is governed by the interaction of the nearly symmetrical shear layers generated above and below the cylinder. Near the banks, the shear layer near the bed or water surface is suppressed, which could explain the suppression of the vortex shedding.
Joint inversion of radiogenic Helium-4 and hydraulic head observations with a neural network surrogate: Application for the Neogene aquifer, Belgium
Authors: Casillas-Trasvina Alberto , Rogiers Bart , Beerten Koen , Wouters Laurent , Walraevens Kristine
Published: March 2022

Environmental tracers are naturally occurring widespread substances in a hydrogeological system that can be used to identify flow pathways, travel times, groundwater age, and recharge rates. However, these are not typically included during the numerical model inversion process. Recent work has broadened their use in a quantitative way by incorporating them in formal solutions of the inverse problem to estimate hydraulic properties and groundwater fluxes. This is commonly done with numerical codes that at least enable one-way coupling of the different processes, i.e., groundwater flow and solute-transport. Helium-4, carbon-14 and temperature-depth profile measurements represent a valuable source of information which can be exploited to support performance assessment studies. For the Neogene aquifer in Flanders, groundwater flow and solute transport models have been developed in the framework of safety and feasibility studies for the underlying Boom Clay Formation as potential host for geological disposal of radioactive waste. However, the simulated fluxes by these models are still subject to large uncertainties, as they are typically constrained by hydraulic heads only. While the evaluation of candidate host formations continues, the use of age tracers (e.g. 4He) as additional (unconventional) state variable for inverse conditioning is being explored. Current methodological developments to integrate such additional unconventional observations will allow i) to test our current understanding and corresponding models of the system, and ii) to potentially decrease the uncertainties associated with model outcomes by a joint inversion approach. From previous campaigns, a total of 18 4Herad observations have been collected at selected sites across the Nete catchment. Furthermore, the accumulation of 4Herad by in situ production and crustal flux is included in the inversion of the 4He-transport model, where the uncertainty of groundwater flow and transport model parameters is evaluated. Additionally, a Latin hypercube sampling (LHS) design is done with parameters drawn from prior distributions. The corresponding simulation results are used to construct a neural network surrogate model  to be used for uncertainty quantification using Bayesian inference. Here, we will present the first results and interpretations of Helium-4 as potential additional state variable for inverse conditioning, and constraining groundwater flow and solute transport models at the catchment scale.
Slow-Mode-Driven Alfvén/Ion-Cyclotron (A/IC) and Fast-Magnetosonic/Whistler (FM/W) Instabilities in the Presence of an Alpha-Particle Beam in the Solar Wind
Authors: Zhu Xingyu , Verscharen Daniel , He Jiansen , Owen Christopher J.
Published: March 2022

In the solar wind, the differential flow between the alpha particles and the protons is an important source of free energy for driving A/IC waves and FM/W waves unstable. Large-scale slow-mode waves can modulate the differential flow, leading to non-negligible locally time-dependent changes in the drift velocity.

We investigate the behaviour of the maximum differential flow with multi-fluid wave theory in the parameter range 0<Uα/VA,p<1.5 and 0.1<βp<10 assuming quasi-perpendicular propagation of the slow mode wave, where Uα is the background alpha particle beam speed, VA,p is the proton Alfvén velocity, and βp is the ratio of the thermal proton energy to the magnetic field energy. We derive an analytical expression for the fluctuation in differential flow, the result of which we confirm through numerical evaluation of the multi-fluid wave equation. The thresholds in terms of Uα/VA,p for the instability of the A/IC and FM/W instabilities in the presence of slow mode waves decrease with increasing slow-mode amplitude and decreasing βp.

We statistically investigate the differential flow between alpha particles and protons based on spacecraft measurements with Solar Orbiter for intervals with clearly identified slow-mode waves as an observational test of our theoretical predictions. We find that slow mode fluctuations play an important role in the driving of A/IC and FM/W instabilities which are important for the energy transfer in the solar wind.
Assessing skill and use of CMIP6 decadal re-forecasts in global glacier mass balance modelling 
Authors: van der Laan Larissa , Förster Kristian , Scaife Adam , Vlug Anouk , Maussion Fabien
Published: March 2022

Within the earth system, glaciers serve as important indicators of climate change, being principally governed by temperature and precipitation. Additionally, they provide essential freshwater storage on various scales, ranging from long-term in firn and ice, to short-term storage in snow cover. By preventing precipitation from immediately turning into runoff, glaciers fulfill a buffering role within their basins, providing downstream runoff during melt season. With changes in glacier mass balance in response to changes in climate, a glacier's buffering capacity is altered simultaneously. In order to predict the evolution of runoff on temporal scales relevant to water resource management (5-15 years), it is essential to observe and simulate glacier mass balance on the same scale. The current research presents a global modelling approach using the Open Global Glacier Model (OGGM), forced with a multi-model, multi-member retrospective ensemble of monthly temperature and precipitation re-forecasts (hindcasts) from the Decadal Climate Prediction Project (DCPP), part of the Coupled Model Intercomparison Project, phase 6 (CMIP6). The decadal hindcasts are initialized each year in the period 1960-2010 and are bias corrected for model drift, while retaining the period's warming trend, using a lead-time based correction. The hindcasts are then downscaled to the glacier scale and used to compute the climatic mass balance with OGGM, with fixed glacier geometries. The method is validated using 274 reference glaciers, which have a >5 year observational record. It is then applied globally, to all land-terminating glaciers in the Randolph Glacier Inventory (RGI), outside the Greenland Ice Sheet and Antarctica. The results indicate merit in using decadal re-forecasts to model glacier mass balance, paving the way for reliable decadal scale runoff predictions on regional and global scales.
Emergence of a sub-ice platelet layer in mushy-layer sea ice model simulations
Authors: Vancoppenolle Martin , Wongpan Pat , Langhorne Pat
Published: March 2022

Sightings have long reported the presence of unconsolidated ice crystals spanning up to several meters in thickness under Antarctic landfast sea ice. This so-called sub-ice platelet layer (SIPL) was until recently considered as exotic and out of the scope of standard sea ice models.

Here we show that a realistic, highly porous and isothermal SIPL emerges in one-dimensional mushy-layer sea ice model simulations, provided appropriate thermal forcing. The model SIPL develops once conductive heat fluxes are insufficient to cause internal freezing of the new, highly porous ice. Sufficiently high snow and ice thicknesses are key to the onset of the SIPL development, whereas high liquid content and isothermal character stabilize the SIPL.

Two model features are necessary to the emergence of the SIPL: an advective formulation of salt dynamics, and a high value for the liquid fraction of new ice. We surmise that large-scale ice-ocean models should capture a SIPL at physically sensible locations and times if the aforementioned issues are properly considered.
Climate change projections for Greece in the 21st century 
Authors: Akritidis Dimitris , Georgoulias Aristeidis K. , Kalisoras Alkiviadis , Kapsomenakis John , Melas Dimitris , Zerefos Christos S. , Zanis Prodromos
Published: March 2022

Here, we present an updated assessment of projected climate change over Greece in the near future and at the end of the 21st century. The analysis is based on an ensemble of 11 high-resolution EURO-CORDEX simulations based on historical emission data and three different greenhouse gas concentration scenarios, namely, RCP2.6, RCP4.5, and RCP8.5. Our results strongly point towards a warmer future under all the examined RCPs. Under the extreme RCP8.5 scenario, temperature is expected to increase on average by 1.6 oC (12%) in the near future and 4.3 oC (33%) at the end of the century. The number of hot days and tropical nights per year is expected to increase significantly and the number of frost days to decrease. Also, the future will be possibly drier, with statistically robust results for the end-of-the-century period under RCP8.5 only. On average, precipitation is  expected to decrease under RCP8.5 by -0.4 mm day-1 (-16%) and the number of consecutive dry days per year to increase by 15.4 days (30%) at the end of the century.

The authors acknowledge funding from the Action titled "National Νetwork on Climate Change and its Impacts - CLIMPACT" which is implemented under the sub-project 3 of the project "Infrastructure of national research networks in the fields of Precision Medicine, Quantum Technology and Climate Change", funded by the Public Investment Program of Greece, General Secretary of Research and Technology/Ministry of Development and Investments.

 
Spatial and temporal variation of magmatism in the East African Rift System: influence of tectonics and different mantle domains
Authors: Braschi Eleonora , Tommasini Simone , Corti Giacomo , Orlando Andrea
Published: March 2022

The East African Rift System (EARS) is the classic example of an active continental rift associated with extension, deformation, lithosphere thinning, and generation of magmas from different mantle domains and depths. Magmatism and tectonics have always been closely linked and their mutual relationships concern many processes such as the kinematics and rates of extension, the passive versus active role of mantle upwelling and magma genesis. In addition, the spatial and temporal variations of the geochemical signature of magmas varies in response to different mantle domains contributing to their genesis (subcontinental lithosphere, asthenosphere and deeper mantle sources).

In this study we carefully screened an exhaustive geochemical database of basalts (including authors’ unpublished data) emplaced in the EARS to decipher the possible connection between different mantle domains, and the evolution and tectonic characteristics of the EARS. The geochemical data were subdivided according to spatial and temporal criteria: from a spatial point of view, the samples were ascribed to five groups, namely Afar, Ethiopia, Turkana depression, Kenya and Tanzania. From a temporal point of view, the magmatic activity of the EARS was subdivided into three main temporal sequences: 45-25 Ma, 25-10 Ma and 10-0 Ma.

The geochemical signature and radiogenic isotopes (Sr, Nd, Pb) of the selected basalts reveal significant spatial and temporal variations and permits to place important constraints on the contribution of subcontinental lithosphere, asthenosphere, and lower mantle in magma genesis
Pollen-based Holocene temperature and precipitation pattern of the Northern Hemisphere regions in the light of the global temperature trend
Authors: Herzschuh Ulrike , Boehmer Thomas , Li Chenzhi , Cao Xianyong , Chevalier Manuel , Dallmeyer Anne
Published: March 2022

Mismatch in model- and proxy-based Holocene climate change, known as the Holocene Conundrum, may partially originate from the poor spatial coverage of climate reconstructions e.g. in Asia, limiting the number of grid cells for model-data comparison. Here we investigate pollen-based reconstructions of mean annual, mean July temperature, and annual precipitation from 2594 sites in  the northern hemisphere extratropics that were set up with a harmonized calibration method and were presented with revised chronologies. Temperature trends show strong latitudinal pattern and differ between (sub-)continents. While Europe and eastern North America show a pronounced mid-Holocene temperature maximum, western North America shows only weak changes and Asia a continuous Holocene temperature increase but with strong latitudinal differences. While on hemisphere scale, temperature and precipitation show similar trends (i.e. a Holocene toward the late mid-Holocene increase until followed by a slight decline until present), on continental and regional scale positive, negative and non-correlation are found. Particularly in Asia strong latitudinal pattern of precipitation is found.  Finally, we merged our data with the data of Kaufman et al 2020 doubling the number of records in this data base and presented a revised global temperature curve.
Applying PIV algorithms to understand the dynamic behaviour of tidal compound dunes
Authors: Scheiber Leon , Wu Kuan-Ying , Lojek Oliver , Visscher Jan , Schlurmann Torsten
Published: March 2022

Particle Image Velocimetry (PIV) is an optical method typically applied to measure two- and three-dimensional fluid flows. In combination with a synchronized laser or strobe light, a high-resolution camera is used to observe the movement of tracer particles within a water volume. Advancing the concept of cross-correlation, modern PIV algorithms analyze the obtained images for most probable displacements in pre-defined interrogation areas and, in doing so, are able to reveal detailed flow patterns and velocities. Although this methodology is widely applied to study turbulent flows and even track grain-scale sediment transport, hardly any investigation is known that makes use of one of the more sophisticated PIV tools to quantify the dynamics of major geomorphological features such as subaqueous dunes.

In order to test its applicability in morphodynamic analyses, we used a prominent PIV software for interpreting a long-term bathymetric time series recorded by multibeam echo-sounding (MBES). The data set shows a field of compound dunes in the Jade tidal inlet channel well-documented in 100 monthly fairway surveys. In contrast to conventional PIV settings, observed displacements in the assessed greyscale surface plots do not represent the movement of individual particles but migration of complete morphological features across the seafloor. Accordingly, this methodology results in a reduction of correlation clarity, which we compensated by two types of pre-processing. On the one hand, PIV analyses were conducted for the different derivatives of the digital terrain model comprising slope, curvature and variability. On the other hand, reports about the physical composition of primary and secondary dunes were used to separate the inherent length scales, which are expected to show different migration rates. Depending on these filtering techniques, preliminary results are in promising agreement with previous findings, thus, illustrating the versatility of the PIV concept and its potential for two-dimensional morphodynamic analyses. Based on a systematic comparison of the achieved correlation qualities, we now aim at deriving best practices for applying PIV algorithms to understand the dynamic behaviour of tidal compound dunes.
Ecosystem services, monetary value and social sphere: a specific-vegetation software suite on a urban-scale project
Authors: Busca Francesco , Revelli Roberto
Published: March 2022

The concept of ecosystem services (ES), as a set of components of the natural capital that provide products and services directed to humans, was born around the middle of the last century, reaching a more systematic definition in the early 2000s with the Millennium Ecosystem Assessment (MA, 2005). This issue is implicitly linked to popular research topics, such as climate change,  population well-being, fight against hunger in the world and has undergone a significant increasing interest from scientific research since the SDGs subscription, defined in the 2030 Agenda.

With the thrust of the investigation into this new branch, various tools have been created aimed at dealing with ecosystem services, not only from a qualitative point of view but in quantitative terms. The present work aims to analyze the applicability of a specific SE quantification software for vegetation, based both on the use of meteorological data and on the acquisition of field data and capable of returning outputs relating to the main components: environment (air quality), soil (use and cover) and water (quality and quantity of water runoff, with a focus on vegetation hydrology). The combination of this eco-hydrological model with a monetary ES evaluation is also interesting: although the economic model considered is particularly simple and therefore characterized by a non-negligible standard error, it is important to underline the direct and spontaneous association between SE and monetary quantification considered by the software, unlike how at the end of the last century the economic value of nature was still neglected.

Finally, the main results of a ES quantification project in an Italian urban context will be discussed, underlining  the environmental improvement to the surroundings and the social benefits for the population.
Seismicity of the Terceira Island (Azores) recorded by a temporary seismic network  
Authors: Fontiela João , Afonso Dias Nuno , Silveira Graça , Moreira Mário , Carrilho Fernando , Matias Luís
Published: March 2022

The last eruption in the Azores archipelago occurred in 1998-2000 and took place offshore, broadly 10 km WNW of Terceira. Terceira Island comprises four central polygenetic active volcanoes, Santa Bárbara, Pico Alto, Cinco Picos-Serra do Cume, Caldeira Guilherme Moniz, and a Basaltic Fissural zone. 

To study the seismicity at Terceira Island, we installed a dense seismic network with an average inter-station distance of 5 km. The total number of instruments in use were 31: 12 short-period (2 Hz) and five very short periods (4.5 Hz), both from Institute Dom Luiz (IDL), eight broadband (30s) from the University of Evora (UEv). The very short period instruments were installed around the Pico Alto geothermal power plant to improve the detectability of the micro-seismicity of the zone. The temporary seismic network operated at full capacity for 11 months and later with instruments from UEv and IPMA until the end of 2020. The permanent stations operated by the Instituto Português do Mar e da Atmosfera (IPMA), namely two broadband (120s), two short period (5s) and two accelerometers, completed the temporary network. 

This work presents the preliminary results obtained with the seismic network. We detected some volcano-tectonic earthquakes in this period, mostly related to the Santa Bárbara Volcano and calculated the focal mechanism to the most energetic events. Behind the regular seismicity around the island, we observe an abnormal number of earthquakes in the stations installed in Pico Alto and central part regions.

Acknowledgments: This work is co-funded by national funds through FCT - Fundação para a Ciência e a Tecnologia, I.P., under projects Ref UIDB/04683/2020, UIDB/50019/2020 e UIDP/04683/2020
A rare record of late Neogene glaciation from the north east Greenland margin
Authors: Knutz Paul , Nielsen Tove , Sliwinska Kasia , Fyhn Michael , Hopper John , Jennings Anne , Bierman Paul , Christ Andrew , Corbett Lee , Hidy Alan
Published: March 2022

Studies based on deep ocean drilling cores points to North-East Greenland as a focal point for ice sheet accumulation incurring much earlier than the Pleistocene Northern Hemisphere glaciation. The build-up of marine-based ice sheets in these parts is critical to the cooling of the Nordic Seas and the Arctic Ocean, considered as a pre-condition for the modern ocean “conveyor belt” circulation. However, proximal sedimentary records that can shed light on the timing and climate background of early Greenland Ice Sheet evolution are lacking. In 2008 a series of shallow cores were drilled by the Kanumas consortium on the NorthEast Greenland shelf and Cenozoic sediments were recovered at several sites. Here we present litho- and palynostratigraphic information, along with new cosmogenic isotope results, of a 110 m long sediment core (Kanumas 13). The core study, supported by regional seismic data, suggests that ice streams may have been active on the North-East Greenland margin since middle-late Miocene. Geochemistry and magnetic susceptibility data indicate that an abrupt change in sediment source occurred at 50.8 m. The shift in provenance is accompanied by a transition to more open marine conditions. The implications for the Greenland Ice Sheet and Artic climate development will be addressed in the presentation.
Disequilibrium clumped isotope values in glendonites support formation linked to rapid CO2 degassing and methane seepage
Authors: Koenders Emily , Kaskes Pim , de Winter Niels , Jochmann Malte , van de Schootbrugge Bas , Ziegler Martin
Published: March 2022

Glendonites are calcite pseudomorphs, that form after the mineral ikaite. Their occurrence in sediments is typically seen as an indication of cold environmental conditions, even when found in predetermined greenhouse climates (Zhou et al., 2015). However, there is still uncertainty about the exact conditions that control glendonite formation and their occurrences are often in conflict with other temperature proxies (Price et al., 2013). Some authors have postulated that the temperature stability range of ikaite could be extended under certain chemical boundary conditions (Teichert and Luppold, 2013). One process that could possibly lead to such circumstances is methane seepage. Here we use clumped isotope thermometry to determine the formation temperature of glendonites. The analysed specimen, comes from a mud volcano, within the upper Paleocene, Basilika Formation near Sveagruva in Svalbard.

Thin section analyses and micro-X-ray fluorescence mapping of a glendonite specimen, show that the mineral is highly heterogeneous in terms of trace elemental incorporation. We sampled two distinct phases, for isotope analysis. The clumped isotope composition for both phases are relatively low, indicating apparent formation temperatures >50 degrees, which  are unrealistic values for the formation temperature of ikaite. The high Sulfur concentrations, surrounding sediments and low δ13C values of the glendonite are consistent with a formation and decomposition of the ikaite/glendonite caused by the activity of a methane seep. Degassing of CO2 coupled to the methane seepage may have caused isotopic disequilibrium resulting in low clumped isotope values (Bajnai et al., 2020).

Sources

Bajnai, D., et al., 2020.: ‘Dual clumped isotope thermometry resolves kinetic biases in carbonate formation temperatures’, Nat Commun, 11, 4005, https://doi.org/10.1038/s41467-020-17501-0.

Price, G., et al., 2013. Isotopic evidence for long term warmth in the Mesozoic. Sci. Rep. 3 https://doi.org/10.1038/srep01438.

Teichert, B. M. A., et al., 2013. ‘Glendonites from an Early Jurassic Methane Seep — Climate or Methane Indicators?’ Palaeogeography, Palaeoclimatology, Palaeoecology, 390, 81–93. https://doi.org/10.1016/j.palaeo.2013.03.001.

Zhou, Xiaoli, e.a, 2015. ‘Ikaite Abundance Controlled by Porewater Phosphorus Level: Potential Links to Dust and Productivity’. The Journal of Geology, 123, 3, 269–81. https://doi.org/10.1086/681918.
Importance of land-cover data-set spatio-temporal resolution on water budget modeling in highly irrigated areas, Telangana, India
Authors: Paswan Abhilash Kumar , Ferrant Sylvain , Selles Adrien , Tiwari Virendra Mani , Ahmed Shakeel
Published: March 2022

Falling water tables in several parts of India, especially in the southern part, experiencing semi-arid climatic conditions with hard rock aquifer systems, possess a threat to food, water and economic security to millions of citizens. Understanding of the water budget in such an area is paramount to take necessary steps towards planning of water usage and its management. Land use information at 1km is recognized as sufficient in hydrological modeling. But what is the best resolution of land use forcing variables for agro-hydrological modeling to simulate the water budget by taking agricultural water withdrawal into account. This study focuses on the use of medium (500m) and high resolution (10m) land cover maps derived from satellite products to map the seasonal rice inundated area extent in the Telangana state to estimate the Irrigation Water Demand (IWD) and withdrawal. We employed Soil and Water Assessment Tool (SWAT), a process based ecohydrological river basin or watershed model, to assess how resolution of land use maps may affect the water budget representation of Telangana. The model is calibrated and validated for a period from 2015 to 2020 (6 years) using monthly river runoff data, groundwater and terrestrial water fluctuation derived from respectively governmental piezometric observations (TSGWD) and GRACE. An uncertainty analysis was performed using the Sequential Uncertainty Fitting (SUFI-2) algorithm. Preliminary results suggest that though trends in runoff are influenced by climate drivers, as southwest monsoon contributes appx. 80% of annual rainfall. However, the farmers seasonal land cover adaptation to surface and groundwater availability have a strong impact on water balance over the study area. Precise land cover information of such temporal variations based on appropriate spatial resolution satellite observations contributes to accurate estimate of IWD especially in groundwater fed areas where rice areas are spread in small aggregates. This study also highlights the adaptation and importance of temporal and spatial resolution of datasets in strategic planning and water management practices in water stressed regions. 
Monitoring slope instability integrating InSAR, GNSS, Total Station and Levelling: a case study in the Eastern slope of the Mt. Amiata volcanic complex, Italy
Authors: Pattela Taraka Venkatadripathi , Disperati Leonardo , Marzini Lorenzo , Amaddii Michele , Lombardi Gianni , Rappuoli Daniele
Published: March 2022

Landslides are considered one of the major hazards causing economic and human losses worldwide. Slope instability processes are affecting buildings and infrastructures in the towns of the eastern slope of the Mt. Amiata volcanic complex (Tuscany, Italy). These processes are relevant as they expose the inhabitants to risk, moreover their analysis provide hints about the mechanisms and roles of land sliding in the progressive disruption of extinct volcanic edifices.

In this study we present the first results of some monitoring and multi-temporal systems which are integrated to investigate the spatial-temporal ground displacement field in the eastern slope of the Mt. Amiata volcanic complex. In detail, we combine InSAR, GNSS, robotic total stations (TS) and levelling techniques to obtain a framework in terms of planimetric and vertical displacements. We apply the Multi-Temporal InSAR approach from 2014 to 2021 using the ESA Copernicus Sentinel-1 data. To perform the interferometry analysis, we implement the single master Stanford Method for Persistent Scatterers (StaMPS) approach for both ascending and descending geometries, and by combining both Line of Sight (LOS) results, we reveal the vertical and E-W components of the displacement. In addition, we perform multi-temporal survey-style GNSS measurements for some tens stations from 2019 to present day. About one hundred reflectors are continuously monitored by TS. Additionally, multi-temporal geometric levelling is performed to assess the vertical movements of selected relevant benchmarks. Finally, results from different monitoring systems are combined to model the ground displacements.

The InSAR results reveal mean velocity vectors with standard deviation less than 1 mm/y. The GNSS results have higher signal to noise ratio in the horizontal components with residuals lower than 10 mm. Accuracies of the geometrical levelling and TS results are ca. 1 mm and ca. 5 mm respectively. By combining the results, the magnitude of displacement field is ranging up to ca. 30 cm/y. The different systems provide results each other reasonably coherent in terms of magnitude and direction of the displacement vector. Integration of systems allows us to get solutions where one or more systems fail to provide data (i.e., when few or no PS are obtained by InSAR). Finally, we compare the results with seasonal data like rainfall. Velocities tend to reduce during summer low precipitation periods, while they increase during winter. Long term quantitative monitoring activities will allow us to better understand the spatial-temporal evolution of the landslide processes in the perspective of developing an early warning system.
A Novel Cellulose Acetate Fouling-Resistant Ultrafiltration Membranes for Heavy Metal Remediation
Authors: Ursino Claudia , Santoro Sergio , Ounifi Ibtissem , Hafiane Amor , Figoli Alberto
Published: March 2022

Water contamination by traces of heavy metals is a global issue causing serious environmental and health concerns and, as a consequence, an increasing of demand for water remediation technologies. Nowadays, membranes, defined as a selective barrier that permit the separation of molecules or ions in a liquid by a combination of sieving and diffusion mechanisms, have more attention due to their several advantages. In particular, ultrafiltration (UF) is a well-established membrane technology for purification of contaminated water bodies enabling an efficient and cost-saving low-pressure filtration. However, UF membranes possesses a pore size ranging from 20 nm to 0.1 µm, ineffective in rejecting small molecules and ions, such as heavy metals. In this work, a new generation of antifouling UF membranes able to heavy metals remediation has been developed [1]. Specifically, poly (acrylic acid) (PAA) as ideal complexing agent for heavy metals, was blended with cellulose acetate (CA), polymer extensively studied in UF membranes preparation. The novel membranes were prepared via non solvent-induced phase separation (NIPS). These new membranes combine the use of carboxyl group of the PAA that allowing one to efficiently adsorb or chelate heavy metal ions with the processability/biocompatibility/hydrophilicity of the CA. The membranes were produced varying the PAA concentration from 0 to 15wt. %. The homogeneity of the blend was evaluated via differential scanning calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR). Mitigation of the fouling phenomena and the improvement of the efficiency of the CA membrane on heavy metal rejection was studied and evaluated. The experiments results revealed the important advantages of the blend, since CA/PAA membranes showed superior performance with respect to the neat CA membrane, in terms of: (i) water permeability (20% higher than the neat CA membrane); (ii) Cd rejection (83% at pH 6.5); and (iii) antifouling resistance to humic acid (HA) (R% of 99.9 and 95.3% of flux recovery ratio FRR).

 

[1] I. Ounifi, Y. Guesmi, C. Ursino, S. Santoro, S. Mahfoudhi, A. Figoli, E. Ferjanie, A. Hafiane, Antifouling Membranes Based on Cellulose Acetate (CA) Blended with Poly(acrylic acid) for Heavy Metal Remediation, Appl. Sci. 2021, 11, 4354. https://doi.org/10.3390/app11104354
Kinetic turbulence generated by accelerated particles in a reconnecting current sheet with magnetic islands
Authors: Zharkova Valentina , Xia Qian
Published: March 2022

The kinetic turbulence generated by accelerated particles in a reconnecting current sheet (RCS) with X- and O-nullpoints is considered. The simulations of magnetic reconnection using particle-in-cell (PIC) approach is carried out in a thin current sheet with 3D magnetic field topology affected by tearing instability that leads to a formation of two large magnetic islands . The model utilises a strong guiding field that leads to separation of the particles of opposite charges, generation of a strong polarisation electric field across the RCS and suppression of kink instability in the ’out-of-plane’ direction. The accelerated particles of the same charge entering an RCS from the opposite edges are shown accelerated to different energies forming the ‘bump-in-tail’ velocity distributions that, in turn, can generates plasma turbulence in different locations. The turbulence produced by either electron or proton beams is identified from the energy spectra of electromagnetic field fluctuations in the phase and frequency domains.

The spectral index of the power spectrum In a wavenumber space of the turbulent magnetic field near the ion inertial length approaches -2.7. The collective turbulence power spectra are consistent with the high-frequency fluctuations of perpendicular electric field, or upper hybrid waves, to occur in a vicinity of X-nullpoints, with the Langmuir waves  generated by accelerated electrons which can be converted to  Bernstein waves when electron beams become moving across the magnetic field lines. The frequency spectra of high and low-frequency waves are explored in the kinetic turbulence in parallel and perpendicular directions to the local magnetic field showing noticeable lower hybrid turbulence. The implication of finding for observations is also discussed.
Turbulent dissipation in weakly-collisional plasmas
Authors: Pezzi Oreste
Published: March 2022

Understanding the dissipation of energy and the associated heating in weakly collisional turbulent plasmas represents still an unresolved challenge. Here we examine an ensemble of parameters commonly adopted to characterize processes of energy dissipation and conversion in plasmas by means of hybrid Vlasov-Maxwell simulations describing plasma turbulence at sub-proton scales in the whole six-dimensional phase-space.

We make a distinction between ``energy-based'' and ``distribution-function'' based parameters. The first class is related to energy transfer mechanisms, while the second one requires exact knowledge of the particle distribution function in velocity space. All these measures highlight that energy dissipation occurs inhomogeneously and close to regions that are characterized by intense magnetic stresses. The dependence of these processes with respect to the proton β parameter is finally explored. 
Tight coupling between photosynthesis and soil carbon turnover indicative of rhizosphere priming in the field
Authors: McCloskey Chris , Kirk Guy , Otten Wilfred , Paterson Eric
Published: March 2022

While rhizosphere priming effects are well-documented under laboratory and controlled-environment conditions, their significance in undisturbed systems under field conditions is less clear. This is in part because it is impracticable to measure rates of rhizodeposition in the field with high resolution over a substantial period. We propose that photosynthesis, closely linked to rhizodeposition, can be used as a proxy for plant root activity.

We have used a field system containing 24 0.8-m diameter, 1-m deep lysimeters holding naturally-structured soil monoliths from two contrasting C3 soils sown with a C4 grass (Bouteloua dactyloides) to measure carbon (C) fluxes at a high temporal resolution, exploiting isotopic differences to allow partitioning of plant and soil fluxes. These fluxes are coupled to high-resolution measurements of soil temperature and moisture, alongside atmospheric temperature and solar radiation. This system has allowed measurement of both ecosystem resolution and net ecosystem exchange, and the partitioning of respiration between plant and soil sources using stable isotope methods. Using this system we have generated a dataset of measured and modelled respiration and photosynthesis fluxes over two years.

Our dataset has revealed clear seasonal and diurnal patterns in plant and soil fluxes. We have assessed the relationship between diurnal patterns in soil respiration and potential drivers, and examined whether model estimates of soil respiration are improved by the inclusion of photosynthesis as an explanatory variable alongside soil moisture and temperature. We found a significant positive relationship between photosynthesis and soil respiration, and inclusion of photosynthesis improves models of soil respiration. This is best explained by rhizosphere priming enhancing soil C turnover.
Terrain Change Detection with ICESat-2: A Case Study of Central Mountain Range in Taiwan
Authors: Pan Pin-Chieh , Tseng Kuo-Hsin
Published: March 2022

Ice, Cloud, and land Elevation Satellite 2 (ICESat-2), part of NASA's Earth Observing System, is a satellite mission for measuring ice sheet elevation as well as land topography. ICESat-2 is equipped with the Advanced Topographic Laser Altimeter System (ATLAS), a spaceborne lidar that provides topography measurements of land surfaces around the globe. This study intends to utilize ICESat-2 ATL03 elevation data to identify the outdated part in Taiwan’s Digital Elevation Model (DEM). Because the update of DEM takes time and is relatively expensive to renew by airborne LiDAR, a screen of elevation change is crucial for planning the flight route. ICESat-2 has not only a dense point cloud of elevation but also a short revisit time for data collection. That is, ICESat-2 may have a chance to provide a reference for the current condition of terrain formation.

In this study, we aim to verify the 20-meter DEM from the Ministry of the Interior, Taiwan, by ICESat-2 elevation data. The goal is to find out the patches that have experienced significant changes in elevation due primarily to landslides. We select a typical landslide hillside in southern Taiwan as an example, and compare the DEM with ICESat-2 ATL03 photon-based heights before and after the occurrence of landslide events. In our preliminary results, the comparison of DEM and ICESat-2 ATL03 heights has a high degree of conformity inaccuracy (within meter level), indicating ICESat-2’s ability for DEM renewal.
Fault opening on thrust faults due to free surface interaction and its near-field deformation features
Authors: Villafuerte Carlos , Bhat Harsha S. , Okubo Kurama , Rougier Esteban , Dubernet Pierpaolo
Published: March 2022

Thrust faults are commonly known to produce significant amounts of slip, damage and ground acceleration, especially close to the free surface. The effect of the free surface on faulting has always been a standing issue in theoretical mechanics. While static solutions exist, they still cannot explain the large amounts of slip, damage and ground acceleration observed on low dipping faults. Dynamics effects raised by the presence of a free surface were first evaluated by Brune [1996] using analog experiments, which hinted at a torque mechanism induced in the hanging wall leading to a natural reduction in elastic compressive normal stress as the rupture approaches the surface. This solution was recently supported by preliminary work from Gabuchian et al. [2017], which, combining numerical and experimental simulations, also showed that the earthquake rupture, propagating up dip, induces rotation of the hanging wall, and might promote fault opening.

In this work, we use enhanced numerical solutions for earthquake rupture, based on the Combined Finite-Discrete Element Methodology (FDEM), which were recently developed by the Los Alamos National Laboratory, to carry out dynamic rupture simulations on thrust faults to characterize this opening effect and investigate the physical mechanism responsible for it. Through a systematic analysis of case studies, we explore the effect of fault geometry and friction properties on rupture behavior and its associated deformation pattern. We observe that fault opening occurs in all our simulations and increases significantly as the rupture reaches the free surface and for low dip-angle faults.We document the evolution of different metrics such as slip, slip rate, fault-normal displacement and velocities, as well as the displacements and velocities on the free surface to identify near-field deformation features that will serve as synthetic data when comparing with recorded surface deformation from real-case earthquakes.
Dynamic Rainfall Thresholds for Landslide Early Warning System in Progo Catchment, Java, Indonesia
Authors: Satyaningsih Ratna , Jetten Victor , Ettema Janneke , Sopaheluwakan Ardhasena , Eko Nuryanto Danang , Umer Yakob , Astuti Nuraini Tri , Anggraeni Rian
Published: March 2022

Landslide occurrences are governed by precondition factors and triggering factors. Hence, it is desirable to include physical parameters representing precondition factors in determining thresholds over which landslides are likely to occur. In the case of rainfall-triggered landslides, such parameters include soil properties and land cover information. However, high-resolution data required for a physical-based approach are rarely readily available for a large area, especially in developed countries. Therefore, in developing a landslide early warning system (LEWS) for a large area, rainfall thresholds are derived by optimizing the usage of rainfall datasets.

This study aims to derive rainfall thresholds from a meteorological perspective regarding rainfall event characteristics (e.g., cumulative rainfall, intensity, duration) that result in trigger the landslides in Progo Catchment in Java, Indonesia.  We explore various hourly rainfall datasets, including rain gauge measurements and satellite-based rainfall products (e.g., the Japan Aerospace Exploration Agency’s Global Satellite Mapping of Precipitation/GSMaP and the Climate Prediction Center/National Oceanic and Atmospheric Administration’s morphing technique/ CMORPH), to derive the thresholds. The effect of rainfall event characteristics is assessed by clustering the rainfall event types and preceding conditions associated with different triggering mechanisms leading to the landslide occurrences. The rainfall thresholds are then derived using the frequentist method for each group, hence “dynamic.” 
Impact of linear infrastructure on floodplains on inundation characteristics
Authors: Krylenko Inna , Belikov Vitaly , Golovlyov Pavel , Surkov Vitaly , Zakharova Elena , Zavadskii Alexander
Published: March 2022

Linear infrastructure such as roads, bridge crossings, protective dams cause significant changes of the floodplains topography and flow characteristics. To estimate the anthropogenic impact on the changing of inundation characteristics we applied two-dimensional hydrodynamic modeling approach. The study is focused on wide populated floodplains areas of the Ob River near Surgut city (Western Siberia, Russia), Lena River near Yakutsk city (Eastern Siberia), Amur/Zeya Rivers near Blagoveshchensk (Far East). STREAM_2D software (authors V. Belikov et al.), which is based on the numerical solution of two-dimensional Saint-Venant equations on a hybrid curvilinear quadrangular and rectangular mesh, and includes sediment transport and ice modules, was used for the simulations. Detailed topography and bathymetry data, obtained as results of field surveys, were used for model setup. All linear infrastructure in river channels and floodplains, including dams, cities embankments, existing and under construction bridges, road embankments were taken into account in the model grid and relief. Second version of the model relief was constructed excluding infrastructure. Calibration and verification of the model were performed for modern conditions using data of field surveys and data of gauging stations. Additional verification of simulated flooded areas and the water level in ungauged reaches was done using high resolution satellite optical images and satellite altimetry measurements. For impact analysys two modeling scenarios were considered for each key area: modern conditions of flow with all infrastructure and natural conditions without any constructions. More pronounced effect of the infrastructure on the flooding zones was identified for the floodplains of Amur/Zeya Rivers near Blagoveshchensk and Heihe cities: the area of flooding in modern conditions decreased by 10%, which led to an increase in the average depth of flooding by 10%, and the average flow velocity in the modeling area by 2-5%. Significant backwater effects due to linear infrastructure on the floodplains were identified for the Ob River, water levels upstream the existing bridge transect can rise more than 0.5m and observed at a distance of more than 30 km.

The numerical experiments were designed within the framework of the Governmental Order to Water Problems Institute, Russian Academy of Sciences, subject no FMWZ-2022-0001. The Ob River floodplain model was adopted with the financial support of RSF № 22-27-00633.