bluuebunny/crossref_metadata_2025 huggingface dataset:
Sentinel-1 InSAR Time-series Monitoring of the Unstable Rock Slopes in North Sikkim, India
Authors: Aslan Gökhan , Dehls John , Hermanns Reginald , Penna Ivanna , Sengupta Aniruddha , Gupta Vikram
Published: March 2022

The trans-Himalayan highway, between Gangtok and Yumthang, winds along steep valley sides, including a long section above the Teesta River. Many villages are precariously perched above the V-shaped valley bottoms. The highway is subject to frequent rainfall-triggered landslide events during monsoon season, disrupting transport and destroying infrastructure. The area has also experienced at least three large rock slope failures (RSF) within the past 40 years and many smaller RSF after the 2011 Sikkim earthquake (Martha et al, 2015). Earlier RSF, many prehistoric, have left at least 30 large boulder deposits along the valley. Several of those such as the Lanta Khola landslide get reactivated each monsoon season (Sengupta et al., 2011). A number of villages are located on these deposits, as they are frequently found in shallower sections of the valley slopes.

In the present study, Persistent Scatterer InSAR (PSI) has been employed, using Sentinel-1A and -1B Synthetic Aperture Radar (SAR) images acquired between 2015 and 2021 for selected historical landslides and landslide-prone areas along the Dzongu and Yumthang Valleys. Among them are the massive translational Dzongu landslide that occurred in 2016 near Mantam village forming a landslide dam (Morken et al., 2020), a large rock avalanche that occurred in 2015 in Yumthang valley (Penna et al., 2021), and several slope instabilities in the cities of Mangan and Mangshila.

Despite the challenges of dense vegetation and winter snow, we detected sufficient targets within the landslides, mainly over the scar areas, rock outcrops, building roofs, and landslide deposits. In this study, we compare the movement/settlement of these historic deposits with ongoing movement in prehistoric deposits. We look at linear vs seasonal components of ongoing deformation within the settlements built upon RSF deposits and discuss the implications with respect to possible catastrophic reactivation.

 

Martha, T. R., Govindharaj, K. B., & Kumar, K. V. (2015). Damage and geological assessment of the 18 September 2011 Mw 6.9 earthquake in Sikkim, India using very high-resolution satellite data. Geoscience Frontiers, 6(6), 793-805.

Morken, O. A., Hermanns, R. L., Penna, I., Dehls, J. F., & Bhasin, R. (2020, June). The Dzongu landslide dam: high sedimentation rate contributing to dam stability. In ISRM International Symposium-EUROCK 2020. OnePetro.

Penna, I. M., Hermanns, R. L., Nicolet, P., Morken, O. A., Dehls, J., Gupta, V., & Jaboyedoff, M. (2021). Airblasts caused by large slope collapses. Bulletin, 133(5-6), 939-948.

Sengupta, A., Gupta, S., and Anbarasu, K., 2010, Rainfall thresholds for the initiation of landslide at Lanta Khola in north Sikkim, India: Natural Hazards, v. 52, no. 1, p. 31-42.
Reflection seismic investigation of a subrosion area using a combined approach of P- and SH-waves
Authors: Wadas Sonja , Buness Hermann , Rochlitz Raphael , Günther Thomas , Skiba Peter , Grinat Michael , Polom Ulrich , Tanner David , Krawczyk Charlotte
Published: March 2022

Subrosion, the dissolution of soluble rocks, e.g., sulfate, salt, or carbonate, and the resulting structures, such as sinkholes and depressions, are a great geohazard because they can cause damage to buildings and infrastructure, and lead to life-threatening situations. The process requires unsaturated water and fluid pathways that enable the water to flow through the subsurface and generate cavities.

In Germany, sinkholes are a widespread problem, because soluble rocks, such as gypsum and anhydrite, are located close to the surface in many areas. One such area is the federal state of Thuringia, where our study area Bad Frankenhausen is situated.

For a better understanding of the local subrosion processes and structures, a detailed subsurface characterization of sinkholes and small- and large-scale depressions was necessary. Therefore, we used P-wave and SH-wave reflection seismics for high-resolution imaging of the near-surface. We were able to identify covered subrosion structures and –zones, and faults and fractures, which serve as fluid pathways. The seismic investigations were supplemented by geoelectric and gravimetric surveys in order to validate the interpreted fluid pathways and areas of underground mass movement.

We conclude that tectonic movements during the Tertiary, which lead to the uplift of the Kyffhäuser hills north of Bad Frankenhausen and the formation of faults parallel and perpendicular to the low mountain range, were the initial trigger for subrosion. The faults and the fractured Triassic and Lower Tertiary deposits serve as fluid pathways for groundwater to leach the deep Permian Zechstein deposits, and subrosion is more intense near faults. The artesian-confined salt water ascends towards the surface along the faults and fracture networks, which formed an inland salt marsh over time. In the past, subrosion of the soluble Zechstein Formations formed several, now covered, sagging and collapse structures, and, since the entire region is affected by recent sinkhole development subrosion must be still ongoing.

Due to the results of this study, we suggest a combined approach using P- and SH-wave reflection seismics to identify and analyse subrosion structures, and to use additional geophysical methods like electromagnetic- and gravimetric surveys to develop a more comprehensive model explaining the local subrosion processes.
The ATom, A-LIFE, and FIREX-AQ data set: automatic cloud detection and properties of aerosol-impacted cirrus
Authors: Dollner Maximilian , Gasteiger Josef , Schöberl Manuel , Gattringer Andreas , Beres Nicholas D. , Diskin Glenn , Bui T. Paul , Weinzierl Bernadett
Published: March 2022

Clouds remain one of the largest uncertainties connected to future climate predictions, due partly to existing gaps in the understanding of cloud microphysical processes. Airborne in situ observations provide relevant data sets to investigate these cloud microphysical processes. However, the process of selecting and classifying cloud sequences can be very time consuming if done manually and algorithms developed by the community are numerous and prone to misclassification, particularly when coarse aerosol is present.

We developed a novel cloud indicating algorithm, automatically detecting and classifying clouds in airborne in situ observations, based on data of three international airborne field campaigns, including ATom (Atmospheric Tomography; 2016-2018), A-LIFE (Absorbing aerosol layers in a changing climate: aging, lifetime and dynamics; 2017) and FIREX-AQ (Fire Influence on Regional to Global Environments and Air Quality; 2019). The algorithm automatically detects flight sequences in clouds and classifies the cloud type using size distribution measurements, combined with measurements of relative humidity and temperature. In addition, the cloud indicator algorithm was tuned and evaluated to successfully differentiate cloud sequences to those with enhanced concentrations of coarse mode particles (e.g. mineral dust, sea salt, or biomass burning layers).

In this study, we introduce the cloud indicator algorithm and present its ability to differentiate aerosol layers from clouds with a detailed analysis of unique measurements of ice clouds imbedded in a Saharan dust layer. Furthermore, we show first results of the analysis of the combined global-scale data set of ATom, A-LIFE and FIREX-AQ with regard to properties of aerosol-impacted cirrus clouds as well as properties of cirrus clouds in pristine environments.
The structure of the water budget of the Udy River (Ukraine) under the influence of present climate change
Authors: Bolbot Hanna , Grebin Vasyl
Published: March 2022

The water budget of a certain area for a certain time interval is one of the quantitative characteristics of the hydrological cycle, which reflects the objectively existing in nature relations between the inflow, losing, and change of humidity reserves.

The paper presents the results of calculating the components of the water budget of the Udy River Basin (the Siverskyi Donets River Basin) based on the available observation materials, and also describes their long-term dynamics. Total evaporation was calculated from the temperature and absolute humidity by the Konstantinov method. For the study, four meteorological stations data, which zones of influence belong to the studied basin, and the hydrological gauge the Udy River - Bezlyudivka data were used. In order to identify changes that have already occurred with the water body, it was compared the hydrometeorological characteristics of the present period (1991-2020) with the period of climatological normal (1961-1990).

Since meteorological stations observations characterize discrete values ​​of meteorological indicators at individual points, and hydrological gauges observations show integrated values ​​of water runoff related to the upper basin situated, meteorological data were reduced to their average values ​​in the river basin. For this purpose, the weighing method was used - the basin is graphically divided by the system of Thiessen triangles into zones of influence of a separate meteorological station within the studied basin. The amount of precipitation, temperature, and relative humidity were determined using the calculated weights coefficient.

The study of the water budget of the Udy River Basin revealed an increase in air temperature within the basin and the associated increase in the value of total evaporation, a decrease in spring flood runoff, and an increase in total runoff of the low-water period. It is determined that the annual runoff in the present period has decreased by 17%. The total amount of precipitation for the two study periods is characterized by the same amount, but there was a change in their distribution during the year. The amount of precipitation decreased in the period of spring flood at the present period compared to the period of climatological normal and increased in the low-water period.
Leveraging the transformative potential of shocks: a conceptual framework to reach the adaptigation goal
Authors: Thaler Thomas , Posch Eva , Seebauer Sebastian , Winkler Claudia
Published: March 2022

Recent examples of climate-driven catastrophes both internationally (e.g. US and Australian wildfires in 2020) and nationally in Africa or Europe, as well as climate scenarios highlight that climate change impacts will likely reach dimensions which pose substantive shocks to social, economic and ecological systems in the near future. At some point, this increased number of shocks will overstretch current individual and collective coping capacities. However, on the other side catastrophic shocks may enable the transformation to decarbonisation and resilience of our society, if the rebuilding phase after an event is used for a broad societal transformation process and not only for quickly bouncing back to the pre-shock situation. A rushed return to normality may come at the cost of forgoing lengthy and challenging transformation processes, which may ultimately reorient a system to higher resilience. Fast recovery from shocks typically mobilizes extensive resources but often lacks an integrated perspective on climate change adaptation and mitigation policies (‘adaptigation’) that could leverage synergies and build up for long-term responses to climate impacts. Instead, many policies implemented after shocks act in isolated or even competitive silos, cater to immediate demands by affected citizens and businesses, and have different goals, instruments, financial resources, administrative practices, time perspectives, or lack of imagination how to implement. The aim of the paper is therefore to illustrate how the transformative potential of shocks can be leveraged to lower carbon emissions, higher climate resilience and encompassing adaptigation policy. This contribution presents a conceptual framework that focuses on the interaction between the individual actors affected by a shock, and the policy instruments in place in the aftermath of a shock. We strive to learn from past and current reactions to inform the future with the aim of directing post-shock learning to transformation outcomes and to avoiding maladaptation, backfire or inaction pitfalls. The paper derives guidance how to leverage the transformative potential of shocks by dedicated policy action, in order to promote outcomes congruent with the Sustainable Development Goals and the targets of European and Austrian climate change mitigation and adaptation strategies. The conceptual framework can be expected to apply to a wide range of emerging, novel or familiar shocks.
Sensitivity Analysis on Air Quality Index Calculation
Authors: Eren Ozge
Published: March 2022

Ambient air pollution (AAP) is one of the greatest environmental risk for human health and well-being   for both cities and rural areas. According to the World Health Organization (WHO), AAP levels exceed recommended limits almost 92% of the world’s population. The Air Quality Index (AQI) is a simple, unitless index divided into six categories corresponding to a different level of health concern with a specific a specific color. There are lots of calculations to measure AAP and one of them, widely used in the world, is provided from EPA (U.S. Environmental Protection Agency).  EPA establishes an AQI for five major air pollutants ( ground-level ozone particle pollution (PM2.5 and PM10), carbon monoxide, sulfur dioxide nitrogen dioxide) regulated by the Clean Air Act. In this calculation, the highest AQI calculated for each pollutant constitutes the AQI value for that day. This calculation also brings sensitivity problems. This situation causes us to question the precision of the measurement. The main aim of this study is to show some calculation examples of concentration levels of the pollutants with the different cases. Thanks to these scenarios, the necessity of a much more precise measurement will be revealed.
Refractive static Fourier transform spectrometer: a balloon borne application
Authors: Frassetto Fabio , Cocola Lorenzo , Claudi Riccardo , Da Deppo Vania , Zuppella Paola , Poletto Luca
Published: March 2022

Static Fourier Transform spectrometers are traditionally realized with reflecting diffractive gratings. The positive aspects of these instruments, wide field of view and the absence of moving parts, are tested on an optical configuration in which the diffractive-reflective gratings are replaced with refractive-reflective prisms (Littrow prisms).

Beside the reduction in the resolution power, especially in the near IR, due to the dispersive power of the glasses, the optical quality of Littrow prisms can provide low noise instruments at low price.

The application to a sounding balloon flight on the Hemera project is presented. The flight took place in October 2021 at the CNES "Centre d'Opérations Ballons" at Aire sur l’Adour, France.

This work has been supported by ASI, Agenzia Spaziale Italiana, Agreement n. 2019-33-HH.0. for the payload realization and the flight opportunity has been provided by the European Commission in the frame of the INFRAIA grant 730790-HEMERA.
Tip-to-base conduit widening and spatial distribution of xylem conduits along the stem of Fagus sylvatica L.
Authors: Pericolo Osvaldo , Rita Angelo , Tumajer Jan , Ripullone Francesco , Gentilesca Tiziana , Saracino Antonio , Nola Paola , Borghetti Marco
Published: March 2022

Xylem is a multifunctional tissue that allows water transport, mechanical support, and storage of nutrients. These functions are provided by different cells, with different anatomy among species but also within individual trees. For the latter, it is well established that such anatomical disposition does not remain fixed but it is subject to a suite of adaptations induced by physiological constraints driven by both ontogenetic development and environmental characteristics.

For these reasons, in this study, we assessed 1) the spatial distribution of xylem conduits and their aggregation inside Fagus sylvatica L. tree-rings, and 2) the systematic variation of tip-to-base conduit widening and conduit packing occurring during tree growth.

In order to achieve these goals, we quantified the axial and radial xylem conduit patterns through measurement of conduit anatomical characteristics inside every tree-ring along complete radial series taken at different stem heights in eight Fagus sylvatica L. trees, sampled from two different sites in the Italian Apennines.

Our results showed a significant effect of the distance from the tree base and a weak effect of cambial age on the nearest neighbour distance among xylem conduits, suggesting that conduits were closer to each other near the apex, and became progressively more distant toward the base. However, point pattern profiles clearly highlighted a lack of aggregation between conduits along the stems.

In addition, the axial scaling of conduits (β) follows a power trajectory according to the theoretical prediction, while the xylem conduits packing exponent (α) was lower than the predicted Sperry’s packing rule. Furthermore, no consistent trend was found for the scaling exponent (β) during tree ontogeny, confirming that tip-to-base conduit widening is an adaptation, favored by natural selection to minimize the increase in hydraulic resistance when the individual stem grows longer and conductive path length increases.
A dynamic system theory approach to identify contaminant trapping zones in Vembanad Estuary using Lagrangian Coherent structures
Authors: Shukla Manish , Bairwa Arvind , Khosa Rakesh
Published: March 2022

Vembanad Estuary is located in the southern part of India and is also the country's longest lake. Its outlet to the Arabian sea is near Cochin. Particle trapping is one of the main issues found in this estuary. It causes the contaminants to stay in the region for extended durations, which can cause multiple problems. A large number of pollutants enter the Vembanad estuary due to the six rivers that discharge in the Vembanad lake. It is essential to comprehend the movement of these contaminants through the estuary to identify their effect on aquatic ecology and water quality. Flow in the lake is affected by numerous forcing parameters like inflowing rivers, tides, and other boundary conditions. The lack of standard methods to model particulate flow in such a complex environment poses a challenge in understanding flow dynamics and requires identifying new modeling methods.

In the present work, various sections of Vembanad are simulated to identify the trapping zones of the system. Lagrangian simulations of these individual parts of the lake are performed. The simulation results are further analyzed to obtain Lagrangian coherent structures (LCS) using Finite-Time Lyapunov Exponents (FTLE). LCS based on maximum FTLE values shows the dynamic boundaries present in the system, which help identify regions where potential trapping of non-inertial contaminants can occur. Lagrangian particle tracking also aids in recording the total movement of particulate matter from its initial position, which is used to find the resident time of these particles. The result of the study can also be used to find the potential risk posed by the non-inertial contaminants at a location based on their resident times.   
Multi-source soil moisture data fusion based on high-resolution land surface simulation and machine learning
Authors: Zeng Junhan , Xing Yuan , Ji Peng , Shi Chunxiang
Published: March 2022

Soil moisture (SM) plays an important role in hydrological processes and land-atmospheric interactions, and serves as an important boundary condition for the weather forecasting and climate modeling. Influenced by global environment change, SM changes significantly at local scales which rises the great need of high-resolution SM products to provide locally relevant information. However, the three SM estimation approaches, namely in-situ observation, remote sensing retrieval and land surface modeling, all have their disadvantages. Although recent works produce a combined SM products by merging the in-situ observations and several land surface simulation products, the long-term high-resolution SM product integrating multivariate data including remote sensing products is still lacking. In this study, high-resolution land surface modeling, high-resolution remote sensing products and SM observations from more than 2000 stations will be combined to generate spatially continuous and temporally complete soil moisture data in China by using the random forest algorithm. We first performed land surface simulations by using the Conjunctive Surface-Subsurface Process version 2 (CSSPv2) model forced by three meteorological forcings including the China Meteorological Administration Land Data Assimilation System version 2.0 (CLDASv2.0), ERA5 and GLDASv2.1. The validations over 2090 in situ stations during 2012–2017 showed that CLDASv2.0/CSSPv2 soil moisture simulation performed better than ERA5 and GLDASv2.1 reanalysis products, with an increased correlation of 26%–68% and reduced errors of 14%–24% at the daily time scale. The improvements mostly originate from the use of an advanced LSM because CLDASv2.0/CSSPv2 only increased the correlation by 5%–35% and decreased the errors by up to 9% when compared with ERA5/CSSPv2 and GLDASv2.1/CSSPv2. Due to the high accuracy of CLDASv2.0/CSSPv2 product, it will be used as a background to fuse the in-situ observations and satellite remote sensing soil moisture. The 70% of the observation site data, remote sensing products and CLDASv2.0/CSSPv2 product will be used to train the random forest model and generate a high resolution soil moisture product from 2008 to 2017, and another 30% of the site data will be used to evaluate the accuracy of the results. Such a SM product can describe the spatial and temporal distribution characteristics of soil moisture heterogeneity more accurately, and thus provide sufficient data support for scientific research and social development.
Assessment of Suitability of Hydrological Models for Climate Change Impact Studies  
Authors: Todorović Andrijana , Grabs Thomas , Teutschbein Claudia
Published: March 2022

Effective water resources management and mitigation of adverse effects of global warming requires accurate flow projections. These projections are generally focused on statistical changes in hydrologic signatures (e.g., 100-year floods, 30-year or 7-day minimum flows), which are obtained from statistical analyses of simulated flows under baseline and future conditions. However, hydrological models used for these simulations are traditionally calibrated to reproduce entire flow series, rather than statistical properties of the hydrologic signatures. Therefore, there is a dichotomy between criteria for hydrological model evaluation/selection and the actual requirements of climate change impact studies.

Here, we address this dichotomy by providing novel insights into the assessment of model suitability for climate change impact studies. Specifically, we analyse performance of numerous spatially-lumped, bucket-style hydrological models in reproducing observed distributions and trends in the annual series hydrologic signatures relevant for hydrologic impacts studies under climate change. Model performance in reproducing distributions of the signatures is evaluated by applying the Wilcoxon rank sum test. We consider that a model properly reproduces trends in the series of signatures if either series of observed and simulated signatures both exhibit lack of statistically significant trends, or both series exhibit statistically significant trends of the same sign. Statistical significance of the trends is estimated by applying the Man-Kendall test is used, while signs of the trends are obtained from the San slope. Model performance is also quantified in terms of commonly used numerical indicators, such as Nash-Sutcliffe or Kling-Gupta coefficients.

Our results, which are based on streamflow simulations in 50 high-latitude catchments in Sweden, show that high model performance quantified in terms of traditional performance indicators does not necessarily imply that distributions or trends in series of hydrologic signatures are well reproduced, and vice-versa. Therefore, these two aspects of model performance are distinct and complementary, and they require separate evaluation analyses. Accurate reproduction of statistical properties of hydrologic signatures relevant for climate change impact studies is essential for improving the credibility of future flow projections. We, therefore, recommend that the traditional process of selecting hydrological models for the impact studies should be enhanced with assessments of model ability to reproduce distributions and trends in the hydrologic signatures.
Evolution of the critical torus instability height and CME likelihood in solar active regions
Authors: James Alexander , Williams David , O'Kane Jennifer
Published: March 2022

Aims: Working towards improved space weather predictions, we aim to quantify how the critical height at which the torus instability drives coronal mass ejections (CMEs) varies over time in a sample of solar active regions.

Methods: We model the coronal magnetic fields of 43 active regions and quantify the critical height at their central polarity inversion lines throughout their observed lifetimes. We then compare these heights to the changing magnetic flux at the photospheric boundary and identify CMEs in these regions.

Results: We find higher rates of CMEs per unit time during phases when the critical height is falling rather than rising, and when magnetic flux is increasing rather than decreasing. Furthermore, we support and extend the results of previous studies by demonstrating that the critical height in active regions is generally proportional to the separation of their magnetic polarities through time.
Building a new type of seafloor observatory on submarine telecom fiber optic cables in Chile
Authors: Rivet Diane , Barrientos Sergio , Sánchez-Olavarría Rodrigo , Ampuero Jean-Paul , Lior Itzhak , Bustamente Prado Jose-Antonio , Villarroel Opazo German-Alberto
Published: March 2022

In most subduction zones, a great portion of seismicity is located offshore, away from permanent onland seismic networks. Chile is not the exception; since the upgraded seismic observation system began operating in 2013, 35% of the ~7000 earthquakes with M≥3 recorded yearly were located offshore. Most importantly, the epicenters of the largest earthquakes (M>7.5) from 2014 to 2016 were located offshore as well.

The Chilean national seismic network is mainly composed of coastal and inland stations, except for two stations located on oceanic islands, Rapa Nui (Easter Island) and Juan Fernandez archipelago. This station configuration makes it difficult to observe in sufficient detail the lower-magnitude seismicity at the nucleation points of large events. Moreover, the lack of seafloor stations limits the efficiency of earthquake early warning systems during offshore events. These challenges could be overcome by permanently instrumenting existing submarine telecom cables with Distributed Acoustic Sensing (DAS).

Thanks to GTD, a private telecommunications company that owns a 3500-km-long network of marine fiber optic cables with twelve landing points in Chile (Prat project), from Arica (~ 18⁰S) to Puerto Montt (~ 41⁰S), we conducted the POST (Submarine Earthquake Observation Project in Spanish) DAS experiment on the northern leg of the Concón landing site of the Prat cable. This experiment, one of the first to be conducted on a commercial undersea infrastructure in a very seismically active region, was carried out from October 28 to December 3, 2021. Based on the longitudinal strain-rate data measured along 150 km of cable with a spatial resolution of 4 meters and a temporal sampling of 125 Hz, we present preliminary results of analyses to assess the possibility of building a new type of permanent, real-time and distributed seafloor observatory for continuous monitoring of active faults and earthquake early warning systems.
Late Pleistocene and Holocene landscape evolution at Lake Paravani (Lesser Caucasus, Georgia)
Authors: Gademann Daniel , Ustiashvili Nino , Navrotishvili Levan , Tiiu Koff , Elashvili Mikheil , Brückner Helmut , Laermanns Hannes
Published: March 2022

Lake Paravani is located in the Republic of Georgia at an altitude of 2073 m on the volcanic Javakheti Plateau (Lesser Caucasus). Although first studies were conducted at the lake the last years, many questions remain unsolved regarding to the sedimentation pattern and the landscape evolution in general. Hence, we aim to deepen the understanding of landscape genesis during the Holocene and beyond. Therefore, a coring transect of eight cores was taken in the southern part of the lake and two of these sediment cores, ICE001 and ICE006, were analysed with respect to (i) landscape, vegetation and climate evolution since the Pleistocene, and (ii) their processes. By using an applied multi-proxy approach, sediment properties in terms of granulometry, geochemical composition, magnetic susceptibility, organic content, and palynology were analysed.

The results suggest high lake levels for the period from about 28 to 16 ka BP, inferring a cold and humid climate in the Lake Paravani basin. The landscape was covered by glaciers, which act as drivers for the prevailing physical weathering while sparse vegetation and poorly developed soils dominated around Lake Paravani. Since 16 ka BP, a declining lake level is identified, from which a significant increase in aridity is inferred while temperatures remain constantly low. The accompanying shift of facies into the sublittoral establishes variable depositional conditions at the site of borehole ICE001. For this reason, the transition from glacial to interglacial is poorly recorded. Early and middle Holocene deposits were eventually eroded during lake level fluctuations. A palaeobeach facies at approximately 4.5 ka BP displays low lake level and indicates high aridity. The period from 4.5 ka BP to present was characterized by rising lake level to recent conditions. Furthermore, increasing productivity within the lake, as shown by the total organic content, indicates warmer temperatures, and consequently increasing intensity of chemical weathering. In addition, vegetation cover established and soils developed. 
Differential summer melt rates of ridges, first- and second-year ice in the central Arctic Ocean during the MOSAiC expedition
Authors: Salganik Evgenii , Lange Benjamin , Katlein Christian , Matero Ilkka , Regnery Julia , Sheikin Igor , Anhaus Philipp , Høyland Knut , Granskog Mats
Published: March 2022

During the melt season, sea ice melts from the surface and bottom. The melt rates substantially vary for sea ice ridges and undeformed first- and second-year ice. Ridges generally melt faster than undeformed ice, while the melt of ridge keels is often accompanied by further summer growth of their consolidated layer. This summer consolidation is related to refreezing of less saline meltwater, originating from snowmelt and ridge keel melt. We examine the spatial variability of ice melt for different types of ice from in situ drilling, coring, and from multibeam sonar scans of remotely operated underwater vehicle (ROV). Seven ROV scans, performed from 24 June 2020 to 28 July 2020 during the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC) expedition were analyzed. The area investigated by the ROV (400 by 200 m) consisted of several ice ridges, surrounded by first- and second-year ice. Seven ice drilling transects were additionally performed to validate ROV measurements. The maximum keel depth of the ridge investigated by ice drilling was 6.5 m. We show a substantial difference in melt rates of first-year ice, second-year ice, and sea ice ridge keels. We also show how ridge keels decay depending on keel depth, width, steepness, and orientation relative to the ice drift direction. These results are important for quantifying ocean heat fluxes for different types of ice during advanced melt, and for estimation of the ridge contribution to the total ice mass and summer meltwater balances of the Arctic Ocean.
Palaeosol evolution and human disturbance on Mediterranean coastal pedosequences (SW Sardinia, Italy)
Authors: Nicoll Kathleen , Mariani Guido Stefano , Mellis Rita Teresa
Published: March 2022

In the southwestern coast of Sardinia coastal sediments preserve evidence of geomorphic processes such as slope, colluviation and pedogenesis, as well as human activities. We present the preliminary results of an integrated approach focused on descriptive and analytical soil investigation together with micromorphological data, geoarchaeological investigations and landscape survey as part of a larger project aimed to characterise the geoheritage of the region. We describe palaeosol sequences related to stratal architectures that date back to the Late Pleistocene. Our goal is to gain information on landscape evolution in the area and the effect of human agency on the larger environment, as well as document hydroclimatic change.

At the current coastline level, the last marine transgression exposed marine sequences dated to the MIS5, later covered by fluvial and slope deposits throughout the last portion of the Late Quaternary. Several soil sequences show traces of recent colluvial events of anthropogenic origin. Such deposits contain pottery and other human made materials related to the Iron/roman age. These initial findings seem to suggest a strong control of human activity on environmental change in the area, not related to a single location but widespread in the landscape. This control was such to cover and take precedence over the natural pre-existing surface dynamics, thereby complicating the definition of Anthropocene in Sardinia. Further investigations would bring more light on the ways palaeosols can inform on the shifts in human land use and occupation. How has land use accelerated since the Bronze age? How can these palaeosequences inform us about anthropogenic processes overstepping natural ongoing surface dynamics?
Integrated surface and groundwater resources management in a coastal aquifer (Cap BonPeninsula-NE of Tunisia)
Authors: Khammessi Ichrak , Brouyère Serge , Aouissi Jalel , zghibi adel , Mirchi Ali , Chkirbene Anis , Merzougui Amira , Msaddek Mohamed Haythem , Habaieb Hamadi
Published: March 2022

Coastal aquifers are usually the main source of water supply for irrigation, drinking
and industrial purposes in coastal regions. They are often subject to overexploitation and
consequent quantitative and qualitative degradation. The groundwater flow system of the Chiba
watershed in the CapBon peninsula (NE of Tunisia) is a typical case of an overexploited aquifer,
where a piezometric depression exceeding -10 m (a.m.s.l) appeared has developed over the two
last decades. Among the numerous remediation tentatives, the SMART-WATER project aimed
to propose a remediation plan based on a smart monitoring and water-energy nexus solution
through the installation of smart energy and water meters (SEWM). This technology aims to
optimize groundwater pumping at a set of selected representative farming systems in the
watershed. In this context, a first coupled surface water-groundwater flow model has been
developed and applied, coupled with energy nexus for the irrigated Chiba plain. The model is
implemented using a dynamic coupling between MODFLOW WEAP and LEAP in order to
assess the SEWM system efficiency in reducing aquifer exploitation and electrical energy
consumption at farm level. Multi-objective calibration of the model using river discharge and
GW level data has yielded accurate simulation of historical conditions, and resulted in better-
constrained parameters compared to using either data source alone. Model simulations show that
crop water demand cannot be met during droughts due to limited GW pumping capacity, and that
increased GW pumping has a relatively strong impact on GW levels due to the small specific
yield of the aquifer. Groundwater and energy models have also revealed that, under different
management and climatic scenarios, electric energy consumption and groundwater table decline
are intricately connected. Despite the short monitoring period and the intermittence of the
received data, SEWMs have shown a promising role in monitoring groundwater pumping and
engaging farmers in energy saving and aquifer sustainability.
Implications of Acoustic Full Waveform Inversion on high-resolution Andaman datasets
Authors: Vats Vikas , Ghosal Dibakar , Kumar Sai
Published: March 2022

The biggest challenge in the upstream oil and gas industry is to obtain the highly resolved image of the subsurface. With the advancement of computation facilities, travel time tomography has been turned into a routine task in industry, in which long-wavelength velocity-depth models are obtained using the first arrivals of seismic phases. However, obtaining short-wavelength subsurface features is still a difficult task, especially in a complex geologic setup. Acoustic Full waveform inversion (FWI), which is based on the deterministic inversion theory can help to understand the finer details of the subsurface structure with a maximum resolution of half of the wavelength of propagating wave by exploiting detailed information from the seismogram. To test the reliability of this approach, we first carry out two 2-D synthetic tests: (1) on a model with a gradual increase in velocity with a 100 X 100 m low-velocity structure embedded at a depth of 400 m, and (2) on the Marmousi model. From the synthetic tests, we realize that our inverted models recover most of the features of the true models. This technique is further applied to industry-derived high-resolution 2-D seismic reflection datasets adjacent to Narcondam Island, which is a volcanic island located in the Andaman Sea. A group of volcanoes including Narcondam Island and the northern extension of the Alcock Rise surrounds a sedimentary basin. It is very difficult to obtain velocity distributions in such volcano-supported sedimentary basins because the lateral velocity gradient is very steep. Earlier studies reported evidence of a bright reflector and low-velocity region in the basin, but detailed velocity depth information from this region is still missing. Therefore, we first use a global optimization scheme to obtain a reliable initial velocity depth model as this is important to avoid cycle skipping in FWI. We also use complementary velocity models as the starting models and compare the outcome of these different models on the final results. We then comment on the strategies used to deal with non-linearity for such a scenario. Finally, we shed light on the tectonics associated with Narcondam offshore from the detailed FWI velocity-depth model.
Differences of antibiotic-adsorption properties on various soil organic carbon pools
Authors: Vancsik Anna Viktória , Szabó Lili , Pirger Zsolt , Bauer László , Jakab Gergely , Kondor Attila Csaba , Szalai Zoltán
Published: March 2022

The ever-increasing use of pharmaceuticals in the 21st century has led to growing concern about the environmental impact of pharmaceutical substances. In terms of their mechanism of action, antibiotics pose one of the most significant risks to the environment by altering microbiological conditions. Microbial degradation of organic matter in soil systems is the primary driver of the carbon cycle, so antibiotic pollution can significantly impact soil CO2 emissions. Soil organic matter is not a homogenous system; most soil organic carbon models separate different carbon pools with shorter and longer decomposition times. As previously published, different soil organic carbon pools may have different chemical properties, and therefore adsorption properties. This study focused on the adsorption properties of different soil carbon fractions.

Adsorption studies were performed on three fluoroquinolone antibiotics (ciprofloxacin, norfloxacin, ofloxacin) by batch and kinetic experiments on three Luvisol samples with different land use (arable, grassland, forest). The SOM fractionation was based on the Zimmermann procedure, and the batch and kinetic experiments have also been carried out on the fractions. The soil fractions were analysed by TOC, XRD, XRF, BET, FTIR during the adsorption. Langmuir and Freundlich models were applied on the equilibrium data. The kinetics data were analysed by pseudo-first and second-order kinetics models. The main parameters affecting adsorption were studied by principal component analysis. Our results suggest that the long-term carbon pools are most affected by the adsorption of antibiotics.

 

PREPARED WITH THE PROFESSIONAL SUPPORT OF THE DOCTORAL STUDENT SCHOLARSHIP PROGRAM OF THE CO-OPERATIVE DOCTORAL PROGRAM OF THE MINISTRY OF INNOVATION AND TECHNOLOGY FINANCED FROM THE NATIONAL RESEARCH, DEVELOPMENT AND INNOVATION FUND.
Plasmapause Surface Waves Triggered by Substorms
Authors: Hao Yixin , Zong Qiugang , Yue Chao , Zhou Xuzhi , Zhang Hui , Pu Zuyin , Shprits Yuri
Published: March 2022

In this study, we present in-situ measurement by Van Allen Probes showing that surface wave could oscillate the plasmapause and modulate hiss and electron cyclotron harmonic (ECH) waves. Plasmapause sur-face wave (PSW) in Ps6 band was observed during an intense substorm on 16 July 2017, accompanied with quasi-periodic emissions of hiss (positively correlated to plasma density) and ECH waves (anticorrelated to the density). Phase relation between magnetic field and velocity perturbations indicatesthat the PSW was an eigenmode between southern and northern ionosphere. Measurements from ground-based magnetometers suggest that such PSW propagates sunward at dusk flank and were excited around the expansion phase of an intense substorm. Addiational cases of PSWs are also presented to demonstrate that such waves are commonly observed near plasmapause and are likely to be related to substorm activities.
Towards integrating information about strain rates in PSHA models in Europe: comparison between seismic moment rates from ESHM20 model and geodetic estimates
Authors: Donniol Bénédicte , Socquet Anne , Beauval Celine , Piña-Valdès Jesús , Danciu Laurentiu , Nandan Shyam
Published: March 2022

Most national and international seismic regulations require quantifying seismic hazard based on probabilistic seismic hazard assessment (PSHA) methods. The probabilities of exceeding ground-motion levels at sites of interest over a future time window are determined by combining a source model and a ground-motion model. This research work aims at understanding how the measurement of strain rates by geodesy can provide constraints on the source model.

Earthquake catalogs, merging instrumental and historical data, are usually used to establish earthquake recurrence models. Although these catalogs extend over several centuries, the observation time windows are often short with respect to the recurrence times of moderate-to-large events and in some regions the recurrence models can be weakly constrained.

Here, we compute different realizations of strain rates maps over Europe using a combined velocity field (Piña Valdes et al., JGR submitted). These strain rates are compared to the source model of the new European seismic hazard model (ESHM20, Danciu et al. 2021). More precisely, the moment rates estimated from the earthquake recurrence models are compared to the geodetically-derived moment rates.

We explore the different uncertainties in both models. For geodesy, we integrate uncertainties on the velocities at each station, and the epistemic uncertainties on the different steps of the computation of the geodetic moment rate : filtering of the velocity field (outliers’ removal and smoothing) (Piña-Valdés et al, JGR submitted), parameters used to drive the strain inversion with VISR software (Shen et al. 2015), constants and formula used for the moment computation. The goal is to quantify the impact of each parameter uncertainty or decision on the moment computation.

The first results show that a correlation exists between the seismically and geodetically derived moment rates. In general, the main uncertainty is on the velocities at each stations, followed by the depth taken into account for the moment computation. In areas characterized by high activity, such as Betics or Apennines for example, the moment rates derived by both methods are comparable. In areas of lower activity, such as at the interior of plates, the error associated with geodetic measurements is of the same order of magnitude as the measured strain, and the relation between catalog-based and strain-based moment is not straightforward.
Groundwater and transmissivity exert a strong effect on drainage density and landscape evolution
Authors: Luijendijk Elco
Published: March 2022

The role of groundwater flow in landscape evolution and the evolution of stream networks has long been debated but is still uncertain. This contribution explores the role of groundwater in the evolution of stream networks using a new model code, GOEMod, that simulates coupled groundwater flow, overland flow and erosion. The model results show that groundwater flow exerts a strong control on drainage density in humid areas. Drainage density is inversely correlated with transmissivity. Stream networks evolve by a newly identified process named groundwater capture, whereby streams that receive more water and incise faster draw the watertable below adjacent streams, which causes these streams to fall dry. This process is more efficient in areas with high transmissivity due to a relatively flat watertable. This contribution also discusses sensitivity analyses that compare the importance of groundwater to other landscape evolution processes. In addition, a set of model experiments is discussed that explores the persistence of stream networks in response to changes in base level, groundwater recharge and other parameters. 
Laser ablation Lu–Hf dating reveals Laurentian garnet in subducted rocks from southern Australia
Authors: Brown Dillon , Simpson Alexander , Hand Martin , Morrissey Laura , Gilbert Sarah , Tamblyn Renée , Glorie Stijn
Published: March 2022

Garnet is a fundamental expression of metamorphism and one of the most important minerals used to constrain the thermal conditions of the crust. Here, we use innovative in-situ laser ablation ICP–MS/MS Lu–Hf geochronology to demonstrate that garnet in metapelitic rocks enclosing Cambrian eclogite in southern Australia formed during Laurentian Mesoproterozoic metamorphism. Garnet porphyroblasts in amphibolite-facies metapelitic rocks yield Lu–Hf ages between c. 1285 and 1240 Ma, revealing a record of older metamorphism that has been partially obscured by metamorphic overprinting during c. 510 Ma Cambrian subduction along the East Gondwana margin. Existing detrital zircon age data indicate the protoliths to the southern Australian metapelitic rocks were sourced from western Laurentia. We propose that the metapelitic rocks of southern Australia represent a fragment of western Laurentian crust, which was separated from Laurentia in the Neoproterozoic and incorporated into the East Gondwana subduction system during the Cambrian. The ability to obtain Lu–Hf isotopic data from garnet at acquisition rates comparable to those for U–Pb analysis of detrital zircon means, for the first time, the metamorphic parentage of rocks as expressed by garnet can be efficiently accessed to assist palaeogeographic reconstructions.