bluuebunny/crossref_metadata_2025 huggingface dataset:
Using random forest machine learning algorithm to help investigating the relationship between subglacial sediments and ice flow in Antarctica
Authors: Constantino Renata Regina , Tinto Kirsty J. , Bell Robin E.
Published: March 2022

The presence of subglacial sediments is important in enabling streaming ice flow and may be a critical controlling factor in determining the onset regions of ice streams. Improving our knowledge of the location of sedimentary basins underlying large ice sheets will improve our understanding of how the substrate influences the ice streams.  Advancing our understanding of the interaction between subglacial sediments and ice flow is critical for predictions of ice sheet behavior and the consequences on future climate change. To date, no comprehensive distribution of onshore and offshore sedimentary basins over Antarctica has been developed. The goal of this project is to use a combination of large-scale datasets to characterize known basins and identify new sedimentary basins to produce a continent-wide mapping of sedimentary basins and provide improved basal parametrizations conditions that have the potential to support more realistic ice sheet models. The proposed work is divided into three main steps. In the first step, the Random Forest (RF), a supervised machine learning algorithm, is used to identify sedimentary basins in Antarctica. In the second step, a regression analyses between aerogravity data and topography is done to evaluate the gravity signal related to superficial heterogeneities (i.e. sediments) and compare the results to the depth of magnetic sources using the Werner deconvolution method. Last, the correlation between sedimentary basins and ice streams is investigated. Here, we will present the preliminary results from Step 1. The Random Forest uses ensemble learning method for classification and regression. The classification rules for this present work are based on the geophysical parameters of major known sedimentary basins. First we classify the known basins with all available geophysical compilations including topography, gravity and magnetic anomalies, sedimentary thickness, crustal thickness, geothermal heat flux, information on the geology, rocky type and bedrock geochemistry, and then use the Random Forest machine learning algorithm to classify the geology underneath the ice into consolidated rock and sediments based on these parameters.
GLidar - Probing atmospheric convection in complex terrain 
Authors: Duscha Christiane , Pálenik Juraj , Kähnert Marvin , Spengler Thomas , Reuder Joachim
Published: March 2022

Convection is a major contributor to the overturning of heat, moisture, and momentum in the atmospheric boundary layer and is responsible for the formation of convective clouds and precipitation. However, the characteristic properties, the dynamics, and the processes that trigger and shape the development of atmospheric convection are still only sparsely sampled. In this study, we present an approach to probe and characterise atmospheric convection from both the Eulerian and the Lagrangian perspectives, utilising dual-doppler lidar observations combined with velocity estimates from paraglider and sailplane flight trajectories. Some of the evaluated flights involve additional sensors to sample temperature and humidity. The observations are obtained over the mountainous terrain of southwestern Norway. As a proof-of-concept, we demonstrate the capability of the dual-doppler lidar setup to accurately characterise atmospheric convection and to validate the complementing estimates from the flight tracks in complex terrain. The Lidar setup accurately resolves dynamic properties of the convective circulation with high detail, while the flight tracks resolve the dynamic (and static) properties of the convective updrafts.  
The influence of the North Atlantic on vegetation greening patterns in the northern high latitudes
Authors: Winkler Alexander J. , Borchert Leonard F.
Published: March 2022

Rising CO2 concentrations due to anthropogenic carbon emissions and the resulting warming raise expectations of an increase in biospheric activity in temperature-limited ecosystems. Early satellite observations since the 1980s confirm this expectation, revealing so-called "greening" trends of the high northern vegetation. However, since the early 2000s, these observational records show these greening trends have stagnated in high-latitude Eurasia (HLE), with many regions even reversing to browning trends. We propose here that decadal variations of the North Atlantic ocean could have contributed to these HLE browning trends. 

Our analysis shows that roughly 80% of HLE area has become drier in the last two decades compared to the previous decades. It is mainly in these drying regions that the vegetation exhibits browning trends. Satellite observations of vegetation and the ERA5 reanalysis show HLE browning to be concomitant with a stagnation of North Atlantic sea surface temperature (SST). North Atlantic SST was previously shown to potentially influence remote climate by modulating a circumglobal atmospheric Rossby wave train. Indeed, we find a precipitation decrease over Eurasia to potentially originate from this North Atlantic teleconnection, linking SST stagnation to the observed browning trend.

Next, we turn to fully-coupled Earth system models to assess the plausibility of the proposed cause-and-effect chain. We employ a pattern matching algorithm to select realizations with similar-to-observed North Atlantic SST variations from three large ensembles (MPI-GE, IPSL-LE, and CanESM5). These ensembles enable a clean separation of the unforced signal (internal variability) from the forced vegetation response (CO2 forcing). Our results show that realizations that closely resemble the observed North Atlantic spatio-temporal SST pattern also simulate the respective wave-train and associated precipitation patterns over Eurasia that cause HLE vegetation to change. Thus, the models confirm that unforced decadal variations of HLE vegetation can be modulated by North Atlantic SST via changes in precipitation patterns. In addition, model simulations suggest that the relative decrease in vegetation greenness is accompanied by a reduction in land carbon uptake, such that changes in North Atlantic SST ultimately affect the global carbon balance.

This study therefore demonstrates that the recently observed trend in HLE browning may well be due to an unforced signal originating from the North Atlantic. This implies that even decades-long trends in biospheric variables can emerge from natural climate variability and thus could be incorrectly attributed to an external forcing. This has major implications for the understanding of biospheric dynamics, including carbon uptake and release processes.
Record of Geomagnetic Instabilities during the Brunhes: preliminary results from IODP Expeditions 384 and 395C from North Atlantic Ocean
Authors: Di Chiara Anita , Satolli Sara , Friedman Sarah , Expedition 395 Science Party Science Party
Published: March 2022

Throughout its history, the Earth’s magnetic field has undergone changes in its polarity. These changes vary in scale, from millennial (excursions) to hundreds of thousands or millions of years (reversal). Constraining the chronology of these geomagnetic instabilities is fundamental to understanding Earth’s dynamo processes and their surface expressions. Moreover, a detailed geomagnetic instability time scale (GITS) refines its applicability as an accurate correlation and dating tool (magnetostratigraphy) for sedimentary and volcanic sequences and it is fundamental to understanding several aspects of past climate. Indeed, periods of geomagnetic instability are usually associated with a weak field. This in turn weakens the efficiency of the Earth’s magnetic field shielding enhancing the production of cosmogenic isotopes which play a significant role on modulating climate by either directly or indirectly influencing factors such as the total or spectral solar irradiance. In this study, we present a preliminary record of geomagnetic instabilities during the Brunhes (0-0.778 Ma), based on intercorrelation of paleomagnetic data from five marine sedimentary cores collected during the IODP Expeditions 384 and 395C from the North Atlantic Ocean along the Reykjanes ridge. Two of the drilling sites are nearby the ODP Sites 983 and 984 (Channell et al., 2002) providing an opportunity to cross correlate our preliminary results.
A machine-learning approach for the reconstruction of ground shaking fields in real-time
Authors: Fornasari Simone Francesco , Costa Giovanni , Pazzi Veronica
Published: March 2022

Real-time monitoring is of primary importance for rapid and targeted emergency operations after potentially destructive earthquakes. A key aspect in determining the impact of an earthquake is the reconstruction of the ground shaking field, usually expressed as a peak ground parameter. Traditional algorithms approach this task by computing the ground shaking field from the punctual data at the stations and relying on ground motion prediction equations (GMPEs) computed on estimates of the earthquake location where the instrumental data are missing. The results of such algorithms are then subordinate to the evaluation of location and magnitude which can take several minutes.
To fill the gap between the arrival of the data and the (first preliminary) estimation (usually computed in a few minutes), we introduce a new data-driven algorithm that exploits the information from the station data only. Such an algorithm, consisting of an ensemble of convolutional neural networks (CNNs) trained with a database of ground shaking maps produced with traditional algorithms, can provide real-time estimates of the ground shaking field and the associated uncertainty. Since CNNs cannot handle sparse data a Voronoi tessellation of a specific peak ground parameter recorded at the stations is computed and used as an input to the CNNs; site effects and network geometry are accounted for using a (normalized) Vs30 map and a station location map, respectively.
The developed method is robust to noise, can handle network geometry changes over time without the need for retraining, and can resolve multiple simultaneous events. Although having a lower resolution, the results obtained are compatible with the ones from traditional methods. A fully-operational version of the algorithm is running on the servers at the Department of Mathematics and Geosciences of the University of Trieste showing real-time capabilities in handling stations from multiple Italian strong-motion networks and outputting results with a resolution of 0.05°x0.05°.
Swarm seismicity illuminates stress transfer prior to the 2021 Fagradalsfjall eruption, Iceland 
Authors: Fischer Tomas , Hrubcová Pavla , Salama Ali , Doubravová Jana , Horálek Josef , Agustsdottir Thorbjorg , Gudnason Egill , Gylfi Hersir
Published: March 2022

 

The 6 months long effusive volcanic eruption of 19 March 2021 at Fagradalsfjall, Reykjanes Peninsula, Iceland was preceded by an intensive earthquake swarm lasting one month, with several earthquakes exceeding ML 5. We analyse seismic data recorded by the Reykjanet local seismic network to trace the processes leading up to the eruption in order to understand the relation between seismic activity and magma accumulation.

 

The precise relocations show that the seismicity is located in two clusters in the depth range of 1-6 km. A NE-SW trending cluster maps the dyke propagation; a WSW-ENE trending cluster follows the plate boundary. In comparison, we relocated the preceding earthquake swarms of 2017, 2019 and 2020 and found that they form two branches along the plate boundary, coinciding with the 2021 WSW-ENE trending cluster. These branches form a stepover of about 1 km offset, forming a pull-apart basin structure at the intersection with the dyke. This is the exact location of the eruption site, which shows that magma erupted at the place of crustal weakening.

 

The 2021 earthquake swarm initiated by a ML 5.3 earthquake on 24 February, which triggered the aftershocks along the plate boundary and in the dyke segment, both occurring in an area of elevated Coulomb stress. The swarm seismicity shows complex propagation of the dyke, which started at its northern end, migrated south-westward and then jumped back to the central part where the effusive eruption eventually took place. The strike-slip focal mechanisms of the larger magnitude events, with N-S striking fault planes, are interpreted as right-lateral antithetic Riedel shears that accommodate the left lateral slip along the plate boundary. The fact that both seismic and magmatic activities occur at the same location shows that the past seismic activity weakened the crust in the area of the eruption site. We show that the ML 5.3 earthquake on 24 February 2021 triggered the whole seismic swarm and perturbed the magma pocket which eventually led to the 19 March Fagradalsfjall eruption.

 
Introducing robustness evaluation and archetype analysis in drought risk assessments
Authors: Villani Lorenzo , Castelli Giulio , Piemontese Luigi , Penna Daniele , Bresci Elena
Published: March 2022

Droughts have huge negative impacts on livelihoods and economies throughout the world, and climate change is expected to increase their future frequency and severity. For an effective drought management, drought risk assessment is considered of major importance. However, despite the high number of studies, shared and clear guidelines to perform drought risk assessments are missing, undermining the overall reliability of this procedure. A significant limitation common to most drought risk assessments is the lack of any form of validation. Moreover, checking the robustness of the assessment tools is of paramount importance, but appropriate data are usually not available for external validation; hence, internal validations are in many cases the only option. For this scope, we propose a simple but robust uncertainty analysis, using the methodology presented in the “Handbook on constructing composite indicators” of OECD (2008). An additional deficiency of most drought risk assessments is the missing link between the results and possible adaptation strategies. To address this limitation, we propose to use archetype analysis, which is an emerging approach for identifying recurrent patterns within cases and supporting a context-specific generalization of insights.  

The innovations introduced were applied to a drought risk assessment performed for the agricultural systems of five coastal watersheds of central and southern Tuscany, Italy. These watersheds are particularly prone to drought impacts because of the high concurrent water demand for domestic and agricultural uses during the summer months. To allow a better discretization, municipalities were selected as units of analysis. A total of 42 indicators were used to represent drought hazard, exposure, and vulnerability. Multiple drought hazard indicators were selected to estimate both past and future drought hazards, using ready-to-use data from public institutions. Overall, the southern part of Tuscany showed to be the most at risk, in particular the Grosseto province. For the robustness evaluation, we (1) excluded individual exposure and vulnerability indicators, (2) included the excluded indicators with the multicollinearity analysis, (3) assigned different weights, and (4) used an alternative aggregation method to calculate the composite risk indicator. Results in terms of average shifts in rankings and new rankings assigned revealed that the most uncertain parts were the selection of exposure indicators and the assignment of weights, but overall, the rankings were confirmed. The archetype analysis yielded as result seven clusters of municipalities; their characteristics were analysed and tailored adaptation strategies were proposed according to their specific drought risk profiles.
Analysis of ULF waves and SLAMS formation at Saturn
Authors: Bebesi Zsofia , Juhasz Antal , Timar Aniko
Published: March 2022

We present five events of SLAMS (short large-amplitude magnetic structures) detected upstream of the quasi-parallel bow shock of Saturn. The events were discovered and further analyzed using the measurements of the Cassini Plasma Spectrometer and the Magnetometer instruments of the Cassini spacecraft. Directional, speed and temperature analysis of the charged particles in the vicinity of the SLAM structures is presented. We also analyze the effect of upstream parameters (especially the IMF and cone angle) on the ULF wave frequency and subsequent SLAMS formation. We use a simple empirical model to estimate location of the bow shock related to the SLAMS observations. We also discuss the spatial characteristics of SLAMS observed near Saturn by extrapolating the measurements and morphology derived by the four Cluster probes at Earth.
Evolution of the Nile River since 70 Ma: insights from surface processes and anorogenic reliefs controlled by mantle dynamics
Authors: Setiawan Iwan , Guillocheau François , Robin Cécile , Braun Jean
Published: March 2022

Anorogenic reliefs (plateaus and plains) made up about 70% of the total emerged reliefs on Earth. They are characterized by nearly flat erosional surfaces upstream bounded by escarpments, called pediments/pediplains. Africa’s landforms are constituted by very long (several thousands of kilometers) wavelength relief of broad “basins” (depressions) and swells (Holmes, 1944) possibly controlled by mantle dynamics. This "basin" and swell pattern caused Africa to be consisted of numerous endorheic and exorheic systems. Consequently, the Nile River, the longest river on Earth and main object of this study, crosses today a set of two former endorheic systems (Ugandese and Sudanese “Basins”) and one exorheic system (Egyptian Margin) along its courses to the Mediterranean Sea. Our objective is here to unravel the paleorouting systems of the Nile River through relief growth, tectonic, and climate since the uppermost Cretaceous.

Several generations of stepped pediments, proxies of relief growth, were characterized and mapped on DEM and satellite images and dated using their geometrical relationships with dated magmatic rocks. To better constrain periods of relief uplift and the deformation wavelength through time, the stratigraphic record of the sedimentary basins located in between two swells were studied using biostratigraphy and sequence stratigraphy. The originality of the approaches is to integrate data of all the source-to-sink (S2S) systems to produce a coherent scenario of the evolution of the Nile.

We proposed the following model for the evolution of the Nile River. First, a main large pediplain is formed during the uppermost Cretaceous (?75-66 Ma), acting as a base of any kind of landforms that would be formed afterwards, bounded westward by the Darfur-Ennedi crest. Second, a major marine flooding during late Paleocene time (58-57 Ma) reached a subtle high bounding northward the endorheic Sudanese “Basin”. Third, Pre-Eonile started to form during the uppermost Eocene (~37 Ma) with a divide limited to the Egyptian Margin. Fourth, the Eonile was incised during late Miocene (~10 Ma) at time of a major uplift at the scale of north-east Africa. Finally, the Nile captured first the Sudanese endorheic system in the Early Pliocene (~4 Ma) and altered the Ugandese one in the Middle-Late Pleistocene (less than 1 Ma).
Idealised modelling of freshwater pulses
Authors: Biemond Bouke , de Swart Huib E. , Dijkstra Henk A. , Dìez-Minguito Manuel
Published: March 2022

Freshwater pulses, during which the freshwater discharge by rivers exceeds three times its long-yearly average value for no longer than one month, are common features in many estuaries around the world. The goal of this study is to develop a tool to describe the salinity response to freshwater pulses. To this end, a new model is presented, which generalises a number of assumptions often used in studies of estuarine adjustment, but retains their idealised character. This model is applied to observed freshwater pulses in the Guadalquivir Estuary (Spain) and the effect of different assumptions is quantified. Results show that it is important to adequately simulate the vertical salinity structure during a freshwater pulse. Assuming the depth-averaged salinity at the estuary mouth to be fixed during freshwater pulses ignores important feedback mechanisms between river discharge and stratification at the mouth. Prescribing instead the salinity at the bottom only circumvents this problem.
More precisely comparing simulated and observed salt intrusion lengths shows that the idealised model captures the essence of the estuarine salinity response. Overall, the results indicate that the model can be used be used as a tool to quantify the dependence of the estuarine salinity response to different parameters. 
Scattering and Absorption Imaging of the North Anatolian Fault Zone, northern Turkey
Authors: Sketsiou Panayiota , Cornwell David , De Siena Luca
Published: March 2022

The North Anatolian Fault (NAF) is a right-lateral, strike-slip fault in the northern part of the Anatolian peninsula. It is estimated to have a length of up to 1500 km, extending westwards between the Karliova Triple Junction, where it nucleates, to the Aegean Sea. In the west and close to the Sea of Marmara, the NAF splays into northern (NNAF) and southern (SNAF) strands. The splay of the western part of the NAF separates the area into three primary terranes: the Istanbul Zone (north of the northern strand), the Armutlu-Almacik Block (between the two strands of the fault) and the Sakarya Zone (south of the southern strand).

There have been a series of high-magnitude earthquakes along the NAF since the 1930s, migrating from east to west. In order to investigate the western part of the North Anatolian Fault Zone (NAFZ), which is the most seismically active at the moment, the Dense Array for North Anatolia (DANA) temporary seismic network was deployed for 18 months between 2012 and 2013. A set of local earthquakes, recorded by DANA, were utilised to study the 2D scattering and coda attenuation structure in the western NAFZ, between 1 and 18 Hz. P-wave arrival times were manually picked and the events were re-located using the Non-Linear Location software. Peak-delay travel times were calculated as a measure of forward scattering, and the exponential decay of the coda wave envelopes was used to invert for the absorption structure using multiple scattering sensitivity kernels.

The obtained models are 2D averages of the first 10-15 km of the crust, where the majority of the seismic activity is located and they have been compared to recent geophysical studies in the same area. The scattering structure, between 1 and 6 Hz, highlights the three main tectonic units in the area. The absorption structure is generally more heterogeneous than the scattering structure, with the overall absorption decreasing as the frequency increases. The lithological variations and heterogeneity between and within the three terranes of the area, arising from the complex tectonic history of the region, are believed to be the main reasons for the scattering and absorption observations made. The high absorption zones observed along the two branches of the fault, and especially the southern branch, is a very important finding, as the signature of the southern branch in geophysical studies is often unclear.
Are average hydraulic parameters representative? A stochastic analysis of water balance components predicted by a hydrological model
Authors: de Jong van Lier Quirijn , Dos Santos Arthur Klebson Belarmino , Looms Majken Caroline
Published: March 2022

Vadose zone hydrological models employing finite difference numerical solutions of the Richards equation allow simulating the movement and predicting the state of soil water and associated quantities in the vadose zone. Robust algorithms are available to perform such simulations and most numerical issues with these have been solved. Parameters describing the relation between hydraulic conductivity K, pressure head h, and water content θ determine the quality of model output. We performed two case studies, one with maize in the southeast of Brazil (São Paulo State) evaluating a wet-year and a dry-year scenario, and one with soybean in the northeast of Brazil (Maranhão State). Parameters of the Van Genuchten-Mualem (VGM) relations were obtained from laboratory evaporation experiments with undisturbed soil samples. The parameter uncertainty was expressed as standard error and correlations between parameters were expressed in a correlation matrix. A previously developed stochastic framework was used to evaluate the outputs of the SWAP hydrological model according to the uncertainty and correlations in the VGM parameters. Performing runs with 105 stochastic realizations per scenario, we evaluated the predictions of evaporation, transpiration, bottom flux, and runoff and their frequency distribution with respective crops at both locations. Results will be discussed and show that no general conclusion can be drawn about the frequency distributions of soil water balance components as a result of the uncertainty of and correlation between VGM parameters. Skewed or multimodal distributions of output parameters are common, and the most commonly performed prediction using the average VGM parameter values does not always agree to the mean or median of stochastic realizations. Users of hydrological models should be aware of this propagation of uncertainty and correlation into the model outputs. The investigation of the representativeness of average VGM parameters in specific scenarios adds to the interpretation of the predictive power of hydrological models.
Public perceptions of flood and drought risk: Gender differences in Italy and Sweden 
Authors: Mondino Elena , Raffetti Elena , Di Baldassarre Giuliano
Published: March 2022

Hydrological extremes still cause severe damage worldwide. Understanding people’s perceptions of drought and flood risk, and their changes over time, can help researchers, practitioners, and policymakers assist communities at risk. In particular, identifying and highlighting gender differences in the perception of hydrological risk is fundamental to promote fair disaster risk reduction policies which take such differences into account. To this end, we collected national survey data three times over a year on risk perception, knowledge, and preparedness in regard to floods and droughts in Italy and Sweden. Preliminary results show that: i) the perceptions of drought and flood risk are heavily intertwined; and ii) women show a higher fluctuation in perception over time compared to men, especially when it comes to floods. These results and their implications show how important it is to integrate gender into the management of floods and drought and into risk communication, as well as to promote policies that simultaneously address flood and drought risk.
Anaerobic soil disinfestation benefits soil health while at a high environmental cost in solar greenhouse vegetable production systems
Authors: Wan Li , Zhao Yiming , Xia Longlong , Hu Jing , Xue Tongxin , Lv Haofeng , Butterbach-Bahl Klaus , Lin Shan
Published: March 2022

Vegetable production in solar greenhouses in Eastern China generally suffers from over-fertilization and unreasonable irrigation, which result in severe soil degradation and soil-borne pathogens occurrence. Anaerobic soil disinfestation (ASD), as a newly developed economic technique, can combat pathogens in greenhouse vegetable soils. The ASD can create strong reductive conditions through the decomposition of added fresh C sources (crop residues or livestock manure) under saturated irrigation and warm conditions induced by plastic coverage to kill soil pathogens. However, ASD-induced organic matters application may increase N leaching and greenhouse gas (GHG) emissions, which remains unknown. Here, we investigated the effects of combined application of two crop residues (rice shells/maize straw) with different amounts of dry chicken manure (0, 300, 600, 1200 kg N ha-1) on N leaching and GHG emissions losses in greenhouse vegetable production systems adopting ASD technique in Eastern China. Our results showed that seasonal N leaching and N2O emissions ranged from 144-306 kg N ha-1 and 3-44 kg N ha-1, respectively, which both significantly increased with manure application rate. Approximately 56-91% of seasonal N2O emissions occurred during the ASD period (5 weeks before vegetable transplantation), whereas 75-100% of total N leaching occurred in the following vegetable-growing season after ASD. The incorporation of crop residues significantly increased N2O emissions by 33-47% while decreasing N leaching by 26-27% compared with CK treatment. The application rate of chicken manure did not affect vegetable yield while significantly increasing the greenhouse gas intensity (GHGI) and reactive N losses intensity (NrI), with reducing 75% manure application significantly decreased 40-45% and 33-38% in GHGI and NrI, respectively. Our results demonstrate that overfertilization with conventional irrigation will not benefit the yield but at a high cost in environment N losses. Overall, current ASD schemes combined with additional manure and irrigation schemes need to be adapted to avoid GHG emissions and N leaching for reducing environmental pollution and improving the sustainability of greenhouse vegetable production systems.
Mortar damage to stone built heritage
Authors: Mol Lisa , Brassey Charlotte , Cunliffe Emma
Published: March 2022

Stone built heritage in conflict areas is increasingly at risk of accelerated deterioration, as explosive and ballistic damage not only create damage to the surface, but also inherently change the mineral fabric of the stone to deep within the structure. In particular, remotely detonated high-power explosive ordnance has become more accurate and economically viable for state forces, especially given the availability of remote-controlled military aircraft. Concurrently, armed non-state groups engaged in asymmetric warfare rely on (improvised) ground-based explosive devices, seen to devastating effect at high-profile sites like Palmyra.

Stone in historic buildings is pre-weakened through centuries/millennia of exposure to weathering, and may be particularly vulnerable to subsequent heat and shock waves generated by explosives. Whilst appearing unaltered externally, exposure to high-pressure explosive force can result in the growth of microfractures and loss of cohesion within the cement matrix of stone, potentially leading to fracturing and crumbling, particularly if such stones are load-bearing within a rebuilt structure. The loss of density associated with explosive damage is particularly problematic. We show that our preliminary testing of the effect of an 81 mm HE mortar bomb blast in the vicinity of sandstone structures indicates changes in rock surface hardness as well as complex fracturing of the surface. Both visible and non-visible damage were recorded using high speed cameras, rock surface hardness surveys pre- and post-detonation, and photogrammetry. We conclude that even if not directly exposed to an explosive blast, stonework can be inherently altered.

 
Resolution sensitivity of GRIST Nonhydrostatic Model During DYAMOND winter from 120 km to 5 km
Authors: Zhang Yi , Liu Zhuang , Li Jian
Published: March 2022

This work investigates the resolution sensitivity of an explicit dynamics-microphysics coupled system using the GRIST nonhydrostatic model, with varying uniform horizontal resolutions (120 km, 60 km, 30 km, 15 km, 5 km). The experiments follow the DYAMOND (DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains) winter protocol that covers a 40-day integration from UTC00, 20th  to UTC00, Jan to 29th, Feb, 2020. The five simulations did not activate parameterized convection, and no specific tuning of model physics is employed such that the direct resolution response of a fixed model system can be examined. One 120-km run with parameterized convection is done to serve as a coarse-resolution reference. Other model configurations for different runs are kept as consistent as possible except certain small differences. Results demonstrate that the model gradually improve its representation of the fine-scale features (e.g., kinetic energy spectra) as resolution increases. In terms of 40-day averaged climate, the 5-km run has an overall more realistic simulation of the rainfall distribution than lower-resolution simulations without parameterized convection (e.g., spatial distribution). Most zonally averaged climate statistics are less prone to be altered by the resolution, except those fields associated with cloud water (e.g., shortwave cloud radiative forcing). This finding was also reached by an earlier study using the ICON model. Though with better fine-scale details, the coarse-resolution averaged features of the 5-km model without parameterized convection do not necessarily (and automatically) gets better than a 120-km simulation with parameterized convection. The tropical rainfall frequency-intensity spectra become more realistic in the 5-km no-convection run, but the 120-km run with parameterized convection shows a more realistic zonally averaged mean state. This impies more development and tuning efforts are still required for global km-scale models.
Investigating earthquake clusters complexity in Central Italy by network theory tools
Authors: Varini Elisa , Peresan Antonella
Published: March 2022

Complex network theory has been recently applied to get new insights and a different perspective in the study of earthquake patterns. Several studies (see for instance Daskalaki et al., J Seismol, 2016; Telesca, Phys. Chem. Earth, 2015; Varini et al., J Geophys Res, 2020; Ebrahimi et al., Chaos Solitons Fractals, 2021, and references therein) were based on the preliminary mapping of the time series of earthquakes into networks, by applying visibility graph method or other clustering algorithms. In a second step, the topological properties of the obtained networks were analyze by exploiting tools of complex network theory with the aim of discovering possible precursory signatures of strong earthquakes or other features relevant to hazard assessment.

In this study we investigated the earthquake clusters extracted by two data-driven declustering algorithms: the nearest-neighbor, which classifies the earthquakes on the basis of a nearest-neighbor distance between events in the space-time-energy domain (Zaliapin and Ben-Zion, J Geophys Res, 2013), and the stochastic declustering, which is based on the space-time ETAS point process model (Zhuang et al., J Geophys Res, 2004). Case studies from selected sequences, occurred in Central Italy from 1985 to 2021, are examined in some detail.

The earthquake clusters extracted by the two declustering algorithms are compared by different tools, so as to assess the similarities and differences in their classification and characterization (Varini et al., J Geophys Res, 2020). The connections between events forming a cluster, as defined by the considered declustering method, allow us representing its hierarchical structure by means of a tree graph. The topological structure of the clusters is then investigated by means of centrality measures in the frame of Network analysis.
Islands of proglacial lake Ojibway acted as outposts favoring postglacial forest migration in northwestern Québec
Authors: Vogel Marianne , Ali Adam A. , Joannin Sébastien , Bergeron Yves , Asselin Hugo
Published: March 2022

At the beginning of the Holocene, the Laurentide Ice Sheet was progressively melting and liberating Canadian landscapes. Proglacial Lake Ojibway formed at the contact of the glacier and covered western Québec and eastern Ontario for approximately 2000 years before flushing into James Bay around 8,200 years ago. Lake Ojibway could have limited the afforestation of newly liberated landscapes but could have also provided migratory outposts on its islands. Indeed, several islands were present on Lake Ojibway which could have been colonized by forests before the drainage of lake Ojibway. We studied lake sediments from a small lake located on a paleo-island of Lake Ojibway in Aiguebelle National Park, in order to test the outpost hypothesis. Radiocarbon dating, XRF analysis and charcoal analysis reveal that organic matter (gyttja) started to accumulate around 9,626 years before today (i.e., 1400 years before Lake Ojibway retreat). The signatures of Ca, Sr and Si indicate that soil erosion declined between 9500 and 9000 years before present, meaning this paleo-island was probably colonized during this interval as vegetation stabilizes the soils. Moreover, K (an indicator of vegetation extension) also suggests that afforestation occurred around 9,250 years before present. Macroscopic charcoal particles reveal that one local fire likely occurred 9239 years before present. Burned conifer needle fragments were found among the fossil charcoals, lending support to the hypothesis of wildfire occurrence. All the studied indicators suggest paleo-island colonization around 9,250 years before present, more than 1,000 years before Lake Ojibway retreat.
Variations of 7Be concentration in plants and its significance for 7Be in soil on the Loess Plateau, China: Based on three-year monitoring data
Authors: Li Xuantian , Zhang Fengbao , He Yanxing , Delang Claudio O , Yang Mingyi
Published: March 2022

Aims  With the wide application of 7Be (Beryllium-7) in soil erosion investigations, absorption and interception of 7Be by vegetation play an important role in documenting soil 7Be redistribution, with a large impact on the precision of 7Be measurements. However, the dynamic changes in plants and the relationship with soil 7Be concentration remain unclear, and the significance of dead plants in 7Be interception is under-researched.

Methods  The samples of 6 plant species, multi-plants (including living, dead and both mixed) and soil reference on the Loess Plateau were collected to analyze the variations of 7Be content during the growth period from 2010 to 2012.

Results  The accumulation of 7Be concentration is significantly higher in leaves than stems. The 7Be mass and areal activity concentrations in multi-plants with seasonal trends ranged from 173.9 to 964.5 Bq kg–1 and 21.5 to 440.1 Bq m–2. Precipitation accounted for the largest contribution to the accumulation of 7Be in plants, followed by plant growth, species and parts. Plants accounted for 7Be interception on slope up to 66% (living plants accounted for 7%~31% and dead accounted for 6%~44%). The interception of living plants is low at first, then increases with biomass accumulated.

Conclusions  Our results highlight that 7Be concentration in plants has great implications for 7Be in soil, and is subject to precipitation, growth status and plant characteristics. The reference information obtained in this work will contribute to improving the accuracy of 7Be tracer technology, and broadening the application scope and scale of 7Be tracer technology.

Keywords  Beryllium-7 · Loess Plateau · Precipitation · Plant · Activity concentration
OCELAND: A Conceptual Model to Explain the Partitioning of Precipitation between Land and Ocean 
Authors: Schmidt Luca , Hohenegger Cathy
Published: March 2022

The spatial distribution of precipitation is often misrepresented by General Circulation Models. In particular, precipitation tends to be underestimated over land and overestimated over ocean.

In this study, we investigate whether large-scale constraints on the partitioning of precipitation between land and ocean exist by using a conceptual box model based on water balance equations. With a small number of empirical but physically motivated parametrizations of the water balance components, we construct a set of coupled ordinary differential equations which describe the dynamical behavior of the water vapor content of land and ocean atmospheres as well as the soil moisture content of land. We compute the equilibrium solution of this system and analyze the sensitivity of the equilibrium state to model parameter choices.

Our results show that the precipitation ratio between land and ocean is primarily controlled by the land fraction, a scale-dependent atmospheric moisture transport parameter and the permanent wilting point of the soil. We demonstrate how the proposed model can be adapted for applications on both global and local scales, e.g. to model island precipitation enhancement. For a global scale model configuration with one ocean and one land domain, we show that the precipitation ratio is constrained to a range between zero and one and are able to explain this behavior based on the underlying equations and the fundamental property of land to lose water through runoff.
Organic versus conventional food emissions under different carbon footprint metrics
Authors: Chiriacò Maria Vincenza
Published: March 2022

One of the most well-known and appreciated characteristics of organic food is the lower pesticide residual which reduces the risks for human health. Moreover, the main benefit clearly recognized to the organic farming is the environmental sustainability compared to conventional ones, with a minor pressure of chemicals, reduced negative impacts on biodiversity and water quality and improved agricultural soil and vitality. However, the effect of organic farming on global warming and climate change mitigation is instead a still open debate in the scientific community. Depending on the boundary of the study, the adopted methodology, the soil and climatic characteristic of the agrosystem, the analyzed crops and the availability of primary data, different studies in literature provide diverse and even opposite results: organic farming is considered to perform better in some cases and worse in other cases in terms of contribution to climate change, compared to conventional farming.

The carbon footprint (CF) is one of the most used indicators to measures the contribution to climate change in terms of GHG emissions with different metrics (e.g. GHG per unit of product or per unit of land). With the aim to contribute to a more informed debate on the actual contribution to climate change in terms of GHG emissions of organic and conventional agriculture, we carried out a systematic analysis of the existing peer-reviewed studies allowing an unbias comparison of product-based vs land-based CF.

The results of the review show that organic food has on average lower impact on climate than conventional ones both when the CF is assessed per area unit (-43% GHG emissions, average) and per product unit (-12% GHG emissions, average), solving the existing scientific debate in favor of the organic food production, being more sustainable both in terms of total climate altering gases released in atmosphere and in terms of GHG emission intensity per product.

According to these results and in view of the global climate policies’ targets which foster organic food production and the transition to sustainable diets, a potential full conversion of the actual global croplands into organic lands would nearly halve the emissions from the land sector, from the current 11 GtCO2eq yr–1 to 6 GtCO2eq yr–1.
Subduction as Observed at a Submesoscale Front in the Marginal Ice Zone in Fram Strait
Authors: Hofmann Zerlina , von Appen Wilken-Jon , Iversen Morten , Hufnagel Lili
Published: March 2022

The marginal ice zone in Fram Strait is a highly variable environment, in which dense Atlantic Water and lighter Polar Water meet and create numerous mesoscale and submesoscale fronts. This makes it a model region for researching ocean frontal dynamics in the Arctic, as the interaction between Atlantic Water and the marginal ice zone is becoming increasingly important in an "atlantifying" Arctic Ocean. Here we present the first results of a front study conducted near the ice edge in central Fram Strait, where Atlantic Water subducted below Polar Water. We posit that the frontal dynamics associated with the sea ice edge also apply beyond, both to the open and the ice-covered ocean in the vicinity. They, in turn, can affect the structure of the marginal ice zone. The study comprises a total of 54 high resolution transects, most of which were oriented across the front. They were taken over the course of a week during July 2020 and include current velocity measurements from a vessel-mounted ADCP. Most of the transects also include either temperature and salinity measurements from an underway CTD, or temperature and salinity measurements and various biogeochemical properties from a TRIAXUS towed vehicle. Additionally, 22 CTD stations were conducted, and 31 surface drifters were deployed. This wealth of measurements gives us the opportunity to follow the temporal and spatial development of the density fronts present at the time. We discuss the dynamics of the frontal development, including the associated geostrophic motion, and the induced secondary ageostrophic circulation with subsequent subduction of Atlantic Water and biological material in a highly stratified region. Beneath the stratified upper ocean, subduction is clearly visible in the biogeochemical properties, and water samples indicate a substantial vertical transport of smaller particles. Surface drifters accumulated in locations of subduction, where sea ice, if present, would likely also accumulate. Our study thus demonstrates the importance of frontal dynamics for the vertical transport of water properties and biological material, and the highly variable development of the marginal ice zone in Fram Strait.
Influence of climate conditions and lake characteristics on the former lignite mining pit Lohsa I
Authors: Jarosch Lisa , Scheytt Traugott
Published: March 2022

In 2018 a mass death of fish occurred in the storage basin Lohsa I which is located in the Upper Lusatia, Germany. Lohsa I is a former lignite mining pit, which is now mainly used for industrial water supply, flood defence and fishing. It was assumed that an inflow of anaerobic groundwater could have been the cause for this event as groundwater inflow was observed before. Additionally, the input of fresh water from the river Kleine Spree was missing in summer 2018. In the project RoBiMo (robot assisted inland water monitoring) at the TU Bergakademie Freiberg there is a focus on collecting and analysing water quality data and climate data with the aim to quantify groundwater - surface water interactions and identify the influence of climate change in Saxony.

With an annual mean temperature of 12.4°C the year 2018 was +1.3°C warmer than the former period from 2010 to 2017. Total precipitation in 2018 was 398 mm, only 61% of the average precipitation of the period between 2010 and 2017 (648 mm). These data were used to quantify the amount of groundwater inflow to the storage basin Lohsa I and the effect of climate change.

For 2018 a positive value of groundwater flow was determined which implies an inflow of groundwater. A calculation from 1996 to 2019 shows an overall net inflow of groundwater. The calculation figures out a strong coherence between the groundwater flow, precipitation and sea water level. Until 2018 groundwater inflow and outflow were balanced but since then it became more deficient. The model BOWAHALD was used to determine evapotranspiration and storage change. The linear trend of precipitation is decreasing whereas the trend for evapotranspiration is increasing. As a result, the storage basin Lohsa I experiences a net loss of water.

Based on the results from storage basin Lohsa I the water budget for Upper Lusatia is calculated. Less precipitation, heavy rainfall events and decreasing groundwater levels are predicted for this area. The Lusatian lakes with 23 post mining lakes and a water surface area of more than 14,000 hectares will be heavily affected by climate change. For 2018 a loss of water to the atmosphere through evapotranspiration of 1.18 x 108 m³ was calculated. It can be assumed that such warm and dry years as 2018 will occur more frequently in the future.