bluuebunny/crossref_metadata_2025 huggingface dataset:
A comparative study of magma ascent and storage below impact craters on terrestrial planets
Authors: Le Contellec Alexandra , Michaut Chloé , Maccaferri Francesco , Pinel Virginie
Published: February 2023

On terrestrial bodies other than Earth, volcanism and magmatism are often related to impact craters. On Venus, RADAR observations of the surface have revealed two categories of craters: bright-floored and dark-floored craters, the latter being interpreted as partial filling of the crater by lava. On the Moon, volcanic deposits and evidence of pyroclastic activities are also frequently located within impact craters, especially within floor-fractured craters. These craters are characterized by uplifted, fractured floors resulting from underlying shallow magmatic intrusions. The elastic stress induced within the crust by a crater excavation indeed has two competitive effects. It induces a depressurization of the encasing elastic medium, which provides a driving pressure to the magma. This allows its ascent through the crust despite the magma’s negative buoyancy and explains why the magma tends to erupt preferentially within impact craters (Michaut and Pinel, 2018). However, the state of stress below the unloading is such that the minimum compressive stress is vertical at the unloading axis, which tends to horizontalize the dyke intrusion, therefore favoring magma storage below a crater at the expense of eruption.We calculated the stress fields generated by surface unloadings of different radius on top of a semi-infinite half-space and use them in numerical mechanical models of magma ascent (Maccaferri et al, 2011) to evaluate the path followed by a dyke below a crater. We identify several types of behavior (ascent to the crater floor, horizontalization of the intrusion, storage at depth, ascent to the planet surface) depending on the physical properties of the magma and crust, as well as on the dyke and crater unloading characteristics. We draw a regime diagram for magma ascent below craters as a function of two characteristic dimensionless numbers depending on these different physical parameters.Our results show that magma ascent to the crater interior requires relatively small density contrasts between the crust and magma and rather small crustal thicknesses as opposed to dyke horizontalization that results from larger crust-magma density contrasts and crustal thicknesses. Furthermore, on the Moon, craters are considerably deeper than on Venus, leading to a larger dimensionless deviatoric stress below a crater of a given radius, favoring dyke horizontalization and storage. This well explains why the magma tends to store as horizontal intrusions below floor-fractured craters on the Moon while it tends to erupt on the floor of dark-floored craters on Venus.ACKNOWLEDGMENT: This project has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 101001689).
Global assessment of the sensitivity of water storage to hydroclimatic variations
Authors: Thomas Brian , Nanteza Jamiat
Published: February 2023

Observing basin water storage response due to hydroclimatic fluxes and human water use provides valuable insight into how a basin stores and discharges water.  Quantifying basin storage change attributed to climate and use is critical for water management yet remains a challenge globally.  Observations from the Gravity Recovery and Climate Experiment (GRACE) mission are combined with hydroclimate fluxes of precipitation and evapotranspiration to document the sensitivity of available water storage for global basins.  Our results detect substantial global water storage sensitivity to changes in hydroclimatic fluxes.  Comparison with Budyko-derived metrics substantiate our findings, demonstrating that basin water storage resilience to short-term water deficits is linked to basin partitioning predictability, and uniform seasonality of hydroclimatic fluxes.  Our study demonstrates how small shifts in hydroclimate flux may affect available water storage potentially impacting billions globally.
On the importance of the atmospheric coupling to the small-scale ocean in the modulation of latent heat flux
Authors: Fernández Pablo , Speich Sabrina , Borgnino Matteo , Meroni Agostino , Desbiolles Fabien , Pasquero Claudia
Published: February 2023

In this study, we address the role of the ocean fine scales in north-west tropical Atlantic Ocean air-sea interactions. With this purpose, we use satellite observations of the ocean and the atmosphere, the ERA5 atmospheric reanalysis and a set of regional numerical simulations of the lower atmosphere. In particular, we focus on the coupling between the sea-surface temperature (SST) and the marine atmospheric boundary layer (MABL). We also evaluate the latent heat flux (LHF) sensitivity to SST. The results suggest that the SST-MABL coupling depends on the spatial scale of interest. At scales larger than the ocean mesoscale (larger than 150 km), negative correlations are observed between near-surface wind speed (U10m) and SST and positive correlations between near-surface specific humidity (q2m) and SST. However, when smaller scales (1 – 150km, i.e., encompassing the ocean mesoscale and a portion of the submesoscale) are considered, the U10m-SST and q2m-SST correlate inversely. This is interpreted in terms of an active ocean modifying the near-surface atmospheric state, driving convection, mixing and entrainment of air from the free troposphere into the MABL.The estimated values of the ocean-atmosphere coupling at the ocean small-scale are then used to develop a linear and SST-based downscaling method aiming to include and further investigate the impact of these fine-scale SST features into an available low-resolution latent heat flux (LHF) data set. The results show that they induce a significant increase of LHF (30% - 40% per °C of SST). We identify two mechanisms causing such a large increase of LHF: (1) the thermodynamic contribution that only includes the increase in LHF with larger SSTs associated with the Clausius-Clapeyron dependence of saturating water vapor pressure on SST and (2) the dynamical contribution related to the change in vertical stratification of the MABL as a consequence of SST anomalies. Using different downscaling setups, we conclude that largest contribution comes from the dynamic mode (28% against 5% for the thermodynamic mode). To validate our approach and results, we have implemented a set of high-resolution WRF numerical simulations forced by high-resolution satellite SST that we have analyzed in terms of LHF using the same algorithm.To provide further validation to our results we use the high spatio-temporal resolution of in-situ data collected during the EUREC4A-OA/ATOMIC campaigns that go beyond the coarse spatial grid of available satellite observations and include additional variables to the SST such as the impact of ocean currents and the local vertical stratification of the upper ocean.
Correcting PM2.5 data from low-cost sensors using machine learning techniques
Authors: Agrawal Pratyush , Srishti Srishti , Kulkarni Padmavati , Gautam Hrishikesh , Kushwaha Meenakshi , Vakacherla Sreekanth , Singh Pratima
Published: February 2023

Low-cost sensors (LCSs) used for measuring air quality have become popular because of their portability, affordability, and ease of operation. However, LCS data often have accuracy and bias issues that need to be addressed before using them for research. LCSs are, therefore, collocated with reference-grade instruments, and various statistical and machine learning (ML) approaches are used to correct the observed bias in data. In this study, collocation experiments were conducted in Bengaluru, India, for about nine months (December 2021 to August 2022). We used nine PM2.5 LCSs that were collocated with a beta attenuation monitor (BAM), which is certified by the United States Environmental Protection Agency (USEPA). Hourly averaged data from LCSs and BAM were used to train various ML correction models. The LCSs included in the study—Airveda, Atmos, Prana Air, BlueSky, Aurassure, Aerogram, PurpleAir, and Prkruti—are widely available in the Indian market. The ML models include support vector regression (SVR), decision tree (DT), random forest (RF), and eXtreme gradient boosting (XGBoost). For the LCSs used in the study, a total of 170 ML models were built to identify the best-performing correction model for each sensor. Model performances were evaluated based on the following metrics: mean absolute error (MAE), root mean square error (RMSE), and normalised RMSE (NRMSE). During the study period, the average hourly BAM concentration was ~32 µg/m3. Hourly averaged PM2.5 from LCSs and BAM exhibited a linear relationship. The NRMSE values of the raw (uncorrected) LCSs PM2.5 with respect to BAM PM2.5 varied between 0.26 and 0.89 across various sensors. The Plantower-based LCSs (Atmos I, PurpleAir, and Aerogram) performed better, characterised by the lowest RMSE/NRMSE values. SVR was found to be the best-performing model for most of the sensors in correcting raw LCSs PM2.5 data. The NRMSE of the ML models’ corrected LCSs PM2.5 was reduced by 46% to 74% across various sensors compared to the uncorrected LCSs PM2.5. As a case study, we also added black carbon (BC) data to our ML models, but no significant change (improvement by 6% RMSE) in performance was observed.
Climate response to Atlantic meridional energy transport variations
Authors: Jiang Weimin , Gastineau Guillaume , Codron Francis
Published: February 2023

The climate impacts of fluctuations in the Atlantic meridional overturning circulation (AMOC) are studied using an atmosphere-ocean general circulation model (AOGCM). In two experiments, the baroclinic component of the North Atlantic Ocean currents is modified online to reproduce typical strong and weak AMOC conditions found in a preindustrial control simulation using the same model. These experiments are compared with slab ocean model (SOM) experiments that use heat flux corrections from the coupled model in the Atlantic Ocean. The main impacts of a strong AMOC include widespread warming in the Northern Hemisphere and a northward shift of the intertropical convergence zone (ITCZ). SOM experiments show similar atmospheric responses to AMOC-related heat flux anomalies, but with much larger impacts in the tropics. The atmospheric changes are driven by an anomalous cross-equatorial Hadley circulation transporting energy southward and moisture and heat northward. In the AOGCM, changes in the Indo-Pacific Ocean circulation and heat transport, driven by the wind stress associated with the abnormal Hadley cell, damp the atmospheric response. In the SOM simulations, the lack of Indo-Pacific transport and of ocean heat storage leads to larger atmospheric changes, that are further amplified by a positive tropical low cloud feedback. 
Geodynamic modelling of salt-bearing rifted margins: from minibasin- to margin-scale salt tectonics across different margin types
Authors: Pichel Leonardo , Huismans Ritske , Gawthorpe Rob , Faleide Jan Inge , Theunissen Thomas
Published: February 2023

The largest and majority of salt basins form along rifted continental margins during the latest stages of rifting and prior to continental breakup. We use 2D thermo-mechanical finite-element modelling of lithospheric extension to investigate the interplay between rifted margin architecture, late syn-rift salt deposition, and post-rift salt tectonics across different types of continental margins. We evaluate the: 1) interplay between syn-rift extension, salt deposition and post-rift salt tectonics, 2) influence of salt basin architecture on salt flow, 3) distribution of salt-related structural domains, and 4) contrasting salt tectonic styles for different margin types. Narrow margins form partially-isolated salt sub-basins with prominent base-salt relief, limited translation but significant diapirism and minibasin development. Wide margins form wide salt basins with subtle base-salt relief, pronounced seaward salt expulsion and overburden translation, which result in updip extension with development of post-rift normal faults and rollovers, mid-margin translation and downdip diapir shortening. All margins develop a distal salt nappe that varies in width and complexity. The contrasting styles of diapirism and minibasin geometries as well as basin-scale salt deformation between different margin types are controlled by margin width, base-salt relief, salt thickness and the relative rate of progradation. The results are comparable to several examples of salt-bearing rifted margins worldwide, from minibasin- to margin-scale, and improve our understanding of their dynamics and structural variability.
Crystallographic preferred orientations of talc and chloritoid and implications for seismic anisotropy in subduction zones
Authors: Lee Jungjin , Jung Haemyeong
Published: February 2023

Talc and chloritoid are common metamorphic minerals observed in mafic-ultramafic rocks and/or high-pressure metapelitic rocks comprising subducting slabs. Crystallographic preferred orientations (CPOs) of elastically anisotropic minerals have been known to be important for interpreting seismic anisotropy observed in subduction zones. However, studies on the CPOs of talc and chloritoid have been very limited. In this study, CPOs of talc and chloritoid in garnet-chloritoid-talc schist samples from ultrahigh-pressure Makbal Complex (Tianshan, Kazakhstan-Kyrgyzstan) which has been regarded as a part of subducting slab were measured using SEM/EBSD technique. CPO-induced seismic properties of both talc and chloritoid were analyzed and compared. The results showed that both talc and chloritoid displayed strong CPOs characterized by the [001] axes aligned subnormal to the foliation (see also Lee et al., 2021). CPO-induced seismic properties of polycrystalline talc and chloritoid were calculated and they showed that both P-wave anisotropy (AVp = 5 – 72 %) and high S-wave anisotropy (AVs = 10 – 24 %) of talc and chloritoid were much higher than those of garnet (AVp = 0.4 %, AVs = 0.9 – 1.0 %). In addition, the AVp of polycrystalline talc was much higher than that of polycrystalline chloritoid. Analysis of S-wave delay time and fast-polarization direction based on the modelling study of subduction zone geometry showed that the CPOs of talc and chloritoid induced a long delay time of 0.3 – 0.5 s and trench-parallel polarization direction for high dip-angle subduction, which is consistent with the observation of strong trench-parallel seismic anisotropy in subduction zones. Our results suggest that the strong CPOs of talc and chloritoid would influence trench-parallel seismic anisotropy induced by subducting slab in subduction zones. Lee et al., 2021, Seismic anisotropy in subduction zones: evaluating the role of chloritoid, Frontiers in Earth Science, 9, 1-16.
Moisture limits for grassland soil to avoid structural damage due to machine trafficking
Authors: Lepore Emanuela , Schmidt Olaf , Fenton Owen , Tracy Saoirse , Bondi Giulia , Wall David
Published: February 2023

Soil compaction is one of the primary threats to soil degradation in Europe; however, data to guide grassland farmers on how to avoid traffic induced soil compaction is limited. In grassland systems, soil moisture regimes are measured by daily soil moisture deficit (SMD) values and, when coupled with soil physical indicators could help safeguard the soil physical quality (SPQ). The objective of this study is to investigate how soil physical quality changes across different induced traffic compaction events at targeted SMD. A field study at Johnstown Castle Beef Farm (Wexford, Ireland) investigated the severity of soil physical changes caused by machine trafficking across different targeted soil moisture regimes. A tractor and a fully loaded slurry tanker trafficked moderately drained soil plots at SMD targets of 10 (dry (D)), 0 (moist (M)) and – 10 (wet (W)) mm. Compaction events simulated four passes across one year of grassland management: at the time of the first silage cut, in April; after the first cut silage harvest, in June; before the slurry spreading opening season, in October; and at the beginning of the slurry spreading period, in January. Soil bulk density (BD) samples were taken in the middle of the tyre marks at different depths (0-10, 10-20 and 20-30 cm). To examine indirect soil physical quality of various treatments, soil physical data was used to calculate the S value (Si) using the SawCal model. Initial results showed that the progressive increase in the number of trafficking events occurring above SMD 0 mm  led to major compaction, which significantly increased (P<0.05) compared to trafficking at SMD 10 mm. The cumulative effect of the four passes showed a significant difference from M to D and W, with M’s BD increasing by 22.2% compared to the control. D and W BDs remained similar ranging between 1.10 and 1.11 Mg m-3. Accordingly, Si values were indicative of very poor (i.e. degraded; S < .035) SPQ in M only. These early results indicate that the most severe degradation occurred in the 0 – 10 cm depth. Forecasting soil moisture is a valuable tool for the protection of SPQ and to enable farmers to minimise any soil degradation due to trafficking.Keywords: soil compaction, grasslands, soil moisture, field traffic, soil physical quality indicators
Artificial intelligence and volcanic data management: a dialogue between technique and administration
Authors: Brigante Vinicio
Published: February 2023

For years now, proliferation of technological tools has been taking hold, albeit with some resistance, in the public sector as well, since as reflected in the agendas and public policies of EU member States, digitalization is a non-deferrable need, a prerequisite for the implementation of further reforms. This report’s purpose is to ascertain whether and how, data in IA can support administrations and stakeholders in coping with unforeseen events, such as earthquakes and volcanic eruptions.Among disaster protection risks, volcanic activity is often considered a foreseeable risk because it is thought that phenomena that presage rising magma to surface can be recognized and measured, which is why they are called precursors although this is, however, a simplification that does not take into account the complexity and extreme variability of volcanic phenomena and the difficulty in assessing and interpreting them.Precursor phenomena only as indicators of an ongoing process that if properly and adequately studied, analyzed and monitored, can give an idea of the state of volcano activity and its possible evolutions, allowing for the detection of possible anomalies. For this reason, data and processing by AIs can provide support and decrease errors in the calculation of phenomena even if it could only be a quantitative reduction.Data and their processing can provide a reliable index to support prevention activities. Potential issues for the jurist involve ownership of database management, interoperability, errors in the management of the same knowledge. Grading operated by AI and data has the advantage of being rapid and devoid of operator discretion. Machine learning, in fact, has a capacity of about 98 percent to hit the attribution of a rock of unknown origin.Central node within the discussion is to determine the ownership of data and the AI tools deputed to process them, whether to endow public facilities or outsource this function to the private sector.
Thickness variations in the Kimmeridge Clay Formation in southern and eastern Britain: implications for Late Jurassic basin evolution
Authors: Woods Mark , Burrel Laura , Newell Andrew
Published: February 2023

The Kimmeridge Clay Formation is a mudrock-dominated succession deposited during the Upper Jurassic –Kimmeridgian and Lower Tithonian stages– in a shallow shelf environment, below fair- weather wave base. With a maximum thickness of 712m onshore, and 1400m in the northern North Sea, the formation has several intervals of bituminous shales, rich in organic matter, that make it a major oil source rock in the North Sea.In the Late Jurassic, north-western Europe was part of the Laurasian Seaway, a shallow marine area underlain by a system of interconnected extensional basins. In Britain, sedimentation of the Kimmeridge Clay Formation took place in two main depo-centres; the onshore Wessex and Weald basins and adjacent Channel Basin in southern Britain, and the East Midlands Shelf and adjacent Cleveland Basin in north-eastern Britain, extending offshore into the North Sea. These depo-centres were bounded by normal fault systems. with significant syn-depositional activity associated with  Late Jurassic crustal extension allowing  development of thick sedimentary successions in the hangingwalls of these structures.The sedimentary patterns of the Kimmeridge Clay formation are rhythmic, with intervals of mudstones, organic-rich mudstones and carbonate-rich stone bands, that give characteristic inflection patterns to wireline logs. These patterns are very similar across the Wessex and Weald basins but differ slightly from those of the East Midlands Shelf and Cleveland Basin; perhaps a consequence of compartmentalisation of accommodation space by the Anglo-Brabant Massif.We present a new correlation of borehole geophysical logs (gamma & sonic) and associated thickness maps and structural maps for the Kimmeridge Clay Formation. They reveal lateral changes in thickness that reflect the influence of underlying basin structure on patterns of deposition and post-depositional erosion.
Regional flood frequency in North Africa
Authors: Tramblay Yves , El Khalki El Mahdi , Sadaoui Mahrez , Benaabidate Lahcen , Boulmaiz Tayeb , Boutaghane Hamouda , Dakhlaoui Hamouda , Hanich Lahoucine , Meddi Mohamed , Ludwig Wolfgang , Saidi Mohamed Elmehdi , Mahé Gil
Published: February 2023

The Maghreb countries located in North Africa are strongly impacted by floods, causing extended damage and numerous deaths. Up to now, the lack of accessibility of river discharge data prevented regional studies on potential changes in flood hazards or the development of regional flood frequency estimation methods. A database of daily river discharge data from 55 basins located in Algeria, Morocco and Tunisia, has been recently compiled, with on average 32 years of complete records over the time period 1970-2017. A peaks-over-threshold sampling of flood events is considered, first to detect trends on the annual frequency and the magnitude of floods. The trend analysis results indicated no significant changes in flood frequency nor magnitude, with only a few spurious trends detected in cases of isolated extreme or clustered events. Then, two regional estimation methods for flood quantiles were compared, based either on spatial proximity or catchment characteristics. The regional estimation from multiple catchment characteristics (including soil types, land use, elevation, geology, extracted from global databases) was performed comparing two multiple linear regression methods, Stepwise regression and Lasso regression, and two machine learning algorithms, Random Forests and Support Vector Machines. Results indicate a better performance of the regional estimation of flood quantiles with catchments characteristics than with spatial proximity, with a mean absolute error in cross-validation close to 40%. These encouraging results open the perspective of operational applications of these methods, in particular by increasing the number of basins considered.
Ionospheric scintillations studies using Spire and COSMIC-2 radio occultation and GOLD satellite data
Authors: Mohanty Shradha , Hoque M. Mainul
Published: February 2023

Low-earth orbits (LEO) satellites have been harnessing the concept of GNSS radio occultation (RO) for several atmospheric applications. With the advent of CubeSat technology, many space companies are now extending the GNSS-RO for ionospheric and space weather studies. This study demonstrates the capabilities of Spire’s constellation of CubeSats in detecting ionospheric scintillations. High rate 50 Hz GNSS measurements received by the STRATOS receivers onboard Spires’s CubeSats are used to detect scintillations over low latitude African sector. Spire’s GNSS-RO atmPhs files are accessed from University Corporation for Atmospheric Research (UCAR) data repository along with COSMIC-2 conPhs files.The amplitude scintillation index (S4) is computed for each COSMIC-2 and Spire RO profiles. While COSMIC-2 conPhs files are restricted to tangent point altitudes up to ~130 km, the scintillation detection algorithm onboard Spire receivers enable to downlink the associated 50 Hz phase and pseudorange data of the extended RO profiles (up to zenith). Spire’s extended RO profiles enable to detect F-layer amplitude scintillations often occurring in post-sunset hours. The occurrences of scintillations are corroborated by equatorial plasma bubble (EPB) structures observed from NASA’s Global‐scale Observations of the Limb and Disk (GOLD) satellite.This study indicates the potential of Spire GNSS-RO data in augmenting and complementing ionospheric scintillation studies available from COSMIC-2 and other similar RO missions. This capability can provide an important contribution to scintillation monitoring and can further be extended to space weather nowcasts and forecasts
Jet-like structures in different regions of the magnetosheath
Authors: Goncharov Oleksandr , Šafránková Jana , Němeček Zdeněk , Xirogiannopoulou Niki
Published: February 2023

Plasma structures with the enhanced dynamic pressure, density or speed are often observed in the Earth’s magnetosheath. These structures, known as jets and fast plasmoids, can be registered in the magnetosheath, downstream both the quasi-perpendicular and quasi-parallel bow shocks (BS). Using measurements by the Magnetospheric Multiscale (MMS) spacecraft, Goncharov et al. (2020) showed similarities in the plasma properties of the jets and fast plasmoids. However, they pointed out that the different magnetic fields inside the structures suggest that the formation mechanisms are different. Hybrid simulations by Preisser et al. (2020) have shown differences in the mechanisms of jet and embedded plasmoid formation. On the other hand, structures registered close to the BS/magnetopause or in the sub-solar/flank magnetosheath are not fully the same. Based on our comparative analysis, we discuss features of jet-like structures, their properties, occurrence, evolution, and relation to the magnetosheath parameters.
Non-uniform structures in the solar wind and its interaction with the Earth’s magnetosphere
Authors: Grygorov Kostiantyn , Němeček Zdeněk , Šafránková Jana
Published: February 2023

The solar wind prediction in front of the Earth relies on the spacecraft observations at the L1 point. In the last decade, the Wind and ACE missions orbiting around the L1 point were accompanied with the DSCOVR spacecraft. This configuration allows determination of the spatial structure of solar wind discontinuities that in turn impact the Earth. Processes in the heliospheric current sheet can produce structures with scales comparable to the entire dayside magnetosphere and such structures can be misinterpreted using OMNI data that are based on observations in one point only. In this study, we present the tracing of such inhomogeneous structures in the solar wind from L1 toward the Earth. We analyze in details their manifestation in the magnetosheath, at the magnetopause and inside the magnetosphere with motivation to more precisely determine the shape and location of magnetospheric boundaries. Moreover, we investigate the mechanisms leading to creation and development of such structures in the solar wind.
Integrating cover crops with no-tillage benefits crop yields, increases soil carbon storage while reducing nitrogen leaching in global croplands
Authors: Ma Jianyong , Anthoni Peter , Olin Stefan , Rabin Sam , Bayer Anita , Arneth Almut
Published: February 2023

Increasing crop productivity while keeping detrimental side-effects on the environment low is a major challenge for global agriculture. Cover crops (CCs), mostly grown during the fallow period and incorporated in soils, are expected to improve soil fertility and crop yields while reducing chemical fertilizer use, with climate change mitigation co-benefits. However, quantifying these ecosystem services across global agricultural lands remains uncertain. In this study we investigate how the use of herbaceous CCs with and without biological nitrogen (N) fixation affects yields and cropland carbon and nitrogen balances using the dynamic global vegetation model LPJ-GUESS. Model performance is evaluated against observations from field trials worldwide as well as other published model-based estimates. LPJ-GUESS generally captures the observed enhanced soil carbon, reduced N leaching, and yield changes caused by CCs. We found that the combination of N-fixing CCs with no-tillage management could potentially increase soil carbon storage by 7% (+0.32 Pg C yr-1 in global croplands) while reducing N leaching by 41% (-7.3 Tg N yr-1) compared with bare fallows after 36 years of simulation. This integrated practice is accompanied by a 2% increase in total crop production (+37 million tonnes yr-1 including wheat, maize, rice, and soybean) in the last decade of the simulation. Legume cover cropping is found to contribute more to increasing the subsequent crop yields than non-legumes. The effects of CCs on crop productivity are highly dependent on the main food crop types, chemical fertilizer use, and management duration, with smallest yield changes found in soybean systems and highly fertilized agricultural soils. Our results demonstrate the possibility of conservation agriculture when targeting long-term environmental sustainability without compromising crop production in global croplands.
Numerical investigation of the failure of the colluvium slope with retaining piles induced by rockslides
Authors: Wei Ting-Syuan , Lin Cheng-Han , Lin Ming-Lang
Published: February 2023

Retaining piles is the common mitigation measure for stabilizing colluvium slopes due to ease of design and cost-efficiency. Although there are many successful applications of retaining piles in Taiwan, several cases failed due to lack of consideration in design stage. We focused on a specific case in the downstream of Chiaohu River, central Taiwan. Remote-sensing analysis shows that this site has collapsed at least five times since 1948 and the rockslides from source area of colluvium dominate the stability of colluvium. The latest colluvium failure that occurred in 2019 had damaged the retaining piles. The design report of the retaining piles reveals that the stability analysis only considered the colluvium as the acting force. In the scenario, limit equilibrium method can be used to evaluate the factor of safety of the colluvium slope with piles. However, the limit equilibrium method is not applicable when the colluvium slope failed because the rockslide at the upper slope. This study aims to provide insight into the complex behavior of rockslide-induced colluvium slope failure and the stability of retaining pile in context of this design factor, facilitating the development of a numerical model. We first conducted geological investigations and remote sensing analysis to understand the evolution of landslide history. Next, three-dimensional full-scale numerical model was built based on coupled FDM-DEM technique. DEM was used to simulate the rockslide source and colluvium material, and FDM was used to model the piles in the colluvium. The back-analysis shows that simplified consideration of only colluvium material on the stability of retaining piles underestimate the effects of sliding force of the rockslide on behavior. In addition, the rockslides not only increase total landslide volume, but also are the source of the colluvium deposit in landslide history. This study demonstrates that the assessment of the stability of the colluvium slope with retaining piles induced by rockslides can be aided by using coupled FDM-DEM simulation.
Influence of dam failure flow on water level in dam and the underwater breach topography
Authors: Chiu Kai-Yi , Chen Su-Chin
Published: February 2023

Due to the young geology, unique climates, and location in the Pacific Rim seismic zone, complex sediment disasters frequently occur in Taiwan.  After the Chi-Chi earthquake in 1999, more than ten landslide dams appeared in the mountain regions with disaster potential to the neighbor.  The process of landslide dam breach is complex, often accompanied by abundant sediment and floods that cause damage to the downstream environment.  Therefore, analyzing the landslide dam breach process is an important subject.The study area is located in Landau Creek in Huisun Forest, Nantou County.  Landao Creek is a tributary of the Beigang River, a potential debris flow torrent.  The soil and rocks on site were used to build a natural dam for the dam failure experiment.  The process of dam failure was recorded with cameras and UAVs.  In order to understand the relationships between the dam and the water level, some water pressure gages were set inside the dam and in upstream to measure the water pressure over time.  Because it is difficult to observe the change of the underwater breach with the naked eye during the dam failure process, triaxial sensors were placed in the dam body to determine the change of dam breach by recording the time when the sensors were scoured away from their original position.  The analysis showed that the groundwater level gradually increased during the dam failure, and the downward trend would slow down over time.  The underwater breach shape was similar to a parabolic or trapezoid shape.
The perfect storm? Concurrent climate extremes in East Africa
Authors: Muheki Derrick , Deijns Axel , Bevacqua Emanuele , Messori Gabriele , Zscheischler Jakob , Thiery Wim
Published: February 2023

Concurrent extreme events exacerbate adverse impacts on humans, economy, and environment relative to those from independent extreme events. However, while the effects of climate change on the frequency of individual extreme events have been highly researched, the impacts of climate change on the interaction, dependence and joint occurrence of these extremes have not been extensively investigated, particularly in the East African region. Here, we investigate the joint occurrence of six categories of extreme events in East Africa, namely: river floods, droughts, heatwaves, crop failures, wildfires and tropical cyclones using bias-adjusted impact simulations under past and future climate conditions. We show that the change in the probability of joint occurrence of these extreme events in the region can be explained by the effects of climate change on the frequency, spatial distribution, and dependence of these extreme events. The analysis demonstrates that there is a higher positive correlation between most co-occurring pairs of extremes in the region under end-of-century global warming conditions leading to more frequent concurrence in comparison to the early-industrial period. Our results further highlight the most affected locations in the region by these concurrent events and consequently the main driver(s) in the various co-occurring pairs of extremes. Our results overall highlight that concurrent extremes will become the norm rather than the exception in East Africa under low-end warming scenarios.
Dynamics of Campi Flegrei caldera (Italy) after the 1538 AD eruption
Authors: Magri Carmine , Trasatti Elisa , Acocella Valerio , Del Gaudio Carlo , Ricco Ciro , Di Vito Mauro Antonio
Published: February 2023

Understanding how shallow magma transfer occurs at volcanoes is important to have a conceptual model of how a volcano works and, possibly, to forecast where and when an eruptive vent may open. However, shallow magma transfer is difficult to detect at poorly monitored volcanoes, and particularly at calderas, characterized by areal volcanism. Magma transfer before the last 1538 eruption at Campi Flegrei caldera (Italy) was previously studied using historical, archaeological, and geological data. Here, we extend that dataset to 1650, to uncover any magma transfer during overall post-eruptive phase. Results highlight two post-eruptive subsidence phases, separated by a previously undocumented uplift during 1540-1582. Uplift highlights the pressurization of the central (~3.5 km depth) and peripheral (~1 km depth) pre-eruptive sources, suggesting an aborted eruption. The subsidence events are explained by the depressurization of the central source and pressurization of a deeper magmatic layer (~8 km depth). Therefore, despite the overall post-eruptive deflation, after 1538 the deeper reservoir experienced continuous magma supply, with magma almost erupting between 1540-1582, challenging the common assumption of post-eruptive relaxation. This underlies the importance of monitoring the deeper magmatic systems, also after eruptions, to properly assess their eruptive potential.
Building an agent-based model to explore the interactions between human activities and vegetation cover on sandy anthropogenic shores (SAS) in the Netherlands
Authors: Bakhshianlamouki Elham , Augustijn Ellen-Wien , Wijnberg Kathelijne , Voinov Alexey , Brugnach Marcela
Published: February 2023

AbstractCoastal dunes play an essential role in defence against the sea in many countries, including the Netherlands. Sandy Anthropogenic Shores (SAS) is the recent nature-based human intervention for dune reinforcement. SAS are coastal zones (including shores, dunes, lagoons, etc.) that are created or heavily modified by moving large amounts of dredged sand from offshore to near the coast. This allows natural processes (waves, winds, and currents) to spread the sand and reinforce the foredune for longer-term coastal safety. Not only the natural processes but also vegetation cover near the dune foot and on the foredune play essential roles in trapping windblown sand from the coast, steering embryo dune development and dune growth. The Sand Motor and Hondsbossche Dunes are two examples of SAS in the Netherlands. Previous studies of vegetation on SAS have mainly assessed the influence of natural conditions such as climate change, nutrient availability, sand burial, beach shape (morphology and width), hydrodynamic wave characteristics, etc., on vegetation propagation. The impacts of short-term human management of the coast and recreational activities still need to be addressed. We chose an agent-based model (ABM) approach to simulate human activities, including management and use of SAS and coupled it with a biophysical model similar to DUBEVEG. DUBEVEG is a biophysical model simulating the interactions between natural processes caused by wind, wave and tide, vegetation cover, and beach-dune sediment dynamics. We conducted several interviews and workshops with stakeholders from the management sectors. We also surveyed the beach users to elicit knowledge about social dynamics and their interaction with the biophysical system (morphology and vegetation). Using NetLogo, we developed an ABM, translating the elicited knowledge into a quantitative model. The developed ABM was used to analyse how various landscape designs of the modified coast (e.g., types and locations of recreational facilities such as restaurants, beach houses, artificial lagoons, entrances, car parking, etc.) influence human activities. Then, we used the model to explore the impact of human dynamics on vegetation growth and embryo dune development in the long term. The developed ABM model improves the sustainable design and management of the SAS by exploring the influence of SAS's initial design and short-term decisions about recreational activities and flood safety measures on the long-term evolution of the landscape (vegetation and morphology).
Hunting for heat pulses: streamwater temperature responses to summer storms as tracer for urban water sources
Authors: Knapp Julia , Kelleher Christa
Published: February 2023

Streamwater temperature is an important water quality parameter, and controls metabolic and other reaction processes. In urban systems, streamwater temperature has been shown to depend substantially on the near-stream land cover: Riparian buffer zones may cool urban streams, while effluent from wastewater treatment plants is known to raise streamwater temperatures. Groundwater contributions can decrease summer and increase winter streamwater temperature, essentially acting as a temperature buffer. In consequence, streamwater temperature is highly dependent on the specific layout of the urban system.Streamwater temperature fluctuates on annual, seasonal, daily, and diurnal basis, however, storm events may additionally impact streamwater temperature on short time scales. The timing and patterns of streamwater temperature responses to storm events relative to the hydrograph may differ from event to event. Because urban infrastructure is typically designed to rapidly route water to the sewer network to avoid flooding, streamwater temperature response patterns are likely related to event- and site-specific water sources contributing to streamflow. Changes in temperature patterns could thus be linked to changes in water release processes. If we disentangle the various empirical relationships revealing potential physical controls on how water is conveyed to streams in urban areas, temperature could potentially be used as a cheap tracer of water sources and pathways in urban systems, which are typically difficult to assess.We investigated and quantified different streamwater temperature response patterns to stormflow, to understand predictors of diverse streamwater temperature responses to summer storms. We found that streamwater temperature shows varied response patterns to storms, including temperature increases and decreases. Some of the temperature increases may take the shape of rapid “heat pulses”, a short but relatively high magnitude temperature increase and subsequent drop at the start of the hydrograph. Streamwater temperature responses to storms were event-specific and could be clearly linked to event characteristics. Understanding the streamwater temperature response can thus aid in understanding urban source contributions to streamflow, because the mixing of sources – and the timing of this mixing process – causes a unique streamwater temperature pattern. Likely sources contributing to the streamwater temperature patterns are ponded surface waters and storm drains, or cooler water from the shallow subsurface. These findings indicate that streamwater temperature may be used as a cheap but effective tracer informing the contributions from different source zones in urban catchments.
Spatio-temporal variability of air temperature lapse rate in the glacierised catchment of the Chandra basin, western Himalaya using in-situ measurements
Authors: Oulkar Sunil N. , Sharma Parmanand , Pratap Bhanu , Patel Lavkush , Laha Sourav , Thamban Meloth
Published: February 2023

The air temperature lapse rate (TLR) plays an important role in estimating ice and snow melt in high mountain regions. The TLR can vary depending on several factors, including the topography of the catchments and the microclimate. TLR calculations are typically not precise in the Himalayan glacierised regions due to a lack of in-situ observation of meteorological parameters. Therefore, a dense in-situ monitoring network over a high altitudinal gradient is needed to estimate the TLR accurately. We have obtained in-situ measurements of air temperature data from five automatic weather stations (AWS) installed at the best possible locations in the Chandra basin catchment of the semi-arid zone of the western Himalaya from October 2019 to September 2022. The altitudinal range for air temperature measurement varied between ~4000 and 5000 m a.s.l. We utilise the air temperature data to estimate the TLR by regressing the temperature with the corresponding elevations.Comparing all the estimated TLR, the mean annual value (4.9°C/km) was significantly lower than the standard environmental lapse rate (6.5 °C/km) with substantial seasonality. The maximum TLR (~6.8 °C/km) during the summer is likely due to the high-altitude range and thin air and the presence of cold air pools at higher altitudes. However, the significantly lower TLR (~1.9 °C/km) during winters is likely due to the low air temperature and high moisture content in the region due to western disturbance. Further, we observed strong diurnal variations of TLR, which was highest during the daytime and lowest at night. This study highlighted that the TLR was potentially influenced by the local topography, particularly with higher lapse rates at higher elevations. TLR vary topographically and temporally significantly in the Chandra basin, indicating that the air temperature in this region is more sensitive to climatic variations. The findings of this study will play an important role in glacio-hydrological models, where TLR is one of the essential inputs.
Climate Analogs Analysis over Europe: Accounting for dependencies between variables
Authors: Bulut Burak , Vrac Mathieu , de Noblet-Ducoudré Nathalie
Published: February 2023

Increasing the awareness of society about climate change by using a simplified way for the explanation of its impacts might be one of the key elements to adaptation and mitigation of its possible effects. This study investigates climate analogs, which allow a comparison between current and future climate conditions. The grid-based calculation of analogs over the selected European domain was carried out using a newly proposed distance between multivariate distributions, the Wasserstein Distance (WD), never been used so far for climate analog calculations. By working on the whole multivariate distributions, WD allows us to account for dependencies between the variables of interest. Its features are compared with the Euclidean Distance which is currently the most used method. Multi-model climate analogs analysis is achieved between the reference period 1981-2010 and three future periods 2011-2040, 2041-2070, and 2071-2100, respectively by using 15 different datasets in total obtained from five different CMIP6 climate models and three different emission scenarios. The multi-model analysis also enables the comparison of models from a climate analogs perspective. The model comparison results show that consistency between models decreases as the time approaches the end of the century or when scenarios worsen. Our analysis suggests that Europe’s future analogs are located today south of our regions, except for the Balkans that need to look east to find their analogs. In addition, towards the end of the century, the similarity between future and current climatic conditions will gradually decrease and the spatial distance between each reference grid and its best analog location will increase. This means that the warmer the climate, the more difficult it will be to find an analog and therefore the more difficult it will be for us to think about adaptation.