bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactive transport modelling reveals changes in properties of tropical soils subjected to enhanced silicate weathering
Authors: Glorieux Juliette , Goddéris Yves , Kuppel Sylvain , Delmelle Pierre
Published: March 2024

Applied regionally to cropland soils, enhanced silicate weathering (ESW) is advocated as a viable technology for enhancing the consumption of atmospheric CO2, while also providing ancillary benefits to soil fertility and crop growth. However, important uncertainties remain regarding the short- and long-term effects of silicate addition on weathering rate and soil properties. To address this issue, we adapted and used the reactive transport model WITCH1 to simulate weathering in a tropical soil (Oxisol) amended annually with 50 t ha-1 of crushed basalt over five years. We monitored the changes in the soil chemical properties, primary and secondary mineralogy and CO2 consumption rate over a 10-year period. The modelling results confirm that the instantaneous CO2 consumption rate increases with basalt application. Basalt weathering increases the pH of the soil solution, from acidic to alkaline values, and releases Ca, Mg and K in solution, thus serving as a plant nutrient source. We also found that allophanes may form in the Oxisol in response to dissolution of the basalt’s glass and plagioclases. As evidenced in volcanic soils, allophanes typically exhibit a significant potential for organic carbon stabilisation. The formation of allophanes in the Oxisol treated with basalt may improve aggregation processes, water retention and hydraulic conductivity, but may decrease phosphate availability further. Our modelling study highlights that the intentional application of basalt to a tropical soil affects various soil properties significantly. The short and long-term impacts of these changes on soil functioning will need to be assessed.1Goddéris et al., 2006. GCA 70:1128-1147
AlpIce - Towards an Alps-wide database of empirical geo(morpho)logical and geochronological data constraining Last Glacial Maximum to Holocene glacier fluctuations
Authors: Kamleitner Sarah , Leger Tancrède P. M. , Ivy-Ochs Susan , Nussbaumer Samuel U. , Vieli Andreas , Jouvet Guillaume
Published: March 2024

Latest advances in numerical modelling using machine learning sped-up glacier models by several orders of magnitude, thus facilitating glacier evolution models to run at high resolutions (hundreds of metres) over timescales of several tens of millennia and over mountain range scales. The RECONCILE project seeks to use the Instructed Glacier Model (IGM) to simulate the maximum state and deglaciation of the last glaciation of the European Alps and to test model output against the geological record. A robust framework against which to test Alps-wide and transient paleoglacier model simulations is however missing. Despite the long history of Quaternary research in the Alps and abundant publications on the topic, the integration of field evidence for model validation has thus far largely been restricted to the Last Glacial Maximum (LGM) ice extent. Inspired by work on the (former) British, Fennoscandian, Patagonian and Greenland ice sheets, we aim to build a comprehensive and standardized dataset on paleoglacier variations for the European Alps. Coupling geo(morpho)logical data and geochronological markers, the AlpIce database will act as an empirical basis for future quantitative model-data comparisons. Published empirical evidence that restrains the build-up, culmination, and disintegration of the Alpine LGM glaciers as well as subsequent Alpine Lateglacial and Holocene glacier advances are considered. Relevant surface exposure and radiocarbon datings are currently gathered and fed into the database. Data reliability assessments and paleoglaciological context classifications are undertaken concurrently. The database structure also allows the inclusion of additional chronological methods (e.g. luminescence dating, dendrochronology, archeological and historical sources) into AlpIce. Where applicable, the chronological constraints will be linked to related geo(morpho)logical features (e.g. former ice margins, trimlines) using GIS software. AlpIce is designed as an open-access resource hoping to prove useful for both empirical and modelling communities and beyond the scope of model validation.
An improved biodiversity index for FAO’s Tool of Agroecology Performance Evaluation (TAPE)
Authors: Baumgartner Simon , Gilgen Anina , Felder Rahel , Herzog Felix , Jeanneret Philippe , Séchaud Robin , Paunovic Stevan , Lucatoni Dario , Cluset Remi , Mottet Anne , Merbold Lutz
Published: March 2024

The "Tool for Agroecology Performance Evaluation" (TAPE) was developed under the coordination of the Food and Agriculture Organisation of the United Nations (FAO) to assess the sustainability performance of agroecosystems. The assessment is mainly based on a 2-3-hour farm interview, in which a wide variety of data is collected. The environmental dimension has so far been represented in TAPE by two simple indices: A soil index, which is based on a visual analysis of the soil, and a biodiversity index, which is primarily based on the Gini-Simpson index of crops grown and animals kept. While the TAPE biodiversity index is crucial, it does not yet take into account so-called unplanned biodiversity, i.e. the impact of on-farm management practices on wild species. We have therefore expanded TAPE to include this aspect.Direct surveys of wildlife biodiversity in the field were not possible in TAPE, as this would have far exceeded the time required for data collection. Consequently, we based the newly developed biodiversity index on the indirect European BioBio method. The new index consists of ten indicators, which can take values between 0 and 100% and be aggregated to form the overall index. Examples of these indicators are field size, nitrogen application or stocking density. The new index was developed and tested on selected Swiss farms, where the comparison with a much more comprehensive and time-consuming method showed a positive correlation (r = 0.56, p-value = 0.009).The new index has so far been used in Switzerland (21 farms) and in Kenya (103 farms). In Switzerland, the field size and land use change indicators performed best (values > 75%), while the indicators tree habitat, nitrogen application, field operations and grazing intensity performed poorly (values > 50%). In Kenya, the field size, land use change, pesticide and field operations indicators reached values above 75%, while the tree habitat, grazing intensity and semi-natural habitat indicators had values clearly below 50%.
Projected shifts and dynamics in blue and green water resources availability 
Authors: Heselschwerdt Simon P. , Greve Peter
Published: March 2024

A deep understanding of the dynamics of green and blue water resources is crucial for accurately estimating future water availability. Although projections of precipitation trends are robust in many regions, changes in precipitation partitioning into green and blue water fluxes present a significant source of uncertainty for water management. To quantify water partitioning dynamics, we introduce the Blue-Green Water Share (BGWS) metric. This metric utilizes monthly precipitation data, while monthly runoff and transpiration data are used as proxies of blue and green water fluxes. We investigate the output of fourteen CMIP6 models for the historical period and three Shared Socioeconomic Pathways to assess the scenario dependency of the BGWS changes. Most importantly, we examine how and why the BGWS varies across different regions. Additionally, primary drivers of the BGWS changes are identified by applying a multivariable regression analysis and computing the permutation importance of selected ecohydrological variables.The results illustrate a strong regional dependency and interplay of the driving variables. However, clustering the variable importance demonstrates that BGWS changes in higher latitudes tend to be more dependent on temperature, while precipitation patterns dominate partitioning changes in the tropics. Several regions, including the Mediterranean, Northern South America, and Eastern Australia, show a substantial influence of vegetation alterations on the BGWS change, shifting the partitioning imbalance towards more green water flux. We discuss the varying variable importance based on the counteracting mechanisms of increased CO2 concentrations, altered growing seasons, and changed precipitation patterns. Our results highlight the importance of comprehensively understanding green and blue water dynamics in the context of water resources availability under a changing climate.
Distribution and characteristics of subsurface eddies in the Aleutian Basin, Bering Sea
Authors: Zhang Kun , Song Haibin , Meng Linghan
Published: March 2024

The subarctic Bering Sea, situated between the Pacific Ocean and Arctic Ocean, stands as one of the world's most productive oceanic regions. While the role of oceanic eddies in material transport and energy transfer has been extensively studied, surface eddies have dominated these investigations owing to advancements in remote sensing technology. Recently, attention has shifted to subsurface eddies for their influence on enhancing oceanic mixing. However, challenges persist in delineating the distribution and characteristics of subsurface eddies in the Bering Sea due to the limited effectiveness of satellite methods and the scarcity of field observation.Multichannel seismic (MCS) data can provide high-resolution acoustic images of subsurface thermohaline fine structures, known as seismic oceanography. In this study, we integrate MCS with concurrent vessel-mounted Acoustic Doppler Current Profiles (vmADCP), expendable bathythermograph (XBT), and expendable Conductivity Temperature Depth (XCTD) data collected during cruise MGL1111, along with Argo and Copernicus Marine Service Global Ocean Physics Reanalysis data to investigate the distribution and characteristics of subsurface eddies in the Aleutian Basin.The results underscore the presence of 44 subsurface eddies in the Aleutian Basin, primarily submesoscale with diameters averaging around 20 km. Eddy thickness spans 71.14 - 416.57 m, with eddy core depths ranging from 69.96 - 657.24 m, predominantly concentrated in the 100 - 200 m depth range; only 5 eddies exhibit core depths below 300 m. The cumulative volume of these eddies reaches approximately 434.38 × 109 m3, with the majority exhibiting anticyclonic characteristics, as corroborated by concurrent ADCP data. Analysis of historical CTD data, along with concurrent XBT and XCTD data from cruise MGL1111, delineates distinct water masses—Bering Sea Upper Water (BUW), Bering Sea Intermediate Water (BIW), and Bering Sea Deep Water (BDW)—in the study area. Most identified eddies are characterized as cold core, facilitating the transport of BIW. Trajectory assessments, incorporating concurrent Argo and Copernicus Marine Service Global Ocean Physics Reanalysis data, suggest an eastern and southern origin for these eddies, predominantly propagating westward. Assuming a propagating velocity of 1 cm/s, the estimated total transport of these eddies is approximately 1.76 Sv.We believe that these findings will contribute essential insights to the fields of marine ecology, and climate studies, enhancing our knowledge of ocean dynamics in this critical region.
High time resolution mapping of polar ionospheric flows with the SuperDARN Borealis systems
Authors: Billett Daniel , Rohel Remington , McWilliams Kathryn , Martin Carley , Laundal Karl , Reistad Jone
Published: March 2024

Over the last few years, the five SuperDARN HF ionospheric radars operated by the University of Saskatchewan have been upgraded to digital systems that utilise the flexibility and reliability of software defined radios (SDRs). SDRs allow for a vastly greater control of radar transmit and receive operations, bringing with them new capabilities for scientific experiments that were previously not feasible on analogue hardware. This next generation of SuperDARN radar is named Borealis.  One new radar operating mode implemented at the Borealis radars has been full field-of-view imaging. On traditional SuperDARN radars, one full scan of an entire field-of-view (an area encompassing thousands of kilometres at F-region ionospheric altitudes) takes approximately 1 minute as each of the 16 beam directions is sequentially integrated over. With Borealis, every beam direction can be probed (or “imaged”) simultaneously, providing a 16-fold improvement in scan temporal resolution to 3.5 seconds. We present a new ionospheric data product derived from Borealis imaging mode data: high time resolution mapping of polar E x B drifts. In contrast to traditional SuperDARN ionospheric convection patterns which are nominally derived every two minutes on a coarse global grid, Borealis convection patterns are derived locally over the Canadian polar cap every few seconds. This not only provides the opportunity to study mesoscale ionospheric phenomena like polar cap patches, flow channels, and substorms, but also allows for doing so at a temporal resolution not previously possible without compromising spatial coverage.
The Culprit of Bias in the Shaw-type Method of Estimating Geomagnetic Paleointensity and an Innovative Computational Method for Enhanced Reliability
Authors: Qi Kaixian , Cai Shuhui , Qin Huafeng , Deng Chenglong , Pan Yongxin , Yamamoto Yuhji , Cheng Xin , Wu Hanning , Zhu Rixiang
Published: March 2024

Retrieving precise information about the ancient geomagnetic field strength (paleointensity) is crucial for understanding the Earth's interior evolution. The Shaw-type method is one of the major protocols used to estimate paleointensity, characterized by relatively expeditious processes and high success rates. However, albeit employing strict selection criteria, Shaw-type paleointensity results occasionally exhibit bias, necessitating further methodological development. Despite the significance of identifying the causes of these biased estimates, there has been limited detailed discussion on this issue.To clarify the culprit of bias in Shaw-type paleointensity, we conducted a pseudo-Tsunakawa-Shaw experiment using Permian basalts from the Tarim large igneous province (TLIP). In this experiment, the "NRMs (natural remanent magnetizations)" of the samples were acquired in a controlled lab field. We then monitored changes in various rock magnetic parameters, such as squareness (Mrs/Ms), coercivity (Bc), ARM, amtLTD (amount of remanence demagnetized by low-temperature treatment), MDF (median destructive field), and R (the ratio of thermal remanent magnetization (TRM) to anhysteretic remanent magnetization (ARM)), before and after heating, and compared them to the recovered paleointensities.Our analysis uncover a proportional relationship between changes in R and the bias in paleointensity, likely attributed to variations in grain sizes. Combining with microscopic observations, we further reveal samples with particular magnetic grain sizes (~200 nm) are more prone to alteration in the integral TRM/ARM efficiency during heating. Building on these findings, we propose an innovative computational method exploiting the linear regression of R with various cut-off coercivity intervals for Shaw-type paleointensities (LoRA-Shaw), which yield accurate results in both laboratory-tested and modern lava samples. We also invoke curve fits for samples with “folding” phenomenon which are not suitable for linear regression. The LoRA-Shaw method combined with curve fits may help in mitigating bias from the thermal alteration and multi-domain effect in paleointensity study, and enhance the success rate in paleointensity determinations for constraining geomagnetic field evolution.
Increased belowground tree carbon allocation in a mature mixed forest in a dry versus a wet year
Authors: Rog Ido , Hilman Boaz , Fox Hagar , Yalin David , Qubaja Rafat , Klein Tamir
Published: March 2024

Tree species differ in their carbon (C) allocation strategies during environmental change. Disentangling species-specific strategies and contribution to the C balance of mixed forests, requires observations at the individual tree-level. We measured a complete set of C pools and fluxes at the tree-level in five tree species, conifers and broadleaves, co-existing in a mature evergreen mixed Mediterranean forest. Our study period included a drought year, followed by an above-average wet year, offering an opportunity to test the effect of water-availability on tree C allocation. We found that in comparison to the wet year, C uptake was lower in the dry year, C use was the same, and allocation to belowground sinks was higher. Among the five major C sinks, respiration was the largest (~60%), while root exudation (~10%) and reproduction (~2%) were those which increased the most in the dry year. Most trees relied on stored starch for maintaining a stable soluble sugars balance, but no significant differences were detected in aboveground storage between dry and wet years. The detailed tree-level analysis of nonstructural carbohydrates and δ13C dynamics suggest interspecific differences in C allocation among fluxes and tissues, specifically in response to the varying water availability. Overall, our findings shed light on mixed forest physiological responses to drought, an increasing phenomenon under the ongoing climate change.
Leveraging deterministic weather forecasts for in-situ probabilistic predictions via deep learning
Authors: Landry David , Charantonis Anastase , Monteleoni Claire
Published: March 2024

We propose a neural network approach to produce probabilistic weather forecasts from a deterministic numerical weather prediction. The developed method is applicable to any gridded forecast including the recent machine learning weather prediction model outputs. To postprocess multiple lead times using a single model, we introduce a lead time embedding that encodes the shift in biases as the forecast progresses. We apply our approach to operational outputs from the Global Deterministic Prediction System up to ten-day lead times. The model is trained to predict METAR in-situ surface temperature observations in Canada and the United States. The resulting forecasts have a mean CRPS below 2.5 K at 10 days lead time while maintaining a spread-error ratio of approximately 0.9, suggesting appropriate calibration. For extreme temperatures, the model’s biases are comparable to that of the underlying deterministic forecast. Our approach increases the utility of a deterministic forecast by adding information about the uncertainty, without incurring the cost of simulating multiple trajectories. It requires no information regarding forecast spread and can be used to generate probabilistic predictions from any deterministic forecast.
Ambient noise tomography for geothermal exploration: the central Vienna basin, Austria
Authors: Estève Clément , Lu Yang , Bokelmann Götz , Gosselin Jeremy
Published: March 2024

The Vienna Basin (VB) is currently the main target area for deep geothermal exploration in Austria. Knowledge of the subsurface heavily relies on active seismic reflection that are expensive and logistically demanding. Affordable geophysical prospecting methods are needed to reduce subsurface uncertainty. Over the recent years, seismic ambient noise tomography (ANT) has proven to be a cost-effective and environment-friendly exploration technique. Here, we present an ANT of the central Vienna Basin revealing the shear-wave velocity structure of the top 5 km beneath the surface. We deployed an array of ~100 seismic nodal instruments during 6 weeks over summer 2023. We measured fundamental-mode Rayleigh and Love-wave group velocity dispersion from seismic ambient noise and employed transdimensional Bayesian tomography to invert for isotropic group velocity maps at periods ranging from 0.8 to 5.5 s. We then extracted Rayleigh and Love group velocity dispersion curves from the group velocity maps at all locations and jointly inverted them for shear-wave velocity as a function of depth using a transdimensional Bayesian framework. We discuss features observed in our 3D shear-wave velocity model relevant to geothermal exploration.
Smartphone PPP with the Galileo High Accuracy Service
Authors: Wareyka-Glaner Marcus Franz , Möller Gregor
Published: March 2024

With the release of Android 7.0 in 2016, it became possible to retrieve raw GNSS measurement data from Android smartphones. The capability of directly accessing the GNSS measurements allows, among other things, a more reliable estimation of the user’s position by applying external correction data and sophisticated algorithms. However, the GNSS hardware in smartphones is simple and cost-effective, clearly impacting the quality of the measurements. This results in higher levels of noise and frequently occurring effects like outliers, cycle slips, and multipath.Precise Point Positioning (PPP) is an excellent technique for smartphone positioning due to its features and flexibility. PPP is characterized by applying precise satellite products (orbits, clocks, and biases) and complex models and algorithms to estimate the user's position. Due to this concept, PPP does not require nearby reference stations because these precise satellite products are globally valid. Furthermore, the concept of PPP allows the development of resilient and flexible algorithms, providing a remarkable advantage considering the challenging nature of GNSS measurements from smartphones.The Galileo High Accuracy Service (HAS) started its service in January 2023. This service is free of charge and provides real-time corrections to the broadcasted navigation message for GPS and Galileo over signal-in-space (E6 frequency) and the internet. The design of the Galileo HAS makes it particularly interesting for low-cost GNSS and smartphone applications. According to the system operator, the Galileo HAS enables position accuracies at the decimeter level, depending on the PPP processing algorithms and the GNSS hardware of the user.This contribution addresses challenges originating from the ultra-low-cost smartphone equipment and suggests suitable solutions (e.g., data-cleaning algorithms). Furthermore, PPP results with state-of-the-art smartphones (e.g., Google Pixel 7) and the Galileo HAS are presented. The corresponding PPP calculations are performed with our open-source software raPPPid using the uncombined PPP model with ionospheric constraint in quasi-real-time settings. The results demonstrate that it is possible to achieve position accuracies down to the decimeter level with the Galileo HAS under good conditions.
The trend of gravel bars' degradation in the last two decades is perceived positively by society
Authors: Holušová Adriana , Galia Tomáš , Poledniková Zuzana , Vaverka Lukáš
Published: March 2024

River management and regulations can significantly impact the dynamic nature of gravel bars in rivers. The aim of this research is to identify changes in gravel bar morphodynamics including vegetation cover succession in three Czech rivers: the Odra and two of its tributaries. The spatiotemporal analysis focuses on the most recent years 2000-2020 and compares them with historical conditions (1937-1994 in the Odra and from the 1950s in the Olše and Ostravice). Additionally, we aimed to determine how society perceives gravel bars as features in river channels. We analysed gravel bar spatiotemporal morphodynamics using orthophotos and associated hydrological data. The survey of public perception included two sets of photographs depicting regulated and natural environments at different stages of vegetation growth, and assessed perceptions of naturalness, recreation, aesthetics, and vegetation.The historical state of gravel bars showed naturally dynamic gravel bars with great variability of vegetation cover throughout the years. However, the recent period has demonstrated an increasing trend in vegetation cover with disruptions following the 2010 and 2014 floods and leading to temporary decreases of vegetation, notably in the two gravel-bed tributaries. The meandering Odra river conversely exhibited an uninterrupted upward trend. Additionally, the regulated sections of the Odra featured significantly less gravel bar area compared to natural sections. In the public survey, 239 respondents expressed a preference for gravel bars in natural river section. They particularly preferred those with abundant vegetation cover, across all assessed criteria. Unvegetated gravel bars were indicated to be preferable if they were either vegetated or removed from the river channel. Our research emphasizes the unfavourable viewpoint of society towards gravel bars with limited or no vegetation and preference of highly vegetated bars that is a direct reflection of recent trend toward a substantial increase in vegetation-covered gravel bars or loss of gravel bars. These findings highlight the loss or degradation of ecologically valuable habitats and society's misconception about gravel bars, which may affect future conservation efforts of these features.
Cambrian waptiid euarthropod Chuandianella from the Chengjiang biota
Authors: Liu Cong , Fu Dongjing , Zhang Xingliang
Published: March 2024

Chuandianella ovata, a waptiid “bivalved” arthropod occurred in strara of Cambrian Series 2 and Stage 3 (ca. 521–514.5 Ma) along the western margin of the Yangtze plate, has been reported in numerous publications, whereas many morphological features still require further investigation. Herein, based on 1459 finely preserved specimens from eight localities of the Chengjiang biota, seventeen new characteristics are described and documented, and five previously described traits are revised. In our reconstruction, the cephalon bore a pair of stalked eyes with setae along the convex margin and annuli at the basal part of the eye lobes, a median triangular sclerite, one pair of biramous antennules, and three pairs of uniramous appendages that may represent the mandibules, maxillules and maxillae, respectively. According to microtomography and fossil imaging, the thorax houses nine pairs of appendages, each identified as a quadripartite, comprising a protopodite, a reduced endopodite, flap-like setose exopodite, and annulated epipodite with numerous lamellae. This appendicular morphology provides additional evidence for the presence of exites (epipodites) in Palaeozoic arthropods. Re-examination of the trunk limbs of Cambrian euarthropods indicates that exites may be a common feature that evolved deep in arthropod phylogeny.
Water-carbon exchange at the leaf scale of rice in response to elevated temperature
Authors: Wu Jingwei , Zhao Yanchao
Published: March 2024

Global warming with climate change may affect the process of water consumption and carbon uptake of rice. However, the specific impact of elevated air temperature on the water-carbon exchange at the leaf scale of rice remains unclear currently. In this study, a three-year warming experiment was conducted in Jianghan Plain, China, and three treatments were set within natural supplemental light climate chambers in the field, mimicking ambient air temperature (ET0), an increase of 2°C (ET2), and an increase of 5°C (ET5), respectively. The objective was to investigate the direct effects of increasing air temperature on transpiration, photosynthesis, stomatal behavior, and leaf growth status of rice plants throughout the whole growth stage, while clarifying the indirect effects of variations in leaf growth status on carbon uptake and water consumption of rice. In this experimental area, the results indicated that treatments ET2 and ET5 during the vegetative growth phase led to an increase in transpiration rate (Tr) but a decrease in the net photosynthetic rate (An) compared to ET0, consequently lowering water use efficiency (WUE). Stomatal conductance (Gs) decreased initially and then increased with air temperature, showing a critical point at 35°C, while leaf area index (LAI) and leaf weight (LW) decreased due to increasing air temperature. However, during the reproductive growth phase, chlorophyll content (CCI), LAI and LW in treatments ET2 and ET5 were higher compared to ET0 due to a deceleration in the decline rate, enhancing leaf photosynthetic capacity and resulting in increased An. Consequently, the WUE also increased. The results showed that both elevated temperature and the leaf growth status differences caused by long-term high temperature had significant effects on leaf water-carbon exchange processes of rice.Key words: elevated temperature, transpiration, photosynthesis, stomatal conductance, water use efficiency
Variability in Anelastic Attenuation: Examining Temporal and Spatial Influences on Ground Motion Characteristics in Central Italy
Authors: Gabrielli Simona , Akinci Aybige , Gutierrez Carolina , Ojeda Vargas Javier , Arriola Sebastian , Ruiz Sergio
Published: March 2024

In recent decades, Central Italy has faced several seismic sequences, such as the one of the 2016-2017, started with the Amatrice mainshock (Mw6.2) in August 2016, followed by the Visso (Mw5.9) and Norcia (Mw6.5) earthquakes in October 2016 (hereafter AVN). Given the region's frequent seismic activity and heigh seismic risk, the use of ground-motion simulations becomes crucial for seismic risk assessment and earthquake engineering applications. Ground motion characteristics have been already investigated in the area for the Mw6.2 Amatrice and Mw6.5 Norcia earthquakes, using stochastic and numerical approaches.Moreover, to predict ground motion from hypothesized events, it is fundamental to define the attenuation characteristics of the area and the relationship with the ground motion models.In this study, we investigate the variability of seismic wave attenuation in strong-ground motion simulation in the Central Apennines, employing stochastic simulations. Initially, we compute the quality factor Q values for the region, deriving the total attenuation Q as a function of frequency for the 2016-2017 seismic sequence. To visualize the variation of the attenuation, a 2D kernel-based imaging of coda-Q space is applied, confirming an increment in attenuation during the AVN sequence in the fault plane zones.Then, we incorporate the acquired frequency-dependent Q values as input parameters into the simulations of ground motion. This methodology replicates stochastically strong-ground motion at high frequencies, reproducing horizontal and vertical accelerograms and using as input information from the source (stress drop, rupture time, slip distribution and radiation pattern). The estimations are then correlated and validated against observed peak ground accelerations and spectral accelerations for the Amatrice and Norcia fault planes, followed by a comparison with the ground motion prediction equations used for the region.
Supporting Children’s Space Careers Education: “I’m a Space Person” 
Authors: Archer Martin , Waters Cara , Foster Simon , Portas Antonio , Davenport Carol
Published: March 2024

Educational research shows participation issues across Science Technology Engineering and Mathematics (STEM) are largely due to whether students see these areas and their potential career opportunities as relevant and accessible to “people like me”. These perceptions form early and remain relatively stable with age, which has led to recommendations for increased provision and quality of careers education/engagement at both primary and secondary levels. Of STEM-related fields, the space sector is one of the most diverse and rapidly growing industries worldwide and of strategic priority to many countries. This highlights the need for space careers education in particular. We introduce a new space careers resource “I’m a Space Person”, which leverages personal attributes to help children identify with different space careers. Information about each of the 36 varied roles featured is distilled down onto a simple postcard format, with an accompanying website to enable further exploration. Resources for parents/carers and teachers are also provided to assist them in supporting children’s careers education. We present the development process of this resource and its usage thus far by the UK Space Agency in a nationwide roadshow. Finally, we discuss how the existing resources could be used and adapted for different countries and contexts.
A combined approach for the correlation between indoor radon and geological background: application in the western Ligurian Alps (Italy)
Authors: Bonorino Linda , Beccaris Gianluca , Bisi Paola , Chiozzi Paolo , Cogorno Andrea , Filippi Elga , Narizzano Riccardo , Prandi Sonja , Verdoya Massimo
Published: March 2024

Radon (222Rn) is one of the most common naturally occurring radioactive elements and is particularly interesting to environmental issues, for it is considered a carcinogenic gas. It is a decay product of 238U, contained in most rocks and soils, and can easily escape from the ground to accumulate in closed spaces where it may become dangerous. The knowledge of its potential is vital to urban development plans and to protect people from potential hazards. We recently conducted monitoring campaigns in Liguria (NW Italy) to investigate the relations between the observed indoor radon concentrations and the geo-lithological background. We focused on the geological units of the Western Alps, characterized by various lithotypes, ranging from sedimentary to metasedimentary and metavolcanic rocks. The natural gamma radiation was measured on outcrops. Spectrometric measurements indicated that metamorphic acid rocks have the highest specific activity values of 238U (75-85 Bq/kg). In metasedimentary rocks, quartz and mica schists show the highest concentration of 238U, with an average specific activity of 56 Bq/kg. Sedimentary rock types are characterized by average specific activities < 40 Bq/kg., The dosimetric indoor surveys highlighted that about 40% of the investigated public and private buildings show indoor radon values above 200 Bq/m3. These preliminary campaigns revealed a relationship between the uranium content of the bedrock and the indoor radon. The correlation can be used to predict the geogenic radon potential based on a geological background when dosimetric data are few or scattered. In this paper, we refined our early analysis by integrating the dataset with further spectrometric and indoor dosimetric records, which were also coupled with soil radon measurements. The radon concentration in soil was investigated focusing on the sites where the previous monitoring campaigns showed high indoor radon concentrations. Soil radon was recorded at depths between 50 and 80 cm, where radon diffusion from the ground to the buildings very likely occurs. Soil radon concentrations substantially agree with spectrometric measurements. The largest concentration of 222Rn was found in the soils on more acid metamorphic rocks (porphyroid and porphyric shists) with values of about 100 kBq/m3. The lowest values about (20 kBq/m3) were recorded in soils occurring in sedimentary rocks. Despite the limitations and uncertainties, mainly related to the uneven data coverage and the complex interaction between the building and the bedrock, the combined techniques can identify areas of potentially high indoor radon concentrations.
Gravity inversion using L0 norm for sparse constraints
Authors: Zhu Dan
Published: March 2024

Gravity surveys constitute an important method for investigating the Earth’s interior based on density contrasts related to Earth material differentials. Because lithology depends on the environment and the period of formation, there are generally clear boundaries between rocks with different lithologies. Inversions with convex functions for approximating the L0 norm are used to detect boundaries in reconstructed models. Optimizations can easily be found because of the convex transformations; however, the volume of the reconstructed model depends on the weighting parameter and the density constraint rather than the model sparsity. To determine and adapt the modelling size, a novel non-convex framework for gravity inversion is proposed. The proposed optimization aims to directly reduce the L0 norm of the density matrix. An improved iterative hard thresholding algorithm is developed to linearly reduce the L0 penalty during the inner iteration. Accordingly, it is possible to determine the modelling scale during the iteration and achieve an expected scale for the reconstructed model. Both simple and complex model experiments demonstrate that the proposed method efficiently reconstructs models. In addition, granites formed during the Yanshanian and Indosinian periods in the Nanling region, China, are reconstructed according to the modelling size evaluated in agreement with the magnetotelluric profile and density statistics of rock samples. The known ores occur at the contact zones between the sedimentary rocks and the reconstructed Yanshanian granites. The ore-forming bodies, periods, and processes are identified, providing guidance for further deep resource exploration in the study area.
The Excitation of Eastward Second Harmonic Poloidal Waves Through Drift-Bounce Resonance with Protons in the Magnetic Dip
Authors: Zhuang Yan , Yue Chao , Li Li , Zhou Xu-Zhi , Zong Qiu-Gang , Li Xing-Yu , Yin Ze-Fan , Liu Ying , Fu Haobo , Liu Zhi-Yang , Wang Yong-Fu
Published: March 2024

The drift-bounce resonance between ultralow-frequency (ULF) wave and charged particles is an efficient way to transfer energy. In this study, we report the excitation of ULF waves through drift-bounce resonance with protons in the magnetic dip for the first time. On 4 September 2015, Van Allen probe B observed ULF signals with a frequency of ~10 mHz inside the magnetic dip during substorms at the dusk side. The ULF waves are further diagnosed as second harmonic poloidal waves. The 54-67 keV protons in the magnetic dip exhibit oscillations with the same period as ULF waves, providing evidence for drift-bounce resonance. Through finite Larmor radius effects combined with simulations, we determined the ULF waves propagate eastward with an azimuthal wave number of ∼240. The sign of df/dW reveals that the ULF waves are excited and related to the outward radial gradient of proton phase space density. 
Transient modeling for the ocean redox condition during the mid-Cretaceous oceanic anoxic event 2
Authors: Cui Qi , Zhang Jian , Hu Yongyun
Published: March 2024

Oceanic Anoxic Event 2 (OAE2) is one of the largest disruptions for the global carbon cycle in the mid-Cretaceous, which was linked to global warming and nutrient release from continental weathering. However, their respective contributions to the seafloor anoxia remain unclear. Here we perform transient numerical simulations using an intermediate-complexity Earth system model to study their influences on the mid-Cretaceous OAE2. The modeling results show that global warming due to carbon dioxide degassing could influence the seafloor oxygen contents distinctly through the ocean circulation change, but has a minor influence on the seafloor anoxia during the OAE2. The phosphate due to continental weathering associated with global warming added to the ocean further decreases the seafloor oxygen content, especially leading to the North Atlantic seafloor anoxic area expansion and the anoxia of the Southeastern Pacific Basin. When different continental weathering rates are taken into account, the modeled anoxic area from simulations with an increase of approximately 1.3 to 1.7 times the pre-OAE2 level is comparable with the estimate based on proxies, which tentatively constrains the continental weathering rate during the OAE2. This simulation would enhance our understanding of the intricate biological and geochemical processes in the oceans as the increasing atmospheric carbon dioxide concentrations.
Salinity influence on plant traits and photosynthesis in selected peatland macrophytes
Authors: Go Amabelle , Schubert Hendrik , Jurasinski Gerald
Published: March 2024

Coastal peatlands, despite their ecological importance are at risk from a range of disturbances that render this habitat vulnerable, affecting their productivity and could potentially trigger ecosystem shift. Salinity is one of the factors affecting the structural and functional aspects of macrophytes in peatland environments. This study aims to assess the impacts of different salinity levels on the growth, biomass, and photosynthetic performance of peatland plants using a mesocosm approach. Four treatments of varying salinity were implemented: Saline (C+) with salinity of 20 ppt, Freshwater (C-) with salinity of 0 ppt, 22 and 55 pulses where the plants were exposed alternately to water with salinities of 20 ppt and 0 ppt every 2 and 5 days, respectively.  Two macrophyte species, Phragmites australis and Typha latifolia, were planted in mesocosm tanks. Over a 16-week period, various parameters including leaf length, leaf area, plant height, growth, biomass, and photosynthetic responses were monitored to evaluate the extent of salinity-induced stress. Results indicate that P. australis exhibited no significant difference in growth rates and biomass across treatments. Growth monitoring showed peak observed at the 8th week post-transplanting. Leaf area and leaf production also showed no significant variations. While shoot production increased initially, peaked at the 8th week, and declined thereafter. T. latifolia on the other hand, displayed growth rate variations favoring the freshwater (C-) and less frequent water change (55) treatments. The 55 pulses exhibited the highest absolute growth rate, but growth regressed after 8th week in treatments exposed to salinity changes. Leaf production in saline (C+) and higher frequency of water changes (22) showed a steep decline from 10th week onward. Saline treatment resulted in the lowest leaf production, leaf area, and biomass. This study contributes insights on the varying responses of macrophytes to salinity stress, demonstrating acclimation kinetics, and identifying salinity limits. 
Reconstructing the spatial patterns of dust plumes in geostationary satellite images over North Africa using in-painting techniques
Authors: Kanngießer Franz , Fiedler Stephanie
Published: March 2024

North Africa is the world’s largest source region of mineral dust. Mineral dust aerosol itself plays an important role in the climate system, as it is, for example, directly and indirectly influencing radiative transfer and providing nutrients for marine and terrestrial ecosystems. In addition, airborne mineral dust has adverse effects on air quality and public health.Satellite observations can provide large spatial coverage of dust plumes, which facilitates the study of dust sources, transport pathways, and sinks. Such large spatial coverage can be combined with a high temporal resolution by instruments onboard geostationary satellite. An example of such an instrument is the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) onboard the geostationary Meteosat Second Generation satellites (MSG). The full spatial extent of dust plumes in SEVIRI observations is frequently obscured by clouds. To overcome this limitation, we propose the use of machine-learning-based image in-painting techniques.Machine-learning-based image in-painting techniques can restore damaged images of structures like buildings, cars, landscapes, insects or human faces by learning the typical patterns of these structures. Image in-painting algorithms have in recent years been successfully adapted to reconstruct missing geophysical data. In this study, we use an off-the-shelf implementation of an image in-painting algorithm and developed a method for applying it to satellite-observed dust plumes. The algorithm is trained on reanalysis fields of the dust aerosol optical thickness combined with temporally corresponding cloud masks obtained from MSG-SEVIRI. In a next step we use this trained algorithm to restore the full spatial extent of dust plumes on grey-scaled images of North African dust plumes during 2021 and 2022, derived from the SEVIRI Dust RGB product. We test the reconstructed dust plumes against independent data, derived from dust forecasts provided by the WMO Barcelona Dust Regional Center. Our reconstructions spatially and temporally agree well with output from the forecast model ensemble. The proposed method is adaptable to other satellite products in the future, including products from the Meteosat Third Generation Flexible Combined Imager (MTG-FCI).ReferenceKanngießer and Fiedler, 2024, “Seeing” beneath the clouds - machine-learning-based reconstruction of North African dust plumes, AGU Advances, In Press.
Consistently combined Earth Rotation Parameters at BKG - Adding SLR data to VLBI and GNSS
Authors: Klemm Lisa , Thaller Daniela , König Daniel , Flohrer Claudia , Walenta Anastasiia
Published: March 2024

We present BKG´s current activities in the field of combined data processing of different space-geodetic techniques. The primary goal of the combined analyses is the improvement of the consistency between the techniques through common parameters, mainly Earth Rotation Parameters (ERP), and thereby to improve also the resulting ERPs. In previous studies, we have investigated different combination approaches using VLBI and GNSS data and generated ERP series with latencies of about 1-2 or 14 days, depending on the input data used. In this way, we achieved a significant improvement in accuracy, especially for the dUT1 series, compared to the individual technique-specific solutions. The processing is based on datum-free normal equations (provided via SINEX files), which allow a rigorous combination on the normal equation level instead of the observation level.Our current activities in the area of multi-technique combination are focused on augmenting the combination of GNSS and VLBI data with SLR data. It is expected that the SLR technique has the potential to improve the combined ERP solution, especially the highly variable dUT1 parameter, by providing a stable LOD contribution. Due to its short latency of about 1 day, the SLR-DAILY product is basically well suited to expand the database of our Rapid EOP series, which is currently only based on GNSS Rapid and VLBI Intensives data. However, the official SLR-DAILY product of the ILRS is a 7-day solution that explicitly contains polar motion (only as constant offsets over 24 hours) and LOD, but no dUT1 parameters and no polar motion rates. Therefore, this solution is not optimal for our combination approach because the parameterization of the ERPs is not identical to the other techniques that uses offsets and rates for all ERPs. However, the in-house ILRS Analysis Center allows us to generate a customized SLR solution that has an improved parameterization of the ERPs and, thus, is optimized for the multi-technique combination. We investigated the SLR data with respect to the quality of the resulting ERP series and integrated the data into our combination process. We present the impact of SLR on the combined ERP product and the challenges of extending the combination with this data.