bluuebunny/crossref_metadata_2025 huggingface dataset:
A hybrid analytical and machine learning framework for groundwater resources management
Authors: Iraola Aitor , Pool María , Nardi Albert , Vilanova Ester , Molinero Jorge , Dentz Marco
Published: March 2024

In Hydrogeology, numerical models are presented as essential tools for integrating, understanding, and predicting groundwater processes. However, these models face significant challenges: on the one hand, boundary conditions and hydraulic parameters are often subject to a large degree of uncertainty, and, on the other hand, numerical models usually require advanced solving and calibration techniques that generally imply long runtimes. Recently, innovative machine learning models have emerged as a promising alternative to address these issues and thus, the application of artificial intelligence in hydrology has increased significantly. In this study we present a hybrid model designed to predict groundwater heads in response to pumping. This model generates an initial analytical approximation of groundwater heads which is later enhanced by a machine learning framework based on recurrent neural networks. A real application of a pumping field for urban supply in Spain is presented as an illustration of the practical application of the presented methodology. Following model training and validation, we have also integrated a genetic algorithm to optimise flow rates, aiming to minimise energy consumption and/or head drawdowns. The results reveal that our hybrid approach achieves highly accurate head predictions with normalised absolute mean error lower than 4% which implies that the model reproduces properly the head measurements. Additionally, the optimisation algorithm successfully reduces energy consumption by 25%. This methodology represents a groundbreaking approach to quantify the effects of intense pumping and to facilitate long-term management of groundwater resources.
Forecasting solar wind speed from coronal holes and active regions
Authors: Collin Daniel , Shprits Yuri , Bianco Stefano , Inceoglu Fadil , Hofmeister Stefan , Gallego Guillermo
Published: March 2024

Coronal holes (CHs) have long been known as one of the main sources of high-speed solar wind streams, but recent evidence suggests that active regions (ARs) also play a significant role as solar wind sources. In this study, we aim to investigate the impact of both CHs and ARs as source regions of the solar wind. Both structures can be identified in extreme ultra-violet (EUV) solar images several days before they become geoeffective. We exploit this relation to construct a model that forecasts the solar wind speed at L1. First, we accurately detect and track the evolution of CHs and ARs over time by employing a segmentation algorithm on solar images. Next, we extract features from the indicated regions in EUV images and magnetograms, such as area and location of the source regions and the corresponding magnetic field configurations. These features, along with solar wind data from previous solar rotations and the current state of the solar cycle, are assimilated over time in a data-driven model that predicts the hourly solar wind speed at L1 four days in advance. During model training, we particularly focus on preserving the distribution of observed solar wind speeds to overcome a common drawback of data-driven solar wind speed prediction models, namely the underprediction of the peak values of solar storms. By adding a suitable regularization to the loss function, we force our model to follow the physical behavior more closely, which results in a significantly improved accuracy for predicting solar storms. Finally, we use our model to draw conclusions about the physical relevance of CHs and ARs for solar wind speed models. The model's performance is evaluated through cross-validation on 14 years of data and compared to other state-of-the-art models.
Partitioning of multiple elements as a function of seawater [Ca2+]: results from foraminiferal culture experiments. 
Authors: Pacho Laura , de Nooijer Lennart , Reichart Gert-Jan
Published: March 2024

Climate reconstructions are important for validating climate models and hence constrain climate change predictions. Such reconstructions are based on indirect tools (proxies) in which a fossil or chemical remnant corresponds to an environmental parameter. When employing foraminifera as proxies, elemental concentrations in their shells have been shown to correlate with environmental parameters including temperature (that determines the calcite’s Mg/Ca), seawater [HCO3-] (Sr/Ca and B/Ca) and [CO32-] (S/Ca). When reconstructing theses parameters on longer geological timescales (i.e. millions of years), the seawater’s major ion concentrations may affect these proxy relationships. Especially the concentration of calcium will affect all of these calcitic elemental ratios and therefore, we varied [Ca2+] in controlled growth experiments to test its effect on incorporation of Mg, Sr, B and S in the benthic foraminifer Amphistegina lessonii. For the divalent cations we find a decrease in the partition coefficient (D) for Mg (DMg) with a changing [Ca2+] (and hence seawater Mg/Ca) while DSr does not vary significantly with [Ca2+]. For SO42- and B(OH)4- against S/Casw and B/Casw respectively, we observe a significant decrease in the partition coefficients with decreasing [Ca2+]. These results gives new information for SO42- and B(OH)4- incorporation and represents a step forward towards comprehending the impact of [Ca2+]sw alterations on foraminiferal calcite chemistry and hence their application as paleoproxies in deep time. 
Environmental parameters affect palaeothermometry of Alkenones and GDGTs: A case study at the Southern Chilean Margin (46° S)
Authors: Hagemann Julia Rieke , Martínez-Garcia Alfredo , Lamy Frank , Kaiser Jérôme , Lembke-Jene Lester , Arz Helge W. , Lange Carina B. , Tiedemann Ralf
Published: March 2024

Isoprenoid glycerol dialkyl glycerol tetraethers (isoGDGT) and alkenones are widely used tools for reconstructing past sea surface and subsurface temperatures. IsoGDGTs are membrane lipids synthesized by ammonia-oxidizing Nitrososphaerota and contain up to four cyclopentane moieties. Alkenones are unsaturated carbon chains, whose origin is mainly the coccolithophorid algae Emiliania huxleyi. The number of moieties of the isoGDGTs, as well as the degree of unsaturation of the alkenones depends on the ambient water temperature. Both biomarker-synthesizing organisms (Nitrososphaerota and E. huxleyi) are subject to several environmental influences, like nutrient availability, light conditions, salinity changes, changes in the biomarker-producing community, or terrigenous input, that can bias the temperature signal. In this study, we focus on the influence of terrigenous input and changes in salinity on both biomarkers. We use the 17 m-long piston core MR16-069 PC03, which is located at 46° S and ~150 km offshore the Chilean margin. This core covers a full glacial-interglacial cycle (140 ka) and shows recurring high inputs of terrigenous material and freshwater during the glacial period. This extreme contrast between interglacial and glacial is suitable for examining the influence of high terrigenous input on the temperature signal. Due to changes in the depositional setting, our results show a significant change in the expected temperature signal in both proxies during phases of high terrigenous input. We further discuss which temperature calibration is most appropriate for both biomarkers and conclude that for GDGT-based temperatures at this site, a calibration based on the TEXL86 index is more suitable, while for alkenone-based temperatures the UK37 index appears to be most accuracy.
Navigating Uncertainty in Flood Risk Perception in the Context of Climate-Induced Extremes 
Authors: Höllermann Britta
Published: March 2024

The flood events in Germany during the summer of 2021 have once again brought to the forefront the challenges in translating scientific knowledge into effective disaster risk management practices. This paper examines the critical gap between the scientific understanding of flood risks and the practical needs of those who manage these risks. We delve into the limitations of current scientific approaches, such as flood risk and hazard mapping, in fully addressing the complexities and nuances required for practical disaster risk management, especially in the face of uncertain climate change impacts. We examine the dynamics of how flood risk information, inclusive of uncertainties, is perceived and acted upon, highlighting the psychological factors influencing these processes. The paper discusses the challenges and opportunities in translating scientific risk assessments and forecasts into practical, actionable strategies for communities and stakeholders. By highlighting the disconnects and potential areas for improvement in the science-practice interface, this paper seeks to foster a more coherent and comprehensive approach to disaster risk management. Within the framework of the Safe Development Paradox, the importance of communicating uncertainties and evaluating their potential impacts on planning and emergency responses is discussed. This paper addresses uncertainties at multiple levels and for different stakeholders, highlighting the integration of uncertainty information as a vital step in preparing for surprises and ambiguities in the context of extreme meteorological and hydrological events induced by severe weather and climate change.
Analysis of atmospheric radon for uncertainty evaluation in regional-scale greenhouse gas emissions estimation 
Authors: Kikaj Dafina , Saba Mareya , Manning Alistair , Andrews Peter , Chung Edward , Foster Grant , Wenger Angelina , O’Doherty Simon , Rigby Matt , Rennick Chris , Pitt Joseph , Arnold Tim
Published: March 2024

Atmospheric transport model (ATM) uncertainty continues to be a significant constraining factor in making confident top-down (inverse model based) GHG emission estimates. Despite its importance, accurately gauging model uncertainty and capturing its temporal fluctuations remains a challenge. Inversion frameworks typically involve an empirical selection of data to be assimilated whereby only the data from periods where the ATM has the lowest uncertainties are used for the inversion.  There are numerous data filtering methods, that often depend on modelled parameters (mixing height, wind speed, potential temperature), which could result in data selection bias.To address this, we present analysis of radon measurements, a natural radioactive noble gas with simple and well-constrained source and sink. Radon’s unique characteristics make it an ideal tracer to study the transport and mixing of air and thus has potential to act as an independent metric to evaluate ATM performance. A new approach involves utilising measured and modelled radon (calculated using the Met Office Numerical Atmospheric Modelling Environment (NAME) dispersion model and radon flux map) to classify the ATM output uncertainty as either high (poor performance) or low (the best performance). This approach could be universally applied to any location measuring radon from a single inlet height and in conjunction with any other dispersion modelling scenarios.  To evaluate the effectiveness of the radon selection method, we assess the methane (CH4) emissions across the UK using four tall tower sites (part of the Deriving Emissions linked to Climate Change - DECC network): Heathfield, Ridge Hill, Tacolneston and Weybourne. The CH4 emissions are estimated by the Met Office’s inversion modelling system – Inversion Technique for Emission Modelling (InTEM). We will compare how emissions sensitivity varies between our radon-based approach and the current selection method, which relies on model parameters and the vertical gradient of CH4 measurements. This comparative analysis aims to demonstrate the potential advantages of using radon as a tool for improving the accuracy of ATM performance assessments in GHG emission estimates.
On the occurrence of volcanic lightning during vulcanian eruptions at Sakurajima volcano, Japan
Authors: Geisler Andre , Hort Matthias , Behnke Sonja , Edens Harald , Yamada Taishi , Iguchi Masato , Nakamichi Haruhisa
Published: March 2024

Volcanic eruptions are enigmatic, not in the least because of volcanic lightning during eruptions, which is still not fully understood. In an effort to better constrain conditions under which electrical discharges occur, we use data from a multicomponent geophysical network installed in 2019 at Sakurajima volcano, Japan. The network includes one vertically scanning Doppler radar to resolve the internal structure of the eruption column at a low temporal resolution, and two fixed Doppler radar systems to resolve the dynamics of the eruption near the vent at high temporal resolution. Eruption onset times were determined using a total of 5 infrasound stations. Electrical discharges were detected by three electric field mills (EFM), a thunderstorm detector from Biral (BTD), a lightning mapping array sensor (LMA) as well as a fast antenna (FA). In addition, meteorological conditions are monitored by a local weather station and eruptions were recorded by two different cameras. Sakurajima volcano is known to exhibit frequent complex eruptions/explosions often exhibiting a sequence of single pulses at intervals down to a few minutes. From our network, we generated an eruption catalog spanning 7 months of activity between June and Dec 2019. Out of this catalog, we select representative examples of multiple pulse events of different strength in terms of erupted mass, plume height, and eruption velocities. For each pulse within such a sequence, we analyzed the electrical activity as well as extracted eruption velocities, eruption volumes, plume heights, and eruption onsets among others. We find that the timing of the electrical discharges is correlated with the onsets of single pulses within a sequence. Furthermore, we can detect changes in the electrical activity ranging from times of CRF signals from small streamer discharges up to volcanic lightning while being able to track the erupted mass and plume extend at the same time. While electrical activity can increase together with eruptive strength, we also observe quite “strong” eruptions with little detectable discharges. On the other hand, less energetic eruptions are observed to produce electrical discharges, especially when the plume of a pulse rises through pre-existing ash clouds in the crater region.
Impact of recent forest protection on deadwood carbon stocks
Authors: Merganicova Katarina , Nowinska Renata , Merganic Jan , Kaczmarek Lech
Published: March 2024

The reduction of carbon dioxide levels in the atmosphere is one of the most pressing issues in the context of global warming. Forest ecosystems play a crucial role in carbon cycling due to their ability to store significant amounts of carbon in plant biomass, deadwood and soil. Research on deadwood has usually focused on the analysis of the current state without considering the history of forest stands. However, a recent trend in many European countries is to increase the area and number of protected areas, often encompassing previously managed forests. Such changes in forest management affect the abundance and character of deadwood, and thus and need to be considered in the analysis of its carbon storage capacity.The forests of Wielkopolski National Park in Poland are an excellent subject for such research. Until the end of the 18th century, they were owned by various landowners, leading to a highly diversified forest management driven by immediate needs of owners. In 1931, the first reserve, where logging was discontinued, was established. The current strict protection areas were mostly designated in 1957 when the park was legally established. Currently, strict protection mainly applies to habitats of oak-hornbeam forests Galio sylvatici-Carpinetum betuli, with other communities represented to a lesser extent.The assessment of deadwood carbon stock (DWCstock) was performed using the data from the field survey conducted between 2017 and 2018. Deadwood was inventoried at 98 circular plots (0.04 ha) located inside 12 strictly protected areas. We distinguished five deadwood categories: standing snags, logs, stumps, branches, and twigs, and 5 decay classes. All dead trees and their parts with a minimum top diameter of 3 cm were measured. The small diameter threshold was selected due to the abundant presence of shrubs that ocurrred during the 'renaturalization' of forest ecosystems. From the measured dimensions we derived DWCstock using species- and decay-specific volume equations, wood density and carbon fraction values. The data were stored in a relational database and further processed and statistically analysed in the R environment. The analysis showed a high variability of DWCstock between plots (from 0.19 to 92.43tC/ha, mean 15.03tC/ha). Almost 50% of the total DWCstock was assigned the third decay stage, while 10 and 5% of DWCstock occurred in the first and last decay stage, respectively. This indicates a substantial accumulation of the deadwood after the abandonement of forest management. In 60% of cases, the dominant species of deadwood did not coincide with the dominant species of the currently living trees suggesting the changes in species composition of forest ecosystems over time. The results show deadwood can be considered as a long-term memory of forest dynamics. The work highlights the need to use multiple data sources for a better understanding of ecosystem development.
Tackling practical challenges in anomaly detection for real-time monitoring of urban waste water networks
Authors: Schmidt Lennart , Weiske Felix , Schütze Manfred , Grimm Phillip , Polz Julius , Bumberger Jan
Published: March 2024

Waste water networks constitute a crucial element of urban infrastructure that are influenced by an observed increase in urban flooding events. To ensure regular network operation and minimal environmental impact, anomaly detection of urban waste water networks timeseries can serve as a real-time monitoring tool to detect a) sensor defects and b) system anomalies such as leaks or blockages. However, setting up such a monitoring system in practice can face significant challenges. These include limited amounts of labeled anomalies, heterogenous data quality, inconsistent measurement frequencies as well as instationarity of the system (sensor displacement and drop-out, changes in network layout). For the waste water network of a medium-sized German city, we set up machine learning based anomaly detection and present strategies to tackle aforementioned challenges. Our results show that autoencoder-based model architectures are valuable tools in such a context where only a minimal fraction (
Benefits of Ontologies in Earth System Science
Authors: Lammert Andrea , Martens Claudia , Loehden Aenne
Published: March 2024

The exponential growth of data due to technological developments along with an increased recognition of research data as relevant research output during the last decades substantiates fundamental challenges in terms of interoperability, reproducibility and reuse of scientific information. Being cross-disciplinary at its core, research in Earth System Science comprises divergent domains such as Paleontology, Marine Science, Atmospheric Sciences and Molecular Biology in addition to different types of data such as observation and simulation data. Within the various disciplines, distinct methods and terms for indexing, cataloguing, describing and finding scientific data have been developed, resulting in several controlled Vocabularies, Taxonomies and Thesauri. However, given the semantic heterogeneity across scientific domains, effective utilisation and (re)use of data is impeded while the importance of enhanced and improved interoperability across research areas will increase even further, considering the global impact of Climate Change to literally all aspects of everyday life. There is thus a clear need to harmonise practices around the development and usage of semantics in representing and describing information and knowledge.Using Ontologies (as a formal mechanism for defining terms and their relations) can help to address this issue, especially with regard to discovery, comprehension and metadata enrichment. If used and maintained, Ontologies also encourage metadata standardisation, idealiter across Disciplines. Examples for enhanced search options include (but are not limited to): term relations for variables as well as for topics and locations; Synonyms and Homonyms; autocomplete function for search terms; support of multiple languages. Indexing of research data can be improved using Ontologies e.g. by proposing terms for variable names or measurement units. Depending on their richness, ontologies ease e.g. finding, comprehension, processing, and reuse, both for human users as well as for automatic reasoning and processing.Ontologies can represent different levels of granularity, connecting domain specific Vocabularies as e.g. Climate Forecast conventions with generic Taxonomies for e.g. Scientific Disciplines or Funding Policies, thus extending the reach of scientific data to other user groups such as Journalists, Politicians or Citizens.For a beneficial usage of semantic artefacts, sustainability is the key: any kind of terminology service must be maintained to guarantee that terms and relations are offered in a persistent way. But if they are, Vocabularies, Taxonomies, Thesauri and Ontologies can serve as a driving force for improved visibility and findability of research output within and across different research areas. Why Ontologies matter, what they are, and how they can be used will be depicted on our Poster in an easy-to-understand way.
The influence of gas hydrate cyclicity on global and regional gas hydrate inventories
Authors: Burwicz-Galerne Ewa , Gupta Shubhangi
Published: March 2024

Gas hydrate (GH) formation and dissociation in natural systems is a complex, multi-process phenomenon controlled by local pressure-temperature-salinity (p-T-s) conditions and availability of methane gas. Our recent findings based on detailed analyses of GH systems using high fidelity multi-physics numerical model suggest that the long-term stability of the natural gas hydrate systems is not straightforward. On time scales ranging from hundreds to hundred of thousands of years, natural gas hydrate systems are able to develop, so-called, periodic steady-states characterized by a cyclic growth and dissolution of gas hydrate layers as well as a free gas migration through the gas hydrate stability zone (GHSZ). In this presentation, we show how these new results directly affect the estimates of global GH inventories and how they can be used to investigate the development of multiple bottom simulating reflectors (BSRs), slope failures, pockmarks, and gas migration pathways observed in the geological records that may have occurred spontaneously due to the internal system dynamics (i.e. gas hydrate cyclicity).On a global scale, we have quantified the potential effect of the periodic states expressed as a new uncertainty measure that sets the hard limits on the predictability of present-day gas hydrate inventories through steady-state analysis. On a regional scale, focused on high-latitude locations, we present a combination of system parameters leading to periodic states and provide uncertainty quantifications on the gas hydrate system stability and faith. In that context, we discuss the relation between the time-periods of the cyclic states and the external triggers affecting gas hydrate systems in the Arctic (e.g. anthropogenic warming, sea level changes, glacial- interglacial cycles, etc.).Keywords: methane cycle, global carbon budget, natural gas hydrate systems, periodic steady-states
Building transdisciplinary solutions at the first ever Climate Security Festival
Authors: Rantanen Rosa
Published: March 2024

Building transdisciplinary solutions at the first ever Climate Security FestivalIn September 2023, the first ever Climate Security Festival was organized in Helsinki, Finland. The event gathered close to 100 participants including researchers, civil society actors, climate security experts, artists, activists, students and others at the Finnish Meteorological Institute for two days.The idea of the festival was to bring people together and to enable discussing the risks related to climate change in an open and equal space. The two-day program was built around parallel workshop sessions, with the aim of strengthening and fostering cooperation between different sectors. The workshop topics were: 1) War and its effects on climate and the environment 2) Climate, death & (mental) wellbeing and 3) Who owns the climate security discussion? In addition, the festival included two keynote talks, joint discussion, a transdisciplinary poster session, artistic performances and side program; a safety walk, a photography exhibition and a collaboration movie screening and panel discussion in collaboration with Finland’s biggest film festival. The event was organized in person and participants were encouraged to leave aside their electronic devices, titles and prejudice.Based on the encouraging results and feedback from participants, some key findings from the festival can be pointed out and utilized in building sustainable collaborations and co-creating climate solutions in geosciences and beyond. The results indicate, for example, the importance of;embracing a truly transdisciplinary approach (including non-academic methods)
putting the work in building safer spaces for discussing ethical, fundamental and even painful topics in the context of climate change and geosciences
involving artists, art institutions and artistic methods in climate security related discussions and action in non-performative roles
expanding ownership of the discussion on climate change related risks beyond ‘traditional’ research and security/foreign political frameworks
Results are presented briefly with visual materials from the festival, workshop proceedings and participant feedback.The festival was organized by the Safer Climate network (Institute for Atmospheric and Earth System Research, University of Helsinki) in collaboration with the Committee of 100 in Finland. The next festival will be organized in 2024.
“Looking deep” into shallow ground: scientific drilling and continuous monitoring in recharge areas as a key to the understanding of groundwater quality dynamics and subsurface ecosystem functioning
Authors: Lehmann Robert , Aehnelt Michaela , Grelle Thomas , Lehne Carlos , Totsche Kai Uwe
Published: March 2024

Core-drilling and groundwater well operation in topographic recharge areas have been rarely applied for groundwater quality monitoring or ecosystem exploration, simply due to lacking of productive water bodies in up to >100 m thick aeration zones. The scarcity of observers and data, and neglection in modelling opposes our efforts to unravel the role of thick hillslope aeration zones for services like water provision, water purification and biogeochemical cycling (Lehmann & Totsche, 2020). To fundamentally understand how groundwater quality comes about as a function of inputs and how climate and land use change will affect this quality, we concentrate our investigations on the soil-aeration zone-phreatic zone continuum in topographic highs. From our Hainich Critical Zone Exploratory in central Germany, we present methods and workflows for low-impact scientific drilling and construction of monitoring wells optimized for representative sampling of the total mobile inventory (Lehmann et al. 2021), and results from the analysis of drill cores, borehole geophysical data and multi-year environmental monitoring data. We found that transient (fluid) flow patterns contribute to groundwater quality dynamics, whereby overall aeration zone-phreatic zone-interactions cause quality fluctuations even in deep and isolated habitats. Results from recent drilling campaigns (2023) comprise the detection of narrow oxic zones (fractures, flow paths) also within mudstone-dominated strata (anoxic aquifer-storeys) and weathering-induced hydrofacies differences that indicate further complexity of habitat structures and ecosystem functioning across recharge(-discharge) zones.  References:Lehmann, R., Totsche, K. U. (2020). Multi-directional flow dynamics shape groundwater quality in sloping bedrock strata. Journal of Hydrology 580, 124291. https://doi.org/10.1016/j.jhydrol.2019.124291 Lehmann, K., Lehmann, R., Totsche, K. U. (2021) Event-driven dynamics of the total mobile inventory in undisturbed soil account for significant fluxes of particulate organic carbon. Sci. Total Environ. 756, 143774. https://doi.org/10.1016/j.scitotenv.2020.143774
Non-Classical Crystallization in Moon-Milk Deposits in the Nerja Cave, Spain 
Authors: Bonilla-Correa Sarah , Ruiz-Agudo Encarnación , Asta Andrés María Pilar , Huber Lisa , Jiménez de Cisneros Concepción , Liñán-Baena Cristina
Published: March 2024

The Nerja Cave is located in an alpine folding chain, specifically in the Inner Zone of the Betic Range (SE, Spain), and it is developed within middle Triassic dolomite marbles (Carrasco et al., 1998). Its mean annual temperature is 18.1 ± 0.1 °C (Jiménez de Cisneros et al., 2021). Moon-milk deposits, a white substance present inside caves. Samples were collected in the touristic part of the cave and were characterized using synchrotron high-resolution XRD (HR-XRD), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). We detected the presence of amorphous magnesium carbonate (AMC), huntite, and dolomite. Additionally, the AMC formation and the subsequent crystallization process were studied in laboratory conditions to gain a more comprehensive understanding of the processes occurring in the cave. We performed titration experiments using magnesium and calcium chloride solutions and potassium carbonate buffers to investigate nucleation and transformation processes at elapsed times (1, 2, 7, and 14 days). The filtered solids were characterized by XRD, SEM, FTIR, Raman, and TEM. The results of these analyses highlighted the critical role of AMC in the formation of Ca-Mg crystalline carbonates.Acknowledgment to financial support is given by the Spanish Ministry of Science and Innovation through the research project PID2021-125305NB-I00 and the project from the Junta de Andalucía through the EMERGIA research program under the grant agreement EMERGIA20_38594.Carrasco F, Durán JJ, Andreo B, Liñán C, Vadillo I (1998) Consideraciones sobre el karst de Nerja. Karst en Andalucía 173–181Jiménez de Cisneros, C., Peña, A., Caballero, E., & Liñán, C. (2021). A multiparametric approach for evaluating the current carbonate precipitation and external soil of Nerja Cave (Málaga, Spain). International Journal of Environmental Research, 15, 231-243.
Mechanisms of atmospheric CO2 drawdown during Marine Isotope Stage 4 based on Atlantic deep-water temperature and bottom-water oxygenation reconstructions 
Authors: Radionovskaya Svetlana , Gottschalk Julia , Thornalley David , Greaves Mervyn , Skinner Luke
Published: March 2024

Understanding the evolution of deep ocean circulation and chemistry over the last glacial cycle is key to elucidating the ocean’s role in modulating atmospheric CO2 changes on millennial and orbital timescales. MIS 4 is a key paleoclimatic interval of the last glacial inception for assessing the role of the deep-ocean carbon storage in driving atmospheric CO2 levels, because it is characterized by a large decrease of air temperature and a rapid atmospheric CO2 drop of ~40 ppmv, and includes several millennial climatic events, for example Heinrich Stadial 6. Although various paleo proxy records suggest a weakened Atlantic overturning during MIS 4, and particularly HS 6, changes in AMOC strength and the geometric extent of NADW shoaling remain poorly understood. Here, we present deep-water temperature reconstructions based on infaunal benthic foraminiferal Mg/Ca ratios and bottom water oxygen concentration reconstructions using redox-sensitive foraminiferal U/Ca, from the deep North (~2.65km) and South (~3.8km) Atlantic to assess the changes in deep water hydrography and by extension circulation.Our reconstructed deep-water temperature changes from the Iberian Margin (~2.65 km water depth) suggest a stronger influence of colder southern sourced waters during MIS 4 and particularly during HS 6; and a clear subsurface warming during MIS 5a stadials. Meanwhile, changes in deep-water temperatures in the Atlantic Sector of the Southern Ocean (SO) closely follow variations in Antarctic temperature, atmospheric CO2 and the mean ocean temperature, likely mediated by buoyancy forcing in the SO, which is in turn likely linked to sea-ice expansion at the MIS 5a/4 transition. Together with (arguably smaller) contributions from reduced air-sea gas exchange efficiency in the SO, these combined changes would have lowered atmospheric CO2through more efficient carbon sequestration in an expanded deep Atlantic reservoir during MIS 4, through their impact on the solubility- and soft tissue “pumps” (i.e. the ocean’s disequilibrium and respired carbon budgets). Indeed, bottom water oxygenation reconstructions from the South Atlantic support the conclusion that the Southern Ocean appears to have represented a significant reservoir for sequestering CO2 away from the atmosphere during MIS 4.
Assessing the impacts of future climate scenarios on soil management practices and their hydraulic proprieties
Authors: Moura Lima Edberto , Böning Kristin , Ding Friederike , Stumpp Christine , Holzkämper Annelie , Mehdi-Schulz Bano
Published: March 2024

Soil management practices influence soil physical parameters and crop productivity. No-till farming, which is a key component of conservation agriculture, is considered a sustainable alternative to conventional agriculture. The extent to which soil conservation management practices can mitigate the impacts of extreme events (heavy precipitation events and drought) remains unknown, and is examined as part of the SoilX project. This study focuses on two different tillage management practices and their effects on soil hydraulic properties, soil structure, and crop yields under current and future climate conditions. An experimental study site that is a Long-Term Field Experiment (LTE) since 2006 located in Hollabrunn, Lower Austria, was used for soil sampling and crop modelling. The site is located in a Pannonian climate, with average annual (1991-2020) precipitation of 493 mm and a mean air temperature of 9.8 °C. The soil is classified as a silt loam calcareous Chernozem under the WRB or as Typic Vermudoll under the US Soil Taxonomy. The experimental layout comprised two soil tillage treatments (conventional tillage (CT) and no-tillage (NT), both with annual crops and winter cover crops) arranged in a randomized block design. The crop model APEX (Agricultural Policy/Environmental eXtender) model was set up for both treatments to assess the impacts of CT and NT on soil physical properties and their respective hydrological properties. Field soil samples were taken from both treatments (up to 50 cm depth) and analyzed for soil bulk density, soil organic matter (SOC), water stable aggregates (WSA), unsaturated infiltration rates (determined with TDI), water retention curves, and oxygen isotopes in soil pore water. These field measurements were used to parameterize the APEX model. Field operations between 2009 and 2023 also provided model inputs on crop cultivation cycles, tillage, fertilization, sowing, crop protection, and harvesting. The yield (dry matter Mg ha-1) per plot was used for model calibration. From the soil samples obtained in 2023 differences between CT and NT were determined with respect to bulk density and soil water content, i.e. at 10 cm, the unsaturated infiltration rates were higher in CT. The future climate simulations (2050-2100) derived from regional climate models (RCMs) with different representation pathways (RCPs) were input in APEX to assess the impacts of climate change on the soil physical and hydraulic properties (SOC, infiltration rates, soil water storage) under CT and NT. The research results quantify differences in soil physical and hydraulic properties in a future climate, particularly focusing on the extreme events. The findings provide information on soil management strategies to potentially mitigate the adverse impacts of heavy precipitation events and droughts in agricultural cropping systems.
Plate flexure and tectonic tilt along the Emperor Seamount Chain 
Authors: Xu Chong , Wessel Paul , Watts Anthony , Boston Brian , Dunn Robert , Shillington Donna
Published: March 2024

The Hawaii-Emperor seamount chain stretches westward from the “Big Island” of Hawaii for over 6000 km until the oldest part of the chain are subducted at the Kuril and Aleutian trenches. Still regarded as the iconic hotspot-generated seamount chain it has been sampled, mapped, and studied to give insights into numerous oceanic phenomena, including seamount and volcano formation and associated intraplate magma budgets, the past absolute motions of the Pacific plate, the drift of the Hawaiian plume, and the thermal and mechanical properties of oceanic lithosphere. Previous work (Wessel et al., EGU 2023 abstract) used a high-resolution free-air gravity anomaly and high-resolution bathymetry data set, together with fully 3-dimensional flexural models with variable volcano load and infill densities, to estimate the optimal effective elastic thickness, Te, and load and infill densities along the Emperor Seamount chain. Here, we use these parameters to calculate the tectonic tilt of a pre-existing volcano that occurs as each new volcano in a seamount chain is progressively added by flexure to the Pacific oceanic plate. We found tilts in the range 0.1-2.1 degrees which are modest compared to other cases of progressive flexure, for example, at seaward dipping reflector sequences in volcanic rifted margins (~5-15 degrees) but may be significant enough to modify the morphology of volcano summits and the stratigraphy of the sequences that accumulate in their flanking moats. They may also modify the physical properties of the edifice such as their magnetisation vectors.Wessel, P., A. B. Watts, B. Boston, C. Xu, R. Dunn, and D. J. Shillington “Variation in Elastic Thickness along the Emperor Seamount Chain”, EGU 2023 Abstract
Can CO2 degassing explain the climate and biogeochemical perturbations during Cretaceous OAE2?
Authors: Krewer Chiara , Mills Benjamin J. W. , Zhao Mingyu , Poulton Simon W.
Published: March 2024

The Late Cretaceous is characterized by extreme greenhouse conditions with high temperatures and high atmospheric pCO2 that have been proposed to be directly linked to the emplacement of large igneous provinces (Caribbean and Madagascar LIP). As a result of these extreme conditions, an increase in organic carbon burial has been recorded on a global scale during Oceanic Anoxic Event 2 (OAE2, ~94.5 Ma), which has been linked to amplified continental weathering1,2 and increased marine nutrient availability. However, despite the event being well studied, a model that directly estimates the combined biogeochemical effects of LIP-derived CO2 input – and compares this to the combined geological record –is lacking.Here we use a new biogeochemical ocean-atmosphere-sediment multi-box model3 which produces a self-consistent estimate of the global C, O, Fe, S and P cycles across the marginal and deep ocean, and we explore the outputs of this model for carbon isotope excursions (CIEs) in carbonates and organic carbon as well as for high and low latitude paleo-sea-surface temperatures (SSTs) under a LIP CO2 degassing scenario for OAE2.The model results indicate that in order to reproduce both the global SST records and CIEs, the annual rate of volcanic input of CO2 must be higher than the estimated range from previously published research. Furthermore, to reproduce the magnitude of the positive CIEs, the model requires an additional source of bioavailable iron beyond that which is liberated through global weathering enhancement under high CO2. We investigate the possibility that hydrothermal input of Fe to the deep ocean during LIP activity helped boost productivity during OAE2, and suggest that the balance between tectonic inputs of CO2 and limiting nutrients may help explain why some OAEs are accompanied by positive carbon isotope excursions and some by negative excursions.References:1 Pogge von Strandmann et al., 2013, Nature Geoscience2 Nana Yobo et al., 2021, GCA3 Zhao et al., 2023, Nature Geoscience
Development of multi-sensor algorithm for enhancing the spatial and temporal resolution of Surface Soil Moisture 
Authors: Sharma Ananya
Published: March 2024

Development of multi-sensor algorithm for enhancing the spatial and temporal resolution of Surface Soil MoistureAnanya Sharma1, Manika Gupta1, Vikrant Maurya1, Juby Thomas1, Prashant K Srivastava21) Department of Geology, University of Delhi, Delhi, India2) Institute of Environment and Sustainable Development, Banaras Hindu University, Banaras, IndiaAbstractSurface soil moisture (SSM) is a crucial antecedent parameter for determination of various hydro-geomorphological conditions in the field of atmospheric and agricultural science. The available remotely sensed SSM datasets (AMSR-2, SMAP, SMOS) present with significantly degraded accuracy when compared to the in-situ measurements in heterogenous regions of India, as soil moisture retrievals through earth observation satellites are considerably sensitive to varying vegetation cover, biomass and surface roughness. A notable trade-off exists between the enhancement of spatial and temporal resolution. Advancements in methodological innovations must continually be sought to mitigate this trade-off, pushing the boundaries of what is achievable in both spatial and temporal dimensions. In the present study, we have utilized two distinct methodologies for the derivation of SSM product at a spatial resolution of 20 meters. The first approach involves the utilization of an enhanced Land Surface Temperature Product (LST) at a spatial resolution of 20 meters, in conjunction with Landsat-8 Normalized Difference Vegetation Index (NDVI) data to derive SM using the Soil Evaporative Efficiency Model. The second approach employs Sentinel-1 backscatter coefficients, specifically at VV polarization, coupled with MODIS Leaf Area Index (LAI). These datasets areintegrated within a modified water cloud model, facilitating the derivation of the SSM product. This methodology exploits the sensitivity of Sentinel-1 radar backscatter to surface moisture variations and complements this information with LAI, ensuring a robust characterization of soil moisture content. A single algorithm has been devised to harmoniously integrate the two approaches, thereby yielding the temporal resolution within the range of 2 to 5 days. In the algorithm, on instances where the data modeling from the former approach encounters limitations by virtue of the scarcity of input datasets, recourse is sought through the latter approach. Such a sequential approach ensures a comprehensive and adaptable analytical framework, allowing for an increased spatial as well as temporal resolution of SSM datasets.
Solar influence on Millennial-scale variability of Indian Winter Monsoon during mid-late Holocene: Evidence from coastal sediments from Southeastern Sri Lanka 
Authors: Premaratne Kusala Madhushani , Chandrajith Rohana
Published: March 2024

Sun-climate connection is a well-documented expression of earth´s climate system. Higher sensitivity to solar forcing is evident in many paleoclimate records, ranging from decadal to millennial time scales. Considering the Indian monsoon domain, Summer Monsoon show asynchronous variations with energy output of the Sun throughout Holocene, however the response of its winter counterpart is not well understood. This study aims to explore the variability of the Indian Winter Monsoon in association with solar activity during Holocene. Monsoon reconstruction was based on trace elements and lanthanide geochemistry of lagoon sediments from south-eastern Sri Lanka.  A 5.1 m sediment core acquired from Pottuvil Lagoon was logged for concentrations of K, Rb, Mg, Al, Ti and rare earth elements at a 5cm interval using ICP-MS. The chronology of the core was established by Bacon 2.2 age-depth modelling based on calibrated AMS 14C dates. Reconstructed monsoon signal was compared with Holocene records of 14C and 10Be nuclide production rates which are considered as proxies for solar activity. Results revealed a distinct millennial scale variability of Indian Winter Monsoon during mid-late Holocene with three strong monsoon activity phases at 2553-2984 yrs BP, 3899-5021 yrs BP, and at 5244-5507 yrs BP. Further, the millennial-bands detected in Pottuvil monsoon record are closely matched with shifts in cosmogenic nuclide production rates, showing coherence with solar output. The existence of millennial scale variability is further reinforced by occurrence of dominant 1600 and 1000-year periodicities in Lomb-Scargle power spectra of element proxies. In particular, 1000-year periodic band is consistent with Eddy solar cycle. Thus, this study suggests a possible link to solar influence on millennial scale variability of Indian winter monsoon from mid to late Holocene.
A Novel Implementation to Simulate Basalt Segregation in the Hawaiian Mantle Plume Overcomes Model Limitations and Elucidates the Origin of the X-discontinuity
Authors: Monaco Martina
Published: March 2024

The X-discontinuity at 300 km beneath the Hawaiian hotspot has been hypothesized to require at least 40% basalt, a figure that would far exceed the plume's buoyancy and thus be irreconcilable with initial entrainments. We had previously explored the potential for large basalt accumulations to form over time by simulating a section of the plume conduit, with known quantities of basaltic material flowing in as discrete heterogeneities. For entrainments of 10-20%, we had estimated average accumulations of 20-25% at ~300 km depth. While this simplified setting recreated segregation of the denser material, it did not feature a realistic plume. On the other hand, employing mechanical mixture compositions hamper quantitative analyses of the recycled basalt.I have overcome this issue by developing a novel implementation to the ASPECT code. My advancement features a mechanical mixture composition (82% harzburgite — 18% basalt) for both the background mantle and the plume. The recycled material is then added to the self-consistent rising plume in the form of compositionally distinct basaltic heterogeneities. By combining these two approaches, I was able to successfully reproduce and quantify material segregation while keeping an accurate plume composition.Preliminary results, conducted in a 2000 km * 1000 km 2D domain, with entrainments of 10-20%, and a maximum resolution of 0.98 km in the heterogeneities, show average basalt accumulations of 20-22% around 300 km depth. Occasional, transient peaks at 31% and 35% can be observed for plumes incorporating 15% basalt. Over the model time (20 Ma), the denser material tends to sink between 360-660 km depth, generating large average accumulations of 35-40%. This new strategy not only opens promising scenarios by overcoming long-standing model limitations, but also reinforces the potential for mantle plumes to accumulate more denser material than classically thought, shedding further light on the controversial link between the X-discontinuity and the Hawaiian plume activity.