bluuebunny/crossref_metadata_2025 huggingface dataset:
Performing Quality Control on Meteorological Data Using Machine Learning Techniques
Authors: Spohn Teresa , O’Donoghue John , Horan Kevin , Charnecki Tim , Lally Conor , Haslam Merlin
Published: March 2024

Quality control (QC) on data has historically been a tedious and time-consuming task. With the currently available computer processing power and machine learning algorithms, it is possible to make QC far faster and more efficient, providing high-quality data in near real time to end users. Many organisations are already using such systems with great success, although the rapid expansion of machine learning continues to open new avenues for improvement. The aim of this project is to create a QC system for Met Eireann, the Irish Meteorological Office, which incorporates the latest machine learning techniques, combined with expert human supervision, to produce the highest possible quality meteorological data.Presented here are the ideas and concepts we intend to implement to create the QC system, showing the results of the initial trials on air temperature data. The project is still in the earliest stages of development and will benefit from input and feedback from others with experience working on similar projects.
Geothermal exploration in the Nemrut Caldera and surroundings (Eastern Anatolia-Turkey): Trying to unlock of geothermal potential in one of the world's largest calderas
Authors: Tut Haklıdır Füsun , Şengün Çetin Raziye , Görgülü İnci Selcen
Published: March 2024

Nemrut Volcano, which surfaces in the north of Bitlis province in Türkiye, is one of the most important active members of the Quaternary volcano sequence in Eastern Anatolia. According to historical records, the last volcanic activity in the region was in 1441 in the north of Nemrut Caldera and the basalt flows formed as a result of this volcanic activity caused Nemrut to be one of the last known active stratavolcano volcanoes in Turkey. It is possible to talk about a formation mechanism in which the intense tectonism in Eastern Anatolia is also effective.Nemrut Caldera, which has a surface area of approximately 36 km2, has a total of 5 lake formations, two of which are large, and Lake Nemrut is known as the second largest caldera lake in the world. Water temperatures in the lakes in the caldera vary between 16-41 0C. Hot water and gas outflows are observed in and around the caldera, which makes the region interesting for both geoscientists and geothermal energy investors. Due to the volcanic activity extending towards the north-east, there are hot water springs formed due to volcanism on the shore of Lake Van in the east of the region. The potential for geothermal energy applications in the region is still being investigated. In this context, the surface geology of the caldera and its surroundings was analysed and a series of hydrogeochemical investigations were carried out by taking samples from the hot and cold waters in and around the caldera and evaluating some critical elements. According to the results of chemical analyses and isotope analyses, since the hot-cold water mixture is intensely observed in the region, an exploration drilling to be carried out at the correct location in the region is also important in terms of understanding the reservoir levels and conditions.
Exploring the sediment redistribution dynamics of a data-scarce catchment in southwestern Ethiopia using the USPED model and gully erosion threshold indices
Authors: Yemane Haftu , Vermeulen Bart , Grum Berhane , Baartman Jantine , Hoitink Ton , van der Ploeg Martine
Published: March 2024

Soil erosion has on– and off-site detrimental effects, including decreased soil quality and sediment buildup in reservoirs. Predicting and monitoring soil erosion is challenging due to the spatio-temporal variation of its triggering factors. Therefore, developing and successfully implementing appropriate intervention measures requires a thorough understanding of its redistribution at the catchment scale. However, many previous soil erosion prediction models have been calibrated/validated based on sediment yield at catchment outlets. This approach does not provide any insight into the sources and sinks of erosion and deposition within the catchments. Furthermore, this approach has limited applicability in regions with no (limited) measured data. Therefore, exploring spatial patterns of erosion and deposition using the recent advances in remote sensing and GIS technologies is advisable. This research integrates the semi-distributed Unit Stream Erosion Deposition (USPED) model, and gully erosion threshold indices, described by stream power index (SPI) and topographic wetness index (TWI), to evaluate the sediment redistribution dynamics of a sub-humid catchment located in Omo-basin in southwestern Ethiopia. The catchment (~77 km2) has a rugged topography with an average slope of 35.8 %. It consists of four primary types of land use and cover (LUC): rangelands (20%), forest areas (19%), built-up areas (7%) and cultivated lands (54%). The (preliminary) results revealed that the gentle and mild slopes contribute more (53%) to the overall annual catchment soil loss (42.5 t.ha-1) from the hillslope. This is because the sediment deposited in the downstream sinks remobilizes, shifting an erosion-limited to a transport-limited system. Moreover, the total contribution of rangelands and forest areas is comparable to that of cultivated lands. Therefore, by focusing our management efforts on these areas, instead of the steeper slopes, we can make a greater impact on the overall sustainability of the catchment.
Detection of Immediate Foreshocks Using Dense Seismic Array: A Case Study of the 2021 Ms 6.4 Yangbi aftershock sequence
Authors: Ju Fengjiang , Meng Haoran , Chen Xiaofei , Yu Chunquan
Published: March 2024

Advancing our understanding of earthquake nucleation process can shed lights on earthquake prediction, early warning, and hazard assessment. Foreshocks, which usually refer to smaller earthquakes that occur before an earthquake, exhibit good temporal and spatial correlations with the mainshock. Investigating the relationship between foreshocks and mainshocks can therefore provide valuable insights into earthquake nucleation mechanisms and contribute to the improvement of earthquake prediction and early warning capabilities.
A recent study on the 2019 Mw 7.1 Ridgecrest earthquake sequence suggests that immediate foreshocks often share similar waveforms to the P-waves of subsequent earthquakes, differing only in amplitude. This similarity is believed to arise from the fractal nature of fault fracture processes. Consequently, there might be many immediate foreshocks with similar waveforms hidden in ambient noise that have gone undetected. Two methods have been proved to be effective in detecting small events: the Matched Filter Technique (MFT) and the Source-Scanning Algorithm (SSA). The MFT relies on template events to detect small events by stacking cross-correlograms between the waveforms of the templates and potential events. The conventional MFT, however, requires that the small events be located in the vicinity of one of the template events and does not provide the accurate locations of detected events. On the other hand, SSA is a migration-based approach that involves stacking non-negative waveforms, envelopes, and their extended characteristic functions. However, due to their tendency to provide absolute locations, SSA are heavily influenced by the accuracy of the velocity model and struggle to accurately detect earthquakes that are obscured by noise.
In our study, we prioritize the accuracy of relative event locations when studying the relationship between foreshocks and mainshocks. To address this concern, we have developed an advanced method that combines the strengths of cross-correlation and beamforming analyses. This method allows us to detect and relatively locate small seismic events simultaneously using dense array data. For the 2021 Ms 6.4 Yangbi  aftershock sequence, we first compute the cross-correlograms of the contentious records with the P-waves/S-waves of the target earthquake, respectively. We then grid searches around the hypocenter using N-th root stacking to detect and locate the immediate foreshocks. Upon detecting numerous immediate foreshocks, we proceed to statistically quantify the earthquake nucleation process or investigate the nucleation mechanism.
Long term response and adaptation of farmland water, carbon and nitrogen balances to climate change in arid to semi-arid regions
Authors: Li Yue , Herbst Michael , Chen Zhijun , Chen Xinguo , Xu Xu , Xiong Yunwu , Huang Quanzhong , Huang Guanhua
Published: March 2024

Climate change poses a challenge for resource utilization and environmental pollution issues caused by agricultural production, especially in arid to semi-arid regions. Farmland water, carbon and nitrogen (WCN) balances are closely related to these resource and environmental issues. Thus, the Agro-Hydrological & chemical and Crop systems simulator (AHC) was used to assess the response of WCN balances to climate change in a spring wheat farmland of arid Northwest China and to propose adaptation strategies. Five Global Climate Models from the Coupled Model Intercomparison Project 6 and two Shared Socioeconomic Pathways (SSP1-2.6 and SSP5-8.5) were used to establish scenarios with the AHC model to simulate farmland WCN balances for the 2025–2100 period. Various irrigation amounts and nitrogen fertilization rates were tested as compensation strategies. Results indicated that precipitation showed an increasing trend, thus percolation increased and soil water consumption decreased from 2025 to 2100. However, for the carbon budget, although the soil CO2 emissions tend to decrease, the net primary production (NPP) was also significantly reduced, which resulted in declining the net ecosystem carbon budget (NECB) under future climatic conditions. In addition, higher temperature and increased precipitation enhanced soil inorganic nitrogen leaching and N2O emissions but reduced NH3 volatilization from 2025 to 2100. Overall, the soil total nitrogen loss was increased over time, whereas crop nitrogen uptake (CNU) was significantly reduced. In relation to the SSP1-2.6 scenario, the SSP5-8.5 scenario accelerated the increase rates of soil water percolation and total nitrogen loss over time, as well as the decrease rates of CNU and NPP over time. The negative effects caused by climate change can be mitigated by reducing irrigation and increasing nitrogen fertilization. For the SSP1-2.6 scenario, 30% irrigation reduction and 30% nitrogen fertilization increase can effectively decrease soil water percolation and the related nitrogen losses while CNU, NPP and NECB increase in relation to the current management (240 mm irrigation and 200 kg ha–1 nitrogen fertilization). For SSP5-8.5 the strategy with 45% irrigation reduction and 45% nitrogen fertilization increase can also decrease nitrogen losses and increase CNU, NPP and NECB.
Minerogenic Salt Marsh Soil Responses to Increasing Rainfall Intensity and Soil CO2: Implications for Alkalinity Generation
Authors: Tutiyasarn Panunporn , Müller Peter , Romero Mujalli Gibran , Van Dam Bryce , Hartmann Jens , Porada Philipp
Published: March 2024

Salt Marshes and other vegetated coastal ecosystems play a crucial role in sequestering anthropogenic CO2 by storing carbon as organic matter within the ecosystem. Additionally, these ecosystems have been identified as potential hotspots for alkalinity generation, via anaerobic respiration and dissolution of carbonate minerals within sediments. In this way, they enhance the capacity of the ocean for CO2 removal. Quantitative insights into alkalinity generation at small scales, particularly those where rhizosphere processes and associated feedback take place, still remain limited. Our study addresses this gap by conducting a two-factorial lab-based column experiment coupled with water chemistry analysis to elucidate the influence of increased rainfall intensity and elevated soil CO2 levels on alkalinity generation in organic-poor minerogenic salt marsh soil. The results revealed a significant positive effect of increased rainfall intensity and elevated soil CO2 levels on alkalinity generation. Carbonate mineral dissolution was identified as the dominant driving force, with an additional dissolution of silicate minerals. Together, this study advances the understanding of rhizosphere environments characterized by relatively high CO2 levels as potential hotspots for alkalinity generation through mineral dissolution processes. Moreover, it indicates a clear association between intensified rainfall and heightened alkalinity generation, underlining an implication for future climate scenarios.
Smart boulders for real-time detection of hazardous movement on landslides
Authors: Newby Kate , Bennett Georgina , Roskilly Kyle , Sgarabotto Alessandro , Luo Chunbo , Manzella Irene
Published: March 2024

Landslides present a substantial hazard across coastal and mountainous regions in Europe and worldwide, and are becoming increasingly prevalent due to extreme rainfall linked to climate change. There is a need to develop new technologies for landslide monitoring and early warning systems, as traditional approaches alone are insufficient due to low temporal resolution and high costs. The SENSUM project (smart SENSing of landscapes Undergoing hazardous hydrogeologic Movement) has deployed manmade boulders, called SlideCubes, that monitor landslide movement in real-time across two coastal slow-moving landslide sites in southern England (Lyme Regis and Isle of Wight).SlideCubes are embedded with low-power low-cost sensors that comprise an inertial measurement unit (IMU with accelerometers and gyroscopes) and magnetometers. The SlideCubes are part of a wireless sensor network (WSN) that communicates via Long Range Wide Area Network (LoRaWAN) and Internet of Things (IoT) technologies. Rain gauges and other third-party sensors can be easily integrated into the network to provide additional data sources. Our novel WSN allows for near real-time wireless monitoring of the landslides, only requiring field visits to replace sensor batteries every 9-12 months. The sensors are motion-triggered, significantly saving battery power, meaning the WSN requires little and less frequent maintenance than other sensor-based monitoring approaches. This allows long-term remote measurement of landslide kinematics (inferred from SlideCubes) and initiation of movement, which is key for early warning.In the present work, initial findings from the SlideCubes installed at two UK-based sites are discussed. The movement events detected and recorded over 2 years are validated by periodic GNSS and drone imagery surveys. We present an overview of temporal and spatial motion across both landslide sites and evaluate sensor performance. Using gyroscope and accelerometer readings from field and laboratory data, we demonstrate how types of motion (e.g. rolling, sliding) can begin to be categorised, which is not possible with the accelerometer alone. This research will be developed in future with machine learning to detect hazardous movement including large magnitude catastrophic events. These findings will be integrated into a SENSUM early warning online portal, in development, for use by stakeholders.
Characterization of Evapotranspiration and effective precipitation in the Olive Areas of Extremadura, Spain. (1990-2021)
Authors: García Martín Abelardo , Paniagua Simón Luis Lorenzo , Honorio Guisado Fulgencio , Moral Francisco Jesús , Rebollo Francisco Javier , Aguirado Cristina , Rebollo Lourdes
Published: March 2024

The olive tree (Olea europaea L.) is one of the main woody perennial crops in Europe, especially in the Mediterranean area. The area dedicated to olive cultivation in the European Union (EU) has increased in the last decade, reaching 4.6 million hectares. Extremadura (Spain) is the region with a semi-arid Mediterranean climate located most south-west of Europe. It has a great climatological contrast in the North-South direction. Numerous studies indicate that an increase in temperatures and a reduction in precipitation is expected due to climate change in the Mediterranean region. This would cause an increase in crop Evapotranspiration and a lower contribution of rain, especially in dryland crops. Using time series of climate data (1990-2021), the differences between areas have been analyzed using an Anova and Tukey test. The trend of Evapotranspiration of the olive crop and annual effective Precipitation  in 13 olive-growing regions of Extremadura was also analyzed. To determine the monotonic trend, the Mann-Kendal test and Sen's slope estimator were used. The results showed clear differences between the olive-growing areas, for the analyzed indices. An increase in Evapotranspiration was found in important Olive-growing areas. However, the effective precipitation did not show any trend. These results contribute to the climatic characterization of the Olive-growing regions of Extremadura and could affect the yields and quality of production, requiring a varietal adaptation and cultivation techniques, as well as a change in the distribution of suitable cultivation areas.Keywords: Olive tree, Agroclimatology, Evapotranspiration, Extremadura
Beyond Extreme Temperature: Spatiotemporal Analysis of Humid Heat Stress 
Authors: Sojan Jency Maria , Srinivasan Jayaraman
Published: March 2024

Extreme humid heat stress presents significant challenges to human health and productivity. Traditional heat action plans formulated to tackle dry heat stress are insufficient to address the complexities associated with humid heat stress. Furthermore, there is limited quantitative evidence on the evolving patterns of humid heat stress under changing climate. This study investigates the spatiotemporal trends of extreme heat stress across the Global South from 1964 to 2023, distinguishing between dry and humid heat, using high-resolution ERA5 reanalysis hourly data and the Heat Index (HI).Notably, South Asia and the Middle East experience the highest frequency of extremely humid heat stress. Specific regions in peninsular South Asia have extremely humid heat stress hours from May to June due to persistent high humidity levels. In contrast, western regions of South Asia encounter extreme dry heat stress preceding the monsoon season, followed by a transition to humid heat stress immediately after the onset of the monsoon. The temporal analysis reveals a more rapid increase in the occurrence of extremely humid heat stress compared to that of dry heat stress from May to July over the past 60 years. This underscores the evolving nature of heat stress and the intensification of humid conditions compared to dry ones.In conclusion, this study advocates for a shift from exclusively addressing dry stress to a comprehensive approach that accounts for the diverse impacts of humid heat stress, particularly on vulnerable populations. This understanding is critical for policymakers to formulate adaptive strategies tailored to the changing landscape of extreme heat stress. 
Potential sources and transport of atmospheric microplastics in the North Atlantic Ocean
Authors: Evangeliou Nikolaos , Goßmann Isabel , Herzke Dorte , Held Andreas , Schulz Janina , Nikiforov Vladimir , Eckhardt Sabine , Gerdts Gunnar , Wurl Oliver , Scholz-Böttcher Barbara M.
Published: March 2024

The present study held in the frame of the JPI-Oceans FACTS examines the occurrence and long-range transport of microplastics (MP) in the North Atlantic Ocean. During a research cruise in 2021 seven transects along the Norwegian coast up to the Bear Island were actively sampled and the performance of two different sampling devices was evaluated. MP analysis and mass quantification was conducted using Py-GC/MS method. With careful reference to available field and laboratory blank values, MP was detected even in remote Artic areas with concentrations up to 37.5 ng MP m-3 and a clear predominance of the PET cluster. In addition, car tire tread, and clusters of PS, PP, and PUR were detected more often. Using the Lagrangian particle dispersion model FLEXPART, an attempt to reconstruct the origin of the air masses was made and to gain information about the origin of the measured MP by quantify different source contributions (sea-spray, mineral dust, road dust, agriculture). In this context, the resuspension of MP from the ocean into the overlying air layers appears to be a relevant source. Likewise, the long-range transport of PET particles appears to be substantial. The range of polymers detected, but also the risk of contamination, was closely linked to the particular sampling method used.
Determination of realistic uplift rate and noise assessment using GNSS coordinate time series
Authors: Karimi Hamed , Heydari Mahsa , Hugentobler Urs
Published: March 2024

The Earth deformation generally is divided into horizontal and vertical components. The vertical component has different behaviour and complexity caused by the tidal and non-tidal loading and other effects. In this contribution, the vertical motion rate of the Earth crust is considered and studied based on GNSS coordinate time series. The focus of this presentation is the signal processing algorithm applied to the time series. One of the challenges in signal extraction and data processing in the sequential steps is the error budget. The strategy which we considered in the uplift determination process after data-cleaning and outlier detection is to firstly detect the significant signals in the time series and the change points. Then, after removing the aforementioned signals e.g. annual, semi-annual, diurnal, tidal etc., the rate of the up component of the GNSS time series and the related uncertainty is estimated. To achieve this, we employed Monte-Carlo Singular Spectrum Analysis i.e. Monte-Carlo SSA for the signal detection process, Bayesian Estimator of Abrupt change, Seasonal change, and Trend (BEAST) for the change point detection, variance estimation algorithm e.g. LS-VCE, Allan variance etc. for noise characteristic determination and Least-Squares estimation for the estimation of uplift rate and the related uncertainty. In an overall view, in this contribution, the importance of realistic errors is highlighted to estimate the uplift rate and the related uncertainty e.g. as geophysical boundary value for mantle convection models.
Open questions regarding the influence of topography on the terrestrial water cycle
Authors: Gnann Sebastian , Baldwin Jane , Cuthbert Mark , Gleeson Tom , Schwanghart Wolfgang , Wagener Thorsten
Published: March 2024

Topography affects the distribution and movement of water on Earth, but exciting puzzles remain and new discoveries regarding topographic controls continue to surprise us. In this contribution, we discuss some open questions regarding the influence of topography on the terrestrial water cycle based on a combination of literature review and data synthesis. How will changes in water and energy supply along elevation gradients translate into changes in actual evaporation, and how will this be modulated by plant physiological responses and topographically driven moisture redistribution? What role does groundwater play in sourcing the world's water towers, and how will this role change with melting of snowpacks and glaciers? What is the relative importance of topography (vs. climate and geology) in driving groundwater flow dynamics across scales, and how does topography influence inter-catchment groundwater flow or mountain block recharge? A key feature emerging from these questions is the presence of numerous interacting gradients and contrasts that explain many of the patterns we observe. Studying these interactions, and thus answering at least some of the questions posed above, has the potential to improve our understanding of hydrological systems and how they may evolve in the wake of global change.
The value of functional relationships for large scale hydrology
Authors: Gnann Sebastian , Wagener Thorsten
Published: March 2024

We increasingly rely on complex models to understand the functioning and fate of our planet. But what hydrological theory underlies these models and thus the conclusions we draw from them? How do old and rapidly increasing new observations help to advance both theory and models? In this contribution, we discuss the importance of functional relationships for (large-scale) hydrology. We define functional relationships as relationships between two or more variables that characterize the functioning of hydrological systems, such as relationships between forcing and response variables (e.g. precipitation and runoff). Functional relationships are not only a central part of hydrological theory, but they also inform how we contextualize and make measurements, and they help us to build, constrain, and evaluate models. To illustrate their value, we first provide an overview of some relationships in large-scale hydrology. We then show how such relationships can be used to evaluate global water models. We conclude by discussing what our current state of knowledge can tell us about what we should explore next, in particular the need for mechanistic explanations of empirical relationships and the potential of linking multiple hydrological fluxes within a unified framework.
Earthquake Ground motion senarios for three cities in Bulgaria
Authors: Solakov Dimcho , Simeonova Stela , Raykova-Tsankova Plamena
Published: March 2024

Earthquakes are the deadliest of the natural disasters affecting the human environment, indeed catastrophic earthquakes have marked the whole human history. Global seismic hazard and vulnerability to earthquakes are increasing steadily as urbanization and development occupy more areas that a prone to effects of strong earthquakes. Additionally, the uncontrolled growth of mega cities in highly seismic areas is often associated with the construction of seismically unsafe buildings and infrastructures, that are undertaken with an insufficient knowledge of the regional seismicity and seismic hazard.The territory of Bulgaria represents a typical example of high seismic risk area in the eastern part of the Balkan Peninsula. Over the centuries, Bulgaria has experienced strong earthquakes. At the beginning of the 20th century (from 1901 to 1928) five earthquakes with magnitude larger than or equal to MS=7.0 occurred in Bulgaria. However, no such large earthquakes have occurred in Bulgaria since 1928, which may induce non-professionals to underestimate the earthquake risk. Bulgaria contains important industrial areas that face considerable earthquake risk. Moreover, the seismicity of the neighboring countries, Greece, Turkey, former Yugoslavia and Romania influences the seismic risk in Bulgaria.The assessment of seismic hazard and generation of earthquake scenarios is the first link in the prevention chain and the first step in the evaluation of the seismic risk. The use of earthquake scenarios in combination with modern methods of seismic engineering can reduce, to a great extent, the damage and casualties from a strong earthquake.In the present study deterministic and probabilistic earthquake scenarios for the cities of Sofia, Plovdiv, Varna, Ruse and Veliko Tarnovo are presented. The basic approach used for the creation of ground motion maps incorporate in GIS mode the source-geometry, earthquake occurrence model, the strength of the earthquake sources, and the appropriate attenuation relations.Earthquake scenarios are a powerful tool to support disaster management decisions. Successful preventive measures and planning of post-earthquake activities are based on scenarios of expected damage, destruction and casualties from predicted strong seismic impacts. The implementation of the earthquake scenarios into the policies for seismic risk reduction will allow focusing on the prevention of earthquake effects rather than on intervention following the disasters.
How dust sources affect downstream regions in East Asia during a dust storm event
Authors: Li Yanyu , Wu Qizhong
Published: March 2024

Dust storms are severe and disastrous weather events that typically occur in arid and semi-arid desertification areas. The frequent occurrences of spring dust storms in East Asia in recent years have drawn widespread attention in the context of the significant achievements in ecological management and sand prevention. Identifying the source and transport of dust storms in East Asia is key to comprehending the ecological environment and climate. In this study, the MODIS annual product MCD12C1 is used as labels to classify the land cover of Landsat 8/9 images using the Random Forest method in order to obtain the dynamic distribution of dust source areas. The land cover results are processed to the WRF model to provide the meteorological field, after which a Lagrangian transport model FLEXPART-WRF is used to simulate the horizontal and vertical transport of particles from five dust source regions in East Asia during the March 22, 2023 dust storm event. The source apportionments for regions on the transmission path of different dust sources are revealed by an online tracer-tagged of air quality model NAQPMS. The results show that the total area of the East Asian dust source regions in March 2023 is 1.5×106 km2. Cold high pressure from Siberia and the Mongolian cyclone are key synoptic situations for dust emission and transport from dust source areas. The Taklimakan Desert and the Tarim Basin mainly affect northwestern China. The Badain Jaran Desert and Horqin Sandy Land have a greater impact on northern China, with longer transmission distances, and can even affect southeast and Northeast China. The Gobi Desert affects northern China by influencing the dust source areas in Inner Mongolia. The vertical transport height is up to 500m from the ground. The PM2.5 source apportionments show that the Badain Jaran Desert contribution of Beijing-Tianjin-Hebei and its surrounding areas accounted for 45.5 %, while the Gobi Desert accounted for 1.4 %.
Probing large paleoenvironmental variability of Mediterranean during the Miocene-Pliocene transition via advanced multivariate statistical analysis on lipid biomarker multiproxy.
Authors: Pilade Francesco , Licata Michele , Vasiliev Iuliana , Birgel Daniel , Dela Pierre Francesco , Natalicchio Marcello , Mancini Alan , Mulch Andreas , Gennari Rocco
Published: March 2024

The quantitative reconstruction of paleoclimatic and paleoenvironmental conditions in regions and in time periods characterized by recurrent and significant fluctuations is challenging. An example of strong paleoenvironmental change occurred in the Mediterranean Basin across the Miocene – Pliocene boundary (5.33 Ma), marked by the restoration of normal marine conditions after the 'Lago-Mare' terminal phase of the Messinian salinity crisis. Environmental conditions during the Lago-Mare phase are still uncertain due to the controversial body fossil record, consisting of freshwater to brackish assemblages (ostracods, dinocysts, mollusks, and foraminifera), as well as marine microfossils (otoliths of marine fishes, calcareous plankton).However, two scenarios were suggested to describe this transition: 1) a catastrophic and sudden sea level rise causing the drastic change from freshwater to marine deep environments; 2) a gradual sea level rise, characterized by a fast to gradual transition from brackish to marine environments.To quantify the changing conditions during the Miocene–Pliocene transition, we used a multivariate statistical approach to interpret a large array of terrestrial and aquatic molecular-based indices, in a sedimentary succession of the Northern Mediterranean (Maccarone section, Central Italy). The statistical procedure was specifically developed to address the complexities emerging from the heterogeneous dataset.An illustrative example suggests that using the TEX86, UK37’, and MBT´5ME paleothermometers, we obtained different values and trends in the changing Mediterranean during the study interval. While the study acknowledges the validity of UK37’ as a paleothermometer in variable environments, it highlights that TEX86and MBT´5ME are sometimes compromised by other sources, such as reworked sediment or other organisms that produce the same lipid inventory. In these cases, these proxies provide information about environmental processes rather different than temperatures.Cluster analysis supports a stepwise evolution during the Miocene-Pliocene transition, besides redundancy analysis (RDA) indicates that the water column structure changed from stratified (Tetrahymanol) during the Messinian to mixed during the Zanclean. A second gradual change is instead related to terrestrial vegetation modifications, indicating a gradual coastal environment reconfiguration after a marine transgression with the distancing of the costal line and  a reduction of wetland aquatic plants signal. Finally, molecular fossils are also influenced by cyclical changes, not related to the Messinian salinity crisis demise but linked to astronomical-driven climatic cycles.
Synoptic and Mesoscale Conditions of Deep Moist Convection during the Cold Season in Croatia
Authors: Telišman Prtenjak Maja , Dolički Domagoj , Mikuš Jurković Petra , Jelić Damjan
Published: March 2024

In this study, thunderstorm activity during the cold part of the year was analyzed based on Thunderstorm Intensity Index (TSII) data on a pre-defined grid with a resolution of 3 km x 3 km in Croatia. The study covered a five-year period from 2016 to 2020, focusing on the months from October to March. The goal of the research was to conduct a spatial and temporal analysis of thunderstorm activity and determine the synoptic and thermodynamic conditions under which it occurs. The analysis aimed to provide an overview of the fundamental characteristics, thereby improving the understanding of deep moist convection in the cold part of the year, which poses a significant challenge in operational forecasting due to its lower frequency and more difficult intensity assessment. The occurrence of surface frontal disturbances was detected based on surface and upper-level synoptic charts, and the flow regime at the 500 hPa level was determined. Thermodynamic and kinematic parameters were calculated from radiosonde profiles from stations in San Pietro Capofiume, Brindisi, Pratica di Mare, Zagreb, and Zadar, using the thundeR free software package.        A total of 290 convective days were selected for analysis from the observed period. The results indicate that synoptic forcing plays a significantly greater role in the development of convection during the cold part of the year compared to the warm part, while the dominant upper-level flow regime is southwest. The obtained values of CAPE (Convective Available Potential Energy) in the cold part of the year are much lower than those in the warmer part, with a significant contribution from the considerably lower amount of solar surface heating. Additionally, most thunderstorms developed under conditions of strong vertical wind shear, indicating that the atmospheric environment conducive to winter thunderstorms is predominantly a High Shear-Low CAPE (HSLC) environment.
A global Lagrangian eddy dataset based on satellite altimetry 
Authors: Liu Tongya , Abernathey Ryan
Published: March 2024

The methods used to identify coherent ocean eddies are either Eulerian or Lagrangian in nature, and nearly all existing eddy datasets are based on the Eulerian method. In this study, millions of Lagrangian particles are advected by satellite-derived surface geostrophic velocities over the period of 1993–2019. Using the method of Lagrangian-averaged vorticity deviation (LAVD), we present a global Lagrangian eddy dataset (GLED v1.0). This open-source dataset contains not only the general features (eddy center position, equivalent radius, rotation property, etc.) of eddies with lifetimes of 30, 90, and 180 days, but also the trajectories of particles trapped by coherent eddies over the lifetime. We present the statistical features of Lagrangian eddies and compare them with those of the most widely used sea surface height (SSH) eddies, focusing on generation sites, size, and propagation speed. A remarkable feature is that Lagrangian eddies are generally smaller than SSH eddies, with a radius ratio of about 0.5. Also, the validation using Argo floats indicates that coherent eddies from GLED v1.0 exist in the real ocean and have the ability to transport water parcels. Our eddy dataset provides an additional option for oceanographers to understand the interaction between coherent eddies and other physical or biochemical processes in the Earth system.
New insights into the atmospheric dust dynamics in the Carpathian and Wallachian Basin during MIS 1-MIS 2
Authors: Perić Zoran , Alexanderson Helena , Marković Slobodan , Radaković Milica , Krsmanović Petar , Ryan Cathal
Published: March 2024

Fine-grained windblown deposits, known as loess, in which fossil soils (palaeosols) are preserved, serve as excellent records of past climate. However, paleoclimate reconstruction studies on loess-palaeosol sequences (LPS) in Southeastern Europe have primarily focused on climate changes during the last one or two glacial-interglacial cycles. Surprisingly, little attention has been given to the climate of the current interglacial, the Holocene. This oversight may be attributed to the prevailing notion that, based on ice core and marine isotope records, the Holocene is considered a climatically stable period. Additionally, the scarcity of LPS with well-preserved Holocene loess has contributed to this lack of attention until now. Three recently discovered loess-palaeosol sequences in the Eastern Carpathian and the Wallachian Basins present fully preserved loess covering MIS 1-MIS 2 offering the potential to unveil new and detailed information about Holocene climate. In this study, we present initial results from two of these LPS: Kisiljevo (44°44′0'' N and 21°25′0'' E) in the Carpathian Basin, and Velika Vrbica (44°35’1.70’’N, 22°43’15.97’’E) in the Wallachian Basin. For both sequences, detailed optically stimulated luminescence (OSL) chronologies using 63-90 µm quartz have been constructed. Age models based on the OSL ages were constructed using the r.bacon software (Blaauw & Christen, 2011), following which dust accumulation rates (MAR) for the last approximately 30,000 years were calculated. The initial results from Kisiljevo reveal a significant loess accumulation during the Holocene, amounting to approximately 120 cm. The highest MARs were observed between 10 and 12 ka (10,000-8,000 BC) with a mean value of 148 g m2 a-1. A similar trend is evident at the Velika Vrbica LPS, where the average calculated MARs during the early Holocene (8 – 11.7 ka) were 189 g m2 a-1, showing a decreasing trend toward the later part of this period (3.1 – 8 ka) with average values reaching 132.1 m2 a-1. Interestingly, at this site, the mean MARs during Marine Isotope Stage 1 (MIS) were higher than during the cold, stadial MIS 2, where the recorded values averaged 177 g m2 a-1. These initial results suggest that the Holocene dust dynamics in this region was more variable than what generally accepted models suggest.References: Blaauw & Christen (2011). Flexible paleoclimate age-depth models using an autoregressive gamma process. Bayesian Analysis, 6(3), 457–474.
Full-waveform tomography for the lithospheric structure of southern Tibetan Plateau
Authors: Zhu Qiwen , Fuji Nobuaki , Zhao Li
Published: March 2024

The collision of the Indian and Eurasian plates has resulted in high-altitude Tibetan Plateau with active seismicity. In this study, we apply the seismic box tomography to the southern Tibetan Plateau, aiming to obtain a self-consistent and high-resolution (10−20 km) model of the crust and upper mantle beneath the region, including density as well as bulk and shear moduli without a priori constraints, which provides us with crucial constraints on the compositional and thermal structures of a highly deformed lithosphere in southern Tibetan Plateau.In order to obtain the seismic tomographic model, we perform full-waveform inversion of teleseismic (30°−90°) surface- and body-wave waveforms recorded by the Hi-CLIMB network, a densely distributed (5−10 km station spacing) N-S oriented linear seismic array deployed during 2002 and 2005. In our iterative hierarchical inversion workflow, we calculate the sensitivity kernels based on the adjoint method and the model is updated by the L-BFGS algorithm. Data covariance matrices are introduced to control the data quality and objective weighting functions for different seismic events. We will present our preliminary results of the on-going study with comparison to existing models.
A new approach to modeling the time-space variations of ionospheric electric currents and magnetic fields during the September 2017 geomagnetic storm
Authors: Fillion Martin , Alken Patrick , Egbert Gary , Maute Astrid , Lu Gang , Pham Kevin
Published: March 2024

The study and modeling of Earth’s ionospheric electric currents and of the associated magnetic fields is fundamental for geomagnetic field modeling, and for the study of ionosphere coupling with the neutral atmosphere and the magnetosphere. Ionospheric electric currents, which exist during both quiet and disturbed geomagnetic activity periods, can be studied using magnetic field measurements from ground magnetic observatories and satellites. Modeling these currents during geomagnetic storms is particularly challenging due to the limited data available combined with high time-space variations during such events. In this study, we propose a new approach to modeling the storm-time ionospheric electric currents and magnetic fields. The approach relies on a joint utilization of magnetic data and the physics-based Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM). The TIEGCM time-space variations are first analyzed using a toroidal-poloidal decomposition of the magnetic field. To extract a priori information on the 3D spatial structure of the ionospheric magnetic field, principal component analysis is next applied to the spherical harmonics coefficients to obtain a small number of spatial modes that represent a substantial amount of magnetic field spatial variations. Temporal variations are represented by temporal modes computed with ground observatory data following Egbert et al. (2021). The entire procedure can be carried out in the frequency domain to account for induced fields. Spatial and temporal modes can be combined to parametrized the magnetic field measured by the Swarm satellites and the model coefficients estimated by solving an inverse problem. We present preliminary results obtained with this approach for the geomagnetic storm of September 2017.
Bridging time scales for comprehensive ETAS modelling to accommodate short-term to long-term incompleteness of seismicity catalogues
Authors: Kamranzad Farnaz , Naylor Mark , Lindgren Finn
Published: March 2024

Earthquake catalogues, vital for understanding earthquake dynamics, often grapple with incompleteness across varying time scales. Our research pioneers an innovative strategy to seamlessly integrate time-varying incompleteness into the Epidemic-Type Aftershock Sequence (ETAS) model. Leveraging the Bayesian prowess of inlabru package in R programming language, which is based on the Integrated Nested Laplace Approximation (INLA) method, we not only capture uncertainties but also forge a robust bridge between short-term to long-term gaps in records of earthquakes.Our methodology, a fusion of the ETAS model and inlabru, provides a comprehensive framework that adapts to diverse scales of incompleteness. We address the complex nature of seismic patterns by considering both short-term gaps in early aftershocks (minutes to a few days) and long-term irregularities (years to centuries) in historical earthquake data records. Technically, the short-term incompleteness period arises from seismic network saturation during periods of high activity, resulting in the underrecording of small events, while the long-term incompleteness originates from sparse network coverage and inability to detect events over extended time. Bayesian foundation of inlabru enriches the model with posterior distributions, empowering us to navigate uncertainties and refine seismic hazard assessments. By utilising a combination of simulated synthetic data and real earthquake catalogues, our results showcase the impact of this approach on the ETAS model, markedly improving its predictive accuracy across various temporal scales of incompleteness.In this study, we present an initiative in seismicity modelling that bridges temporal gaps, allowing the ETAS model to evolve with the ever-changing landscape of earthquake data incompleteness. This research not only enriches our understanding of spatiotemporal seismicity patterns but also lays the groundwork for more resilient and adaptive aftershock forecasting, ultimately equipping decision-makers with more reliable information about seismic hazards, and enhancing community resilience in the face of earthquakes.
The weakening AMOC under extreme climate change
Authors: Madan Gaurav , Gjermunsen Ada , Iversen Silje C. , LaCasce Joseph H.
Published: March 2024

Changes in the Atlantic Meridional Overturning Circulation (AMOC) in the quadrupled CO2 experiments conducted underthe sixth Coupled Model Intercomparison Project (CMIP6) are examined. Increased CO2 triggers extensive Arctic warming,causing widespread melting of sea ice. The resulting freshwater spreads southward, first from the Labrador Sea and then theNordic Seas, and proceeds along the eastern coast of North America. The freshwater enters the subpolar gyre north of theseparated Gulf Stream, the North Atlantic Current. This decreases the density gradient across the current and the currentweakens in response, reducing the inflow to the deepwater production regions. The AMOC cell weakens in tandem, firstnear the North Atlantic Current and then spreading to higher and lower latitudes. This contrasts with the common perceptionthat freshwater caps the convection regions, stifling deepwater production; rather, it is the inflow to the subpolar gyre thatis suppressed. Changes in surface temperature have a much weaker effect, and there are no consistent changes in local orremote wind forcing among the models. Thus an increase in freshwater discharge, primarily from the Labrador Sea, is theprecursor to AMOC weakening in these simulations.