bluuebunny/crossref_metadata_2025 huggingface dataset:
Significant change in the flow regime in the deep Southern Ocean through the MPT
Authors: Rückert Eva M. , Frank Norbert
Published: March 2024

The deep Southern Ocean (SO) circulation is of major significance for the understanding of the ocean´s impact on Earth’s climate as uptake and release of CO2 strongly depend on the redistribution of well and poorly ventilated water masses.Neodymium isotopes (εNd) preserved in deep sea sediment have proven useful to study the Deep Ocean Circulation and water mass provenance and are of special interest over major climate changes as the Mid Pleistocene Transition (MPT). The MPT marks the change from a 41 ka to a 100 ka glacial-interglacial cyclicity and goes along with a significant intrusion of southern sourced waters (SSW) in the deep North Atlantic.Here, we present the first millennial resolved authigenic εNd data in the Southern Atlantic spanning across  the MPT of a deep sea sediment core positioned at the polar front. The pre-MPT εNd values of ODP 1093 show a small variability of approx. 2 ε-units around the modern AABW signature of -8. In contrast, the post-MPT εNd variability increases to 6 ε-units with glacial extremes of around -3 – εNd values that can not be found in any Atlantic sourced water mass today!This supports not only the exsiting hypotesis of stonger SSW export to the North, but rather advocates for a radiogenic  watermass influencing the flow regime in the Atlantic south of the polar front. Increasing ice volume during post-MPT glacials has been argued to lead to a reduced AABW production. Due to continuity of flow, this opens up the possiblity of glacial intrusion through the Drake passage of a water masses likely originating in the Pacific, which would generate  the strongly radiogenic glacial εNd values. At present Pacific deep waters are enriched with respired carbon. Assuming this to hold true in the past, the intrusion of such carbon rich water masses into the deep South Atlantic could further reinforce the strong glacials and the overall global cooling trend after the MPT as suggested previously.Hence, the SO south of the polar front played a leading role in  reinjecting respired CO2 into the deep Atlantic Ocean and the Atmosphere during climate transitions. 
Hypothetical measures on high-level radioactive waste from the perspective of extended interim storage and final disposal
Authors: Bracke Guido , Maerten Lena , Borkel Christoph
Published: March 2024

The site selection for a repository for high-level radioactive waste (HLW) will take longer than the currently authorised period of 40 years for interim storage sites in Germany. Extension of this period could necessitate additional handling or measures, such as treatments of HLW. This might have an impact on radionuclide mobility in the final repository. Therefore, BASE initiated a research project that studied the behaviour of HLW in interim storage was studied for causes of degradation, effects and consequences and possible treatments, performed by GRS gGmbH. There are currently no indications for mandatory measures during the authorized period and beyond, but some hypothetical treatments were identified. These treatments were evaluated with regard to their impact on interim storage, radiation exposure for personal, manageability and radionuclide mobility in repositories. Measures include, for example, heating and earlier removal from interim storage for conditioning. Even though technical feasibility was not part of the study, it seems clear that with any of the identified measures, higher radiation doses would have to be expected for the personnel. The impact of these measures on radionuclide mobility in the repository is assessed to be low. However, a more quantitative assessment of the impact of hypothetical treatments appears only feasible when a repository concept including waste acceptance criteria is fixed, which is not the case at the time of the study.
Climate of the eastern Mediterranean and Middle East in the 6th century CE with COSMO-CLM 
Authors: Hartmann Eva , Xoplaki Elena , Wagner Sebastian
Published: March 2024

The climate of the eastern Mediterranean and the Middle East is well documented in natural (speleothems, tree rings, sediments and pollen) and human-historical archives. The 6th century CE is of particular interest from both a historical and climatic perspective. It is a period of prosperity for the Eastern Byzantine Empire and political stability, but also a time when there was a heavily debated plague pandemic and significant climate variability associated with a major cluster of volcanic eruptions. Dynamical downscaling can bridge the gap between palaeo-records and climate reconstructions, which can be affected by various sources of uncertainty, and the coarsely resolved Earth System Models (ESMs) with 200 km or more horizontal resolution. A transient paleo-simulation with the appropriately adjusted regional climate model COSMO-CLM (CCLM, COSMO 5.0 clm16) is carried out to investigate possible links and feedbacks between the socio-political and economic conditions and the climate variability of that period in more detail.The state-of-the-art and CMIP6 compliant forcing reconstructions of volcanic (stratospheric aerosol optical depth), orbital (eccentricity, obliquity, precession), solar (irradiance), land-use and greenhouse-gas changes used for the MPI-ESM-LR (Jungclaus et al. 2017) are therefore implemented in the regional climate model. The simulated temperature and precipitation are compared with those of other CMIP6 models as well as with proxy records and reconstructions. In connection with the two successive volcanic eruptions in 536 and 540 CE, the annual temperature of the entire region dropped noticeably until about 550 CE. The signal for precipitation is not as clear, but the years of the eruptions are the driest of the century in the eastern Sahara and Arabian Peninsula and the wettest in the eastern Mediterranean.
LSPIV analysis of large wood effect on the direction and velocity of surface flow in meandering river
Authors: Kapustová Veronika , Galia Tomáš , Sedláček Pavel , Kovaříková Andrea
Published: March 2024

Large in-channel wood, typically present in meandering rivers, serves as an obstacle in the water course, affecting hydraulics of the water flow. It is an important but so far overlooked agent in river morphodynamics. One of the challenges in predicting the hydraulic impact of large wood is the scarcity of field data; this issue is typically explored through laboratory flume experiments. To analyse the effect of large wood on the distribution and velocity of water flow we conducted LSPIV analysis on selected channel segments of meandering Odra River (Czechia). Large Scale Particle Image Velocimetry (LSPIV) is a remote image-based technique, enabling monitoring of the direction and velocity of surface flow in a river channel segment. LSPIV employs a method of tracking surface particles visible in sequential images extracted from video recordings of river water levels. These recordings are captured from an aerial perspective, either oblique or vertical. For our study, we utilized UAV to record 30-second vertical video segments of river sections during periods of both low and high discharge. Additionally, we implemented ground control points and reference scales along the river banks to enhance the accuracy and scale of our measurements. For the LSPIV analysis, we used free Fudaa-LSPIV software (INRAe). As we anticipated, our findings indicate that the impact of large wood on surface flow is contingent on two primary factors: the size of the wood and its position within the channel. However, we observed that this effect significantly varies across different flow stages. We observed that large wood effectively redirects water flow. According to its position in the channel cross-section, it is either preventing the erosional banks from lateral erosion, or accelerating the flow towards the bank and supporting lateral erosion. As discharge increases and large wood becomes submerged, its effect diminishes. During low discharges, stabilization effect of large wood is more important, creating calm water areas and supporting sediment accumulation. Our research offers a comprehensive framework for advancing the qualitative and quantitative evaluation of the hydraulic and morphodynamic effects of large wood in meandering rivers. Such insights are crucial for guiding sustainable river management and informing river restoration projects.
Nano to milli scale characteristics of wolframite ([Fe,Mn]WO4)  and their implications for U-Pb geochronology of tungsten-bearing mineral deposits
Authors: Carr Patrick , Romer Rolf , Chew David , Wirth Richard , Mercadier Julien
Published: March 2024

Geochronological data on ore-bearing minerals can constrain the absolute ages and duration mineralising processes. Of the tungsten-bearing minerals, wolframite is the most promising geochronometer for these mineral systems, but high precision ages are hampered by common Pb and intra-grain heterogeneity. We present ID-TIMS and LA-ICP-MS U-Pb isotope data of wolframite , combined with milli scale (SEM-EDS) and microscale (LA-ICP-MS) element maps and nanoscale (FIB-TEM) chemical and structural images to elucidate the complex geochemical behaviour of this mineral and the implications for U-Pb geochronology.During this study, three new U-Pb reference materials have been developed with ages of ca 158 Ma, 289 Ma and 325 Ma; these are available to interested laboratories. The best precision obtained by ID-TIMS was 1.24%, whilst we estimate the best possible precision for LA-ICP-MS ages to be ca 1.8%. Apart for analytical uncertainties, the main contributor to age uncertainty is the poor dispersion in U-Pb data (for Discordia fitting) and unknown common Pb composition for ID-TIMS data, and micron-scale heterogeneity for LA-ICP-MS data.Microscale (LA-ICP-MS maps) to nanoscale (FIB-TEM) imaging techniques show large chemical and structural heterogeneity of wolframite related to the complex geological environments in which it is precipitated and altered. Trace element mapping highlights oscillatory and sector zoning not typically observed when using traditional SEM-based techniques. The variable distribution of the analysed elements (Fe, Mn, Sc, Nb, Ta, Y, Pb, Th and U for this study) can be explained both by coupled substitution and changing fluid chemistry recorded within a single wolframite crystal. The nano-scale structure of a strongly altered wolframite is characterised by rare ca 10x10 nm non-symmetric zones of amorphous crystal structure, and bands of elongate (ca 100 x 20 nm oval-shaped) low density zones that we consider representing porosity developed during rapid crystallisation of wolframite.Although no real intra-grain age dispersion is observed in the analysed samples, the precision of U-Pb ages is strongly affected by the local chemical and structural characteristics of the wolframite. Most notably, the concentration of 238U and 238U/204Pb can vary by an order of magnitude within a zone smaller than a typically laser ablation spot (e.g., 100 µm). 
Modelling secondary ice production in Arctic mixed-phase clouds
Authors: Raatikainen Tomi , Calderon Silvia , Järvinen Emma , Romakkaniemi Sami
Published: March 2024

Ice number concentration is a critical parameter for Arctic mixed-phase clouds. Several observations have shown that such relatively warm clouds can have orders of magnitude higher ice concentrations than expected based on typical Ice-Nucleating Particle (INP) concentrations. The most common explanation is that Secondary Ice Production (SIP) such as rime splintering (Hallett-Mossop ice multiplication) process causes the increase in ice concentration. Here we use observations from two field campaigns. In both campaigns the observations indicated that one or more SIP processes were actively producing ice. Due to the high temperatures around 265 K, the focus is on Hallett-Mossop process. Observed meteorological conditions and aerosol size distributions were used to initialize high-resolution large-eddy model UCLALES-SALSA simulations. Primary ice formation was modelled based on fixed INP concentrations so that the observed ice concentration was at least ten times larger than the INP concentration. Hallet-Mossop ice multiplication factors due to rime-splintering did not reproduce observed rates of secondary ice production. An increment of about one order of magnitude was needed to find agreement between modeled and observed ice number concentrations. This highlights the urgent need of laboratory and model studies that unveil the variable dependencies controlling SIP mechanisms. Secondary ice production can be increased by adjusting the simulated cloud temperature towards the optimal value and by increasing cloud water content. Extending simulation time up to 10 hours or more will also help. Although high ice concentrations can be obtained simply by increasing the INP concentrations, details such as vertical ice distribution and spatial variability will be different than in the case where SIP is used. Although this difference has a small impact on cloud dynamics during these 10-hour simulations, long-term impacts are likely.
Modeling the impact of Hurricane Maria on Puerto Rico with an eco-hydrological landslide model
Authors: Arnone Elisa , Soylu Evren M. , Takahiro Furuya , Bras Rafael L.
Published: March 2024

This study proposes an advanced hydrologic/landslide modeling application to assess the spatial distribution of rainfall-induced landslides for a sub-basin in central Puerto Rico. The framework implements a stability component into a spatially distributed physically-based hydrological model coupled to a model of plant physiology. Puerto Rico is an ideal study site to assess the performance of landslide modeling efforts due to the availability of thousands of catalogued landslides triggered by Hurricane Maria (HMA) during September 19-22, 2017. The main objective of the study is to simulate the observed landslide events forcing a coupled eco-hydrological-stability model, the tRIBS-VEGGIE-Landslide, with weather data of HMA. The tRIBS-VEGGIE-Landslide model has the advantage of accounting for the vegetation dynamics that affect the soil moisture patterns at an hourly scale and for the soil-water characteristic curve and the saturated shear strength parameters (cohesion and friction angle) to assess the factor of safety (FS) in space and time, using an infinite slope model.The modeling application focuses on two small sub-basins of the Rio Saliente watershed, each smaller than 1 km2. The small study area allows for the use of a 5m DEM resolution topography, which has been derived from a 1m resolution LiDAR measurements. Since many radar and ground stations were destroyed during the hurricane, the hourly time series of the HMA event has been reconstructed by using the NCEP (National Centers for Environmental Prediction) – Environmental Modeling Center (EMC) gridded Stage IV data, produced by NOAA National Weather Service. The precipitation data resulted in a maximum hourly intensity of 64.52 mm/hr, maximum daily intensity of 294.56 mm/day, and rainfall total of 332.15 mm, consistent with other daily reconstructions. Preliminary results demonstrate the importance of the spatial computational mesh and accurate characterization of soil parameters, which play an essential role in simulating landslides with mechanistic models.
Distinguishing between different sources of recharge in a complex binary karst aquifer: a case study of the Unica springs (SW Slovenia)
Authors: Kogovšek Blaž , Jemcov Igor , Petrič Metka
Published: March 2024

The characteristics of groundwater flow and solute transport in karst aquifers differ considerably from those in intergranular and fissured aquifers. To understand how they function, appropriately adapted hydrogeological research techniques and analyses are required. In this study, a binary karst aquifer in the recharge area of the Malenščica and Unica springs, which covers an area of about 820 km2 in southwestern Slovenia, was selected as the study area. A monitoring network was set up to obtain data on precipitation and discharge at the two springs, two sinking streams and two water-active caves in their catchment over a period of two hydrological years. First, a classical approach of correlation and spectral analysis of these time series data was applied to determine and compare the flow characteristics and storage capacity of selected springs and their recharge areas. The allogenic and autogenic recharges were considered separately as input functions and the results of the analysis were compared. Although these widely used methods provided a good characterization of the studied karst system, the interpretation can be ambiguous due to the interference of the two input components. To avoid this problem, an innovative method of partial cross-correlation analysis was used, which has previously only been applied to separate the influence of different precipitation stations in karst. Here, its application was extended to the evaluation of the influence of allogenic recharge. By controlling the input parameters precipitation and discharge of one of the sinking streams, it was possible to determine the contribution of the other sinking stream to the observed spring. The differences in the recharge characteristics of the Unica and Malenščica springs were revealed, and the ability of this innovative approach to provide additional insights into the functioning of binary karst aquifers was confirmed. Key words: karst aquifer, autogenic and allogenic recharge, time series analysis, partial cross-correlation, Slovenia.
Impact of Climate Change and Terrestrial Water Storage on the Himalayan Seismicity 
Authors: Malakar Sukanta , Rai Abhishek K.
Published: March 2024

The Himalayan terrain epitomises continuing convergence and geodetic deformation caused by tectonic and non-tectonic factors. Climate change and induced secondary factors are some of the dominant non-tectonic forces. A small change in stress and pore-fluid pressure caused by precipitation and temperature fluctuations may trigger seismic activity in the vicinity of already critically stressed faults and fractures at local and regional scales. The increase in temperature has also resulted in the melting of mountain glaciers in the Himalayan region and the release of the glacial load, leading to post-glacial rebound and elastic deformation. This study investigates the correlation and causal relationship between climatic parameters and earthquakes in the Himalayas. Further, we study the hydrological loading effect (derived from the GRACE/GRACE-FO satellite) and correlate it with the seismic hazard map. The results show that temperature anomalies have a relatively strong influence (r ~0.36-0.54) on the occurrence of minor-magnitude earthquakes in the Eastern Himalayas. However, the North-western Himalayas show a moderately positive correlation with precipitation anomalies (r ~0.23-0.37). Furthermore, a positive correlation has been found between regional terrestrial water storage (TWS) influence and the seismic hazard, ranging from 0.04-0.45. The result shows higher positive correlation values in the post-monsoon period for the North-western and Eastern Himalayas, whereas the Central Seismic Gap and Eastern Nepal and Sikkim show a higher value for the pre-monsoon period.
Multi-Technique Analysis and Landscape Evolution: Implications for Landslide-Fluvial Cascading Hazards Assessment
Authors: Guinau Marta , Fernández-Jiménez Celeste , Barra Anna , Viaplana-Muzas Marc , Flores Ariadna , Ortuño Maria , González Marta , Pinyol Jordi , Abancó Clàudia
Published: March 2024

The interaction between slope instability processes and river dynamics often triggers a cascade effect. Sediment influx from slopes can obstruct rivers, leading to upstream flooding and potential catastrophic flash floods downstream upon dam breakage. In addition, the incision of the drainage network steepens the valley hillslopes, further exacerbating slope instability processes, modifying the geomorphology and the sedimentary fluxes and increasing the occurrence of landslide-derived hazards.In this regard, a comprehensive and updated landslide inventory, especially focusing on the interconnection between landslides and drainage networks, is crucial for effective hazard assessment considering these cascading effects induced by slope and fluvial processes.This study presents advancements in landslide mapping by integrating data from Multi-Temporal Synthetic Aperture Radar (MT-InSAR) and landscape evolution analysis through geomorphological indices such as Chi, Normalized Channel Steepness Index (Ksn) and Stream Length-Gradient Index (SL). Identification of anomalies along rivers using Ksn and SL (knickpoints or knickzones) aided in pinpointing abnormal slopes due to sediment influx from landslides. Additionally, active areas were delineated using the ADAfinder tool, extracting data from MT-InSAR provided by the European Ground Motion Service (EGMS). This multi-technique analysis highlighted the slopes of interest. Landslides identified with these techniques were delimited and characterized in terms of type assignment, using 2x2 m DTM hillshades derived from airborne LiDAR data and field observations.The upper catchments of the Garona and Noguera Pallaresa rivers (central Pyrenees-NE Spain) were selected as study cases. The study highlights the disequilibrium in the watershed divide between Noguera Pallaresa and Garona basins, suggesting a transition toward equilibrium favouring a main divide migration towards the Noguera Pallaresa due to hillslope processes. The assessment of the equilibrium profile geometry of the Noguera Pallaresa river at a regional scale suggests at least two main knickpoints. The river sections downstream of the knickpoints are associated with landslides triggered by post-glacial dynamics and incision wave effects. Combining SL and Ksn curves with Active Deformation Areas (ADA) underscores areas with potentially reactivating deep-seated landslides, signifying potential high damages in case of low-probability but catastrophic reactivations.In conclusion, the integration of diverse methodologies shed light on the spatial relationship between transient features in the landscape (knickpoints) and landslide occurrence, emphasizing the need for a comprehensive approach to mitigate landslide and fluvial risks in the Noguera Pallaresa and Garona river basins.
The role of emergency management in times of water stress – The need for adaptation
Authors: Carbon Danielle , Wenzel Till
Published: March 2024

Climate change threatens profoundly the quality and quantity of groundwater  resources. Extreme precipitation patterns and existing hydrospheric basins are likely to change. Today, in some regions a significant decline in surface and groundwater reservoirs can already be observed. Rather than solely relying on reactive adaptation measures during water scarcity emergencies, governments have the responsibility to develop proactive and preventative strategies through an effective emergency management.
However, some emergency measures such as the emergency drinking water supply or wildfire response require the permanent availability of regional surface and groundwater. Among other things, emergency drinking water management is mainly based on the extraction and treatment of surface water (e.g. mobile via tanker lorries) and groundwater (e.g. static via emergency wells).
The results of the NASA programme GRACE indicate that, in particular, regions where surface water has already declined significantly due to prolonged periods of drought tend to substitute groundwater. Concerns are raised that such substitution can further increase regional affectedness by further reducing the local water availability. 
In a comprehensive review of 79 documents dealing with the exemplary management of drinking water emergencies in Germany, it became clear that currently the synergy between emergency measures and water resources are not sufficiently reflected.
The study analysed publications by the German Technical and Scientific Association for Gas and Water (DVGW), the Federal Office for Civil Protection and Disaster Assistance (BBK), the Federal Agency for Technical Relief (THW), the fire and rescue services and the German Red Cross (DRK).
The main objective was to identify gaps in the emergency management strategies including questions such as: To what extent regional water shortage and the resulting specific challenges for emergency management are currently addressed? And in turn, which impacts arise from the emergency management for water resources?
The results reveal that existing strategies are not tailored to the specific conditions of water stressed regions, as they neither address the damage or failure of the intended emergency structure (e.g. drying out of emergency wells) nor the protection of local water resources through further water abstraction. As a conclusion, emergency management should be integrated into a more holistic water management in an interdisciplinary approach. In doing so, regional water stress can be mitigated while at the same time the emergency management remains effective in face of future need.
Further work will include an EU-wide survey on how different emergency stakeholders involved in water-intense disaster management consider cascading effects of their measures and what GIS-based tools might support their decision making.
An attempt to model the accuracy of GNSS Positioning from GIPSY-X PPP-AR Referring to  JPL’s 2019 Experiment
Authors: Çetin Deniz , Sanli D. Ugur , Ogutcu Sermet
Published: March 2024

Multi-GNSS techniques are continuously improving themselves and strengthening their infrastructures. In response, companies producing GNSS hardware and software are enhancing their products with refined techniques, leading to improved positioning precision. In line with these advancements, efforts are being made to enhance algorithms which predict the accuracy of GNSS positioning. Following these improvements, users who conduct field works or optimize networks would want to know about the improved accuracy of GNSS positioning. After GPS, the new members of the GNSS are continually improving their infrastructure. To achieve the desired coordination in terms of a common processing ground among these techniques remains a challenge. This is particularly crucial for organizations developing GNSS software. For instance, NASA JPL has been making efforts to produce a PPP-AR solution. The transition from GIPSY OASIS II to GIPSY-X allowed for the processing of combined GPS, GLONASS, and GALILEO data in a JPL experiment in 2019. However, today, there is yet no AR infrastructure for the combined solution of all techniques beyond the float solution. In this study, we investigated whether JPL's 2019 AR solution is still applicable to current research. Initial attempts yielded promising results as we conducted experiments with 50 points from the IGS MGEX network's shared data. By comparing the differences between the 2019 PPP-AR solution and the 2019 and 2023 float solutions, we found that the discrepancies are not significantly large in today's GNSS accuracy. We concluded that an accuracy model generated from the 2019 AR solution could provide a satisfactory estimate for today's users. Initial findings indicate that GPS performs well with the combination of three techniques, while the synergy of techniques significantly contributes to the improvement of the vertical positioning. The accuracy produced by the combination is witnessed to be dependent on the observation period, emphasizing the need for attention from those conducting campaign measurements in this context.
Urban soils as interdisciplinary archives of urban co-evolution – informing historical analysis and ecohydrological modelling: A case study of Gaußbergpark, Braunschweig, Germany
Authors: Gillefalk Mikael , Özgen-Xian Ilhan , Rickert Gregor , Weigl Fabian , Neber Anneke , Iden Sascha , Bücker Matthias , Martin-StPaul Nicolas , Neumann Franziska
Published: March 2024

Anthrosols and technosols are urban soils that have been heavily influenced by anthropogenic activities. We hypothesise that such soils store information that can give insights into the system's co-evolution. In a case study of the urban green space Gaußbergpark, Braunschweig, Germany, we demonstrate how an interdisciplinary study of anthrosols yields complementary data sets that provide a more complete picture of the processes involved in urban co-evolution. Gaußbergpark is a public park, located at the northern part of the historical city wall, close to the Oker river. The hill that constitutes the Gaußbergpark was heaped up as a part of the defensive fortifications built during the early modern period. After the abandonment of the fortifications, the area was temporarily used as a landfill during the 18th century before it became part of a band of parks and green areas in the early 19th century. We explore this area from a historical, geophysical, and ecohydrological perspective. In this contribution, we will discuss data from historical archives, geophysical measurements (ERT), and ecohydrological modelling paired with soil moisture observations. As an example, the geophysical measurements clearly showed differences in soil properties between the hilltop and the areas below the slopes. The hill containing mainly sandy soils (fill) while the surroundings contained silty and clayey soils (natural origin to be expected). Simultaneously, this information is valuable for both historical as well as ecohydrological analyses of the area. Our synthesis shows that key ecohydrological processes, such as transpiration, soil moisture dynamics, and runoff partitioning, depend on the specific geophysical properties of the underground, which in turn are explained through the area's history.
Strengthening the Bridge between Singapore and Norway: How Education Exchanges and Public Outreach are Applied in Climate Science
Authors: Yan Yu Ting , Toh Yun Fann , Paneiri Giuliana , Horton Benjamin
Published: March 2024

Universities have a critical role to play in the response and recovery from the climate crisis. As institutions, universities have been resilient to changes. This resilience supplies the human, intellectual, and financial capital to understand and address the major challenge of climate change. Singapore and Norway have education exchange programmes through various scholarship programs, research collaborations, and Erasmus+. In 2023, the third expedition of Advancing Knowledge of Methane in the Arctic (AKMA3) by the Arctic University of Norway (UiT) provided students from Singapore a platform to experience how offshore expeditions in the Arctic are conducted.On board the Norwegian Research Vessel Kronprins Haakon, Singapore students used state-of-the-art research facilities to help collect samples and data from extreme environments (cold seeps) from high-latitudes seafloor. Daily interactions with international experts of different backgrounds help us to better understand the various aspects of the scientific work related to the expedition and outreach efforts undertaken to promote Arctic science to the public.Here, we demonstrate how our learned experience in Norway can be applied to our research projects in Singapore. Despite the differences in geological location and polar and tropical climates, we strive to show how student collaboration can help build strength between the two countries. By highlighting the adaptability and transferability of acquired knowledge, this collaborative effort aims to transcend geographical boundaries and contribute to the global advancement of scientific understanding of climate change.
ULF waves in geospace and the challenge of estimating radial diffusion coefficients from in situ data.
Authors: Katsavrias Christos , Aminalragia-Giamini Sigiava , Thanasoula Konstantina , Nasi Afroditi , Papadimitriou Constantinos , Georgiou Marina , Balasis Georgios , Daglis Ioannis A.
Published: March 2024

Radial diffusion, driven by Ultra-Low Frequency (ULF) waves in the Pc4–5 band (2–25 mHz), has been established as one of the most important mechanisms that influences the dynamics of electrons in a quite broad energy range, as it can lead to both energization and loss of relativistic electrons in the outer Van Allen radiation belt. The same has been observed in other planetary magnetospheres. The dependence of ULF wave power spectral density and radial diffusion coefficients (DLL) on solar wind parameters has been investigated by some studies, but their relationship on the various solar and interplanetary drivers is far from well-studied and understood. In this study, we use the “SafeSpace” database (https://synergasia.uoa.gr/modules/document/?course=PHYS120), which contains radial diffusion coefficients and ULF wave power spectral density, and was created using magnetic and electric field measurements from the THEMIS satellites in the 2011–2019 time-period. We conduct an extensive statistical analysis of DLL in order to investigate the relationships between the magnetic and electric components as well as their dependence on interplanetary drivers (i.e. High Speed Streams and Interplanetary Coronal Mass Ejections). Our results reveal an energy dependence of the radial diffusion coefficients as well as significant variations of the DLL spectral profiles as a function of Roederer’s L*. Our findings highlight statistical, as well as physical, characteristics and aspects of DLL which are not included in most semi-empirical models typically used in radiation belt simulations, thus potentially introducing significant biases in the estimation of the outer belt relativistic electron environment. Further discussion will be devoted to the uncertainties of such efforts as well as the possible contribution of magnetosheath processes (e.g., jets and electron injections from the foreshock) and solar wind mechanisms (periodic density structures).The work leading to this paper has received funding from the European Union’s Horizon Europe research and innovation programme under grant agreement No 101081772 for the FARBES (Forecast of Actionable Radiation Belt Scenarios) project. 
Bias-corrected high-resolution temperature and precipitation projections for Canada 
Authors: Rajulapati Chandra Rupa , Abdelmoaty Hebatallah Mohamed , Nerantzaki Sofia , Papalexiou Simon Michael
Published: March 2024

High-resolution precipitation and temperature projections are indispensable for informed decision-making, risk assessment, and planning. Here, we have developed an extensive database of high-resolution (0.1°) precipitation, maximum, and minimum temperature projections extending till 2100 at a daily scale for Canada. We employed a novel Semi-Parametric Quantile Mapping (SPQM) methodology to bias-correct the Coupled Model Intercomparison Project, Phase-6 (CMIP6) projections for four distinct Shared Socio-economic Pathways. SPQM is simple, yet robust, in reproducing the observed marginal properties, trends, and variability according to future scenarios, and maintaining a smooth transition from observations to projected simulations. The database encompasses a substantial collection of 759 simulations derived from 37 diverse climate models for precipitation. Similarly, for maximum and minimum temperature projections, our database comprises 652 simulations from 30 climate models. These meticulously curated projections carry immense value for hydrological, environmental, and ecological studies, offering a comprehensive resource for analyses within these domains. Furthermore, these projections serve as a valuable asset for the quantification of uncertainties arising from variant labels, climate models, and future scenarios.
Northern African vegetation and land cover changes led to increased Arctic warming during the mid-Holocene
Authors: Tiwari Shivangi , Pausata Francesco S. R. , de Vernal Anne , Beltrami Hugo , LeGrande Allegra N. , Griffiths Michael L.
Published: March 2024

The mid-Holocene (MH) was characterized by substantial vegetation changes over northern Africa, termed the Green Sahara. Concurrently, several proxy reconstructions have indicated anomalous warmth over some Arctic regions during the MH, with some records also indicating an abrupt cooling coinciding with the Saharan desertification. This has prompted studies into a potential teleconnection between the MH Green Sahara and the Arctic, leading to conflicting hypotheses regarding the dominant direction and mechanism for this teleconnection.In this study, we analysed outputs from four fully coupled global climate models to identify the impact of the Green Sahara on the Arctic region. Through the difference of two sets of mid-Holocene simulations – with and without the Green Sahara – we isolated the effect of the northern African vegetation and land cover changes on Arctic temperatures. We show that simulations incorporating the Green Sahara yield considerably higher Arctic warming relative to simulations without explicit prescriptions of vegetation changes. We also conducted atmosphere-only global climate model simulations to identify whether or not Arctic temperature changes impacted northern African precipitation. Our results suggest that while the Arctic temperature changes induced changes to the atmospheric circulation over northern Africa, they were too weak to substantially contribute to Saharan desertification.
Understanding the dynamics of information diffusion through data-driven social network modeling for the 2012 U.S. drought and wildfire
Authors: Song Jiam , Kam Jonghun
Published: March 2024

Social network plays a critical role in risk communication diffusing information in near real time. Disaster-affected communities utilize their social network to report catastrophic damages and increase the perceived risk of the ongoing disaster by non-affected communities, which enhance their willingness to donate and support emergency aids to the affected communities. Previous studies have focused on social network structure or information diffusion separately. This study strives to reproduce the social response to natural disasters aims integrating the two aspects of social network structure and information diffusion. This study focuses on two classical and catastrophic U.S. disasters, such as 2012 flash drought and wildfire, to establish the social network during these two disasters and understand difference in the patterns of the risk communication within the data-driven social network and random social network (e.g., (the equal chance/importance of a nodes). Random social network is made from the LFR benchmark algorithm using the properties of the data-driven network, including node number, degree distribution, community distribution, and average degree. This study leverages over 120,000 (53,000) tweets that contains a term, drought (wildfire). In this study, a Susceptible-Infected-Recovered (SIR) model is employed to simulate the information diffusion patterns using the data-driven and random social network. After fitting SIR model with the Twitter data using these two social network-based simulations, this study aims to assess 1) the impact of the structure difference on risk communication and 2) the impact of influential users in different social network structures. Result shows that the trained SIR model using the data-driven social network reproduced the observed information diffusion patterns for the 2012 drought and wildfires but with relatively higher uncertainty in the information diffusion pattern for wildfires. The SIR model simulation with data-driven social network shows a faster information diffusion pattern with a higher information reach rate than that with the random social network. In closing, this study discusses limitations and opportunities of next-generation social dynamic modeling for natural disaster risk communication. This study highlights the value of an interdisciplinary approach in improving risk communication and developing a more efficient and effective mitigation policies for not only droughts and wildfires and other natural disasters.
GRDC-Caravan: extending the original dataset with data from the Global Runoff Data Centre
Authors: Färber Claudia , Plessow Henning , Mischel Simon , Kratzert Frederik , Addor Nans , Shalev Guy , Looser Ulrich
Published: March 2024

Large-sample datasets are essential in hydrological science to support modelling studies and global assessments. The Global Runoff Data Centre (GRDC) is an international data centre operating under the auspices of the World Meteorological Organization (WMO) at the German Federal Institute of Hydrology (BfG). Established in 1988, it holds the most substantive collection of quality assured river discharge data worldwide. Primary providers of river discharge data and associated metadata are the National Meteorological and Hydrological  Services of WMO Member States.As the awareness for open data and reproducibility has increased in recent years, GRDC is working to simplify data provision to its users and to comply with the FAIR (findable, accessible, interoperable, reusable) principles. GRDC data and products are accessible online for non-commercial use (https://grdc.bafg.de). However, there are still hurdles on the way to a completely open and free exchange of data such as restrictive data policies and a lack of data standardisation.Caravan is a community initiative to create a large-sample hydrology dataset of meteorological forcing data, catchment attributes, and discharge data for catchments around the world (Kratzert et al. 2023). Compared to existing large-sample hydrology datasets, the focus on Caravan is to use globally consistent forcing and attribute data to facilitate global studies. Additionally, Caravan provides the code to derive community extension on Earth Engine with as little as catchment boundaries and streamflow data required. The vision of Caravan is to provide the foundation for a truly global open source community resource that will grow over time.      This dataset is the 6th extension to the original Caravan data set. It is based on a subset of hydrological discharge data and station-based watersheds from GRDC, which are covered by an open data policy (Attribution 4.0 International; CC BY 4.0). The dataset covers stations from 5357 catchments and 25 countries, spans 1950 – 2023, and is already publicly available on Zenodo: https://zenodo.org/records/10074416 Reference:Kratzert, F., Nearing, G., Addor, N. et al. Caravan - A global community dataset for large-sample hydrology. Sci Data 10, 61 (2023). https://doi.org/10.1038/s41597-023-01975-w
Impact of magmatic intrusions on metamict zircon annealing as constrained by Raman spectroscopy in the eastern Adamello batholith (Central Alps)
Authors: Favaro Silvia , Resentini Alberto , Tiepolo Massimo , Malusà Marco Giovanni , Zanchetta Stefano
Published: March 2024

The impact of a magmatic polyphasic intrusion on the empirical relationship between zircon metamict state as revealed by Raman spectroscopy (Zhang et al., 2000) and α-damage accumulation of the same grains is investigated in the eastern Adamello batholith (Central Italian Alps). Eighteen samples, spanning the contact between the Val di Genova pluton, the Sostino-Corno Alto pluton, and their host rocks – including Permian intrusives, were examined.Zircons were analysed with a 100mW Nd:YAG solid state laser emitting at 532 nm Raman spectrometer to assess their metamict state based on the position and full width at half maximum of different Raman bands. For each zircon, on the same spot, LA-ICP-MS analyses were performed to determine the crystallization age and U, Th, and Pb concentrations. Crystallization ages and actinides content were used to calculate α-damage since zircon crystallization.Magmatic zircon ages display a south to north younging trend from the Sostino pluton (44.79±0.35 Ma) to the Val di Genova pluton (34.18±0.20 Ma), consistent with literature data (Schaltegger et al, 2009 and 2019; Ji et al., 2019 and references therein). Moreover, magmatic zircons from the Adamello batholith exhibit a metamict state roughly consistent with calculated α-doses, indicating nearly full retention of decay-related damage. In contrast, zircons from the Paleozoic country rocks and Permian plutons show a nearly crystalline state conflicting with calculated high α-doses, thus suggesting a thermal overprint that annealed their crystalline structure, here identified with the thermal aureole of the Adamello magmatic intrusions. In fact, the measured metamict state of zircons in the host rocks is in overall agreement with α-damage accumulation calculated since intrusion rather than crystallization ages.Raman analysis of radiation damage in zircon is being currently investigated as a new thermochronological method (Pidgeon, 2014; Nasdala et al., 2001; Nasdala et al., 2002; Hartel, 2021) with particular emphasis on unannealed zircons to test its feasibility. With this study, we present an application of Raman analysis of radiation damage in annealed zircons to trace their thermal history, thus providing independent validation of contact-metamorphic overprints.
High-resolution kinematic study of the Late Mesozoic to Late Cenozoic seafloor spreading at the Central Mid-Atlantic Ridge.
Authors: Granot Roi , Gaina Carmen
Published: March 2024

The Central Atlantic oceanic crust documents the evolution of seafloor spreading along the Central Mid-Atlantic Ridge. Previous works have identified marine magnetic anomalies (i.e., isochrons) every ~7 Myr for the pre-Neogene time, thus, the existing Nubia-North America plate kinematic models suffer from rather crude temporal resolution. Here, we present preliminary results from a detailed plate kinematic investigation aiming to reconstruct the kinematics of seafloor spreading at ~1.5 Myr time intervals. Our model is constrained by ~11000 identifications of 40 magnetic reversals younger than C34y (83.6 Ma) and older than C6no (19.7 Ma). We also investigated the fracture zones using multibeam bathymetry and satellite-derived gravity data. These identifications are confined by the Fifteen-Twenty fracture zone in the south and the Azores triple junction in the north. We invert these identifications and fracture zone crossings to estimate a set of finite rotation poles and stage rotations. We confirm the validity of our plate kinematic solutions by comparing a set of synthetic flowline tracks to the location of fracture zone traces. Based on these new poles, we present a detailed kinematic analysis that sheds new light on the evolution of the Central Atlantic since the Late Mesozoic. 