bluuebunny/crossref_metadata_2025 huggingface dataset:
CFC-11 and CCl4 in the Atmosphere: A free calibration standard for Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS)
Authors: Holzinger Rupert , Notø Hanne Ødegaard
Published: March 2024

The Proton-transfer-reaction mass spectrometer (PTR-MS) has become an important tool for real-time monitoring of volatile organic compounds (VOCs) in the atmosphere. PTR-MS is semi-quantitative in untargeted analysis if the transmission of the analytes is well constrained. The transmission at different m/z is determined by using commercial calibration standards.We present an additional method to constrain the instrument transmission using well-monitored ozone-depleting substances in the atmosphere. Ozone-depleting substances such as chlorofluorcarbons (CFCs)  are banned and monitored through the Montreal Protocol, but their concentration in the atmosphere is relatively stable, and due to their long lifetime they are well mixed. Two of these banned substances can be detected using PTR-MS, namely Trifchloroluoromethane (CFC-11) and carbon tetrachloride (CCl4). Their major ion CCl3+ is measured at m/z 116.906. A clear signal at this mass is observed in all atmospheric measurements. Since the concentrations of CFC-11 and CCl4 in the atmosphere are measured frequently by global monitoring networks, they can be used to determine the transmission at m/z 116.906. We experimentally determined the pseudo-reaction rate constants of CFC-11 and CCl4. Utilizing this, the transmission of m/z 116.906 can be determined using any atmospheric measurements in the past or present. This innovative approach can be a useful tool for quality control of PTR-MS data and checking instrument performance during measurements.
Water column methane dynamics at an abandoned well (southern North Sea, sector A15)
Authors: Delre Annalisa , Mienis Furu , de Bruin Geert , Velzeboer Ilona , Verstaijlen Noortje , de Haas Henk , Engelmann Julia , Reichart Gert-Jan , Niemann Helge
Published: March 2024

The coastal ocean is highly dynamic and typically rich in methane, which is produced in sediments by microbial or thermogenic processes. In the North Sea subsurface methane is commercially exploited; once a gas field is exhausted the extraction wells are sealed with concrete. Despite this precaution, these wells may leak, becoming a potential source of methane, which might reach the atmosphere. There are several thousand abandoned wells in the North Sea, but the amount of methane escaping from these and the further fate of this methane including microbial methane oxidation and liberation to the atmosphere are not well constrained. We investigated methane dynamics at an abandoned well in the Dutch sector of the North Sea (A15-3), using a combination of different sampling and investigation tools. We conducted continuous in situ measurements of water column methane concentration, currents and various other physicochemical parameters using a bottom lander (ALBEX). Furthermore, temporally replicated hydro casts were carried out to resolve methane concentrations, vertically. We also recovered discrete water samples to investigate aerobic methanotrophs and associated methane oxidation rates, both vertically and over time. First results show an elevated background methane level of about 30 nM – yet, we recorded several events of high methane concentration reaching up to 300 nM for a duration of 10 - 60 minutes. Intervals of elevated water column methane concentrations and methane oxidation rates were also found during hydro casts. We will discuss these data in relation to environmental forcing factors including tidally induced current and hydrostatic pressure changes, as well as biological factors such as the methanotrophic community dynamics.
Temperature at 500hPa, energy budget and the 2003 summer heatwave over Western Europe: a triple-decomposition approach
Authors: Fossa Manuel , Danaila Luminita , Ghil Michael
Published: March 2024

Heatwaves represent a major health hazard, as was the case for the 2003 summer heat wave, responsible for more than 70 000 deaths in western Europe. The interplay of mean flow, quasi-periodic and random fluctuations — associated with the westerly jet, Rossby and gravity waves, and eddies — of the large-scale temperature field results in complex heat wave–related amospheric conditions. Understanding how the different physical processes interact is thus crucial for prediction of heat wave events. In this study, we use the triple decomposition of turbulent flow (Hussain and Reynolds, JFM, 1972) to compute mean, quasi-periodic and random energy fluctuations of the temperature field, that is the 1-point energy budget of temperatures. This decomposition takes into account all interactions between the zonal jet, Rossby waves, gravity waves, and eddies. Both spectral and dynamical systems analyses are applied to the computed terms. More specifically, the concept of extremal length (Ahlfors, Vol. 371, AMS, 2010) is integrated into the equations to quantify how each term of the energy budget equations contributes to the "trapping" of temperature anomalies over Europe.      Results show that, amid positive sea surface temperatures and negative soil moisture anomalies, during the first half of August, i.e., the hottest days of the heat wave, quasi-periodic oscillations of polar air increased, resulting in meridional migration of cold air over Canada, and subsequent mixing with warmer air coming from North America. This mixing triggered baroclinic instabilities that led to production of turbulent eddies, which by August 5th suddenly stopped their eastward progression, creating a cyclonically stalled regime over the Mid-Atlantic; this stationary cyclone interacted positively with North African warm air propagating northward over Europe, thus sustaining the dry conditions over France and much of Western Europe. The cyclonic block finally disappeared, stopping the warm air advection from North Africa, with temperatures falling just after that. The study reveals that interactions between quasi-periodic and random processes of production, diffusion and dissipation of a scalar field’s energy play an important role in the evolution of a major heatwave. Hence, the 2003 event was not just the result of a superposition of Rossby waves and eddy anomalies. Extremal length analysis thus reveals that the zonal advection of temperature anomalies was blocked by interactions between quasi-periodic and random production and diffusion processes. This study highlights the complex turbulent interactions that lead to major heat wave events, and the fact that each such event is thus unique.
Exploring potential nonlinear developments of snowline depletion in a changing climate in Austria
Authors: Günther Daniel , Koch Roland , Olefs Marc
Published: March 2024

The seasonal snow cover is of great interest in Austria due to its immense importance for numerous economic, ecological and social sectors. Meteorological conditions, expressed as the snowline altitude determine whether rain or snow falls on the ground. If the intensity of precipitation is sufficiently high and there is little atmospheric mixing, the melting of solid precipitation in valley areas can lead to a cooling of the atmosphere and to a further drop in the snowline altitude – the snowline depletion effect.  In the course of a changing climate, an increase in snowline altitude is predicted. However, these predictions do not consider the described effect of snowline depletion. From the theory, the increase of the snowline has nonlinear consequences for the frequency and intensity of the subsequent depletion effect. In this study, we investigate this effect for Austria during past precipitation events on the basis of station observations and gridded now-casting products, develop and test a simplified parametrization, and subsequently show its potential future evolution based on simulations.
Quantifying Turbulent Mixing in Plunging River Inflows: Insights from Field Measurements in Lake Geneva
Authors: Thorez Stan , Lemmin Ulrich , Barry D. Andrew , Blanckaert Koen
Published: March 2024

Hyperpycnal river inflows discharging into lakes or reservoirs will plunge and trigger gravity-driven underflows near the bed. Such underflows are called turbidity currents if the density excess is mainly caused by a high sediment concentration. These underflows can reach the bottom of the lake or, alternatively, detach from the bed and intrude horizontally into the lake waters to form an interflow if a layer of equal density is encountered. As underflows carry a number of constituents fed to them by the river or eroded from the bed, such as sediment, contaminants, nutrients and oxygen, their pathway and final destination have an impact on lake or reservoir water quality. The mixing processes in the plunging region are known to be of dominant importance for the dilution of the inflowing river water by entrainment of ambient water, thereby exerting a primary control on the final intrusion depth of underflows. Understanding and quantifying these processes is therefore key. Until now, the majority of estimations of the mixing extent in the plunging region were made within laterally confined laboratory experiments or via passive tracer methodologies. This study focuses on quantifying plunging mixing from flow velocity measurements in a laterally unconfined river inflow in the field and investigating its dependency on inflow conditions.Field measurements of the plunging Rhône River entering Lake Geneva were conducted using a boat-towed ADCP along a grid of transects for six inflow conditions characterized by the inflow densimetric Froude number Frd. The plunging mixing coefficient Ep, which compares the underflow discharge immediately post-plunging to the initial river inflow discharge, was used to quantify the plunging mixing.Results indicate that for larger Frd values (Frd > 4) Ep estimates align with laterally confined lab experiments (Ep = O(0.1)). Conversely, for smaller Frd values Ep estimates correlate with field tracer measurements of laterally unconfined inflows (Ep = O(1)). Ep decreases with increasing Frd, challenging existing numerical simulations predicting the opposite relationship.This study offers key insights into turbulent mixing rates associated with hyperpycnal river inflows and highlights the need to incorporate realistic field conditions for accurate modeling of plunging river inflows and intrusion depth.
Uncertainties in climate sensitivity and residual carbon emissions permit for a hothouse climate ahead
Authors: Kaufhold Christine , Willeit Matteo , Talento Stefanie , Ganopolski Andrey
Published: March 2024

Given the large ‘very likely’ range of equilibrium climate sensitivity (ECS, 2 to 5 K), as reported by the Intergovernmental Panel on Climate Change (IPCC) and additional carbon cycle feedbacks, we investigate whether the current Earth system has the potential to significantly deviate from pre-industrial levels in the long-term towards a “hothouse” state. We use the fast Earth system model CLIMBER-X to generate an ensemble of simulations for the next millennium with interactive CO2 and CH4 for ECS values between 2 and 5 K, and force our simulations using the extended low-to-intermediate emission scenarios of SSP1-2.6, SSP4-3.4, and SSP2-4.5. These scenarios are normally associated with peak global warming levels of 1.5, 2, and 3°C respectively for a standard ECS of approximately 3 K.In simulations using an ECS of 5 K, we observe that the global mean temperature increase would more than double compared to the standard ECS of 3 K. Roughly half of this warming is propelled by positive carbon cycle feedbacks in the different scenarios, with equal contributions from both CO2 and CH4. In the SSP2-4.5 “middle of the road” scenario, we find that a high ECS could see global mean temperatures which exceed 7 °C within the next millennium, with some regions experiencing temperature increases up to 20 °C via polar amplification. If we consider unavoidable residual carbon emissions of less than 10% of our present-day value, we find that the CO2 concentration in the atmosphere can be sustained, thereby resulting in a continuous temperature rise until the year 3000 A.D. unless carbon is sequestered. Prolonged periods of high temperatures, as seen in this study, could lead to the breaching of critical thresholds within the Earth system, like the stability of the Greenland and Antarctic ice sheets for example. As high ECS values cannot be disregarded as implausible at the present time, these results hint hint that we could be on track towards an extreme “hothouse” climate in the long-term if there is no carbon removal.
Evaporation driven by Atmospheric Boundary Layer Processes over a Shallow Salt-Water Lagoon in the Altiplano
Authors: Hartogensis Oscar , Aguirre Correa Francisca , Suárez Francisco , Lobos-Roco Felipe , Ronda Reinder , Vilà-Guerau de Arellano Jordi
Published: March 2024

The Chilean Altiplano is a region composed by endorheic basins immersed in a complex topography. These basins are predominantly characterized by desert surfaces in which small-scale heterogeneities can be found in the form of salt flats with shallow, salt water lagoons, that act as preferential pathways for evaporation (E). Thus, understanding the processes that control E in the lagoons is essential for water balance predictions, and to understand the impacts of climate change on the region.In addition to the local saline lagoon and desert conditions, the atmospheric boundary layer (ABL) and its interaction with large-scale forcing, play a key role in regulating E. Observations over a salt water lagoon in the Salar del Huasco basin show that in the morning E is virtually zero, with turbulence as a limiting factor due to the absence of wind. Under these conditions, a shallow, stable ABL is formed over the water. In the afternoon, E is triggered by the entrance of a thermally driven and topographically enhanced regional flow characterized by strong winds. Simultaneously, the ABL turns into a deep mixed layer similar to the one observed over the surrounding desert.In this research we investigate the coupling between the ABL and E drivers using a land atmosphere model, observations and a regional model. We also analyze the ABL interaction with the aerodynamic and radiative components of E using the Penman equation adapted to salt water. Our results demonstrate that the morning ABL is controlled by the local advection of warm air (∼5 Kh-1), resulting in a shallow (
A catalogue of large solar energetic particle events observed by Solar Orbiter for the first ~ four years of measurements (2020–2023)
Authors: Papaioannou Athanasios , Rodríguez-García Laura , Gomez Herrero Raul , Lavasa Eleni , Kouloumvakos Athanasios , Vasalos George , Warmuth Alexander , Richardson Ian G. , Lario David , Zouganelis Ioannis , Espinosa Lara Francisco , Cernuda Cangas Ignacio , Kuel Patrick , Schuller Frederic , Barczynski Krzysztof , Fleth Sebastian , Anastasiadis Anastasios , Walsh Andrew , Mueller Daniel , Rodriguez-Pacheco Javier ,   A Solar Orbiter Team
Published: March 2024

Solar Orbiter (SO) observations provide an unprecedented opportunity to study the evolution of solar energetic particle (SEP) events from different locations within the heliosphere. In this work, we have compiled a catalogue of SEP events based on observations of both electrons and protons from the High Energy Telescope (HET) of the Energetic Particle Detector (EPD) that occurred in 2020 to 2023 during the ascending phase of Solar Cycle 25. A scan of simultaneous So/HET intensity-time observations for ~10 MeV protons and near relativistic (~1 MeV) electrons has been performed. We have identified all enhancements observed above the background levels of these particular channels and surveyed available solar wind data by the SO/ Solar Wind Analyzer (SWA) and the SO/Magnetometer (MAG) during the identified events. Moreover, we employed Velocity Dispersion Analysis (VDA) for protons and electrons and Time-shifting Analysis (TSA) for electrons, alone, with the aim to infer the SEP release times at the Sun. Our resulting catalogue includes 75 SEP events. For each of these events (and for each species), we provide the onset and peak time, the peak flux value and fluence. We also identify the solar associations/sources for the SEP events, by comparing the inferred release times of the SEPs to the related light curves from the SO/Spectrometer/Telescope for Imaging X-rays (STIX), the standard flare list obtained from the GOES X-ray Sensor and their associated coronal mass ejections (CMEs). We find that a significant portion of all SEP events in our sample (48%; 36/75) reached 50 MeV for protons and thus are Space Weather relevant. Finally, a statistical analysis of our observations is presented. We have investigated correlations between peak particle fluxes (for protons and electrons) and event fluences, as well as peak particle fluxes (event fluences), flare magnitude and CME speed. We also calculate the connection angle to the apparent source and identify a subsample of the events that are better connected to the solar event. In addition, the e/p ratio is calculated and a division of the sample based on Fe-rich and 3He-rich events is discussed. Acknowledgement: Research leading to these results has received funding from the Horizon Europe programme project No 101135044 (SPEARHEAD).
Interpretation of Pandora NO2 measurements over Beijing and application to satellite validation
Authors: de Leeuw Gerrit , Liu Ouyang , Li Zhengqiang , Lin Yangyan , Fan Cheng , Zhang Ying , Li Kaitao , Zhang Peng , Wei Yuanyuan , Chen Tianzeng , Dong Jiantao
Published: March 2024

A Pandora spectrometer has been installed on the roof of the laboratory building of the Aerospace Information Research Institute of the Chinese Academy of Sciences in the Olympic Park, Beijing, China, in August 2021. The concentrations of trace gases (including NO2, HCHO, O3) measured with Pandora are made available through the open-access Pandora data base (https://data.pandonia-global-network.org/Beijing-RADI/Pandora171s1/). The Beijing-RADI Pandora is included in the data suite which is routinely used for TROPOMI S5P validation. The use of Pandora total and tropospheric NO2 VCDs for validation of collocated TROPOMI data, resampled to 100×100 m2, shows that although on average the TROPOMI VCDs are slightly lower, they are well within the expected error for TROPOMI. The location of the Pandora instrument within a sub-orbital TROPOMI pixel of 3.5×5.5 km2 may result in an error in the TROPOMI-derived tropospheric NO2 VCD between 0.223 and 0.282 Pmolec.cm-2, i.e., between 1.7% and 2%. In addition, the data also show that the Pandora observations at the Beijing-RADI site are representative for an area with a radius of 10 km.The Pandora total and tropospheric NO2 vertical column densities (VCDs) and surface concentrations collected during the first year of operation show that NO2 concentrations were high in the winter and low in the summer, with diurnal cycle where the concentrations reach a minimum during day time. The concentrations were significantly lower during the 2022 Winter Olympics in Beijing, showing the effectiveness of the emission control measures during that period. The Pandora observations show that during northerly winds clean air is transported to Beijing with low NO2 concentrations, whereas during southerly winds pollution from surrounding areas is transported to Beijing and NO2 concentrations are high. The contribution of tropospheric NO2 to the total NO2 VCD varies significantly on daily to seasonal time scales, i.e., monthly averages vary between 50% and 60% in the winter and between 60% and 70% in the spring and autumn. The comparison of Pandora-measured surface concentrations with collocated in situ measurements using a Thermo Scientific 42i-TL Analyzer shows that the Pandora data are low and that the relationship between Pandora-derived surface concentrations and in situ measurements are different for low and high NO2 concentrations. Explanations for these differences are offered in terms of measurement techniques and physical (transport) phenomena.
Reservoir and seal characterization of deep marine sediments using seismic facies analysis with machine learning techniques
Authors: Feyzullayev Tural , Lubo-Robles David , Benjumea Beatriz , Bedle Heather , Llave Estefanía , Javier Hernández-Molina Francisco , Lin Ng Zhi
Published: March 2024

This work describes key aspects of the methodology for subsurface characterization of Late Miocene deep marine sedimentary systems of the Gulf of Cádiz. In particular, we focus on the products of alongslope bottom currents processes, known as contourite systems, and mixed deposits developed by the interaction between contourite and downslope turbidite systems. Both these systems offer prospects for CO2 storage for their high reservoir potentials. In addition, hemipelagic sediments and fine-grained contourites present in the area could act as seals. The objective of this study consists of using seismic attributes and machine learning techniques for conducting a seismic facies analysis to distinguish between various Late Miocene deep marine deposits in a 3D seismic volume. The first step is to restrict the dataset to the deposits of interest in order to avoid irrelevant sediments or structures such as the allochthonous unit of the Gulf of Cádiz or salt domes or diapirs. This adjusts the dynamic range of the clustering to focus on our targets. The second step is the testing of the seismic attributes to improve their selection criteria, in order to maximize the differences between the distinct seismic facies. Finally, we apply an unsupervised clustering algorithm for the selected seismic attributes to perform an automatic seismic facies analysis that facilitates both reservoir and seal imaging. This study will ultimately help to assess the socio-economic impact of Late Miocene sediments developed by bottom currents on climate change mitigation and energy transition. This research and the Grant PRE2022-102745 were funded by MCIN/ AEI/10.13039/501100011033 and they are linked to the ALGEMAR project (PID2021-123825OB-I00). This work is partly supported by SEASTORAGE project (TED2021-129816B-I00), funded by MCIN/ AEI/10.13039/501100011033/PRTR-C21 and by the European Union NextGenerationEU.
Warming of Northern Peatlands Increases the Global Temperature Overshoot Challenge
Authors: Zhu Biqing , Qiu Chunjing , Gasser Thomas , Ciais Philippe , Lamboll Robin D.
Published: March 2024

To meet the Paris Agreement temperature goal, allowable carbon emissions in the future are tightly limited. It is very likely that the 1.5°C temperature limit will be at least temporarily exceeded (overshoot) under an emission pathway following current climate policies and actions. Peatlands store large amounts of soil carbon, the destabilization of which could potentially cause large amplifying feedback on global warming. Using the reduced-complexity Earth system model OSCAR v3.1.2 and a new peat carbon module, we assessed whether carbon emissions from northern peatlands triggered by climate change will increase the chance and intensity of temperature overshoot. We found that, although northern peatlands continue to accumulate carbon, they represent positive feedback under climate change through their high CH4 emissions. For a 1°C increase in peak temperature anomaly, emissions from peatlands further contribute to the peak temperature by 0.02 (0.01-0.02) °C. Considering northern peatlands would lead to a reduction in the carbon budget by about 40 (16-60) GtCO2, or 8.6% for 1.5°C, and a reduction of about 105 (45-166) GtCO2 reduction (or 4.2% relative decrease) for 2.5°C. Our findings highlight the importance of properly accounting for northern peatland emissions for estimating climate feedbacks, especially under overshoot scenarios.
Development of a new low-cost multispectral radiometer for land and marine applications
Authors: Madonia Alice , Suman Swati , Piermattei Viviana , Marcelli Marco , Valentini Riccardo
Published: March 2024

To face the need of mitigation and adaptation measures in order to reduce climate change impacts and improve the robustness of climate projections it is necessary to implement long-term and low-cost observing systems.One of the main problem is the acquisition of in situ optical data, fundamental to understand the functioning of natural ecosystems since light is the primary source of energy for both terrestrial and marine life. In fact, light directly affects the photosynthetic processes and its availability represents a key factor for primary production.In this context, there is a lack of spectro-radiometric and PAR measures in the marine environment to retrieve key bio-optical variables for the validation of remote sensing observations, providing useful information on the effects of anthropogenic activities and climate change.Commercial high-performance spectrometers are characterized by high costs thus limiting the acquisition of a great amount of data for remote sensing and numerical models validation. In the last decades, a big effort was dedicated to the development of miniaturized and autonomous systems to reduce the costs of both land and marine observations while maintaining adequate performance and significant data quality.In this work we present the development of a new low-cost multichannel spectrometer designed and developed as a fast, accurate and effective device for spectral response monitoring.To optimise the selection of the optical components and to assess the performance of the developed system, a series of experimental tests were performed both in laboratory and in field. This work shows the results of the developed technology and its applications.
3D Velocity field of Romania derived from more than 20 years of continuous GPS observations
Authors: Muntean Alexandra , Ambrosius Boudewijn , Nastase Eduard Ilie , Munteanu Ioan
Published: March 2024

Abstract      The Earth's surface is continuously transformed, with deep and superficial processes contributing to the present-day morphology. Evaluating the contribution of each process and interaction between tectonics, climate, and human activities is difficult, especially in areas with relatively low crustal deformation.      With this study, we aim to better understand the tectonic and sub-surface geodynamic processes that result in (small) surface motions in Romania. We are particularly interested in the Eastern Carpathians Bending Zone (Vrancea region), where strong deep earthquakes occur. Furthermore, we are focused on the interaction between the Eurasian, and Aegean tectonic plates. For this purpose, we processed more than 20 years of cGPS data from various networks in Romania (more than 100 stations), using the GipsyX software. To put our results in a broader perspective, we also included similar results published in open-source online literature including countries around Romania. Combining all these solutions we generated a velocitiy horizontal and vertical velocity fields for this extended region. All solutions were converted to the Eurasian tectonic reference plate in the ITRF14 plate rotation model.      We find that in general, the horizontal velocity vectors in Romania have small values, ranging from 0.0 mm/yr in the north to 1.5 mm/yr in the south, and notably, the majority of stations indicate a subtle yet significant downward motion of 1.0 -2.0 mm/yr. In contrast, to our expectations, we did not find any significant horizontal and vertical motions in the Vrancea region. The horizontal motions exhibit a strong, generally southward, and gradually increasing trend, starting south of the South Carpathians. The trend is in the direction of the tectonic plates in southeast Europe. It means that the intraplate deformation zone extends to south Romania. The observed patterns contribute to our understanding of intraplate deformation and emphasize the need for continued regional research.Keywords: crustal deformations, GPS, geophysics, tectonics  AcknowledgmentsThis paper was carried out within Nucleu Program SOL4RISC, supported by MCI, project no PN23360101, and PNRR- DTEClimate Project nr. 760008/31.12.2023, Component Project Reactive, supported by Romania - National Recovery and Resilience Plan
3D imaging of Rayleigh wave mantle attenuation with uncertainty quantification
Authors: Ferreira Ana M.G. , Sturgeon William
Published: March 2024

We present global 2-D maps of frequency-dependent attenuation based on a huge dataset of ~10 million Rayleigh wave amplitude measurements. We incorporate fundamental mode and up to 4th overtone measurements over a period range of 35-200 s to ensure sensitivity in both the uppermost mantle and in the transition zone. In order to isolate intrinsic anelastic attenuation structure, we account for source, path and receiver effects on the amplitude data. Most prominently, we account for focusing/defocusing effects along the ray-path using complementary phase velocity maps. Following the removal of outliers based on strict data selection criteria, the resulting dataset is inverted using a least-squares approach along with a thorough exploration of model regularisation.Our maps show a strong correlation between attenuation and surface tectonics up to periods of T~100 s, with low attenuation beneath the continents and high attenuation beneath the oceans. Our maps also show a commonly observed age progression trend in ocean basins, with lower attenuation beneath older oceanic crust. In particular, our maps delineate all major global cratons, including some separation between the Congo and Kalahari cratons in Africa, as well as the reletively small North China craton between T~40-100 s. The East Pacific Rise, western North American and hotspots correlate with high attenuation up to T~100s, but then correspond to low attenuation regions at periods greater than T~180 s. As to be expected, uncertainties are higher in regions of poor data coverage (e.g., southern hemisphere and oceans).We then, for the first time, jointly invert frequency-dependent Q-curves for 1D profiles of shear-attenuation using the Monte-Carlo based Neighbourhood Algorithm. We discuss the implications of our resulting 3D model in terms of mantle temperature and composition anomalies.
Assessing the effect of conventional and conservation tillage methods on soil moisture under drought progression
Authors: Irkiso Adane , Chemura Abel , Kuhwald Michael , Thieken Annegret
Published: March 2024

Tillage is an agricultural practice that aims to create a favorable environment for crop production. Nonetheless, the intense field traffic by tillage, in the worst-case, is considered a detrimental anthropogenic practice to the soil. By impeding soil water movement, tillage might exacerbate the impact of droughts. To limit drought impacts, adapting tillage practices is one management option.In this study, we aimed to evaluate the effect of tillage practices on soil moisture. For this purpose, we deployed 28 point-based plant care soil moisture sensors at 20 and 40 cm soil depths, in a farm field in Lower Saxony, Germany on silt loam divided into three different sections based on tillage type with different tillage depths (moldboard – 30 cm, chisel plow – 25 cm and disk harrow – 10 cm) implemented consistently for more than twenty years. The effect of tillage types on soil moisture was analyzed for different crop development phases of sugar beet and drought severity levels in 2022. For the latter, the soil water deficit index was used, which is computed based on soil moisture content at field capacity and permanent wilting point. Additionally, we ran DSSAT model simulations to evaluate the potential of nature-based solutions, such as no tillage and mulching, on maximizing soil moisture conservation during drought period.Our result showed a temporal variability in soil moisture content between the three different mechanical tillage depending on the drought severity level. Moreover, our DSSAT simulation indicated that mulching tends to improve soil moisture content and to reduce runoff and soil evaporation.
Dune-based Nature-based Solutions in Ireland: unlocking their full potential to build coastal resilience 
Authors: Farrell Eugene , Lynch Kevin
Published: March 2024

Ireland has made a commitment under the newly developed Marine Strategy Framework Directive Programme of Measures to develop Nature-based Solutions to conserve and restore estuarine, coastal and marine habitats. Existing evidence show that a large number of coastal communities, environmental NGO’s, EU-funded research programmes and local government bodies are already engaged with the transition towards NbS to defend or conserve coastlines with varying degrees of success. This research first provides an overview of over fifty NbS projects in Ireland in different coastal habitats (dunes; machair; saltmarshes; seagrass meadows; oyster reefs; kelp forests) being led by different organizations with different motivations, services delivered, biodiversity value, beneficiaries, and resources. We then present multiple dune-based NbS case studies along urban and rural coastlines to illustrate how these projects are successfully building coastal resilience. It is obvious to NbS practitioners that many of these projects are not sustainable in the long-term and overly rely on the selfless work of volunteer groups who continuously face institutional (governance; legal responsibility; stakeholder forum; tourism) and technical barriers (climate adaptation; funding; environmental designation; lexicon of climate resilience and sustainability; erosion and flooding control; seasonal tourism) in their attempts to build resilience to climate change and anthropogenic pressures. To unlock the full potential of dune-based NbS, Ireland urgently requires (1) new government policies and planning structures to organize the planning, implementation and maintenance of NbS, including a coastal community engagement mechanism to coordinate working partnerships and funding between local government bodies, coastal communities, and landowners at every stage in the process; (2) appropriate and expert staffing resources (e.g., climate and biodiversity officers) within local government authorities and the National Parks and Wildlife Service, the state agency responsible for Ireland’s nature conservation; (3) a standardized NbS indicator framework to measure the ‘impact’ of NbS projects; and (4) a valid financial mechanism to facilitate significant future investment in NbS as ‘new assets’ and biodiversity credits (measurability, monitoring, verification, and certification of the NbS process). 
Assessing the potential of bacterial and archaeal membrane lipids (GDGTs) to reconstruct Late Pleistocene and Holocene climatic changes in the Canary Islands
Authors: Davtian Nina , Castilla-Beltrán Alvaro , Martín Ramos María del Pilar , Fernández-Palacios Enrique , Criado Constantino , Nogué Sandra , Villanueva Joan , Fernández-Palacios José María , de Nascimento Lea
Published: March 2024

Sedimentary records covering the Late Pleistocene show glacial-interglacial and millennial temperature changes accompanied with, for instance, rainfall and vegetation changes at the global and regional scales. However, such records are missing for the islands of Macaronesia.Here we generate three sedimentary records over the last 10,000 to 45,000 years from the islands of Tenerife, Gran Canaria, and La Gomera using glycerol dialkyl glycerol tetraethers (GDGTs). At the global scale, air temperature and soil pH influence GDGT distributions in soils, although these biomarkers also react to other environmental factors (e.g., land use, vegetation, and soil moisture and chemistry) and shifts in bacterial and archaeal communities. Accordingly, we examined several GDGT-based proxies, notably those using bacterial branched GDGTs (brGDGTs), to assess their applicability in the Canary Islands.Our preliminary results show drastic downcore and inter-site changes in GDGT distributions, with brGDGT-based air temperature ranges larger than 10 °C over the last 10,000 to 45,000 years when applying global calibrations at the three study sites. Air temperatures and soil pH inferred from brGDGTs decrease in Tenerife and La Gomera over the end of the African Humid Period, which suggests an effect of reduced rainfall on brGDGTs, possibly accompanied with a shift in bacterial communities. Air temperatures inferred from brGDGTs show a general increase over the last 27,000 years in Gran Canaria, whereas cyclization and isomerization indices of brGDGTs suggest typically opposite changes in soil pH, in disagreement with global-scale patterns from surficial soils. Our GDGT-based records also show a few drastic increases in archaeal GDGT abundances relative to the full GDGT pool after the Last Glacial Maximum, notably in Gran Canaria and La Gomera, partly related to the rainfall increase during the African Humid Period.Our preliminary application of GDGT-based proxies in the Canary Islands reveals complex environmental influences on soil bacterial and archaeal lipids, which may also be related with local climate and vegetation dynamics. Our preliminary study also motivates a follow-up GDGT study in surficial soils from the Canary Islands to establish, for instance, a brGDGT-temperature calibration suitable for this archipelago.
Impact of the Asian Monsoon Anticyclone on Extratropical Lower Stratospheric Water Vapor Distribution observed during the PHILEAS aircraft campaign
Authors: Rolf Christian , Hoor Peter , Ort Linda , Weyland Franziska , Zahn Andreas , Riese Martin
Published: March 2024

The Asian monsoon anticyclone (AMA) stands as a critical player in regional climatic dynamics, wielding profound influence on atmospheric circulation patterns. Despite its well-documented impact on surface weather systems, an intriguing and less-explored dimension of its influence lies in the extratropical lower stratosphere. Especially, water vapor, a climatically significant component, plays a pivotal role in shaping the Earth's radiative balance and, consequently, its climate. Water vapor in the lower stratosphere acts as a key driver of radiative processes, influencing temperature profiles and atmospheric energy distribution.
This study focus on recent measurements from the recent HALO research aircraft campaign PHILEAS in fall 2023, incorporating data on water vapor, methane, and ozone concentrations in the extratropical lower stratosphere. By combining the observational data with meteorological data from ECWMF, we aim to unravel the intricate interactions between the Asian monsoon anticyclone and the distribution of these key atmospheric constituents. The integration of water vapor, methane as AMA tracer, and ozone measurements as stratospheric tracer allows us to discern the specific contributions of the Asian monsoon anticyclone to the composition and dynamics of the extratropical lower stratosphere and the change of the water vapor distribution over the campaign time frame.
Know before you act. Effective risk education (should) starts from knowing gaps and preconceptions. A case study on sea level rise.
Authors: Solarino Stefano , Musacchio Gemma , De Lucia Maddalena , Eva Elena , Anzidei Marco
Published: March 2024

Nowadays everybody agrees that increasing preparedness for natural and not-natural hazards and fostering best practices is of paramount importance for a resilient society. Therefore, in the last years many scientific projects included a task, a work package - or were themselves - fully devoted to transferring the results of the studies carried on within the project to the society. This included intensive education activities to train people about a specific hazard.However, educative and dissemination packages are often too generic or too specific, especially in cases where the natural hazard is not well known by the public or affects a limited area or population. In these cases, it may be helpful to carry out preparatory research to finely tune the educational aims/objectives.We present the results of an online survey carried out in 2020–2021 to understand citizens’ level of knowledge about the phenomenon of sea level rise, including causes, effects and exacerbation, in order to finalize educational tools.Since the last century, global warming has triggered sea level rise at an unprecedented rate. In the worst-case climate scenario, sea level could rise by up to 1.1 m above the current level, causing coastal flooding and cascading effects, thus affecting around one billion people worldwide and potentially becoming one of the most important climate issues in the future.Our survey revealed that, although widespread and threatening, the phenomenon is not well known to citizens as it is often overshadowed by other effects of global warming. The results of our study were peculiar to prepare an educational campaign and set up initiatives for students and the public.
The impact of anthropogenic changes on socioeconomically marginalized population in urban areas: A case study of flood risk in Seoul, South Korea
Authors: Ro Bokjin , Park Hongbong
Published: March 2024

Climate change, one of the most remarked anthropogenic changes, has increased the intensity and frequency of heavy rainfall events. Heavy rainfall events pose challenges especially in urban areas, which have a higher rate of impervious surface, compared to non-urban areas. Seoul, the capital city of South Korea is not an exception for the cities that contend with flooding. During summer, the meteorological condition forming over the Korean peninsula brings rainfall constituting approximately 35-55% of the country’s annual precipitation. Seoul has undergone rapid development and urbanization, which also are the examples of anthropogenic changes, for the last five decades; the city’s current population is about 4.7 times larger than that of the early 1960s. This fast population increase created a distinctive housing type known as semi-basement housing, symbolizing socioeconomic marginalization. Despite ongoing efforts by the Seoul Metropolitan Government to mitigate flood risk citywide, most of the households living in the semi-basement housing, particularly in low-lying areas, remain highly susceptible to flooding whenever heavy rainfall events occur. This study focuses on Gwanak-gu, one of Seoul’s 25 districts and the district with the highest concentration of semi-basement housing. The study examines how anthropogenic changes in both physical (i.e., climate change) and social (i.e., urban development and urbanization) environment exacerbate the already marginalized people’s vulnerability floods. The results show that the same amount of heavy rainfall (e.g., 100mm per hour) pouring in the district significantly heightens the level of exposure for the semi-basement housing than the exposure level of housing that is not semi-basement. This implies that the climate change and urban development and urbanization (i.e., anthropogenic changes) make the vulnerable people even more vulnerable, even as the measures aim to alleviate overall flood risk across the city have been implemented. In other words, anthropogenic changes, even though the government’s risk mitigation efforts exist, tend to polarize the vulnerability and exposure to floods. Drawing from the results, the study emphasizes the need for more considerate measures to truly reduce the flood risk of the city. It concludes by suggesting potential strategies that could contribute to reducing flood vulnerability of the marginalized populations and lowering overall flood risk in the city.
“Evaluation of the near field effects trough numerical modeling: the case of Norcia (Italy)”
Authors: Caciolli Maria Chiara , Giallini Silvia , Pagliaroli Alessandro , Barchi Massimiliano Rinaldo , De Franco Roberto , Fiorentino Gabriele , Mancini Marco , Moscatelli Massimiliano
Published: March 2024

The near field condition in seismic events is characterized by its immediate proximity to the seismic source, and is widely proven that ground motion near a causative fault (Near field) can differ significantly from typical ground motion observed at greater distances (far field).Features of near-fault ground motion are high vertical accelerations and the occurrence of high-amplitude, long-duration (2–5s) pulses observed in velocity–time and displacement–time histories aligned with the fault's normal direction. These features and the other effects linked to this condition are critical factors in causing potential damage to structures as the seismic motion in the near-field can subject structures to seismic demands that differ from the design criteria, primarily in terms of intensity and the nature of ground motion.As the seismic hazard quantifies the ground motion expected at a given site, understanding and predicting near-field effects are vital for seismic hazard assessment, structural design, and risk mitigation in the areas where near-field conditions occur.This study aims to investigate the near-field effects in seismic events by employing two-dimension numerical simulations carried out with FLAC 2D Finite Difference Code, to reproduce the features observed during a real earthquake occurred.The selected area is the Norcia plain, one of the intermountain basins widely present in Central Italy—a context of significant interest due to its association with high seismic hazard and high exposure in urban agglomerations. Several active seismic stations have recorded the last important seismic sequence (Central Italy 2017-2018) in particular the third and largest event on 30th October (6.5 Mw), whose epicenter was located close to Norcia (4 km). The validity of near-field conditions for this event has already been established by previous studies.Other scientific studies have been carried out in this direction in similar geological contexts with other software and the advancing here proposed is performing simulations using a non-horizontal interface geometry to apply the seismic input, with both horizontal and vertical components. The simulations consider a geological and tectonic model with few variables changing to provide a comprehensive understanding of how results may be affected by the knowledge of the geological and geotechnical setting, gained from basic studies.This study could have important implications to suggest an updating of the seismic code and the general approach in the seismic design of structures located in the near field domain, for a careful and reliable assessment of seismic risk.
Ionospheric Scintillation Nowcasting and Forecasting for Civil Aviation
Authors: Yaya Philippe , Souissi Roiya , Cherrier Marie , Naouri Ali
Published: March 2024

The International Civil Aviation Organization (ICAO) has set up a space weather service for monitoring and raising alerts in case of moderate or severe potential impact on aviation, and covering three domains: GNSS, Radiation and HF Communications. This service is operational since November 2019 and is working in a bi-weekly rotation of four global centers: SWPC (US Space Weather Prediction Center), PECASUS (consortium of 9 European States), CRC (China-Russia Consortium) and ACFJ (Australia-Canada-France-Japan). CLS (Collecte Localisation Satellites), a member of ACFJ, is a subsidiary of the French Space Agency and responsible for delivering near real-time ionospheric scintillation maps. The input data is based on a worldwide network of GNSS receivers, composed of various regional and global networks. The work presented here summarizes the adopted algorithms and pre-processing tasks leading to generate the nowcast maps. The results of a validation work are shown (comparison of indices from geodetic receivers and scintillation monitors) as well as a focus on severe events and their effect on aviation. Finally, taking advantage of a 4-years long data base, the status of a forecasting scintillation model is presented, taking care of separating the EPBs (Equatorial Plasma Bubbles) and geomagnetic storms origins.