bluuebunny/crossref_metadata_2025 huggingface dataset:
Measuring cliff top and cliff face retreat rates of a coastal drumlin using Structure-from-Motion in Galway Bay, Ireland
Authors: Rink Gregor , Bromley Gordon , Farrell Eugene
Published: March 2024

Sea cliffs comprise approximately 80% of the world’s coasts. Rapidly retreating cliffs are a widespread problem that threatens property, transport infrastructure and public safety. Cliff retreat rates depend on highly localised characteristics of the cliff itself, as well as on the land behind the cliff and the intertidal and marine environments in front of it. In addition to these physical properties, retreat rates are also influenced by the methodology applied. Traditionally, estimates of coastal cliff top retreat have been based on historic map and arial photograph (century scale) analyses that provide long-term rates but fail to provide information in short-term processes driving coastal evolution. Newer datasets from satellite imagery and uncrewed aerial vehicles (UAV’s) are being coupled with new techniques like Structure-from-Motion (SfM) to dismantle cliff top and cliff face dynamics at shorter timescales (weeks to months). It is now accepted that estimates of cliff retreat rates can differ substantially when calculated from cliff top versus cliff face analyses, usually finding that cliff-top retreat rates are higher than cliff-face retreat rates.This study combines historical data (maps and aerial photographs 1842 – 2000) with contemporary UAV imagery (2019 – 2023) to analyse cliff top and cliff face dynamics of a 250 m wide coastal drumlin at Silverstrand in Galway Bay on the west coast of Ireland. The cliff top changes were analysed using the Digital Shoreline Analysis System (DSAS) in the ESRI ArcGIS Desktop platform. Cliff face change detection was done using a Multiscale Model to Model Cloud Comparison (M3C2) in CloudCompare. By using these different types of data and methods, we were able to calculate retreat rates of the cliff top and the cliff face independently. The average cliff top retreat rate between 1842 and 2023 (181 years) was estimated to be 0.14 +/- 0.02 m/year. The average cliff face retreat between 2019 and 2023 (4.45 years) was estimated to be 0.08 +/- 0.02 m/year. For both, cliff top and cliff face retreat rate, we found that the long-term retreat rates are lower than the short-term retreat rates and that the western part of the cliff experiences higher erosion than its eastern counterpart. This variability might reflect multiple erosional processes and differences in magnitude-frequencies of erosional events at the cliff top and cliff face, or even the application of various methods and datasets.Our results are consistent with other soft rock cliffs in Ireland and globally in similar settings. Nonetheless, more detailed observations using shorter timescales and monitoring intervals are warranted to identify and quantify the rates, patterns, timing and magnitude- frequency of cliff retreat phenomena.
Are we missing future extreme events by ignoring less persistent blocking?
Authors: Shelke Prasad , Jendersie Stefan , Golledge Nicholas
Published: March 2024

Extreme weather events are often linked to atmospheric blocking. While a comprehensive theory of blocking is yet to be developed, the onset mechanism of these systems poses a major challenge. As a result, the representation of blocking in climate models is inadequate and consistently underestimated. Although successive improvements in the blocking representation are evident in climate models, they still underestimate the blocking frequency in the Northern Hemisphere (NH).In this study, we observed an improvement in the representation of blocking in the Community Earth System Model Large Ensemble 2 (LENS2) during winter and a notable deficiency during summer. When compared with observations, the winter blocking bias (-4% to +2%) was found to be substantially reduced, while the summer blocking exhibited a significant bias (-12% to +12%) compared to previous studies. Under the SSP370 scenario, LENS2 suggests an overall decline in winter blocking (11%) and an increase in summer blocking (12%) by the year 2100 in the NH.The underlying reason for the underestimation of blocking in climate models is often associated with the mean jet state and stationary waves. However, the lack of an onset theory causes challenges in identifying blocking systems. There is also a missing explanation of why temporal persistence is considered specifically as 5 days. Thus, we define less persistent blocking (LPB) as a blocking regime that satisfies the flow reversal criterion and persists for less than 5 days. We found a significant presence of the frequency of LPB (~15% to 25% maximum) in the NH in both models and observations. It means that we were ignoring the presence of these blocking systems, which may have a role in driving extreme events and can potentially emerge as stronger and more persistent blocking systems in the future.Interestingly, the hotspot of LPB includes drought-prone regions such as the western coast of the United States and well-known blocking centers such as the Euro-Atlantic and Pacific regions. This leads us to propose a new potential avenue for studying the precursors of LPB dissipation, which will provide insights into the longstanding problem of the blocking onset mechanism.
Comparative analysis of Machine Learning models for predicting the trihalomethanes formation potential in a Drinking Water Treatment Plant in Spain
Authors: Pla-Castellana Mireia , Gutierrez Oriol , Raich-Montiu Jordi , Gernjak Wolfgang
Published: March 2024

Trihalomethanes (THMs), which may be harmful to human health if ingested or inhaled, are produced when organic matter reacts with chlorine. Hence, their formation during potabilization requires to be controlled to ensure safe drinking water.In this study, the predictive capacity of a Multiple Linear Regression (MLR) and an Artificial Neural Networks (ANN) models have been compared with real-time field-scale data of the THM formation potential (THM FP) from a Spanish Drinking Water Treatment Plant (DWTP). Spectral absorbance data obtained with Spectro::lyser® probes, installed in several treatment steps of the plant were the independent variables used to construct the models. Variable selection was based on the Stepwise Selection (SS) procedure.Following the fitting of the investigated models, ANN demonstrated precise goodness of fit (R2 = 0.92; RMSE = 0.77), clearly outperforming the MLR model (R2 = 0.35; RMSE = 1.65). Severe multicollinearity among wavelengths is responsible for the model's accuracy difference. Even though it was reduced by a prior study on the Variance Inflation Factor (VIF), it was still very high for some of the remaining wavelengths. As a result of this effect, large fictitious correlations were produced, which adversely impacted the MLR model's prediction performance (R2 = 0.30 in the validation set). While R2 reduced, indicating perhaps a slight overtraining of the ANN, the resulting R2 in the validation set (0.72) was still very highThis study proved that Machine Learning models such as Artificial Neural Networks based on spectral absorption data can enhance the ability of operators to respond to critical events, becoming a decisive component of the daily management of drinking water in DWTP when needed.
Variability and trends in the PV-gradient dynamical tropopause
Authors: Turhal Anna Katharina , Plöger Felix , Clemens Jan , Birner Thomas , Weyland Franziska , Konopka Paul , Hoor Peter
Published: March 2024

The dynamical tropopause as a transport barrier between the tropical upper troposphere and extratropical lowermost stratosphere is characterized by steep gradients in potential vorticity (PV) along an isentropic surface. Hence, the latitudinal separation between the dynamical tropopause in the Northern and Southern hemispheres can be used as a metric of upper tropospheric width for assessing climate change impacts. Here, we calculate the PV gradient-based dynamical tropopause from different meteorological reanalyses (ERA5, ERA-Interim, JRA-55, MERRA-2) and investigate its climatology, variability and long-term trends. Our results show a large seasonal cycle in the dynamical tropopause, with larger PV values and a poleward movement in summer. The climatological tropopause PV values are substantially different between different reanalyses, but the tropopause latitude is similar. Significant inter-annual variability in the dynamical tropopause latitude is related to El Niño Southern Oscillation (ENSO), is much weaker for the Quasi-Biennial Oscillation (QBO), and is robustly represented in reanalyses. In particular, El Niño causes equatorward shifts of the dynamical tropopause, hence a decrease of upper tropospheric width. Long-term trends in the dynamical tropopause exhibit a distinct vertical structure with poleward shifts below 340 K potential temperature, equatorward shifts between 340 K to 370 K and poleward shifts between 370 K to 380 K, implying an expansion of tropospheric width at lower levels, narrowing at upper levels and expansion near the tropical tropopause. Therefore, the dynamical tropopause as a metric for tropospheric width at a given level appears consistent with a widening of the tropics found from other metrics at lower levels, and furthermore shows a concurrent narrowing of the tropical upper troposphere. 
Future satellite gravity field missions – Impact of a direct time-variable parametrization
Authors: Zingerle Philipp , Pail Roland , Gruber Thomas , Daras Ilias
Published: March 2024

The limited achievable temporal resolution poses one of the main limitations of current satellite gravity field missions such as GRACE and GRACE-FO and is, eventually, responsible for temporal aliasing. Increasing the temporal resolution is thus one of the most important tasks for future satellite gravity field missions. This, however, can only be achieved by means of larger satellite constellations since the temporal resolution can basically be defined as the time needed to achieve a global observation coverage. This needed (retrieval) time scales linearly with the number of satellites: e.g., a two-pair mission such as the upcoming joint ESA/NASA MAGIC mission can easily achieve global coverage with sufficient spatial resolution within less than a week. For a hypothetical 6-pair mission, even an independent daily retrieval is feasible. Future missions will hence allow to sample the gravity field in much shorter intervals. However, up until now, the parametrization of the gravity field within these intervals usually only accounts for a static behavior, resembling a step function in the time domain. Obviously, such a behavior is unnatural and does not follow the actual progression of the gravity field. So, even if sufficient temporal resolution would be available, temporal aliasing will not be fully mitigated due to this mis-parametrization. In this contribution we will thus investigate the impact of a direct time-variable parametrization through continuous spline-functions. On the example of a fictive 6-pair mission, we show how such a spline parametrization with daily support points can be applied: firstly, we prove that the spline parametrization allows numerically stable and correct solution based on a closed loop scenario without residual (sub-daily) temporal aliasing. Secondly, based on a more realistic scenario with sub-daily temporal gravity signal, we also highlight the (theoretical) limitations of a 6-pair mission due to the still very dominant temporal aliasing (from sub-daily signal sources). This work is supported by the ESA QSG4EMT study in collaboration with Politecnico di Milano, Delft University of Technology, HafenCity University Hamburg, University of Bonn and University of Trieste.
Poroelastic heterogeneity in the presence of a fresh fault: experimental insights and numerical modelling
Authors: Liu Dong , Brantut Nicolas
Published: March 2024

During natural and induced seismic activities, pore fluid pressure within fault zones and their surrounding rock may respond differently to stress variations, introducing additional complexities to seismic hazard assessment. While theoretical investigations have recognized the influence of such poroelastic heterogeneity on fault instability, incorporating phenomena like slip-induced dilation or compaction, the chosen poroelastic properties in these studies lack robust constraints from experimental measurements. Addressing this gap, our study focuses on quantifying the heterogeneity of poroelastic properties in the presence of a fresh fault, aiming to elucidate the coupling between poroelasticy and fault dilatancy during fault slip.In our experimental investigation, we examined the evolving dynamics of pore pressure both on- and off-fault in initially intact Westerly granite samples. Applying confining stress of 100 MPa and a pore pressure of 60 MPa at two sample ends to replicate crustal settings, we induced a sliding fault plane through loading to failure under a constant strain rate. In the faulted samples, we measured the pore pressure response under sudden step loading in the direction of the maximum compression σ1. Each loading step of around 5 MPa was imposed incrementally increasing the differential stress from 5 MPa to approximately 80 MPa (frictional resistance) after achieving pore pressure equilibrium. Detailed measurements, including displacement, bulk deformation, differential stress, local pore pressure and acoustic emissions were recorded throughout these tests. A spring-slider model coupled with 1-D fluid diffusion was used to try to simulate experimental observations.Our results indicate that both the shear zone and the bulk exhibit a diminishing Δp/Δσ1 with increasing differential stress. Measurements within the fault zone consistently yield positive values, surpassing those off the fault, with the discrepancy more pronounced at lower stress levels. In regions farther away from the shear zone, the off-fault response Δp/Δσ1 presents a smaller value compared to locations proximal to the fault zone and may even exhibit slight negativity. During fault slip, on-fault measurements exhibit an instantaneous increase upon step loading followed by a gradual decrease, as a result of the interplay between poroelasticity and fault dilatancy. These observations were effectively reproduced by the numerical model integrating the poroelastic measurements and rate-and-state fault friction with slip-dependent dilatancy. The implications of this investigation extend to an enriched understanding of the heterogeneity in poroelastic responses between fault zones and host rocks, serving as valuable benchmarks for informing future numerical simulations, particularly in the context of naturally formed fresh faults. 
Ground Deformation Prior to Phreatic Eruptions at Rincón de la Vieja Volcano, Costa Rica Detected Using GNSS
Authors: Mick Emily , Muller Cyril , Stix John
Published: March 2024

Studies of deformation in volcanic settings are typically focused on active magmatic systems where inflation due to the injection of magma is an important indicator of potential eruptive activity. Phreatic eruptions are the result of the sudden flashing of trapped water to steam without the eruption of magma, and the resulting deformation is at a much smaller scale that is more difficult to detect. Rincon de la Vieja volcano is highly active system in northern Costa Rica that experiences frequent, predominantly phreatic and phreatomagmatic, eruptive activity. Multiple GNSS stations are set up and maintained by OVSICORI as part of their nationwide network including stations located 1 km south-west (summit station) and 5 km northwest (flank station) of the active vent. The summit station shows repeated movement towards the vent (northeast) 1-2 months prior to significant eruptions (infrasound magnitude > 4.5) on January 30th, 2020, April 15th, 2020, May 25th, 2020 and January 6th, 2022. Using a 30-day moving average, the north-south component appears to be the most reactive with repeated deformation of approximately 5 mm compared to ~2 mm for the east-west component. The vertical component does not show a similar signal prior to single events, however it does show significant uplift (up to 20 mm) during periods of high eruptive activity. This signal is most prominent in 2020 and 2022 when Rincon experienced hundreds of eruptive events per year resulting in a saw-tooth pattern of deformation. Similar signals are not visible on the flank station, potentially indicative of a shallow pressure source close to the vent itself and consistent with pressurization within the shallow hydrothermal system. To date, a phreatic eruption has not been successfully forecast owing to a lack of reliable precursory signals. Improved eruption forecasting likely requires a combination of measurements to document changes in gas flux, seismic signals, thermal signatures, and deformation.
Observed structure of an internal tide beam over the Mid-Atlantic Ridge
Authors: Vic Clément , Ferron Bruno
Published: March 2024

Internal tides are key players in ocean dynamics above mid-ocean ridges. The generation and propagation of internal tides over the Mid-Atlantic Ridge (MAR) have been studied through theoretical and numerical models, as well as through moored, that is, one-dimensional, observations. Yet, observations remain sparse and often restricted to the vertical direction. Here we report on the first two-dimensional in situ observation of an internal tide beam sampled by a shipboard acoustic Doppler current profiler through a vertical section over the MAR. The beam is generated by the interaction of the barotropic tidal current with a supercritical abyssal hill that sits in the rift valley of the MAR. A vertical mode decomposition is carried out to characterize the spatio-temporal variability of the beam. Although the modal content of the velocity field is dominated by modes 1 to 3, higher modes display localized and not persistent bursts of energy. The use of an analytical theory for linear internal waves allows us to rationalize the observed velocity field and interpret it as the superposition of modal waves generated on the hill and propagating in the same direction. The observed beam is qualitatively reconstructed as the superposition of waves of modes 2 to 6. The velocity field was sampled seven times across the same section and displayed qualitatively different patterns, unveiling the complexity of the dynamics above the MAR. A ray tracing of modal waves shows that the refraction by mesoscale currents could explain the observed variability of the tidal beam.
Two years of aerosol and cloud observations from the Antarctic Peninsula.
Authors: Lachlan-Cope Tom , van den Heuvel floortje , Flynn Michael , Dyson Joanna , Smith Daniel
Published: March 2024

Clouds over the Southern Ocean and Antarctica are poorly represented within climate models. It is thought that our poor understanding of aerosol-cloud interaction at these latitudes could play a major role in biasing models towards consistently underpredicting cloud formation in these regions. Unfortunately, there are few studies of aerosols and their impact on clouds at high southern latitudes and those that do exist concentrate on the summer period. Here we present two years of observations from Rothera Station on the Antarctic Peninsula. The East Beach Hut clean air facility at Rothera Station has a comprehensive set of online aerosol instruments measuring size, composition, and the capacity to act as a Cloud Condensation Nuclei (CCN) in addition to offline filter samplers from which the concentration of Ice Nucleating Particle (INP) can be derived. Measurements of the aerosol precursor gas, dimethly sulphide are also available in addition to a micropulse LiDAR to give information on cloud properties. The object of these measurements is to identify the composition and source of the cloud nuclei active at high latitudes so they can be correctly incorporated within climate models through new or revised parameterisations. Here we report on the first two years of measurements and identify the correlation between chemical composition, biological activity and cloud nuclei activation.. We will present a comparison of aerosol and cloud nuclei during the Antarctic Summer and Winter of 2021-2023, offering an initial assessment of the different sources of CCN and INP observed during these periods.
ERODEM: Exploring Carbonate Rock Recession through Data Fusion of Extensive Experimental Data via Machine Learning
Authors: Mazzoli Claudio , Coletti Chiara , Germinario Luigi , Maritan Lara , Pozzobon Riccardo , Preto Nereo , Kraniotis Dimitrios
Published: March 2024

Pollution and climate change raise increasing concerns about the vulnerability of cultural heritage. In carbonate rocks, the primary concern is surface recession, which severely impacts the readability of details, preventing us from transmitting our legacy to future generations. Recession equations available in the literature are highly inadequate due to the complex relationship between climate conditions, hygrothermal (HT) behaviour, and stone textures. This is related to the limited set of parameters used by different authors and to the basic statistical approach used in their fitting processes.Through this research, we aim to develop a robust and reliable model to predict stone recession, employing Machine Learning algorithms supported by Multivariate Statistical Analysis. We will examine a large database of surface recession measurements obtained from different types of carbonate rocks, which differ in their textural features (e.g. grain size, porosity) and HT behaviour (e.g. water vapour permeability), and of the relative micro-climate conditions under which they have been exposed during outdoor experiments. Additional recession data will be derived from laboratory experiments using an autoclave, allowing precise regulation of pH and temperature of water in contact with stone samples. Validation of the predictive model will involve comparing the recession predictions based on the time series of climate data and material characteristics with the observed recession obtained through the meticulous comparison of historical plaster replicas with the original monuments. This comprehensive analysis aims to ensure the model accuracy in capturing the real-world complexities of carbonate rock surface recession under varying environmental conditions. Acknowledgement:ERODEM project was funded by the Department of Geosciences through the “Progetto Premiale” call. This initiative is part of the larger project "Le Geoscienze per lo Sviluppo Sostenibile," funded by the Italian Ministry of University and Research (MUR) within the frame of the “Progetti di Eccellenza 2023-2027”.
Monitoring The Development Of Land Heatwaves Using Spatiotemporal Models
Authors: Mazumder Swarnalee , Hahn Sebastian , Wagner Wolfgang
Published: March 2024

This study introduces an approach for land heatwave forecasting, using spatiotemporal machine learning models trained with ERA5 reanalysis data. We focused on key environmental variables like soil moisture, vegetation, and meteorological factors for modelling. The study utilized linear regression as a base model, augmented by more complex algorithms such as Random Forest (RF), XGBoost, and Graph Neural Networks (GNN). We defined heatwaves using temperature data from 1970-2000, and the training phase involved data from 2000 to 2020, focusing on predictive accuracy for 2021-2023. This methodology enabled a detailed exploration of heatwave trends and dynamics over an extended period. Finally, we used explainable AI methods to further deepen our understanding of the complex interplay between environmental variables and heatwave occurrences.
Constraining CMIP6 model ensemble spread to reduce uncertainty in the representation of the Atlantic water layer temperature in the Arctic Ocean
Authors: Devilliers Marion , Olsen Steffen M. , Yang Shuting , Langehaug Helene R. , Tian Tian , Guo Chuncheng , Mahmood Rashed
Published: March 2024

We aim at reducing the uncertainties in the climate predictions of the Arctic region which is going under rapid changes with global repercussions. We analyse the spread in the Atlantic water core temperature across multi member CMIP6 historical simulations, focusing on different regions of the Arctic Ocean. While the redistribution of heat plays a critical role in the dynamics of the Arctic Ocean basins, it is usually not well represented in climate models, leading to divergent projections of future changes in the Arctic. To address this limitation, we compare CMIP6 model outputs with available reanalysis and observational products, in order to identify the biases within the model simulations and develop new metrics to constrain the model ensemble spread. Such metrics can be used to select the multi model ensemble members and construct a subsample with improved representation of the core temperature evolution over the historical period resulting in a reduced uncertainty in near-term future projections of the Arctic climate.
Sensitivity of Microphysical Properties of Mixed-Phase Clouds on Model Resolution and Microphysics Scheme in ICON
Authors: Hoose Corinna , Waman Deepak , Keshtgar Behrooz , Barthlott Christian , Wallentin Gabriella
Published: March 2024

Microphysical processes in the mixed-phase clouds play an important role in modulating the earth’s weather and climate. However, uncertainties in both observational data and model parameterization of microphysical properties (e.g., number concentrations of ice particles) constrains our ability to accurately simulate mixed-phase clouds and their impact with weather and climate models. Model configuration, such as one- or two-moment microphysical schemes, horizontal and vertical resolution of the model can affect the representation of cloud and precipitation processes and cloud radiative effects. For simplicity, many numerical models use 1-moment microphysical scheme to represent clouds. However, this scheme may not represent microphysical and precipitation processes accurately as it only predicts the mass or number mixing ratios of hydrometeors. To address this issue, the present study uses the Icosahedral Non-hydrostatic (ICON) model to assess the sensitivity of model configuration by comparing the predicted microphysical properties with the observations. In ICON, the one-moment microphysical scheme represents mass fractions of five cloud as well as precipitation particles such as: cloud water and ice, snow, graupel, and rain. Furthermore, the two-moment microphysical scheme in predicts both mass and number mixing ratios of hail and the five prognostic variables mentioned above. For the above discussed purpose, a case of observed mixed-phase clouds will be simulated with ICON. The profiles of the simulated cloud microphysical properties will be compared with the coincident aircraft and ground-based observations. Furthermore, various simulations will be performed by varying the vertical as well as horizontal resolution to analyse the changes in model predicted microphysical properties.
Spatiotemporal evolution of subaerial ice cliff heights at marine-terminating outlet glaciers in Northwestern Greenland
Authors: Carr Emma , Carr Rachel , Stokes Chris , Hill Emily , Gudmundsson Hilmar , Ross Neil
Published: March 2024

Many tidewater glaciers in Greenland terminate in near-vertical ice cliffs from which icebergs calve. Marine Ice Cliff Instability (MICI) is the hypothesis that above a subaerial ice cliff height limit, the tensile or shear stresses at the glacier terminus surpass the ice yield strength, causing catastrophic cliff failure and self-sustaining ice frontal retreat as sequentially taller subaerial cliffs are exposed. Previous modelling studies have proposed this threshold subaerial cliff height is at least 100 m, with estimated thresholds including 100 m and 110 m for damaged ice, and up to 540 m when ice is treated as undamaged. However, modern-day observations to test MICI are limited because few marine-terminating outlet glaciers without a buttressing ice shelf are known to terminate in subaerial ice cliffs greater than 100 m high. Here, we expand the observations of subaerial ice cliff heights at ten marine-terminating outlet glaciers in northwest Greenland using 2 m spatial resolution Arctic DEM strips. Our results identify three marine-terminating outlet glaciers that currently terminate in exposed subaerial ice cliffs approaching or exceeding the stability thresholds estimated for MICI. During at least two years between 2016 and 2021, subaerial ice cliffs at Nuussuup Sermia (NuS), Nunnatakassaap Sermia (NkS) and Sermeq North (SqN) exceeded heights of 100 m and 110 m. Despite being above these postulated thresholds thought conducive for cliff failure, SqN underwent relatively limited net retreat (0.25 km), and NuS and NkS exhibited distinct seasonal cycles of terminus advance (up to 0.92 km) from March to June/July each year prior to the disintegration and removal of proglacial ice mélange. Consequently, none of the glaciers identified as potentially susceptible to MICI underwent rapid, unforced retreat. We hypothesise that MICI processes were mitigated by dynamic thinning lowering the ice surface elevation immediately up-glacier of the ice cliff so that progressively taller subaerial cliffs were not exposed after retreat. Further research is required to monitor and model the evolution of subaerial ice cliffs to better understand the potential for unstable retreat in West Antarctica due to MICI.
Experimental Analysis and Creep-Fatigue Damage Modeling of Sandstone Deformation related to Energy Storage Systems
Authors: Tian Deyan , Song Zhengyang , Khaledi Kavan , Yang Zhen , Amann Florian
Published: March 2024

The porous sandstone formations offer large capacities for the geological storage of clean energy sources like hydrogen and compressed air. This paper aims to investigate the deformation mechanisms in sandstone under the varying loading conditions. Employing a combined experimental and numerical approach, we investigate the mechanical behavior of sandstone under cyclic loading conditions. The results obtained in this study indicate three distinct deformation regimes in sandstone specimens developed under multi-level, multi-frequency cyclic loads, i.e.,1) instantaneous elastic deformation, 2) transient and steady-state strain due to creep, and 3) rapid deformation leading to fatigue failure, mainly driven by micro-crack development. In response to these deformation mechanisms, a viscoelastic-damage model is proposed. This model is based on the standard Burger's viscoelasticity combined with an energy-driven damage model to represent the creep-fatigue behavior in sandstone. The modeling results were verified by comparing the predictions with the experimental data. The experimental and numerical results presented an essential insight for designing and managing geological storage systems in sandstone formations.
Variations of the authigenic 10Be/9Be-ratio in marine sediments during the Laschamps event and their use for dating of marine sediments
Authors: Loftfield Julia , Frederichs Thomas , Lachner Johannes , Lembke-Jene Lester , Liu Jiabo , Nowaczyk Norbert , Rugel Georg , Stübner Konstanze , Adolphi Florian
Published: March 2024

The atmospheric production rate changes of cosmogenic 10Be are caused by variations of the Earth’s and Sun’s magnetic fields and are recorded worldwide in different climate archives (e.g. ice cores, marine/lacustrine sediments, speleothems). This makes 10Be a useful tool to synchronize them, thereby overcoming the limitations in precision and accuracy of their individual age models.Here we present new 10Be/9Be data from a suite of marine sediment cores from the Scotia Sea, Drake Passage and South Pacific covering the Laschamps geomagnetic dipole minimum (~ 41 kaBP). Due to the reduction of the Earth’s magnetic shielding at this time, the 10Be-production rates roughly doubled, providing an ideal time marker for synchronization. We analyzed the cosmogenic 10Be and stable 9Be in the authigenic fraction of the sediments, which represents the 10Be/9Be signature of the surrounding water. Analyzing the 10Be/9Be ratio reduces the effect of variable particle scavenging rates on 10Be delivery to the sea floor. We compare our data to existing 10Be records from other marine sediment cores and ice cores, and to paleomagnetic field reconstructions. We discuss the potential and limitations of using 10Be/9Be ratios for dating marine sediments, and test whether using authigenic 10Be/9Be for synchronization is consistent with the traditional approach of matching climate records to reference sites.
ESA’s Earth Explorer Satellites – Advancing Measurement Capabilities in the Geoscience through the FutureEO Programme.
Authors: Scipal Klaus
Published: March 2024

Measurements and observations are essential to the development and advancement of understanding in the geosciences. Measurements are also critical to the detection and quantification of long term change and short term hazards, at a time when non-stationarity in Earth systems is increasing and extreme events are occurring daily. For many regions and domains however, observational networks are lacking, while the need for information is increasing due to growing human populations, intensifying geopolitical pressures and Earth’s rapidly changing climate.Through FutureEO, a series of world-class research satellite missions, the Earth Explorers, are realised. Since the successful launch of the first Earth Explorer in 2009, these missions, which are proposed by the scientific community, continue to demonstrate how breakthrough technology can deliver an astounding range of scientific findings about our planet. They lead to the scientific excellence that is critical to addressing the challenges society faces today and is expected to face in the decades to come – from understanding different aspects in the climate system such as atmospheric dynamics and ice melt, to societal issues such as food security and freshwater resources. Importantly, Earth Explorers also provide sound heritage for developing operational missions. For instance, some of the highly successful current suite of Copernicus Sentinel missions and the future Copernicus Sentinel Expansion missions would simply not be possible without the technology and application opportunities demonstrated by the Earth Explorers.This talk will present the FutureEO programme and its opportunities to advance our measurement capabilities in the geoscience. It will present the family of Earth Explorer satellites and future planned missions, highlighting their scientific goals and objectives. Based on lessons learned it will also discuss the challenges of launching first of its kind measurement systems and related science activities.
How the Hunga Tonga - Hunga Ha’apai water vapor cloud impacts its transport through the stratosphere: Dynamical and radiative effects
Authors: Niemeier Ulrike , Wallis Sandra , Timmreck Claudia , van Pham Trang , von Savigny Christian
Published: March 2024

The eruption of the Hunga Tonga - Hunga Ha'apai (HTHH) volcano on January 15, 2022 changed the water vapor content of the stratosphere. The eruption injected about 150 Tg of water vapor (H2O), roughly 10% of the background stratospheric H2O content, to altitudes above 50 km. Observations with the Aura Microwave Limb Sounder (MLS) detected the transport and distribution of the H2O cloud after the eruption. This provided a great opportunity to compare the simulated transport of the H2O cloud in the ICON-Seamless model with the MLS observation to see the performance of the stratospheric dynamics in this newly developed model. ICON-Seamless simulations were performed with NWP physics in a low horizontal resolution of about 160 km. A new vertical grid with 130 levels and a maximum grid size of 500 m in the stratosphere allowed the simulation of an internally generated QBO. The simulated spatial evolution of the H2O cloud is very close to the MLS observations. In both, model and observation, the vertical transport of the H2O cloud had three phases: an initial subsidence phase, a stable phase, and a rising phase. Radiative cooling of H2O clearly affects the transport of the H2O cloud, as demonstrated with passive tracers. It is the main driver within the subsidence phase. The radiative cooling also counteracts the large-scale rising motion in the tropics, leading to the stable phase, and modulates the large-scale transport of the H2O cloud for about nine months. This holds for different QBO phases, where the H2O cloud differs mainly in its vertical extent.
Future Predictions of Ecosystem Changes in California’s Sierra Nevada over the coming century using Remote-Sensing Constrained Terrestrial Biosphere Model Simulations
Authors: Chang Liling , Liu Shaoqing , Antonarakis Alexander , Longo Marcos , Tang Hao , Armston John , Moorcroft Paul
Published: March 2024

Reliable predictions of ecosystem dynamics and carbon stocks depend on accurate initialization of ecosystem states in process-based model simulations. Unlike traditional potential vegetation simulations which assume that ecosystems equilibrate with long-term climate, observation-initialized simulations integrate the impacts of previous history of disturbance events and human activities on ecosystem structure and composition. However, observation-constrained initialization is challenging at regional scales due to limited availability of spatially-comprehensive measurement data. In this study, we assimilate remote-sensing estimates of canopy structure from Global Ecosystem Dynamics Investigation (GEDI) and canopy composition from AVIRIS imaging spectrometry into Ecosystem Demography version 2 (ED2), a cohort-based Terrestrial Biosphere Model. We drive model simulations with future climate scenarios and rising atmospheric CO2 concentrations to predict ecosystem responses to environmental changes over an elevational transect region in California’s Sierra Nevada by the end of the century. Our simulations suggest that predictions are significantly impacted by ecosystem initial condition at the multi-decadal (50+ year) scale. The impacts are stronger in dense-canopy forests at mid-to-high elevations than woody savannahs at low elevations. Under a hotter and drier future climate with CO2 enrichment, ecosystems across the elevational transect are predicted to act as a net carbon sink but with marked changes in composition. Aboveground biomass (AGB) is predicted to increase at low elevations due to increasing abundance in both deciduous and coniferous trees. However, at mid-to-high elevations, AGB increases are caused by increasing abundance of coniferous trees but large declines in the abundance of deciduous trees. Our research demonstrates how large-scale remote-sensing data can be assimilated into process-based model simulations to improve future predictions of ecosystem dynamics.  
Future shifts in timing of regional extreme precipitation
Authors: Zhu Donghe , Pieper Patrick , Pfahl Stephan , Fischer Erich , Knutti Reto
Published: March 2024

Despite the high confidence in the overall intensification of the hydrological cycle in response to global warming, future changes in the spatiotemporal distribution of extreme precipitation remain uncertain. We here explore how climate change affects the seasonality and timing of extreme precipitation, which potentially alters its impact on society, economy and ecosystems substantially. Extreme precipitation events are defined as an exceedance of the all-day 98th percentile of daily precipitation.Most of the CMIP6 models capture the historical timing of extreme precipitation compared to the REGEN observational data. With climate change, we find distinct regional shifts in extreme precipitation across models. The most pronounced signal is a distinct shift of extreme precipitation from summer into the shoulder seasons, spring and autumn, or even into winter at latitudes between about 45°N and 75°N in Eurasia and northeast America.  These regions, which are climatologically characterized by extreme precipitation predominantly occurring during the summer, are projected to experience a strongly reduced fraction of extreme precipitation in summer during the second half of the 21st century.Preliminary synoptic analysis in individual models indicates a combined effect of limited moisture supply and weaker updrafts during the core summer extreme precipitation events. Further analysis is required to disentangle the relative role of thermodynamic and dynamic contribution to impact-relevant changes in seasonality of extreme precipitation.
Analysing the multifractality and cross correlations of river stage records using detrended fluctuation principles
Authors: Santhoshkhan Sumayah , Madhu Athira , Bahuleyan Muraleekrishnan , Rajesh Susan Mariam
Published: March 2024

This study presents the application of Multifractal detrended fluctuation analysis (MFDFA) for analyzing the multifractal properties of river stage time series of Indian rivers. Initially, the MFDFA method was applied to detect long-range correlations and multifractal behaviour of river stage time series of 81 locations from 11 basins of Peninsular India. The study found that all the Hurst exponent (H) values are found to be more than 0.5 indicating the long-range power law correlations in the stage data of Indian rivers. The different datasets indicated strong multifractal degree and a strong association between H and Holder exponent supported by a strong correlation over 0.98. Most of the multifractal spectra (93 %) indicated a positive asymmetry showing the frequent low fluctuations and localized high fluctuations. Basin wise analysis showed the strongest long-term persistence (LTP) and highest degree of multifractality for the datasets of Cauvery basin. In order to get an insight on the multifractality, MFDFA was applied to the daily data of corresponding period as that of stage observations. The analysis indicated that unlike the case of stage data 68 % of the data showed LTP while rest of the data displayed STP in the analysis. The multifractality of stage series is more than that of stream flow series at all river basins in India. Multifractal cross correlation analysis performed between daily river stage data and discharge data of same period indicated a strong correlation (>0.8) in majority of cases for different scales, despite the absence of a definite pattern in the correlation behavior for the data of different stations. This analysis is proven to be a very essential and useful prerequisite for developing stage-discharge relationships in a multifractal perspective, which may eventually help in proper flood management of Indian basins' changing climate scenario.Keywords: Persistence, multifractality, Stage, Streamflow, Correlation, Scale
ONERA accelerometers for future gravity mission
Authors: Dalin Marine , Christophe Bruno , Lebat Vincent , Boulanger Damien , Liorzou Francoise , Rodrigues Manuel , Zahzam Nassim , Bidel Yannick , Bresson Alexandre
Published: March 2024

The 2017-2027 Decadal Survey for Earth Science and Applications from Space has identified the Targeted Mass Change Observable as one of 5 Designated Mission. In Europe, ESA has confirmed at Ministerial Counsel of November 2022 to continue the development on the Next Generation Gravity Mission with a Phase B.These missions will continue the observation provided by GRACE and GRACE-FO. In these missions and the future concepts, the accelerometer provides either the gravity signal in a gradiometer configuration (GOCE type mission), or the non-gravitational acceleration to be suppressed to the ranging measurement between two satellites (GRACE-type mission).ONERA has procured the accelerometer for all the previous gravity missions (GRACE, GOCE, GRACE-FO) and works to improve the scientific return of the instruments for the future missions.In a frame of a contract with ESA, ONERA is developing its new accelerometer MicroSTAR, a high accuracy accelerometer with 3 sensitive linear acceleration measurements as well as 3 angular acceleration measurements for the attitude control or reconstruction.In parallel, a miniaturized version of MicroSTAR with low accuracy, CubeSTAR accelerometer, is developed with internal funding. CubeSTAR is adapted for constellation or nanosat.Another way is to improve the low-frequency noise of the accelerometer, by hybridization of electrostatic accelerometer with cold atom interferometer.The presentation will detail these developments.
Successful Deployment of a 21km SMART Cable with Force-Feedback Seismometer and Accelerometers in the Mediterranean Sea
Authors: Restelli Federica , O'Neill John , Nicholson Bruce , Watkiss Neil , Marinaro Giuditta , Simeone Francesco , Embriaco Davide , Price Ella , Foster Connor , Clark Aaron
Published: March 2024

Autonomous Ocean Bottom Seismometer (OBS) deployments have often involved a degree of “drop-and-hope” due to the inherent lack of seismic data communication during installation as well as waiting extended periods before data collection. Cabled solutions provide real-time data during and immediately after deployment, sometimes with opportunity to adjust the instrument before it is left to operate remotely. However, cabled solutions are inherently financially and logistically challenging both in terms of seismic hardware and arguably more significantly, deployment hardware (ships, ROVs, cables etc.). The geographical reach of these experiments is also often limited to within a few hundred kilometres of the coast. These constraints often mean cabled OBS are beyond the scope of most scientific bodies.Güralp Systems, in collaboration with INGV, has successfully manufactured and demonstrated a method of reducing financial and logistical constraints and extending geographical range by utilising force-feedback seismic instrumentation in cabled OBS systems. The recent successful deployment of the InSEA Wet Demo SMART (Science Monitoring And Reliable Telecommunications) cable displays a world first in how science can partner with industry to achieve this.SMART cables are primarily telecommunication cables that secondarily serve as hosts for scientific monitoring equipment. Commercial viability for these systems relies on the cable being laid as if the science element did not exist, thereby minimising additional deployment costs and reducing barriers to cooperation with cable laying companies. GSL and INGV deployed 3 seismometer-accelerometer pairs housed inline repeaters along the 21km cable length using standard cable-laying techniques to show proof of concept.This pioneering installation using telecommunication cables marks a significant step towards drastically improving local knowledge of inaccessible oceanic regions as well as global azimuthal coverage for teleseismic events, all in real time.