bluuebunny/crossref_metadata_2025 huggingface dataset:
MethaneCAMP project – overview of results
Authors: Tamminen Johanna ,   MethaneCAMP project team
Published: March 2024

The ESA funded MethaneCAMP project has focused on assessing, improving, and analysing satellite observations of methane (CH4) in the Arctic in support of the collaborative ESA-NASA Arctic Methane and Permafrost Challenge (AMPAC) initiative. Traditionally, the high latitude conditions have received minor attention when the satellite retrievals for methane have been optimised for global purposes as there has been known challenges caused by high solar zenith angles, low reflectivity over snow and ice, frequent cloudiness, varying polar vortex conditions and limited number of validation data sets. Now when the two-year MethaneCAMP project is finishing, we will demonstrate the recent improvements in the observation capacity over the polar regions by assessing and optimising methane SWIR and TIR retrievals at high northern latitudes. Moreover, the importance of AirCore reference observations of methane profiles in the varying polar vortex conditions will be highlighted. We will analyse the long-term methane trends in the northern high latitudes and permafrost regions by using satellite observations and inverse modelling. We aim to demonstrate the potential of using satellite observations of methane together with modelling and surface observations in analysing spatial and temporal changes of the Arctic methane. Detection of methane hot spots will also be mentioned.In MethaneCAMP project our focus has been on Sentinel 5P/TROPMI, GOSAT, GOSAT-2 and IASI XCH4 observations and GHGSat emission estimates. In this presentation we summarise the results of the project and discuss how the outcomes can be utilised in the AMPAC working group activities.
Investigating the impact of lianas on global tropical forests
Authors: Verbeeck Hans , Krishna Moorthy Sruthi Moorthy , Calders Kim , Meunier Félicien
Published: March 2024

Lianas (woody vines) are an iconic feature of tropical forests as they represent on average 25% of all woody stems. Lianas are structural parasites that use the stems of self-supporting plants to reach the top of the canopy. From there, they strongly compete with trees for above- (light) and below-ground (water nutrients) resources. Despite their importance, lianas are completely neglected by terrestrial models. To fill this gap, we developed the first mechanistic representation of lianas in a state-of-the-art vegetation model, the Ecosystem Demography model version 2 (ED2.2). Model simulations revealed the critical role of liana for forest biogeochemical cycles (e.g., tree gross and net productivity decreases when lianas are present with the magnitude of the reduction varying with liana abundance) but also for the energy balance (e.g., lianas increase forest albedo and buffer the microclimate of forest understorey).  In addition, we used a combination of terrestrial lidar scanning and a meta-analysis of field and drone observations of tree shape and structure to evaluate the impacts of lianas on tree allometries. In total, we gathered 45,000+ observations of individual tree height, 1.000+ observations of tree crown areas and 150+ tree quantitative structure models over more than 40 sites spread over the tropics, together with liana infestation levels. Those datasets converged to identify a key role of lianas on the shape and structure of tree in tropical forests, independently of the tree species. Liana heavy infestation was responsible for a strong reduction of tree height (-10.7%), crown area (-12.6%), branch length (-45.9%), and overall aboveground carbon stocks (-19.6%). We estimated the global potential liana impact on aboveground tree carbon stocks to be 13.5 Tg over the tropics, or about 7% of the total tropical forest biomass. 
Latent Neural Mapping for Hydrological Data Assimilation in Flood Prediction
Authors: Wang Kun , Cheng Sibo , Piggott Matthew , Dance Sarah L , Arcucci Rossella
Published: March 2024

Floods are one of the most frequent and severe natural disasters, and it is important to be prepared to predict them. Accurate prediction of floods requires the provision of accurate estimates of river discharge. Data assimilation (DA) as a technique for integrating background fields and observations can be a helpful solution to improve the accuracy of the river discharge prediction. DA can be a highly effective technology, however, when DA is performed on a large amount of data or high dimensional data, it results to be computationally very expensive, which is inappropriate for flood prediction, where timely results are required. Also, DA is used to merge data from diverse sources of information and, when the background fields and the observations are not from the same place, e.g. the observations are sparse, data must be interpolated on different grinds which increase the errors’ accumulation. In this work, latent neural mapping is designed to mitigate problems related to errors propagation and computational cost. We integrated DA with neural network (NN) and the resulting model helps on saving computational cost and solve the problem of sparse observation. Convolutional NN are employed to build a mapping function which converts data from the background space to the observation space (and vice versa). We tested the model with real data and flooding events in the UK. Data provided by the National River Flow Archive (NRFA) served as observations and the data provided by the European Flood Awareness System (EFAS) served as background fields. The Result shows that the accuracy is improved by 54.4% in MSE and the runtime of the model in 50s for 300 iterations. 
Implications of changes in range expansion behavior of salt marshes and mangroves on dominant wetland cover and morphodynamics
Authors: Wei Yizhang , van Maanen Barend , Xie Danghan , Zhou Zeng , Schwarz Christian
Published: March 2024

Coastal wetlands, salt marshes and mangroves, fulfil important functions for biodiversity conservation and coastal protection, which are inextricably linked to interactions between hydrodynamics, sediment transport and ecology the so-called eco-geomorphological feedback. However, range expansion patterns of salt marshes and mangroves are changing due to both human influences and global change. Human driven introduction of salt marsh species for erosion mitigation starting in the last century e.g. (Europa and China) are influence natural mangrove habitats and its implications are still unfolding. Conversely, within the last decades, a climate change induced ubiquitous trend of mangrove encroachment on salt marshes has been observed globally in the mangrove-salt marsh transition zones, e.g. the southern USA, South America, Australia, New Zealand and South Africa. Here we present a novel eco-morphodynamic model able to predict species-species interactions, i.e. competition and facilitating, sediment transport on morphodynamics. The aim of our study is to predict competitive outcomes of mangrove-saltmarsh interactions resulting from the interaction of species-specific growth and stress tolerance, and additional natural and climatic factors. First results indicate the competitive outcome to be context dependent on the relative growth properties of the mangrove and salt marsh species in question. Thereby providing highly need to context to interpret implication on shifts in species ranges on morphodynamic wetland development. 
Mapping Fossil Ties: Decentralised research into ties between universities and the fossil fuel industry
Authors: Sachisthal Maien , Pereira Aaron , Knoester Linda
Published: March 2024

Universities are under increasing scrutiny from students, staff and society about their ties with the fossil fuel industry. Such ties include research cooperations and commissions, influence and participation in study programmes, sponsoring of students and student societies, sponsored professorships and staff ancilliary activities, presence at careers fairs and alumni networks. For fair and open discussion on what relationships between universities and the fossil fuel industry are appropriate, such relationships must be transparent - currently this is not the case. In the Netherlands, the Mapping Fossil Ties coalition - a research coalition of student and staff activists, NGOs and independent investigators - map these "fossil ties" and track the influence of fossil fuel companies in universities. We use a variety of methods: freedom of information (FOI) requests to universities and funding bodies, web scraping, and decentralised, crowdsourced information gathering on campus. From this, we could build a fuller picture of how Dutch academia interacts with and is influenced by the fossil industry, and can identify hidden, yet problematic ties. The collaborations, news coverage, and state of the debate are continually updated on a web portal (mappingfossilties.org) for the use of investigative journalists, (activist) student and university staff, NGOs, policymakers, and the public. In this talk we present our methodology, the impact that this research has had on the Dutch public debate, how this research underpins student and staff activism, and points for improvement and learning. Finally we discuss how we are replicating such research in other countries, and how others can do so too.
Active fault growth with geologic inheritance –through the lens of earthquake rupture
Authors: Liu-Zeng Jing , Liu Zhijun , Liu Xiaoli , Milliner Chris , Padilla Alba M. Rodriguez , Xu Shiqing , Avouac Jean-Philippe , Yao Wenqian , Klinger Yann , Han Longfei , Shao Yanxiu , Yan Xaiodong , Aati Sarif , Shao Zhigang
Published: March 2024

Fault maturity has been proposed to exert a first-order control on earthquake rupture, yet direct observations linking individual rupture to long-term fault growth are rare. The 2021 Mw 7.4 Maduo earthquake ruptured the east-growing end of the slow-moving (~1 mm/yr) Jiangcuo fault in north Tibet, providing an opportunity to examine the relation between rupture characteristics and fault structure. Here, we combine field and multiple remote sensing techniques to map the surface rupture at cm-resolution and document comprehensively on-fault offsets and off-fault deformation. The 158 km-long surface rupture consists of misoriented structurally inherited N110°-striking segments and younger optimally oriented N093°-striking segments, relative to the regional stress field. Despite being comparatively newly formed, the ~N093°-striking fault segments accommodate more localized strain, with up to 3 m on-fault left-lateral slip and 25-50% off-fault deformation, and possibly faster rupture speed. These results are in contrast with previous findings showing more localized strain and faster rupture speed on more mature fault segments; instead, our observations suggest that fault orientation with respect to the regional stress can exert a more important control than fault maturity on coseismic rupture behaviors when both factors are at play.
Assessment of TROPOMI HCHO Vertical Columns: evaluating the use of CAMS vertical profiles and new TROPOMI surface albedo climatologies for air mass factor determination
Authors: De Smedt Isabelle , Yu Huan , Theys Nicolas , Heue Klaus-Peter , Compernolle Steven , Pinardi Gaia , Hedelt Pascal , Tilstra Gijsbert , Danckaert Thomas , Vigouroux Corinne , Langerock Bavo , Loyola Diego , Richter Andreas , Boersma Folkert , Van Roozendael Michel
Published: March 2024

The ESA Climate Change Initiative (CCI) Ozone and Aerosols Precursors project is developing long-term climate data records (CDRs) of the Global Climate Observing System (GCOS) Precursors for Aerosol and Ozone Essential Climate Variables. These precursors include short-lived atmospheric trace gases such as formaldehyde (HCHO), glyoxal (CHOCHO), nitrogen dioxide (NO2), sulphur dioxide (SO2), carbon monoxide (CO), and ammonia (NH3). The project aims to create consistent and harmonized CDRs from multiple satellite missions, including GOME, SCIAMACHY, GOME-2, OMI, TROPOMI, IASI, and MOPITT.This work presents selected findings of a round robin exercise conducted for UV-VIS retrievals. We focus on two key factors that influence HCHO air mass factor determination: the surface albedo climatology and the model a priori profiles. The impact of these factors on the HCHO vertical columns is evaluated by comparing the use of recent auxiliary datasets. Results are presented for TROPOMI HCHO columns and compared to the operational product.The recent reprocessing of TROPOMI Level 1 data has enabled the development of new albedo climatologies in the UV, offering a finer spatial resolution than the previously used OMI albedo climatology. Additionally, we evaluate the use of a priori vertical profiles from the CAMS reanalysis dataset (spanning the 2003-2022 period) instead of the current TM5-MP profiles used in the TROPOMI operational product. We assess the impact of these alternative datasets on the TROPOMI HCHO vertical columns and on their validation towards ground-based data.The generation of the ESA CCI HCHO CDR will be based on these findings. This comprehensive assessment not only contributes to the ongoing improvement of TROPOMI data quality but also provides deeper insights into the factors influencing HCHO vertical columns.
Boulder-induced Turbulence Drives Shift in Seismic Frequency
Authors: Nativ Ron , Laronne Jonathan , Turowski Jens , Chang Jui-Ming , Yang Ci-Jian , Hovius Niels , Chen Wen-Sheng , Chang Wen-Yen
Published: March 2024

Turbulent flows capable of mobilizing sediments, despite being studied over the past 100 years, continue to constitute an elusive process. In environmental seismology, seismic waves generated by the interplay of surface processes and the Earth offer a key to unraveling the dynamics of river processes. We studied the seismic signals emitted during floods in two tributaries with large boulders. Early findings indicated an unusually high dominant seismic frequency, reaching 2-4 times the frequency observed in nearby channels with smoother beds. Consistent anomalous high-frequency content during times without sediment transport prompts our hypothesis that turbulence is the key process driving the frequency shift. We hypothesized that the most energetic turbulent eddies, dominating the signal, decrease in size in response to the boulder-influenced constrained flow geometry, and we argue that this effect possesses a first-order control on the frequency shift. A frequency scaling law with boulder spacing, approximating boulder-induced eddy size, shows good agreement with our field data. The dynamics of the eddies under changing flow velocity are well predicted by a power law function of seismic frequency with water depth. The trend breaks at the onset of bedload transport, indicating that energy is dissipated through the partitioning between turbulence and sediment transport. Our study emphasizes that seismic frequency effectively records the dominant morphology and fluvial processes, revealing the intricate interaction between roughness and seismic energy.
Characteristics and mechanism analysis of geothermal resources innorthern Jianghan Basin
Authors: Wan Xiaofan , Shen Chuanbo , Ge Xiang
Published: March 2024

The geothermal energy in the northern Jianghan Basin is considered hydrothermal geothermal resources. Heat generation condition and thermal conduction mechanism are crucial factors affecting the migration of geothermal fluid. However, it is not clear about the controlling factors of geothermal distribution and formation modes in this region. To explore the spread, accumulation and preservation characteristics of geothermal resource in the northern Jianghan basin, the deep geological backgrounds and tectonic characteristics of the target area are analyzed. Also, the genetic model is conceived during the research to have a acquaintance with the process of geothermal energy evolution. Traditional methods, for example the inversion of gravity, magnetic, and electric, are applied to recognize the concealed rock. Besides, numerous data, including seismic, oil and gas wells, geothermal wells and hydrochemical composition, is used to analyze the characteristics of geothermal fields, properties of deep rock mass, structures of geothermal reservoirs and thermal conductivity of faults. The results show that the regional uplifts and depressions control the distribution of geothermal resources. In addition, what play a pivotal role in the connection between deep heat sources and upper prospecting reservoirs are boundary faults of the basin. What’s more, neotectonic activities of faults are beneficial channels for heat and water conduction. On the basis of above researches, the model of geothermal distribution related with fault systems is well established, confirming that geothermal resources are mostly distributed in conjunction zones of differed faults. The findings of this work provide scientific evidence for discovering other geothermal favorable areas in the Jianghan Basin.
Flooded mangroves as a record of sediment accretion and carbon burial rates during Holocene sea-level rise in Rio Lagartos, northern Yucatan Peninsula, Mexico
Authors: Diaz Asencio Misael , Brenner Mark , Suárez-Mozo Nancy , Curtis Jason , Solís Corina , Cejas-Rodríguez María , Daessle Luis W. , Papiol Vanesa , Enriquez Cecilia
Published: March 2024

Coastal zones are dynamic regions that change over time because of both natural processes and human activities. Such changes occur over different time scales, from days (e.g., those caused by hurricanes) to millennia (e.g., those caused by sea level rise). Sediments in these zones preserve information about past environmental changes, which can be inferred from shifts in the composition and accumulation rate of accrued deposits. We investigated the transformation of an intertidal zone dominated by mangroves into an underwater system characterized by carbonate accumulation. We used stratigraphic records of sediment cores to estimate organic carbon burial rates during the intertidal phase (flooded mangrove), which existed more than 3000 years ago. We collected sediment sequences using a piston corer in the eastern sector of the coastal Río Lagartos Lagoon, northern Yucatán Peninsula, Mexico, which, because of its shallow depth and morphology, is very sensitive to drivers of change. Organic matter was relatively higher at depth in the core (15-50 cm), but upper sediments (0-15 cm) were dominated by carbonate. AMS 14C ages on total organic matter were obtained at two depths. The 14C age at 40-45 (3498 ± 35 years BP) was only slightly older than the age at 25-30 cm (3312 ± 35 years BP). The mean organic carbon (OC) burial rate in the interval 25-40 cm was 53 g m-2 yr-1, a value in the range reported for recent OC accumulation in mangroves of Yucatán. Based on the age of the 25-30 cm section and the current water depth in the area (~1 m), we estimate an increase in the sea-level rise of 0.4 mm yr-1 over the last 3000 years, lower than values reported for the area using estimates of recent accretion of sediments. This work highlights the high OC burial rates in ancient mangroves, which today are flooded and are areas that are accumulating carbonate. Our findings illustrate the importance of conserving mangrove-dominated lagoon systems on the Yucatán Peninsula, which are important carbon sinks.
Validation of the Diurnal Amplitude Variations for Freeze-Thaw (DAV-FT) algorithm with the National Ecological Observatory Network (NEON) soil temperature data
Authors: Lv Shaoning
Published: March 2024

Knowing the Freeze-Thaw (FT) state/ice content/freezing front depth of the land surface is essential for many aspects of weather forecasting, climate, hydrology, and agriculture. Microwave L-band emission contains rather direct information about the FT-state because of its impact on the soil dielectric constant, which determines microwave emissivity and the optical depth profile. However, current L band-based FT algorithms need reference values to distinguish between frozen and thawed soil, which are often not well known. We present a series of new frozen soil detection algorithms based on the daily variation of the H-polarized brightness temperature. Exploiting the daily variation signal allows for a more reliable state detection, particularly during the transition periods, when the near-surface soil layer may freeze and thaw on sub-daily time scales. The new algorithms explore and prove that we can get the Freeze-Thaw (FT) state/ice content/freezing front depth of the land surface with a delicate analysis of the L-band passive brightness temperature signals. These studies are expected to extend L-band microwave remote sensing data for improved FT detection.
The Changing-Atmosphere Infra-Red Tomography Explorer (CAIRT) Earth Explorer 11 candidate mission
Authors: Funke Bernd , Chipperfield Martyn , Errera Quentin , Friedl-Vallon Felix , Godin-Beekmann Sophie , Hoepfner Michael , Hoffmann Alex , Malavart Alizee , Osprey Scott , Polichtchouk Inna , Preusse Peter , Raspollini Piera , Sinnhuber Björn-Martin , Verronen Pekka , Walker Kaley
Published: March 2024

The Changing-Atmosphere Infra-Red Tomography Explorer (CAIRT) is currently in Phase A as one of two final candidates for ESA’s Earth Explorer 11. As a Fourier transform infrared limb imager, CAIRT will observe simultaneously from the middle troposphere to the lower thermosphere at high spectral resolution and with unprecedented horizontal and vertical resolution. With this, CAIRT will provide critical information on (a) atmospheric gravity waves, circulation and mixing, (b) coupling with the upper atmosphere, solar variability and space weather and, (c) aerosols and pollutants in the upper troposphere and  lower stratosphere. In this presentation we will give an overview of CAIRT’s science goals and the expected mission performance, based on latest results from feasibility studies performed during Phase 0. 
The Leaky Cauldron; an experimental study of the icy plumes of Enceladus
Authors: Bourgeois Yael , Giordano Fabrizio , Cazaux Stephanie , Schrijer Ferry
Published: March 2024

The discovery of vast subsurface oceans hidden under kilometers of ices on icy moons in our Solar System has sparked worldwide interests in ascertaining their potential habitability. In the case of Saturn’s moon Enceladus, supersonic plumes of water vapour and icy grains have been observed by the Cassini mission spewing from the surface, giving us indirect knowledge of the composition of this subsurface ocean. The exact mechanisms of the plumes however, and their effect on the composition of the ejected matter has yet to be clearly understood. The focus of this study is to experimentally investigate physical characteristics of the plumes located at the South Polar Terrain (SPT) of Enceladus. Using facilities at TU Delft faculty, we simulate experimentally the topology of the ice crevasses and the subsurface ocean with a narrow channel mounted atop a liquid water reservoir placed inside a vacuum chamber. We inquire upon the dependence of the channel walls temperature on the plume’s exhaust velocity. Using a straight channel, our results show that colder wall temperatures enable a saturated water vapour flow with a minima 1.5-3 % solid fraction and vent velocities reaching around 400-500 m/s. The data ranges for velocities and solid fraction extrapolated from the Cassini data (550-2000 m/s and 7-70 %) thus cannot be explained by straight channel models. Using a channel with an expansion ratio of 1.73 however, the measured supersonic plume velocity becomes comparable to some of the in situ Mach number determined at Enceladus. Using a method based on the energy conservation law, it is possible to extrapolate from our experimental data some plausible geometries of the ice crevasses of Enceladus. This work lays the ground work for a coming comprehensive parametric study of the channel geometry and its effect on exhaust Mach number, temperature and solid fraction.
Structural control on aseismic and seismic slip interactions during the 2020 SSE in the Atacama region, Chile.
Authors: Molina Diego , Münchmeyer Jannes , Radiguet Mathilde , Socquet Anne , Doin Marie-Pierre
Published: March 2024

While subduction earthquakes are widely recognized for releasing seismic slip, aseismic slip can also be hosted on the megathrust by the occurrence of postseismic phase or Slow Slip Events (SSEs). SSEs have been reported along several subduction zones, preferably on the deeper zone and usually lasting months or even years (Draguert et al., 2001). Notably, in the Chilean subduction zone, deep SSEs have been observed in only a reduced area in Central Andes, specifically close to the Copiapo city. Recent studies report that this area is prone to host regular SSEs with a recurrence time of ~5 years and variable duration (Klein et al., 2021), which was confirmed by a new detected SSE in 2020 and 2023.Notably, during the 2020 SSE, a seismic crisis with a main shock of Mw 6.9 took place on the zone (September 2020), likely provoking an interaction between the different slip modes.  In this work, we attempt to enhance the characterization of the temporal and spatial pattern-evolution of the SSE to elucidate whether there was a trigger mechanism for the seismic crisis or if the earthquake affected the SSE evolution.To describe the seismic behavior of the area, we recur to the analysis of distinct data sets. On one hand, GNSS stations deployed by different institutions are used to characterize the temporal evolution and amplitude of the 2020-SSE and respective seismic crisis. On the other hand, the spatial pattern is recovered by InSAR data recorded by Sentinel-1 mission. Additionally, a seismicity catalogs coming from machine learning approach is used to investigate aseismic-seismic interactions.Our analysis shows that the 2020 SSE triggered the seismic sequence in September of that year. We also observed that the aseismic deformation migrates, resulting in a total cumulative slip pattern similar to another SSE detected in 2014. Remarkably, our study evidences a clear segmentation along dip and strike affecting both, aseismic and seismic slip, which correlates with gravity anomalies.This study suggests a tectonic control on the slip behavior characterizing the area and highlights the cinematic between slow and fast earthquakes hosted along the plate interface.  
When Metadata crosses Borders - Enabling Repository Providers with Joint Forces in Earth System Sciences
Authors: Henzen Christin , Degbelo Auriol , Grieb Jonas , Heß Robin , Klammer Ralf , Koppe Roland , Lorenz Christof , Müller Claudia
Published: March 2024

Research data in the Earth System Sciences (ESS) are managed in diverse repositories with varying aims, publishing, and curation approaches, as well as technical solutions. The resulting heterogeneity often hampers implementing interoperability and harvesting concepts. From the researchers' perspective on integrative data-driven research questions across repository borders, this leads to ineffective search and reuse of the data. We consider it is vital to train researchers to provide high-quality FAIR data and metadata. However, it is even more important to enable repository providers to act as multipliers, as this enables them to provide researchers with suitable repository solutions. This can be done, for example, by implementing fit-for-purpose metadata schemas and interfaces.In Germany, several initiatives serve as umbrellas for joint activities with ESS repository providers. In collaboration of the German national data infrastructure for Earth System Sciences (NFDI4Earth) and the Helmholtz Metadata Collaboration (HMC), we have developed a roadmap that enables repository providers to meet the needs of researchers and technical requirements. As an initial step, we developed recommendations in a community-driven process across NFDI4Earth and HMC. These recommendations provide common steps to foster interoperability, particularly with regard to search and harvesting. Moreover, we have identified a first set of use cases for specific types of ESS data that complement the developed recommendations, e.g. underway measurements of seawater temperature. Through regular updates in the form of community consultations and workshops, we will identify further community needs, as well as support updates and developments of metadata standards, e.g. the implementation of underway measurements in GeoDCAT. In this contribution, we will describe our recommendations, use cases, and lessons learned from the activities for a community-driven process to enable repository providers.
China National Water Model (CNWM): Revolutionizing Hydrological Forecasting
Authors: Shu Lele , chen Hao , Meng Xianhong
Published: March 2024

The China National Water Model (CNWM) introduces a pioneering approach to hydrological forecasting in China, integrating the Simulator of Hydrological Unstructured Domains (SHUD) with advanced deep learning techniques. This paper presents the CNWM's conceptual framework and prototype, emphasizing its capability for real-time, accurate hydrological predictions. The CNWM is self-running and self-updating, designed to predict streamflow, groundwater levels, soil moisture, and flash flood risks. It leverages real-time data from the China National Hydrology-Rainfall Information System, enhancing its utility in disaster prevention and management. The prototype demonstrates the CNWM's potential, laying the groundwork for a comprehensive, nationwide hydrological forecasting system. This research marks a significant stride in hydrological modeling, showcasing the impact of interdisciplinary collaboration in environmental management.
Deciphering the force history of 2021 Chamoli rockslide
Authors: Palliath Athul , Paul Himangshu , Rao N Purnachandra , Vempati Venkatesh
Published: March 2024

Landslides are a significant hazard, particularly for those living in mountainous regions where the terrain is steep and unstable. Unfortunately, continuous monitoring of landslides is challenging due to their unpredictable nature. However, recent advancements in high-quality, dense broadband seismic networks have made it possible to study the spatial and temporal evolution of mass wasting processes through the analysis of seismic signals. The 2021 Chamoli rockslide which originated from a glaciated ridge of the Ronti Mountain in the western Himalaya caused severe damage to a hydropower project in downslope region and a casualty of about 80 people. CSIR-National Geophysical Research Institute established a regional seismic network in the Uttarakhand Himalaya which provides a great scope to understand this event in greater detail. We have performed dynamic inversion of the long period seismic waves generated by the rockslide to derive its force history. We used multistation data from Uttarakhand regional seismic network. We used IRIS syngine to generate Green’s function based on ak135 velocity model. Long period seismic waveforms from 6 stations within a distance of 80 km were chosen to perform inversion based on the signal to noise ratio and azimuthal coverage. The inversion is done using python package called lsforce. We reconstruct the force time history of the landslide, from the initial detachment of the rock mass to its impact on the ground. The peak upward vertical force corresponds to the detachment and peak downward vertical force corresponds its  the imapct  onto the ground. The result agrees with the centroid single force inversion done for the phases of detachment and impact of the landslide. The result obtained from force time history can be used to constrain parameters for the numerical simulation of the landslide to understand its dynamics in detail.  
Projecting future permafrost thaw and subsidence driven infrastructure damage in the discontinuous permafrost zone
Authors: Farquharson Louise , Nicolsky Dmitry , Calif Monika , Schmidt Jennifer , Romanovsky Vladimir , Douglas Thomas
Published: March 2024

Permafrost thaw, ground-ice melt, and associated ground settlement pose significant hazards to northern communities and industry. Thaw of permafrost affected soils can decrease bearing capacity while settlement due to ground ice melt can cause ground collapse (thermokarst) and localized flooding. Here, explore ground ice distribution and potential for thaw induced settlement in the Fairbanks North Star Borough (FNSB), located in an area of discontinuous permafrost in Interior Alaska, USA. Pleistocene-Holocene sediment deposition, ice wedge development, and subsequent reworking due to thaw and hillslope processes have left a complex mosaic of cryolithological conditions that make thaw-related hazards a challenge to predict. The Borough is home to critical infrastructure including two military bases, a university, several gold mines, and the Trans Alaska Pipeline. We created a permafrost hazard map by combining modelled ground ice distribution with projections of ground temperature through to 2090 using the GIPL 2.0 model for key ecotypes in the area. From this we were able to infer temperature dynamics, active layer deepening, talik development, and the potential for thermokarst degradation for IPCC Representative Concentration Pathway scenarios 4.5 and 8.5 through to 2090. We established ground ice distribution through a combination of existing geologic maps, numerical modeling, lidar derived thaw feature maps, and industry bore holes.  To extrapolate ground ice values from the representative sub-sample of ~ 2000km2 to the entire Borough we utilized a gradient-boosted decision tree aggregate model.  Across the FNSB 23 % of the terrain is underlain by the high ground ice class, 10% medium, 4% low, 44% negligible, and 17% of the region is unaffected. High ground ice content underlines 23 % powerlines, 21% of roads and 4% of critical infrastructure (schools, hospitals, power plants etc.). Future projections of subsidence in areas of black spruce forest under RCP4.5 and 8.5 for areas respectively show that areas of high ice content could see subsidence of up to 5 and 10 meters respectively by 2090. Subsidence values for a range of topographic locations were calculated. Results from this study may help the FNSB, land managers, and homeowners best prepare and plan for the impacts of climate change in the Fairbanks region and potentially provide a hazard mitigation and climate change adaptation guides for other sub-Arctic communities.
Discovery of lithospheric drip explains topographic rejuvenation of the Uinta Mountains, USA
Authors: Smith Adam , Fox Matthew , Miller Scott , Anderson Leif
Published: March 2024

Densification at the base of thickened crust drives lithospheric dripping or delamination. Mountain ranges form due to crustal thickening, and so represent locations where dripping and delamination are likely to occur. Recent studies have implicated dripping continental crust with a variety of different surface expressions, from driving surface uplift to initiating rifting, highlighting the uncertainty associated with our ability to predict the surface consequences of dripping continental crust. The Uinta Mountains in Utah formed during the Laramide orogeny, and despite this period of crustal shortening ending ~50 mya, the elevation of the range, and the form of the river networks draining the range suggest the range has undergone topographic rejuvenation. To investigate the cause of this rejuvenation, we extract map of recent surface uplift from the river networks of the Uintas, and use previously published seismic tomography to investigate the structure of the mantle beneath the range. We identify dripping lithospheric crust beneath the Uintas, and, using a simple isostatic model, are able to reconcile the observed surface uplift with a prediction of surface uplift based on isostatic compensation. The agreement between our observations and our predictions allow us to present a compelling case for delamination driven surface uplift of the Uintas, and show that simple isostatic compensation can explain the surface expressions of delaminated crust. Our observations therefore have important implications for the history of the Uinta Mountains and more generally for our understanding of the long-term evolution of the continents. 
Selective transport and deposition of magnetic particles during speleothem growth
Authors: Font Eric , Brás Ana Raquel , Feinberg Joshua , Egli Ramon , Reboleira Ana Sofia , Melo Rui , Fonseca Paulo
Published: March 2024

During the last decades, advances in the field of speleothem’s magnetism opened a new door to investigate high-resolution and short-lived features of the Earth’s magnetic field. Due to the rapid precipitation of calcite/aragonite, the lock-in time of the detrital remanent magnetization resulting from the physical alignment of the magnetic minerals parallel to the Earth’s magnetic field is acquired almost instantaneously. The magnetic particles trapped into the speleothem usually originate from the soils capping the cave and are transported into the cave by dripwaters. Authigenic magnetic particles may also precipitate under conditions likely to prevail during speleothem growth. Here we investigate the magnetic mineralogy of a stalagmite from the Gruta da Ceramica of Central Portugal. We also analyzed the host carbonate, the cave sediments and the soils capping the cave. We measured concentration- and grainsize-dependent magnetic proxies, including natural remanent magnetization, anhysteretic remanent magnetization, isothermal remanent magnetization, mass specific magnetic susceptibility, FORC and hysteresis curves.  Results show that magnetic and hematite are the main magnetic carriers in all samples. A gradual enrichment of hematite relative to magnetite is observed following the transportation path from the soils to the cave sediments up to the stalagmite. The higher contribution of hematite relative to magnetite in the speleothem may reflect precipitation of authentic hematite during speleothem growth or the selective transport of finer particles from the soil to the cave.   Acknowledgments: This work was funded by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (refs. PTDC/CTA-GEO/0125/2021), (PIDDAC) – UIDB/50019/2020, UIDP/50019/2020 and LA/P/0068/202
The role of salt tectonics in the occurrence of the 2021 Central Adriatic seismic sequence
Authors: Scognamiglio Laura , Di Luccio Francesca , Palano Mimmo , Marchetti Alessandro , Dasović Iva , Mustać Marija , Magnoni Federica , Artale Harris Pietro , Casarotti Emanuele , Polonia Alina , Gasperini Luca , Dannowski Anke , Kopp Heidrun
Published: March 2024

On 27 March 2021 a three-months lasting seismic sequence struck the Central Adriatic Basin, part of Adria that is considered a relatively undeformed plate since recent times. Analyzing the waveform data acquired by the Italian and Croatian seismic networks, we computed the location parameters of 160 earthquakes and the focal mechanisms of the Mw5.2 mainshock and larger aftershocks. Most events align along a WNW-ESE, 30 km long, narrow belt. They form two clusters between 0-3 km and 4-14 km of depth, separated by a 1-2 km thick aseismic zone. Based on literature data, we suggest that such a seismic gap corresponds to a ductile salt layer, which constitutes the primary control factor for the evolution of the 2021 earthquake distribution. Moreover, the presence of a salt layer explains well the relatively high Vp/Vs ratio of 1.83 in the sediment rocks surrounding the salt bodies, as also observed in similar tectonic settings. We suggest that the seismogenic fault likely responsible for the 2021 events is an inherited SW-dipping normal fault, reactivated with prevalent reverse kinematics in response to the regional compressive stress. These results, and the recognition of a specific role of salt deposits in focusing deformation and seismogenesis represent a novel contribution to the long-standing problem of seismic hazard assessment of the Central Adriatic Basin, where moderate to large events could have devastating impacts along the highly populated coasts.
Enhanced Energy Conversion by Turbulence in Collisionless Magnetic Reconnection
Authors: Zhou Meng , Jin Runqing , Yi Yongyuan , Man Hengyan , Zhong Zhihong , Pang Ye , Deng Xiaohua
Published: March 2024

Magnetic reconnection and turbulence are two of the most significant mechanisms for energy dissipation in collisionless plasma. The role of turbulence in magnetic reconnection poses an outstanding problem in astrophysics and plasma physics. It is still unclear whether turbulence could modify the reconnection process by enhancing the reconnection rate or energy conversion rate. In this study, utilizing unprecedented high-resolution data obtained from the Magnetospheric Multiscale spacecraft, we provide direct evidence that turbulence plays a vital role in promoting energy conversion during reconnection. We reached this conclusion by comparing magnetotail reconnection events with similar inflow Alfven speed and plasma β, but varying amplitudes of turbulence. The disparity in energy conversion was attributed to the strength of turbulence. Stronger turbulence generates more coherent structures with smaller spatial scales, which are pivotal contributors to energy conversion during reconnection. In addition, we find that turbulence has negligible impact on particle heating, but it does affect the ion bulk kinetic energy. These findings significantly advance our understanding of the relationship between turbulence and reconnection in astrophysical plasmas.
Using machine learning approaches for predicting suspended sediments in alpine catchments – uncertainties and limitations
Authors: Frasnelli Thomas , Schöber Johannes , Pesci Maria , Förster Kristian , Achleitner Stefan
Published: March 2024

Hydropower generation and the associated sediment management is one out of different water related services that are subjected to hydrological changes over time. Thus, the assessment and prediction of the sediment transported from catchments at varying temporal and spatial scales was and is an important task in hydraulic engineering. In this study, we focus on alpine catchments feeding a reservoir for hydropower production. Aim was to simulate and predict the suspended sediment input, which accounts for the vast majority of sediment loads.The selected catchments, Pitzbach and Fagge, are part of the hydropower system Kaunertal Valley (Tyrol/Austria), operated by the TIWAG. The available measurements include discharges and turbidity/suspended solids contributing to the sedimentation of the Gepatsch reservoir. The discharge time series cover several decades, whereas turbidity was only measured during the recent years.A combination of a process-based water balance modelling and a data driven approach to simulate sediment fluxes was combined to simulate extreme events and years as well as past periods where no material transport was measured.For the two sub-catchments, different machine learning approaches were used to mimic suspended sediment transport, based on an available 11-year (2008-2018) long timeseries. Specifically, feed-forward neuronal networks (FFNN) and long short-term memory networks (LSTM), were tested and compared using different input combinations to identify the most suitable models for the respective catchment area.For further validations the models were exanimated on a short “future” period (2019-2022), which was not part of the calibration. The model performance was evaluated for this time series, having a special focus on periods with exceptionally high transported sediment loads. For past periods (back until 1970), only discharge and reduced number of meteorological stations are available. Similarly, the models were applied to these periods in order to calculate sediment transport time series. On the one hand, a solely data driven approach using measured discharge and meteorological time series was tested. Beyond that, results from a process based hydrological model were used, aiming to cover also periods with gaps in the discharge data.Overall, the simulations allowed to quantify the uncertainties associated to such modelling chains, when using them to describe sediment fluxes at different temporal scales.
Effect of brick sand on the soil water balance in permeable soils
Authors: Mähr Andreas , Rauch Hans Peter , Eitzinger Josef , Weihs Philipp , Hörbinger Stephan
Published: March 2024

In the course of climate change, the framework conditions for agricultural production will change significantly. The ability of the soil to absorb water quickly and efficiently while at the same time storing as much water as possible for plants to use is a prerequisite for maintaining future agricultural production potential.The aim of this study was to investigate the application of recycled brick sand in agricultural soils with regard to its water absorption and storage capacity and thus to improve the efficiency of water utilisation. The influence of different precipitation intensities on the water storage capacity was analysed.In order to determine the influence of brick sand on the soil water balance, an experiment was carried out with nine small lysimeter systems. The lysimeters were all filled with soil samples from a vineyard in eastern Austria, whose soil has a high sand fraction and low clay mineral content. Three lysimeters were used as a reference and contained no brick sand. In three others, a mixture of soil sample and 10 % brick sand was used and in three others a mixture of soil sample and 30 % brick sand was applied. A 3-phase test was then carried out. The first phase was used to set a volumetric water content that was as constant as possible in all samples. The second phase was the simulation of a 10-millimetre precipitation event, followed by the third phase, the simulation of a 20-millimetre precipitation event. During the precipitation simulation, the amount of water corresponding to the precipitation intensity was applied to the lysimeter systems and the volumetric water content of the samples was recorded. Control values were determined using soil moisture sensors.The results showed that the addition of brick sand enabled the soil to store more water over time than the sample without brick sand. The simulations also showed that the amount of brick sand added made a difference in how the water storage capacity changed. Shortly after the rainfall simulation, the lysimeters with 30 % brick sand were able to store the water better. Towards the end of the precipitation simulation, the difference in stored water between the lysimeters with 30 % brick sand content and those with 10 % brick sand content became smaller, and in the 20 millimetre rainfall simulation, the lysimeters with 10 % brick sand content stored more water from halfway through the observation period. The results showed that the use of brick sand as a measure to improve the soil water balance has a high potential, however, the amount of brick sand applied must be adapted to the soil to be treated. These adjustments concern parameters such as grain size distribution and pore distribution, as these have a decisive influence on the water storage capacity.