bluuebunny/crossref_metadata_2025 huggingface dataset:
Microfacies controlling the preservation of small shelly fossils from the lower to middle Cambrian of North China
Authors: Hu Yazhou , Topper Timothy , Strotz Luke , Liang Yue , Liu Fan , Fu Rao , Song Baopeng , Wang Zhao , Zhang Zhifei
Published: March 2024

Small shelly fossils have long been recognized as important evidence of both metazoan evolution and biomineralization during the Cambrian radiation. The marked decline in the occurrence, diversity and abundance of small shelly fossils in the middle to late Cambrian, when compared with the early Cambrian, has often been regarded as representative of a closing phosphatization window. Small shelly fossil-like assemblages have, however, been sparsely reported from the entirety of the Phanerozoic, indicating preservation of small shelly fossils is possible outside of the Cambrian. To identify possible factors enhancing small shelly fossil preservation, five microfacies (normal bioclastic limestone, flat-pebble conglomerates with bioclasts, hummocky cross-stratified grainstones with bioclasts, bioclastic grainstone in hardgrounds and glauconite bioclastic wackestone-packstone) from the Houjiashan, Mantou, Maozhuang, Xuzhuang and Zhangxia formations, Cambrian Series 2 to Miaolingian in North China are compared to assess for differences in preservation potential. The majority of extracted small shelly fossils from the studied section come from normal bioclastic limestones, but diversity is generally low and ornament is poorly preserved (except for original organophosphatic shells). The diversity of shelly fossils in flat-pebble conglomerates with bioclasts and hummocky cross-stratified grainstone with bioclasts are similar to normal bioclastic limestone, but with a greater abundance of articulated brachiopods. Bioclastic grainstone from hardgrounds facilitate some soft tissue preservation but the overgrowth of apatite grains on some specimens means shell structures are poorly preserved. Small shelly fossils extracted from glauconite bioclastic wackestone-grainstones are the best preserved, in regard to shell microstructure, and diversity is highest in these layers. These results suggest that limestones with authigenic glauconites could possibly be a good indicator for well-preserved small shelly fossils and that preservation potential of small shelly fossils is likely linked to differences between microfacies in early to middle Cambrian, North China.
Exploring Nocturnal Canopy Advection in Complex Terrain Through Active Heating Fiber Optics: Unraveling Temperature Dynamics and Airflow Patterns
Authors: Li Yi Fan , Ma Kuo Fong , Lin Chin Jen , Lai Yen Jen , Lin Po Hsiung , Nakai Taro
Published: March 2024

Nocturnal advection significantly influences the accurate estimation of net ecosystem exchange (NEE). This phenomenon is prevalent in Taiwan's subtropical montane forests, introducing a potential bias when relying solely on eddy covariance data for carbon budget calculations. From the preliminary analysis, the wind speed can be well estimated through the temperature difference between the heated and unheated fiber optical.The derived five-minute average wind speed exhibits a high coefficient of determination (R^2) of up to 0.94.In the current study, a fiber observational setup consisting of a 40m vertical section and a 90m horizontal section has been implemented to investigate temperature dynamics and airflow in complex terrain. The wind speed profile can be well reflected from the preliminary data analysis. Insights gained through this approach contribute to a better understanding of the nocturnal canopy advection model, offering valuable corrections to NEE estimates.
Transient calibration of the Amundsen Sea Embayment: a model and methodology comparison
Authors: Goldberg Daniel , Mathieu Morlighem
Published: March 2024

It is important that modellers be able to make reasonable projections of ice-sheet loss over the next 50-100 years so that costal planners can make informed decisions. Despite many innovations in modelling and satellite observing, several recent studies show that the agreement between models and the observational record remains poor -- raising concerns about their ability to predict responses to changes in climate on decadal to centennial time scales. A common means to address model-data misfit is via assimilation of satellite data, in which poorly constrained parameters are chosen in a way to minimize this misfit. Data assimilation has been employed extensively, including by many of the models participating in the ISMIP6 intercomparison. However, they are limited to observations at a single point in time (a "snapshot"). Such inversions do not take advantage of the time series of velocity and altimetry observations currently available -- largely due to the complexity and computational expense. The use of Automatic Differentiation makes such approaches possible. The method -- termed "transient assimilation" or "transient calibration" -- provides a physically consistent, time-dependent model which agrees with time-resolved observations.But with such a development, questions arise: how does transient calibration impact future modelled behaviour? Which types of observations most strongly constrain models? Are results consistent across different models? Here we apply transient calibration to the Amundsen Sea Embayment using two independent models, the Ice-sheet and Sea-level System Model (ISSM) and the MITgcm STREAMICE model, using time-resolved velocities and surface altimetry from 2004 to 2017. We assess the performance of transient compared to snapshot calibrations in terms of capturing past and current trends in speed change, thinning, and grounded ice loss; and we additionally run 50-year projections using the calibrated models. While overall 50-year mass loss is not strongly dependent on assimilation strategy, the rates of mass loss vary greatly, suggesting greater differences on the century time scale or longer. Moreover, we see that the runs calibrated with altimetry: (i) agree best with recent mass loss rates; (ii) show the greatest conformity between models; and (iii) show the largest mass loss rates at the end of the 50-year runs. The results likely have implications for optimal data needs and assimilation strategies in the next generation of ice-sheet models.
Advection Effect and Boundary Condition in the Formulation of Generalized Complementary Relationship for Evapotranspiration
Authors: Liu Wenzhao , Mu Zhaotao , Cheng Changwu
Published: March 2024

Land-surface evapotranspiration (ET) is a major component of the hydrologic cycle. It is a very attractive approach to estimate land surface ET by means of complementary relationship (CR). After 60 years of continuous exploration, the CR has developed from linear relationships to the present nonlinear ones. There are usually four boundary conditions (BCs) for the nonlinear CR, among which the first-order one in completely wet environments (dy/dxx=1) has been a debatable issue, including both the difference in values of dy/dxx=1, and the divergence in definitions of the independent variable x. It has always been a problem how to consider the advection effect in CR. The effect degree of advection from outside the region varies in the ET process at different spatial scales. In this paper, x denotes the ratio of equilibrium ET (ETe) to apparent potential ET (ETpa), y denotes the ratio of ET to ETpa, and x=1 is set as the benchmark with ETe as the lower limit of ETpa. According to the characteristics of ET processes at different spatial scales, we extend the value range of dy/dxx=1, and take dy/dxx=1=k (k≥0) to establish the generalized BC. The generalized CR model for ET is then proposed by using an exponential function, expressed as y=EXP[k/d(1-1/x^d)] (denoted by GCR-EXP; d>0), where k and d are model parameters. k is equal to 2 in the absence of advection, which is the most complementary case. When k < 2, warm advection plays a role, and the value of k gradually decreases as the advection influence increases. Brutsaert (2015) considered the effect of minimal advection, and used the potential ET (Priestley and Taylor,1972) as ET’s constraint to determine the first-order BC in completely wet environments for the polynomial model of CR, which is a case that fits quite well with a large number of observed data. When k = 0, the CR is no longer valid, and the ET is always equal to ETpa, which reflects the ET of a small wet surface. When 0≤x≤xmin, y is equal or approximately equal to 0. xmin and Priestley-Taylor coefficient α can be determined by the values of x at y close to 0 and to 1 in GCR-EXP model, respectively. For instance, the value of x at y=0.001 can be taken as the value of xmin. k reflects advection effects and the corresponding degrees of CR. Moreover, the GCR models, which satisfy the four BCs including dy/dxx=1=k, can be also expressed as a power-exponential function form and other ones besides the proposed exponential one (Supported by Project 41971049 of NSFC).
Destabilization of carbon in tropical peatlands by enhanced rock weathering
Authors: Klemme Alexandra , Rixen Tim , Müller Moritz , Notholt Justus , Warneke Thorsten
Published: March 2024

Southeast Asian peatlands represent a globally significant carbon store. Recent land use changes destabilize the peat, causing increased leaching of peat carbon into rivers. Despite resulting high river organic carbon concentrations, field data suggests only moderate carbon dioxide (CO2) emissions from rivers. We offer an explanation for this phenomenon by showing that carbon decomposition is hampered by the low pH in peat-draining rivers, and we find that enhanced input of carbonate minerals increases CO2 emissions by counteracting this pH limitation. One potential source of carbonate minerals to rivers is the application of enhanced weathering, a CO2 removal strategy that accelerates weathering-induced CO2 uptake from the atmosphere via the dispersion of rock powder. The effect of enhanced weathering on peatland carbon stocks is poorly understood. We present estimates for the response of CO2 emissions from tropical peat soils, rivers and coastal waters to enhanced weathering induced changes in soil acidity. The potential carbon uptake associated with enhanced weathering is reduced by 18−60 % by land-based re-emission of CO2 and is potentially offset completely by emissions from coastal waters. These findings suggest that, in contrast to the desired impact, enhanced weathering may destabilize the natural carbon cycle in tropical peatlands.
Ice dynamics and structural evolution of Jutulstraumen, Queen Maud Land, East Antarctica (1963 – 2022)
Authors: Sharma Anwesha , Stokes Chris R. , Jamieson Stewart S.R.
Published: March 2024

Jutulstraumen, a major outlet glacier in East Antarctica, drains into the Fimbulisen (∼39,400 km2). Here, we produce the first long term (~ 60 years) record of its behaviour using optical satellite imagery to map changes in its frontal position between 1963 and 2022, together with more recent datasets of ice velocity, surface elevation changes and grounding line position. Our analysis reveals that the ice front has been steadily advancing since its last major calving event in 1967, with a consistent ice flow velocity of ~ 720 ± 20 m yr-1(2000-2022). This has been accompanied by spatially variable ice surface thickening at an average rate of +0.15 ± 0.02 m yr-1 (2003-2020) between 20 km and 120 km inland of the grounding line. We also find evidence to suggest a minor grounding line advance of ~ 200 m (~ 6 m yr- 1) between 1990 and 2022, albeit with large uncertainties. Mapping of the major rifts on Jutulstraumen’s ice tongue from 2003 to 2022 (MODIS) reveals an overall increase in their lengths on both sides of the floating ice tongue, accompanied by some minor calving events. Given present-day ice front advance rates (~ 755 m yr-1), it would take around 31 years for the ice tongue to reach its most recent maximum extent in the mid 1960s, but extrapolation of rift lengthening suggests the next major calving event could take place sooner, possibly as early as the 2040s. Overall, however, there is no evidence of any dynamic imbalance, with ice-tongue advance, inland thickening and grounding line advance mirroring other major glaciers in Dronning Maud Land.
Towards a GEodesy and Time Reference In Space (GETRIS): A simulation study
Authors: Marz Stefan , Schlicht Anja , Hugentobler Urs
Published: March 2024

Progress in precise satellite orbit determination (POD) and navigation depends on the future ranging and time transfer capabilities. This leads to the need for high-precision links as well as high-precision clocks. However, not only a higher accuracy is required, but also the use of combination of complementary observation techniques to reduce systematic errors within an observation network. In a simulation study, we show our first concept of a GEodesy and Time Reference In Space (GETRIS). The initial GETRIS concept is based on the idea to have the reference in space build on geosynchronous orbit (GSO) satellites, but using Medium Earth Orbit (MEO) satellites is also possible. The goal is to achieve orbit accuracies of the GETRIS satellites at the same level as for ground stations – a few millimeters. Using high-precision optical links, the GETRIS shall establish connections to satellites in the near Earth environment and in deep space. When creating our GETRIS concept, we focus on three key pillars of a simulation study: Instrumentation, geometry and modelling. In terms of instrumentation, we performed scenarios using the synergy between L-band observations as well as high-precision dual one-way Optical Inter-Satellite Links (OISL) and ground-space based dual one-way links, called Optical Two-Way Links (OTWL), in different combinations. The geometry changes depending on the used observations network and the satellite constellation. Thereby, we analyze scenarios using a MEO-only and MEO+GSO constellations. To finally achieve mm-level orbit accuracies, an advanced modelling of non-gravitational forces is essential. A GETRIS can not only help with the connection of near Earth and deep space satellites, but also support the Global Geodetic Observing System (GGOS) and satellite missions such as GENESIS, which aim to realize a precise terrestrial reference frame with 1 mm accuracy and a stability of 0.1 mm/year.
Nucleation of jet engine oil vapours is a large source of aviation-related ultraﬁne particles
Authors: Ungeheuer Florian , Caudillo Lucía , Ditas Florian , Simon Mario , van Pinxteren Dominik , Kilic Dogushan , Rose Diana , Jacobi Stefan , Kürten Andreas , Curtius Joachim , Vogel Alexander L.
Published: March 2024

Various studies identified airports as a major source of ultrafine particles (UFPs – aerodynamic diameter
Eggs and sausages: wireless instrumentation for measuring ice anisotropy and kinematics
Authors: Craw Lisa , Prior-Jones Michael , Rathmann Nicolas , Hawkins Jonathan , Dow Christine , Bagshaw Elizabeth
Published: March 2024

Field observations of ice flow properties on large temporal and spatial scales are vital to improve our understanding of ice sheet and glacier dynamics. However, we are currently limited in what we can observe, and on what timescales, with wired instrumentation and remote sensing. We present preliminary tests of wireless instrumentation to measure the kinematics and anisotropy of flowing ice.We used a spherical probe ("cryoegg") emitting VHF radio waves to measure birefringence in 19 azimuthal directions around a borehole in the Northeast Greenland Ice Stream (NEGIS). From these data we are able to infer information about crystal anisotropy in the ice in three dimensions, and compare with a transfer matrix radio propagation model. This is a significant improvement on previous monostatic radar methods, which are limited to observations of crystal orientations in the horizontal plane.Additionally, we present initial observations of borehole tilt, temperature, pressure and conductivity from Donjek Glacier, Canada, collected using wireless borehole instruments ("cryowursts''). These data were transmitted through up to 170m of ice, and received at a solar-powered and satellite-enabled receiving station on the glacier surface. There is potential for these instruments to transmit data continuously from surging glaciers over multiple years.These preliminary studies demonstrate new possibilities for collecting exciting long-term datasets for glaciology.
Nitrogen modeling and performance of Multi-Soil-Layering (MSL)bioreactor treating domestic wastewater in rural community
Authors: Sbahi Sofyan , Ouazzani Naaila , Hejjaj Abdessamed , Lahrouni Abderrahman , Mandi Laila
Published: March 2024

The multi-soil-layering (MSL) bioreactor has been considered in the latest research as aninnovative bioreactor for reducing the level of pollutants in wastewater. The efficiency of theMSL bioreactor towards nitrogen pollution is due to the mineralization of organic nitrogen inaerobic layers to ammonia, and reactivity of ammonia nitrogen with soil and gravel by itsadsorption into soil layers followed by nitrification and denitrification processes when thealternating phases of oxygenated/anoxic conditions occurs in the filter. In this study, we haveexamined the performance of the MSL bioreactor at different hydraulic loading rates (HLRs)and predicted the removal rate of nitrogen. To improve the prediction accuracy of the models,the feature selection technique was performed before conducting the Neural Network model.The results showed a significant removal (p 0.93) and could help toinvestigate the MSL behavior.
Grazing dominantly regulates top soil organic carbon and nitrogen stocks in grasslands
Authors: Kepp Julia , Dannenmann Michael , Kiese Ralf , Pacay Narda , Schulz Stefanie , Schweizer Steffen , Schloter Michael , Schwärzler Theresa
Published: March 2024

For the past 17 years the Biodiversity Exploratories (BEs) in Germany have collected detailed data on land use intensity (LUI), climate as well as plant and microbial biodiversity for over 100 grassland sites in three different exploratories across Germany. Since these factors alongside physicochemical processes interactively drive soil nitrogen (SON) and carbon (SOC) cycling and storage, the BEs offer a unique opportunity to gain a mechanistic, process-based understanding of the interactions between soil type, climate, biodiversity and management that drive N and C turnover and storage in grasslands.We quantified SON and SOC stocks as well as δ15N and δ13C isotopic signatures for 25 grassland plots in each of the three exploratories, thereby covering a wide range of LUI. Currently, the results for the Schwäbische Alb exploratory are available. These data clearly show the importance to distinguish for the individual effects of LUI components (fertilization, mowing and grazing). For example, SOC and TN concentrations and stocks in the top 30 cm of soil tend to increase with LUI, but this increase is largely driven by the individual effect of the grazing component of LUI. The C:N ratio on the other hand was largely impacted by mowing and fertilization, possibly because mowing was a relatively important C loss pathway while fertilization was relatively important for N inputs. The narrower C:N ratio with increasing LUI negatively affected plant biodiversity.Both δ15N and δ13C were related largely to the overall LUI and plant biodiversity. Topsoil δ15N increased with higher LUI and lower plant biodiversity, likely due to the high δ15N of added organic fertilizer and reduced importance of biological N fixation with its low δ15N signature.Currently, our results indicate that grazing is the dominating management factor regulating SON and SOC stocks in calcareous grasslands of Southwest Germany, with grazing increasing SOC and SON stocks and associated soil functions. Further measurements and data evaluation will show whether this finding is of more universal importance for grasslands across Germany.
A Lagrangian investigation of the (micro)physical processes controlling warm conveyor belt moisture transport and cloud properties
Authors: Schwenk Cornelis , Miltenberger Annette
Published: March 2024

Warm conveyor belts (WCB) are regions of large-scale coherent airflow within extratropical cyclones that rapidly ascend from the boundary layer to the upper troposphere. During their ascent, WCB air parcels experience various microphysical processes that produce mixed-phase clouds and large amounts of precipitation. They also transport water vapour and cloud condensate to the upper troposphere/lower stratosphere (UTLS), which is important for Earth’s radiative budget. Recent studies have found that deep and embedded convection play an important role in WCBs. This points to the necessity of high-resolution simulations, that are well validated with observational data to provide a “benchmark” for coarser-resolution global (climate) models. We conduct a Lagrangian investigation of the physical processes governing WCB moisture transport and cloud composition with a particular focus on (i) the microphysical processes controlling moisture loss from the WCB, and (ii) the cloud microphysical properties of the cirrus clouds in the WCB outflow.To this end we conducted a case-study from the HALO-WISE campaign and ran a high-resolution doubly nested ICON simulation with a maximum (convection permitting) resolution of ~3km. Online trajectories are calculated that capture convective ascent and allow for a Lagrangian analysis of WCB moisture transport and WCB cloud structure.The Lagrangian metrics show large differences in the behaviour of moisture transport to the UTLS for trajectories with different ascent timescales. Fast ascending trajectories ascend further south and to much lower pressures and temperatures than their slower counterparts. They also produce much more precipitation and have markedly different hydrometeor contents throughout the ascent. In the ice phase, slow ascending trajectories mainly produce ice and snow through depositional growth, whereas fast trajectories also produce graupel and hail by collision-coalescence. Warm rain processes dominate the moisture loss for all ascent timescales, but for fast ascending trajectories the conversion of moisture to precipitation by microphysical processes in the ice phase increases. These findings are important because widely used coarse-resolution simulations with convection parameterization run the risk of missing the physical processes we see for the fastest ascending trajectories.
Towards a Semi-Analytical Model of the Long-Term Variations of the Heliospheric Structures
Authors: La Vacca Giuseppe , Della Torre Stefano , Gervasi Massimo
Published: March 2024

When developing a model to accurately predict the solar modulation of galactic cosmic rays, it is crucial to consider the global characteristics of the heliosphere. The dynamics and variability of the boundaries of the heliosphere have a significant impact on the long-term variation of cosmic rays, even at Earth's location. Therefore, it is highly desirable to have a global, time-dependent, and user-friendly heliospheric structure modelization. With this aim, we developed a semi-analytical, data-driven model that uses a simplified approach for solving the solar wind dynamics through the heliosphere, including the effect of the pick-up ions on the termination shock. The model also uses measurements of the energetic neutral atoms' spectra at 1AU to determine the distance of the heliopause. The model's predictions have been compared with the observations of the Voyager probes.
Long-term monitoring of methane emission rates from a biogas plant in Heidelberg, Germany: quantification of method uncertainties with controlled release experiments
Authors: Wietzel Julia , Korben Piotr , Hoheisel Antje , Kammerer Johannes , Schmidt Martina
Published: March 2024

The increasing number of biogas plants in Germany and Europe requires an appropriate strategy to quantify potential methane losses from biogas plants to ensure the sustainability of this renewable energy production. In addition to the large uncertainties in these emission factors, there is little information on the temporal variations of CH4 emissions from biogas plants.A long-term study of CH4 emission rates from a biogas plant in Heidelberg, Germany,  was performed over a five year period from August 2018 to December 2023. For a total of 27 measurement days the CH4 emission rates were determined for this biogas plant. These measurements were performed at different distances, weather conditions and two measurement devices. By averaging the individual emission rates of each measurement day at the biogas plant, an emission rate of 6.7 ± 0.8 kg CH4 h-1 was determined. For the calculation of CH4 emission rates, mobile measurements were performed nearby the biogas plant and analysed by applying a basic Gaussian plume dispersion model. Several controlled CH4 release experiments were carried out to analyse the accuracy and uncertainty of the CH4 emission rates from biogas plants and to improve the method. This included mobile measurements of methane concentration, meteorological measurements and the application of a Gaussian plume model. For this purpose, methane was released from gas cylinders in Heidelberg/Mannheim (Germany) in a controlled manner. Release rates between 0.1 and 0.7 kg CH4 h-1 were set and distances of 5 to 260 m between release point and inlet were investigated. The results obtained by applying a Gaussian plume model were compared with the actual release rates and thus the uncertainty of the method was analyzed in detail. The parameterization of the dispersion coefficients, the stability classes and thus the meteorological conditions during the measurements and other parameters like number of transects driven and averaging methods were assessed.
The role of hydration-induced processes in the deformation of the North China craton
Authors: Ballı Çetiner Açelya , Göğüş Oğuz , van Hunen Jeroen , Şengül Uluocak Ebru
Published: March 2024

Numerous previous studies have been conducted in the North China Craton to investigate its anomalously thin lithosphere, high magmatism, and extensional tectonics along its eastern margin. Based on petrological analyses it has been suggested that the cratonic mantle lost its root (~100 km) with multiple tectonic processes during the late Jurassic – Early Cretaceous. The weakening and erosion of the North China craton is often attributed to its high water content and lower viscosity of the lithosphere associated with the movement and position of the Paleo-Pacific plate. However, other mechanisms and control parameters for the craton destruction have been proposed, and the thinning of the North China craton remains an enigmatic process.To have a better understanding of the dynamics of the lithospheric deformations beneath the North China Craton that changes over time, we conducted a series of 2D geodynamic models. Specifically, we investigate the impact of hydration-induced processes on the lithosphere and the overriding plate and focus on parameters such as external tectonic forcing, the rheology and the strength of the overriding plate. Moreover, the effect of the angular position of the oceanic plate, and the existence of the mid-lithosphere discontinuities was also examined. Our results reveal that the destruction of North China Craton is more complex and heterogeneous than is often assumed in modelling studies. Furthermore, we find that without significant weakening, the mantle lithosphere is unlikely to delaminate. Extensive hydrous weakening may account for this, but external tectonic forcing in combination with non-linear rheology and eclogitization of the lower crust may have played an important role too.  
Mud volcanism and mud breccia clasts: how did they reach the surface?
Authors: Vivier Marlysa , Wang Hongliang , Yarushina Viktoriya , Mazzini Adriano
Published: March 2024

Mud volcanism is a geological phenomenon broadly diffused in active and passive tectonic settings and it is typically associated with petroleum systems. The mechanisms driving this process are the overpressure resulting from the generation of hydrocarbons at depth combined with the gravitative instability (e.g., shale buoyancy and density inversion) of the more buoyant rapidly buried sediments.Mud volcanoes experience episodic short-lived eruptive events during which the overpressured fluids and sediments are burst at the surface featuring spectacular explosive events. The erupted material is termed “mud breccia” and represents a mixture of all the lithologies that are intersected by the mud volcano conduit. The overpressured fluids driving the growing diapir promote the grinding and fracturing of the buried sedimentary formations throughout the conduit. As a result, the erupted mud breccia is a mixture of fine-grained sediments (i.e. matrix=clay, silt and sand) and larger clasts. Clasts can vary in size from few centimetres up to several cubic meters. So far it remained unclear how large clasts can travel from sedimentary sequences buried at several kilometers depth.Here we present some numerical modelling experiments to simulate the rise of large blocks moving from the roots of the mud volcano feeder channel and ultimately reaching the surface during the powerful eruptions.First, we study the slow rise of large clasts within the growing diapir of buoyancy sediment in the deep part of the mud volcano conduit. The geodynamical two-phase (solid + fluid) flow equations of mass balance, force balance and Darcy’s law are solved with Pseudo-transient method. The preliminary results shows that long distance (e.g. several km) transport of clasts within the diapir is possible, under the driven force provided by the buoyancy of the sediment and the upward fluid flow. The actual rise speed is dependent on the viscosity and the permeability of the solid matrix.Second, we apply a Verlet method model to simulate the eruption phase. We assume that the eruptive events occur when at shallow depth within the conduit is reached an overpressure sufficient to overcome the overburden lithospheric pressure. When these conditions occur, and when the overpressured fluids are expelled at the surface, the fluidization of the sediments is triggered, and large clasts may be transposrted to their final destination at the surface. Preliminary results reveal that during this process large clasts can be transported. This method focuses on the movement of the clasts themselves. The viscosity of the surrounding fluids is taken into account with a linear drag force. Nevertheless, a method considering the movement of the surrounding fluids could be a possible improvement.
Overview of how subsurface carbon dioxide promotes geothermal energy extraction
Authors: Saar Martin O.
Published: March 2024

The properties of carbon dioxide (CO2) under deep geologic conditions make it an excellent subsurface working fluid in geothermal systems, including CO2-Plume Geothermal (CPG) systems, Enhanced Geothermal Systems (EGS), and deep closed-loop Advanced Geothermal Systems (AGS). Supercritical CO2’s low viscosity, high density, and high thermal expansion coefficient render CO2 a highly efficient energy transfer, extraction, and storage fluid. These properties typically overcompensate the lower specific heat capacity of CO2, compared to brine, which is the conventional working fluid underground. Furthermore, CO2 can also reduce fluid-mineral reactions, such as mineral precipitation, which often clog reservoirs, wells, and equipment. Applying geothermal energy extraction to CO2 Capture and Sequestration (CCS) in deeper reservoirs results in true CO2 Capture Utilization and Sequestration (CCUS), enabling these projects to ultimately sequester all initially injected CO2 underground at reduced cost. In this presentation, I give an overview of how CO2 can be used to efficiently produce geothermal energy, store surface-generated energy underground, and/or support CCS operations to promote energy security while combating climate change.
Unraveling rapid exhumation: Insights into the increase of exhumation rates in the Sutlej River anticline (NW Indian Himalaya) over the last 200 kyr.
Authors: Genge Marie , Bouscary Chloé , Webb Alex , King Georgina , Adeoti Blessing , Ganbat Ari , Vlaha Dominik
Published: March 2024

Estimating exhumation rates on Pleistocene-Holocene time scales presents a challenge due to the scarcity of suitable low-temperature thermochronometers. Apatite helium (AHe) dating is unable to precisely differentiate cooling ages
Evaluating ICON-ART-LAM vertical profiles and columns of CH4 for May-June 2018 over Europe
Authors: Blechschmidt Anne-Marlene , Mamtimin Buhalqem , Rösch Thomas , Kaiser-Weiss Andrea
Published: March 2024

A greenhouse gas satellite data assimilation system is currently being developed for the ICOsahedral Nonhydrostatic (ICON) - Aerosols and Reactive Trace gases (ART) - Limited Area Mode (LAM) model at the German Weather Service. This work is part of the modelling module of the Integrated Greenhouse Gas Monitoring System project (ITMS-M). A first step towards the satellite data assimilation system is the derivation of vertical columns of methane from ICON-ART-LAM simulations that can be compared to column retrievals of CH4 from satellite sensors such as the TROPOspheric Monitoring Instrument (TROPOMI) on board of the Copernicus Sentinel-5 Precursor satellite. As the ICON-ART-LAM simulations are limited to about 20 km altitude, vertical columns cannot directly be derived from the model output alone.In this presentation, the potential of adding CH4 concentrations from the Copernicus Atmosphere Monitoring Service (CAMS) egg4 greenhouse gas reanalysis and CAMS inversion optimized products above the ICON-ART-LAM upper boundary is evaluated for the time period May-June 2018 and a domain covering Europe (6.5 x 6.5 km2 horizontal grid spacing). The vertical profiles of ICON-ART-LAM are investigated for consistency with the CAMS simulations and ICON-ART-LAM vertical columns derived from the model output will be compared against CH4 vertical columns from TROPOMI. For the latter, the satellite orbit and the sensitivity of the satellite sensor towards retrieving CH4 in different layers of the atmosphere are considered.
‘Almost Surely’ – Exploring the potential of (video) art to communicate probabilities and climate risk
Authors: Layritz Lucia Sophie
Published: March 2024

Humans often struggle to intuitively grasp probabilities, which challenges the effective communication of climate risk. Here, I want to explore the potential of (video) art to intuitively translate probability and other abstract mathematical concepts in the context of climate change.Created as part of an interdisciplinary university course on Ecological Aesthetics, ‘Almost Surely’ is a video art piece bridging the probabilistic nature of scientific climate projections with their factual manifestation in the real world. The piece contrasts the technical language of statistics-based knowledge generation used by reports of the Intergovernmental Panel on Climate Change (IPCC) with scenes of nature and everyday life, where probabilities are translated into reality. In line with my Ph.D. research and the local context of making this piece in California, I focused on the impact of wildfire on familiar terrestrial landscapes such as Joshua Tree or Big Basin National Park.I aim to reflect on my experience creating this film, navigating the intersection of art, art discourse, and science as a climate scientist, and discuss some of the challenges and questions I came across when translating precise scientific concepts into intuitively felt visuals and storylines.
Modelling the evolution of the weathering crust
Authors: Woods Tilly , Hewitt Ian
Published: March 2024

The weathering crust is a porous layer of ice found at an ice sheet surface, formed by shortwave radiation penetrating below the surface and causing internal melting. It is a dynamic hydrological system that acts to transport meltwater, impurities, and microbes across the ice sheet surface into larger-scale hydrological features such as surface streams. The weathering crust is very variable, growing and decaying on the order of hours and days in response to changing weather conditions, with consequences for the surface albedo as well as meltwater storage and transport. The albedo is impacted both by the weathering crust structure and the presence of microbes and impurities (for example in the south-western Greenland ‘dark zone’). We have developed two mathematical models to investigate the evolution of the weathering crust and microbes over space and time: a one-dimensional model for the vertical structure, and a depth-integrated model to explore the lateral extent of the weathering crust and transport of meltwater. We present solutions generated by idealised forcings as well as observations from the field. This explains the observed response of the weathering crust to short-term changes in weather, and provides insight into the longer-term response of the weathering crust and algal blooms to climate change.
Using sediment texture and geochemistry as predictors to automatically classify sub-depositional environments in a modern estuary
Authors: Nichols Thomas E , Houghton James E , Worden Richard H , Duller Robert A , Griffiths Joshua , Utley James E P
Published: March 2024

Sedimentary cores from the Ravenglass Estuary, NW England, lack some of the sedimentary structures which can be seen in other estuarine sands due to their unconsolidated nature, making it difficult to meaningfully interpret depositional environments using standard sedimentological facies analysis. Here we explore how sediment texture, obtained from laser particle size analysis, and bulk geochemistry, obtained from portable X-ray fluorescence, can be used independently, or in combination, within a machine learning model to automatically classify sub-depositional environment and estuarine zone at the estuary surface to create a model which can be used to classify subsurface sediment samples. Using an adapted an established machine learning workflow we select the most informative geochemical elements to be included in the training set for the classification model.The most important geochemical elements for modelling represent major elements of the most abundant minerals in the estuary, and minor elements representing trace signals of sulfide mineral deposits present in the hinterland. Models that are trained exclusively on textural data significantly outperform those that use geochemical data when classifying sub-depositional environment but are comparable when classifying estuarine zone. However, the combination of textural and geochemical data in training sets improves model performance in all but one class when compared to separate textural and geochemical models.Ultimately, we have applied the surface-calibrated combined textural and geochemical model to classify paleo-sub-depositional environment in geotechnical cores obtained from the Ravenglass Estuary. This allows us to interpret their environmental evolution and build scaled correlation panels spanning key areas of the estuary to suggest how the estuary has changed since its formation.
Wave-current interactions in a high-flow tidal channel
Authors: Guerra Maricarmen , Hay Alex E , Sagredo Nicolás , Acuña Aaron
Published: March 2024

High-flow tidal channels (Re~O(108)) are characterized by strong bidirectional currents (3 m/s) and high turbulence intensities. As in most coastal environments, these strong flows are affected by wind and waves, especially during severe weather events. The combined occurrence of strong currents and wind-generated surface gravity waves is a nonlinear coupled process in which both the currents and the incident wave field are modified. In this work, the evolution of mean wave parameters in a high-flow tidal channel is evaluated for various wave and tidal flow conditions. Synchronous current, turbulence, and surface altimeter data measured by a bottom-mounted acoustic Doppler current profiler (ADCP) deployed in Grand Passage, a tidal channel within the Bay of Fundy in eastern Canada, are analyzed. Results indicate that wave growth and wave propagation are coupled with the magnitude and relative direction of the current. During each measured high-wind event, the significant wave height consistently increased, and the wavelength decreased, as the current magnitude increased when locally generated waves opposed the currents. To the contrary, the significant wave height was drastically reduced when the waves follow the currents even for a small current magnitude. In addition, elevated turbulence kinetic energy and vertical plumes of elevated acoustic backscatter amplitude were observed in the upper water column during high-wind events, likely bubbles injected into the free surface by breaking waves (whitecaps) and transported through the water column by the turbulence generated by tidal currents. Obtained results allow to identify when and where wave-current interactions are significant, what their implications are for the complex dynamics of tidal channels, and suggest that currents must be incorporated into forecast wave models to improve local sea state predictions and consequently navigation safety. 
Computationally efficient evaluation of Earth System Models in the presence of complex uncertainties
Authors: Weitzel Nils , Racky Muriel , Braschoß Laura , Rehfeld Kira
Published: March 2024

Comparing Earth System Model (ESM) simulations with in-situ, lab, and remote sensing measurements often involves analytically intractable uncertainty structures for example due to observational uncertainties, internal variability in the climate system, and limitations of ESMs. With increasing resolution of models, ensemble sizes, length of simulations, and number of observations, this can create computational bottlenecks. Making use of Monte Carlo techniques in a data cube architecture, we present a python package for efficient propagation of complex uncertainties in model-data comparison. Additionally, the package contains functionalities for visualizations of uncertainties and the computation of probabilistic score functions.Our focus is on measurement operators, in particular so-called proxy system models that map ESM output onto proxy measurements for transient paleoclimate simulations. Proxy system models contain multiple sources of autocorrelated and non-Gaussian uncertainties due to complex proxy-climate relationships, chronological uncertainties, and processes perturbing the recorded climate signal during the sedimentation of the proxy. Thereby, we connect data cube methods for processing climate simulations with analysis techniques for point data such as those stemming from time series of paleoclimate proxy records. We demonstrate our approach by quantifying the discrepancies of temperature and forest cover changes between global proxy networks and transient simulations from the Last Glacial Maximum to present-day. Given the ongoing shift in the paleoclimate modelling community from equilibrium time-slice towards long transient simulations, our work can help integrate the evaluation of simulations from the Paleoclimate Modelling Intercomparison Project (PMIP) into CMIP7 model benchmarking. Additionally, the implemented methods are transferable to other types of observations that are subject to analytically intractable uncertainty structures.
Active Fault and Paleoseismological studies in the hinterland region of NW Himalaya
Authors: Husain Rukhshar , Malik Javed N
Published: March 2024

The Indian plate is currently underthrusting beneath the Tibetan plateau along the Main Himalayan Thrust (MHT). The strain is getting accumulated during the inter-seismic period on MHT due to this ongoing convergence. The accumulated strain energy is released in a stick-slip fashion on MHT causing destructive earthquakes. Several strong earthquakes within the Himalayan zone have been reported in previous studies such as 1897 at Shillong (Mw 8.2), 1905 at Kangra (Mw 7.8), 1934 at Bihar-Nepal (Mw 8.1), 1950 at Assam (Mw 8.4), 2005 at Muzaffarabad (Mw 7.6), 2015 at Gorkha (Mw 7.8), and 2015 in Afghanistan (Mw 7.6). Based on the distribution of recent and historic earthquake activity in the Himalayas, three seismic gaps can be distinguished from west to east: the Kashmir Seismic Gap (west of the 1905 Kangra earthquake), the Central Seismic Gap (between the 1905 and earthquakes), and the Assam Seismic Gap (between the 1897 and 1950 earthquakes). The major objective of this study is to investigate the hinterland region in the NW Himalaya, which is relatively less explored in terms of its Active Tectonics & Paleoseismology as compared to the deformation front along the Main Himalayan Thrust (MFT). The Nahan salient and Kangra re-entrant are characterised by a complicated pattern of fault distribution which has been proposed in previous studies to get activated, either individually or alongside the Main Frontal thrust, during past large to great-magnitude earthquakes. A detailed tectono-geomorphic map has been prepared using the Cartosat-1 dataset, and geomorphic markers suggestive of recent tectonic activity have been identified in the study region. An exhaustive fieldwork has been conducted, during which a total of 13 samples were collected for Optically Stimulated Luminescence (OSL) dating and Carbon dating to identify signatures of past earthquakes and assess the possibility and degree to which the 1905 earthquake has affected the region. Based on the detailed tectono-geomorphological and paleoseismological investigations, we will be able to assess regional seismic hazards.(*Author RH aka Rukhshar)
Higher global gross primary productivity under future climate with more advanced representations of photosynthesis
Authors: Cuntz Matthias , Knauer Jürgen , Smith Benjamin , Canadell Josep G. , Medlyn Belinda , Bennet Alison C , Caldararu Silvia , Haverd Vanessa
Published: March 2024

Gross primary productivity (GPP) is the key determinant of land carbon uptake, but its representation in terrestrial biosphere models (TBMs) does not reflect our latest physiological understanding. We implemented three empirically well supported but often omitted mechanisms into the TBM CABLE-POP: photosynthetic temperature acclimation, explicit mesophyll conductance, and photosynthetic optimization through redistribution of leaf nitrogen. We used the RCP8.5 climate scenario to conduct factorial model simulations characterizing the individual and combined effects of the three mechanisms on projections of GPP. Simulated global GPP increased more strongly (up to 20% by 2070–2099) in more comprehensive representations of photosynthesis compared to the model lacking the three mechanisms. The experiments revealed non-additive interactions among the mechanisms as combined effects were stronger than the sum of the individual effects. The modeled responses are explained by changes in the photosynthetic sensitivity to temperature and CO2 caused by the added mechanisms. Our results suggest that current TBMs underestimate GPP responses to future CO2 and climate conditions.