bluuebunny/crossref_metadata_2025 huggingface dataset:
Olivine exit interviews – gaining insights into magma assembly from olivine populations
Authors: Ruprecht Philipp
Published: March 2024

Most eruptions tap magmas from a range of pressures and storage environments within the crust and potentially even in the mantle. In this context, early crystallizing phases, such as olivine, provide a unique perspective into the deeper parts of many eruptions. When considering large olivine populations, compositional spectra of those populations serve as proxies for the different batches of magma that constitute the sometimes complex assembly of an eruption. While major element compositions in olivine provide links to melt compositions, minor and trace elements fingerprint deviations from simple liquid lines of descent. Moreover, Fe-Mg isotope signatures demonstrate whether magmas equilibrated diffusively or whether some mineral zoning retains growth histories prior and during assembly.To reveal the full picture of the assembly of an eruption and potentially changes during the eruption it is essential to collect olivine “interviews” from a large population as they exit the volcano. Here I show that such magma assembly prior to eruption varies greatly from one eruption to the next and that simple monogenetic cones may contain much more complex histories as they quickly pass the crust and may extract crystal cargo from a variety of locations and conditions, while many volumetrically larger more long-lived systems retain a simpler story despite their polybaric magma storage.
The cyclostratigraphy of the Late Triassic Qiangtang Basin in Tibet and the orbital forcing for the Carnian Pluvial Episode
Authors: Zhang Qian , Fu Xiugen , Wang Jian
Published: March 2024

The Qiangtang Basin, situated on the Tibetan Plateau, is a basin that contains hydrocarbons and has significant potential for hydrocarbon exploration. However, reconstructing sea-level changes and understanding the sedimentary evolution of the Qiangtang Basin has been hindered by the lack of robust high-resolution geochronology. Meanwhile, the Late Triassic stratigraphy of the Qiangtang Basin has also reported the Carnian pluvial episode, the driving mechanism of which is controversial. In this study, the cyclostratigraphy of the Late Triassic Boli La and Bagong Formations in the Qiangtang Basin was analyzed using high-resolution gamma-ray data. Time series analysis shows that there are 405 kyr eccentricity cycles in the gamma-ray data series. The gamma-ray series was tuned to 405 kyr. Then, we establish a floating astronomical timescale with a length of 17.04 Myr. This astronomical time scale establishes an anchored astronomical time scale using the age of the volcanic rocks found in the top of the Bagong Formation in the drill core as an anchor point. Using the anchored astronomical chronology, we reconstructed the Late Triassic sea level change in the Qiangtang Basin using a recently developed sediment noise model. The reconstructed sea level change is generally consistent with the global sea level curve. The antiphase relationship between the filtered long-term obliquity cycles and the sea-level curves reconstructed from the sedimentary noise model suggests that the long-term obliquity cycles may have been the main driver of the Late Triassic greenhouse sea-level change. Meanwhile, the modulation maxima of the long-term obliquity-modulated cycles correlate well with high sea level, episodic negative carbon isotope excursions, global warming, and marine biotic crises, suggesting that obliquity forcing may have played a prominent role during the Carnian Pluvial Episode. Our results suggest that orbital forcing enhanced the hydrological cycle during the Carnian Pluvial Episode. Our study provides a precise, high-resolution time scale for studying the sedimentary evolution of the Qiangtang Basin, as well as a broader perspective on the relationship between the Carnian Pluvial Episode and astronomical forcing.
Dwarf shrub δ18O from the Top of the World / Everest region record large-scale climate signals
Authors: Grießinger Jussi , Meier Wolfgang Jens-Henrik , Zhu Haifeng , Ru Huang , Liang Eryuan
Published: March 2024

Oxygen isotopes (δ18O) derived from tree-rings are an excellent and frequently utilized annually resolved climate proxy. Above the tree-line, woody (dwarf) shrubs can further densify the still fragmentary global paleoclimatic network, which is particularly relevant for the high altitudes of the Himalayan Arc. Still, few studies have investigated the suitability of δ18O from shrubs for climate reconstructions, specifically on the windward southern slopes of the Central Himalayan Arc. In this study, we evaluated the climate imprints on juniper dwarf shrubs located above 4,000 m asl in the Mount Everest region, Nepal. Three gridded climate data sets (CRU TS, ERA-5 and CHELSA) with a spatial resolution between 0.5° and 0.08° were used to evaluate the respective climate-proxy relationships. The strong influence of variations in temperatures and moisture (precipitation, rH, VPD) on our δ18O time series are most evident during the summer monsoon season. Spatial correlation analyses further confirm a strong supra-regional representativity of our proxy across large parts of the Himalaya and northern India. The dependency on large-scale atmospheric circulation is underlined by significant correlations between δ18O, various monsoon indices and more complex and coupled (tropical) ocean-atmospheric oscillation patterns such as the Southern Oscillation Index and the Madden-Julian Oscillation. By analyzing synoptic weather patterns of the Indian Subcontinent we can further demonstrate, that our δ18O series is strongly influenced by climate conditions during the break monsoon periods than to conditions during the active monsoon period. During the breaking periods, two weather patterns are predominantly influencing our δ18O series when i) air masses are increasingly originating from (North)West, leading to a sharp decrease in precipitation and higher temperatures or when ii) a shift of the monsoon trough towards the North results in a decrease of rainfall over the India subcontinent and an increase in precipitation over the Himalayan region.
Constraining the denitrification process in conventional and regenerative agriculture
Authors: Micucci Gianni , Sgouridis Fotis , Krause Stefan , Lynch Iseult , McNamara Niall P. , Roos Felicity , Jonathan Leake , Ullah Sami
Published: March 2024

In this study, we aimed to constrain and characterize the dynamics of denitrification in three different fields: one conventional arable and two types of pasture (“leys”). During a one-year field campaign, denitrification was measured using our newly developed method combining the application of 15N tracer and artificial atmosphere for the incubation of soil cores under field conditions (Micucci, 2022), while total N2O emissions were measured using static flux chambers during parallel incubations. Our objectives were to determine the best way to upscale soil core denitrification measurements and trace the fate of applied synthetic nitrogen fertilizer via denitrification in conventional agriculture in comparison to pastures under regenerative agriculture practices.We determined that the best way to derive field-scale fluxes of denitrification was to use the core method to calculate the source partitioning coefficient (SPC) and product ratio (PR) and use these metrics in combination with static chamber data. The SPC is defined as the proportion of total N2O emissions that originates from denitrification while the product ratio measures the proportion of denitrification product emitted as N2O rather than N2.During the field campaign, we estimated that 22 kgN ha-1 were lost via denitrification in the arable field, amongst which 15.17 were attributed to fertilizer application, representing around 8% of the 200 kgN ha-1 applied. Furthermore, 9 % of the denitrified fertilizer was emitted as N2O rather than N2. On the other hand, the unfertilized ley emitted only 2.6 kgN ha-1 via denitrification annually. Overall, the total N2O emissions in the fertilizer arable field were responsible for around 2 t eqCO2 ha-1 year-1 compared to 0.15 in the unfertilized ley, highlighting the importance of land management in strategies of greenhouse gas emission reduction.
Seismic Hazard in terms of Peak Ground Acceleration (PGA) for coast of Calicut, State of Kerala (INDIA)
Authors: Shanker Daya , Rafih AP Mohamed
Published: March 2024

Seismic hazard assessment involves quantitatively estimating ground shaking at site. There are two main approaches for estimating seismic hazard, Deterministic seismic hazard assessment (DSHA) and Probabilistic seismic hazard assessment (PSHA). In the present investigation DSHA is used, it relies on the worst-case scenario earthquake. The state of Kerala (9°N - 13°N and 75°E - 78°E) which lies in the seismic zone III, having a zone factor 0.16, has been considered to estimate seismic hazard in terms of PGA. Based on analyses of seismotectonics of the area, 26 seismogenic sources were identified and used for the PGA estimation. The peak horizontal accelerations (Ah) 0.2344g and peak vertical accelerations (Av) 0.1395g were computed for the city of Calicut. For other cities, Thiruvananthapuram, Kollam, Palakkad, Kochi, and Thrissur horizontal (Ah) and vertical accelerations (Av) were also estimated. However, the highest value was found to be at Calicut followed by Palakkad. In case of Palakkad, the values were influenced by cluster of faults located there while, at Calicut was caused by the Fault – 1 (source) which is in the Arabian Sea near the coast of the city. It has been observed that the seismic hazard assessment of Kerala advocate the PGA (Ah) falls in the range of 0.02g to 0.47g and PGA (Av) varies from 0.01g to 0.33g. These accelerations seem to be more realistic since they are based on consideration of many seismotectonic sources in the region that may rupture causing earthquakes. The ratio of Av/Ah was found to be in the range of 0.70 to 0.38. The prepared contour maps for the region show that larger peak ground accelerations are present in the region where there is a higher density of larger faults and vice versa. The findings highlight the need for further studies and enhanced preparedness measures in Kerala, aiming to mitigate potential seismic risks and ensure the safety of its residents in this seismically active region.
Ocean Alk-Align: an international research project to assess the potential of Ocean Alkalinity Enhancement for marine Carbon Dioxide Removal
Authors: Oberlander Jessica , Atamanchuk Dariia , Bach Lennart , Fennel Katja , Hartmann Jens , Keller David P. , Mihailova Boriana , Musgrave Ruth , Oschlies Andreas , Riebesell Ulf , Schulz Kai G. , Wallace Douglas
Published: March 2024

Of the various marine Carbon Dioxide Removal (CDR) technologies proposed to date, ocean alkalinity enhancement (OAE) has, arguably, the largest carbon removal potential. OAE has several advantages over other approaches: it does not compete for nutrient use, it is applicable to large regions of the coastal and open ocean, it can mitigate ocean acidification, and it has a high potential for permanence. Consequently, a growing number of private-sector innovators are actively pursuing OAE, leading to the potential risk that independent, non-profit-oriented research will fall behind in providing a balanced assessment of OAE.The Ocean Alk-Align project is a multi-year research effort involving an international consortium of researchers from Canada, Germany, and Australia. The project seeks to increase knowledge on three key research topics essential for OAE implementation: (1) efficiency and durability of CO2 removal; (2) environmental safety; (3) monitoring and verification. This will be done through the development and application of state-of-the-art experimental research, real-world observations, and near-field to Earth system modeling.The Ocean Alk-Align project will use a multi-scale combination of laboratory and field experimentation in addition to turbulent-, regional-, and large-scale modelling. This presentation will provide an overview of ongoing and planned activities as well as some early results.
Effects of Long-Term Wetland Variations on Flood Risks in the Yangtze River Basin 
Authors: Guo Ziying , Shi Xiaogang , Zhao Qunshan
Published: March 2024

In the Yangtze River Basin (YRB), flooding is the most frequent natural disaster with enormous socio-economic damages. As a critical component in the hydrological cycle, the wetlands along the YRB have been changing during recent decades because of urbanization, intensive farming (e.g., aquaculture and agriculture) and climate change. Due to the lack of a long-term wetland classification dataset with comprehensive wetland categories, however, there’s a noticeable gap in the YRB water management regarding the relative roles of different wetland categories on flood resilience. Therefore, this study aimed to generate a long-term wetland classification dataset for the YRB and further investigate the long-term wetland variations on the YRB flood risk assessments for the period from 1985 to 2021. The dataset named Long-Term Wetland Classification Dataset for YRB (LTWCD_YRB) was created using a Random Forest machine learning classifier on Google Earth Engine with 30m resolution Landsat 5, 7, 8 muti-spectral images. The maps of LTWCD_YRB demonstrated the spatial distribution, annual variability, and seasonal cycle of nine wetland categories in the extent, and the total validation accuracy can reach 85%. The LTWCD_YRB indicated that the total wetland area of the YRB in 2021 was larger than that in 1985, with constantly increased human-made wetlands and fluctuated natural wetlands. Aquaculture ponds expanded the most (4,987 km2); inland marsh in the source region was the wetland category with the most fluctuations. Seasonal changes in wetlands were prominent in the Poyang Lake Basin, Dongting Lake Basin, and YRB source region. The LTWCD_YRB can offer a consistent agreement of wetland area variations with the other satellite-based wetland datasets in the YRB, which is valuable for researchers and stakeholders to better understand the YRB wetlands and would support sustainable wetland management practices. With the LTWCD_YRB data as modelling inputs, a GIS-based spatial multi-index flooding risk assessment model was applied for investigating the long-term implications of wetland variations on flood risks in the YRB. The model results indicate that in the year with large floods and extremely high precipitation, flood risk level increased obviously after adding the wetland factor. For the years with normal precipitation, flood risk level decreased with wetlands expansion and increased with wetlands shrinkage in the YRB. The long-term expansion of aquaculture ponds contributed to a lower flood risk in the Taihu Lake Basin. In contrast, the Poyang Lake Basin experienced an increasing flood risk due to the long-term shrinkage in lake areas resulting from soil erosion and urbanization along the lakeside. This study would be helpful for stakeholders to develop feasible wetland management practices, and to improve flood risk resilience in the YRB.
Adaptive Strategies to Reconcile Diverse Equity Preferences in Climate Policies
Authors: Biswas Palok , Zatarain Salazar Jazmin , Kwakkel Jan
Published: March 2024

Normative uncertainty, which arises from diverse ethical perspectives and uncertainty about distributional outcomes, poses a significant hurdle in climate policy negotiations. Such uncertainty illustrates the core challenge of achieving agreement on the moral principles or equity considerations that should guide the development of climate policies.Integrated Assessment Models (IAMs), while influential in shaping decisions, fall short in factoring in this normative uncertainty in climate policies. To address this issue, we developed an IAM framework called JUSTICE. JUSTICE leverages the economic insights of the RICE50+ model to explicitly account for spatiotemporal heterogeneity alongside probabilistic forecasting of the FaIR climate model for a better representation of climate uncertainty. We also reformulate the Social Welfare Function (SWF) in light of four distributive justice principles - Utilitarian, Sufficientarian, Egalitarian, and Prioritarian - to encapsulate the ethical pluralism of different stakeholders. We search for adaptive mitigation policies by assimilating two established decision-making frameworks: Multi-Objective Robust Decision-Making (MORDM) and Evolutionary Multi-Objective Direct Policy Search (EMODPS). MORDM rigorously tests potential policies against deep uncertainties to find robust, Pareto-optimal choices. At the same time, EMODPS fine-tunes strategies to reconcile stakeholders' diverse objectives, ensuring policies are adaptive and robust. Our findings demonstrate that adaptive policies facilitate deliberation. They identify common ground among policymakers with diverse perspectives by being robust across multiple realizations of deep uncertainties and flexible enough to accommodate conflicting ethical perspectives. Our approach designs climate policies that are both inclusive and adaptive, ensuring they account for immediate necessities while remaining responsive to unfolding future challenges—thereby upholding the tenets of both intra and intergenerational justice.  In summary, our study underscores the pivotal role of normative clarity in facilitating stakeholder dialogue and ensuring that climate policies are scientifically sound and socially equitable. Incorporating diverse normative perspectives and acknowledging normative uncertainties, our adaptive strategies limit overconfidence in climate policies, promote inclusivity without subjecting individuals to undue risks, and redefine the application of IAMs in crafting fair and just climate policies. Keywords: Integrated Assessment Models, Climate policy, Distributive justice, Deep Uncertainty, Adaptive strategies, Social Welfare Function, Robust decision-making.
Mercury's crustal heterogeneity revealed by gravity data modelling 
Authors: Buoninfante Salvatore , Milano Maurizio , Negri Barbara , Plainaki Christina , Sindoni Giuseppe , Fedi Maurizio
Published: March 2024

The study of the internal structure of Mercury is fundamental for understanding the formation and evolution of the planet and of the entire Solar System. The main purpose of this work was the analysis of the MESS160A gravity field model [1] to show the presence of crustal heterogeneities in density. According to the flexural isostatic response curve, we noted that the lithospheric flexure occurs in the spherical harmonic degree range 5-80, consistently with a flexural compensation model, while for degrees lower than 5 the flexural rigidity tends to 0 and a local compensation model can be assumed. Removing spherical harmonic components up to degree 4, as they are associated with the polar mass deficit and to the morphological contrasts, we assumed a flexural compensation model [2] to first estimate a mean elastic thickness of 30 ± 10 km. We, then, modeled the lithospheric flexure regardless of the gravity field and calculated the isostatic gravity anomalies by subtracting the gravity effect caused by the isostatic compensation to Bouguer anomalies. In this way, we proved that considerable lateral density variations occur within the Mercury's crust [3]. We also estimated the curst-mante interface depth, varying from 19 to 42 km. Isostatic anomalies are mainly related to density variations in the crust: gravity highs mostly correspond to large-impact basins, suggesting intra-crustal magmatic intrusions as the main origin of these anomalies. Isostatic gravity lows prevail, instead, above intercrater plains and may represent the signature of a heavily fractured crust. Acknowledgements: We gratefully acknowledge funding from the Italian Space Agency (ASI) under ASI-INAF agreement 2017-47-H.0. References:[1] Konopliv, A. S. et al. (2020). Icarus, 335.[2] Turcotte, D. L. et al. (1981). J. Geophys. Res., 86.[3] Buoninfante, S. et al. (2023). Sci. Rep., 13.
Application of Dempster-Schafer theory for predicting ephemeral gullies with remote sensing data
Authors: Fathololoumi Solmaz , B. Vasava Hiteshkumar , Daggupati Prasad , Biswas Asim
Published: March 2024

Mapping Ephemeral Gullies (EGs) is essential for enhancing the management and conservation of natural and agricultural resources. This study aimed to devise a novel approach utilizing the Dempster-Shafer (D-S) theory to achieve more accurate EGs mapping. To accomplish this, a high-resolution satellite image and ground data collected during a field visit to the Niagara region in Canada were utilized. Firstly, spectral features that effectively identify EGs were extracted from the satellite imagery. Subsequently, three machine learning classifiers including the artificial neural network (ANN), support vector machine (SVM), and random forest (RF) were employed to generate the EGs map. Finally, the D-S theory was applied to integrate the outcomes from these classifiers, aiming for a more precise EGs map. The results highlighted that the most significant variable importance was attributed to the Normalized Near-Infrared (NIR) (18%) and Soil line (15%). The average producer and user accuracies for the EGs and non-EGs classes across the three classifiers were 0.53 and 0.67, and 0.97 and 0.95, respectively. Incorporating the D-S theory enhanced these accuracy values by 0.15 and 0.19 for EGs and 0.02 and 0.02 for non-EGs. Furthermore, the overall accuracies for the EGs maps generated by the ANN, SVM, RF, and D-S theory models were 94%, 93%, 95%, and 97%, respectively. The results of this study showed that D-S theory is useful for improving the EGs mapping using remote sensing data.
Initiation of the Seismic Network Expansion and Modernization in Ukraine
Authors: Farfuliak Liudmyla , Amashukeli Tetiana , Chiang Andrea , Mackey Kevin , Haniiev Oleksandr , Kuplovskyi Bohdan , Aderhold Kasey , Burk Daniel , Prokopyshyn Vasyl , Petrenko Kostiantyn
Published: March 2024

The seismic hazard department and department of the Carpathian region seismicity of the Subbotin Institute of Geophysics of the National Academy of Science of Ukraine, with the support and collaboration of the U.S. Department of Energy, Lawrence Livermore National Laboratory, Michigan State University, and the EarthScope Consortium had done first steps to expand the Ukrainian National Seismic Network (UT) through the installation of permanent broadband seismic stations in the territory of Ukraine.The main goal of the Seismic Network Expansion and Modernization in Ukraine is to improve regional network coverage by making high-quality data from new stations openly available to the global scientific community in real time. It will strengthen national seismic monitoring and earthquake response capabilities in Ukraine by upgrading and expanding the national networks with high-quality broadband seismometers and strong motion sensors. It will emphasize data quality, real-time data exchange, and network sustainability through training in best practices on station site selection, installation, data management, and network operation.To maximize the effectiveness of investigating existing and new seismic sites, multiple factors must be considered during the initial selection, preparation, and installation of new seismic stations. One critical component during the site selection process of any seismic network is an assessment of the seismic noise level at potential sites. The capacity of any seismic station to detect earthquakes and record high quality waveforms will be determined by the signal and noise characteristics of the site. Proper site selection is strongly related to the network's region and can be a critical issue. Besides the earth’s natural background noise, there are other noise sources to consider like those related to infrastructure close by (roads, traffic, mining activity, tenants, etc.). The goal of this work is to conduct noise surveys that can be quickly deployed in order to efficiently evaluate potential sites for the installation permanent seismic stations.An initial noise survey was conducted at two sites: one at an existing site LUBU (near Liubeshka village, Lviv district) and one at a new site SUGL (near Mala Uhol`ka village, Zakarpattia district). We analyzed, and report the data in the form of both time-history examples and standardized Probability Density Function noise plots. Seismic spectral analysis based on the calculation of Power Spectral Density distribution using a Probability Density Function by McNamara approach.
Integrated monitoring and isotope-aided modelling to assess ecohydrological fluxes and storage dynamics in a drought sensitive lowland catchment, Germany
Authors: Tetzlaff Doerthe , Smith Aaron , Luo Shuxin , Soulsby Chris
Published: March 2024

Continuing negative rainfall anomalies, coupled with climate change projections of increased drought severity and frequency, result in an urgent need to increase resilience and integration in land and water management strategies in many regions of the World. However, complex interactions between landcover change, hydrological partitioning and water availability are difficult to quantify, especially at different spatio-temporal scales. We will present insights from integrated monitoring and tracer-aided modelling approaches from the long-term experimental catchment Demnitzer Mill Creek catchment, NE Germany. We combine stable water isotopes measured at different compartments of the critical zone and landscape with process-based tracer-aided models of different complexity to investigate and quantify ecohydrological fluxes and dynamics of water storage, pathways and ages. Such tracer-aided, ecohydrological modelling frameworks provide robust science-based evidence for policy makers allowing quantitative assessment of landuse effects on water availability and effective communication with stakeholders. Our findings also underscore the urgent requirement for enhancing resilience and promoting integrated strategies in managing land and water resources to better respond to drought.
Sun-to-Earth CME Modeling with Data Assimilation and Uncertainty Quantification
Authors: Toth Gabor , Chen Yang , Huan Xun , van der Holst Bart , Jivani Aniket , Chen Hongfan , Sachdeva Nishtha , Huang Zhenguang , Manchester Ward
Published: March 2024

Supported by the Space Weather with Quantified Uncertainty (SWQU) NSF program, we have been developing the Next Generation Space Weather Modeling Framework at the University of Michigan for three years. The main goal of the project is to provide useful probabilistic forecast of major space weather events about 24 hours before the geospace impact occurs. We are using the first-principles models in the Space Weather Modeling Framework (SWMF) in combination with uncertainty quantification and data assimilation. Using the advanced MaxPro experimental design and fully automated Python scripts, we have performed thousands of solar wind background and coronal mass ejection (CME) simulations with the solar corona, inner heliosphere and eruptive event generator based on the Gibson-Low fluxrope (EEGGL) models of the SWMF. Our CME initiation model is at the surface of the Sun, so the CME can interact with the background solar wind and the magnetic field of the erupting active region. Based on these simulations, we have performed the uncertainty quantification analysis using the Bayesian inversion formula and a newly defined distance metric adapted to solar simulations. One important finding is that the physically meaningful range of the background solar wind model parameters depends on the solar cycle. We have identified the three most important parameters that impact the background solar wind model and two more parameters (the strength and helicity of the magnetic field of the fluxrope) that impact the CME eruption model. The reduced dimensionality of the parameter space enables reducing the size of the ensemble. Data assimilation provides further opportunity to improve the predictions. We are using in-situ observations at L1 prior to the CME to constrain the background solar wind and coronal white-light image observations right after the eruption to find the optimal flux rope parameters. We find that the CME arrival time error is significantly reduced to less than 5 hours by the data assimilation based on three events. Using an ensemble of simulations also provides a likely range for the various quantities of interest, including arrival time, solar wind speed and density and the BZ component of the magnetic field. The main product of the project, the Michigan Sun-to-Earth Model with Quantified Uncertainty and Data Assimilation (MSTEM-QUDA) is available as an open-source distribution at https://github.com/MSTEM-QUDA
Complex ice chemistry: A comparative study of electron irradiated ices and the formation of volatile irradiation products
Authors: Kipfer Kristina , Ligterink Niels F.W. , Wurz Peter , Tulej Marek , Galli André , Riedo Andreas
Published: March 2024

Ices are ubiquitous in the Solar System: They are found on the surfaces of planets and moons, on Kuiper belt objects, and are important constituents of cometary nuclei. The pristine ices consist mainly of simple molecules, such as H2O, N2, and CH4 [1, 2]. Laboratory experiments on the energetic processing of ice have shown that complex molecules form, including prebiotic molecules [3,4]. Furthermore, energetic processing of ices can sputter and desorb molecules from the ice, therefore populating the faint atmosphere of planetary objects.We simulate ice chemistry with laboratory experiments using the in-house designed and constructed ICEBEAR setup. Briefly, a copper sample holder is placed in a high vacuum chamber (P
Uncertainties in tropospheric ozone changes due to natural precursor emissions
Authors: Ye Xingpei , Wang Xiaolin , Li Danyang , Griffiths Paul , Archibald Alex , Zhang Lin
Published: March 2024

Accurate modelling of tropospheric ozone is crucial for understanding its climate and health effect, yet the uncertainty associated with natural ozone precursor emissions such as lightning and soil NOx is often overlooked. Here we apply a global chemical transport model, GEOS-Chem High Performance, to explore this uncertainty.The modelled present-day tropospheric ozone burden, under low to high natural NOx emissions levels (set to align with the current literature’s range), varies from 285 to 373 Tg; primarily attributed to lightning NOx uncertainty. Such a range far exceeds the ozone difference driven by anthropogenic emissions between the two most disparate SSP scenarios in 2050 (33 Tg). Ozone’s sensitivity to natural emissions is the highest around the tropical upper troposphere where ozone’s climate effect is also large, and would be even higher if anthropogenic emissions were reduced along the SSP1-2.6 pathway. At the surface, global mean warm-season ozone ranges from 32.4 to 38.8 ppbv, mainly due to soil NOx. This especially introduces large ozone uncertainties in southern hemisphere regions such as the Amazon and Australia.We also examine ΔO3-anthro, the ozone change driven by anthropogenic emissions changes up-to 2050. We found that with respect to tropospheric ozone burden, ΔO3-anthro shows limited differences between high and low natural emission levels (~13%), implying that the estimate of future changes in ozone radiative forcing is subject to less uncertainty from uncertain natural emissions than the present-day ozone radiative forcing itself. However, ΔO3-anthro related to the surface ozone exposure metric shows significant contrasts with different natural NOx emissions. The largest difference exceeds 5 ppbv (~50%) in regions such as Europe, North America, eastern China, and India. We hence stress that extra care needs to be taken when using individual models to assess ozone health risks in these densely populated regions as highly uncertain natural emissions will produce a presently unconstrained error.
Multifractal analysis of recent precipitation projections in the context of climate change
Authors: Dias Kovalczuk Pedro Henrique , Schertzer Daniel , Tchiguirinskaia Ioulia
Published: March 2024

Despite efforts to obtain consistent results, the prediction of patterns in the behavior of geophysical fields still faces many uncertainties. However, these analyses are important for studying the effects of human action on the environment and the effects reflected in climate change. There is much evidence that Multifractals are capable of describing intermittent behavior and statistical data of all orders and over a wide range of scales. Therefore, this work consists of using the multifractal framework to analyze recent precipitation projection data in France, verifying the evolution of its parameters over a relatively long period of time (from 1951 to 2100) and over space, using 12 points on French territory with a resolution of 2.8º x 2.8º. For this, the Double Trace Moment technique was applied to determine the mean intermittency codimensions, the multifractality indexes and the maximum probability singularities. These results were compared to the article by J.-F. Royer et al., C. R. Geoscience 340 (2008) to verify if projections remained consistent with changes in data and economic scenarios. Despite the differences found in the range of parameter values ​​and scaling behavior, recent data also indicated an increase in intermittency over time and presented spatial behavior similar to old projections, which reinforces the expectation of an increase in precipitation extremes in the coming decades.
Estimating Gross Primary Production (GPP) from satellite Solar-Induced chlorophyll Fluorescence (SIF) with a mechanistic model across NEON Ecoregions
Authors: Luo Zhenqi , Sun Ying , Wen Jiaming
Published: March 2024

Direct measurement of gross primary production (GPP) beyond a single leaf is a core challenge that prevents accurate quantification of global GPP and its spatiotemporal dynamics. Recent advancements in satellite Solar-Induced chlorophyll Fluorescence (SIF) retrieval offer promising opportunities, but so far incorporating satellite SIF to estimate GPP across scales is based solely on empirical linear scaling, an assumption that does not always hold at short timescales and stress conditions. In this study, we employ a process-based model, based on the mechanistic light reaction (MLR) model, to establish the link between SIF, electron transport rate (ETR), and GPP at the canopy scale using SIF retrievals from TROPOspheric Monitoring Instrument (TROPOMI) onboard Sentinel-5p. Our approach is applied across diverse NEON (National Ecological Observatory Network) ecoregions during the growing seasons of 2018-2021. We compare GPP estimates obtained from the conventional linear scaling approach and our mechanistic MLR-based approach with eddy-covariance (EC) flux tower measurements. Additionally, we analyze cross-biome variability in GPP estimates by incorporating ancillary information from hyperspectral reflectance spectra. Our findings highlight the potential of MLR for enabling satellite SIF for global GPP estimation, and the mechanistic advantage of MLR over the widely-accepted linear SIF-GPP scaling.
How do wind shear and gravity waves affect the evolution of optically thin cirrus in the tropical tropopause layer?
Authors: Jensen Eric , Ueyama Rei , Pfister Leonhard
Published: March 2024

Past investigations have shown that gravity waves can affect both when/where cirrus form in the Tropical Tropopause Layer (TTL) and the ice concentrations produced by homogeneous freezing nucleation.  Here, we use high-resolution two-dimensional simulations to investigate the impacts of wind shear and gravity waves on TTL cirrus evolution after the nucleation stage is complete.  We use a bin microphysics model to simulate the physical processes of ice crystal growth/sublimation, advection, and sedimentation.  Gravity wave temperature and wind perturbations are calculated using a Fourier series of wave frequencies with periods ranging from 1 day to near the Brunt Vaisala period, with amplitudes based on aircraft and superpressure balloon measurements.  The simulations are initialized based on high-altitude aircraft measurements of a case just after a homogeneous-freezing ice nucleation event has produced numerous small crystals in a supersaturated environment.  We show that wind shear alone rapidly alters the structure of the cloud, and strong shear can significantly reduce the cloud lifetime.  High-frequency gravity wave temperature oscillations accelerate the reduction of ice concentration as the cloud evolves.  Gravity waves can temporarily increase or decrease cloud optical depth (depending on the initial wave temperature tendencies), but the overall lifetime of the cloud is reduced by the waves.  We will further discuss the relative importance of different wave frequencies on the evolution of TTL cirrus.
CLEAR – All-Clear SEP Forecast: A NASA Space Weather Center of Excellence
Authors: Zhao Lulu , Gombosi Tamas ,   CLEAR Team
Published: March 2024

CLEAR will deliver capabilities for robust and quantifiable forecasts of the space radiation level of up to 24 hours, in support of aviation, satellites, and space exploration. Solar energetic particles (SEPs) can be accelerated over a wide range of energies extending up to GeVs. At relatively low energies (e.g., ~10 MeV), their flux intensity can exceed the background of galactic cosmic rays by several orders of magnitude. Protons of >100 MeV with elevated fluxes exceeding 1 proton flux unit are responsible for an increased astronaut exposure inside spacecraft shielding. Protons of >150MeV are very difficult to shield against as they can penetrate 20 gm cm (7.4 cm of Al, or 15.5 cm of water/human tissue). Furthermore, > 500 MeV protons can penetrate the atmosphere and pose radiation hazards to aviation. Besides protons, energetic heavy ions, e.g., Fe ions, can be of more severe radiation concerns. SEPs are hazardous not only to humans but also to electronics and other sensitive components in space, affecting satellite operations. The sparsity and high variability in terms of intensity, duration, composition,and energy spectra of SEP events make them difficult to predict. The CLEAR Center will develop, test and validate a self-contained, modular (“plug and play”) framework that includes all major elements impacting SEPs in the inner heliosphere: 4π maps of photospheric magnetic fields, corona (1 − 20Rs), inner and middle heliosphere (0.1 AU to Jupiter’s orbit) plasma environment, magnetic connectivity with respect to the solar source, flare/CME initiation, SEP seed population, flare and shock acceleration, and energetic particle transport. In addition, the framework will be able to accommodate radiation interaction models, which will be used to study the penetration of spacecraft walls, radiation effects on the terrestrial magnetosphere, and the radiation doses received by human tissues.
The Impacts of Inundating Australia on Australian Monsoon
Authors: Yang Zhiyuan , Narsey Sugata , Ryu Dongryeol , Peel Murray , Lo Min-Hui , McColl Kaighin
Published: March 2024

Large-scale perturbations in land surface characteristics have been found to induce disturbances in the overlying atmosphere via land-atmosphere coupling. The perturbations can lead to changes in hydroclimatic variables, such as precipitation and air temperature, or in atmospheric circulation patterns. However, the local and remote atmospheric responses to continental-scale changes in land surface water have not been well studied in Australia. In this study, using the Community Earth System Model 2 (CESM2) of the National Center for Atmospheric Research (NCAR), we investigate the changes in Australian monsoon, which primarily impacts the northern Australian climate, in response to an extreme surface condition: the whole Australia being treated as a shallow lake in model simulations. The simulation results show that a continental-scale lake would extend the Australian monsoon season via earlier onset and later end. We find that the most significant changes in the simulated precipitation occur during the pre-monsoon period (e.g., early October to mid November). Considering that the traditional scheme used to explain monsoonal rainfall by the theory of land-sea thermal contrasts is not consistent with the simulated precipitation patterns, this study analyzes the changes in moist static energy (MSE) budget, the simulation with a hypothetical lake features an atmospheric condition that favors the formation of precipitation: increased moisture convergence and dry static energy divergence, which might be associated with the increased net energetic forcing and export of MSE. We also confirm the dominant role of atmospheric circulation in determining the variability of precipitation over northern Australia in wet season via examining the regional moisture recycling. A relative impact computation upon components in the moisture budget shows that the dynamic component of the vertical advection of moisture contributes the most to the temporal evolution of precipitation over northern Australia in wet season.
Activation mechanism and failure process of an ancient landslide induced by landslide impact loads in China
Authors: Yu Zhaoyue , Zhan Jiewei , Peng Jianbing
Published: March 2024

On September 9, 2021, a catastrophic landslide occurred in Zhanjiaping Village, Zhenba County, Shaanxi Province, China, blocking the Yushui River and forming a landslide barrier lake. To gain a deeper understanding of this catastrophic event, we have utilized a combination of engineering geological exploration, multi-source remote sensing and geotechnical testing techniques to elucidate the dynamic evolution and formation mechanisms of the landslide. Zhanjiaping landslide is located in the core of the Luoquanyan Syncline within the Daba Mountain foreland arc structure zone, with the plunge direction of 319° and plunge of 11° along the fold axis. Zhanjiaping landslide is developed in the ancient landslide area, which is a typical sliding and tension-fracturing landslide with a very gentle sliding surface, and the volume of the landslide is estimated to be 7.44 × 106 m3. The strata in the landslide area exhibits a layered structure with alternating soft and hard formations. Under the influence of continuous rainfall, the steep slopes on the north flank of the Luoquanyan Syncline were destabilized along the bedding planes of the underlying mudstone, and forming a deposit on the gentle slope to the northeast of Zhanjiaping Village in the syncline core area. Then, affected by the landslide impact loading and rainfall infiltration, the strength of the contact surface between the paleoslide body and bedrock in the core area of Luoquanyan Syncline decreases, leading to the resurrection of the ancient landslide. However, blocked by the south flank of Luoquanyan Syncline, the downward sliding of the slide body was impeded, which in turn to both sides to undergo multiple extrusion and braking phenomena. This study provides a case study of a small landslide destabilization that eventually triggered the resurrection of a large-scale ancient landslide under the control of geological structure, which can provide a reference for the prevention and control of similar landslide disasters.
Solute transport in heterogeneous compressible aquifers under transient forcing
Authors: Tajima Satoshi , Dentz Marco
Published: March 2024

Transient forcing, such as tidal fluctuations, enhances mixing within aquifers [1, 2]. This study focuses on two pivotal characteristics of typical aquifers—heterogeneity in hydraulic conductivity (K) and compressible properties, represented by the log-hydraulic conductivity variance (σf2) and specific storage (Ss), respectively. Previous research has individually addressed the influence of these parameters on solute dynamics [3, 4, 5], yet their combined effects remain inadequately understood. Here, we explore how heterogeneity and compressibility (finite storage) in combination governs solute transport in aquifers under transient forcing. To this end, this study employs Monte Carlo particle tracking simulations, providing a comprehensive representation of K heterogeneity. The simulations yield temporal evolutions of the centre of mass and spatial concentration variance. These results are compared with those derived from analytical solutions applicable to homogeneous compressive porous media (σf2 = 0, Ss ≠ 0)  [5]. Our findings reveal that increasing values of σf2 and Ss result in a delayed temporal evolution of the centre of mass compared to the predictions of the homogeneous analytical solution. In addition, the homogeneous analytical solution with zero local dispersion predicts a consistently zero concentration variance, whereas our heterogeneous simulations demonstrate an increasing concentration variance over time. The simulations also show that the higher σf2 and Ss, the faster the temporal evolution of the concentration variance. These insights offer a deeper understanding of transport dynamics under transient forcing conditions, providing valuable information for accurate assessments of tidal impacts on salinity distributions in coastal aquifers. References[1] Oberdorfer, J. A., Hogan, P. J., and Buddemeier, R. W. (1990). Atoll island hydrogeology: flow and freshwater occurrence in a tidally dominated system. Journal of Hydrology 120, 327-340.[2] Inouchi, K., Kishi, Y., and Kakinuma, T. (1990). The motion of coastal groundwater in response to the tide. Journal of Hydrology 115, 165-191.[3] Dagan, G., Bellin, A., and Rubin, Y. (1996). Lagrangian analysis of transport in heterogeneous formations under transient flow conditions. Water Resources Research 32, 891-899.[4] Dentz, M., and Carrera, J. (2003). Effective dispersion in temporally fluctuating flow through a heterogeneous medium. Physical Review E 68, 036310.[5] Pool, M., Dentz, M., and Post, V. E. A. (2016). Transient forcing effects on mixing of two fluids for a stable stratification. Water Resources Research 52, 7178-7197.