bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations of ambient aerosol and warm cloud formation in a New Mexico summer deep-convection system
Authors: Wu Huihui , Marsden Nicholas , Connolly Paul , Flynn Michael , Williams Paul , Nott Graeme , Hu Kezhen , Finney Declan , Thamban Navaneeth , Bower Keith , Blyth Alan , Choularton Thomas , Gallagher Martin , Coe Hugh
Published: March 2024

Aerosol particles can affect the formation and properties of clouds by acting as cloud condensation nuclei (CCN) and ice nucleating particles (INP). The accurate representation of aerosol size distribution and composition along with cloud nucleating properties play an important role in describing aerosol-cloud interactions. The Deep Convective Microphysics Experiment (DCMEX) is a project aimed at improving the representation of microphysical processes in deep convective clouds. The DCMEX campaign (July to Aug 2022) was conducted using the UK FAAM (Facility for Airborne Atmospheric Measurements) BAe-146 Atmospheric Research Aircraft and characterized the aerosol-cloud system over the isolated Magdalena Mountain region in New Mexico. The aircraft was equipped with a range of online instruments to measure aerosol chemical composition (i.e., Aerosol Mass Spectrometry, AMS; Laser Ablation Aerosol Particle Time of Flight mass spectrometry, LAAPToF) and aerosol size distributions, as well as cloud microphysics.A 6-days backward dispersion analysis of this region shows that the air source flow transferred from Northwest (NW, California coast) to Southeast (SE, Gulf of Mexico) during the campaign period. This air mass source change coincided with changes in meteorological parameters including such as enhancement of convection available potential energy (CAPE), decreased cloud-base height, and increased boundary layer humidity. The aerosol size distribution and chemical composition in out-of-cloud runs also show variations under different air mass source conditions. Larger sulphate and lower organic contributions were observed in the sub-micron (
Development and Application of a Model to Extract Disaster and Safety-related Information from News Big Data reported in the Media using Text Mining
Authors: Choi Sengyong , Kim Do Woo , Shin Eun Hye , Kim Yeon Ju
Published: March 2024

In Korea, when a disaster occurs, numerous news related to the disaster are reported very quickly through various media. These news contain useful disaster-related information that disaster researchers need, such as the causes of disasters, problems in the process of disaster occurrence, and improvement measures suggested by related experts. However, finding articles containing the disaster-related information we need from the numerous news reports in the media is not easy and takes a long time. Accordingly, in this study, the R-Scanner model using text mining technology was developed to extract disaster and safety information desired by users from large-scale news data, which is 'unstructured big data'. Here, R stands for Risk. The developed model was constructed based on natural language processing systems for Korean and English and was developed to perform Sentence Segmentation, Tokenization, and Morphological Analysis using text as analysis data. In the Morphological Analysis process, the model was developed to perform Entity Recognition, Semantic Role Labeling, and Semantic Chunking. Additionally, the model was developed to extract articles containing the desired information from news big data reported through the media when the user inputs keywords related to the desired information, and the extracted articles can be downloaded in Excel format. To verify the performance of the developed model, we applied it to landslides that resulted in 14 deaths due to torrential rains in Korea in 2023. Problems and improvement measures in the landslide occurrence process were set with the desired information, and keywords were set to extract each information. About 200 keywords related to problems were set, such as 'procrastination', 'defenseless', 'ignored', 'sloppy', and 'careless', and about dozens of keywords such as ‘suggested’, ‘should be prepared’, and ‘necessary’ were set as keywords related to improvement measures. As a result of applying the model, a total of 364 articles related to problems and improvement measures were extracted from 30 media news 15,911,665 articles, and as a result of grouping the extracted problems and improvement measures into similar contents, 24 problems and 22 improvement measures were finally derived. As a result of the review of related experts on the problems and improvement measures derived, it was confirmed that the contents were quite meaningful. The problems and improvement measures derived in this way were used as basic data for the establishment of government measures to prevent landslides. In the future, the developed model is expected to be used not only to establish the government's countermeasures for disaster, but also to monitor real-time disaster and safety issues, and furthermore to detect disaster risks at an early stage.
Juno Microwave Radiometer Observations into the Subsurface of the Ice Shells of Io, Europa and Ganymede
Authors: Ermakov Anton , Bolton Scott , Zhang Zhimeng , Levin Steven , Akiba Ryunosuke , Lunine Jonathan , Feng Jianqing , Hand Kevin , Keane James , Misra Sidharth , Hartogh Paul , Stevenson David , Siegler Matt , Bonnefoy Lea
Published: March 2024

On June 7, 2021, and September 29, 2022, the NASA Juno spacecraft flew by Jupiter’s Galilean moons, Ganymede, and Europa, respectively.  The closest approach distance was only ~1000 km above Ganymede, and only ~350 km above Europa. More recently, on December 30, 2023, Juno passed by Io at a distance of 1500 km and is planned do so a second Io flyby on February 3, 2024 at a similar distance.  The close flybys were the first encounters with the moons in over two decades and provided the first opportunity to map the subsurface of the their shells at multiple microwave frequencies using Juno’s Microwave Radiometer (MWR).  The observations provided several swaths across the moons at six frequencies, ranging from 600 MHz to 22 GHz.  The ice transparency at microwave frequencies is dependent on its purity; assuming pure ice, the observations probe depths ranging from meters to kilometers. The MWR observations represent the first resolved interrogation of Ganymede and Europa’s subsurface ice shell revealing new constraints on porosity, fracturing, differences in terrain type and possibly the thickness of the ice shell. These unprecedented measurements of Io, Europa and Ganymede will allow comparative studies of the surfaces and subsurface structures of the Jovian satellites. The Juno MWR measurements complement previous ground-based radar and microwave radiometry observations, which provided early characterization of these surfaces.  A comparison of the microwave spectra for all three satellites will be presented, as well as a detailed analysis and interpretation of the Ganymede MWR data that provide new constraints on ice subsurface properties.
Field Evidence for Rock Bridges Constricting the Opening of Fluid-Driven Cracks
Authors: Bunger Andrew , Dyskin Arcady , Pasternak Elena , Hill Bunker , Lau Henry , Kasperczyk Dane
Published: March 2024

A field experiment in the Western Canadian Sedimentary Basin, Alberta, Canada entails creation of a horizontal subsurface lens (fluid-driven fracture) through fluid injection from a vertical well. The initial lens creation is followed by cycling of smaller injection and flowback stages. After completion of these smaller injection/flowback cycles, the lens is (presumably) expanded through a larger scale injection followed by another series of smaller injection/flowback cycles. Tiltmeter data indicates subhorizontal lens orientation and nearly circular shape. Combining the lens radius inferred from tiltmeter inversion with measurements of downhole pressure and downhole caliper width (opening) measurements indicate the compliance is far below the linear elastic fracture prediction based on assumption that the parting between the fracture surfaces is complete and no intact rock bridges constrain opening of the lens. Additionally, the compliance is shown to increase with increasing maximum width attained by the lens. This history-dependence suggests intact rock bridges are progressively broken as larger injected volumes are used to attain larger widths. In this view, as the bridges break, the lens compliance increases. By considering a model wherein bridges are accounted for by springs with a prescribed ultimate breaking length, the observed crack compliance and dependence of the compliance on the width history are matched. Hence, the detailed field data combined with a suitable bridge constriction model comprises compelling evidence for rock bridges constricting fluid-driven crack apertures at field scale. Acknowledgements. AB, AD and EP acknowledge support from the Australian Research Council through project DP190103260.
The role of root mucilage and Extracellular Polymeric Substances in shaping soil structure and maintaining plant-soil contact
Authors: Di Bert Sara , Papadopoulou Konstantina , Duddek Patrick , Carminati Andrea , Benard Pascal
Published: March 2024

The hydraulic properties of the rhizosphere are essential for understanding root-soil interactions. Diverging from common assumptions in soil modelling, which often equate rhizosphere properties with those of bulk soil, research shows that the rhizosphere is distinct in its physical, biological, and chemical attributes.There is a broad agreement on the role of mucilage and extracellular polymeric substances (EPS) in modifying soil water dynamics in the rhizosphere. However, the mechanisms of how these substances interact with the soil matrix and impact its hydraulic properties remain unclear. In this study, we assessed the forces exerted by Xanthan gum, used as a stand-in for EPS, maize root mucilage, and water - formed liquid bridges on particle pairs.Forces were quantified for 1 microL liquid bridge between a pair of glass beads — one standing on a precision balance and the other fixed to a static stand. While the water bridges broke upon drying due to capillary forces, mucilage and Xanthan gum formed resilient filaments that maintain connectivity and tensile forces between the glass beads. The continuous recordings of weight changes by the balance provided crucial data for quantifying the force exerted on the beads during drying.Our results show that both Xanthan gum and maize mucilage liquid bridges exert tensile strengths that are substantially greater than those of water bridges. The polymer solutions initially behave similarly to water, but the forces exerted on particle pairs deviate as the solutions dry, becoming progressively stronger. The tensile strength of water reaches around 10-1 mN, while maize and Xanthan gum are respectively 1 and 2 order of magnitudes bigger. This increase is caused by the stretching of the polymer network and the development of elastic forces.The significant aggregating force observed in our study suggests that EPS and mucilage play a crucial role on the mechanics of the root-soil interface. They contribute to soil structure formation in the rhizoshere and to maintain root and soil contact as roots shrink in drying soils. 
Spatial-Temporal Rupture Characterization of Potential Tsunamigenic Earthquakes Using Beamforming: Faster and More Accurate Tsunami Early Warning
Authors: Aghaee-Naeini Amin , Fry Bill , D.Eccles Jennifer
Published: March 2024

The Vanuatu Trench hosts tsunamigenic earthquakes exceeding magnitude 7. For these source locations, current tsunami early warning systems in Aotearoa - New Zealand are based on earthquake point-source parameters and as tsunamis propagate, initial forecasts are refined by DART (Deep-ocean Assessment and Reporting of Tsunamis) sea-level analysis. This study, which is part of the R-CET (The Rapid Characterization of Earthquakes and Tsunami) project led by GNS Science, aims to seismologically characterize the spatio-temporal behavior of the regional tsunamigenic ruptures in near real-time. This transition from basic point sources to 4-D rupture propagation could enhance the accuracy of initial tsunami threat maps and hazard response. A new array of broadband seismic stations, designated as the R-CET array, has been strategically deployed in New Zealand to support this analysis for events in the South Pacific.In this proof-of-concept study, we applied a beamforming array seismological technique to analyze the R-CET array recordings from a recent tsunamigenic earthquake (Mw 7.7) in the Vanuatu region, the Loyalty Islands, on May 19, 2023. We use sliding window fk-analysis beamforming, which can simultaneously measure backazimuth and slowness. Incorporating the sliding window, in conjunction with the fk diagrams, helps to observe temporal azimuthal changes, which facilitates tracking the rupture length and direction over time. Preliminary results showed the azimuthal and temporal variation of the rupture is in alignment with post-processing estimates of the finite fault solution for this event reported by USGS. We test the utility of this analysis in tsunami forecasts by comparing threat maps generated from the beamforming source and initial response maps used in real-time response on the day. We further compare our results to actual measured coastal cancellation gauges (tide gauges) and DART observations. We show that this analysis has the potential to improve initial tsunami forecasts prior to the onset of tsunami waves at deep ocean tsunamimeters. We further present the technique as an enticing path to meet UN Ocean Decade tsunami warning goals within our framework of ensemble and time-dependent forecasting.
A GIS-based Methodology for Groundwater Potential Recharge Assessment in Sicily (Italy) through Multi Criteria Approach
Authors: Borzì Iolanda , Navarra Crisostomo , Gregorio Francesco , Lanza Stefania
Published: March 2024

Groundwater resources plays a key role in supporting human well-being, agricultural productivity, and ecological balance. Worldwide, groundwater resource represents a primary source of water supply for drinking purpose, irrigation and for supporting a variety of aquatic ecosystems, including wetlands, springs, and riparian zones. Sicily Island (Italy) relies heavily on groundwater resources, providing drinking water in different cities and water for the main island's agriculturally productive areas. In a context where climate change is expected to affect precipitation patterns and groundwater recharge rates, evaluating potential groundwater recharge areas represents an important issue for sustainable water management and for planning a proper protection of groundwater resources. For the above-mentioned reasons, we propose here a Multi-Criteria Approach (MCA) to assess potential groundwater recharge. The methodology is here implemented through geographic information system (GIS) and uses a large dataset of information for the whole Sicily Island, consisting in spatial distributed data on rainfall, evapotranspiration, aridity index, lithological characteristics of the exposed terrains, density of thrust faults and rock fractures, stream density, land uses and slope.  All the factors are firstly normalized and then used in the MCA for evaluating potential groundwater recharge areas of the entire Sicily Island through the use of different groundwater recharge rates. Results are then validated against a large dataset of wells and boreholes information for the entire region.  
Reanalyzing Jupiter ISO/SWS Data through a More Recent Atmospheric Model
Authors: Ribeiro José , Machado Pedro , Pérez-Hoyos Santiago , Dias João , Irwin Patrick
Published: March 2024

The study of isotopic ratios in planetary atmospheres gives an insight into the formation history and evolution of these objects. The more we can constrain these ratios, the better we can understand the history and future of our solar system. To help in this endeavour, we used Infrared Space Observatory Short Wavelength Spectrometer (ISO/SWS) Jupiter observations in the 793–1500 cm−1 region together with the Nonlinear Optimal Estimator for MultivariatE Spectral analySIS (NEMESIS) radiative transfer suite to retrieve the temperature–pressure profile and the chemical abundances for various chemical species. We also used the 1500–2499 cm−1 region to determine the cloud and aerosol structure of the upper troposphere. We obtained a best-fit simulated spectrum with
A Comprehensive Assessment of the AquaCrop Model in drylands: Performance Examination and Sensitivity Analysis
Authors: Almalki Ahmed S. , El Hajj Marcel M. , Johansen Kasper , McCabe Matthew F.
Published: March 2024

The AquaCrop model is a powerful tool for crop monitoring, providing a daily estimation of soil-crop-atmosphere dynamics. The model requires a substantial number of input variables and parameters, highlighting the need for identifying those that significantly influence model outputs. Sensitivity analysis is a vital method for this purpose. A key objective of this study is to examine the performance of the AquaCrop model in simulating wheat yield and irrigation water requirement in drylands under two scenarios: first running the model employing a minimal amount of in situ data, and second using all available in situ data. A second focus is to analyze the sensitivity to all crop and soil related input variables and parameters. To do this, a pilot-scale study was undertaken, focusing on a commercial farm in the Al-Jouf province of Saudi Arabia. The farm comprised 200 center-pivot fields of mainly wheat crops. In situ data was collected to calibrate the model for two consecutive growing seasons (2019-2020 and 2020-2021). Using the variance-based Sobol technique, the sensitivity of the AquaCrop model outputs, particularly wheat yield and irrigation water requirement, to crop and soil related input variables and parameters was examined, as were the influential and non-influential inputs on these outputs. Results showed that the second scenario (all data) outperformed the first (minimal data), demonstrating more accurate wheat yield predictions with rRMSE values of 17% and 21% for the 2019-2020 and 2020-2021 growing seasons, respectively. Regarding irrigation water requirement estimations, the second scenario also exhibited lower rRMSE values of 20% and 19% for the same growing seasons. Results also demonstrated that the sensitivity indices of variables and parameters varied with model outputs and growing seasons. By synthesizing inputs sensitivities under different conditions, the influential input variables and parameters were distinguished. Overall, six variables and parameters held significant influence on the analyzed model outputs based on their total-order sensitivity indices. These included duration from sowing to senescence (senescence), duration from sowing to harvesting (maturity), duration from sowing to yield formation (HIstart), base temperature below which growth does not progress (Tbase), minimum air temperature below which pollination failure begins (Tmin_up), and shape factor describing reduction in biomass production (fshabe_b). It was revealed that most variables and parameters were non-influential, which might allow them to be fixed within their ranges to optimize model calibration. The research represents the performance assessment and sensitivity analysis of the AquaCrop model over a desert farming system and offers guidelines for model calibration by delivering information on influential and non-influential input variables and parameters.
Impact of high-frequency motions on oceanic surface dispersion
Authors: Gomez-Navarro Laura , van Sebille Erik , Ubelmann Clement , Morales-Marquez Veronica , Hernandez-Carrasco Ismael , Richardson Joey , Soares Duarte , Daniel Pierre , Albert Aurelie , Molines Jean-Marc , Le Sommer Julien , Brodeau Laurent
Published: March 2024

Understanding the oceanic surface dispersion has important applications in ocean pollution scenarios. Of the different ocean pollution events, some of which have the most impact both on the marine environment and, on society and economy are: marine plastics, oil spills and Sargassum inundation events. Understanding the ocean dynamics that affect their trajectories is vital to simulate their pathways, and thus know their sources and sinks. This can then be used to implement clean-up strategies and to better manage MPAs. It can also help reduce the impact of ocean pollution on the marine environment and some major economic sectors like tourism. High frequency motions have an important impact on the surface dynamics, but high temporal resolution data is necessary to study their effects. New datasets and methodologies have allowed to obtain better representations of high frequency motions. Here, we specifically focus on the high frequency motions due to tides (like for example internal waves), as well as inertial oscillations. We simulate surface trajectories of plastic, oil and Sargassum using the OceanParcels Lagrangian simulator. We focus on three regions in the Atlantic Ocean: Açores Islands, North Atlantic and Tropical Atlantic, respectively. For the plastic simulations we look at the effect of tides by using velocity outputs from a high-resolution model which is a twin simulation without and with tidal forcing. For the oil spills and Sargassum outputs we use a new surface currents product generated by combining velocity data from drifters, high-frequency winds and altimetry to reconstruct high-frequency surface currents. We find that considering high-frequency motions is key to correctly simulate their surface trajectories, but that further work is necessary to understand the ocean dynamics at the fine-scales that can drive the variability in these Lagrangian trajectories.
Very Short-Range Precipitation Forecast in Korea Meteorological Administration
Authors: lee ho yong , Kim Jongseong , Son Joohyung , Kim Seong-Jin
Published: March 2024

Korea Meteorological Administration (KMA) has been providing the public with an hourly precipitation forecast updated every 10 minutes for the next 6 hours since 2015. This forecasts, named as the Very Short-Range Forecast (VSRF), differs from other longer forecasts ? such as short-range and medium-range forecasts issued by forecasters. The VSRF is automatically generated by a system based on two different models: MAPLE (McGill Algorithm for Precipitation nowcasting by Lagrangian Extrapolation) and KLAPS (Korea Local Analysis and Prediction System). MAPLE, based on Variational Echo Tracking (VET) from radar observations, has an intrinsic disadvantage: its performance decreases rapidly. On the other hand, numerical weather prediction systems like KLAPS are not initially as effective as MAPLE due to model balancing factors such as spin-up, but they maintain initial skill for a slightly longer period. Therefore, to provide the best predictions to the public, it is necessary to merge the two models properly. KMA conducted tests to determine the optimal way to utilize both models and established weights for each model based on their performance and precipitation tendencies. According to a 4-year evaluation, MAPLE outperforms for up to 2 hours, while KLAPS performs better after 4 hours. Consequently, the two models were merged with a hyperbolic tangent weight applied between 2 and 4 hours, and we named it as the best guidance. The best guidance was verified against precipitation observed by 720 raingauges over South Korea during the summer seasons from 2020 to 2023. It demonstrated better skill compared to both MAPLE and KLAPS. The average threat scores, with a rain intensity threshold of 0.5 mm/h throughout the forecast period, were 0.40 for the best guidance, 0.38 for MAPLE, and 0.35 for KLAPS.The best guidance depends on both MAPLE and KLAPS. Therefore, KMA is actively working to improve the performance of each model. Additionally, a very short-range model based on AI is currently under development and running in semi-operations.
Seasonality of Mixing at Tropical Instability Wave Fronts in the Atlantic Ocean 
Authors: Specht Mia Sophie , Jungclaus Johann , Bader Jürgen
Published: March 2024

Tropical Instability Waves (TIWs) in both Pacific and Atlantic Ocean have been shown to play a role in modulating upper ocean mixing. However, previous studies on the modulation of TIW related mixing are based on small numbers of TIWs. These approaches do not allow for the consideration of temporal variability, which can lead to discrepancies in the findings. In this study, we analyze 12-years of simulation output from the comprehensive, global, high-resolution ocean model ICON, to show for the first time that deep reaching mixing at TIW fronts in the Atlantic Ocean follows a distinct seasonal cycle. We find that, regardless of whether TIWs are present earlier in the year, mixing primarily occurs in boreal summer when the vertical shear of the mean zonal currents also reaches its maximum. Our results suggest that in the Atlantic Ocean, shear at the TIW fronts related to the wave itself is generally not large enough to trigger deep reaching mixing. Instead, the background shear in addition to the TIW related shear also needs to be sufficiently large to generate mixing. This additional background shear is strongly modulated by the seasonality of the South Equatorial Current (SEC). Hence, the SEC and its temporal variability contribute to the generation and modulation of deep reaching mixing at TIW fronts in the Atlantic Ocean.
Can increased cover crop diversity bind more soil in the field and mitigate overland flow erosion?
Authors: McBride-Serrano Cristina , Dodd Ian C. , George Timothy S. , Karley Alison J. , Quinton John N.
Published: March 2024

Agricultural intensification has simplified landscapes thereby reducing biodiversity, depleting natural resources, and threatening ecosystem services. Resilience to abiotic stress is therefore decreasing, creating uncertainty about effects of climate change on agricultural production and environmental degradation. While much research has focused on the direct benefits of increased plant diversity for crop productivity, there is limited evidence on how diversity and species selection affect soil stabilisation. How cover crops bind soil (rhizosheath development) has attracted little attention even though they can decrease soil erodibility.A field trial investigated the impact of cover crop diversity on rhizosheath development and soil erodibility by conducting overland flow simulations. Species (Secale cereale, Brassica juncea, Vicia faba) were chosen for their suitability to UK environmental conditions. Results established that root biomass increased with cover crop diversity and was determined by the presence of Vicia faba. Rhizosheath formation was not affected by crop diversity and was greater in treatments containing Secale cereale. Overland flow simulations showed neither rhizosheath mass nor species diversity had an impact on soil erodibility, and the field variability of soil structural and hydraulic properties had a greater influence.By providing evidence for increased plant diversity effects on agroecosystem function, this work will inform land managers about cropping practices to conserve soil function and aid in delivering environmental policy targets. 
Io Torus Electron Densities inward of Io's M-shell
Authors: Kurth William , Hospodarsky George , Faden Jeremy , Menietti John Douglas , Sulaiman Ali , Elliott Sadie , Connerney John E.P. , Allegrini Frederic , Bolton Scott
Published: March 2024

Various characteristic frequencies observed in the plasma wave spectrum inward of Io have revealed a durable electron density profile that includes a localized relative maximum near M = 4.8 with a local minimum between this and the much greater densities closer to Io.  Scale heights relative to the centrifugal equator are of order one Jovian radius, thought to be too large for a cold heavy ion population leading to the conclusion that protons are likely responsible for the large scale height.  In this paper we show evidence of the low-frequency cutoff of the z-mode at the L=0 frequency, a polarization change at the local electron plasma frequency and low-frequency cutoff of ordinary mode waves.  The determination of the electron plasma frequency and electron cyclotron frequency from the measured magnetic field strength also allow the calculation of the upper hybrid resonance frequency and R=0 cutoff of the extraordinary mode.  Often, all of these spectral features can be found in the Juno plasma wave spectra obtained in the inner Io torus.
Using stable water isotopes to improve our understanding of snow processes across scales
Authors: Wahl Sonja , Walter Benjamin , Steen-Larsen Hans Christian , Aemisegger Franziska , Dietrich Laura J. , Lehning Michael
Published: March 2024

Cryospheric processes and interactions between the cryosphere and other Earth system components are complex, host important climate feedbacks and are often difficult to measure. Yet their understanding is crucial for predicting the evolution of the cryosphere in a changing climate. Stable water isotopes are natural tracers of phase change processes within the hydrological cycle. The variability of the individual and combined isotope species offer a way to constrain environmental climatic conditions during phase change processes. Thus, they are a prime tool to investigate air-snow interactions, which are at the core of one of the most uncertain but eminently important climate feedbacks. In polar settings these phase change processes are predominantly vapor deposition and snow or ice sublimation. However, the principle of isotopic fractionation during sublimation has been controversially discussed and the usefulness of tracing stable water isotopes in cryospheric processes is thus debated.Here we demonstrate through field observations and laboratory experiments that air-snow humidity exchange leaves an isotopic fingerprint in the snow isotopic composition. We present in-situ data from the Greenland Ice Sheet and new results from cold-laboratory wind tunnel experiments. The measurements comprise isotopic signatures of snow, vapor and of the humidity flux itself. We show that snow sublimation is a fractionating process and outline how this information can be used to improve cryospheric process understanding. Specifically, we investigate the process of drifting and blowing snow by observing the evolution of both vapor and snow isotopic composition during cold-laboratory wind tunnel experiments. We document the existence of hitherto unobserved airborne snow metamorphism; a process observable on the macro-scale only through the lens of stable water isotopes. Based on the combined observations of in-situ surface humidity fluxes and wind tunnel experiments we discuss a physical explanation for the observed isotopic fractionation during snow sublimation. These insights and the data set will be the basis for determining the fractionation factors associated with airborne snow metamorphism. Our results have important implications for the interpretation of stable water isotope signals from snow and ice cores and challenge the translation of the second-order parameter d-excess signal in polar regions as moisture source signal.
Mechanical and thermal forcings of Asian large-scale orography on spring cloud amount and atmospheric radiation budget over East Asia
Authors: Li Jiandong
Published: March 2024

Asian large-scale orography profoundly influences circulation in the North Hemisphere. Considerable spring top-of-the-atmosphere (TOA) radiative cooling over Southeast China (SEC) is very likely related to upstream orography forcing. Here we investigate the mechanical and thermal forcings of Asian large-scale orography, particularly the Tibetan Plateau (TP), on downstream East Asian cloud amount and atmospheric radiation budget during March-April using the Global Monsoons Model Intercomparison Project simulations. The thermal forcing drives significant surface heating and a low-level cyclone over the TP, pumping low-level air to the middle troposphere. Ascent and water vapor convergence triggered by the thermal forcing favor air condensation, low-middle clouds, and resultant strong spring cloud radiative cooling over SEC. Moreover, the thermal forcing moves the position of cloud radiative cooling westward towards the TP. The TP’s blocking role weakens low-level westerlies over SEC, but its deflecting role increases downstream high-level westerlies, dynamically favoring cloud formation over SEC and the eastward ocean. In addition, the TP can force ascent and increase cloud amounts over the western and central TP. The thermal forcing contributes to 57.1% of total cloud amount and 47.6% of TOA cloud radiative cooling induced by the combined orography forcing over SEC while the mechanical one accounts for 79.4% and 95.8% of the counterparts over the ocean to the east of SEC. Our results indicate that Asian large-scale orography shapes the contemporary geographical distribution of spring East Asian cloud amount and atmospheric radiation budget to a large extent.
Plant paleoecophysiology traits in deep time: hydraulic conductivity and drought resistance in late Carboniferous Period plants
Authors: Wilson Jonathan
Published: March 2024

Plants have been a key interface in the global carbon and water cycles for nearly 475 million years. The magnitude of vegetational effects has waxed and waned dynamically because plant abundance and community composition have changed over time. Unravelling how plant communities have shaped, and been shaped by, global biogeochemical cycles relies upon reconstructing the paleoecology and paleoecophysiology of plants, and this process can be challenging in deep time, when plant communities contained organisms with traits that are rare in—or absent from—present-day ecosystems. Fortunately, the archive of how plants have shaped and responded to environmental change is preserved in the fossil record, because the traits and properties of extinct plants can be interpreted from fossilized anatomy in a qualitative, semi-quantitative, and quantitative way. Traits related to water transport in plants. including drought resistance and hydraulic supply to leaves, are particularly useful and important because these traits link individual plant performance to the water and carbon cycles.The collapse of tropical everwet rainforests end of the Carboniferous Period (~300 Ma) provides an illustration of how plant water transport traits influenced, and were shaped by, the water and carbon cycles. These traits are quantified by combining mathematical models of stem hydraulic conductivity and drought resistance with anatomical measurements from scanning electron and light microscopy images of fossilized plant water transport cells, called xylem. Analysis of stem hydraulic traits in five lineages of extinct Carboniferous plants—arborescent lycophytes, stem group seed plants, stem group tree ferns, coniferophytes, and sphenophytes—reveals differential hydraulic capacity and drought resistance among these plants, despite their simultaneous presence in tropical everwet ecosystems. Significant differences in these two traits are not only present between these five lineages, but can also be observed within several of these plant groups: for example, key parameters may vary by more than an order of magnitude in related plants. High hydraulic capacity and low drought resistance traits were associated with a decline in relative abundance toward the close of the Carboniferous Period, whereas plants with lower hydraulic capacity and higher drought resistance traits increased in relative abundance and survived this floral transition. This change in relative abundance within these communities shaped the hydrologic and carbon cycles which, in turn, amplified environmental stress that, consequently, further altered plant community composition. Implementing this analysis in trait-aware paleoecosystem models illustrates the effect of plant traits on global environments, and vice versa, yielding insight into plant performance during extreme environmental change that is analogous to anthropogenic impacts predicted for the late 21st century and beyond.
Climatic and ecological responses to medium-sized asteroid collision
Authors: Dai Lan , Timmermann Axel
Published: March 2024

There is a chance of 1 in 2,700 that asteroid Bennu will hit Earth in 2182 CE. The collision of such medium-sized asteroids (~0.3-1 km in diameter) with our planet can inject massive amounts of dust into the atmosphere, with unknown consequences for terrestrial and marine ecosystems. Here, we use the coupled high-top Community Earth System Model Version 2 (CESM2) with interactive chemistry to investigate how medium-sized asteroid strikes would impact climate, vegetation, and marine productivity. Our idealized simulations show that globally dispersed dust layers of up to 400 Tg in mass block shortwave radiation to the surface for nearly two years, resulting in rapid global cooling and delayed weakening of the hydrological cycle for up to four years after the impact. The combined effects of reduced sunlight, cold temperature, and decreased precipitation significantly inhibit photosynthesis in the terrestrial ecosystem for almost nineteen months. Marine phytoplankton production decreases moderately within five months due to reduced sunlight. Subsequently, however, and depending on the iron amount of the asteroid, large diatom blooms occur over the eastern equatorial Pacific and Southern Ocean due to iron fertilization from strong upwelling and dust deposition, respectively.
Mercury’s Field-aligned Currents: Hybrid Simulation Results
Authors: Shi Zhen , Rong Zhaojin , Fatemi Shahab , Dong Chuanfei , Gao Jiawei , Wei Yong
Published: March 2024

Observations from the MESSENGER (MErcury Surface, Space Environment, GEochemistry, and Ranging) mission have demonstrated the presence of the region 1-like field-aligned currents (FACs) in Mercury’s northern hemisphere. Due to the limitations of the single-point measurement, the upstream solar wind condition is blind to MESSENGER when it’s inside the magnetosphere. Thus, the statistical analyses of FACs are hard to be carried out and the results could be obscured. Here, we used a hybrid model to investigate Mercury’s FACs. The two-layer model was concerned. We studied how Mercury’s conductivity profile controls the establishment and closure of the FACs, and how the IMF orientation regulated the intensity and the spatial distributions of the FACs. Previous statistical results of MESSENGER’s observations can be well explained by the simulations. And future observations from BepiColombo will help us gain a better understanding of Mercury’s FACs. 
An experimental system capable of bidirectional fluid injection under true triaxial compression conditions for the evaluation of hydro-mechanical properties of natural barriers
Authors: Lee Yong-Ki , Choi Chae-Soon , Park Kyung-Woo
Published: March 2024

Rock masses characterized by low permeability (e.g. crystalline rocks) have been considered as natural barriers in the deep geological disposal of high-level radioactive waste. Therefore, groundwater flows within the natural barriers are typically governed by the spatial distribution of fractures within the rock mass. This study focuses on introducing an experimental system designed to evaluate hydro-mechanical properties in the natural barriers. This system allows hydro-mechanical experiments on fracture specimens by employing fluid injection under true triaxial compression conditions. The principal stress state of the underground rock mass can be induced through true triaxial compression conditions, providing the means for its application in the analysis of site-specific properties associated with rock fractures. In particular, the main feature of the experimental system is its capability for bidirectional fluid injection, allowing for hydro-mechanical experiments to be conducted on both individual and intersecting fractures. Detailed specifications have been designed considering the principal stress and groundwater conditions surrounding the KURT (KAERI Underground Research Tunnel), an underground research laboratory in Korea. The preliminary experiments utilizing the constructed experimental system confirmed that true triaxial compression conditions could be implemented while sustaining the loading speed and target stress at a reasonable level. Moreover, it was demonstrated that stable bidirectional fluid injection conditions could be achieved. The examination of applicability was also carried out by employing the experimental system to derive fracture apertures, which represent the hydro-mechanical properties of rock mass. In future investigations, we plan to conduct various hydro-mechanical experiments, employing fracture specimens sampled from the KURT site. This effort is expected to contribute to developing a Korean hydro-mechanical coupled model by evaluating the fracture properties in the KURT site.Keywords: experimental system, bidirectional fluid injection, true triaxial compression, hydro-mechanical properties, natural barriersAcknowledgements: This work was supported by the Institute for Korea Spent Nuclear Fuel (iKSNF) and the National Research Foundation of Korea (NRF) grant funded by the Korea government(Ministry of Science and ICT, MSIT) (No.2021M2E1A1085200)
Stability of ENSO teleconnections during the last millennium in CESM
Authors: Han Xue , Li Yanjie , Liu Fei , Li Jinbao , Zheng Xiaotong , Li Yan , Feng Licheng
Published: March 2024

The El Niño-Southern Oscillation (ENSO) has a significant impact on the global climate through atmospheric teleconnections. It is important to understand the stability of ENSO teleconnections, not only for future weather forecasting and climate projection, but also for ENSO reconstructions based on paleo-proxies. In this study, we investigate the decadal variations of ENSO teleconnections in global land surface temperature (LST) from 850 to 2005 AD using 13 ensemble members of the Community Earth System Model-Last Millennium Ensemble (CESM-LME). The CESM can simulate the main Eurasian cooling and Arctic warming, known as the warm Arctic-cold Eurasia (WACE) pattern, during the boreal winter of an El Niño. Furthermore, it can also capture the western Antarctic warming during the developing and decaying summers of an El Niño. There is a dominant decadal variation in the ENSO-LST teleconnections, expressed as anomalous LST patterns that closely resemble those seen in the WACE pattern during boreal winter and the western Antarctic warming pattern during summer. This decadal variation of ENSO-LST teleconnections is primarily due to the varying positions of Rossby wave sources associated with distinct ENSO patterns, which are located either to the west or to the east of Hawaii. The LST response to ENSO over South Siberia, as well as the associated precipitation response over North Eurasia, even show opposite patterns at different phases of the decadal variation. The decadal variation in CESM is found to be related to the interdecadal Pacific oscillation (IPO) and is likely attributed to internal variability rather than external forcing. Our findings suggest that the decadal variation in ENSO teleconnections should be considered when using proxies from Eurasian regions to reconstruct ENSO variability.
Extreme temperatures and respiratory mortality in the capital cities at high latitudes in Northeast China
Authors: Ma Yuxia
Published: March 2024

With the rapid increase in global warming, the impact of extreme temperatures on morbidity and mortality related to respiratory diseases has attracted considerable attention. In the current study, we quantified the relative risks (RRs) of mortality for respiratory diseases in three capital cities in Northeast China. We used a distributed lag nonlinear model (DLNM) based on a generalized additive model (GAM) to estimate the impact of extreme temperatures on respiratory mortality in Shenyang, Changchun, and Harbin from 2014 to 2016. The results revealed that the maximum cumulative RRs and 95% confidence intervals (CIs) were 1.52 (1.28–1.80), 1.42 (1.07–1.89), and 1.38 (1.21–1.58) in Shenyang, Changchun, and Harbin respectively when the median temperature was used as reference. The effect of extremely high temperature (99th percentile relative to 90th percentile) on respiratory mortality was found to be strongest in Shenyang (at the lowest latitude), while the effect of extreme low temperature (1st percentile relative to 10th percentile) on respiratory mortality was strongest in Harbin (at the highest latitude). In Shenyang and Changchun, the effects of high temperatures were much more intense and pronounced in females. Furthermore, the effect of high temperatures was more acute, whereas the effect of low temperatures was longer lasting. The results of this study could provide suggestions for reducing the impact of extreme temperatures on public health in those high latitude areas.
Machine Learning-driven Fusion of NASA’s ICESat-2 and Landsat 8 OLI Data for Assessing Forest Recovery Following Hurricane Disturbance in Southern Forests
Authors: Silva Carlos Alberto , Hamamura Caio , Klauberg Carine
Published: March 2024

The Southern U.S. hosts some of the most productive forests globally, playing a crucial role in the U.S. terrestrial carbon sink and contributing significantly to timber production (over 60% in commercial terms). Despite their importance, these forests face frequent hurricanes, leading to substantial harm to the forest structure and related ecosystem functions. This damage extends to the loss of timber supply, heightened wildfire risk, and diminished recreational opportunities. With an increasing frequency of hurricanes in the region, accurately gauging the harm inflicted on these forests becomes imperative for formulating effective protective measures and comprehending the dynamics of forest recovery.To address this issue, the study aimed to create a data fusion framework utilizing NASA's ICESat-2 and Landsat 8 OLI for mapping large-scale canopy height. This mapping would then be employed to assess the severity of post-hurricane disturbance damage and monitor forest recovery. The research utilized ICESat-2-derived canopy height estimates to calibrate a Random Forest model, predicting and mapping canopy height both before and after Hurricane Michael. The findings revealed that a combination of spectral bands and vegetation indices from Landsat 8 explained a significant portion of the canopy height variation. In areas heavily affected by Hurricane Michael in 2018, the average canopy height dropped from approximately 18 meters to 12 meters in 2019, experienced a slight increase to around 12.5 meters in 2021, and reached about 13 meters in 2022. Despite three years post-Hurricane Michael, the canopy height did not fully recover to pre-disturbance conditions.This research introduces an innovative approach to enhance forest structure mapping by integrating ICESat-2 and Landsat 8 data streams. The advancement in data fusion methodology provides an opportunity for more precise and detailed assessments of the impacts of natural disasters, such as hurricanes, on forest ecosystems in the Southern U.S