bluuebunny/crossref_metadata_2025 huggingface dataset:
Rogue wave occurrence over planar coastal bathymetries
Authors: Karmpadakis Ioannis , Bellos Vasileios
Published: March 2024

Rogue waves have received considerable attention in recent years, with major advancements in their generation mechanisms having been defined. However, the focus of most investigations has been related to rogue wave occurrence in deep water. In contrast, far fewer results are available in shallower water depths. As such, the present work focuses on exploring the occurrence probabilities of rogue waves in coastal waters, as well as the physical mechanisms that lead to their formation. This is achieved by a thorough analysis of a very extensive experimental dataset of random waves propagating over planar beaches. More specifically, long simulations of realistic JONSWAP spectra arising in intermediate water depths have been generated at the deep end of the Coastal Flume at Imperial College London. These propagate over 3 uniform slopes with inclinations varying between 1:15 and 1:50, while being sampled by a dense array of wave gauges. The fine spatial resolution of wave gauges allows for a detailed description of large wave evolution as they travel towards the shoreline. Importantly, a parametric approach in defining the offshore forcing conditions has been adopted and covers a wide range of sea-state steepnesses and effective water depths. Taken together, 15 different storm conditions, each consisting of approximately 20,000 waves, have been considered for each bed slope configuration.In analysing these results, the occurrence of rogue waves is examined at all spatial locations across the coastal zone. We observe a considerable increase in rogue wave occurrence for reducing water depths which has not been found previously. This is particularly the case for moderately mild offshore storms. In exploring the shape of rogue waves arising at different water depth regimes, the relative importance of dispersion and nonlinearity is defined. While rogue waves arising at the deeper end of the coast resemble NewWave type events, solitary-type events become more pronounced at the shallower end. The occurrence of rogue waves in shallow water is suppressed once extensive wave breaking arises. While this is expected as a result of depth-induced wave breaking, interesting results arise for the steepest offshore conditions. Evidence suggests that waves breaking at the outer edge of the surf zone, regroup and give rise to rogue waves closer to the shoreline.Taken together, the rogue wave investigation within the present extensive experimental dataset provides evidence for their increased importance in coastal waters which has not been broadly considered so far.
Effects of Elevated Temperature on Microbial Growth and Enzyme Kinetic During Transition from Rhizosphere to Root-Detritusphere
Authors: Hosseini Seyed Sajjad , Rashtbari Mehdi , Lakzian Amir , Razavi Bahar S.
Published: March 2024

Microbial growth and enzyme activity depend on carbon availability, which strongly differs in rhizosphere and root-detritusphere. Elevated temperature is expected to intensify enzymatic processes in these spheres. However, the response of soil enzyme activity to elevated temperature may be influenced by microbial growth, driven by variations in carbon availability. Therefore, our study investigated the response of enzyme kinetic parameters to elevated temperature during transition from rhizosphere to root-detritusphere and potential linkage to microbial growth. For this purpose, we measured active microbial biomass (AMC) and growth rate (µ) through substrate-induced growth respiration, as well as kinetic parameters of ꞵ-glucosidase (GLU) in rhizosphere (six weeks after planting) and root-detritusphere (four weeks after shoot cutting) of wheat at two different temperatures, 20 ᵒC and 30 ᵒC.At both temperatures, a higher µ was observed in the root-detritusphere compared to the rhizosphere. Elevated temperatures significantly enhanced µ by 2.13 and 2.23 times in the rhizosphere and root-detritusphere, respectively. Additionally, AMB in root-detritusphere was lower than in the rhizosphere at both temperatures. Notably, at 30 ᵒC, AMB in the rhizosphere and root-detritusphere was 4.7 and 2.9 times lower than that at 20 ᵒC, respectively. The lower AMB in root-detritusphere and higher temperature, results from microbial starvation caused by rapid substrate uptake and fast growth. At 20 ᵒC, Vmax of GLU in root-detritusphere was higher than in rhizosphere, whereas at 30 ᵒC, the trend was reversed. Elevating the temperature from 20 ᵒC to 30 ᵒC within the rhizosphere resulted in an increase of 98% in the Vmax of GLU. Conversely, in the root-detritusphere, this temperature shift led to a reduction of 29% in the Vmax of GLU. The findings indicate that a reduction in AMB within the root-detritusphere leads to a downregulation of enzyme production. However, enzyme production in the rhizosphere is intricately regulated by both living roots and soil microorganisms, rendering it unaffected by changes in AMB.
Improving NWP post-processing at the Bureau of Meteorology 
Authors: Owen Benjamin , Canvin James , Gale Thomas , Hume Timothy , Johnson Robert , Mentiplay Daniel , Schubert Anja , Trotta Belinda , Whelan Jennifer
Published: March 2024

Statistical post-processing of numerical weather prediction (NWP) guidance is a crucial element of the forecast value chain, enabling the provision of reliable forecast-ready guidance tailored to the needs of users.  

For over a decade, the Bureau of Meteorology has relied on its own Gridded Operational Consensus Forecast (GOCF) system to provide calibrated, consensus-based guidance from a mix of ensemble and deterministic input models. While GOCF has been instrumental in enhancing the skill of the Bureau's forecasts and supporting increased automation of routine forecast production, this system has reached the limit of its utility in both technical execution and scientific capability. Hence the need to pivot to a new post-processing solution, particularly one that aligns with the shift towards ensemble models and probability-based forecasts. 

In 2019, the Bureau of Meteorology entered a partnership with the UK Met Office to adopt its Integrated Model Post-PROcessing and VERification (IMPROVER) system as the replacement post-processing platform. Since this time, staff at the Bureau have worked towards building a robust, extensible post-processing platform using the IMPROVER framework to replace our legacy system. In this talk we present an overview of the Bureau's implementation of IMPROVER and then reflect on the journey thus far. 

We explore our usage and adaptations to enable effective post-processing over the vast Australian domain where a greater reliance on global models is required. We highlight our incorporation of machine learning based calibration for rainfall, use of statistical downscaling, and multi-model blending to produce accurate forecasts across Australia. We present verification results benchmarking IMPROVER against our legacy system and include some discussion on future directions. 
Generation of Felsic Crust: A Fluid Transport Perspective
Authors: Aranovich Leonid , Khakimova Lyudmila , Frendak Andrey , Podladchikov Yury
Published: March 2024

Continental crust consists mainly of felsic rocks rich in silicon and aluminum, and is formed in subduction zones via processes linked to plate tectonics. Most recent models of the felsic crust formation rely on differentiation of basaltic magma generated via partial melting of mantle wedge peridotite under influence of a fluid phase liberated from subducting hydrated oceanic crust. Here we present an alternative model that invokes metasomatic alteration of mantle peridotite due to interaction with a water-rich fluid phase. The model is based on calculations of solid phase assemblages in equilibrium with a fluid saturated in major elements at varying pressure-temperature conditions. Calculations employed THERMOLAB software [1] along with thermodynamic properties of solids (both the standard state and mixing) according to [2,3] and aqueous solution models [4]. The calculations reveal that the SiO2 content in the fluid exerts major control on the solid phase assemblage. On decompression path from 2.5 to 0.2 GPa at 700oC in the model system NCMASH it changes from a six-mineral assemblage olivine (Ol) + orthopyroxene (Opx) + pargasite(Parg) + diopside + biotite + clinochlore to a three-phase Ol+Opx+Parg. The system Si/O ratio along the path increases from 0.26 (close to that of Ol, Si/O=0.25) to 0.28, thus pre-conditioning mantle protolith for subsequent melting that would generate diorite-granodiorite-granite melts.
Early-Mid Pleistocene ice core records of Antarctic and global cooling 
Authors: Shackleton Sarah ,   Allan Hills Blue Ice Coring Team
Published: March 2024

Here we present water isotope and noble gas data from the Allan Hills, Antarctica, which provide insight into the local and global climate extending through the Mid Pleistocene Transition and beyond. The Allan Hills blue ice archive provides snapshots of climate that extend well beyond continuous ice core records, but their interpretation has challenges, including complex stratigraphy, potential preservation bias, and highly thinned records.  The water isotope and noble gas data (which come from the same ice samples) suggest a statistically significant correlation between Antarctic temperature and mean ocean temperature, consistent with previous studies. However, we observe subtle differences between these climate reconstructions, including within the mid-Pleistocene transition. We discuss these datasets in the context of broader global changes, and the nuances of the Allan Hills archives.
Quantifying spatial variability of crop water use by combining eddy covariance observations with high-resolution UAV-based remote sensing
Authors: Helgason Warren , Hunter Anders , Harder Phillip , Cline Emily
Published: March 2024

Applications of precision agriculture enable water management decisions to be made at increasingly fine resolutions—smaller than which we can routinely estimate the water use from crops.  Direct measurement of crop evapotranspiration (ET) using the eddy covariance technique can provide continuous flux observations but cannot provide insight at smaller scales than the measurement footprint (~100-200m). On the other hand, remote sensing techniques based on the energy balance approach are capable of quantifying spatial patterns of ET at high resolutions but are limited to particular instances in time and cannot provide the temporal information required. In this research, we develop and evaluate a method to spatially disaggregate continuous ET measurements from eddy covariance systems. The approach is based on developing high resolution spatial maps of ET derived from a combination of UAV-thermal remote sensing energy balance modeling that is parameterized using UAV-LiDAR to measure crop canopy characteristics (leaf area index, canopy height, and vegetation fraction). Through consideration of the eddy covariance flux footprint, and the remotely-sensed spatial detail, temporally continuous spatial estimates of ET were developed. The application of this method is demonstrated for barley grown in the Canadian prairies under strongly heterogeneous field conditions.
Temporal Dynamics of Bacterial Aerosols in Haze and Sandstorm Events: Implications for Atmospheric Processes and Public Health
Authors: Shen Fangxia , Ma Jiahui
Published: March 2024

The health impacts of air pollution are deeply intertwined with the composition of pollutants, with bioaerosols—microbial particles suspended in the air—playing a critical role. Despite their importance, the behavior of bioaerosols during pollution episodes remainslargely elusive. In this study, we investigated the dynamics of bacterial aerosols over a one-week period. During the sampling period, haze and sandstorm events occurred sequentially, with a transition period in between. Haze air pollution, characterized by high levels of PM2.5, is a typical form of anthropogenic pollution, whereas sandstorm dust events, characterized by high levels of PM10, are typical natural pollutions. We applied 16S rDNA and 16S rRNA sequencing techniques to explore the total bacterial community and the active bacteria, respectively. Our results revealed distinct bacterial aerosol profiles during haze and sandstorm conditions. Notably, the greatest bacterial diversity was found in sandstorm samples, with the least diversity observed during haze periods. The bacterial aerosols during haze showed the most significant differences compared to those during the transition period, particularly when contrasted with sandstorm samples. The active bacterial profiles, as determined by 16S rRNA sequencing, were found to be dissimilar from the total bacterial communities present during sandstorms. The ecological drivers shaping bacterial community structures also exhibited distinct patterns. Our data suggest that selective forces influence the composition of active bacterial communities in sandstorm samples, as well as the total bacterial population during haze events. A common feature during both haze and sandstorm episodes was the extended residence time of bacteria in the atmosphere, implying that prolonged exposure could alter the structure of airborne bacterial communities. Additionally, our results highlight the increased presence of several pathogens or opportunistic pathogens in the active bacterial communities of sandstorm samples and the total bacteria during haze, indicating a increased health risk for humans, animals, and plants.
Detection of perceived linear structures by deer based on abrupt vegetation height changes using airborne laser scanning data.
Authors: Mikolka-Flöry Sebastian , Kunz Florian , Nopp-Mayr Ursula , Reimoser Friedrich , Hollaus Markus
Published: March 2024

Sudden changes in vegetation height are important natural structures perceived by deer which provide orientation and cover. Hence, these linear structures form potential paths through forested areas used by these animals. Nevertheless, perception of these structures not only depends on the magnitude of the height differences but also on the height of the vegetation itself, their spatial extent and geometrical complexity. Therefore an approach is necessary which not only detects these changes, which would be trivial, but also takes those additional parameters into account.Hence, we used a normalized digital surface model (nDSM) with a resolution of 1m derived from airborne laserscanning (ALS) data. As these height changes are local phenomena, local filters and morphological operations were used to extract potential pixels. Further aggregating connected pixels into connected components enabled us to prune spurious dangles, close small gaps and describe their geometrical complexity. Splitting the extracted and cleaned connected components at branch points made it possible to represent them as graphs. This opens up new possibilites to analyse these linear structures using graph algorithms which would not have been possible using solely a raster based representation.Visual analysis of initial results calculated for two provinces in Austria (Styria and Lower Austria) indicate that the extracted linear structures aggree well with prior suggestions and are valid indicators for potential corridors through forested areas. While many extracted structures run along forest borders, additional structures within forest are detected. As the developed approach is only dependent on few easily interpretable parameters it can be quickly adapted to other species or animals. 
Weathering of shelf sediments exposed during a glacial period: Evidence from geochemistry and Sr-Nd isotopes
Authors: Tripathy Gyana Ranjan , Negi Priyasha , Rout Rakesh Kumar , Bhushan Ravi
Published: March 2024

Erosion of continental rocks controls nutrient and sediment supply, soil formation and global climate. Intensity of this land-surface process is driven by both climatic (runoff, and temperature) and non-climatic (vegetation, lithology and basin slope) factors. Additionally, climatic-driven fluctuations in sea-level may also influence the exposed land-area, which is available for weathering. The coupling between exposed shelf sediments and weathering, however, has received limited attention. In this contribution, geochemical and Sr-Nd isotopic compositions of a sediment core (VM29-17PC) from the western Bay of Bengal have been investigated to reconstruct weathering and climate interaction during last glacial-interglacial cycle. Radiocarbon dating of foraminifera samples establishes that the core preserves a continuous erosional record for last 35 kyr.  Average Sr-Nd isotopic data for the decarbonated sediments confirm dominant sediment supply from the Higher Himalaya to the core site, with sub-ordinate input from the Deccan region. Temporal changes in the isotopic data hint at a sudden increase in the Himalayan source around 15 kyr BP, which is synchronous with the Bølling-Allerød (B/A) warm phase and the strengthening of the south-west (SW) monsoon. Downcore variation of Chemical Index of Alteration (CIA) and K/Al ratios indicates intensification of chemical weathering around 25 kyr BP. This change in weathering intensity is synchronous to dropping of sea level due to onset of glaciation. This sea-level regression and sudden rise in CaCO3 concentration during this period point to weathering of additional surface exposed in the shelf regions. This enhanced weathering of the shelf sediments may have contributed to the atmospheric CO2 level during the glacial period.
Quantitative Analysis of phase saturation distribution during hydrate formation and dissociation under high water saturation condition using low-field NMR
Authors: Ahn Taewoong , Lee Jaehyoung , Park Changhyup
Published: March 2024

Natural gas hydrates are known to exist in vast quantities beneath the permafrost and deep-sea sediment layers worldwide, transcending national borders, making them a promising future energy resource. While test productions have been conducted by a few countries such as Japan, China, and the United States, a commercially viable production method has yet to be established. The technologies developed so far have limitations, as laboratory-scale experiments and computational models often fail to accurately predict production behavior in actual field conditions. To achieve reliable predictions of production patterns, it is crucial to understand the changes in phase distribution within hydrate-bearing sediment layers and the corresponding multiphase fluid behavior. This study utilizes low-field Nuclear Magnetic Resonance (NMR) to quantitatively analyze phase distribution, saturation, and pore occupancy changes within rock samples during hydrate formation and dissociation processes. Particularly, experiments on hydrate formation and dissociation, along with NMR signal analysis, were conducted under conditions where water is abundant to investigate the role and influence of excessive water. In cases of high initial water saturation (presence of movable water), it was observed that the phase saturation distribution during hydrate formation becomes heterogeneous due to water migration in an unexpected manner. During the depressurization-driven dissociation process, a quantifiable increase in water saturation due to dissociated water was observed, revealing the occurrence of hydrate reformation even during the dissociation process. This research provides a methodology and analytical data to understand phenomena that are challenging to predict during hydrate formation and dissociation processes.
Numerical Weather Prediction research-to-operations updates at the US Aviation Weather Center
Authors: Cross Austin
Published: March 2024

The US National Weather Service (NWS) Aviation Weather Center (AWC) provides domestic and international aviation weather forecasts and warnings. The constituent Aviation Weather Testbed is a research-to-operations (R2O) facility that connects partners in government, industry, and academia to continually advance the state of the art of aviation forecast operations.Upcoming changes to the NWS rapid refresh modeling suite offer new opportunities with higher resolution, longer time range North American forecasts promising greatly enhanced gridded aviation forecasts. Work is underway to redevelop aviation postprocessing for airframe icing and turbulence, as are efforts evaluate all of the numerical output through multiple collaborative testbed experiments bringing together collaborators, aviation customers, airline representatives, university researchers, stakeholders and others, with widely varying backgrounds to demonstrate and evaluate ongoing efforts.AWC also operates one of the two World Area Forecast Centers (WAFC) in coordination with US Federal Aviation Administration in order to facilitate international flight operations. Following years of development and evaluation WAFC products are set to undergo significant upgrades in resolution and service capability in 2024.This presentation will discuss testbed evaluation findings including forecast performance, and detail upcoming improvements to products and services resulting from these advances. 
Improving the Aerosol-cloud-radiation Interactions in WRF-Chem-Solar and its preliminary application in China
Authors: Wang Su , Huang Gang , Dai Tie
Published: March 2024

The Weather Research and Forecasting model with solar extensions (WRF-Solar) has demonstrated potential and reliability in employing an aerosol-aware microphysics scheme as a moderate-cost alternative for aerosol-cloud-radiation and solar power simulations. However, it has not been integrated with any aerosol model due to computational cost considerations. In this study, we fully couple the Thompson and Eidhammer aerosol-aware microphysics scheme with the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model, incorporating online aerosol-cloud-radiation interactions into the WRF-Solar model. We then evaluate its performance on shortwave radiation in China in March 2021. The results show a general improvement in the model's Aerosol Optical Depth performance across most areas in China, thereby enhancing the simulation of clear-sky global horizontal irradiance (GHI). The most significant enhancement is observed in northern regions, with reductions of 24% in RMSE and 44% in BIAS. Subsequently, cloud properties and all-sky GHI are examined, revealing improvements in almost all areas except Tibet, with the most notable improvement in the Western region (56.18% reduction in BIAS for all-sky GHI). The observed underestimations in northwest areas are attributed to the overestimations of dust. This study not only provides better GHI forecasting results but also deepens the understanding of aerosol-cloud-radiation interactions in climate prediction
Enhancing Water Security through Stepwise Ecological Restoration and Nature-Based Solutions
Authors: Liu Junguo , Bezak Nejc
Published: March 2024

Approximately 48% of rivers worldwide have experienced degradation, primarily resulting from reduced connectivity. The restoration of degraded river ecosystems faces a significant challenge - the lack of comprehensive scientific understanding of hydrological and ecological processes within the broader watershed context. To address this, the synthesis of case studies from diverse countries becomes crucial, demonstrating how a deeper grasp of hydrological and ecological processes can contribute to a stepwise ecological restoration of watersheds. Furthermore, the adoption of Nature-Based Solutions (NbS) for river management remains limited, largely due to a prevailing perception that they may not be as effective as conventional grey infrastructure solutions. Some NbS aim to mitigate multiple hydro-climatic extremes, such as floods and droughts, yet their implementation often lacks a holistic approach. To tackle these issues, two working groups have been established within the HELPING Decadal Program of the International Association of Hydrological Sciences (IAHS). These groups aim to facilitate the collection of data, share case studies, and foster research collaboration in the field of stepwise ecological restoration and nature-based solutions. The ultimate goal is to develop robust tools and strategies that ensure water security while promoting comprehensive watershed restoration.
Oxic hot moments in a coastal floodplain highlight the bidirectional flow of surface water-groundwater exchanges at the terrestrial-marine interface
Authors: Ghosh Ruby , Grande Emilio , McIntire Charles
Published: March 2024

Due to their saturated conditions resulting from frequent inundations, coastal floodplains are crucial in sequestering atmospheric carbon and regulating nutrient cycling. Tidal inundations can mobilize dissolved oxygen (DO), a critical driver of biochemical function, towards the subsurface, stimulating microbial activity when DO-rich surface water mixes with anoxic groundwater (i.e., hydrodynamics of surface/groundwater exchange driven by periodic flooding). While our knowledge of these systems has improved over the years, we need a greater understanding of the spatiotemporal variability of essential biochemical drivers within tidal floodplains. Mainly, measuring DO at sufficient temporal resolution in such rapidly changing environments to resolve the relative influence of each factor is challenging, limiting our ability to predict how chronic sea-level rise will impact coastal floodplain functionality and spotlighting the urgency to fill this knowledge gap.We used a state-of-the-art optical DO probe (Opti O2) to continuously measure subsurface DO concentrations at 5 min resolution over ~4 years at Beaver Creek, a freshwater creek in Washington, USA. Following the removal of a barrier in 2014, the site floods during tidal events with water from Gray’s Harbor, located at the northwestern Pacific coast. This data set is the first measurement in a coastal environment with the requisite temporal resolution to obtain in-situ, subsurface oxygen consumption time series (see attached image). With our data, we investigate the evolution of processes following a controlled sea level rise experiment. Co-located instruments monitoring surface water and groundwater levels, salinity, and meteorological parameters (including rainfall, air temperature, barometric pressure, solar flux density) let us parse the critical drivers of coastal floodplain DO dynamics. To understand how drivers of subsurface biogeochemical processes fluctuate across tidal cycles, we used wavelet analyses to explain the interactions between DO and water levels. We observed multiple oxygenation events (34 clusters of hot moments from June 2019 to date) followed by subsequent returns to anoxia. We used information theory to explore DO’s relationship with the hydro-meteorological data. This work highlights the importance of multi-year, high-frequency in-situ measurements, such as DO, to elucidate the non-linear coupling of climate, hydrology, and biochemistry in coastal floodplains.
Compound occurrence of heat waves and drought in the Northern Hemisphere, atmospheric circulation patterns and impacts.
Authors: Castillo Natalia , Gaetani Marco , Martina Mario
Published: March 2024

The compound occurrence of heatwaves and droughts (COHWD) may result in disastrous impacts and losses across various socioeconomic sectors. Therefore, it is important to understand and predict these phenomena to support decision makers and stakeholders in implementing preparedness and adaptation measures. However, questions concerning the underlying physics that drive and potentially exacerbate these extremes in the future still remain open. This study focuses on identifying COHWD and their characteristics during the lasts 62 summers through the analysis of atmospheric variables from the ERA5, GPCC and CRU datasets in the northern hemisphere (NH). Three regions, as categorized in the latest IPCC report, are analyzed: Western & Central Europe (WCE), the Mediterranean (MED) and Eastern Asia (EAS). These regions are selected because they account for the main breadbaskets in the NH.Results show that WCE and MED have witnessed an increase in the area affected by COHWD over . In contrast, EAS does not exhibit a clear trend over the past six decades.  Moreover, by analyzing the variability of large atmospheric circulation patterns and climate oscillations, such as the North Atlantic Oscillation and the El Niño/Southern Oscillation, the dynamical drivers of COHWDs are identified. This research aims at providing new insights into the dynamical mechanisms driving COHWDs, to improve the identification, understanding, prediction and management of such events in the future. 
Super-adiabatic Temperature Gradient at Jupiter’s Equatorial Zone and Implications for the Water Abundance
Authors: Li Cheng , Allison Michael , Atreya Sushil , Fletcher Leigh , Ingersoll Andrew , Guillot Tristan , Li Liming , Lunine Jonathan , Miguel Yamila , Orton Glenn , Oyafuso Fabiano , Steffes Paul , Waite Hunter , Wong Michael , Zhang Zhimeng , Levin Steven , Bolton Scott
Published: March 2024

The temperature structure of a giant planet was traditionally thought to be an adiabat because convective mixing homogenizes entropy. The only in-situ measurement made by the Galileo Probe detected a near-adiabatic temperature structure within one of Jupiter’s 5 hot spots with small but definite local departures from adiabaticity. We analyze Juno’s microwave observations near Jupiter’s equator (0 ~ 5 oN) and find that the equatorial temperature structure is best characterized by a stable super-adiabatic temperature profile rather than an adiabatic one. Water is the only substance with sufficient abundance to alter the atmosphere's mean molecular weight and prevent dynamic instability if a super-adiabatic temperature gradient exists. Thus, from the super-adiabaticity, our results indicate a water concentration (or the oxygen to hydrogen ratio) of about 4 times solar with a possible range of 2 ~ 7 times solar in Jupiter’s equatorial region.
Tracking the Mesoproterozoic Ocean anoxia: Inferences from Mo isotopic study of black shales from Cuddapah Basin, India 
Authors: Venugopal Achyuth , Tripathy Gyana Ranjan , Goswami Vineet , Khan Tavheed
Published: March 2024

We report new chemical (trace elements and Fe-speciation) and Mo isotopic (δ98Mo) data for a Mesoproterozoic black shale sequence from the Cumbum Formation, Cuddapah Supergroup, India. These datasets have been used to reconstruct the ocean redox state and its areal extent. This reconstruction has significance in addressing the existing diverging views on the linkage between limited eukaryotic diversification and ocean oxygenation during this time period. The shales are comprised of higher organic carbon (1.1 ± 0.2 %) and sulfur (1.0 ± 0.3 %) concentrations, compared to the average upper continental crust (UCC) compositions. Most of the major elements have near-UCC values, except the lower values observed for Na, Fe and Ca. Among the trace elements, high enrichment factors for selected redox-sensitive elements (Mo, U and V) have been observed. Average Mo/TOC values (~6.3 ppm/wt%) of these shales fall close to the Proterozoic mean (~6.4 ppm/wt%). The δ98Mo values of these samples range from 0.43‰ to 1.02‰ with an average of ~0.68‰ which matches well with the Mesoproterozoic average of ~0.67‰. The Fe-speciation data indicates that the iron in these shales is mostly associated with sulfide-rich phases, with minor contribution from other phases. Average FeHR/FeT (0.61 ± 0.18) and Fepy/FeHR (0.72 ± 0.14) values indicate a fluctuating (euxinic to ferruginous) bottom water redox state in the basin. Our preliminary mass balance modelling using the Mo isotopic composition of selected (those deposited in euxinic conditions) shale samples shows that most of the oceanic Mo sink during this time were scavenged through anoxic pathways, with very little removal via oxic phases. An expanded sulfidic environment with rapid removal of bio-essential elements (hence, their reduced availability in the oceans) might have hindered the oceanic productivity and biological expansion.
Salt-driven Progressive Fracturing of Alluvial Boulders Along the Hyper-arid Shoreline of the Dead Sea 
Authors: Mushkin Amit , Boroda Ronen , Malik Uri , Lensky Nadav , Haggai Eyal , Muravin Boris , Amit Rivka
Published: March 2024

Rock weathering is ubiquitously observed at or near Earth’s surface as a fundamental component in many landscape evolution process. In arid landscapes, where limited moisture availability restricts the rate and effectiveness of chemical and biological weathering – salt weathering (regarded herein as the physical disintegration of rocks in the presence of salts) is commonly acknowledged as an especially effective mechanism for progressive weathering of rocks. While volumetric expansion and contraction of salts in response to changes in ambient moisture conditions are broadly recognized as the primary drivers of salt weathering, our understanding of the environmental conditions that produce such moisture dynamics in otherwise extremely dry settings, such as hyper-arid deserts, remains largely unknown.Here, we present preliminary results from field-based acoustic emission (AE) measurements for boulders with salt-laden cracks perched on abandoned shorelines of the hypersaline Dead Sea. Continuous measurements since April 2023 revealed daily fracturing activity displaying a bi-modal distribution with AE activity peaks during the early predawn and afternoon hours when T changes are minimal and RH fluctuations reach maximum or minimum values, respectively. Time-lapse photography revealed a recurring pattern of salts that crystalize along the rock cracks during the afternoon AE peak hours and subsequently disappear towards the predawn AE peak hours. The appearance of salt crystals during lowest RH conditions (warmest afternoon hours) and their disappearance during highest RH conditions (coldest predawn hours) suggests that stresses induced by repeated cycles of salt deliquescence/efflorescence in response to daily fluctuations in atmospheric RH are most likely responsible for the bi-modal distribution of daily fracturing activity. This suite of new field-based measurements of salt-weathering activity in natural hyper-arid settings suggests that atmospheric RH fluctuations and the volumetric changes they induce in hygroscopic salts can be key drivers of progressive rock fracturing in extremely dry and salt-rich environments on Earth and possibly Mars where other moisture sources are limited to effectively non-existent.
Crustal S-wave 3D azimuthal anisotropy beneath the southern Sichuan-Yunnan block of SW China from multiple seismic arrays
Authors: Gao Yuan , Li Ying , Yao Huajian , Tian Jianhui , Fu Yuanyuan V , Wang Qiong
Published: March 2024

The southern Sichuan-Yunnan block (SYB) is intersected by the NW-striking Honghe faults (HHF) and the nearly NS-trending Xiaojiang faults (XJF), providing an excellent zone for exploring severe crustal deformation and complicated tectonic movement. However, the crustal-mantle deformation mechanisms are still controversial, partially due to the lack of detailed information. With ambient noise data from several temporary seismic arrays and regional permanent seismic stations, we applied the direct surface wave tomography to obtain S-wave velocity and azimuthal anisotropy simultaneously. The crustal S-wave structures show complex heterogeneity both horizontally and vertically, relating to geologic settings and large faults. In the mid-lower crust, there are two significant low-velocity anomalies with strong azimuthal anisotropy, with the NNW-SSE direction near the northwest end of HHF and the NE-SW direction around the mid-south segment of XJF, respectively. The fast axis within the SYB shows approximately in the N-S direction, which differs from those in the low-velocity zones on its east and west sides. Therefore, we consider the ductile deformation in the mid-lower crust is more likely restricted by large faults. At the end of the wedged intersection, the southward mid-lower crustal flow could be blocked by the HHF, resulting in the weak materials distributed along the faults rather than crossing over at large-scale. Combining other independent studies, we conclude that there may be different deformation between the crust and the lithospheric mantle. This 3-D model provides important constraints for the regional deformations and plate tectonics of the large boundary faults [supported by NSFC Projects 42074065 & 41730212].
Adaptation mechanism of shear geomorphology in beach and trough interaction zone in the tidal zone of the Yangtze River
Authors: Chen Jinfeng , Teng Lizhi , Cheng Heqin , Jin Yang , Ren Zhongda , Zhang Hong , Zhou Quanping , Jia Zhengyang
Published: March 2024

In recent years, the upward shift of the tidal boundary of the Yangtze River has increased the intensity of shear geomorphic hazards such as bank erosion and bank failure in the middle and lower reaches of the river, but its adaptive process and mechanism to different hydrodynamic mutation zones in the beach and trough interaction zone have not been explored yet. Combining the underwater topography of Sunzhou waterway in Tongling River section, Hechangzhou North waterway and Chengchengzhou waterway in Zhenjiang River section from 1998 to 2019, and unmanned shipborne multibeam bathymetry system and ADCP power geomorphology synchronous observation in frequent nested bank failure section from 2016 to now, we analyze the characteristics of the adaptive characteristics of shear geomorphic adaptation in beach-slot interaction zones in the tidal boundary change section of the Yangtze River and the adaptive mechanism. It is found that: sand waves, scouring troughs, scouring pits, accumulators, nest ponds, nest ridges and other micro-geomorphisms are developed in the beach-trough interaction zone, and the flow direction has obvious zoning characteristics, with the mainstream zone, the mixing zone, and the reflux zone close to the shore from the trough to the shore; large and medium-sized sand waves, scouring troughs, and scouring pits are distributed in the mainstream zone, accumulators, and small-sized sand waves are distributed in the mixing zone, and the nest ponds distributed in the mixing zone and reflux zone are loaded with the nest ridges, and small-sized sand waves, The main stream and reflux zone are the main driving force for the bank failure in the beach and channel interaction zone. A sudden drop in the flow velocity in the mixing zone leads to sediment siltation and the formation of piles, and the sudden change in the hydrodynamic field in the reflux zone increases the intensity, resulting in frequent bank failures. The study can provide theoretical guidance for the risk prevention of beach and trough shear disasters.
Phosphorus Cycling and Transport in Phosphorus Saturated Soils of the Chesapeake Bay Watershed, USA
Authors: Toor Gurpal , Radolinski Jesse , Lucas Emileigh , Burgis Charles , Kennedy Bradley , Sun Fajun , Steinhilber Patricia
Published: March 2024

Long-term application of organic products (manure, biosolids, other wastes) and inorganic phosphatic fertilizers have created hot spots of phosphorus (P) saturated soils in intensive animal production regions worldwide. In such regions, P losses from P-saturated (i.e., legacy P) soils continue to plague efforts to improve water quality. Understanding the P cycling and fluxes from these P-saturated soils is critical to advancing our knowledge and developing strategies to manage P in soils and curb P losses. This presentation will discuss P cycling and transport in agricultural catchments (with Maize-Soybean rotation) from the lenses of P chemistry in soils and hydrologic responses from soils to further advancements in managing the P cycle in the soil-plant-water continuum for agricultural sustainability and environmental protection.
Magmatic Structure and Melt Storage beneath the Katmai Volcanic Group, Alaska
Authors: Hill Graham , Bedrosian Paul , Burton Bethany , Crosbie Jade , Hoogenboom Bennett , Mitchell Michael , Peacock Jared , Wallin Erin
Published: March 2024

The Katmai volcanic group (KVG) within the Alaskan Aleutian arc is an unusually dense group of active volcanic centres (Mounts Martin, Mageik, Trident, Katmai, Griggs, Snowy, and Novarupta). The KVG was the locus of the largest eruption of the 20th century. During the 1912 eruption, rhyolite was erupted from a new vent (Novarupta) contemporaneous with the collapse of nearby Mount Katmai (10 km away). A hydraulic connection has been hypothesized between the two vents based on the above observation and on a small volume of juvenile andesitic magma with the geochemical signature of Mount Katmai that erupted from Novarupta at the onset of the three-day eruption. Unanswered questions about the structure and dynamics of the KVG include the origin and storage zone for the 1912 erupted rhyolite, its connection (if any) to the dense group of andesitic stratovolcanoes surrounding the Novarupta vent, the cause for off-arc centres such as Mount Griggs, and the reason for enhanced magmatic flux beneath the KVG relative to other segments of the arc. Our recent wideband (1 kHz – 1 mHz) magnetotelluric survey of the region encompasses the entire Katmai group of volcanoes (110 sites) and is bisected by an arc-perpendicular profile crossing the Alaska Peninsula (18 sites) and spanning subducting slab depths of 60-200 km. Coast effects are present in the magnetotelluric data; however, qualitative analysis of the data indicates the Jurassic sedimentary section upon which the arc is built, the highly resistive arc itself, and a swath of elevated conductivity beneath the arc axis that likely reflects melt storage. 3D inversion of the data is ongoing.
Global investigation of the tsunamigenic dislocation of the seismic fault
Authors: Triantafyllou Ioanna , Imamura Fumihiko , Papadopoulos Gerassimos
Published: March 2024

Seismic tsunamis are produced from the sea floor dislocation (SFD) due to the earthquake rupture. The size of the SFD depends on the earthquake magnitude, depth and mechanism. The seismic moment, Mot, corresponding to the tsunamigenic SFD, is equal to k∗Mo, where Mo is the entire earthquake moment and k is a coefficient smaller than 1. For a first time, we estimated the coefficient k from published data collected for a set of tsunamigenic earthquakes that occurred in the global ocean from 1990 to 2023. The moment magnitude of these earthquakes ranges from 6.0 to 9.3. No default earthquake mechanism has been adopted. However, all the earthquakes considered are of dip-slip (thrust or normal) or oblique dip-slip types. It has been found that logk increases linearly with the earthquake moment Mo, which implies that the coefficient k increases exponentially with the Mo. For tsunami earthquakes it was found that k has a value larger than its value in regular tsunamis for the same Mo. These results provide a better understanding of the tsunami generation from earthquakes and may open possibilities for estimating the tsunami magnitude at the source.
Gendered Responses to Climate Change and the Well-Being of Girls and Women 
Authors: Carrico Amanda
Published: March 2024

It is well known that the impacts of climate change to health and well-being are exacerbated by existing social inequality. Throughout the world, women face heightened vulnerability to climate stress due to pervasive power imbalances, gender norms, and economic marginalization. Interdisciplinary collaborations that carefully integrate social and physical data are critically needed to foster a deeper understanding of the processes that increase women’s exposure. In this talk, I share findings from recent work examining the effects of extreme weather on early and forced marriage, intimate partner violence, and social isolation of girls and women. I will discuss these trends in relation to recent progress in the opportunities available to women, and offer insights into the conditions that might support women’s well-being in the face of climate risk.
Shallow geological structure by applying H/V method in volcanic area in northern Taiwan
Authors: Tseng Chia-Han , Chu Po-Yu , Wu Cheng-Feng , Rau Ruei-Juin
Published: March 2024

The Taiwan Island is the product of the orogeny resulting from the collision of the two tectonic plates, the Eurasia Continent Plate and the Philippine Sea Plate. The Philippine Sea Plate has subducted the Eurasia Continent Plate and formed Ryukyu Volcanic Arc in northern and northeastern Taiwan. The Datun Volcano Group (DVG) being located in northern Taiwan is the westernmost member of the Ryukyu Volcanic Arc and has the widest extent and largest eruption amount among the volcanic rock areas. About 1 Ma, compressional stress transformed into extensional stress in northern Taiwan, and magma from the depth erupted to form younger volcanoes (~20) in the same area. During this period, the Taipei Basin and the Jinshan Basin gradually formed as half grabens on a normal fault, namely the Shanjiao Fault.The DVG and the Shanjiao Fault have been identified to be active for micro-earthquake activities and topographical features, respectively, revealed by dense and high-resolution surficial monitoring systems in the Datun Mountain area. However, owing to rugged landscape and dense vegetations, geological boreholes are few and shallow (10 to 20 meters) so that the underground geological structures in the Datun Mountain area are still unclear. In this study, microtremor cross the presumed fault trace of the Shanjiao Fault are recorded and analyzed by applying the horizontal-to-vertical (H/V) spectral ratio method, and the H/V spectrum is further decomposed into E-W and N-S components.The H/V spectral ratio reveals different dominant frequency for different volcanic products. The results indicate that the stations on thin loose deposits (pyroclastic debris) underlying by lava flow (andesite) show the higher dominant frequency, and these stations are near crater, while the stations farther from the craters have lower dominant frequency with thick loose deposits. And these results are also consistent with the topography revealed by high-resolution digital terrain model of the Datun Mountain area.Based on the results, the future work of this study will be describing spatial geometry of the Shanjiao Fault by distinguishing different dominant frequencies corresponding to the footwall and hanging wall.
Linkage between Temperature and Heatwaves in Summer Taiwan to the Pacific Meridional Mode
Authors: Tsai Chieh-Ting , Tseng Wan-Ling , Wang Yi-Chi
Published: March 2024

Over the past century, Taiwan has gradually recognized the hazards posed by extreme heat events (EHT), prompting the development of mid-term adaptation strategies to address challenges in the coming decades. However, our understanding of decadal-scale temperature variations remains insufficient, requiring further research into influencing factors. Our study reveals the crucial role of the Pacific Meridional Mode (PMM) in modulating decadal-scale variations in summer temperatures in Taiwan. During the positive phase of PMM, warm sea surface temperature anomalies trigger an eastward-moving wave train extending into East Asia. This leads to the development of high-pressure circulations near Southeast Asia and Taiwan, enhancing the temperature increase. This mechanism has been reproduced in experiments using the Taiwan Earth System Model. Moreover, our study utilizes the calendar day 90th percentile of maximum temperature (CTX) as the threshold for extreme high-temperature events (EHT), while also employing the heatwaves magnitude scale (HWMS) as the criterion for defining heatwaves. During the positive phase of PMM, the frequency and duration of EHT increase, with variations observed across different regions. The overall intensity of heatwave events also strengthens, primarily due to extended durations. Notably, in a single city, this results in exposure of up to 800,000 person-days to EHT, presenting a tenfold increase compared to the annual effect observed in the long-term warming trend. These findings on the decadal-scale relationship between summer temperatures in Taiwan and PMM contribute to a deeper understanding of EHT and heatwaves events impacts, providing more nuanced insights for future regional strategies in mitigating heatwave disasters.