bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of glacial lakes in Southern Patagonia Icefield between 1986 and 2023
Authors: Berkhoff Jorge , Carrion Daniela , Loriaux Thomas , Wilson Ryan , Rada Camilo , Bravo Claudio , Pulgar Sebastian
Published: March 2024

This study examines the distribution and temporal evolution of glacial lakes in the Southern Patagonian Icefield (SPI) between 1986 and 2023. The question addressed is how these lakes respond to climate change, and what risks of glacial lake outburst floods (GLOFs) may arise. Monitoring these lakes is crucial due to their connection with sudden glacial water release events and their potential impact on the region.
 
A combination of Landsat and Sentinel-2 satellite images was used to detect and analyze 313 glacial lakes in the 2023 inventory. Empirical models were applied to estimate lake area and volume, highlighting the non-linear relationship between area and volume. Additionally, temporal evolution was assessed by comparing inventories from 1986, 2000, and 2015-2023.
 
In 2023, 313 lakes were identified with a total area of 639.09 km² and a volume of 34.84 km³. The majority were moraine-dammed lakes (52.72%), followed by bedrock-dammed (24.28%), and ice-dammed lakes (23%). Moraine-dammed lakes exhibited continuous growth associated with glacier retreat, while bedrock-dammed lakes showed stability, and ice-dammed lakes displayed variability and a decrease in area and volume.
 
The evolution of glacial lakes in the SPI indicates a 34% increase in number, 29% in area, and 31% in volume between 1986 and 2023. GLOF events, especially in ice-dammed lakes, highlight the importance of continuous monitoring and risk assessment. The influence of external factors, such as extreme droughts, on glacier surface melt is emphasized. The non-linear relationship between area and volume underscores the importance of considering lake size when interpreting volume changes.
The paleomagnetic results from the Early Ordovician Duoquanshan Foramtion limestone of the Oulongbuluke terrane in the Northern Tibetan Plateau
Authors: Deng Xiaohong , Zhou Yanan
Published: March 2024

The Oulongbuluke terrane, located in the northern part of the Qinghai-Tibetan Plateau, is a key area that connects the Tethys tectonic domain and the Paleo-Asian tectonic domain. However, the Early Ordovician paleogeography of this area is still unclear, which is of great significance for the understanding of the integration process of the micro-blocks in the northern Qinghai-Tibet Plateau and the closure process of the Proto-Tethys Ocean. Systematic paleomagnetism study was conducted on the Early Ordovician Duoquanshan Formation limestone from the Oulongbuluke terrane, and three components have been obtained. The medium-temperature component was obtained from 78 samples, this component is basically consistent with the paleomagnetic data of the Cretaceous period, which suggest that this component might be a remagnetization of orogenic fluids during the Yanshanian period. A stable high-temperature component (350-560 °C) is obtained in 46 sites (214 samples) and passes the fold tests, indicating that it is likely to be primary. Combined with other geological evidence, the Oulongbuluke terrane is located at the northern margin of Gondwanaland at ~15.7°S or 15.7°N (reference point: 37.2°N, 95.9°E), and near the North China Block.
The amplitude of Antarctic Ice Sheet change during the Pliocene from proxies and modelling
Authors: Gasson Edward , Lear Carrie , DeConto Rob , Halberstadt Ruthie , Pollard David , Marschalek James , Yang Zifei
Published: March 2024

Despite a major effort to constrain peak sea level during the mid-Pliocene warm period, uncertainties remain large. This interval is of interest because of the analogous CO2 concentration to present day and because of the potential retreat of a large portion of the Antarctic Ice Sheet. The usefulness of this period to constrain ice sheet model physics is limited by these large uncertainties on peak sea level. Here we discuss efforts to produce a new record of the amplitude of sea level change from interglacial to glacial periods during the early and mid-Pliocene, which have lower uncertainties than peak sea level. We combine this effort with new climate and ice sheet model simulations of the glacial to interglacial cycle for ice sheets in both hemispheres. We discuss how this work will constrain the magnitude of Antarctic Ice Sheet retreat during warm intervals of the mid-Pliocene and how we use these constraints to discriminate between different ice sheet model physics.
A journey into the Monte Amiata mafic magmatic enclaves world: from fieldwork observations to chemistry
Authors: Valeriani Lucrezia , Paternostro Simone , Sepulveda Birke José Pablo , Casalini Martina , Braschi Eleonora , Orlando Andrea , Cioni Raffaello , Francalanci Lorella , Tommasini Simone , Conticelli Sandro
Published: March 2024

Monte Amiata is a Pleistocenic volcano emplaced in a short period of time (around 300 ka) and located in southern Tuscany, where the Tuscan and the Roman magmatic provinces overlap. Its rocks range in composition from trachydacites to olivine latites and are grouped into the Bagnore Syntheme and the Monte Amiata Syntheme. The Bagnore Syntheme represents the very first phase of the Monte Amiata volcanic activity, whilst the Monte Amiata Syntheme, which includes the several domes of Mt. Amiata, two transitional formations between the domes and the Bagnore Syntheme and the two most mafic (and final) lava flows, represent the second and the third stages of the Mt. Amiata volcanic activity.  Here, we present the results of our study about the origin, the evolution, and the distribution of the mafic magmatic enclaves hosted by Monte Amiata lavas and domes. In order to do this, fieldwork observations were made, thin sections were studied under the petrographic microscope and chemical analyses on whole rocks and mineral chemistry analysis on mafic enclaves crystals have been performed. Fieldwork observations, supported by image analysis, showed a variation of the outcropping percentage abundance of the magmatic enclaves within the Monte Amiata domes. The estimated mafic enclaves abundance varies between ca. 5.5% for La Montagnola dome and ca. 0.8% in the case of the Pratini dome. This suggests a variable degree of interaction between the magmas involved in the mingling process and, in some cases, it remarks the occurrence of the mechanical fractionation. Through the petrographic investigation of the mafic enclaves at least three different groups of enclaves can be identified. They are diversified by type and abundance of phenocrysts and microliths and the presence and abundance of xenocrysts (such as, for example, sanidine, biotite and orthopyroxene). Their chemical composition ranges from olivine latites, with type “red” enclaves, to potassic trachybasalt, with type “black” enclaves. The former are characterized by abundant xenocrysts of sanidine (Or73-Or82), anhedral orthopyroxene (Mg# = 0.42-0.51) and biotite (Mg# = 0.51-0.57), and copious plagioclase phenocrysts (An83-An44) with sieve texture. The latter are marked by the occurrence of abundant phenocrysts of acicular biotite (Mg# = 0.51-0.81) and clinopyroxene (Mg# = 0.92-0.47) and minor olivine (Fo89-Fo56), often entirely surrounded by acicular microcrystals of phlogopite or biotite and visible with skeletal habit.Several disequilibrium processes among the crystals of the magmatic enclaves, such as sanidine, orthopyroxene, olivine, have been observed, suggesting complex interaction processes between different magmas.
Resolving the dynamics of microplastic transport and burial in rivers requires the incorporation of fluvial sedimentary processes
Authors: Arnon Shai
Published: March 2024

River networks are the major pathways for microplastic (MP) transport from terrestrial environments to oceans. It is essential to understand where MPs reside and how they move along river networks because of their potential to negatively impact ecosystems. However, the ability to quantify the water–sediment exchange of MPs, locations of deposition, and the time scales over which burial occurs is limited. To fill this gap, previous work on processes that control MP deposition are briefly reviewed in this presentation, with the aim of enhancing our understanding of the dynamic interplay between flow, sediment transport, and MP movement through river networks. Detailed studies on MP deposition onto surficial sediment show that MP transport can be explained by the shear stress theory, hyporheic exchange, and bioturbation. Nevertheless, these processes cannot fully explain the observed distribution of MPs in deeper river sediments. It is proposed that bedform movement, channel reworking, bar formation, and aggradation/degradation at the river network scale should be included when estimating MP deposition. It is argued that incorporating data on MP distribution in riverbeds with fluvial geomorphological and particle transport models will improve the current evaluation of MP transport in river networks and their burial residence time distribution.
A method to develop the surrogate map of emissions in China
Authors: Liu Chang , Fung Jimmy Chi Hung
Published: March 2024

As the world's population continues to grow and urbanization accelerates, emissions have become a significant contributor to air pollution and climate change. Air quality simulation is a useful tool for analyzing the impact of emissions and meteorological data on human health. In this study, we used the Weather Research and Forecasting model - Sparse Matrix Operator Kernel Emissions - Models3 Community Multiscale Air Quality Modeling System (WRF-SMOKE-CMAQ) model to explore the future air quality of Guangdong and Hong Kong.
To analyze the spatial distribution of emissions, we created surrogate maps based on cultivated land, power plants, factories, roads, and population data. We obtained five surrogate maps to estimate the spatial distribution of emissions for the agriculture, power, industry, transportation, and residential sectors. The developed surrogate maps were utilized for spatial distribution from Domain 1 to Domain 3, achieving a resolution of 3 km. By using this mapping method, we improved the PM2.5 index of agreement compared to 19 air quality monitoring stations in Hong Kong.
By combining anthropogenic emissions and marine emissions, along with downscaling meteorological data to drive the air quality model, this study provides a valuable reference for policymakers and individuals to guide actions towards air quality. Overall, our study highlights the importance of analyzing emissions and their spatial distribution to better understand their impact on air quality. 
Post fire Black Carbon alteration: Rapid changes in a supposedly inert pool
Authors: Donnerhack Oliver , Liebmann Patrick , Maurischat Philipp , Guggenberger Georg
Published: March 2024

Forest fires are among the most influential disturbances in ecosystems and have varying effects on the soil depending on fire intensity and biomass consumption. The significant decline in biodiversity in European forests due to centuries of non-sustainable forest management, combined with worsening drought from climate change, has greatly increased vulnerability to wildfires. Incomplete combustion during fires leads to the formation of black carbon (BC), a group of substances known for their persistence in soil. However, studies suggest that medium-condensed BC species may have lower chemical and spatial stability and are therefore potentially more mobile and consequently only serve as temporary carbon sinks.In order to assess the mobilization of BC, we investigate short-term changes in BC under field conditions, particularly of the low-condensed BC, and call into question the established concept of the general stability of BC pools. We investigated the dynamics of BC alterations during the post-fire period within one winter, following a late summer forest fire. We selected two comparable sites featuring spruce-dominated forest stands with different geologic parent material and weather conditions, particularly with respect to the amount of precipitation during the observation period. We sampled soil profiles down to 40 cm depth shortly after the fire event in late summer and after a 6-month period in late spring. After performing density fractionation to separate the mineral associated organic matter (MAOM) from particulate organic matter (POM), we analysed the BC content in the MAOM fraction using benzene polycarboxylic acids (BPCA) analysis.The results show a high content of low to medium condensed BPCAs directly after fire, which decreased, especially the medium condensed BPCA marker, during the observation period. Taking into account the fast change in medium BPCA values in the MAOM fraction, we conclude that the general assumption that BC is in principle a stable, long-term carbon sink needs to be addressed more carefully.
Climatic forcing on varve sedimentation regimes through the Holocene from Lake Nautajärvi, Southern Finland. 
Authors: Lincoln Paul , Tjallingii Rik , Kosonen Emilia , Ojala Antti , Martin-Puertas Celia
Published: March 2024

During the Holocene, the European high latitudes experienced substantial alterations in temperature and precipitation patterns. These changes were driven by a complex combination of factors, including the impacts of orbital and solar forcing on insolation, the dynamics of ocean-atmospheric circulation regimes, and various related feedback mechanisms. Sedimentation regimes in Boreal lakes can be sensitive to these climate changes and thus provide a valuable archive to better understand climatic forcing processes. Limitations in sampling resolution, chronological precision, and proxy sensitivity however have traditionally made continuous proxy-based palaeoclimatic reconstructions difficult to achieve through the Holocene, particularly prior to the instrumental period (c. <1800 AD). Annually laminated lacustrine or varved sediments offer significant potential to improve our understanding of sub-millennial to sub-decadal climate forcing mechanisms in sensitive regions such as the northern high latitudes. 
Here we present XRF core scanning records of a new sedimentary sequence from the dimictic Lake Nautajärvi, Southern Finland, which is continuously varved for the last 10 ka. Statistical exploration of the XRF data clearly distinguishes elements associated with detrital material (Ti, K, Si), redox conditions (Fe, Mn) and organic content ((ln(inc/coh)). Consequently, we will show how these signals can be used as proxies for different seasonal sedimentation regimes in the lake, including winter catchment snow accumulation, lake stratification induced benthic redox, and biogenic productivity during the growing season.
Spectral analysis reveals statistically significant and non-stationary decadal to multicentennial cyclicity in lake sedimentation processes through the Holocene, which align to the known Gleissberg and Suess solar cycles and periodic variability in North Atlantic atmospheric circulation regimes. Changes in these frequencies throughout the Holocene, demonstrates that different dominant external forcing mechanisms affected lake stratification and sedimentation regimes. The clearest shift occurs during the mid-Holocene, between 6 to 5 ka BP, when lake sedimentation switches from predominantly solar-cycle forced changes in stratification to decadal-centennial scale cycles in detrital influx and biogenic productivity. These shifts correspond to variability in North Atlantic circulation regimes <5 ka BP and align with trends observed in other records, indicating increased variability in the North Atlantic atmospheric circulation patterns during the mid-Holocene. Such findings highlight the valuable potential that XRF core scanning records from clastic-biogenic varved records have for tracing these non-stationary climatic changes in the high latitudes of northern Europe.
CMIP6 precipitation and temperature projections for Chile
Authors: Salazar Álvaro , Thatcher Marcus , Goubanova Katerina , Bernal Patricio , Guitérrez Julio , Squeo Francisco
Published: March 2024

Precipitation and near-surface temperature from an ensemble of 36 new state‐of‐the‐art climate models under the Coupled Model Inter‐comparison Project phase 6 (CMIP6) are evaluated over Chile´s climate. The analysis is focused on four distinct climatic subregions: Northern Chile, Central Chile, Northern Patagonia, and Southern Patagonia. Over each of the subregions, first, we evaluate the performance of individual global climate models (GCMs) against a suit of precipitation and temperature observation-based gridded datasets over the historical period (1986-2014) and then we analyze the models’ projections for the end of the century (2080-2099) for four different shared socioeconomic pathways scenarios (SSP). Although the models are characterized by general wet and warm mean bias, they reproduce realistically the main spatiotemporal climatic variability over different subregions. However, none of the models is best across all subregions for both precipitation and temperature. Moreover, among the best performing models defined based on the Taylor skill score, one finds the so-called “hot models” likely exhibiting an overestimated climate sensitivity, which suggests caution in using these models for accessing future climate change in Chile. We found robust (90% of models agree in the direction of change) projected end-of-the-century reductions in mean annual precipitation for Central Chile (~-20% to ~-40%) and Northern Patagonia (~-10% to ~-30%) under scenario SSP585, but changes are strong from scenario SSP245 onwards, where precipitation is reduced by 10-20%. Northern Chile and Southern Patagonia show non-robust changes in precipitation across the models. Yet, future near-surface temperature warming presented high inter-model agreement across subregions, where the greatest increments occurred along the Andes Mountains. Northern Chile displays the strongest increment of up to ~6°C in SSP585, followed by Central Chile (up to ~5°C). Both Northern and Southern Patagonia show a corresponding increment by up to ~4°C. We also briefly discuss about the environmental and socio-economic implications of these future changes for Chile.
Authigenic minerals development and differential diagenetic evolution of lacustrine shale: implications on formation of reservoirs and diagenetic effects of long-term CO2 sequestration
Authors: Wang Liu , Liu Bo , Bai Longhui
Published: March 2024

Determination of the mineral transformation mechanism in shale reservoirs and understanding the differential diagenetic evolution paths of various lamina combinations are of key significance to clarify the spatial development of reservoirs and predict future sealing ablitily，storage capacity for sequestered CO2. In this study, 7 wells with a maturity range of 0.6%-1.62% from Qingshankou Formation in the Songliao Basin were selected. Thin section observation combined with QEMSCAN were used to divide the types of lamina combinations. Clay mineral X-ray diffraction analysis methods, field emission scanning electron microscope, energy spectrum analysis were used to analyze the mineral textures, pore type, diagenesis path. The result show that four laminae combinations are identified of shale samples. The diagenetic development of Qingshankou Formation shale can be divided into early and middle diagenesis. Early diagenetic mineral phases include calcite cement Ⅰ, framboidal and microcrystaline pyrite, ferroan and non-ferroan dolomite. Middle diagenetic mineral phases include illitization of smectite, chlorite formed by chloritization of smectite and alteration of K-feldspar, authigenic albite and quartz,calcite cement Ⅱ，ankerite. Mechanical compaction is obvious in all laminar combination in the low mature stage. The felsic+clay, biological shell+clay, calcareous + clay laminae combination all include clay mineral transformation from the early oil generation stage and mainly develops clay mineral intercrystalline pores and interlayer crack.The main dissolved mineral particles are different in various laminar combinations in the oil window. Cementation is the main diagenesis in the biological shell+clay, calcareous + clay and carbonate lamina combination after peak oil generation stage, which has a plugging effect on pores. In addtion, the lamina combination rich in feldspar and clay minerals is beneficial to the long-term storage of CO2, while the lamina combination rich in carbonate minerals interacts is beneficial to the storage of medium and long-term carbon dioxide.
Accurate monthly forecasting of Rainfall pattern in Atlantic climates: an Empirical Fourier Decomposition-based Deep ensemble learning paradigm
Authors: Jamei Mehdi , Farooque Aitazaz Ahsan
Published: March 2024

The rainfall pattern plays a vital role in agriculture and overall climate resilience in the Atlantic provinces of Canada. Prince Edward Island and New Brunswick, two Atlantic provinces, have great potential to grow potatoes, grains, and blueberries. Thus, accurate forecasting of the rainfall pattern helps farmers determine the optimal time for planting, irrigation, fertilisation, and harvesting based on predicted rainfall patterns. Here, a new complementary multi-level intelligent framework comprised of the recursive feature elimination (RFE), Empirical Fourier Decomposition (EFD), and deep ensemble random vector functional link (Deep RVFL) has been developed to forecast the monthly (one month ahead) rainfall pattern in Charlottetown and Fredericton stations. Aiming for this, first, the significant antecedent information (lag sequences) was indicated using the RFE scheme. Then, all the optimal lags were decomposed using the EDF scheme to deduce the complexities of rainfall sub-component signals before feeding the Deep RVFL algorithm. Two comparative deep learning models, namely, RVFL and CNN-LSTM, were incorporated with the implemented multi-level pre-processing scheme in hybrid and standalone forms. In order to validate the models, several statistical indices, such as correlation coefficient (R), root mean square error (RMSE), and Kling-Gupta efficiency (KGE), scatter plots, signal trend analysis, and diagnostic assessment, were utilized. The outcomes of the results ascertained that the RFE-EDF-Deep RVFL framework, owing to superior forecasting performance, outperformed the RFE-EDF-Deep CNN-LSTM, RFE-EDF-RVFL and all the standalone counterpart models.
Development of a Continuous Flow Analysis system for studying Allan Hills, Antarctica ice cores
Authors: Hudak Abigail , Banerjee Asmita , Brook Edward , Buizert Christo , Sliwinski Maciej , Davidge Lindsey , Steig Eric , Schauer Andy , Brown Noah , Miranda Miranda , Saltzman Eric
Published: March 2024

Extending ice core records beyond 800 thousand years (kyr) is a pivotal goal in paleoclimate research. Allan Hills, East Antarctica, provides a unique opportunity to evaluate old ice and reconstruct climate well beyond 800 kyr with preliminary research uncovering ice ages up to 4.5 million years. Although old ice has been found and proven to be valuable, the ice in this area demonstrates several peculiarities—such as strong layer thinning, folding, and non-atmospheric CO2 – that warrant an in-depth investigation of the ice at this site and the climate record it holds. To address these challenges, we aim to initially conduct a high-resolution continuous flow analysis (CFA) of dust, water stable isotopes, water chemistry, and methane on the upper 70m of an ice core drilled in the 2022-2023 field season at the Allan Hills. A new CFA system has been developed at Oregon State University to analyze old ice, consisting of separate laser spectrometers for water stable isotopes and methane, an Abakus particle sensor for dust, and a fraction collector for sample analysis of melt-water chemistry.Here, we aim to present preliminary data on dust and methane and demonstrate the newly developed CFA system. Preliminary analyses on this ice have revealed the surface ice to be ~400 kyr old, with the majority of the upper 70m likely in stratigraphic order. This enables meaningful comparisons to other Antarctic ice cores and strengthens our comprehension of the climate-recording behavior of the ice. A high-resolution investigation of this ice is a critical step in understanding the discrete records from the Allan Hills that extend beyond the Mid-Pleistocene Transition and into the Pliocene, pushing our ice core records into unique and enigmatic parts of Earth’s climate history.
Sulfate Formation by Photosensitization in Mixed Incense Burning - Sodium Chloride Particles: Effects of RH, Light Intensity, and Aerosol Aging 
Authors: Tang Rongzhi , Chan Chak K.
Published: March 2024

Elevated particulate sulfate concentrations have been frequently observed in coastal areas when the air masses are influenced by continental emissions, especially combustion sources like biomass burning. We studied the SO2 uptake by laboratory-generated droplets containing incense smoke extracts and sodium chloride (IS-NaCl) under irradiation and found enhanced sulfate production over pure NaCl droplets, attributable to photosensitization induced by constituents in IS. Low relative humidity and high light intensity facilitated sulfate formation and increased the SO2 uptake coefficient by IS-NaCl particles. Aging of the IS particles further enhanced sulfate production, attributable to the enhanced secondary oxidants production promoted by the increased proportions of CHN and CHON species under light and air. Experiments using model compounds of syringaldehyde, pyrazine, and 4-nitroguaiacol verified the enhancements of CHN and CHON species in sulfate formation. This work provides experimental evidence of enhanced sulfate production in laboratory-generated IS-NaCl droplets via enhanced secondary oxidants production triggered by photosensitization in multiphase oxidation processes under light and air. Our results can shed light on the possible interactions between sea salt and burning aerosols in enhancing sulfate production.
Secondary Effects of Oil and Gas End-Use on Summertime Air Pollutants in the Eastern US
Authors: Vohra Karn , Marais Eloise , Achakulwisut Ploy , Lu Gongda , Kelly Jamie , Francoeur Colby , Harkins Colin , McDonald Brian
Published: March 2024

Oil and gas account for more than two-thirds of energy consumed in the US. The high-temperature combustion from this use yields large quantities of nitrogen oxides (NOx) that modulate the oxidative fate of isoprene, a precursor of health-hazardous air pollutants ozone, formaldehyde, and fine particulate matter (PM2.5). The COVID-19 pandemic and resulting lockdowns provided a unique opportunity to examine changes in ozone and PM2.5 linked to dramatic reduction in vehicle emissions. These occurred mostly in early spring when photochemistry is weak, biogenic emissions of isoprene are nascent, and ozone is titrated by vehicular nitric oxide (NO) emissions. Here, we use the 3D chemical transport model GEOS-Chem nested over contiguous US at a spatial resolution of 0.25º × 0.3125º (~28 km latitude × ~27 km longitude) to examine the complex influence of all oil and gas consumption or end-use activities on summertime (June-August) air pollutants in the eastern US where large cities, roadways and seasonal isoprene emission hotspots coincide. The model is driven with air pollutant precursor emissions for end-use activities from the US EPA National Emissions Inventory (NEI) for non-mobile sources and from the Fuel-based Inventory for Vehicular Emissions (FIVE) for mobile sources. We find that in the eastern US, end-use activities account for most NOx (59% of NO and 57% of nitrogen dioxide, NO2) and most (63% or 0.28 µg m-3) aerosol-phase nitrate. As ammonia, predominantly from agricultural activity, buffers aerosol acidity, end-use activities also indirectly contribute to 21% (0.10 µg m-3) of aerosol-phase ammonium. The influence on aerosol sulfate is negligible. NO from oil and gas end-use activities also modulates the proportion of isoprene that oxidizes via the NO and HO2 pathways that in turn affects yields of formaldehyde and other reactive oxygenated volatile organic compounds (VOCs) as well as isoprene secondary organic aerosol (SOA) precursors. NOx from oil and gas end-use activities enhances formaldehyde abundance by 0.3 ppb by increasing the proportion of isoprene reacting via the NO oxidation pathway that yields formaldehyde (and other oxygenated VOCs) promptly and in higher yields than the competing HO2 (low-NOx) oxidation pathway. This influence on reactive VOCs also adds 8 ppb of maximum daily mean 8-hour ozone, the metric used to assess the impact of ozone on health. Suppression of the HO2 oxidation pathway and isoprene SOA precursors only decreases SOA by 0.02 µg m-3. The net contribution of oil and gas end-use activities to PM2.5 is 1.2 µg m-3 or 12% of eastern US summertime mean PM2.5. Our results suggest multiple, substantial improvements to summertime air quality by ending reliance on oil and gas.
The ALICAT Lidar for NASA’s Atmosphere Observing System (AOS) Storm: Implications for Synergistic Diurnal Sampling of Aerosols, Clouds, and Precipitation
Authors: Nowottnick Ed , Yorks John , Selmer Patrick , Christian Kenneth , Kacenelenbogen Meloë , Midzak Natalie , Finlon Joe , Nicholls Stephen
Published: March 2024

The Atmospheric Lidar for Clouds and Aerosol Transport (ALICAT) is a SmallSat elastic backscatter lidar planned to fly in NASA’s AOS-Storm orbit with an anticipated launch in early 2029 with a planned 2-year lifetime. ALICAT will provide vertical measurements of attenuated backscatter and volume depolarization ratio at 532 and 1064 nm for aerosol and cloud profiling coincident with additional AOS-Storm instrumentation, including a Ku-band radar and microwave radiometer, in a 55-degree prescessing orbit, to target diurnal sampling of aerosols, clouds, and precipitation. ALICAT has strong design and algorithm heritage from its predecessor, the Cloud Aerosol Transport System (CATS) technology demonstration that flew on the International Space Station (ISS), but with improvements to enable enhanced dynamic range and solar background rejection for improved SNR compared to Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) that flew on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Additionally, ALICAT we employ recently developed real-time signal denoising and machine learning techniques for improved daytime SNR and feature detection at the native resolution of the raw data. This capability will deliver data products in real-time that can be readily utilized by applications community, particularly for aerosol and weather modeling, health and air quality, and aviation safety. In this presentation, we provide an overview of the ALICAT instrument and heritage, synergy with the AOS-Storm payload, projected performance and comparison to previous spaceborne atmospheric lidar instruments, and recently developed signal denoising and machine learning techniques for improved daytime feature detection.
Forecasting of flood events using two-model approach
Authors: Olbert Indiana , Moradian Sogol , AghaKouchak Amir , Broderick Ciaran , Uddin Md Galal
Published: March 2024

Floods are one of the most pervasive and costly natural disasters that result in notable socio-economic impacts. Flood forecasting systems are crucial for effective flood risk management, hazard assessment, and decision makings. However, accurate modelling and forecasting of flood events is difficult due to uncertainties in forecasting of meteorological and hydrological input variables. Forecasting is additionally complicated when floods are compound. Conventional flood forecasts typically consider only one driver at a time, whether it is ocean, fluvial or pluvial without considering the often compound nature of flood events.
In this study, a novel two-step approach to forecasting of compound coastal-fluvial floods was developed. The two-model hydrodynamic-machine learning forecasting system combines and links the hydrodynamic model with machine learning (ML) model, where the hydrodynamic outputs representing various probability flood events are used to train the ML algorithm in order to predict the inundation patterns resulting from a combination of coastal and fluvial flood drivers occurring simultaneously. In step one, the MSN_Flood model was used to simulate the compound coastal-fluvial flooding over coastal city of Cork, Ireland. In step two, the hydrodynamic model outputs such as time variable water depths across urban floodsplains were used to train the ML model. In total 7 ML models (Support Vector Regression (SVR), Support Vector Machine (SVM), Radial Basis Function (RBF), Linear Regression (LR), Gaussian Process Regression (GPR), Decision Tree (DT), and Artificial Neural Network (ANN)) were applied in this study.
Results show that the ML models, when trained on accurate hydrodynamic model outputs, can provide reliable estimates of flood inundation and associated water depths. Three ML models: RBF, ANN and DT show particularly strong performance and are found suitable for flood forecasting. In overall, the novel coupled hydrodynamic-ML system can be successfully used for flood forecasting.
Disentangling the effects of precipitation, position, and economic and size traits on wood decomposition rates across drylands
Authors: Yu Wanying , Wang Congwen , Huang Zhenying , Wang Deli , Liu Guofang
Published: March 2024

Woody plants are an important component of dryland vegetation. Research on wood decomposition in drylands has still been scarce compared with mesic ecosystems. Disentangling climate, position, and wood traits on decomposition rates is vital for understanding the carbon cycle in drylands. We studied the relative importance of economic traits including wood nitrogen, density, dry matter content (DMC) and bark weight ratio and the size trait of wood diameter class (<2, 2–4, 4–8, 8–13 and 13–20 mm) of plant species (four to five local species and one standard plant material) and position (aboveground and belowground) on wood litter decomposition rates along a precipitation gradient from 37 to 369 mm covering five sites. Decomposition rate of woody litter in buried condition was significantly higher than that on soil surface, which the position did not affect wood decomposition rates in extremely arid site. The decomposition rates of woody litters with first- and second-class diameter were higher than those of other-class diameter. The wood economics spectrum, and wood DMC and diameter were the most important drivers regulating wood decomposition rates. Woody litters with a larger size or in drier sites were characterized by higher wood DMC and density. The accelerating effect of soil burial increased with increasing annual precipitation or increasing woody litter diameter. Precipitation and wood diameter regulated woody litter decomposition rates directly and indirectly by modulating wood DMC or bark weight ratio. Our findings highlight a dual role of precipitation and stem diameter on aboveground and belowground woody litter decomposition and the effects of position on wood decomposition rates depend on precipitation and woody litter quality in drylands. Accurately measuring the wood decomposition rate in drylands and its sensitivity to macroclimate and position-mediated microenvironment would help improve the global carbon cycle models.
Hydrocarbon Potential and Mechanism of Organic Matter Enrichment of Oligocene Oil Shales in Bahcecik-Izmit Area (NW Turkiye)
Authors: Özkonuk Gökçe , Doner Zeynep , Unluer Ali Tugcan , Sutcu Naside Merve , Kumral Mustafa
Published: March 2024

Oligocene oil shales in the Bahcecik-Izmit area (NW Turkiye) are one of the alternative unconventional resources. Oil shales are rarely exposed to the high temperatures necessary for converting kerogen to oil. However, they can yield substantial quantities of combustible hydrocarbons through unconventional techniques. This study examines the determination of hydrocarbon potential and the investigation of various geochemical processes that affect the factors controlling source rock deposition of Bahcecik-Izmit oil shales.
Rock-eval pyrolysis analysis was applied to a total of 13 outcrop shale samples. The total organic carbon (TOC) content of studied shales ranges from 2.62 to 6.64 wt., with an average of 3.67 % wt. Kerogen type is mainly Type I (the hydrogen index (HI); 706-984 mgHC/gTOC). The Tmax values varying from 434 to 444oC, parameters of S2/S3 (with an average of 28.2), Production index (PI; with an average of 0.02), and related diagrams indicate that studied shales are in the thermally immature-early mature stage. Based on the S2 (with an average of 29.4 (mg HC/g TOC), genetic potential (GP; with an average of 29.9 mg HC/g TOC), and related diagrams Bahcecik-İzmit oil shales have very good-excellent hydrocarbon potential. In addition, studied shales were deposited in a lacustrine environment with a humid-warm paleoclimatic condition in oxic-suboxic environments based on several redox indicators such as V systematics (V/Sc, V/Ni, V/(V+Ni)), Ni/Co, Th/U, U/Th, and Mo/Mn ratios. The major controlling factor for organic matter accumulation can be O2-deficient conditions in the depositional environment. While a low sedimentation rate (based on the w(La)N/w(Yb)N and ΣREE values) during deposition leads to the dilution of organic matter, the paleoproductivity (based on productivity index of Ba/Al) and detrital material input (based on markers of detrital fluxes Ti, Si, Zr, Th) may have played a role in organic matter enrichment. The clay minerals may not influence organic matter preservation (based on the lack of correlation between clay-forming elements and TOC). In the end, a depositional model was established.
 
Keywords: Oil shales, hydrocarbon potential, organic matter enrichment, depositional model, Bahcecik-Izmit (NW Turkiye)
 
 
Evaluation and uncertainty assessment of a real-time regional ensemble flow forecasting system in Catalonia
Authors: Li Xinyu , Berenguer Marc , Corral Carles , Park Shinju , Sempere-Torres Daniel
Published: March 2024

A real-time flow forecasting system with significant predictability is an effective tool for facing the impacts caused by extreme weather events in the context of climate change. However, the forecasting skill is limited by the uncertainty of the different model components. The ensemble flow forecast has been frequently used to enhance the accuracy of the hydro-meteorological forecast system and describe forecast uncertainty. In this case, the assessment and enhancement of the system's performance after a long-term application and the source of uncertainty is fundamental.
This study presents an approach to evaluate the accuracy of a hydrological forecasting system that has been running in real time at a regional scale in Catalonia (NE Spain) since 2020, and generates flow forecasts in all the gauging stations of the Catalan Water Agency. The rainfall observation and precipitation forecast, which is compos the European Centre for Medium-range Weather Forecasts have been used in the modified rainfaled of 52 members, produced by the rainfall-runoff HBV model to generate probabilistic flow forecasts. The study analyzes the sources of uncertainty, and proposes guidelines to enhance the accuracy of the forecasting. The quality of the forecasts has been analyzed based on the most significant rainfall events for a period of 2 years as a function of the lead time. The observed flow information and the simulated result (0-h lead time forecast) have been compared with the forecasted flow. Both deterministic and probabilistic scores have been used in the comparison and the no-rainfall forecast has been used as a reference. The relationships between forecast accuracy and both catchment size and rainfall type have been discussed and the sources of uncertainty in the system have been explored. 
Towards a French lysimetric network: ONE WATER project
Authors: Sobaga Antoine , Habets Florence , Abiven Samuel , Faure-Catteloin Pierre
Published: March 2024

Groundwater recharge is a complex and local process which is governed by many factors. Understanding and following recharge require long term and local observations, in particular during extreme events, that are projected to be more intense due to climate change. Only lysimeters can give access directly to the recharge over long periods.
In this study, 24 lysimeters from three different sites in north-eastern France  (Homécourt-GISFI, Osne le Val-OPE Andra, Fagnières-INRAE) are used to study intense events, such as intense precipitation. The lysimeters in the 3 different sites have different dimensions, setup, soil and vegetation, which give complementary results. At Fagnières  the data achieved over 50 years present a significant decrease of the recharge, but no significant trend of the intense precipitation event nor in the associated drainage they generate. Indeed, only 10% of intense precipitation events generate drainage, in particular if the soil is uncovered and if the intense events occur in winter. These results are in line with soil water content/storage measurements of GISFI/OPE sites. 
These lysimeters are also used to assess the groundwater recharge of the land model surface ISBA, by using different soil water retention/hydraulic curves and many pedotransfer functions. 
These results reinforce the need to maintain and develop a network of lysimeters in France, to get continuous observation across the territory of groundwater recharge, but also to study other components such as the water transpired by the plant or the pollution of water. This is one of the aims of the new ONEWATER project. This network should help us to improve our understanding of the processes that can occur in the vadose zone of the soil, and to enhance seasonal forecasts from some numerical models. The main steps of this project are i) to identify and share lysimeters already available in France; ii) to create new lysimeters across the national territory to ensure spatial heterogeneity; iii) to definited an appropriated and homogeneous development method. The development of this network will largely be coordinated with CEREEP's ecotron (www.cereep.ens.psl.eu/) and the GISFI research consortium dedicated to the knowledge and the development on remediation technologies for degraded and polluted lands (www.gisfi.univ-lorraine.fr).
Constraining filtered Earth models using Backus Gilbert SOLA inferences
Authors: Mag Marin Adrian
Published: March 2024

The quality of the solution to an inverse problem depends on several factors: data quality, data quantity, and modeling approximations. In seismology, observations are limited to a finite number of measurements, sometimes resulting in small datasets. This usually leads to an ill-posed inverse problem with many solutions. Classical inversion methods remove this non-uniqueness using regularizations and model discretization. These assumptions place strong constraints on the model space and may lead to systematically inaccurate models if they lack a good physical basis.
Deterministic linear inferences, such as the Backus Gilbert (BG) SOLA method, can bypass the non-uniqueness issue by constraining properties of the unknown model, rather than the model itself. This approach also supports continuous model parameters with only mild regularizations. However, it requires a linear approximation of the data-model parameter relationship. The only regularization needed is a norm bound on the model space, which constrains the model space to a bounded subspace rather than a single point. Such prior information is less stringent than that needed for classic regularized inversions and reduces the risk of introducing subjective information into our problem.
BG SOLA has mostly been used to estimate uniform local averages of Earth's properties using seismic data. In this contribution, we show how BG SOLA can be used to constrain other types of averages and gradients through different target kernels. We also demonstrate that certain properties can be better constrained than others, depending on the data used. An advantage of our methodology is that it provides uncertainty quantification and information about the resolution of the desired property. In addition, it can be used when the data simultaneously depend on multiple physical parameters. We apply this theory to a simple application where we aim to constrain averages and gradients of Earth’s 1D structure using normal mode data. Finally, we illustrate the advantages of our methodology by comparing our results with those obtained using regularized inversion methods.
El Niño 2023-24: a rotational signature?
Authors: Lambert Sébastien
Published: March 2024

Monster ENSO events in 1982-83, 1997-98, and 2015-16 gave birth to sharp millisecond-level variations in the Earth's length-of-day (LOD). For each of these events, the sudden slowing down of the Earth as well as tis re-acceleration few days after was explained by the action of mountain and friction torques. Nevertheless, the contribution of each of these torques was pretty different in the first two events - that were true Eastern Pacific events with an SST anomaly nearing South American coasts - and in the latest - that was a hybrid Central-Eastern Pacific event with a friction over Easter Pacific astonishly contributing to slow down the Earth's rotation while it is usually balancing the mountain torque. Mid-2023, an upcoming 'monster' event was announced. At the time I write this abstract, the expected rise in LOD has not occurred. Would it occur in the coming days or not, the ONI index indicates a strong ENSO event and the examination of the Eastern and Central Pacific indices (from, e.g., Takahashi et al. 2011) reveals a hybrid event comparable to some extent with 2015-15. In this study, I propose to examine the mechanisms of interaction between the atmosphere and the solid Earth during the 2023-24 event, compare with previous ones, and investigate general trends in the link between ENSO, other prominent oscillations, and Earth's rotation.
 
Numerical simulation on pile-soil interaction under seismic loading in liquefiable ground
Authors: Wang Hao
Published: March 2024

Liquefaction is one of the main causes of pile foundation failure under earthquake loading. To solve this problem, seismic responses of pile foundation are typically analyzed by centrifugal shaking table test and numerical model. In this paper, a 3-D numerical model is established based on the open-source finite element platform (OpenSees). The PDMY02 multi-yield plastic model is adopted to simulate the dynamic behavior of saturated sand, with soil simulated by u-p fluid-solid coupling element and pile by beam-column elastic element respectively. Based on the data of centrifuge test of single pile, the validity of the numerical model is verified; and the influences of the upper structure mass, pile head fixation and ground inclination on the seismic response of single pile are analyzed. The results show that soil liquefaction can increase the lateral displacement and bending moment of single pile; the mass block at pile cap can magnify the pile inertial force and increase the pile-soil interaction, resulting in the augment of lateral displacement and bending moment; pile head fixation can effectively reduce lateral displacement, but intensify bending moment; sloping ground has a key influence on the pile dynamic response, and greater inclination leads to larger lateral displacement and bending moment of single pile.