bluuebunny/crossref_metadata_2025 huggingface dataset:
Late Cretaceous reactivation of a Paleo-Tethyan suture zone in Xizang of western China: extensional collapse of the proto-Tibetan plateau?
Authors: Liang Xiao , Wang Genhou , Bons Paul , Zhang Bo , Cao Wentao , Zheng Yilong , Zhao Zhongbao
Published: March 2024

The deformation of the Himalaya-Tibetan plateau remains one of the hottest examples of Earth's tectonics and dynamic evolution. What drives deformation and growth of the plateau, and how this is partitioned into diverse structural styles and mechanisms remain heated discussions. Mesozoic orogens also contributed to crustal thickening of the plateau prior to the Cenozoic India-Asia collision and notably, they were reactivated due to its structural inheritance and low viscosity since the collision, for example, the first uplift in Qiangtang and the Paleo-Tethyan suture zone in its interior. However, few attention was paid to pre-collision reactivation and structural superimposition of Mesozoic orogens. The newly discovered NWW-trending Ejiumai shear zone with biotite 40Ar/39Ar and zircon and monazite U-Pb ages of ca. 80-70 Ma flanks the northern border of the Paleo-Tethyan suture zone and mainly includes reactivated Triassic basement gneisses and syntectonic pegmatite. Combined with the oblique moving kinematics including both sinistral and normal-sense shear, a transtension regime with lower crustal anatexis can be concluded for the genesis of Ejiumai shear zone. Concurrent granitic plutons were also found in the suture hundreds of kilometers to the east. Based on these observations, we present a schematic model of extensional collapse of the proto-Tibetan plateau induced by far-field northward indentation of Neo-Tethyan suture zone to the south in Late Cretaceous.
Forest carbon fluxes and climate change: coupling structural and functional data to understand ecosystem responses.
Authors: Oddi Ludovica , Morra di Cella Umberto , Cremonese Edoardo , Filippa Gianluca , Grosso Federico , Vacchiano Giorgio , Migliavacca Mirco , Galvagno Marta
Published: March 2024

Forest ecosystems play a crucial role in mitigating climate change through carbon (C) sequestration (i.e., photosynthesis). However, the increasing frequency and intensity of climate extremes, especially heatwaves and drought events, are affecting the balance between C uptake and C loss in terrestrial ecosystem, resulting in decreasing CO2 sequestration from the atmosphere and storage as plant biomass. Reaching the ecosystem tipping point, with the consequent transition from carbon sinks to carbon sources, is a concrete risk.
Climate change has the potential to alter different forest processes in complex ways, showing high variability across space and time, and impacting ecological processes at different spatial scales, from the individual trees to the whole ecosystem. The structure of forests and the diversity in vegetation distribution may act as a form of insurance against these environmental changes, but the understanding of the mechanisms behind forest resistance and resilience to climate change require further investigation.
The primary objective of the present study is to establish a quantitative link between the functional and structural properties of a European larch forest located in the Western Alps, within the Aosta Valley (Italy) at an altitude of around 2100 meters a.s.l. (Larix decidua Mill., IT-Trf, LTER site: LTER_EU_IT_078).
To achieve this goal, the study take advantage of different methods. The main approach is represented by the eddy covariance method to measure C fluxes at two levels: 1) whole forest ecosystem and 2) understory vegetation. Biometric measurements of tree growth, performed in 2020, aimed at quantifying the carbon allocated to the wood biomass as structural carbohydrates. Additionally, satellite and UAV-based LiDAR observations were used to analyse the structure and composition of various vegetation layers.
Results revealed that only a small fraction of the total CO2 sequestered by the ecosystem contributes to tree stem growth. Furthermore, due to the openness of the larch forest stand, the understory vegetation accounts for approximately 30% of the total ecosystem's gross primary productivity. These findings underscore the intricate relationship between forest structure, overall ecosystem function, and the specific roles played by various vegetation components.
Strong Interplanetary Evolution of Coronal Mass Ejection from BepiColombo at 0.67 AU up to Mars
Authors: Chi Yutian , shen chenglong , mao dongwei , wang yuming
Published: March 2024

The goal of this study is to understand the magnetic field evolution of an ICME event detected by pairs of aligned spacecraft at different heliocentric distances. In this work, we report a CME event that was detected by the BepiColombo spacecraft (0.67 AU) and Tianwen-1 & MAVEN (1.66 AU) in-situ measurements, respectively. We found that the dependence of the maximum (mean) magnetic field strength of the ICME at the two points decreases with heliocentric distance as r−1.07 (r−1.29). The axial magnetic field strength (B0) derived from the force-free flux rope model decreases with heliocentric distance as r−1.78, suggesting that the in-situ observations may show the CME may not expand in a self-similar manner due to the spacecraft crossing the flux rope in a different region. The axial magnetic flux and helicity of the magnetic cloud decreased approximately 13% and twist increased 17% from BepiColombo spacecraft to Mars, which implies that the CME event was eroded by the ambient solar wind. Utilizing the deflection in interplanetary space, we reconstruct the trajectory of the CME spanning from 21.5 Rs to 342 Rs under the constraints of the CME initial velocity and the simulated solar wind velocity. We present solid evidence that the fast CME event was deflected toward the east in the interplanetary, by approximately 16◦ at BepiColombo and 31◦ at Mars. The axis of the CME shows a clear clockwise rotation from 10.27◦ at BepiColombo to -12.45◦ at Mars.  The 3D coronal rope ejection model (3DCORE) model, the deflection in interplanetary space (DIPS) model and the reconstructed CME magnetic field structure and orientation from the Force-free flux rope fitting model were found to be in good agreement with each other. The analysis of this event highlights the inherent innovative potential in Tianwen-1’s magnetometer data, presenting a novel avenue for investigating magnetic clouds encircling Mars. Observations capturing the same magnetic cloud at various heliocentric distances present an unprecedented opportunity to scrutinize the cloud’s magnetic properties and their nuanced evolution relative to distance.
The use of crop models to assess crop production and food security
Authors: Gavasso Rita Yohanne , Papalexiou Simon , Li Yanping , Elshorbagy Amin , Li Zhenhua , Schuster-Wallace Corinne
Published: March 2024

The global food supply and food security are altered by field, soil, and weather conditions during crop production. Researching food productivity became crucial as the global population increased. In particular, crop losses bring low food supply and price instabilities at the regional and global levels. With that in mind, we reviewed ten crop models and the most simulated impacts from soil-crop-atmosphere interactions in maize, rice, and wheat production. Since 2012, modellers have mainly used APSIM to predict water availability, temperature changes and Greenhouse Gas  (GHG) concentration to predict crop phenology, growth and development, grain filling and nutrient content, and yield. Since 2013, AquaCrop has been used to simulate scenarios focused on water balance in crop production systems, water stress and irrigation planning. Interestingly, Biome-BGCMuso was developed as a biogeochemical model and was not considered good by crop modellers. However, After updates, version v6.2 can simulate different management and field conditions for fifteen crops, considering heat, nitrogen and drought stress. Since 2008, crop modellers used CropSyst to evaluate water availability, nitrogen use efficiency (UE), temperature shifts and GHG concentration in rainfed and irrigated crop systems. Since 2002,  crop modellers have used DAISY to predict crop growth, nitrogen and water UE, grain content, yield gap, and losses. Since 2011, researchers have used DSSAT-CERES for mitigation strategy planning by predicting crop growth, soil characteristics, changes in land use, and nitrogen and water UE. Since 2015, JULES has been used to determine land-atmosphere interactions, changes in land use and GHG impacts on agriculture. Since 2008, ORYZA modellers have mainly predicted nitrogen and water UE, salinity impacts, and toxicity to rice. STICS was developed in 1996, and since 2008, it has been primarily used to simulate fertilization and irrigation systems, nitrogen leaching, and water availability. Since 2000, researchers have used WOFOST to analyze water availability, crop growth, and productivity under temperature changes. Crop models are fast and reliable resources when simulating crop production and food availability.
Monitoring crop phenology applying biophysical indices from Sentinel-2 data: the case of Thessaly region in Greece
Authors: Dalezios NIcolas , Faraslis Ioannis , Alpanakis Nicolas , Tziatzios Georgios , Spiliotopoulos Marios , Sakellariou Stavros , Sidiropoulos Pantelis , Dercas Nicholas , Brissimis Vagelis
Published: March 2024

The newest Earth Observation optical sensors, such as Sentinel-2, provide global biophysical products and vegetation indices at high spatial (decametric or twentimetric resolution) and temporal resolution (about 5 days retrieval). These biophysical parameters are essential for constant crop status monitoring at local scale. Optimizing the water use for irrigation, the weed mapping, quantifying ground above biomass and crop yield production, are some of the benefits of biophysical parameters in agriculture. This research investigates the crop status during the 2021’s growing season in Thessaly agricultural area in Greece. Thus, in maize, biophysical variables, and vegetation indices, that is, Leaf Area Index (LAI), fraction of absorbed photosynthetically active Radiation (FAPAR), Fraction of Vegetation Cover (FVC), Leaf Chlorophyll content (Cab), Canopy Water Content (CWC), Normalized Difference Vegetation Index (NDVI) and Normalized Difference Red Edge Index (NDRedEdge) are retrieved. The PROSAIL radiative transfer model by artificial neural network approach is employed (available of the free SNAP® software) to retrieve the biophysical parameters from Sentinel-2 multispectral imagery. The monitoring of the abovementioned biophysical variables during the growth period of maize crop shows a uniform behavior. Finally, high consistency among vegetation parameters confirms the usefulness of Sentinel-2 products in agriculture.Keywords: Biophysical indices; phenological stages; monitoring maize crop; Mediterranean agroecosystems
UAV-based tracking of floating wood during a flood 
Authors: Aarnink Janbert , Rouge Florent , Fornari Aldo , Ruiz-Villanueva Virginia
Published: March 2024

Floods in mountain rivers cause significant geomorphic changes and may entrain and transport large quantities of sediment and wood (uprooted trees). Although large wood contributes to healthy river ecosystems by providing and forming habitats for various species, it can also pose additional risks. In particular, the wood can block critical infrastructure. Governed by its density, the buoyancy of wood allows it to float and generally move at a velocity similar to the river flow. However, wood movement is complex due to interactions with the flow and the influence of turbulence and drag forces. Moreover, contact with other wood pieces can alter the forces on the floating wood. Observations of wood transport during floods are very rare, and this study aims to address this by monitoring the motion of wood during large-scale experimental floods in the Spöl River. 

The Spöl River, partially situated in the Swiss National Park, is controlled by two upstream dams, the Punt dal Gal and Ova Spin. As part of a restoration project, the company responsible for the dams releases environmental floods annually. This study monitored the movement of floating wood pieces entrained during these releases using a combination of methods. 

During the flood in June 2023, three drones were flown simultaneously. Each drone flew a maximum of 15 minutes, which was done five times between 09:30 and 11:45 in the morning. Each drone captured 24 frames per second with a resolution of 3840x2160 pixels. At an average height of 60 meters, this resulted in an average pixel size of 2.3 centimetres. Also, 6 topographical cross-sections, distributed over the observed river section were taken before and after the flood. 

The flood caused important geomorphic changes along the riverbed. In some of the surveyed sections, erosion was significant, whereas in others, aggradation was the dominant process. The video footage included approximately 90 pieces of floating large instream wood with and average length of 3 meters. When comparing the wood movement with the cross-sections, we observed that the wood pieces did not necessarily follow the river thalweg or deepest part of the channel. Local morphology, flow velocity and turbulence played a large role in the wood trajectory. In addition, the size, trajectory and rotation of wood are being analysed and compared with the flow field and local topography. 

 

This study provides unique insights into the behaviour of individual floating wood pieces transported during a flood. The findings will be valuable for comparison with numerical models and will help improving our understanding of large wood dynamics in rivers. 

 

This work is funded by the Swiss National Science Foundation project PCEFP2_186963, and supported by the University of Lausanne, the Swiss Academy of Sciences, the Swiss National Park, and the Engadiner Kraftwerke.
A Freshwater Conservation project: A Joint initiative between academia, environmental associations and companies.
Authors: Polvani Alessio , Boldrini Amedeo , Galgani Luisa , Loiselle Steven Arthur
Published: March 2024

Citizen science involves the participation of the public in research projects to enhance scientific knowledge. This kind of activities could bring advantages on the scientific, societal, educational and policy making levels. In the last decade, the breakout of citizen science has raised awareness across all segments of society. Major companies have begun actively participating in public participatory monitoring projects. In this case study, the University of Siena, Legambiente, and the Prada Group joined forces to support a freshwater monitoring project in an industrial area. The monitoring is conducted using the FreshWater Watch methodology, a well-established and scientifically validated approach used by citizens worldwide. This approach is based on visual observations and on the analysis of target freshwater parameters like nutrients and turbidity. Additionally, samples are also taken for ICP-MS analysis to provide a spatial coverage of metals presence in freshwaters. The project, started in October 2023, has so far proven successful in engaging stakeholders from environmental associations and workers of a renowned fashion brand, thus already providing valuable data from freshwater bodies in an industrial and urbanized area. The surveys, which will last for a year at least, are mostly conducted in the Valdarno region (Tuscany, Italy) on the Arno River and its tributaries and the data collected can be potentially used to support environmental agencies monitoring strategies.This talk will present analytical methods and results from the surveys up to now (> 100), and will discuss how the data collected are not only scientifically useful, but also demonstrate an important societal impact of the project and an active stewardship of aquatic ecosystems by the participating stakeholders.
Generation of High Resolution Seismic Catalog Associated With the Production Phase 2021 - 2022 at the Balmatt Geothermal Site
Authors: Gautam Rachit , Kinscher Jannes L. , Schmittbuhl Jean , Broothaers Matsen , Laenen Ben
Published: March 2024

The Balmatt geothermal doublet, developed and managed by VITO (Flemisch Institute of Technological Research), targets the fractured Lower Carboniferous Limestone reservoir in the Campine Basin at the depth of 3000 m to 4000 m. The development of the project started in 2015 and the operation began in 2018. The geothermal plant consists of two active wells, one injection well and one production well. The geothermal production had to be suspended after the occurrence of a stronger ML 2.2 event on the 23rd of June 2019 which triggered a red alert status on the local traffic light system (TLS). Production was then resumed in April 2021, following an extension of the seismic monitoring network and an update of the TLS. Activities were suspended again in November 2022 after another strong ML 2.1 event was induced. Thanks to the network extension, current investigations aim at understanding in detail the main structural features (active faults) and hydromechanical processes involved in the generation of such larger events which will contribute to improving seismic forecast possibilities for future monitoring operations. Here we present insights into ongoing data processing to create a high resolution unbiased (complete) seismic catalog providing the basis for future interpretation of the spatio-temporal and energetic behavior of seismicity towards different production settings. Our current work focuses in particular on the development of an automatic detection routine based on continuous data of the deep borehole sensor (installed at the depth of 2052 m) by combining a machine learning based automatic events detection algorithm and template matching method. The events detection in the continuous data is complicated by the periodic malfunctioning of the sensor and the presence of aseismic noise which leads to the large number of false events detection. To address this issue and to minimize the number of false detections, we employ frequency and amplitude analysis of the seismic data. Secondly we analyze source attributes of the detected events which involve source mechanism inversion and source parameter determination as well as clustering analysis and constraining source location for noisy small magnitude events. Further more the comparison between the production data (injection pressure, temperature, volume etc.) with the results from the seismic analysis will provide us with better constrain on the hydromechanical characteristics of the reservoir and the relation between the geothermal operations and seismicity at Balmatt geothermal site. 
Magma Emplacement during active rifting in the upper crust: kinematics and petrology of diabase and host rocks
Authors: B. Khater Bernardo , S. Schmitt Renata , L. C. Pires Gustavo , F. Palmeira Alessandro
Published: March 2024

During active rifting, whenever magmatism is present, magma emplacement on the upper crust is usually controlled by brittle structures reactivating an inherited tectonic fabric. In the southeastern Brazilian margin, a Cretaceous NE-SW tholeiitic dyke swarm follows the trend of the Neoproterozoic Ribeira Belt. However, in the coastal area of Rio de Janeiro, it crosscuts orthogonally the Paleoproterozoic orthogneisses of the Cabo Frio Tectonic Domain. In order to investigate how these South Atlantic rift structures formed orthogonally to the inherited host fabric, detailed structural analysis on two key areas was performed, using geological mapping with high-resolution drone images, analyzing the relation of brittle structures, diabase dykes and host rocks. The main set of faults and fractures is oriented parallel to the NE-SW diabase dykes. Dykes bifurcate or change direction abruptly following faults and fractures. Three paleostresses regimes were characterized: (1) a strike-slip transtension with NNE-SSW and NE-SW strike-slip faults; (2) an extensional transtension with oblique NNE-SSW and ENE-WSW faults; and (3) a pure extension with NNE-SSW and ENE-WSW normal faults. The tholeiitic dykes were emplaced during phases 2 and 3 continuously. Syn-kinematic secondary minerals formed on the cataclasites and the host rocks by fluid interaction. Calcite, epidote, chlorite and iron oxide compose a low-grade metamorphism of Ca-, Fe- and Mg- assemblage. These minerals also registered different phases of deformation during paleostresses regimes, with crystallization/precipitation facilitated by thermal injection of the tholeiitic magmas. Increase in permeability of the host rocks by formation of faults and fractures also contributes for the fluid migration, thus contributing with hydrothermal alteration on the upper crust. These mineral reactions also corroborated with the weakening of the continental crust, allied with the increase of dilatant slip surfaces. The combination of these tectonic and hydrothermal processes enabled the emplacement of the NE-SW Serra do Mar Dyke Swarm into the Cabo Frio Tectonic Domain, disregarding the NW-SE inherited tectonic fabric.
Triple oxygen isotopes in Atacama Desert waters since the late Miocene
Authors: Staubwasser Michael , Voigt Claudia , Herwartz Daniel , Münker Carsten , Chong Guillermo
Published: March 2024

Utilizing H and triple O isotopes, the main hydrologic variables from the Craig-Gordon model (CGM) of isotope evaporation from a lake, i.e. inflow composition (Ri), the atmosphere’s vapor composition (Rv), and relative humidity (hr) can now be accurately constrained by measurements from differently evaporated subset lakes within the basin, if they fall on a single isotope evaporation trajectory in a diagram of 17O-excess or d-excess over δ18O. We demonstrate here, that this approach can be applied also to paleo-lakes by sampling subsets of lacustrine hydrous mineral deposits - e.g. gypsum (CaSO4 • 2H2O) – from the same geologic unit representing a narrowly constrained interval of time. This allows for the reconstruction of the above variables for the past. We conducted a proof-of-concept study in the Atacama Desert on modern and U-Pb dated paleo-gypsum lacustrine deposits. We tested the principles of the above approach on gypsum and lake water from the present-day Salar de Llamara. We verified signal preservation in a 1.8 Ma old – Ri constrained – marine lagoon gypsum outcrop situated on the tectonically uplifted Mejillones Peninsula that has been exposed to meteoric water for the last ~1 Ma. Finally, we applied the method to a 9 Ma old gypsum outcrop from the paleo-lake system of Tilliviche, which existed during the late Miocene / early Pliocene between ~ 11 Ma and 5 Ma. The CGM is applied to nine sub-samples with a ~ +13 to -10 per meg range in 17O-excess (~ +15 to -16 ‰ in d-excess). The model yields a paleo-Ri equal within model uncertainty to the present-day water flowing down Tilliviche ravine with a δ18O ~ -9 ‰ reflecting its high altitude source in the Andes. Paleo-Rv has a δ18O ~ -20 ‰, which is ~ 5 ‰ lower than the present-day atmosphere. Average modelled annual paleo-hr is 66 % (44 to 84 % range), which is considerably more humid than at present (30 to 40 %). The data suggests that rainfall in the late Miocene Atacama Desert had an annual distribution equal to the present time and was likely as scarce. The more depleted past vapor composition can plausibly be explained only by higher subtropical rain-out prior to moisture advection into the desert. The higher paleo-hr implies a much lower late Miocene evaporation rate, and must have been the prime cause of the lake’s existence. Thus, the late Miocene Atacama was likely already hyper-arid in terms of rainfall, but its atmosphere was more humid and less evaporative. The desert’s hyper aridity trend since the late Miocene fits with the global subtropical aridity trend beginning ~ 8 Ma ago and widely recorded by the expansion of drought-resistant C4 plants.
Marine Heatwaves in the Chesapeake Bay: Characteristics, Subsurface Structure and Impact on Hypoxia
Authors: Mazzini Piero , Shunk Nathan , Pianca Cassia , Walter Ryan
Published: March 2024

Marine Heatwaves (MHWs) are prolonged events of anomalously warm sea water temperature, and have major detrimental effects to marine ecosystems and the world's economy. Thanks to satellite remote sensing of sea surface temperature, significant advances have been made regarding the characterization and impact of MHWs on global scales, however, these data are typically inadequate to resolve most estuarine environments with complex shorelines and reduced spatial scales. In our work we analyzed a novel data set with over three decades of in situ surface and subsurface temperature records to investigate MHWs in the largest estuary in the US: the Chesapeake Bay. Our major findings will be presented in detail, including MHW characteristics in the Bay, their trends, subsurface structure and impact on Bay hypoxia. Projections of trends found in our work suggest that by the end of the century the Chesapeake Bay will reach a semi-permanent MHW state, when extreme temperatures will be present over half of the year, and thus could have devastating impacts to the bay ecosystem and regional economy. Improving our basic understanding of MHWs, their trends and impact on hypoxia in the Chesapeake Bay is necessary to guide management decisions in this valuable environment.
Semantic and spatial Proximity Modeling of Equitable Sustainability in Proctor Creek, Atlanta: Merging Environmental Justice and Sustainable Development
Authors: Davarpanah Armita , Shafiei Fatemeh , Jelks Na'Taki
Published: March 2024

This study employs spatial and semantic modeling to formally specify the intersection of environmental concerns and social justice, focusing on the unequal impact of environmental hazards on the economically disadvantaged people living in the Proctor Creek watershed within the Atlanta Metropolitan area. Our 'Public Health-Urban-Socio-economic-Environmental Justice' (PUSH-EJ) ontology formally integrates environmental justice indices and all concepts from the EPA’s EJScreen, such as Environmental Indicator, Demographic Indicator, EJ Index, Particulate Matter, Risk, and Proximity to hazardous sites. PUSH-EJ also formalizes the National Air Toxics Assessment (NATA)’s Air Toxics Cancer Risk, Air Toxics Respiratory Hazard Index, and Diesel Particulate Matter. The modeled environmental indicators include levels of ozone, particulate matter 2.5 (micrometer or smaller-sized particles), and lead paint (for houses built before 1960) in the air, count of underground leaking storage tanks, and count and proximity to wastewater discharge areas. The ontology also models proximity of housing units to waste and hazardous chemical facilities or sites related to National Priorities List (NPL) Superfund Program, Risk Management Plan (RMP) sites, Treatment, Storage, and Disposal Facilities (TSDFs), and Traffic volume. Environmental, demographic, and socioeconomic indicators are mapped to the objectives of UN SDGs 1, 3, 4, 5, 8, and 10, bridging the gap between environmental justice, public health, urban dynamics, and socio-economic aspects. Our analysis of Proctor Creek's socioeconomic indicators reveals a combined Demographic Index of 73%, driven by Low Income (61%) and People of Color (90%). These findings indicate that Proctor Creek exhibits the lowest scores across all categories when compared to other regions in Georgia, EPA Region 4, and the nation. Our results call for minimizing contamination in the Proctor Creek area and uplifting socioeconomic conditions by the authorities responsible for the watershed. Our spatial analysis highlights urgent priorities in the Proctor Creek area, for the management of air toxic sources, emissions, and addressing proximity issues linked to environmental pollutants from hazardous waste sites, lead paint, and traffic.
Influence of horizontal model resolution on the horizontal scale of extreme precipitation events
Authors: Tandon Neil , Ali Anas
Published: March 2024

A fundamental characteristic of extreme precipitation events (EPEs) is the horizontal scale of the associated vertical motions, called “extreme ascent.” This horizontal scale can influence the intensity of an EPE through its effect on the temporal and spatial scales of an EPE as well as its effect on the strength of convective feedbacks. Thus, to have confidence in future projections of extreme precipitation, the horizontal scale of extreme ascent and EPEs in GCMs should be evaluated. Analyzing daily output from 27 models participating in the Coupled Model Intercomparison Project phase 6 (CMIP6), including 13 models participating in the High Resolution MIP (HighResMIP), we computed the horizontal scales of EPEs and extreme ascent for annual maximum EPEs during 1981-2000. We found that the horizontal scale of both EPEs and extreme ascent are resolution dependent, and the horizontal scales decrease as the horizontal model resolution increases. Further analysis reveals that this resolution-dependence is due to the fact that the precipitation during the EPEs is almost entirely resolved (rather than parameterized) precipitation. However, the EPEs are not simply grid-box storms and analysis of the horizontal scales of geopotential anomalies suggests that the large-scale dynamics in GCMs is not resolution dependent. Thus, the dominance of resolved precipitation during EPEs is more likely due to convection on the model grid or formation of strong fronts, and additional work is needed to explore these possibilities further and find a solution for the resolution dependence. This work is currently undergoing revision for consideration by Journal of Geophysical Research-Atmospheres.
Tailored accelerometer calibration by POD for thermospheric density computation with GRACE and GRACE-FO
Authors: Wöske Florian , Rievers Benny , Huckfeldt Moritz
Published: March 2024

The density of the upper atmosphere can be determined by orbit and accelerometer data from low Earth orbit satellites. Especially the accelerometers of geodetic satellites, measuring the non-gravitational accelerations acting on them are a very viable observation.The density estimation is mainly based on three separate disciplines, which are: (1) Precise radiative non-gravitational force modelling, (3) Modelling of the interaction between the rarefied atmospheric gases and the satellite, i.e. modelling of drag coefficients, and (3) the calibration of the accelerometer data by dynamic Precise Orbit Determination (POD). This contribution focuses mainly on the last point. Nevertheless, we also validate the modelled radiative accelerations and use them as reference for the calibration results.The accelerometers of all geodetic satellites are affected by a drifting bias and scale factors unequal to one. Therefore a calibration of the data is indispensable. Usually time dependent bias and scale factors are estimated. For standard POD or Gravity Field Recovery (GFR) these parameters are estimated together with empiric and other model parameters. In both cases, the estimated accelerometer calibration parameters are not of major interest, but improve the orbit fit or gravitational field coefficients. The used parametrizations and weighting strategies of the observation data, do not give realistic or physical accelerometer calibration results because parameters are not sensitive and effects are absorbed or smeared into other parameters and models. This is unsatisfying, especially for the anticipated use for the density determination.In this contribution we use dynamic POD and investigate different parametrization strategies tailored for a physical accelerometer calibration. We investigated the effect of constraining the accelerometer calibration parameters in that way, that a continuous calibration over all arcs is achieved, where normally each arc is treated locally separated from all other arcs. The scale factor is concurrently estimated, but over a longer batch of arcs. We varied the length between one day and years. Furthermore, different calibration equations, different observation data and combinations (kinematic positions, science orbit data, inter-satellite ranging), weighting strategies, initial parameters and pre-processing of the accelerometer data is investigated. The validation of the results is not easy, because usual metrics like post-fit residuals do not reflect the quality of the accelerometer calibration. We introduce a validation approach using the modelled non-gravitational forces and also show the influence of the different calibration options on the resulting density or drag acceleration.All results and data for the whole GRACE and GRACE-FO missions are available on our data server (link in presentation/ uploaded material). 
Lake organic and inorganic carbon cycle decoupling in response to historical watershed activities in Yunnan, China
Authors: Hillman Aubrey , Bain Daniel , Abbott Mark
Published: March 2024

As anthropogenic impacts to both the climate system and freshwater resources continue unabated and are expected to intensify in coming decades, an increasing number of lakes will experience carbon cycle perturbations. Lakes that have been experiencing such perturbations for millennia can clarify the nature and severity of carbon cycle disturbances as well as recoveries. In lakes with authigenic carbonate material, the use of both inorganic and organic carbon isotopes to detect the decoupling of the inorganic and organic carbon cycles has been underutilized. We summarize here the application of these methods to three lakes in Yunnan, China, which have been impacted by human activities for the last 1,500 years.  Further we compare the results from this time period to the middle and late Holocene, both periods characterized by minimal anthropogenic influence. Decreased precipitation, increased evaporation, and changes in landscape vegetation drive changes observed in sediment carbon isotope compositions from 5,500 to 3,500 years BP. Stabilization of these factors from 3,500 to 1,500 years BP resulted in fairly consistent within-lake nutrient cycling. Following anthropogenic manipulation of lake levels after 1,500 years BP and despite differences in the magnitude of such activities, a pervasive feature in all of these lakes is the decoupling of the inorganic and organic carbon cycles, primarily driven by an influx of oxidized organic carbon from the watershed and/or the respiration of lake sediment organic matter. Carbon cycle decoupling persists into present-day for some lakes, illustrating the importance of considering historical, legacy activities.
Multi-Model Comparison of Suspended Sediment Flux in the Sagavanirktok River, Alaska. 
Authors: Langhorst Theodore , Andreadis Konstantinos , Pavelsky Tamlin
Published: March 2024

Fluvial sediment transport is an important component of the global sediment budget, yet in-situ monitoring is limited. Researchers and practitioners employ various methods to fill in these gaps, each with their own advantages and drawbacks. In this study, we compare four different models for estimating the total annual suspended solids and daily suspended sediment flux for the Sagavanirktok River in Alaska. These four models include: 1) in-situ turbidity calibration; 2) WBMsed global sediment flux estimates 3) optical remote sensing random forest model; and 4) Long-short term memory (LSTM) model trained on remote sensing and modeled inputs. We focus particularly on the summers of 2022 and 2023, when we have continuous validation data via a USGS discharge gage and turbidity sensors that we installed. We evaluate the accuracy, practicality, and shortcomings of each approach to reconstructing the total suspended sediment flux of the Sagavanirktok River. We highlight the necessity of high temporal resolution (approximately daily) for estimating suspended sediment flux in the Sag. River due to the frequency of high discharge events and variable hysteresis between discharge and sediment load. We find that, for the Sag. River, optical imagery alone does not have sufficient temporal resolution to estimate suspended sediment flux (due to orbit repeat and clouds), despite the accuracy of individual estimates. The geomorphic model, WBMsed, is not accurate enough for the unusual hydrology, but does produce daily estimates. Finally, the LSTM model shows promise in being able to bridge the temporal mismatch between satellite, in-situ, and modeled dataset. The LSTM can take advantage of daily discharge models, while incorporating the accuracy of optical satellite sediment models
 Quaternary foreland tectonics and geomorphic landscape evolution- A case study of North East Himalayan Piedmont zone, India
Authors: Biswas Mery , Raha Adrija , Das Suvashree
Published: March 2024

The Main Boundary Thrust (MBT) and Main Frontal Thrust (MFT) along the east–west direction have been reanalysed under the frame of the Jiti–Khuji Diana interfluve of the Himalayan foreland basin. This area is sharply dissected by three main streams under the Jaldhaka system, i.e. river Jiti, Khuji Diana, and Thaljhora, amongst which the Thalhjora flows from east to west and the other two rivers flow roughly from NNE (north-north-east) to SSW (south-south-west). The present research focuses on the control of active Thaljora and Chalsa fault scarps, which predominantly represent the monocline fault on the landscape deformation. This fault was propagated by the folding of two opposite limb directions, forming a synform that uplifted over time and formed river terraces by incision process. The linear and basin morphometric indices confirm the neotectonic activeness in addition to the deformed landform, which emerges as terrace and Doon-shaped valley in between Jiti fault (JF) and Thaljhora fault (TS). In the studied area, Thaljhora Fault Scarp is noted as Main Boundary Thrust (MBT) and Main Frontal Thrust has been noted near Chalsa (Kar et al. 2014). This study has deciphered the application of morphometric indices to indicate active tectonics with well-exposed landforms. The two tire river terraces and the reframed alluvial fans were caused by uplift and erosion sequences that were assembled by slope differentiation and flow/velocity alteration. The alluvial fan in a fan formation stretched southward and featured three well defined geomorphic units: lobes, mid-fan, and apex. These fans are categorised as mega fans and range in size from meso to micro.To ensure that the morphological units of the study's results are clearly understood, the results are summarised in a single graphical image. Artificially induced water flow with variable discharge (Q) has been tested in the field to establish a notion of an enlarged coverage area during the monsoon and flood season
The Geometry of Three-Dimensional River Dunes
Authors: Bodapati Sree Sai Prasad , Chandra Venu
Published: March 2024

Dunes are ubiquitous in river, marine, desert and Martian environments. The fluid flow over mobile beds results in the evolution of dunes of different sizes and shapes. The literature on dunes concentrates more on 2D dunes, whereas dunes in natural rivers tend to be more three-dimensional complex shapes. The shape of the dune has a vital role in sediment transport. Bed load transport is estimated by assuming the dune shape as a triangle, which is inconsistent with field data. The typical profile of a 2D dune consists of stoss height, stoss angle, lee height, lee angle, and brink point. In three-dimensional dunes, crest line curvature also increases the complexity along with previously mentioned parameters. In the present study, the Parana river bed survey dataset is collected online (BedformsATM download SourceForge.net). The dataset contains bed profiles of Parana river surveyed in an area of 370 m x 1028 m with a spatial resolution of 1 m in each direction. Then, the bed profiles are de-trended such that dune geometry parameters can be determined accurately. The obtained dune dimensions are compared with predicted dune dimensions from different models available in the literature. It is observed that most of the models underpredicted the dune dimensions as their equations have simple relations with flow depth. The bed elevation profiles are decomposed using Empirical Method Decomposition methods to delineate the hierarchies. Further, a single dune in the Parana river dataset is isolated, and the data is used to fit the equation for a 3D dune shape. The dune generated from the equation correlates well with the original river dune. This equation will help us analyse the influence of 3D dune geometry on the flow field. Thus, it can be concluded that there is an increased need to study the flow over 3D dunes and their implications on turbulence and sediment transport.   Keywords: River dunes, 3D dunes, Dune Shape, EMD.
Modelling channel geomorphic change from landslide sediment delivery during Typhoon Mangkhut in the Philippines
Authors: Panici Diego , Bennett Georgina , Boothroyd Richard , Abancó Clàudia , Williams Richard , Tan Fibor , Matera Mark
Published: March 2024

The Antamok River in the Philippines experienced a complex geomorphic response to Typhoon Mangkhut in September 2018, which triggered >500 landslides in the Ambalanga catchment. Landslides are known to influence channel geometry by delivering large amounts of sediment. However, the interaction between landslide sediment delivery and channel geomorphic change during extreme events is poorly understood and rarely examined in tropical settings. The study catchment also has a legacy of anthropogenic modifications, such as the presence of extensive small-scale mining and tailings storage facilities (TSFs) from large-scale mining activities.The aim of this study was to use a mapping and modelling approach to test the hypothesis that landslide sediment delivery is a major control on channel geomorphic change. To accomplish this, we have applied the multi-phase model r.avaflow to a reach along the Antamok River encompassing the highest density of landslides and where it displayed a highly dynamic channel morphology. Landslide sediment delivery and TSFs are represented within r.avaflow by digitising areas of mapped landslides, allowing sediment to be delivered into the channel as well as being transported by the flow. To account for modelling uncertainty, we also tested the influence of several key-parameters by carrying out a sensitivity analysis.Using the approach described, r.avaflow was used to simulate the effects of landslide delivery and TSFs on channel erosion and deposition during the typhoon event. Results showed a good agreement between observed and simulated channel width change. When compared with traditional methods (e.g., unit stream power), the model results were considerably more accurate and consistent with observations. Furthermore, sensitivity analysis suggested that simulations are dependent on the type of sediment and physical processes considered, whilst other parameters only had negligible effects.Overall, the model simulations suggested that the impact of landslide and TSF sequences is highly dependent on the amount of sediment delivered by landslides, and a multi-phase model such as r.avaflow is possibly one of the most appropriate tools for simulating active channel width changes. Further research using these mapping and modelling tools is needed to better understand the contribution of sediment supply on channel geomorphic change during extreme events, that are otherwise difficult to observe and model.
Regional ice flow piracy following the collapse of Midgaard Glacier in Southeast Greenland
Authors: Huiban Flora , Millan Romain , Kjeldsen Kristian , Andresen Camilla , Dømgaard Mads , Dehecq Amaury , Brunt Stephen , Khan Abbas , Mouginot Jérémie , Bjørk Anders
Published: March 2024

The collapse of Midgaard Glacier in Southeast Greenland initiated a series of dynamic changes in neighbouring catchments. Understanding the evolution of this collapse, along with the numerous flow reorganisations that have transpired, is of paramount significance. This study delves into this extended retreat and drawdown since the end of the Little Ice Age, along with multiple flow reorganisations and their ripple effects on adjacent catchments. Here, we construct a comprehensive timeline, unveiling previously undisclosed complexities in glacial history. This is the first study documenting and investigating ice flow piracy and flow reorganisation in Greenland. We underscore the vital role of comprehending long-term ice dynamics, bed topography, ice-ocean interactions, and the significance of drainage basin piracy for precise predictions and models, especially in the context of climate change's impact on Greenland's ice sheet. The transformations witnessed at Midgard Glacier triggered both large (basin-wide) and local-scale dynamic shifts, affecting the flow direction of Glacier de France, and subsequently instigating dynamical adjustments within Pourquoi-Pas Glacier. This reinforces the imperative need for an interconnected basin approach when modelling dynamic changes on the ice sheet.
 
Electric Heat Revolution: Navigating the Landscape of the Future Electricity Market
Authors: Jafaripour Lavin (Zahra) , Lyden Andrew
Published: March 2024

As the global movement towards energy system decarbonisation gains traction, electrifying heating systems will emerge as a pivotal approach to reduce carbon emissions in the residential sector. Electrification promises a substantial reduction in greenhouse gas emissions, improved energy efficiency, and enhanced integration of renewable energy sources. Furthermore, electrified heating systems offer flexibility through demand response mechanisms, contributing to grid stability and resilience.The challenges of electrifying heating systems are multifaceted, encompassing technical, economic, and societal dimensions. Technical challenges include addressing the intermittency of renewable energy sources, upgrading existing infrastructure, and ensuring grid reliability. Economic challenges involve the costs associated with technology adoption, potential impacts on energy bills, and financial considerations for both consumers and utilities. Societal challenges entail managing the transition for workers in traditional heating industries, addressing potential energy poverty concerns, and fostering public acceptance. Alongside these challenges, the transition to electrified heating has the potential to substantially influence the optimal design of the electricity market. The increased demand for electricity, particularly during peak heating periods, necessitates strategic modifications to market structure and operational frameworks. While there are numerous advantages and improvements associated with this transition, a comprehensive understanding of the impacts of the electrification of heating within the electricity market is currently lacking.The main goal of this paper is to assess the advantages and challenges associated with electrifying heating systems, and potential changes that will take place in the electricity market as a consequence of this electrification. Through an extensive literature review, this paper seeks to contribute valuable insights for the development of strategies and policies aimed at fostering a sustainable and resilient electricity market, particularly in the evolving landscape of heating technologies.This study lays the groundwork for additional investigation into the complex relationship between heating electrification and the changing electricity market, providing important information for sustainable energy transitions. 