bluuebunny/crossref_metadata_2025 huggingface dataset:
Méditerranée 2000: Nurturing climate & ocean awareness
Authors: Promduangsri Pimnutcha , Promduangsri Pariphat , Bellanger Estelle
Published: March 2024

Humans have been suffering increasingly from the escalating impacts of climate and ocean change.  Well known examples are droughts, flooding, wildfires, acidification, heatwaves, sea-level rise, extreme storms and biodiversity loss.  If global average temperature rises by more than 1.5°C above pre-industrial levels, multiple climate tipping points will be triggered, and indeed, some already are.  This is and will be devastating for people around the world, especially those in coastal areas.  Thus, the need for immediate and informed action has become urgent.This presentation will outline some of the many concrete, local actions in the area of climate and ocean, undertaken by Méditerranée 2000 (Med2000), an environmental association in the South of France.  Since 1989, the association has committed its efforts and educational programs to promoting sustainable development.  Each year, the association educates more than 25,000 young people and adults, led by a team of ten specialized speakers.  Med2000’s initiatives include awareness campaigns about climate and ocean change, hands-on educational activities in local schools and events for the general public.
Shallow tremors in the northern sulawesi subduction zone
Authors: Jiang Chenghao , Zhang Jian , Hao Tianyao
Published: March 2024

Tectonic tremors (TTs), composed of a swarm of low-frequency earthquakes (LFEs), constitute a type of slow earthquakes characterized by a lack of high-frequency energy. Previous studies have suggested that slow earthquakes, which usually occur near the megathrust earthquake rupture zones, are crucial for deepening our understanding of seismic activity. The Northern Sulawesi subduction zone (NSSZ) is situated at the convergence of the Eurasian, Australian, and Philippine Sea plates, experiencing frequent earthquakes that may trigger local tsunamis due to the complex tectonic setting. Until now, the lack of shallow observations has limited the understanding of the shallow tectonic structure beneath the NSSZ. We observe episodic shallow TTs using 8 Ocean Bottom Seismometers (OBS) deployed near the NSSZ, indicating the presence of stable sliding near the subduction boundary. Our research results reveal that the locations of shallow TTs align with the boundary of the weakly coupled plate interface where the relative Coulomb stress is weaker. Additionally, we discover that the sedimentary environment in the shallow subduction zone and the dehydration of serpentinite within the plates provide favorable conditions for high pore fluid pressure, thereby promoting the occurrence of shallow TTs. Furthermore, we try to establish a connection between deep earthquakes and shallow TTs, exploring the possibility of deep-seated stress propagating from the deep crust to the shallow seismic zone through faults or plate boundaries.
Flow Structures Near the Zero-Degree Confluent Open Channels
Authors: Ansari Mohd Faisal , Ahmad Zulfequar
Published: March 2024

The confluence of rivers/channels is an essential node of the fluvial system. Flow structures near the confluence of channels are complex and need to be studied. The discharge ratio in the channels and confluence angle are important parameters affecting the flow structures near the confluence. The main objective of this study is to investigate the flow structures for different discharge ratios in the channels. Detached Eddy Simulation (DES) was utilized to study the flow structures near the confluence of the channels. Vortical structures were observed shifting downstream of the confluence point with a decrease in the discharge ratio (discharge in primary channel/ total discharge).
Keywords: Confluence; Detached Eddy Simulation; Flow Structures, Discharge ratio
A favorable sub-Neptune target for JWST and Ariel observations: TOI 1759 b
Authors: Lavvas Panayotis , Coustenis Athena , Encrenaz Therese , Charnay Benjamin , Bézard Bruno , Drossart Pierre , Gressier Amélie , Panek Emilie , Edwards Billy , Ollivier Marc , Molaverdikhani Karan , Venot Olivia , Bardet Deborah , Lagage Pierre-Olivier , Tinetti Giovanna
Published: March 2024

Following the extensive exploration of hot and warm exoplanets over the past two decades, recent improvements in instrumental techniques, from ground and space, have allowed the detection of “temperate” exoplanets, with equilibrium temperatures ranging between 300 and 500 K. Opening this new research field will not only enlarge our comprehension of the various physical properties of exoplanets, but also reduce the comprehension gap between these objects and the planets of our solar system, and provide a key step towards the study of habitable exoplanets. Over the past few years, we have started a program [1, 2] for identifying temperate exoplanets, which would be observable with the Ariel mission in the spectroscopic mode (Tier 2 mode). Using the TESS database and analyzing the observability of the candidates with Ariel, we have selected a list of 15 targets (a gas giant, a few big Neptunes and several super-Earths/sub-Neptunes) for which spectroscopic observations with Ariel would allow a characterization of their atmosphere and possibly an identification of the main atmospheric absorbers [3]. Among this list, the sub-Neptune TOI-1759 b appears as a favorable candidate. With a radius of about 3 earth radii and a mass of about 10 earth masses, TOI-1759 b is most likely a hydrogen-rich planet orbiting a M0.0 star located at 40 pc with a revolution period of 19 days. We have calculated the thermal structure, dis-equilibrium composition and size distribution of cloud and haze particles in its atmosphere using a model that couples self-consistently the involved physical and chemical processes [4]. Cloud nucleation rates reach significant values near a pressure level of 0.35 bar, where the condensing gas species (KCl, NaCl and Zn) approach their saturation limit. We have calculated the infrared synthetic spectrum of TOI-1759 b from the visible up to 20 μm for different metallicities and different haze and cloud conditions. Feasibility studies [5] suggest that information could be retrieved about the target’s atmosphere with 16 primary transit observations with Ariel (which could be achieved over a time range of less than a year), or a single primary transit observation with the JWST. [1] Encrenaz, T.  et al., Exp. Astr. 46, 31 (2018) [2] Encrenaz, T. et al.,  Exp. Astr. 53, 375 (2022).[3] Encrenaz, T. et al. Poster presented at the EGU General Assembly, Vienna, April 2023.[4] Arfaux & Lavvas, MNRAS, 515, 4753 (2022).[5] Tinetti et al., Exp.Astr. 46, 135 (2018).
Parameter estimation of heterogeneous field in basin scale based on signal analysis and river stage tomography
Authors: Wang Bo-Tsen , Chang Chia-Hao , Tsai Jui-Pin
Published: March 2024

Understanding the spatial distribution of the aquifer parameters is crucial to evaluating the groundwater resources on a basin scale. River stage tomography (RST) is one of the potential methods to estimate the aquifer parameter fields. Utilizing the head variations caused by the river stage to conduct RST is essential to delineate the regional aquifer's spatial features successfully. However, the two external stimuli of the aquifer system, rainfall and river stage, are usually highly correlated, resulting in mixed features in the head observations, which may cause unreasonable estimates of parameter fields. Thus, separating the head variations sourced from rainfall and river stage is essential to developing the reference heads for RST. To solve this issue, we propose a systematic approach to extracting and reconstructing the head variations of river features from the original head observations during the flood periods and conducting RST. We utilized a real case study to examine the developed method. This study used the groundwater level data, rainfall data, and river stage data in the Zhuoshui River alluvial fan in 2006. The hydraulic diffusivity (D) values of five observation wells were used as the reference for parameter estimation. The results show that the RMSE of the D value is 0.027 (m2/s). The other three observation wells were selected for validation purposes, and the derived RMSE is 0.85(m2/s). The low RMSE reveals that the estimated D field can capture the characteristics of the regional aquifer. The results also indicate that the estimated D values derived from the developed method are consistent with the sampled D values from the pumping tests in the calibration and validation processes in the real case study. The results demonstrate that the proposed method can successfully extract and reconstruct the head variations of river features from the original head observations and can delineate the features of the regional parameter field. The proposed method can benefit RST studies and provide an alternative mixed-feature signal decomposition and reconstruction method.
Geochemistry of Banded Iron Formations (BIFs) from the Central Bundelkhand Craton, India: Implication for depositional setting
Authors: Malviya Vivek Prakash , Thomas Harel , Verma Sanjeet Kumar , Shukla Mahendra , Dora Muduru Lachhana , Kumar Alok
Published: March 2024

The depositional environment of the Banded Iron Formations (BIFs) is highly controversial. The BIFs are type of chemical precipitates characterized by presence of alternating layers of iron and silica-rich. Paleo-Mesoarchean BIFs of the Central Bundelkhand Greenstone Belt (Babina-Mauranipur-Mahoba) occur along with the E–W trending of the Bundelkhand Tectonic Zone (BTZ) gives us opportunity to study the depositional environment during Archean Eon. The lithological association of BIFs in the Babina and Mauranipur areas consists of pillowed basic–ultrabasic volcanics and metasediments whereas the Mahoba´s BIFs and quartzite occur within basic volcanics. The bulk geochemical composition of BIFs shows the high content of FeOt with an average of 51.57 wt. %. The Babina´s BIFs show relatively lower concentration of V, Cr and Co in comparison to the Mauranipur and Mahoba. The significant negative Ce anomaly implies the signature of a deep marine source of the Bundelkhand BIFs. The samples from Babina show less Y/Ho ratios, along with lack of relativelyhigh Zr, Th, and Hf suggest that terrestrial material input was insignificantor very less during BIFs precipitation. Most of the BIFs from the Mauranipur and Mahoba show intermediate Y/Ho ratio suggesting chemical precipitation of BIFs from a mixture of seawater and high-temperature hydrothermal fluids generated from a back-arc spreading centre. The geochemical characteristics indicate that these BIFs are formed by volcanogenic hydrothermal activity in aback-arc tectonic setting. The Rare Earth Elements (REE) patterns suggest the role of high-T hydrothermal fluid for the deposition of BIFs in the Babina and Mauranipur greenstone belts whereas low-T hydrothermal fluid is responsible for the Mahoba greenstone belt deposition. Their geochemical variation also suggests the shallowing of the proto-basin from the Babina (west) to Mahoba (east).
In situ nanoscale insights on magma viscosity and explosive eruptions
Authors: Valdivia Pedro , Zandonà Alessio , Löschmann Jessica , Bondar Dmitry , Genevois Cécile , Canizarès Aurélien , Miyajima Nobuyoshi , Kurnosov Alexander , Boffa Ballaran Tiziana , Di Fiore Fabrizio , Vona Alessandro , Romano Claudia , Allix Mathieu , Deubener Joachim , Di Genova Danilo
Published: March 2024

Explosive volcanic eruptions pose significant threats to populated areas by injecting substantial amounts of gas and ash into the atmosphere. These events, resulting from magma fragmentation, are triggered by factors such as limited bubble expansion and relatively high strain rates during ascent, predominantly controlled by chemical composition. Less evolved melts, like andesites and basalts, present challenges in achieving fragmentation conditions due to their inherently low viscosities. Despite this, explosive activity of these magmas occurs. Recent studies highlight the role of Fe-Ti-oxide nanocrystals (nanolites) in increasing viscosity during laboratory measurements. Interestingly, nanolites have been found in natural volcanic products erupted during explosive events. However, the mechanisms and the extent to which nanolite formation affects magma viscosity remain a subject of ongoing debate. Here, we present the first in situ imaging observation of nanolite formation in andesitic melt and thoroughly quantify the impact on melt viscosity. To establish a robust point of comparison, we develop multiple novel viscosity models exclusively using viscosity data from nanolite-free samples. Our findings reveal that above the glass transition temperature, iron oxidation and nanocrystallization readily occur, inducing structural heterogeneities in the nanoscale. The precipitation of magnetite nanocrystals induces a heterogeneous distribution of elements in the residual melt, generating a relatively SiO2-enriched matrix and Al-enriched shells around the nanolites. This phenomenon results in a substantial, up to 30-fold, surge in magma viscosity at eruptive temperatures. This noteworthy increase in magma viscosity has profound implications for the physical properties of andesitic plugs and domes and could play a critical role in driving the magma towards fragmentation during eruption.
Tin mineralization in post-magmatic processes: a case of post-magmatic activity in the Szklarska Poręba Huta quarry, Lower Silesia, SW Poland 
Authors: Mil Karolina , Gołębiowska Bożena , Włodek Adam , Pieczka Adam
Published: March 2024

The Karkonosze granite (~320–312 Ma) is interpreted as a syn-collisional to magmatic arc intrusion. It is known for distinct symptoms of post-magmatic activity, including formation of intragranitic pegmatites observed in Szklarska Poręba quarry with overprinted W–Sn–Mo–Bi hydrothermal mineralization (e.g., Kozłowski et al., 1978; Pieczka & Gołębiowska, 2012).Tin mineralization in the granite quarry at Szklarska Poreba is represented by cassiterite (Karwowski et al., 1972), Sn-rich titanite, malayaite, stokesite, and rare tin sorosilicates – kristiansenite, kozłowskiite and silesiaite (Evans et al., 2008;  Pieczka et al., 2022, 2023) The presence of all the above-mentioned mineral phases was confirmed by chemical microanalysis using the electron probe microanalyzer JEOL SuperProbe JXA-8230 and structure refinement. Cassiterite was recognized in an association mainly with scheelite, molybdenite, wolframite, chalcopyrite, and pyrite. These minerals crystallized from high-temperature aqueous fluids, subsequently followed by sulphide-rich stage (Karwowski et al., 1973). Sn-rich titanite, forming an isomorphic series with malayaite, CaTi[SiO4]O–CaSn[SiO4]O, shows chemical heterogeneity, with a maximum SnO2 content up to 15.88 wt% (32 mol% Sn end-member), and elevated Nb2O5 (up to 9.85 wt%), Ta2O5 (up to 7.88 wt%), and Sc2O3 (up to 1.90 wt%). Malayaite is close to the pure Sn end-member, it contains up to 97 mol% Sn end-member with minor Fe, Nb, Ta contents. Stokesite, CaSnSi3O9·2H2O, occurs as a rim grown around the outermost parts of Sn-rich titanite crystals, veinlets cutting cassiterite, and in direct contact with fluorite. Its crystals were also observed on surfaces or within fractures in bismuthinite.The initial source of Sn was related to the final stage of pneumatolytic processes, in the granitic complex with successive development during hydrothermal activity. Fluid inclusion studies indicate that cassiterite crystalized at temperatures of 515–470ºC (Kozłowski et al., 2002).The precipitation of Sn-rich titanite was likely initiated under elevated metal activities at slightly lower temperatures and high oxygen fugacity.Stokesite, representing the final stage of the Sn assemblage, slowly crystallized in free spaces, was found in a direct contact with fluorite, which homogenization temperature in the Szklarska Poręba assemblage was estimated at 159-172 oC (Kozłowski & Matyszczak, 2022). Therefore, stokesite and fluorite may have formed during the same stage of hydrothermal processes. Since no alterations had been observed on the cassiterite grains, a secondary source of tin for later Sn-rich minerals was excluded. 
Solar activity variations in the composition of the low- and mid-latitude ionosphere-thermosphere system
Authors: Vaishnav Rajesh , Jacobi Christoph , Schmölter Erik , Dühnen Hanna , Codrescu Mihail
Published: March 2024

Having a comprehensive understanding of the ionosphere's irregular behavior and its response to solar activity is crucial for satellite communication and navigation applications. The sun's extreme ultraviolet (EUV) and ultraviolet (UV) radiation are the primary sources of energy for the Earth's thermosphere and ionosphere (TI). To understand the global response of TI parameters (e.g., O/N2, and the peak electron density (Nmax)) to changes in solar irradiance, various data have been used. These include the Global-Scale Observations of the Limb and Disk (GOLD) ultraviolet imaging spectrograph, solar radio flux F10.7, predictions from the Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) model, and International Global Navigation Satellite System Service total electron content maps (TEC). The comparison between these measurements shows that the CTIPe model successfully reproduces the behavior of the low- and mid-latitude ionosphere during both low and high solar activity.The study also investigated the delayed ionospheric TEC response against solar flux variations within the 27-day solar modulation. It was observed that the delay is less than one day, which was also confirmed in model simulations. Furthermore, the model simulations showed that the ionospheric time delay is significantly affected by various physical processes such as diffusion, photodissociation, solar and geomagnetic activities, and wave dynamics.
Climatology and Trends in Concurrent Temperature Extremes in the Global Extratropics
Authors: Segalini Antonio , Messori Gabriele , Ramos Alexandre M.
Published: March 2024

Simultaneous occurrences of multiple heatwaves or cold spells in remote geographical regions have drawn considerable attention in the literature, due to their potentially far-reaching impacts. These include widespread crop failures, increased mortality, wildfires, power supply disruptions and more. We introduce a flexible toolbox to identify and study such concurrent temperature extremes, with adjustable parameters that different users can tailor to their specific needs and impacts of interest. We then use the toolbox to present a climatological analysis of concurrent heatwaves and cold spells in the global midlatitudes. Specific geographical areas, such as Western Russia, Central Europe, Southwestern Eurasia and Western North America, emerge as hotspots for concurrent temperature extremes. Concurrent heatwaves are becoming more frequent, longer-lasting and more extended in the Northern Hemisphere, while the opposite holds for concurrent cold spells. Concurrent heatwaves in the Southern Hemisphere are comparatively rare. However, their sharp increase in recent decades means that they are becoming an emerging hazard in the Southern midlatitudes. Notably, trends in concurrent temperature extremes are significantly stronger than the corresponding trends in all temperature extremes. This suggests that concurrent heatwaves will be an increasingly important climatic hazard in both absolute and relative terms in a future, warmer, climate.
25 years of precipitation isotopic composition across the USA: Assessment of non-linearities associated with moisture source dynamics and storm track variations in the Community Earth System Model
Authors: Dar Shaakir Shabir , Macarewich Sophia , Klein Eric , Welker Jeffrey
Published: March 2024

A 25-year record from the United States Network for Isotopes in Precipitation (USNIP) using data from seventy-three sampling sites reveals the dynamic role of moisture sources and storm tracks in controlling the precipitation geochemistry at a continental scale. Our study provides a fresh perspective on processes governing the water isotope cycle beyond the classic role of temperature. We report that Climate Oscillations (COs) combine to influence synoptic climatology and atmospheric transport patterns, thereby driving spatiotemporal distribution of precipitation 18O, 2H and d-excess values. The relationship between the individual COs and the isotopic composition of precipitation is spatially, temporally, and geographically inconsistent with varying time periods of linear (positive/negative), non-linear, or no coherence. The interactions between COs drive variations in isotope fractionation associated with evaporation (moisture source dynamics) and transport (storm track pathways and degree of rainout) of moisture. These are mirrored in the spatiotemporal precipitation isotope patterns across contiguous USA and supported by airmass trajectory analysis. We use the USNIP observational dataset to validate and test process representation in the variable-resolution isotope-enabled Community Earth System Model-version 2 (VR-iCESM2) with regional grid refinement to ~12.5 km over the contiguous US. To explore the relative influences of origin, transport, and condensation of water vapor on precipitation isotope patterns, we use process-oriented water tags in the VR-iCESM2 that track physical properties at the evaporation source locations, Rayleigh rainout effect, and precipitation condensation temperature. We find the model prediction to be deficient in coastal regions which improves in the continental interior, but ‘nudging’ the model with atmospheric thermodynamic properties and grid refinement leads to an overall enhancement in model performance relative to low resolution (~100 km) iCESM simulations. Evaluating and improving water cycling processes in climate models using spatially dense, long-term observational datasets of water isotopes, such as USNIP, will improve interpretations of paleoclimate records and predictions of future changes.
Progressive development of an accretionary wedge margin from oblique thrust to strike-slip fault (Mikulov Fault, Outer Western Carpathians).
Authors: Šutjak Martin , Melichar Rostislav , Baroň Ivo , Chen Yi-Chin , Černý Jan , Dong Jia-Jiyun , Dušek Václav , Hartvich Filip , Kociánová Lenka , Nguyen Tung , Rowberry Matt , Tseng Chia-Han
Published: March 2024

The Outer Western Carpathians are fractured by several syn-thrust and post-thrust faults. One of them, the Mikulov Fault, has been studied using a combination of surface and subsurface methods. The former comprised the analysis of a LiDAR digital terrain model and aerial photographic interpretation while the latter comprised the analysis of ERT profiles and 2D seismic reflection profiles interpreted with the aid of borehole data. Paleostress analysis has also been used to understand the stress history and progressive development of the fault. By combining these methods it has been possible to define a distinct N-S directed fault zone that intersects or delineates the majority of the Jurassic limestone nappe outliers around the highlands of Pavlov Hills. This almost continuous fault zone runs for several kilometers on the Czech side of the border and extends further south into Austria. The thrusted Jurassic limestone bodies are cut by the fault zone, which tectonically crushed the limestone in its core and the cores of the secondary fault branches. The mapped pattern of the fault zone suggests branching and reattaching with the production of lenticular tectonic slices. Consequently, we interpret the fault as a prominent sinistral shear zone. This is indicated on the surface by block displacement on Svatý kopeček Hill and by the orientation of the accompanying subvertical Riedel shears with identified horizontal lineation. Subsurface kinematic indication derives from the interpretation of a prominent negative flower structure in the deep seismic profiles, just beneath the fault zone. The ERT profiles have revealed that the limestone bodies are tectonically bound by accompanying fault branches. Moreover, paleostress analysis suggest that fault zone activity can be divided into three main stages: (i) NE-SW thrust faults indicate thrusting of the Carpathian accretion wedge over the Bohemian Massif; (ii) NE-SW strike-slip faulting, during which the fault blocks moved along the faults in the direction of propagating wedge; (iii) N-S strike-slip faulting, marking the change in compression direction and transition from thrusting to a strike-slip regime. The main movement along the fault is probably of the late Miocene age and probably continues to the present day. The research was funded by the Grant Agency of the Czech Republic (GC22-24206J).
Downhole passive fiber optics temperature monitoring for improved characterization of aquifer heterogeneities
Authors: Furlanetto Davide , Camporese Matteo , Schenato Luca , Costa Leonardo , Salandin Paolo
Published: March 2024

Unconfined shallow aquifers are particularly exposed to the risk of contamination. Especially when exploited for drinking water production, for which water quality is of particular concern, careful monitoring of the physical processes and detailed characterization of the subsurface properties are crucial. Furthermore, the possible presence of heterogeneities, such as intricate networks of hydraulically conductive paleo-channels that are often inherent in alluvial aquifers, can establish preferential pathways. Consequently, monitoring activities in these complex environments pose serious challenges and raise the demand for advanced techniques and innovative approaches. In this context, recent advances have been made possible by employing Fiber Optics Distributed Temperature Sensing (FO-DTS). This technology combines the use of heat as a natural tracer with a detailed spatiotemporal resolution and has proven informative in a wide variety of applications. In this study, we applied downhole passive FO-DTS to a cluster of piezometers in a highly heterogeneous phreatic gravelly aquifer. The aquifer is exploited for irrigation and drinking water supply, and exhibits both natural and pumping-induced groundwater temperature fluctuations. Vertical transient water temperature profiles were acquired over a 1-month experiment. Borehole-dependent and depth-related features of the temperature measurements were ascribed to possible spatial structures having different hydraulic conductivity. The collected data were used to invert the three-dimensional saturated hydraulic conductivity field of a physics-based numerical model that couples flow and heat transport. Even without active heating, FO-DTS has demonstrated its ability to provide valuable insights at an unprecedentedly high resolution.
A multi-proxy paleoclimate record from a peat soil of interior Alaska: insight on mechanisms of Holocene peatland formation and landscape development 
Authors: Kielhofer Jennifer , Patton Nicholas , Baish Christopher , Thomas Elizabeth , Sion Brad
Published: March 2024

Arctic and subarctic regions are warming at an alarming rate, with consequences for permafrost degradation, greenhouse gas emission, ecosystem destabilization, and infrastructure deterioration. Despite high latitude sensitivity to modern climate change, a substantial gap remains in our understanding of high latitude environmental response to past episodes of climatic change. Peat soils, common across the high latitudes, provide a valuable archive for paleoclimate reconstruction to address this knowledge gap. Many such records exist across interior Alaska and have high potential as paleoclimate archives.Here we develop a multi-proxy paleoclimate record from a peat bog soil (Terric Hemistel) in the Delta River Valley of interior Alaska to explore mechanisms of peatland initiation and evolution. We aim to develop a comprehensive record related to the formation and evolution of this peat bog and test the hypothesis that increased moisture availability and water perching within the soil, rather than warmer temperatures, initiated peatland development. We evaluate key physical and chemical properties of organic and mineral soil materials from pedon descriptions and samples collected by horizon with depths defined according to organic matter content, bulk density, pH, carbon (C), nitrogen (N), and the carbon to nitrogen (C/N) ratio. We use radiocarbon dates to build an age-depth model and analyze stable isotopic signatures (δ13C) of bulk material for moisture and habitat changes, while also evaluating compound-specific isotopic trends (δ13C, δD) of plant waxes to track hydrological fluctuations. Finally, we perform analyses of bacterial branched glycerol dialkyl glycerol tetraethers (brGDGTs) to enable temperature reconstruction.Our preliminary chronological framework demonstrates the initiation of the peat bog during the Middle Holocene (ca. 6800 cal yr BP) with a consistent growth rate of ~0.15 mm/yr.  At the landscape scale, there is relative stability indicated by pedogenesis through the Holocene, but at the pedon scale there is a shift from concurrent aeolian deposition and mineral soil development to accumulation of organics. This shift in predominant parent material is likely due to a changing moisture regime, inferred to be the result of feedbacks between increased summer precipitation and increased soil water holding capacity. We hypothesize that brGDGTs will show relatively flat temperatures through the Holocene, following other work in the area, while C/N ratios and stable isotope data will indicate pronounced changes in moisture. This multi-proxy approach will help improve models of peatland formation and resolve debate over the response of peatlands to varying climatic conditions (e.g., drier vs. wetter). Such work is particularly important for contextualizing peatland development under ongoing and future climate change. 
The InSEEDS Model - coupling LPJmL and copan:CORE towards an integrated human-earth system model of regenerative land-system change
Authors: Breier Jannes
Published: March 2024

The Anthropocene is the current geological epoch characterized by co-evolutionary dynamics between human societies and the Earth system. Linking biogeophysical and social processes is therefore essential to understand current developments in the Earth system. Especially the agricultural sector is a key driver of land system change, biodiversity loss, soil degradation, and a major contributor to global greenhouse gas emissions. To analyse and understand the mechanisms of these interactive systems, we developed the model of Integrated Social-Ecological rEsilient lanD Systems (InSEEDS), which couples the Dynamic Global Vegetation Model LPJmL with the agent-based modeling framework copan:CORE. LPJmL simulates the biogeophysical processes of the Earth system on a global 0.5° grid, in particular the terrestrial carbon, water, and nitrogen cycle, and can model, for example, plant and crop growth or water and fertilizer consumption. Various agricultural management practices can also be modeled, such as tillage, mulching, or cover crop cultivation. copan:CORE, on the other hand, can instantiate agents that reflect the behavior of farmers, management decisions, or interactions of the social world in different regions.
We here describe this novelty of World-Earth modeling and present the first exemplary application of the coupled model system which explores potential pathways for sustainable agricultural practices to spread. In this example we compare the potential social spreading of conservation tillage practices in contrast to conventional tillage practices based on the distribution of two different farmer types in the model, so-called agent functional types.
Quantification of the Greenland ice sheet surface mass balance using high-resolution CARRA data and in-situ observations
Authors: Mülder Verena , van Tiggelen Maurice , Tijm-Reijmer Carleen
Published: March 2024

This project contributes to the understanding of the surface mass and energy balance of the Greenland ice sheet, by evaluating the accuracy of the Copernicus Arctic Regional Reanalysis (CARRA) dataset against in-situ observations collected from automatic weather stations (AWS) positioned along the K-transect on the Greenland ice sheet.  Additionally, the results are compared with the Regional Atmospheric Climate Model 2.3p2 (RACMO2.3p2), containing a spatial resolution of 11 km against CARRA’s 2.5 km horizontal resolution. This research thereby emphasizes the improvements and shortcomings of the new CARRA dataset for reproducing the near surface climatology on the Greenland ice sheet.The validated CARRA dataset is then used as forcing in a surface energy balance model, enabling the determination of the surface mass and energy balance components of the Greenland ice sheet at higher spatial resolution. The modelled surface mass balance is evaluated against in-situ measurements along the K-transect, and to other regions where in situ measurements are available. Preliminary results show that the CARRA dataset accurately reproduces radiative fluxes, such as short- and longwave radiation components, as well as turbulent fluxes, including temperature and wind gradients. These accurate representations provide updated, high-resolution gridded fields of the Greenland ice sheet’s climate, and are crucial for precise modelling of the melt and runoff dynamics of the Greenland ice sheet through the surface energy balance model.This research thereby presents an updated high-resolution depiction of the Greenland ice sheet climate and energy balance, which can be used as a foundation for future projections of the Greenland Ice Sheet in forthcoming studies.
Mechanisms of reduced mid-Holocene precipitation in arid central Asia as simulated by PMIP3/4 models
Authors: Wang Tao , Xu Hongna , Jiang Dabang , Yao Junqiang
Published: March 2024

We investigated the precipitation changes in mid-latitude arid central Asia (ACA, including Central Asia and Xinjiang) and the related mechanisms in the mid-Holocene using the output from the Paleoclimate Modelling Intercomparison Project phases 3 and 4 (PMIP3/4). The annual precipitation in ACA was decreased in the mid-Holocene compared with the pre-industrial period, consistent in direction with reconstruction records. Such change was mainly due to deficient winter and spring (December–May) precipitation in the mid-Holocene. The decrease in incoming solar radiation in the mid-Holocene winter and spring caused stronger surface and tropospheric cooling in the northern low latitudes. It reduced the meridional temperature gradient in the troposphere, thereby weakening the westerly winds and related transport of water vapor. More importantly, the cooling weakened the local water cycle in ACA. Finally, the precipitation decreased over almost all of ACA. In the mid-Holocene summer (June–August), the meridional temperature gradient and related westerly winds were also reduced. It was mainly caused by stronger surface and tropospheric warming in the northern mid- to high latitudes. The stronger warming was due to increased summer incoming solar radiation in the mid-Holocene. This process differed from that occurred in winter and spring. Therefore, the water vapor transport was weakened, and the summer precipitation was deficient in northern ACA. At the same time, strengthened descending motions contributed to the decrease in summer precipitation in most Central Asia. On the contrary, intensified ascending motions increased summer precipitation in southeastern Xinjiang. 
The nature of mesopause jumps as simulated with the nudged KMCM model
Authors: Schaefer-Rolffs Urs , Zülicke Christoph , Lübken Franz-Josef
Published: March 2024

Mesopause jumps are a phenomenon that is only observed in the southern summer MLT region. The mesopause is lifted by several kilometers within a few days and then later returns to its original altitude accompanied by strong cooling. Lidar and radar measurements indicate that these jumps are the result of a late breakdown of the polar jet, which occurs frequently in the southern hemisphere. Although the basic mechanism is known, no successful simulations of such mesopause jumps have yet been performed.In my talk, I will present a case study using the Kühlungsborn Mechanistic general Circulation Model (KMCM) in which nudging is applied. I will compare measurements of the austral summers 2010/11, 2011/12 and 2012/13 obtained with lidars and radars over the Davis station in Antarctica at 69°S with simulations performed with the KMCM. Mesopause jumps were detected in the first two summers, while no jump occurred in the last summer.In general, our simulations show that the KMCM with nudging is able to reproduce mesopause jumps. In November and December, the simulations agree quite well with the observations, and we can better understand the role of gravity waves in the mechanism of mesopause jumps. In January and February, however, the simulations seem to be too active, as the agreement with the observations is less good.
Seasonal to interannual variations of daily growth rate of Tridacna shell from Palau Island, western Pacific, and their paleoclimatic implication
Authors: Wen Hanfeng
Published: March 2024

Seasonal-interannual climate change is an important component of Earth’s climate system and has a significant impact on ecosystems and social systems. However, the scarcity of modern observational data limits our understanding of the seasonal-interannual climates in long-term timescales. The natural archives can provide information on climate change before the industrial period, but most of their temporal resolution is too low to capture the seasonal-interannual climate signals. Tridacna spp. is the largest marine bivalve, and its shell has the potential to trace climatic/environmental changes on a daily to interannual scale. In this study, we have investigated the daily growth pattern of modern Tridacna gigas shell (PL-1) from Palau based on laser scanning confocal microscopy images. The results showed that the growth pattern of PL-1 was affected by OLR primarily on the seasonal timescale. On the interannual timescale, the growth rate of the shell was modulated by ENSO through the changing OLR, SLH, and upwelling, which affect the effective solar radiation and nutrients accepted by Tridacna. The growth rate of Tridacna PL-1 is accelerated during the ENSO positive phase, and vice versa. This study indicates that the daily growth rate of Tridacna shells in equatorial regions may have the potential to reconstruct seasonal-interannual climate/environment variations.
Status of soil health after 18 years of systematic tillage
Authors: Simon Barbara , Gelybó Györgyi , Dekemati Igor , M.I. Tharwat Hanaa , Maimela Modiba Maxwell , Birkás Márta
Published: March 2024

Carbon sequestration in our soils in the form of stable, humus materials is one of the most important tasks of our time, which can be monitored by tests carried out in long-term cultivation experiments. In our research, our objective was to determine the soil physical (0-10, 10-20, 20-30 and 30-40 cm depth: bulk density, soil moisture content), chemical (0-20 cm: pH(H2O), pH(KCl), soil organic carbon) and biological properties (0-20 cm: abundance, biomass, species composition of earthworms, soil microbial respiration – SMR). Out of the six soil cultivation methods (no-till, loosening, shallow and deep cultivation, disking and ploughing), we selected three (no-till – NT; shallow cultivation – SC, and ploughing – P) for our experiment. Based on our results, we can say that there was significant difference among the treatments in bulk density in the top layer (0-10 cm) (NT > SC, P), and NT was significantly greater than P in the deeper layers (10–20, 20–30, 30–40 cm). Soil moisture content was only significantly different in the lowest examined layer (30-40 cm), ie. P > SC = NT. The soil organic carbon content (0-10cm) of the investigated treatments was the highest in NT (2.5%), followed by SC (2.4%) and P (2.0%). Soil microbial respiration was significantly greater in NT than in SC and P. The abundance and biomass of earthworms was the highest in the NT treatment (189 ind m-2, 41.26 g m-2), which was followed by SC (125 ind m-2, 36.9 g m-2) and then by P (48 ind m-2, 7.4 g m-2). Thus, NT offers beneficial habitat for earthworms and microorganisms, high SOC storage capacity, whereas the physical parameters tend to be less convenient due to soil compaction in our experiment. Therefore, SC can offer an alternative approach for sustainable soil tillage.
Complex fault-zone structure of the 2021 Yangbi Earthquake sequence revealed by dense array observations
Authors: Zeng Xianwei , Yu Chunquan , Zhang Gongheng
Published: March 2024

The 2021 MS 6.4 Yangbi earthquake occurred near the southwestern boundary of the Chuandian block in the SE Tibetan Plateau. Previous studies found that the mainshock occurred to the west of the main boundary fault – the Weixi-Qiaohou-Weishan fault, but the detailed seismogenic structure of the Yangbi earthquake sequence remains unclear. Accurate spatiotemporal characteristics of aftershocks and precise fault-zone structure are crucial for a more thorough understanding of the seismogenic structure and nucleation mechanisms of the Yangbi earthquake. Five days after the mainshock, we deployed a dense array with 200 short-period nodal seismometers spaced approximately 2 to 3 km in the vicinity of the Yangbi earthquake source region. In this study, we use the three-month-long continuous recordings of the dense array to study aftershock source parameters and fault-zone structures. We first obtained an earthquake catalog containing 88934 high-resolution event locations and 625 high-quality focal mechanisms. The entire aftershock sequence has a complete magnitude of -0.2, and a b-value of 0.97, with earthquake depths concentrated between 1 and 7 km below sea level. Combining precise aftershock locations and focal mechanisms, we constructed a detailed three-dimensional fault-zone structure model for the Yangbi earthquake sequence. The results reveal significant geometric variations in both strike and dip directions of the main fault. Along the dip direction, a conspicuous flower-like structure is present in the shallow part, transitioning to a listric structure inclined to the southwest at deeper levels. Along the strike direction, a noticeable bend exists in the central part. Several conjugate or intersecting faults are also present around the main fault. One of these faults, intersecting the main fault at a depth of about 4 km and dipping to the northeast, is likely the seismogenic fault of the largest foreshock. Additionally, below the main fault, there is another listric fault which appears to connect to the known Weixi-Qiaohou-Weishan fault at the surface. Our study provides new insight into the mechanism of the 2021 Yangbi earthquake sequence. The 3D fault-zone geometry can potentially be used for dynamic source modeling to better understand the initiation and rupture process of the mainshock.
Is the restoration of natural flows enough to reach a good ecological status of rivers?
Authors: Arrighi Chiara , De Simone Marco , Castelli Fabio
Published: March 2024

The objective of the European Water Framework Directive WFD (60/2000/EC) is to achieve or maintain at least a good ecological status of surface water bodies also by identifying appropriate e-flows. Water Management Plans issued by the Hydrographic District Authorities, based on the knowledge of the amount of water resources available, define e-flows and permitted water abstractions to support many human activities, e.g. domestic, agricultural etc. The objective of this work is to assess if the theoretical restoration of natural flows in river catchments allows to achieve a good ecological status of rivers. The method is based on the evaluation of natural and actual flows based on a 20-years water balance simulation implemented with a distributed, vector&raster based hydrological model capable of describing anthropogenic alterations, e.g., point abstractions, releases, reservoir regulations, etc. A new dimensionless index of eco-hydrological distance is defined to measure how far is a river flow from its ecological objectives based on actual flow regime and pressures acting on the catchment (e.g., land use, climate). The method is applied to a region in central Italy, with ca. 11,000 river reaches and mediterranean climate, where almost 50% of water bodies currently fails to achieve WFD objectives. The results show that for the summer season, which is the driest one in the study area, most of the rivers are pushed towards the limits of bad ecological status. Moreover, in 48% of rivers the summer natural flows, if restored, will not guarantee a good ecological status, due to the significant eco-hydrological distance from the target e-flows. AckonowledgementsThis study was carried out within the RETURN Extended Partnership and received funding from the European Union Next-GenerationEU (National Recovery and Resilience Plan – NRRP, Mission 4, Component 2, Investment 1.3 – D.D. 1243 2/8/2022, PE0000005). The study also received funding from the Hydrographic District of the Northern Appenines, Florence (Italy) Agreement “Esecuzione delle attività finalizzate alla redazione dei bilanci idrici su base modellistica dei corpi idrici superficiali appartenenti ai bacini toscani del distretto idrografico dell’Appennino Settentrionale ed alla definizione della metodologia da utilizzare per la definizione del deflusso ecologico”.