bluuebunny/crossref_metadata_2025 huggingface dataset:
A Non-Stationary Approach for Temporal Probability of Landslide using Hydrometeorological Thresholds
Authors: Dilama Shamsudeen Shamla , Sankaran Adarsh
Published: March 2024

Landslides are one of the natural hazards that endanger life and property. Landslide research emphasises prediction based on the probability of triggering factors such as rainfall for use in early warning systems, and has implications for effective risk mitigation. Recent studies have focused on the probability of a landslide occurrence depending on hydrological factors such as soil moisture. The objective of the current study is to determine the temporal probability of landslide occurrence in a non-stationary framework using hydrometeorological parameters such as soil moisture and rainfall. The study was conducted in the Wayanad district of Kerala, India and area was divided into different zones inorder to account the spatial variation of rainfall and the topographical influence on the soil moisture. The non-stationary temporal probability estimation was performed using the generalised extreme value analysis. The hydrometeorological parameters, gridded rainfall and soil moisture data collected over a 42-year period (1981–2021), were analysed for the non-stationarity characteristics using the statistical tests for trend detection and Pettit test for the change point analysis. A monotonical trend in non-stationarity of the parameters were observed in the different regions of Wayanad. The temporal probability estimation for the future time periods was performed using the bias corrected GCM data and the landslide inventory data. The results showed that the exceedance probability of soil moisture based on the covariates improves the temporal probability of landslides when compared to the rainfall-based approach. The study is a novel and effective method for improving landslide prediction based on hydrological and meteorological factors under changing climate conditions, and for incorporating the same in early warning systems.
Assessing instability of slow-moving landslides over Three Gorges area using InSAR techniques considering hydrogeological triggering factors
Authors: Xia Zhuge , Motagh Mahdi , Wang Wandi , Li Tao , Peng Mimi , Zhou Chao
Published: March 2024

Since the first impoundment in 2003 of the Three Gorges Reservoir (TGR), one of the largest reservoirs in the world, the issues of slope instability in the Three Gorges Area (TGA) have attracted significant worldwide attention. The operation of TGR, coupled with anthropogenic activities, has influenced slope instability and reactivation of plenty of landslides in the region. This study introduces a methodology to assess the slope instabilities over TGA using advanced integration of hydrological triggering factors with multi-temporal InSAR (MT-InSAR) techniques.Our approach involves characterizing the transient deformation of reservoir bank slopes under the coupling effect of rainfall and reservoir water level (RWL) changes. To achieve this, we propose a methodology that uses MT-InSAR analysis and regression analysis to identify triggering factors, taking into account the periods when slope instability is influenced by the drainage/storage period of the reservoir and seasonal rainfall. Determining the optimal window size for the triggering factors involves iterative searching through wavelet analysis, considering the time-lag between rainfall and RWL data. To extract step-like kinematic features for slowing-moving landslides, we apply a constrained least-squares optimization to InSAR-derived displacement time series. We then use independent component analysis (ICA) to isolate and recover the dominant source features, facilitating unsupervised spatiotemporal clustering to elucidate slope kinematics.This study utilized nearly 100 high-resolution Spotlight TerraSAR-X (TSX) and 50 medium-resolution Sentinel-1 (S1) SAR images captured between 2019 and 2021 to assess the slope instability. Here, we first test our proposed approaches for the single Huangtupo landslide in the TGA, which is one of China's largest reservoir-wading landslides along the Yangtze River; then, the approaches have been expanded to the whole study region near the Badong County. Overall, our proposed framework is transferable and can be applied to other local landslide or regional studies for monitoring slope instability and analyzing complicated cascading hazard chains.
Release and turn-over of carbon, nitrogen and metals under oxic and suboxic conditions in long-term incubations of Skagerrak sediments 
Authors: Siems Anna , Sanders Tina , Zimmermann Tristan , Wieser Michael E. , Pröfrock Daniel
Published: March 2024

Suspended particulate matter and associated pollutants from the entire North Sea are deposited in the Skagerrak, located between Norway and Denmark. Consequently, the sediments of the Skagerrak play a key role for long-term carbon storage within the North Sea. Due to its location and bathymetry, the bottom sediment redox conditions within the Skagerrak are heterogeneous and cover a wide range from oxic to suboxic conditions. We investigated nitrogen sequestration processes and the mobility of pollutants in these sediments during incubation experiments that simulated oxic and suboxic conditions. Analysis of isotopic fractionation was used as a tool to better understand the nitrogen sequestration pathways (δ15NO3-) and redox conditions (δ98/95Mo).Typically, incubation experiments last days to weeks but do not cover long-term effects. In contrast, we incubated different zones of three sediment cores with North Sea water for up to twelve months. The sediments originated from locations with (a) mainly iron reduction, (b) mainly manganese reduction and (c) both iron and manganese reduction. After one, three, six and twelve months, we sampled water and sediments from the incubations for various parameters (e.g., trace elements, carbon and nitrogen content, nutrients, δ15NO3-, δ98/95Mo). Under aerobic conditions, the sediments with high organic carbon content (2.78 ± 0.05 %) released up to 33 ± 6 µmol g‑1 NO3- during remineralization, while in anaerobic incubations, these sediments released only up to 4.8 ± 0.8 µmol g-1 NH4+. However, sediments with lower organic carbon contents (1.89 ± 0.05 %) released only 4.8 ± 1.2 µmol g‑1 NO3- and 1.18 ± 0.19 µmol g-1 NH4+, respectively. In combination with trace element concentrations, δ98/95Mo ratios allowed to distinct between different organic matter oxidation pathways. The aerobic incubations released mainly copper, lead and nickel while under  anaerobic conditions, also  cobalt but significantly less copper has been released. Hence, the prevailing oxygen conditions also have a strong impact on the remobilization of e.g., legacy pollutants stored in the sediments. The results of our long-term incubations reveal important biogeochemical processes and indicate that some processes are only traceable at larger timescales applied in this study, but not by incubation durations that are usually applied for biogeochemical studies.
HONO Retrievals over Asia from the Geostationary Environment Monitoring Spectrometer (GEMS)
Authors: Cha Hyeji , Kim Jhoon , Chong Heesung , González Abad Gonzalo , Ahn Dha Hyun , Park Sangseo , Lee Won-jin
Published: March 2024

The hydroxyl radical (OH) plays a significant role in the atmosphere, driving the oxidation and removal of most trace gases. Therefore, quantifying the sources of OH is of great importance to the scientific community. Researchers have been particularly interested in the role of nitrous acid (HONO) in tropospheric photochemistry, as HONO serves as a source of OH. While ground-based measurements have been conducted in certain regions, there is a need for more extensive observations of HONO to enhance our understanding of its chemistry. In this study, the HONO retrieval algorithm from the Geostationary Environment Monitoring Spectrometer (GEMS) are presented, utilizing the ultraviolet spectra. The retrieval process consists of three steps: spectral fitting, air mass factor calculation, and post-processing. The retrieval window of 343.0 – 371.0nm is employed to obtain HONO slant columns and air mass factor calculation is performed using a monochromatic wavelength of 357 nm. Reference sector correction is then applied to compensate for the HONO slant columns from radiance reference spectrum. Focusing on biomass burning events, the increase in HONO from fire plumes was presented as the retrieved results. By refining the retrieval algorithm, more information on HONO chemistry as well as diurnal patterns is expected to be obtained.
An Integrated Observatory for Redwood Forest Health and California Carbon Neutrality 
Authors: Suvocarev Kosana , Chu Housen , Klinek Lily , Miksch Matthew , Oldroyd Holly , Magney Troy , Chan Stephen , Biraud Sebastien , Paw U Kyaw Tha
Published: March 2024

Coastal redwood forests are among California’s most productive and largest carbon-storing natural ecosystems. However, there is a gap in knowledge on their water and carbon fluxes due to the lack of direct flux measurements. We received funding and advisory support from the State of California in order to address the water and carbon fluxes from redwood forest under declining fog conditions, different forest floor management, increasing droughts and other climate change threats during the period when the State is preparing for carbon neutrality goals (to be accomplished by 2045). Two tall eddy covariance towers will be installed in summer of 2024 to continuously monitor forest health at early and mid-seral growth stages (91 % of the coastal redwood forest ). Due to the complexity of terrain, we will equip the towers with the additional profile measurements throughout the canopy and downslope from the main towers to address the advection and  flux drainage. Occasional ancillary forest inventory surveys will be conducted within the flux footprint for improved data interpretation.  The study results will be uploaded to AmeriFlux and FLUXNET data repositories, and regularly communicated to the State agencies, advisory board and local communities through meetings and cooperative extension events. We invite suggestions for collaboration for continuing this project beyond the current timeline for long-term study and broader impact.  
The ongoing seismological research for the Central-Southern Aeolian Islands (CAVEAT project), Italy, from dense terrestrial seismic arrays
Authors: Granados-Chavarria Ivan , Di Luccio Francesca , Calò Marco , Lupi Matteo , Palano Mimmo , Famiani Daniela , Magnoni Federica , Scaltrito Antonio , Scognamiglio Laura , Tramelli Anna , Ursino Andrea , Ricci Tullio , Marchetti Alessandro
Published: March 2024

One of the tasks of the multidisciplinary project CAVEAT “Central-southern Aeolian islands: Volcanism and tEAring in the Tyrrhenian subduction system” was to deploy a dense seismic network composed by 120 wirelesss nodes, which were deployed for approximately 2 months on three islands of the Aeolian volcanic archipielago.The main goals of this data acquisition are to:detect and locate the shallow weak seismicity related to both volcanic and tectonic activity,
perform regional and local tomographic studies based on both passive methods and ambient noise cross-correlations (previously done for Lipari, Calò et al., 2023) to constrain the crust structure
characterize the source mechanisms.
In this work we show the details of the data acquisition strategy and the preliminary analyses of the continuous ambient noise records, to reconstruct the shallow structure of the Aeolian Arc. This study is part of the INGV Pianeta Dinamico project 2023-2025 CAVEAT “Central-southern Aeolian islands: Volcanism and tEAring in the Tyrrhenian subduction system” (grant no. CUP D53J19000170001) supported by the Italian Ministry of University and Research “Fondo finalizzato al rilancio degli investimenti delle amministrazioni centrali dello Stato e allo sviluppo del Paese, legge 145/2018.
The Triassic-Jurassic corridor of North America: are deep mantle structures a sufficient explanation for intracontinental magmatism?
Authors: Koptev Egor , Peace Alexander
Published: March 2024

Mesozoic intraplate igneous activity is abundant on the Canadian shield and includes multiple kimberlite fields, a province of alkaline magmatism, and individual bodies of kimberlites and ultramafic lamprophyres. Models have variously attributed the emplacement of these intrusions to the influence of Farallon plate subduction, opening of the Atlantic Ocean, or one or several Atlantic hotspots which North American plate is postulated to have drifted over during the Mesozoic. The latter hypothesis relies of the attribution of spatially, temporally and compositionally distributed and diverse magmatic rocks into a poorly defined, age-progressive, ‘corridor’ which may be derived from a common geochemical reservoir. In this study, we aim to test the spatiotemporal association between intraplate igneous activity along this postulated Triassic-Jurassic corridor and several elements of fixed mantle reference frame, such as the Atlantic hotspots and the hypothesised plume-generating zone (PGZ) of the African Large Low Shear Velocity province (LLSVP).We use published geochronological databases containing locations and isotopic ages of the Mesozoic intrusions of North America and published global plate reconstructions to dynamically calculate distances between the loci of intraplate magmatism and features of the upper and lower mantle assuming the latter remained fixed in the mantle reference frame throughout their history. We use GPlates 2.3.0 software package and pygplates 0.36.0 Python library to build the reconstructions and implement our calculations.Results demonstrate that none of the examined mantle features show a consistent association with all instances of intraplate magmatism across the Canadian shield during the Triassic-Jurassic. The coeval kimberlitic magmatism in the western Slave province (Jericho kimberlite field) and Baffin Island (Chidliak kimberlite field) appears to be completely spatially unrelated to any of the examined mantle features. The kimberlite fields of the Superior province (Attawapiskat, Kirkland Lake, Timiskaming) experience emplacements long before and after their passage over the PGZ, but their frequency increases in the PGZ’s vicinity, i.e. 76% of emplacement events in these provinces occur within 200 km of the PGZ’s surface projection.Our results show that intraplate magmatism across many Triassic-Jurassic fields of North America could be initiated independently of the influence of deep mantle structures. Thereby, a geodynamic mechanism nested in the asthenosphere or lithospheric mantle suffices for melt generation in an intraplate setting. However, it cannot be ruled out whether proximity to deep mantle structures is capable of facilitating “shallow” melt generation and emplacement and that deep-seated mantle structures could provide an influx of fluids or thermal energy, increasing melting intensity and volume.
Statistics of the Subgrid Cloud of an Idealized Tropical Cyclone at Convection-Permitting Resolution
Authors: Zhang Xu , Bao Jian-Wen
Published: March 2024

Large-eddy simulations of an idealized tropical cyclone (TC) were conducted as benchmarks to provide statistical information about subgrid convective clouds at a convection-permitting resolution over a TC convection system in different stages. The focus was on the vertical and spatial distributions of the subgrid cloud and associated mass flux that need to be parameterized in convection-permitting models. Results showed that the characteristics of the subgrid clouds varied significantly in various parts of the TC convection system. Statistical analysis revealed that the subgrid clouds were mainly located in the lower troposphere and exhibited shallow vertical extents of less than 4 km. The subgrid clouds were also classified into various cloud regimes according to the maximum mass flux height. Local subgrid clouds differed in mass-flux profile shape and magnitude at various regimes in the TC convection system.
Visibility and Fog Synoptic and Mesoscale Variability over Marambio Base, Antarctic Peninsula
Authors: Jimenez Garcia Mauricio , Mejia John , Henao Juan Jose , Troche Noemi , Martinez Alvaro Rafael , Chicaeme Kevin Alexander
Published: March 2024

Summertime aviation, research, and field campaigns in Marambio Base, Antarctic Peninsula (AP), and surrounding areas, are frequently affected by low visibility and fog.  Additionally, upper-air soundings in the area are launched weekly, limiting the study of the synoptic time scale variability of these hazards. A special field campaign was designed to fill this observational gap, and to examine the drivers of fog events.  A three week-long intensive observation campaign during February 2023 successfully captured the evolution and vertical structure of two multiday fog episodes that were later interrupted by westerly Foehn winds, favoring sudden warming, drying, and clear skies over eastern flank of the AP.  This dataset is also used to evaluate and assess the skill of regional climate simulations using the Global Forecasting Systems data and the Polar-WRF model.  We carried out the later modeling activities to examine the mesoscale characteristics of the interplay between the fog episodes and the Foehn winds.  This study shows the analyses of the special upper-air observations and modeling simulations, with emphasis in the description of the observable and predictable mesoscale ingredients and their relationship with synoptic forcings. We found a cycle that modulates visibility and fog: (i) low visibility ahead of the synoptic trough bringing a deep northerly moistening and warming dominating warm advection fog on the northeastern side of the AP; (ii) an enhanced mid-level inversion is formed by adiabatic warming due to westerly winds on the lee side of the AP limiting mixing; (iii) visibility increases as Foehn winds warm up and dry out the low-level atmosphere west of the AP; (iii) a meso-low (heat-low) developed on the lee side of the AP that later moved eastward with the synoptic trough, bringing cooler southerly air masses that lower visibility and favoring cold advection fog; finally (iv) cooling is maintained ahead of the synoptic ridge sustaining cold advection fog.  Polar-WRF helped us diagnose the mechanistic nature of the fog events, while providing intricate multiscale connections modulating visibility in the region.
Imaging land subsidence and slow slip transients by combining InSAR and GNSS 
Authors: Aoki Yosuke
Published: March 2024

SAR and GNSS are two dominant techniques to measure the Earth's deformation. They have different characteristics in that InSAR has superior spatial resolution, and GNSS has superior temporal resolution. Also, GNSS has better precision than InSAR, and InSAR measurements have significant spatial correlation mainly because of the atmospheric disturbance. Therefore, if available, InSAR measurements will be more precise when combined with GNSS measurements. This study investigates the temporal evolution of land subsidence and slow slip transients in the Boso Peninsula, Japan, from InSAR and GNSS measurements. First, we generated interferograms of available ALOS-2 images. The generated interferograms are corrected to be consistent with GNSS measurements every 20 km or so. The correction assumes that the spatial variation of the noise in InSAR measurements is represented as a polynomial function, the degree of which is constrained adaptively. Then, the corrected interferograms are fed to the time-series analysis. The time series generated allows us to separate continuing subsidence of up to 20 mm/yr with a shorter wavelength and slow slip transients with a longer wavelength. 
Evaluating Current Statistical and Dynamical Forecast Techniques for Seasonal United States Coastal Sea Level Prediction
Authors: Newman Matthew , Long Xiaoyu , Shin Sang-Ik
Published: March 2024

The need for skillful seasonal prediction of coastal sea level anomalies has become increasingly evident as climate change has increased the risk of coastal flooding events. Aiming to improve our ability to forecast coastal inundation risk on seasonal and longer time scales, NOAA and NASA initiated the RISE project, a collaborative effort focused on developing and assessing novel dynamical and statistical forecast methods for coastal sea level and inundation risk for US coasts. This presentation is an outgrowth of that project, initially based on a pilot study of monthly sea level anomaly forecast skill assessed at two tide gauge stations, San Diego CA, and Charleston SC. In this study, we evaluate several current forecast systems -- NCAR Community Climate System Model Version 4 (CCSM4), GFDL Seamless System for Prediction and Earth System Research (SPEAR), and ECMWF Seasonal Forecast System 5 (SEAS5) -- by calculating deterministic and probabilistic skill from a few decades (1993-2015) of their retrospective forecasts (“hindcasts”) and for lead times of up to 6-9 months. Additionally, we examine potential local enhancement of hindcast skill by two post-processing downscaling techniques, an observationally-based multivariate linear regression and a hybrid dynamical model approach, using the adjoint model of the Estimating Circulation and Climate of the Ocean (ECCO) system forced by observed and model-predicted surface forcings.We find that all these approaches face challenges stemming from whether the modeled sea surface height sufficiently represents observed local variations of coastal sea level, because of ocean model limitations and because of inadequacies in both model initialization and ensemble spread. Some of these issues also complicate the ability of the downscaling techniques to improve probabilistic skill, even though they do somewhat improve deterministic skill. In general, while deterministic hindcast skill is considerably higher for San Diego than Charleston, ensemble spread metrics such as forecast reliability and sharpness are mediocre for both locations. Additionally, evaluating how well any technique predicts seasonal coastal sea level variations is considerably complicated by the forced trend component and particularly how it is estimated, especially for Charleston; .essentially, skill assessment of US coastal sea level seasonal prediction is also a trend detection problem. Moreover, these results are largely matched by hindcasts from a Linear Inverse Model (LIM), a simple stochastically-forced linear prediction model constructed from observations, suggesting that substantial improvement still remains for coastal sea level prediction.
Detecting Field-level Crop Residue Cover across the EU Using Multi-source Satellite Data and Explainable Machine Learning
Authors: Wang Sheng , Yuan Boqin , Guan Kaiyu , Olesen Jørgen Eivind , Zhou Rui , Gislum René
Published: March 2024

Conservation tillage practices with crop residues covering soils can improve soil health to increase agronomic and environmental benefits for croplands. Accurate information of field-level crop residue cover is highly important for evaluating the implementation of government conservation programs and voluntary ecosystem service markets, as well as supporting agroecosystem modeling to quantify cropland biogeochemical processes. Remote sensing has been demonstrated to detect crop residue cover cost-effectively, yet existing regional-scale studies in Europe are rare. To fill this data gap, our study developed an explainable machine learning algorithm to integrate multi-source satellite data (Sentinel-2, Sentinel-1, and SMAP soil moisture) to quantify crop residue presence for the EU croplands. Specifically, we utilized satellite time series data of optical spectral tillage index, soil background reflectance, soil moisture, and SAR backscattering information to detect field-level crop residue cover. With 41,325 ground records of 10 major crops, we developed highly robust and explainable machine learning models with unbalanced label correction approaches to predict residue presence. Results show that models achieved high accuracy of 0.78 and F1-score of 0.70 to detect crop residue presence. We also aggregated field-level estimates to the regional level, which shows high match with regional census data. Among crop types, wheat and barley got higher prediction performance than other crop types. Our work highlights the feasibility of integrating multi-source satellite data with machine learning for detecting field-level crop residue cover at continental scale across the EU. These crop residue datasets can support analyzing the spatiotemporal variability of tillage practices across the EU and their potential impact on agroecosystem productivity and sustainability. 
Study on energy and CO2 flux in a monsoon temperate rice paddy and soybean field in Korea
Authors: Kang Mingu , Shim Kyo-moon , Kim Yongseok , Hur Jina , Jo Sera , Kim Eungsup , Hong Sueng-gil
Published: March 2024

  Unlike natural ecosystems, agricultural ecosystems are unique ecosystems in which artificial factors play a significant role. The material cycling within an agricultural ecosystem is influenced by factors such as agricultural activities, weather, and soil conditions. Understanding the material cycling and energy flow in these ecosystems is important to cope with climate change. In this study, we measured energy and carbon dioxide flux using the eddy covariance method to assess material cycling in rice paddy and soybean field ecosystems with similar weather conditions but different vegetation. Additionally, growth surveys were conducted every two weeks to analyze crop development. During the summer, the weather and soil conditions in rice paddy and soybean field were comparable, resulting in similar levels of latent heat flux for both ecosystems. In July 2020, despite the rainy season, the water use efficiency(WUE) of rice paddy was higher than that of other periods, influenced by vegetation and weather conditions. WUE during the summer resembled that of the cropping period, indicating a potential impact on overall crop grain weight.
The Effects of Viscosity on the Linear Stability of  Damped Stokes Waves, Downshifting,  and Rogue Wave Generation}
Authors: Schober Constance
Published: March 2024

In this talk we examine  a higher order nonlinear Schr\"odinger equation with linear damping and weak viscosity, recently proposed as a model for deep water waves exhibiting frequency downshifting. Through analysis and numerical simulations, we discuss how the viscosity affects the linear stability of the Stokes wave solution, enhances rogue wave formation, and leads to permanent downshift in the spectral peak. The novel results in this work include the analysis of the transition  from the initial Benjamin-Feir instability to a predominantly oscillatory behavior, which takes place in a time interval when most rogue wave activity occurs. In addition, we propose new criteria for downshifting in the spectral peak and determine the relation between the time of permanent downshift and the location of the global minimum of the momentum and the magnitude of its second derivative.
A framework for multi-hazard risk indicators
Authors: Arosio Marcello , White Christopher J. , Gani Adnan Mohammed Sarfaraz , Martina Mario , Kennedy Claire
Published: March 2024

The occurrence of multiple hazards poses significant risks to both human lives and assets. These risks often surpass those associated with individual hazards as they result from the interaction of natural hazards through simultaneous, cascading, or cumulative incidents. In several European regions, vulnerable to a range of climatic extremes, the society and environment are expected to undergo significant impacts in the next few decades. This is attributed to the rising frequency and severity of multi-hazard events, which are closely tied to changing climatic conditions.In this context, the aim of this work is to develop and test a new framework for multi-hazard risk indicators that are suitable for use in risk-based assessments and decisions making. Indicators are used within different disciplines, offering insights into hazards, risk, resilience, vulnerability and other impacts related to climate change, amongst other factors. Such indicators can be used to model interacting hazards and cascading impacts within risk assessments, including a decision support system for multi-hazard disaster risk. This work, supported by a systematic literature review grounded on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA), introduces a framework for a suite of simple and usable multi-hazard indicators that balance complexity and usability to enable their uptake within natural hazard risk assessments (e.g., multi-hazard/risk rate). We adopt the following definition “Indicators are observable and measurable characteristics that can be used to simplify information to help understand the state of a concept or phenomenon, and/or to monitor it over time to show changes or progress towards achieving a specific change”. The development of these indicators prioritises the needs of end-users in disaster risk management, aiming to overcome limitations associated with their evolution being driven by climate scientists, without considering sectoral impacts or risk-based assessments. The framework for indicator development can contribute valuable insights for progressing multi-hazard risk management policies globally, particularly in regions experiencing an increased susceptibility to multi-hazard events.The research has been carried out within the framework of the Horizon Europe project MEDiate (Multi-hazard and risk-informed system for Enhanced local and regional Disaster risk management). The primary objective of this project is to create a decision-support system (DSS) for disaster risk management that takes into account the complexities of multiple interacting natural hazards and their cascading impacts. The framework is implemented on four interactive multi-hazard pairs—compounding coastal and riverine flooding, extreme heat and drought, extreme wind and precipitation, and extreme precipitation and landslides—in four European testbeds: Oslo (Norway), Nice (France), Essex (UK), and Múlaþing (Iceland), respectively.
Distribution of biological soil crusts in the Tibetan Plateau
Authors: Zhou Zhixin , Chen Ning , Ma Li , Yang Liping , Jiang Hongyu , Wang Siqing
Published: March 2024

Biological soil crust (biocrust) is regarded as a self-organizing principle, and widely distributes in the Tibetan Plateau, which is a crucial ecological security area of China and water towel of Asia. Unfolding biocrust distribution in the region is critical to maintain ecosystem functions and services therein. However, we know little about explicit distribution of biocrust in the Tibet Plateau. To that end, this study combined field survey, reference compiling and random forest algorithm to explore the spatial distribution of biocrusts on Tibetan Plateau and the associated driving factors. A total of 203 data points had been collected. We found that the biocrusts cover up to 20% of the soil surface in the Tibetan Plateau and mainly cover the Qaidam Basin and the northern Tibetan Plateau, but less in the Qiangtang Plateau and the southeastern Tibetan Plateau.The dominating factors affecting biocrust distribution are soil clay content, altitude, average temperature of the hottest season, pH, and soil organic carbon content. Specifically, biocrust acclimatization is positively affected by lower soil clay content and elevation, hotter quarter temperatures (especially greater than 8°C), and greater pH, while negatively affected by higher soil organic carbon content. Overall, this study sheds light on biocrust distribution in the Tibetan Plateau, and will significantly expand our understandings of biocrusts.
A similarly warm but drier Mediterranean region at the Miocene - Pliocene transition
Authors: Vasiliev-Popa Iuliana , Agiadi Konstantina , Methner Katharina , Fiebig Jens , Mulch Andreas
Published: March 2024

Between 5.97-5.33 Ma, kilometre-thick evaporite units were deposited in the Mediterranean Basin during an event known as the Messinian Salinity Crisis (MSC). The MSC was characterised by a strongly negative hydrological budget, with a net evaporative loss of Mediterranean basin water exceeding precipitation and riverine runoff inputs. Despite evident proves of environmental crisis at the end of the Messinian, the Mediterranean domain still lacks quantitative estimates of temperature change across the transition from the (brackish) Lago Mare, marking the end of the Miocene, to the fully marine Pliocene. Here we reconstruct continental mean annual temperatures (MAT) using branched glycerol dialkyl glycerol tetraether (brGDGT) biomarkers for the time period corresponding to the MSC Stage 3 (5.55-5.33 Ma) and compare them with continental temperature values obtained from Δ47 clumped isotope geochemistry measured on paleosol carbonate nodules found at few locations in the Mediterranean basin. The well-preserved organic biomarkers were extracted from outcrops onshore and offshore covering a vast portion of the Mediterranean Basin; onshore (Malaga, Sicily, Cyprus) and offshore (DSDP core holes 124 and 134 from the Balearic abyssal plane, hole 374 from the Ionian Basin and hole 376 drilled west of Cyprus). Calculated MATs for the 5.55 to 5.33 Ma time interval show values around 16 to 19 ºC for the Malaga, Sicily and Cyprus outcrops. The MAT values calculated for DSDP Leg 13 holes 124, 134 and Leg 42A holes 374 and 376 are lower, around 13 to 16 ºC. Comparing the brGDGT-MAT values with Δ47-MAT values from carbonate nodules, shows high congruence between both approaches. For the northern Mediterranean Δ47-MAT is 24.6 ± 1.6 °C and brGDGT-MAT is 19 ± 4.8 ºC. For Cyprus Δ47-MAT is 20.3 ± 1.7 °C and brGDGT-MAT is 18 ºC ± 4.8 ºC. Given the very different nature of the used paleoproxies, the similarity of the obtained MAT values provides a strong indication of their (cross)validity in sampled sections. Additionally, the measured δ18O values for the carbonate nodules used for the Δ47-MAT show high δ18O of the soil water (in the range of -5 ±0.7‰) indicate highly evaporative conditions for the two onland sites where these were collected (Northern Apennines and Cyprus). We conclude that between 5.55 to 5.33 Ma the temperatures in the Mediterranean region were similar to present-day conditions, yet the region has suffered from excess evaporation as indicated by combined high δ18O values from (inorganic) carbonate nodules and δ2H values from (organic) biomarkers.
Human-Earth feedbacks in E3SM-GCAM successfully simulate the evolution of a combined human-Earth system
Authors: Di Vittorio Alan , Hao Dalei , Shippert Timothy , Singh Balwinder , Sinha Eva , Bond-Lamberty Ben
Published: March 2024

Understanding human-environment feedbacks is becoming increasingly important as climate change mitigation and adaptation strategies continue to diversify, target new areas, and grow in extent. Incorporating these feedbacks into models is critical for assessing the effectiveness of such strategies and how they may change in response to a changing climate. For example, projected forest expansion varies with changing climate because climate-driven changes in forest productivity affect the cost-effectiveness of reforestation strategies. Including human-environment feedbacks in models can dramatically change the projected scenario as human systems respond to the changing environment, which in turn affects the Earth system projection. We have incorporated human-Earth feedbacks in a synchronously coupled system comprising the Global Change Analysis Model (GCAM) and the Energy Exascale Earth System Model (E3SM). GCAM is the core model in a new E3SM human component that is at the same level as the Earth model components (land, atmosphere, ocean, etc.) and interacts with them through the shared coupling software. Terrestrial productivity is passed from E3SM to GCAM to make climate-responsive land use and CO2 emission projections for the next five-year period, which are interpolated and passed to E3SM annually. Previous experiments with a similar model have shown that the incorporation of these feedbacks affects land use/cover change, crop prices, terrestrial carbon, local surface temperature, and land carbon-atmosphere feedbacks. Preliminary results indicate that this newly coupled system is robust in relation to the previous experiments. The human scenario is altered by terrestrial feedbacks, which in turn changes the Earth system projections. Regional differences are more pronounced than global differences due to regional shifts in land use. This new coupling addresses inconsistency across models, enables a new type of scenario development, and provides a modeling framework that is more easily updated and expanded.
Assessing stratospheric aerosols contamination due to space activities
Authors: Lasue Jeremie , Määttänen Anni , Zolensky Michael , Ravetta François , Grunewald Augustin
Published: March 2024

The life cycle of a spacecraft starts and ends in the atmosphere: it interacts with the atmosphere right after the launch and during the atmospheric reentry when it usually mostly ablates. Both phases induce emissions of gases and solid particles, providing a source of these components in the middle atmosphere. Little is known about the exact nature, composition and effects of these emissions on the atmosphere and climate, but their impact is expected to rise as more and more orbiting satellites are launched. Ever since the years 2000, the number of space rockets launched per year has increased by a factor 3 globally. At the same time, the number of satellites launched in orbit around the Earth per year has been multiplied by about 30. One may wonder whether changes in the anthropogenic material injected in the terrestrial stratosphere can be detected and what its influence may be. In order to study the cosmic dust particles arriving on Earth, the NASA Johnson Space Center (JSC) has been systematically collecting solid dust particles from the Earth’s stratosphere by aircraft equipped with dedicated particle collectors since 1981. So far, 25 catalogs have been published, covering campaigns of collection from 1981 to 2020, with a total of 5071 solid particles that have been preliminary characterized and curated. In this work, we use the preliminary classification of the dust particles. Based on SEM images and X-ray EDS composition the collected dust is separated into four groups: C (Cosmic), TCN (Terrestrial Contaminant Natural), TCA (Terrestrial Contaminant Artificial) and AOS (Aluminum Oxide Sphere). The AOS being mostly generated by solid rocket propellant, they also belong to the TCA class. Our analysis of the data published indicates that from 1980 to 2009 the cosmic dust particles typically represent on average 40% of the collection with TCA and TCN corresponding to about 30% each. In the recent years, the TCA fraction has doubled to about 60% of the collection (2010-2020). This increase in anthropogenic particles is likely due to the overall human space activity and its recent increase. We will present the properties of the solid stratospheric dust particles collected and their evolution with time.Future work will be dedicated to better classify the natural and anthropogenic particles collected and described in the existing databases. We will use numerical modelling to produce quantitative estimates of the injected mass, the lifetime of particles in the middle atmosphere (stratosphere) and the relative abundance of the anthropogenic particles with respect to the stratospheric background particle population.
Deriving dynamic reservoir operating policy under the changing precipitation and inflow patterns in snow-dominated Himalayan regions 
Authors: Pattabiraman Balasundaram , Kasiviswanathan Kasipillai Sudalaimuthu
Published: March 2024

The impacts of climate change and complex local weather in the Himalayan region tend to change the characteristics of the precipitation, leading to a high non-stationarity. While studies have been performed to analyse the change in the rainfall pattern due to climate change, no attempts were made for the quantifiable impacts linking with reservoir operating policy. The assumption of stationary while deriving the operating policy of reservoirs is prevalent due to less computational effort. Reservoirs built for hydropower generation is expected to meet the energy demands that largely varies. Thus, adopting the conventional stationary operating policy derived based on the historical data might lead to create a havoc leading to underutilized when the reservoir operation is mainly meant for hydropower generation. In this study, the influence of alterations in the meteorological and inflow pattern on the dynamics of operation policy is explored for the reservoirs located in the snow dominated Himalayan region (Tehri reservoir). To demonstrate the proposed simulation optimization framework, the daily gridded rainfall data (0.25o x 0.25o) for the period 1901 - 2021 collected from Indian Meteorological Department and monthly inflow of tehri reservoir for the period 1965 - 2021 was used.  Several statistical methods were employed to quantify the alterations in the precipitation data and inflow to the reservoirs. A stochastic optimization algorithm was applied to derive the dynamic reservoir rule curves for maximizing the hydropower generation including the weighted over-shifting and seasonality. The statistical analysis of both precipitation and inflow shows negative trend during the drawdown periods (January, March, October, and December) with a mean release of 170 MCM. Further, the alteration in precipitation and inflow is dynamically accounted in operating policy under two release scenarios (i.e. scenario 1 by increasing reservoir release (10%, 20%, 30%) in the negative trend period and decreasing release in the positive trend period and scenario 2 by only increasing release during negative trend period). It is found that the scenario 2 (only increase in release) have resulted in higher hydropower generation. In addition, the changing pattern of the precipitation and inflow is performed by superimposing principle the assessed similar performance in hydropower generation. The outcome of the study indicates the adaptivity of developed framework and applied in other reservoirs under changing environment.Keywords: Reservoir Operation, Rule curve, Pumped storage, Hydropower.
Direct dating of global Cryogenian sections by in situ U–Pb mapping of carbonates
Authors: Subarkah Darwinaji , Collins Alan , Löhr Stefan , Nixon Angus , Blades Morgan , Farkas Juraj , Lloyd Jarred , Klaebe Robert , Gilbert Sarah , Virgo Georgina
Published: March 2024

The Cryogenian period represents a critical interval in Earth’s history, characterized by drastic tectonic and environmental changes. Evidence of low-altitude glacial deposits from this time has been recognized globally, alluding to the most extensive icehouse regimes known on our planet. These conditions of successive global freezing and warming during the Neoproterozoic have been dubbed as ‘Snowball Earth’ events. Importantly, the Cryogenian may have played a key role in the accelerated evolution of early life, as microorganisms became more complex and abundant after this period. Consequently, it is important to constrain the absolute timing, duration, and termination of these glacial and interglacial events. Despite their significance, robust, direct dating of Cryogenian sections remains challenging. The most accurate way to constrain these units is through dating of interbedded volcanics. However, they are not present across all sections globally, making correlations difficult to establish.As such, we present a novel strategy to address this issue by directly dating a broad array of Cryogenian carbonates through an in situ U-Pb mapping approach. Our case study includes inter-glacial and post-glacial carbonates from sections in Australia, Oman, and Greenland. We show that this method allows for the concurrent collection of geochemical, petrographic, and geochronological information at sufficient precision to address key geological questions. Geochemical proxies such as elevated Mn/Sr ratios and Al or Si can be used to filter areas affected by alteration or detrital input, respectively. Secondary phases such as veins and overgrowths can also be petrographically avoided as an advantage of the spatially coherent mapping technique. Regions that yield enrichment in U and best spread in U–Pb ratios can be preferentially selected. Triaging such datasets and spatial information can help identify subdomains within a sample that is most suitable for dating, maximizing the success rate of this approach. The technique is capable of yielding age precision of ±1% depending on the concentration of U, the range in radiogenic isotopes, and the number of pixels that make up an analytical point.  
Immobilization of radioactive Th by coprecipitation with lead apatites
Authors: Manecki Maciej , Wrona Patrycja , Brzoska Aleksandra , Staszel Kacper
Published: March 2024

There is a constant search for materials that could be used as geochemical barriers and fillers for radioactive waste storage containers. One of effective methods of immobilizing toxic elements is their precipitation in the form of sparingly soluble crystalline phases. The purpose of this study was to test the effectiveness of co-precipitation of Th from aqueous solutions in the form of crystalline lead phosphates. Such phases have high stability and low solubility and the presence of Pb has an additional effect on reducing the radiation.Three sets of experiments were carried out by adding reagents into a solution containing non-radioactive Th at a concentration of 400 ppm:(A) a solution containing PO43- ions (at a concentration of 1 g/L);(B) a solution containing Pb2+ and a solution containing PO43- ions (at concentrations of 3.5 g/L and 1 g/L, respectively) added dropwise simultaneously;(C) solutions containing Pb2+, PO43-, and Cl- ions (at concentrations of 3.5 g/L, 1.0 g/L, and 0.12 g/L, respectively) added dropwise simultaneously.All experiments were repeated at pH = 3, 5 and 7. No reaction occurred in experiment (A), while in experiments (B) and (C) the solid phases crystallized, and the Th concentration dropped from 400 to about 0.05 ppm. In the absence of Cl (experiment B), the reaction at pH=3 led to the formation of "phosphoschultenite" PbHPO4 while at pH = 5 and 7 Th-bearing hydroxylpyromorphite Pb5(PO4)3OH was formed. In the presence of Cl ions (experiments C), Th-bearing pyromorphite Pb5(PO4)3Cl was formed over the entire pH range. Th was removed from solution by coprecipitation with Pb and incorporation of Th into lead phosphate structure.The results showed that Pb must be present for Th to be effectively immobilized from solution in the form of phosphate phases. The presence of Cl is not as important as the presence of Pb in terms of removal efficiency, but it may be crucial for the long-term stability of the precipitated phases, since Pb5(PO4)3Cl has higher stability and lower solubility than Pb5(PO4)3OH. These findings pave the way for development of potential innovative techniques for immobilizing Th from waste and contaminated solutions, which could have implications for the safety and long-term viability of various nuclear waste disposal programs. This research was funded by National Science Center research grant no. 2021/43/O/ST10/01282.