bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary producer dominated environments of the Ediacaran-Cambrian transition: palaeontological insights from the Mackenzie Mountains, Canada
Authors: Agic Heda , Smith Martin , Kovalick Alex
Published: February 2023

The early evolution of macroscopic life, including the Cambrian ‘explosion’ of animals, took place over more than 100 million years against the backdrop of dynamic environmental changes like unstable redox conditions and nutrient supply. The terminal Ediacaran to early Cambrian transition is marked by the appearance of macroscopic biomineralizers, but also a seeming decline in diversity, in contrast to rich communities of macroscopic Ediacara-type biota preserved in older units worldwide. Our understanding of this biotic change as well as its environmental divers suffers from stratigraphic incompleteness, as continuous mid and upper Ediacaran, and Cambrian strata are rarely exposed in a continuous sequence in the same area, or represent different depositional settings.The Mackenzie Mountains in the Northwest Territories, Canada are a home to a nearly continuous sedimentary succession from the Cryogenian to the Cambrian and as such, provide a great target to analyse biotic and environmental changes through time. We have investigated the interval of carbonates and siliciclastics through the Blueflower, Risky, Ingta, Backbone, and Vampire formations and present integrated palaeontological and geochemical data to produce a high resolution biostratigraphic and chemostratigraphic profile for the Ediacaran-Cambrian boundary interval.The Ediacaran-Cambrian boundary occurs in the Ingta Formation, marked by sporadic trace fossils Treptichnus and Harlaniella. Simple surficial traces Planolites occur throughout the formation. Also common are well-preserved bacterial filamentous organic-walled microfossils in mudrocks, but the boundary interval lacks complex acritarchs or cuticular animal remains. Macroscopic carbonaceous fossil problematica were also recovered. Complex trace fossils occur in the overlying Backbone Ranges Formation and become more common in the Vampire Formation, but are absent from the lowermost Cambrian strata in the Mackenzie Mountains. The primary producer dominated environment and the absence of organically preserved animal remains in a setting conducive to organic preservation imply a true decline in diversity through the boundary interval – possibly a result of either phylogeny or ecology.
Solar Orbiter reveals that reconnection jets cluster in the solar wind
Authors: Fargette Naïs , Lavraud Benoit , Rouillard Alexis , Houdayer Pierre , Phan Tai , Oieroset Marit , Eastwood Jonathan , Fedorov Andrei , Louarn Philippe , Owen Christopher , Horbury Tim
Published: February 2023

Magnetic reconnection is a fundamental process in astrophysical plasma, as it enables the dissipation of energy at kinetic scales. Detecting it in-situ is therefore key to further our understanding of energy conversion in space plasma. However, ion reconnection jets usually scale from seconds to minutes in-situ, and as such they can be quite tedious to find in the months or years of data provided by Wind, ACE, Helios, PSP and Solar Orbiter.In this work, we use a new approach to identify automatically reconnection exhausts in-situ. The method strongly relies on the Walén relation and uses Bayesian inference as well as physical considerations to detect reconnection jets in-situ. Applying the detection algorithm to one month of Solar Orbiter data at 0.7 ~AU, we find an occurrence rate of 6.4~jets/day, which is significantly higher than in previous studies performed at 1~AU.  We repeat the analysis over the Solar Orbiter perihelion at 0.3 AU and show that the occurrence rate of magnetic reconnection tends to increase with radial distance.We show that magnetic reconnection exhausts clearly cluster in the solar wind. We perform a statistical analysis, distinguishing between the exhausts associated with the heliospheric current sheet and turbulent reconnection. We find that the source and the degree of Alfvénicity of the solar wind might have an impact on magnetic reconnection occurrence.
Assessing tidal salt marsh elevation along the coast of Maine, United States using unmanned aerial systems (UAS) and stable carbon isotopes
Authors: Autery Molly , Woodruff Jonathan , Johnson Beverly , Peck Erin , Wicks Ryan , Ward Joshua
Published: February 2023

Elevation is a key control on the frequency and duration of flooding experienced by a salt marsh over the course of the tidal cycle, which in turn modulates the deposition of sediment onto the marsh surface. The amount of sediment deposited onto the marsh surface is an important factor in the development of the salt marsh and its ability to withstand sea level rise. Human interference in the form of agricultural practices (e.g., ditching and embayments) and mosquito control significantly altered the structure and function of salt marshes throughout New England with lasting impacts on marsh platform elevation and, consequently, the persistence of salt marshes in the face of sea level rise. This study establishes the present-day distribution of elevation and vegetation zones for a salt marsh in Maine, United States, and compares these baseline measurements to past estimates of elevation made using carbon stable isotopes (δ13C) measured in sediment cores. A LiDAR scan and a series of multispectral air photos were collected from a representative salt marsh in Maine (Cousins River Marsh, Yarmouth, ME). The LiDAR scan is processed to create a digital elevation model (DEM) of the marsh and the air photos are converted into a 2D digital model of the marsh platform. In New England salt marshes, an elevation-mediated gradient in vegetation exists across the marsh surface, with the most salt-tolerant species residing in lower-elevation areas. Different species of marsh grasses produce varying δ13C values, and once incorporated into the marsh peat, can potentially be used to identify changes in vegetation cover through time. Sediment cores collected from Cousins River are sub-sampled and analyzed for down-core variations in δ13C to assess salt marsh paleovegetation. Short-term radioisotopes 210Pb and 137Cs are used to produce age-depth models by integrating sedimentation over ~100 and ~70 years, respectively, and are correlated to stable carbon isotope results for an approximation of salt marsh elevation change. Results will inform our understanding of the relative influences of sea level rise and human-driven landscape alteration on salt marsh morphodynamics along the coast of Maine, with implications for salt marshes throughout New England.
Oceanic gyres in the Arctic
Authors: Aksenov Yevgeny , Rynders Stefanie , Megann Alex , Nurser A.J. George , Wilson Chris , Coward Andrew C.
Published: February 2023

The Arctic can be seen as a two-layer ocean: thin (<100m) mixed layer at the surface, and the rest of the weakly-stratified ~5-km water column, separated from the surface waters by the Arctic halocline. The weak subsurface ocean stratification results in most of the ocean flow being depth-uniform and guided by bathymetry. One way to look at the Arctic long-term, large-scale ocean circulation is examining the Arctic gyres and cross-ocean currents, such as the Trans-Polar Drift. Wilson et all 2021[1] show how gyres, saddle points and flow separation structures “separatrices” in the surface ocean circulation changes between years and how these affect cross-basin Arctic oceanic connectivity. We extend the method to the subsurface oceanic flow and examine barotropic circulation in the present-day Arctic Ocean using global NEMO model (Nucleus for European Modelling of the Ocean) at 3-km horizontal resolution. The closed-gyre detection method allows us to map positions of the principal Arctic gyres and quantify their strength. The Montgomery potential analyses complements the study by giving us an insight in the geostrophic flows of the Atlantic and Pacific waters. The results suggest a large year-to-year variability of the Arctic gyres and the changes in the Arctic – the Nordic Sea connectivity, which impacts exports of the freshwater, heat, and biogeochemical tracers from the Arctic.This work has been funded from LTS-S CLASS (Climate–Linked Atlantic Sector Science, grant NE/R015953/1), from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 820989 (project COMFORT), from the project EPOC, EU grant 101059547 and UKRI grant 10038003 and from the UK NERC project CANARI (NE/W004984/1).Reference[1] Wilson, C., Aksenov, Y., Rynders, S. et al. Significant variability of structure and predictability of Arctic Ocean surface pathways affects basinwide connectivity. Commun. Earth. Environ. 2, 164 (2021). https://doi.org/10.1038/s43247-021-00237-0.
Reprocessing of Copernicus Sentinel POD solutions with COST-G geopotential models
Authors: Berzosa Javier , Fernández Martín Carlos , Matuszak Marek , Fernández Usón Marc , Fernández Sánchez Jaime , Nogueira Lodd Carolina , Femenias Pierre , Peter Heike , Meyer Ulrich
Published: February 2023

The Copernicus Precise Orbit Determination (CPOD) Service generates routinely precise orbital products of Sentinel-1, -2, -3 and -6 for its operational use by ESA and EUMETSAT. The accuracy of these products depends on the quality of the inputs used, particularly the gravity field and the GNSS orbits and clocks. This abstract focusses on the impact of the gravity field using the COST-G geopotential models.Currently, the CPOD Service is using the EIGEN-GRGS-RL04 mean gravity field model, which dates back in 2019. In the framework of COST-G (Combination Service for Time-variable Gravity Fields) a new series of gravity fields is being generated quarterly by AIUB (Astronomical Institute, University of Bern), as a fit to a weighted combination of monthly gravity fields generated by different analysis centres. The monthly gravity fields models are generated based on GRACE-FO data, so they are capable of accurately catching up the recent changes in the gravity field. These models improve the operational orbit results significantly. Since these fitted signal models (FSM) only cover the GRACE-FO period they are not suitable for consistent reprocessing of entire mission times beyond 2018. In order to support such reprocessing activities an additional COST-G FSM has been generated covering the GRACE and GRACE-FO period. The use of the COST-G products has been proposed to substitute the current EIGEN-GRGS-RL04 mean gravity field model within the Copernicus Precise Orbit Determination (CPOD) Service. Based on limited reprocessing campaigns (from 2019 onwards) of Sentinel-3 A&B using both geopotentials (EIGEN and COST-G), it has shown that the COST-G FSMs represent improvements on the orbital accuracy and yields smaller dispersion of empirical accelerations.Thanks to the recent availability of a new full COST-G FSM covering the GRACE and GRACE-FO period, the present work will extend this analysis to the Sentinel-1, -2 and -6 missions as well, including the full mission (e.g., from 2014 in the case of Sentinel-1A), to confirm the potential benefits of COST-G FSMs.It is worth mentioning that this analysis will be performed with FocusPOD, a new GMV state-of-the-art POD SW.
Multi-scale remote sensing and modeling for estimating liquid water content and LAPs on snow in the European Alps
Authors: Ravasio Claudia , Garzonio Roberto , Di Mauro Biagio , Colombo Roberto
Published: February 2023

The spectral reflectance of snow and ice varies widely depending on several quantities related (1) to the local environmental variables, such as the solar zenith angle and the surface slope, (2) to the physical properties of the snow, such as the grain size and the snow liquid content, and (3) to the presence of light-absorbing particles (LAPs).  Different absorption features are displayed in snow spectra. In particular, the absorption at 1030 nm has been exploited for estimating the grain effective radius of snow both from remote and proximal sensing data (Dozier et al., 2009, Garzonio et al., 2018). This absorption feature has been also used for the retrieval of the liquid water content (LWC) of surface snow since it is characterized by a shift toward shorter wavelengths when LWC increases (Green et al., 2006). Taking benefit of this spectral shift of the absorption feature, we applied a continuum removal approach to obtain both the grain equivalent radius and the LWC value. Furthermore, the accumulation of LAPs, such as dust, black carbon, volcanic ash, and pigmented snow algae on the snowpack albedo increases the absorption of solar radiation and induces a positive surface radiative forcing, enhancing the surface melting.In this contribution, we show a retrieval algorithm to estimate the variables of snow (i.e., snow grain size, snow water equivalent, LAPs concentration) by using the openly available radiative transfer model BioSnicar (Bio-optical Snow, Ice, and Aerosol Radiative model) to simulate the spectral albedo of snow and the absorption of solar light in the snowpack. We present data from two experimental sites located in the Eastern Alps (Stelvio Pass and Brenta Dolomites) collected using a Spectral Evolution spectroradiometer. Measured variables of snow with a Snow Sensor device were compared with those estimated from BioSnicar simulations. Moreover, the impurities content in snow samples collected will be analyzed in a laboratory to better constrain modeling results. Remote sensing is a fundamental tool for characterizing snow cover properties, from the accumulation of LAPs to the wet/dry state of the snow, and the use of satellite sensors (e.g. PRISMA) opens the possibility for monitoring their spatial and temporal variability. This may have an important impact on snow hydrology studies, mainly for monitoring snow melting and improving the management of freshwater resources in the Alpine environment.
Compositional fidelity of phyla and classes in marine benthic associations
Authors: Kowalewski Michal , Tyler Carrie , Kowalewski Michał
Published: February 2023

This study quantified the fidelity of higher taxa (phyla and classes) using comparisons between live communities and sympatric dead remains (death assemblages) using comprehensive surveys of benthic marine invertebrates from coastal habitats in North Carolina (U.S.A). To evaluate fidelity across multiple higher taxa simultaneously, concurrent live and dead samples were collected in a series of dredges over four field seasons (June 2011, November 2011, May of 2012, and April 2013) in Onslow Bay, North Carolina (U.S.A.). Dredging was conducted at 52 localities, 16 of which were sampled in multiple years, resulting in a total of 220 dredge samples collected from a variety of habitats, depths, and distances from shore. All live invertebrates were identified to the lowest taxonomic level possible (typically species). Encrusting species were excluded. Concurrent with live surveys, two bulk samples of dead material were collected at each locality. The results indicate that while community composition differed between the two assemblages across phyla and classes, these differences were predictable with an overabundance of robust and more preservable groups. In addition, dead molluscs appear to be a robust proxy for all taxa when tracking spatio-temporal patterns and shifts in community structure using a variety of diversity metrics. This suggests that despite filters imposed by differential preservation of taxa and time-averaging, the fossil record is likely to be reliable with respect to relative comparisons of composition and diversity in shallow marine benthic associations. This is consistent with previous work indicating that shallow marine death assemblages can yield robust ecological estimates adequate for assessing pristine ecosystems that existed under natural, pre-anthropogenic conditions.
The role of magma supply in fragmentation of oceanic lithosphere
Authors: Pusok Adina E. , Li Yuan , Katz Richard F. , Davis Tim , May Dave A.
Published: February 2023

Observations suggest that the oceanic lithosphere is shaped by dike intrusions and faulting in proportions that depend on the spreading rate (Carbotte et al., 2016). Yet it remains unclear how the interplay between magmatism and faulting during seafloor spreading affects mid-ocean ridge (MOR) axial morphology, fault spacing, and the pattern of abyssal hills (Buck et al., 2005, Huybers et al., 2022). Here we present two-phase flow numerical models of oceanic lithosphere extension that reconcile the nonlinear brittle behaviour of the lithosphere with mantle melting and magma transport through the lithosphere. Fast-spreading ridges show symmetric normal faulting and axial highs, while slow-spreading ridges show an asymmetric fault pattern and axial valleys. Previous work has focused on explaining the MOR fault pattern by tectonic or magmatic-induced deformation. In the first scenario, faults result from tectonic stretching of the thin axial lithosphere during amagmatic periods (Forsyth 1992), while in the second scenario, dike-injection may create stresses that activate extensional faults (Carbotte et al., 2016). Current state-of-the-art models (i.e., Buck et al., 2005) use a single-phase formulation for the deformation of oceanic lithosphere in which a prescribed axial dike may accommodate both magmatic and tectonic extension. In these models, the fault pattern depends on M – the fraction of plate separation rate that is accommodated by magmatic dike opening. While M-models are able to explain a number of observations, M represents a simple parameterization of complex fracture dynamics of sills, dikes, and faults. In particular, M-value models neglect fault–dike interaction and other modes of melt transport and emplacement in the lithosphere (Keller et al., 2013). Here we build a 2-D oceanic lithosphere extension model that incorporates a new poro- viscoelastic–viscoplastic theory with a free surface (Li et al., in review) to robustly simulate plastic representations of dikes and faults in a two-phase magma/rock system. We hypothesise that magma supply controls the pattern of dike–fault interaction in oceanic extension settings. We present simplified model problems to compare results with those from M-value models. These enable us to address the significance of M in terms of fundamental magma and lithospheric processes. We then focus on development of fault patterns, magma pathways and crustal production at fast-/slow-spreading ridges. ReferencesBuck et al., 2005, Nature, doi:10.1038/nature03358.Carbotte et al., 2016, Geol. Soc. London, doi:10.1144/SP420.Forsyth, 1992, Geology, doi:10.1130/0091-7613(1992)020<0027:FEALAN>2.3.CO;2.Huybers et al., 2022, PNAS, doi:10.1073/pnas.2204761119.Keller et al., 2013, GJI, doi:10.1093/gji/ggt306.Li, Y., Pusok, A., Davis, T., May, D., and Katz, R., (in review). Continuum approximation of dyking with a theory for poro-viscoelastic–viscoplastic deformation, GJI.
The use of high resolution electrical resistivity tomography (ERT) and mechanistic hydrological models to increase the efficiency of the wáter applied by irrigation.
Authors: Cabrera Daniel , Faundez Carlos , Diaz Pablo
Published: February 2023

To improve the efficiency of irrigation water application it is necessary to understand 3 important aspects. The depth of wetting reached by each irrigation episode, the overlap between irrigation emitters and the depth where the largest root volume is found. The joint use of electrical resistivity tomography (ERT) with mechanistic hydrological model allows establishing an appropriate irrigation schedule for the particular condition of each irrigation sector, considering aspects for intra-farm soil variability and variations in the root volume of the orchard. For a correct characterization of the existing soil variability in a field, we propose the use of high-resolution ERT (several measurements per hectare) and clustering using k-means for the definition of sites of interest where it is necessary to obtain a petrophysical relationship. (Waxman & Smits, 1968) that allows obtaining the moisture content of the soil from the electrical resistivity of the soil. For the calibration of the mechanistic hydrological model in these same sites, the use of disk infiltrometers measurements is proposed. Through time-lapse ERT measurements in periods between irrigation, it is possible to observe areas of greater water absorption and define areas where there is a greater root volume. Through time-lapse ERT measurements in irrigation episodes, it is possible to determine the depth of wetting reached and use this information to calibrate model parameters of the mechanistic hydrological model. Finally, the use of computer simulations in the defined clusters makes it possible to establish irrigation times and frequencies that ensure a correct overlap between emitters and a wetting depth that reaches the areas of greatest water absorption.
Seasonal variation and source apportionment of Oxygenated (OPAHs) and Nitrated (NPAHs) Polycyclic Aromatic Hydrocarbons in PM2.5 in Ulaanbaatar, Mongolia
Authors: Tseren-Ochir Soyol-Erdene , Erdenebat Iderkhangai , Tumurbat Urangoo , Lee Ji Yi , Natsagdorj Amgalan , Kim Youngpyu
Published: February 2023

Nitrogen and oxygen containing polycyclic aromatic hydrocarbons (NPAHs and OPAHs) are the most dangerous substances for public health and are of increasing interest due to their high toxicity and oxidative properties. Ulaanbaatar, the capital city of Mongolia, has occasionally been considered the most polluted city in the world. The high emissions from various anthropogenic sources of pollutants coupled with unique weather and geographical conditions lead to the formation of haze over the city in winter. The main purpose of this study is to determine the concentration, main sources and seasonal changes of nitrogen and oxygen containing polycyclic aromatic compounds (Oxygenated PAHs and Nitro-PAHs) in atmospheric fine inhalable particulate matter (PM2.5) in Ulaanbaatar city and to compare it with other big cities in East Asia in order to define their risk to human health. Samples were taken in winter (December 2020 and January 2021) and summer (June 2021) and the concentration of 12 types of OPAHs and 8 types of NPAHs were analyzed by Gas Chromatography/Mass Spectrometry (GC/MS).  As a result, the mean concentration of OPAHs in atmospheric PM2.5 particles in Ulaanbaatar is 21.5 and 35.3 times higher than that in Seoul, Korea in winter and summer, respectively. While the concentration of NPAHs was 5.1 times higher in winter and 11.2 times higher in summer than that in Seoul. Major sources and their contributions of NPAHs and OPAHs in atmospheric PM2.5 in Ulaanbaatar were identified based on correlation analysis and Positive Matrix Factorization (PMF) modeling.
Turbulent dispersion of artificial SO2 puffs in the PBL from tomographic reconstructions of the concentration
Authors: Pisso Ignacio , Cassiani Massimo , Kylling Arve , Stebel Kerstin , Schmidbauer Norbert , Stohl Andreas , Dinger Anna Solvejg , Ardeshiri Hamidreza , Park Soon-Young
Published: February 2023

Tomographic 3D reconstructions of artificial puff releases of SO2 were obtained from 2D images taken with UV cameras.  These novel 3D reconstructions provide information on the distribution of concentration from a unique experimaental campaign dataset collected in Rena, Norway. The numerical solutions of the inverse problem of obtaining 3D reconstruction form 2D images were addressed with algebraic methods. Preliminary turbulence analysis of the puff concentration pdf, spatial moments, and 2-point statistics are presented. The experimentally obtained concentration pdf of a puff can be compared with different statistical models found in the literature. The time series of the puff spatial moments are obtained from the 3D concentration field directly in relative coordinates from observations. The distance-neighbour function can also be estimated directly from the 3d puff concentrations. The time series of 3D reconstructions of puffs entail promising posibilities for improving physical parametrizations in numerical dispersion models.
GEOTEK: Extracting Marine Geological Data from Publications
Authors: Suryani Muhammad Asif , Beth Christian , Wallmann Klaus , Renz Matthias
Published: February 2023

In Marine Geology, scientists persistently perform extensive experiments to measure diverse features across the globe, hence to estimate environmental changes. For example, Mass Accumulation Rate (MAR) and Sedimentation Rate (SR) are measured by marine geologists at various oceanographic locations and are largely reported in research publications but have not been compiled in any central database. Furthermore, every MAR and SR observation normally carries i) exact locational information (Longitude and Latitude), ii) the method of measurement (stratigraphy, 210Pb), iii) a numerical value and units (2.4 g/m2/yr), iv) temporal feature (e.g. hundred years ago). The contextual information attached to MAR and SR observations is heterogeneous and manual approaches for information extraction from text are infeasible. It is also worth mentioning that MAR and SR are not denoted in standard international (SI) units.We propose the comprehensive end-to-end framework GEOTEK (Geological Text to Knowledge) to extract targeted information from marine geology publications. The proposed framework comprises three modules. The first module carries a document relevance model alongside a PDF extractor, capable of filtering relevant sources using metadata, and the extraction module extracts text, tables, and metadata respectively. The second module mainly comprises of two information extractors, namely Geo-Quantities and Geo-Spacy, particularly trained on text from the Marine Geology domain. Geo-Quantities is capable of extracting relevant numerical information from the text and covers more than 100 unit variants for MAR and SR, while Geo-Spacy extracts a set of relevant named entities as well as locational entities, which are further processed to obtain respective geocode boundaries. The third module, the Heterogeneous Information Linking module (HIL), processes exact spatial information from tables and captions and forms links to the previously extracted measurements. Finally, the all-linked information is populated in an interactive map view.
Analysis of proxy response and sensitivities in a coupled general circulation model
Authors: Ragone Francesco , Bastiaansen Robbin , Lembo Valerio , Lucarini Valerio
Published: February 2023

In the analysis and interpretation of climate data, both from model simulations and observations, it is often of interest to establish relations between the responses of different observables to a global forcing. This problem in its generality is relevant in the context of the identification of emergent constraints for the climate system, detection and attribution studies, and the analysis of proxy data. Recently it has been discussed how in linear response theory it is possible to build proxy response operators, that allow to use the response of one observable to a forcing to predict the response of another observable. The spectral properties of the proxy response functions determine then the properties of statistical predictability at different time scales for the pair of observables. The skill and feasibility of this approach for complex climate data has however not been fully tested yet. In this work we analyse the properties of proxy response in experiments with the coupled general circulation model MPI-ESM v.1.2. We consider ensemble simulations of abrupt CO2 doubling and 1% per year CO2 increase scenarios. We study the response of different atmospheric and oceanic variables, and we compute proxy response functions for different pairs of observables. We analyse the predictive power for the different cases, and interpret differences in skills in terms of causal relations among observables. We also study the relation between statistical variability and long term sensitivity, and we discuss differences between ensemble and internal variability in unforced and forced states. We then link our results to the discussion on the interpretation of emergent constraints in climate change simulations.
On Artificial Intelligence-based emulators of physical models to forecast the evolution of lava flows
Authors: Zago Vito , Amato Eleonora , Cariello Simona , Corradino Claudia , Torrisi Federica , Del Negro Ciro
Published: February 2023

Timely forecasting of the evolution of lava flows is one of the key elements for assessing volcanic hazards. Lava flows are among the main hazardous phenomena during an effusive eruption, due to the possibility to reach urban areas and cause damage to infrastructure. Physical-mathematical models can be used to estimate the dynamics of a fluid or the fluid-solid interactions, in particular for the case of lava flows. However, high fidelity models require long execution times and large computational resources. Recently, artificial intelligence (AI) has been adopted to emulate physics-based models and deliver similar results, speeding up the simulations. We will discuss the possibility to use AI-based approaches to emulate highly complex numerical models used to simulate the spatio-temporal evolution of lava flows. Analyzing and treating the formal mathematical aspects of the models under analysis, we will verify and validate the models using test cases associated with the main features of lavas, discussing the accuracy and the performance offered by the two approaches.
Local earthquake recordings using Distributed Acoustic Sensing (DAS) at BFO
Authors: Karamzadeh Toularoud Nasim , Gao Ya-Jian , Azzola Jérôme , Forbriger Thomas , Widmer-Schnidrig Rudolf , Gaucher Emmanuel , Rietbrock Andreas
Published: February 2023

The application of distributed acoustic sensing (DAS) in seismology is rapidly expanding due to its ability to perform a large number of high-density measurements, i.e., distributed sensing, without using many point sensors, which is cost-effective. DAS application includes vertical seismic profiling, microseismic measurements, and hydraulic fracturing monitoring and mainly focuses on the event detection capability of  DAS data. Febus optics DAS interrogator (A1-R) is continuously running at German Black Forest Observatory (BFO) since May 2021, recording RAW data (selectively stored) or strain-rate data (continuously stored). Our study is in the experimental phase and focuses on testing basic concepts of DAS data, i.e., the effect of gauge-length on the amplitude of measurement and comparing the amplitude of DAS with other seismological sensors such as strain-meter array and a STS2 broadband sensor as well as synthetic simulations. Such comparison is performed using background noise characteristics (power spectral density) and examples of local and regional events that are detectable at the BFO site. In this study, we show examples of strain rate measurements related to local earthquakes recorded by horizontal fiber optic cables, employing two different DAS interrogators, cable types and coupling of the cables to the ground. We compared simultaneous recordings using Febus A1 DAS interrogator and OptoDAS by Febus optic and Alcatel Submarine Networks (ASN), respectively, and, concluded about the frequency and gauge-length dependent sensitivity of recordings in two cases. In addition, we compare the amplitude of DAS recordings, for example of local earthquakes, with the synthetic strain simulated  at lower frequency bands using the spectral-element method (Salvus) based on 3D media and analytic approach (Qseis) for 1D model.  
Detailed look at the temporal correlation between hard X-ray flare and type III radio bursts
Authors: Bhunia Shilpi , Hayes Laura , Maloney Shane , Gallagher Peter
Published: February 2023

It is well known that flare-accelerated electrons can produce both hard X-ray (HXR) emission and Type-III radio bursts. The HXR emission is produced by the accelerated electrons propagating towards the chromosphere where they deposit their energy while Type-III radio bursts are produced by the accelerated electron beams traveling towards the outer solar atmosphere. Hence a temporal correlation between these two kinds of emission may imply a common origin of the accelerated electrons providing insight into the acceleration process, and allows us to connect electrons at the Sun to those in the heliosphere. On 2022-Nov-11 11:30 - 12:00 UT, the Spectrometer Telescope for Imaging X-rays (STIX) on Solar Orbiter observed a highly energetic flare event with an excellent time resolution of 0.5 s. Simultaneously there were observations of multiple coronal and interplanetary Type-III radio bursts from several instruments such as I-LOFAR, WIND/WAVES, NDA and ORFEES. I-LOFAR provides high-sensitivity imaging spectroscopy in the range of ~10-240 MHz with a time resolution of 1.31 ms and a frequency resolution of 195 kHz. We examine the temporal correlation between the X-ray and radio time series and discuss the relationship between the two and what it implies   about the origin of the electron populations producing these two kinds of radiation.
The SOMMIT Project: SUstainable Management of soil Organic Matter to MItigate Trade-offs between C sequestration and nitrous oxide, methane and nitrate losses
Authors: Diaz-Pines Eugenio , Keuper Frida , Bastida Felipe , Bregaglio Simone , Cayuela Maria Luz , Di Bene Claudia , Ferchaud Fabien , Ferrara Rossana , Fiore Angela , Léonard Joel , Maenhout Peter , Mihelič Rok , O´Toole Adam , Suhadolc Marjetka , Syp Alina , Testani Elena , Valkama Elena , Lagomarsino Alessandra
Published: February 2023

Within the context of climate change there is increasing focus on the implementation of agricultural practices which contribute to soil C sequestration (Cseq) to mitigate rising atmospheric CO2 levels. The agricultural sector is, however, also the largest global contributor to anthropogenic non-CO2 GHGs. N2O and CH4 emissions contribute substantially to the Earth’s radiative forcing and even small impacts on their fluxes could hamper climate change mitigation efforts. While it is known that Soil Management Strategies (SMS) aimed at increasing Cseq in agricultural soils also affect soil N2O and CH4 fluxes and N losses through leaching, data and knowledge are still fragmented. Thus, a Europe-wide policy approach to the resulting trade-offs is urgently needed, given the high global warming potential of N2O. Mitigation effects of agricultural practices enhancing Cseq can largely be offset if N2O emissions increase but SMS enhancing Cseq and reducing non-CO2 GHG emissions imply a “double-win” situation for climate change mitigation. Integrated, coupled investigations are still scarce, with only a few studies addressing trade-offs comprehensively.Overall, the ∑OMMIT project evaluates trade-offs and synergies between soil C sequestration, nitrous oxide, methane and nitrate losses as affected by soil management options aimed at increasing soil C storage. The integrated and interdisciplinary approach will address the main pedo-climatic conditions and farming systems in Europe, through 1) synthesis and meta-analysis of available literature and data; 2) targeted, novel measurements on key long-term experiments; and 3) simulation of long-term agro-ecological system responses to contrasting management options. Moreover, obtained data will be synthesized through a fuzzy-expert system which will allow for 4) evidence-based identification of optimal strategies for mitigation of trade-offs, and 5) effective stakeholders’ involvement. Overall, we aim at increasing our understanding on the mechanisms and driving forces affecting N2O and CH4 fluxes. Our approach works from different perspectives, allowing a cross-validation on the observed interactions and feedbacks. Here, the current status of the ∑OMMIT project will be presented. We will show the most important results obtained so far and will discuss the implications for soil management strategies in the agricultural European context.
Finding governing PDEs of quasistatic fault slip and basal slip evolution from (synthetic) slip rate and shear traction data.
Authors: Biswas Pulak , Ray Sohom
Published: February 2023

Mechanical models of slip development on geological faults and basal slip development in landslide or ice-sheets generally consider interfacial strength to be frictional and deformation of the surrounding medium to be elastic. The frictional strength is usually considered as sliding rate- and state-dependent. Their combination, elastic deformation due to differential slip and rate-state frictional strength, leads to nonlinear partial differential equations (PDEs) that govern the spatio-temporal evolution of slip. Here, we investigate how (synthetic) data on fault slip rate and traction can find the system of PDEs that governs fault slip development during the aseismic rupture phase and the slip instability phase. We first prepare (synthetic) data sets by numerically solving the forward problem of slip rate and fault shear stress evolution during a seismic cycle. We now identify the physical variables, for example, slip rate or frictional state variable, and apply nonlinearity identification algorithms within different time durations. We show that the nonlinearity identification algorithms can find the terms of the PDE that governs the slip rate evolution during the aseismic rupture phase and subsequent instability phase.In particular, we use nonlinear dynamics identification algorithms (e.g., SINDy, Brunton et al., 2016) where we solve a regression problem, Ax=y. Here, y is the time derivative of the variable of interest, for example, slip rate. A is a large matrix (library) with all possible candidate functions that may appear in the slip rate evolution PDE. The entries in x, to be solved for, are coefficients corresponding to each library function in matrix A. We update A according to the solutions x so that A's column space can span the dynamics we seek to find. To find the suitable column space for A, we encourage sparse solutions for x, suggesting that only a few columns in matrix A are dominant, leading to a parsimonious representation of the governing PDE. We show that the algorithm successfully recovers the PDE governing quasi-static fault slip and basal slip evolution. Additionally, we could also find the frictional parameter, for example, a/b, where a and b, respectively, are the magnitudes that control direct and evolution effects. Moreover, the algorithm can also determine whether the associated state variable evolves as aging- or slip-law types or their combination. Further, with the data set prepared from distinct initial conditions, we show that the nonlinear dynamics identification algorithm can also determine the problem parameters’ spatial distributions (heterogeneities) from fault slip rate and shear stress data. 
Peri-Urban Green Belts: Introduction of Decentralized and Coupled Citizen Science and Nature-Based Sanitation Solutions in the Context of Urban Transformation
Authors: Loghmani Khouzani Seyed Taha
Published: February 2023

Unprecedented famine and rocketing food prices are expected to grow as the emerging shocks continue to reshape our world. Lying at the interface of the resource nexus, the agri-food systems are identified as a primary consumer of global freshwater resources and the main contributor to food security. As a result of external shocks, limitations on human activities have resulted in unexpected disturbances in the global agri-food chain, decreasing the functionality and efficiency of agri-food systems and raising the alarm for a need to transform our food systems. Candidating Peri-urban Green Belts as agents of transformation, this research investigates the potential of adding decentralized and coupled Citizen Science and Nature-Based Sanitation Solutions (CS-NBSS) to cause a transformation in urban and peri-urban contexts. Utilizing existing knowledge from researchers and practitioners in the field, alternative NBSs have been identified which interconnect the WASH sector to the food sector, e.g., evapotranspiration tanks (TEvap). We hypothesize that adding such systems to the existing grey infrastructure can increase food and urban resilience and promote marginalized communities' participation in urban governance. CS and NBS have been prominently highlighted in literature due to their merits in constructing and promoting sustainable attitudes and contexts, causing the underlying systems to behave sustainably. Considering the vital role of governance in steering the technical, economic, social, and environmental dimensions of transformation, a critical question remains on how to go beyond existing public policy research on the participation variable. Current research primarily emphasizes ‘what is (status quo) and what needs to be’ rather than proposing methodological approaches towards the latter. With this objective in mind and focused on the food and WASH sector as primary concerns of peri-urban communities, their local governments, and academia, this project will apply mixed-method research to collaboratively design, implement, monitor, and evaluate CS-NBSS living lab experiences in three case studies, incorporating and assessing the effect of such systems on the participation variable, food, and urban resilience, as well as their potential to cause a transformation.
Paleohygrometry and reconstruction of lake evaporation history based on compound-specific hydrogen and oxygen isotope analyses of biomarkers – principle of the coupled isotope approach, advances and limitations
Authors: Zech Michael , Hepp Johannes , Tuthorn Mario , Lemma Bruk , Bittner Lucas , Zech Roland , Rozanski Kazimierz , Glaser Bruno
Published: February 2023

The oxygen and hydrogen isotopic composition δ2H and δ18O of leaf and lake water reflects the isotopic composition of source water/precipitation modified by evapo(transpi)rative enrichment. This later enrichment can be illustrated and quantified using δ2H- δ18O diagrams and the deuterium-excess. The enrichment of leaf water thereby depends primarily on relative air humidity (RH) and can be investigated using biomarkers being produced in leaves. The enrichment of lake water depends on lake evaporation and can be investigated using biomarkers being produced by aquatic macrophytes or algae. Provided that unambiguous terrestrial and aquatic biomarkers can be identified in lake sediments, the coupling of δ2H and δ18O hence allows reconstructing RH (paleohygrometry approach) and lake evaporation history. In our contribution, we discuss the potential, the advances and the limitation of the coupled isotope approach based on leaf wax-derived n-alkane and hemicellulose-derived sugar biomarkers (δ2Hn-alkanes-  δ18Osugars). ReferencesHepp, J., Mayr, C., Rozanski, K., Schäfer, I., Tuthorn, M., Glaser, B., Juchelka, D., Stichler, W., Zech, R. and Zech, M., 2021. Validation of a coupled δ2Hn-alkane-δ18Osugar paleohygrometer approach based on a climate chamber experiment. Biogeosciences 18, 5363-5380.Hepp, J., Wüthrich, L., Bromm, T., Bliedtner, M., Schäfer, I. K., Glaser, B., Rozanski, K., Sirocko, F., Zech, R., and Zech, M., 2019. How dry was the Younger Dryas? Evidence from a coupled δ2H-δ18O biomarker paleohygrometer applied to the Lake Gemündener Maar sediments, Western Eifel, Germany, Climate of the Past 15, 713-733.Zech, M., Tuthorn, M., Detsch, F., Rozanski, K., Zech, R., Zöller, L., Zech, W. and Glaser, B., 2013. A 220 ka terrestrial δ18O and deuterium excess biomarker record from an eolian permafrost paleosol sequence, NE-Siberia. Chemical Geology 360-361, 220-230.
Reconciliation of updated greenhouse gas budgets from UNFCCC national inventories and atmospheric inversions
Authors: Deng Zhu , Ciais Philippe , Hu Liting , Saunois Marielle , Chevallier Frédéric , Xiao Lei , Liu Zhu , Zhou Wenwen
Published: February 2023

Assessing and understanding the causes of mismatches between inversion results and inventories is key to future greenhouse gas budget estimates and also a contribution to phase 2 of the REgional Carbon Cycle Assessment and Processes (RECCAP2) initiative. Here, we compare the latest greenhouse gas budgets from the updated National Greenhouse Gas Inventories (NGHGIs) submitted to the United Nations Framework Convention on Climate Change (UNFCCC) and from the updated atmospheric inversions based on both in-situ and satellite observations. We compile the latest global harmonized NGHGI database for all countries according to the updated national communications (NCs) and biennial update reports (BURs) by the end of the year 2022. With the updated global atmospheric inversion results of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) produced by the Global Carbon Project, we adjust the inversion results of all countries for comparison, considering lateral river transfer processes and trade in crop and timber products, as well as the role of carbon sequestration in unmanaged land not considered by NGHGI, and compare them with greenhouse gas budgets in national inventories. The results show that there is a good consistency in net land CO2 flux based on the global in-situ network and that using satellite CO2 retrievals over tropical countries like Congo, Brazil, Peru, South Africa, and so on. For CH4, while the uncertainties of inversion results have been reduced in the updated global inversion ensembles compared to the previous ones, it seems that oil and gas-extracting countries like Saudi Arabia and Qatar report lower emissions compared to those estimated by inversions. This study is a reapplication of the methodologies developed by our previous study, which are confirmed and could be applied regularly and show how inversion could be used systematically in the future to support the assessment and improve the inventory of the Paris Agreement.
Limits of large deviation theory in predicting transition paths of climate tipping events
Authors: Börner Reyk , Deeley Ryan , Nesbitt Calvin , Römer Raphael , Grafke Tobias , Feudel Ulrike , Lucarini Valerio
Published: February 2023

Following Hasselmann’s ansatz, the climate system may be viewed as a multistable dynamical system internally driven by noise. Its long-term evolution will then feature noise-induced critical transitions between the competing attracting states. In the weak-noise limit, large deviation theory allows predicting the transition rate and most probable transition path of these tipping events. However, the limit of zero noise is never obtained in reality. In this work we show that, even for weak finite noise, sample transition paths may disagree with the large deviation prediction – the minimum action path, or instanton – if multiple timescales are at play. We illustrate this behavior in selected box models of the bistable Atlantic Meridional Overturning Circulation (AMOC), where different restoring times of temperature and salinity induce a fast-slow characteristic. While the minimum action path generally crosses the basin boundary at a saddle point, we demonstrate cases in which ensembles of sample transition paths cross far away from the saddle. We discuss the conditions for saddle avoidance and relate this to the flatness of the quasipotential, a central object of large deviation theory. We further probe the vicinity of the weak-noise limit by applying a pathspace method that generates transition samples for arbitrarily weak noise. Our results highlight that predictions by large deviation theory must be treated cautiously in multiscale dynamical systems.