bluuebunny/crossref_metadata_2025 huggingface dataset:
The Warm Winter Paradox in the mid-Pliocene Warm Period - a focus on model parameterisations.
Authors: Tindall Julia , Haywood Alan , Valdes Paul
Published: February 2023

Modelling results from PlioMIP2 (Pliocene Model Intercomparison Project Phase 2) are in strong disagreement with terrestrial proxy data over the high latitudes for the winter season.  This disagreement is large:  models simulate winter temperatures ~20°C cooler than the data suggests.  We term this the ‘warm winter paradox’.We have shown that the warm winter paradox cannot be easily resolved.  For example, changing model boundary conditions to account for orbital and CO2 uncertainty have only a small effect on winter temperatures.Here we use the Hadley Centre General Circulation Model, HadCM3, to investigate whether accounting for uncertainties in model parameterisations could improve the model data agreement for the Pliocene winter.  A new set of parameters for HadCM3, which improve model-data agreement for the Eocene, will be used to investigate the Pliocene climate.  We will show that the new parameters in HadCM3 lead to additional winter Pliocene warming at some locations, although a large model-data disagreement remains.   The new model parameters do not improve the Pliocene data-model comparison as much as they do for the Eocene.  This may indicate that finding a single set of parameters capable of producing an optimised simulation of warm climate states in general is not possible, and that further exploration of model parameter uncertainty is warranted; or that the cause of model data disagreements in the high latitudes may be time period specific.   
Multi-tracer tests to disentangle mobile-immobile regions in a highly entropic aquifer
Authors: Brunetti Guglielmo Federico Antonio , Stumpp Christine , Fallico Carmine , Severino Gerardo , De Bartolo Samuele
Published: February 2023

Anomalous transport processes are frequently observed in radial flow to wells in highly heterogeneous aquifers. This is generally related to the presence of preferential flow pathways that bypass the sediment matrix, thus leading to the formation of fast flow channels, whose magnitude depends on the geological entropy of the system. Tracer tests can be effectively combined with laboratory or field-scale experimental campaigns to understand better the interlinkage between heterogeneity and preferential flow, and to distinguish hydraulically active and inactive regions. Despite considerable past research efforts, these mechanisms are only partially understood. To advance the current understanding, we study transport processes in a laboratory-built highly heterogeneous aquifer under radial flow conditions. The experimental device (200 x 200 x 100 cm) consists of 2527 randomly distributed cells (10 x 10 x 5 cm) of 12 different porous mixtures assembled in 7 layers to form a 35 cm-deep aquifer. This particularly design is intended to maximize the geological entropy of the aquifer, which is equipped with 37 piezometers placed in a radial configuration at different distances from the central (pumping) well. Multiple conservative tracer tests were conducted by injecting a mixture of deuterated water (D2O) and Potassium Bromide (KBr) into different piezometers, and then by analysing the resulting Breakthrough Curves (BTCs) at the central pumping well. BTCs reveals features peculiar of anomalous transport, such as non-symmetry, early peaks and tailing, which depend on the injecting location. This, jointly with the incomplete mass recovery after 48 hours, suggests the simultaneous presence of fast flow in highly conductive regions, which exchange mass with quasi-immobile portions of the aquifer. By dealing with tests individually, it is seen that curves for the two tracers have a similar trend, with almost perfect overlap in the part before the peaks. Differences in the tailing of the BTCs between the two tracers, that exhibit different molecular diffusion coefficients, indicate the importance of diffusion mechanism taking place in the porous matrix.
An outlook on the state of soil health research
Authors: Terribile Fabio , Basile Angelo , Bonfante Antonello
Published: February 2023

Looking to research databases (e.g. WoS), it is self-evident that (i) in the last 5 years there is an exponential increase of papers having a Soil Health (SH) focus (« soil health » in the title), (ii) most of these papers are produced after USA and Asian countries while Europe is well behind (less than 1/3 of USA production), (iii) most of this scientific production is sustained by public authorities (e.g. USDA in USA).
It is also well known that Soil health has become a key topic for policy due to the contribution of the EU Soil Mission. Thanks to this effort, in EU we have an important direction towards its definition since Soil Health needs to deliver a specific list of ecosystem services (after             the Soil Thematic Strategy policy instrument).
Then how to measure soil health? If we look the scientific work on SH, there are plenty of indicators based on soil parameters, soil properties and soil functions, but almost no or minimal ecosystem services evaluations.
The most widespread approaches in scientific literature is to evaluate SH are based on empirical approaches. But if SH has to evaluate ecosystem services and if SH requires approaches easy to be transferable to new areas then it is of paramount importance to stress the need and importance of mechanistic models versus empiric models. In fact decades of research have proved that empirical approaches require much larger calibration dataset and they have also much lower transferability as compared to mechanistic models. Consequently, not all models are the same especially in view of their implementation in operational Decision Support Systems.
This approach it will enable adaptation to every specific region and their related ecosystem services.
What is now required from the research community are: (i) Operational procedures to assess multiscale ecosystem services and the role of soils in contributing to such services and (ii) effective way to communicate results to end-users and stakeholders.
  
Mantle controls on geodynamic processes and their surface expressions: a global approach
Authors: Arnould Maëlis , Manjón-Cabeza Córdoba Antonio , Rolf Tobias
Published: February 2023

It is well-established that the mantle exerts a strong control on the geodynamic processes and their expressions observed at the surface. One of the key components in mantle-surface interaction is rheology, yet, the details of this rheological coupling remain not well understood. This is particularly true for large to global scales, which are difficult to assess in the field or in the lab. For instance, rheological inheritance is thought to influence the onset location of plate boundaries and their subsequent evolution. But the originating physical processes and timescales over which such rheological inheritance applies are still debated. Moreover, differences in the rheological coupling between mantle and surface are expected to change first-order surface observables, such as topography.Here, we use numerical geodynamic models of whole-mantle convection to test the sensitivity of surface tectonics to different rheological assumptions, for instance in terms of deformation mechanisms at play and rheological inheritance. We show that the self-consistent generation of plate tectonics from mantle convection is altered by the use of a composite rheology (with co-existing diffusion and dislocation creep), by the consideration of mantle grain-size evolution, as well as by simple parameterisations of rheological memory such as strain-weakening. Using a set of quantitative diagnostics, we also demonstrate how such rheological complexities affect surface topography.
Study of a dayside magnetopause reconnection event detected by MMS related to a large-scale solar wind perturbation and magnetospheric cold ions
Authors: Baraka Mohammed , Le Contel Olivier , Canu Patrick , Alqeeq Soboh , Akhavan-Tafti Mojtaba , Retino Alessandro , Chust Thomas , Cazzola Emanuele , Fontaine Dominique , Toledo-Redondo Sergio , Dargent Jeremy , Cozzani Giulia , Norgren Cecilia ,   MMS Team
Published: February 2023

Magnetic reconnection is a fundamental process that is ubiquitous in the universe and allows the conversion of magnetic field energy into heating and acceleration of plasma. It is responsible for the dominant transport of plasma, momentum, and energy across the magnetopause from the solar wind into the Earth's magnetosphere. The present study reports on a magnetic reconnection event detected by the Magnetospheric Multiscale mission (MMS) on 21 October 2015 around 04:40 UT far from the diffusion regions and related to a large-scale solar wind (SW) perturbation impacting the Earth’s magnetosphere. Based on OMNI data, the event impacting the Earth’s magnetosphere is ahead of weak Stream Interacting Region (SIR) (SW beta≈7 and Alfvénic Mach number≈15) where the averaged density of solar wind is about ~20 cm-3 (compared with average SW density ~3-10 cm-3). On one hand, the magnetosheath (MSH) density measured by MMS just after the crossing of the magnetosphere separatrix layer (identified by the large decrease of energetic electrons fluxes) is very large ~95 cm-3 (compared with average MSH density ~20 cm-3). In such a condition, we show that the current density at this separatrix is dominated by the ion diamagnetic current. On the other hand, cold ions are detected close to the magnetic reconnection separatrix layer on the magnetosphere side. Their origin and impact on the ongoing reconnection process are investigated/discussed. The drifting cold ions and the presence of a guide field have significant effects on the orientation of the electric field normal to the magnetopause.
Landslide movement pattern revealed by temporal and spatial monitoring: A dip slope case in northern Taiwan
Authors: Tseng Chia-Han , Chan Yu-Chang , Jeng Ching-Jiang , Rau Ruei-Juin , Hsieh Yu-Chung
Published: February 2023

A natural hillslope developing into a landslide shows ground cracks and topographic deformation. Geomorphological and subsurface investigations using appropriate methodology are essential to understand the failure mechanisms and stability of a hillslope. A dip slope in sedimentary rock in northern Taiwan has been observed to have a potential landslide hazard for the development of ground cracks and persistent deformation of local buildings and facilities on the slope. To monitor the movement of the dip slope and then understand its movement pattern, 144 ground monitoring points was set in 2001, and its coordinates were measured using conventional traverse surveying twice a year until 2017. In addition, 6-year surficial surveying results as time series of displacements and velocity field are revealed by each GPS station on the slope surface. The long-term surveying results point out different displacement patterns of the dip slope depending on rainfall duration and amount. The surficial surveying results are presented as a time series of displacements with constraints of geometry and distribution of ground cracks and underground observations. The long-term surveying results reveal multiple potential sliding blocks within the Huafan University campus. A model of landslide movement with a listric sliding surface is proposed. Finally, the continuous GPS stations show the average velocity of 0.396~0.528 x 10-7 mm/sec, being classified as “Extremely slow” in the global “velocity scale of landslides” proposed by Cruden and Varnes in 1996. The long-term surface monitoring of a potential landslide slope in this study provides a reliable and economical way to understand the mechanism of movement behavior of the slope and evaluate slope stability.
Measures of correlation length at Earth’s quasi-parallel and quasi-perpendicular bow shock
Authors: Plank James , Gingell Imogen
Published: February 2023

Turbulent plasmas such as the solar wind and the magnetosheath exhibit an energy cascade which is present across a broad range of scales, from the stirring scale at which energy is injected, down to the smallest scales where energy is dissipated through processes such as reconnection and wave-particle interactions. Recent observations of Earth’s bow shock reveal the presence of a disordered or turbulent transition region which exhibits some features of turbulent dissipation, such as reconnecting current sheets. Understanding the variations in the origin and character of these disordered fluctuations addresses open questions such as how disordered or turbulent fluctuations in the bow shock and magnetosheath are related, and how quickly magnetosheath turbulence arises from bow shock processes. Here, we present two case studies of bow shock crossings observed by Magnetospheric Multiscale (MMS), one quasi-perpendicular and one quasi-parallel. Using high-cadence, combined search-coil and fluxgate magnetometer data, we measure changes in correlation lengths of the magnetic field through three regions: the upstream (solar wind), shock transition region, and downstream (magnetosheath). The influence of the discontinuous shock ramp is reduced using high-pass filters with variable cut-off frequencies. We find that correlation lengths are higher on the solar wind side of the shock, reducing to around 20 ion inertial lengths in the magnetosheath for both the quasi-parallel and the quasi-perpendicular shocks. We also discuss implications of the observed evolution of the correlation length to bow shock and magnetosheath processes.
3D geological modeling of the blind thrust system activated during the November 2022 Pesaro offshore seismic sequence (Adriatic sea, Italy).
Authors: Maesano Francesco Emanuele , Buttinelli Mauro , Maffucci Roberta , Toscani Giovanni , Basili Roberto , Bonini Lorenzo , Burrato Pierfrancesco , Fedorik Jakub , Fracassi Umberto , Panara Yuri , Tarabusi Gabriele , Tiberti Mara Monica , Valensise Gianluca , Vallone Roberto , Vannoli Paola
Published: February 2023

The undersea portion of the Northern Apennines is characterized by blind thrust faults running parallel to the Adriatic Sea coastline in northeastern peninsular Italy. These thrusts are buried below a thick cover of syntectonic Quaternary deposits. Their elusive geological signature at shallow depths and the low seismicity associated with them gave rise to diverging interpretations and views concerning the current activity of these thrusts and their earthquake potential.On 9 November 2022, a seismic sequence started with an Mw 5.5 earthquake in the Pesaro Offshore. Hypocentral depth, focal mechanism, and aftershocks location all suggest that the earthquake was generated by one of the outermost thrusts of the Northern Apennines front that was already mapped as a potential seismogenic source in the DISS database (https://diss.ingv.it/diss330/sources.php?ITCS106).We present a 3D reconstruction of the thrust system that caused the Pesaro Offshore seismic sequence obtained through the reinterpretation of publicly available seismic reflection profiles and well logs. The 3D geometry and size of the thrust activated during the seismic sequence suggest that it can also host larger earthquakes. We also present the application of a well-established workflow for calculating the slip rates of this buried thrust already tested in nearby structures. The outcomes of this study represent a step forward for earthquake and tsunami hazard models, the study of the seismic source, the enhancement of earthquake location by mix and match of seismological and geological independent data, and the expected kinematics of future potential earthquake ruptures.These results are particularly relevant in offshore areas, where neither surface co-seismic ruptures nor GPS/InSAR deformation data are available in the aftermath of a significant earthquake. In these cases, multichannel seismic reflection profiles represent the only tool to appraise the subsurface structural setting. 
Added value of machine learning in the assimilation of ASCAT observations into the ISBA land surface model
Authors: Corchia Timothée , Bonan Bertrand , Rodriguez-Fernandez Nemesio , Colas Gabriel , Calvet Jean-Christophe
Published: February 2023

In the context of global warming, the frequency and intensity of extreme events such as droughts are increasing, and a better modeling of vegetation response to climate is needed. Monitoring the impact of extreme events on land surfaces involves a number of soil-plant system variables such as soil water content, soil temperature and vegetation leaf area index (LAI). These variables control the carbon, water, and energy land surface fluxes. They can be monitored either by using the unprecedented amount of data from the fleet of Earth observation satellites or by using land surface models. Alternatively, all available sources of information can be combined by assimilating satellite observations into models. The LDAS-Monde Land Data Assimilation System is a tool developed by the Centre National de Recherches Météorologiques (CNRM). It allows the joint assimilation of Advanced SCATterometer (ASCAT) surface soil moisture and Copernicus Global Land service (CGLS) LAI retrievals into the ISBA (Interaction Sol-Biosphère-Atmosphère) land surface model of Meteo-France, with the objective of better representing leaf biomass and root-zone soil moisture. The ASCAT C-band radar backscatter coefficients (σ0) contain information on both surface soil moisture and vegetation and its assimilation could prove beneficial. For this, an observation operator that links σ0 to the ISBA land surface variables is needed. In this work, a method for the assimilation of ASCAT σ0 into ISBA using LDAS-Monde is presented. In a first step, observation operators are built using machine learning. Neural networks (NN) are trained using as inputs modeled soil surface moisture, soil temperature, rainwater interception by leaves and CGLS satellite observations of LAI. Then the observation operators are implemented into LDAS-Monde, making it capable of assimilating the satellite product. The method is implemented over southwestern France, where in situ soil moisture observations are available. It is shown that the assimilation of σ0 alone markedly improves the simulation of LAI and soil moisture in agricultural areas. Results vary from one land cover type to another.
Surface and subsurface mapping of the Flamborough Head Fault Zone to inform groundwater management in the Yorkshire Wolds, UK.
Authors: Vernon Rowan , Burrel Laura , Ford Jon , Haslam Richard , Randles Tom , McCarthy Dave , Woods Mark , Burke Helen
Published: February 2023

The Flamborough Head Fault Zone (FHFZ) is a regionally-significant structural zone in northeast England which dissects the Upper Cretaceous Chalk Group, a 500 m thick limestone succession which is a principle aquifer and main source of water supply in the region. The geometry and physical characteristics of the Chalk succession, including the effects of faulting, influence groundwater flow across the region. Consequently, understanding the architecture of the FHFZ is vital to sustainably managing water resources in this area.The FHFZ marks the southern extent of the Cleveland Basin and the northern margin of the Market Weighton Block and has a complex history of Mesozoic-Cenozoic extension and compression. It is predominantly comprised of east-west trending faults which form a graben that is dissected by north-south trending faults, including the southern extension to the Peak Trough, the Hunmanby Fault. To the west, FHFZ links with the Howardian Fault System and offshore, in the east, it is truncated by the north-south trending Dowsing Fault. The FHFZ is well exposed and described in coastal cliff sections at Flamborough Head but the inland architecture of the faults has hitherto been poorly explored predominantly due to limited inland-exposure.To address this a multi-faceted approach to geological mapping has been undertaken in the region by the British Geological Survey, in collaboration with the Environment Agency and Yorkshire Water Limited. Remote sensing, targeted field mapping, palaeontological analysis, passive seismic and 2D onshore seismic interpretation have been integrated to understand the inland architecture of the FHFZ in unprecedented detail. Combining these techniques has enabled us to bridge the gap between the surface geology and deeper subsurface structure, increase our understanding of the geology of the region and produce an improved conceptual model at a range of depths which will be used to better manage water resources.
Determining the „geothermal reinjection potential” into sedimentary formations using datasets of hydrocarbon exploration
Authors: Markó Ábel , Tóth Marianna , Brehme Maren , Mádl-Szőnyi Judit
Published: February 2023

The so-called Green Transition EU strategy encourages oil businesses to move towards a circular economy and create green energy. The data already collected in the past during hydrocarbon exploration offer enormous possibilities for geothermal reutilization. Revealing this led to the joint project with MOL Plc. to evaluate the geothermal potential for Zala county, Hungary. Although the preliminary geothermal potential of the Zala region (SW Hungary) is assessed to be good, sustainable thermal water use is critical due to the need for reinjection, with only one operating doublet. The study focuses on the geothermal assessment of the siliciclastic Neogene formations.Due to the need for reinjection wells for sustainable thermal water production, the evaluation has to handle the potential injectivity for the same siliciclastic reservoir. However, several injection-related problems are associated with the Neogene (so-called Pannonian) siliciclastic reservoirs in Hungary. Predicting the issues makes it possible to mitigate them, and it contributes to a “reinjection potential” assessment which can be part of the geothermal potential estimation.Based on methodological contribution from previous studies (e.g., Markó et al., 2021), this research considers a variety of problem scales, including regional hydraulics, reservoir scale properties, and local clogging processes. As a next step, in the recent study, we investigate the extension of the reservoir sandstone bodies of the deltaic aquifer. This is done by interpreting 3D seismic volumes by amplitude extraction to detect sand-prone volumes combined with well-logs to delineate the reservoir. The analysis helps to predict where to drill the next reinjection well as well as to evaluate the potential of the existing hydrocarbon wells.The first author was supported, and the research was financed through the KDP-2021 Cooperative Doctoral Programme of the Ministry of Innovation and Technology (Hungary) from the source of the National Research, Development and Innovation Fund, grant number: KDP_2021_ELTE_C1789026. The study was funded by the National Multidisciplinary Laboratory for Climate Change, RRF-2.3.1-21- 2022-00014 project.
Impact of active layer thickening on vertical soil organic matter GHG emissions in a dynamic vegetation model
Authors: Wårlind David , Martín Belda David , Miller Paul A. , Nieradzik Lars , Olin Stefan , Pongrácz Alexandra
Published: February 2023

With climate change happening at a faster rate at high-latitudes than the global average, it is important to understand the warming-induced permafrost thaw effect on high-latitude GHG emissions. As permafrost soils contain nearly half of the global soil C pool a change to active layer depths could substantially increase GHG emissions from the soil and hence the concentrations in the atmosphere. Here we present a version of the dynamic vegetation model LPJ-GUESS updated to include a new multi-layer soil organic matter scheme that makes it possible to simulate organic matter dynamics at all soil depths. Together with improved soil physics, hydrology, and snow representation, this new version of LPJ-GUESS can closely simulate the current best estimates of Arctic soil C at depths (e.g. NCSCDv2.2) making it possible to simulate emissions of CO2, CH4, and N2O as the active layer thickens. We also present preliminary estimates of how the Arctic soil thermodynamics and biogeochemistry could change under different future scenarios, including overshoot scenarios, to see if the Arctic C balance will act as a net source or sink of greenhouse gases.
Estimation of Mangrove Leaf Area Index using Unmanned Aerial Vehicle multispectral imagery
Authors: Elías-Lara Mariana , Rodríguez Jorge , Tu Yu-Hsuan , Blanco-Sacristán Javier , El Hajj Marcel M. , Johansen Kasper , McCabe Matthew F.
Published: February 2023

Mangroves are essential ecosystems composed of salt-tolerant plants that grow in tropical and subtropical intertidal zones, acting as a vital link between aquatic and terrestrial ecosystems. Interest in mangrove preservation and restoration has been increasing in recent years due to their important role in climate regulation by capturing and preserving carbon. Despite their importance, these ecosystems are under huge pressure due to human activities. It is estimated that these environments have lost up to half of the area occupied under pristine conditions. Leaf area index (LAI) is a well-known biophysical parameter related to plant health, as it provides information on the water, energy, and CO2 exchange between plants and the atmosphere. Unmanned aerial vehicles (UAVs) have emerged in recent years as a viable solution for ecosystem monitoring, as they allow for rapid and frequent data acquisition of a wide range of wavelengths. In this work, we evaluated the potential of multispectral images acquired by a UAV to estimate the LAI of a mangrove (Avicennia marina) forest located in the coastal area of the Red Sea in the Kingdom of Saudi Arabia. Multicollinearity assessment was performed to select significant variables suited for estimating LAI, including five multispectral bands, a canopy height model, and eight vegetation indices. Multicollinearity assessment was performed with three approaches: the Least Absolute Shrinkage and Selection Operator (LASSO), Random Forest (RF) for variable selection, and Hierarchical Cluster Analysis (HCA). The capability of significant variables to estimate LAI was assessed using the Generalized Linear Model (GLM), RF and Support Vector Machine (SVM). Results showed high estimation accuracy of LAI (R² = 0.91 for GLM, R² = 0.89 for RF and R² = 0.90 for SVM). However, further analysis showed that it is possible to estimate LAI of the mangrove forest with reasonable accuracy (R² = 0.87 for GLM, R² = 0.78 for RF and R² = 0.87 for SVM) using only two variables, the canopy height model and the GreenNDVI. The same variables were used to estimate LAI at another mangrove site and similar results were obtained (R² = 0.74 for GLM, R² = 0.73 for RF and R² = 0.68 for SVM). 
Emissions of SF6 in China inferred from atmospheric observations
Authors: An Minde , Prinn Ronald , Western Luke , Yao Bo , Hu Jianxin , Rigby Matthew
Published: February 2023

Sulfur hexafluoride (SF6) is the most potent non-CO2 Greenhouse Gas currently incorporated in the Paris Agreement, with a global warming potential of around 25,000 over a 100-year time horizon and lifetime of around 1,000 years. Global mole fractions and emissions of SF6 have increased substantially since the 2000s. The increasing SF6 emissions worldwide are thought to originate from its growing emissions in Kyoto Protocol non-Annex-I countries, where China is a major contributor. Top-down emission estimates provide evaluation of national bottom-up inventories, based on information from atmospheric observations. Previous top-down emissions of SF6 in China were determined by observations made outside of China (e.g., in Korea and Japan), which lack sensitivity to emissions in regions far from the measurement sites (like the western or southern parts of China). In this study, emissions of SF6 in China over 2011-2020 were derived using observations of SF6 from 9 sites within China, coupled with a Lagrangian transport model and a hierarchical Bayesian inference algorithm. Analysis of the sensitivity maps (footprints) of these measurement sites suggest broad sensitivity to the major emission areas in China. The emissions in China show a substantial increase throughout the study period and contribute substantially to the rise in global emissions. The spatial distribution of SF6 emissions in different regions or provinces in China and their changes are further analyzed. Finally, the potential industrial drivers behind the changes in emissions in China, and the necessity of continuous atmospheric observations in some key regions like in the northwest of China are discussed.
AMOC variations modulated by Tropical Indio-Atlantic SST Gradient
Authors: Ferster Brady , Borchert Leonard , Mignot Juliette , Fedorov Alexey
Published: February 2023

A potential future slowdown or acceleration of the Atlantic Meridional Overturning Circulation (AMOC) would have profound impacts on global and regional climate. Recent studies have shown that AMOC responds, among many other processes, to anthropogenic changes in tropical Indian ocean (TIO) temperature. However, internal unforced co-variations between these two basins are largely unexplored as of yet. Here, we use the ERSST v5, HadISST v1, and COBE v2 gridded observational products for the period 1870-2014, as well as dedicated simulations with coupled climate models, and show that internal changes in sea surface temperature gradients between the Indian and Atlantic Ocean (SSTgrad) can drive teleconnections that influence internal variations of North Atlantic climate and AMOC.We separate the unforced observed component (i.e., internal signal) from the forced signal following the residuals method presented by Smith et al. (2019). In the absence of direct AMOC observation we estimate AMOC variability from an SST index (SSTAMOC; Caesar et al., 2018). We find a robust observed relationship between the unforced tropical SSTgrad and SSTAMOC when TIO leads by ~25 years. This time-lag is in line with a recently described mechanism of anomalous tropical Atlantic rainfall patterns that originate from TIO warming and cause anomalously saline tropical Atlantic surface water which slowly propagate northward into the subpolar North Atlantic, ultimately altering oceanic deep convection and AMOC (Hu and Fedorov, 2019; Ferster et al. 2021). Our study now suggests that it is the tropical SSTgrad that drives those AMOC changes, with a limited role for the western tropical Pacific. Pre-industrial control simulations with the IPSL-CM6A-LR model confirm this relationship, indicating a time lag of ~25 years between SSTgrad and SSTAMOC variations. These simulations also confirm that the SSTAMOC is representative of unforced AMOC variations when SSTAMOC leads by 5 years. This work therefore indicates that an unforced pathway between tropical ocean temperature and AMOC exists with a ~20 year lag, which opens the potential for using SSTgrad as precursor to predict future AMOC changes. Caesar, L., Rahmstorf, S., Robinson, A., Feulner, G., & Saba, V. (2018). Observed fingerprint of a weakening Atlantic Ocean overturning circulation. Nature, 556(7700), 191-196.Ferster, B. S., Fedorov, A. V., Mignot, J., & Guilyardi, E. (2021). Sensitivity of the Atlantic meridional overturning circulation and climate to tropical Indian Ocean warming. Climate Dynamics, 1-19.Hu, S., & Fedorov, A. V. (2019). Indian Ocean warming can strengthen the Atlantic meridional overturning circulation. Nature climate change, 9(10), 747-751.Smith, D. M., Eade, R., Scaife, A. A., Caron, L. P., Danabasoglu, G., DelSole, T. M., ... & Yang, X. (2019). Robust skill of decadal climate predictions. Npj Climate and Atmospheric Science, 2(1), 1-10.
Black Carbon source apportionment using time-dependent Absorption Angstrom Exponent (AAE)
Authors: Savadkoohi Marjan , Pandolfi Marco , Alastuey Andrés , Querol Xavier , Favez Olivier
Published: February 2023

Among the aerosol particles optical properties, the Absorption Angstrom Exponent (AAE) is a crucial parameter describing the spectral dependence of light absorption by aerosols. It is intensively employed for black carbon (BC) source apportionment and aerosol characterization (e.g., BC, Brown Carbon “BrC,” and dust). AAE has been widely investigated using data from filter-based absorption photometers such as the AE33 that measure light absorption at seven wavelengths (370-950 nm). BC source contribution is commonly obtained by applying the most frequent source apportionment method, the Aethalometer model. This model requires a-priori knowledge of the AAE of the fossil and non-fossil (e.g. biomass burning) BC sources and values of around 1 (AAEff; fossil) and 2 (AAEwb; non-fossil) are commonly used. In this work, in order to improve the results of the aethalometer model for BC source apportionment, we investigate the model performances resulting from using site-dependent AAEff and AAEwb determined from the experimental data. These latter were obtained by studying the frequency distributions of experimental AAE calculated from AE33 data collected at urban sites in the frame of the RI-URBANS project. However, AAE can also vary with time depending on changing burning fuels and burning conditions, and single constant AAEff and AAEwb values cannot be representative of the whole measurement period considered. For this reason, we also evaluated the use in the Aethalometer model of experimental time-dependent rolling AAEff and AAEwb. This improved AAE-frequency-distribution-based Aethalometer model could be applied in near-real time to obtain the BC source apportionment. Thus, it could help to improve our understanding of AAE values considering uncertainties to provide a better and more accurate quantity to differentiate between BC sources.
Numerical investigation on the impact of thermo-osmosis on fluid pressurisation and barrier integrity in Boom clay – a case study of the ATLAS in-situ full-scale heating experiment.
Authors: Kiszkurno Feliks , Buchwald Jörg , Kolditz Olaf , Nagel Thomas
Published: February 2023

Existing literature suggests the importance of the thermo-osmosis (TO) for an accurate simulation of pore pressure evolution in heater tests for nuclear waste disposal in clay rock. However, there is limited consensus regarding the appropriate choice of parameters controlling TO and the extent of its physical impact. Uncertainty of parameters describing the host rock and their spatial variability further add to  both the complexity of this consideration. This study will use the ATLAS in-situ full-scale heating experiment from the HADES underground research laboratory in Mol, Belgium, to investigate the impact of TO on the thermal pressurisation in Boom Clay and its significance for the evaluation of barrier integrity.The ATLAS experiment was simulated with an inelastic thermo-hydro-mechanical model implemented in OpenGeoSys. After comparison to published data, assisted-history-matching was performed to obtain a good representation of the in-situ measurements with and without taking into account TO. The comparison of both groups allows a clearer discussion of the influence of TO on temperature and pressure evolution in the studied system. The final step -- uncertainty quantification of the TO parameterisation -- puts the results in the context of the large parameter uncertainty documented in the literature. Subsequently, the impact of TO and said uncertainties on barrier integrity was estimated in terms of area and duration of potential integrity violation using statistical and geometrical methods.  
Evaluating the global wastewater’s untapped irrigation potential
Authors: Fridman Dor , Kahil Taher , Wada Yoshihide
Published: February 2023

Wastewater has been increasingly considered an untapped resource rather than a waste. It can be used for water supply, aquifer recharge, energy generation, and fertilizer production, contributing concurrently to achieving multiple Sustainable Development Goals. Currently, treated wastewater is used for irrigation in different water-scarce countries like Israel and Spain. Recent estimates suggest that treated wastewater irrigates 6 million hectares (Mha) of cropland worldwide, with global potential for irrigating 31-42 Mha. Nevertheless, these estimates often do not account for environmental, social, and economic conditions that may limit this potential, including irrigated crops’ spatial distribution, water quality requirements, and water conveyance options.Our study advanced a spatial-explicit analysis of four different technological scenarios and estimated the untapped potential of wastewater irrigation at a global, regional, and national scale. We found that utilizing treated wastewater for irrigation can satisfy up to 4% of the global irrigation demand. Considering only water-scarce regions, reduce this global potential to roughly 2%. However, intensification and expansion strategies or scenarios can increase this irrigation share. For example, in ten countries, delivering treated wastewater to croplands by canals adds over 5% to the share of treated wastewater relative to total irrigation demand. An increase of over 1% is evident in 30 countries, mainly in the Middle East, North Africa, and Western Europe.Increased wastewater treatment capacity (i.e., expansion strategy) potentially increases the share of global irrigation demand satisfied with treated wastewater to 6% -12%. Some regions’ potential exceeds 20% of their irrigation demand, e.g., China and North America. An increase in potential wastewater irrigation becomes significant when considering expansion scenarios (e.g., increased capacities to treat the wastewater).Considering the changes in different regions’ water scarcity, we find that the potential share of irrigation demand satisfied by treated wastewater is significantly increased in North America, the United Kingdom, Europe, and Western Asia. We conclude that irrigation with treated wastewater in these regions can be an important climate change adaptation measure. Besides, we show that intensifying and expanding wastewater reclamation systems can help manage droughts in regions with high drought risk, like the Italian Po and French Loire River basins.By exploring expansion and intensification strategies to reclaim treated wastewater, this work establishes an essential step towards planning the global and regional pathways to utilize this untapped resource, abating current and future water scarcity risks.
Uncertainties in Greenland ice sheet evolution and related sea-level projections until 2
Authors: Rahlves Charlotte , Goelzer Heiko , Langebroek Petra , Born Andreas
Published: February 2023

The Greenland ice sheet is currently one of the main contributors to sea-level rise and mass loss from the ice sheet is expected to continue under increasing Arctic warming. Since sea-level rise is threatening coastal communities worldwide, reducing uncertainties in projections of future sea-level contribution from the Greenland ice sheet is of high importance. In this study we address the response of the ice sheet to future climate change. We determine rates of sea-level contribution that can be expected from the ice sheet until 2100 by performing an ensemble of standalone ice sheet simulations with the Community Ice Sheet Model (CISM). The ice sheet is initialized to resemble the presently observed geometry by inverting for basal friction. We examine a range of uncertainties, associated to stand alone ice sheet modeling by prescribing forcing from various global circulations models (GCMs) for different future forcing scenarios (shared socioeconomic pathways, SSPs). Atmospheric forcing is downscaled with the regional climate model MAR. The response of marine terminating outlet glaciers to ocean forcing is represented by a retreat parameterization and sampled by considering different sensitivities. Furthermore, we investigate how the initialization of the ice sheet with forcing from different global circulation models affects the projected rates of sea-level contribution. In addition, sensitivity of the results to the grid spacing of the ice sheet model is assessed. The observed historical mass loss is generally well reproduced by the ensemble. The projections yield a sea-level contribution in the range of 70 to 230 mm under the SSP5-8.5 scenario until 2100. Climate forcing constitutes the largest source of uncertainty for projected sea-level contribution, while differences due to the initial state of the ice sheet and grid resolution are minor.  
Recoverable cushion gas in hydrogen storage as a national gas reserve for energy security
Authors: Heinemann Niklas
Published: February 2023

Large-scale storage of energy is an effective and efficient way to increase energy security. Europe is highly dependent on gas imports, but gas storage capacity has not been expanded accordingly. An increased deployment of renewable energy sources such as wind and solar will require additional energy storage to balance intermittencies, for example in the form of subsurface hydrogen storage. Hence the development of more geological storage sites is inevitable, and detailed asset planning needs to commence today.

Cushion gas is an expensive but necessary investment in gas storage, especially in subsurface hydrogen storage as hydrogen will remain a commodity in high demand. A reduction of the cushion gas in hydrogen storage – either replacing H2 cushion gas with alternative gases or reducing the cushion gas to working gas ratio – will introduce uncertainties in terms of hydrogen purity and injection and reproduction rates, and the cost-reducing effect might backfire.

However, a certain part of the cushion gas can also be regarded as an asset, as it can be reproduced efficiently by standard production techniques. This “recoverable cushion gas” could act as a national gas reserve for times of severe energy shortages. The state could dictate to access this one-time energy backup during times of energy emergency, and therefore this particular share of the cushion gas should be paid for by the government, combining economic gas storage with national emergency gas reserves for an increase in national energy security. For this study, a North Sea gas store was used to illustrate and quantify the idea.

As part of the cushion gas would be an investment into energy security by the government, the use of “recoverable cushion gas” could reduce implementation costs for hydrogen storage sites and set the incentive to massively expand low-carbon energy storage.  
Multiscale properties of the ionospheric electric field in the auroral region from a one-year survey with CSES-01.
Authors: Papini Emanuele , Piersanti Mirko , Diego Piero , Consolini Giuseppe , D'Angelo Giulia , Recchiuti Dario , Zhima Zeren
Published: February 2023

We present the results of a study of the electric field properties in the auroral oval (AO) region. We exploit more than one year of electric field measurements taken by the EFD instrument onboard the China-Seismo-Electromagnetic Satellite 01 (CSES-01) spacecraft, orbiting sun-synchronously at around 500 km of altitude inside the Earth ionosphere. To exploit the high temporal resolution of EFD, we devise a new technique that allows to detect the crossing of the AO by CSES-01 using electric field measurements only. This new technique combines a median-weighted local variance measure and Iterative Filtering to automatically isolate high levels of electromagnetic activity caused by, e.g., particle precipitation and Field Aligned Currents (FAC) at auroral latitudes. We validate this new method on few selected orbits against other standard proxies, such as the SWARM single-FAC product and the auroral radiance emission measured by SSUSI onboard the DMSP constellation. Furthermore, we identify ~3 000 orbits (on a dataset of ~10 000) of high geomagnetic activity where CSES either crossed the AO boundary or the polar cap region and characterize the multiscale (down to characteristic electron scales) statistical properties of the electric field. This work represents the first systematic study of the Auroral electric field, with many potential applications to space-weather studies, thanks to the large amount of continuous observations of the ionosphere carried out by CSES-01. 
First archive of extensive N-fixation by volcanic lightning and implications for the prebiotic Earth
Authors: Aroskay Adeline , Martin Erwan , Bekki Slimane , Savarino Joël , Le Pennec Jean-Luc , Temel Abidin , Manrique Nelida , Aguilar Rigoberto , Rivera Marco , Szopa Sophie
Published: February 2023

On Earth, most of the nitrogen (N) accessible for life is trapped in dinitrogen (N2), which is the most stable atmospheric molecule. In order to be metabolised by living organisms, N2 has to be converted into assimilable forms, also called fixed N. Nowadays, nearly all the N-fixation is achieved through biological and anthropogenic processes. However, in early environments of the Earth, before the emergence of life, N-fixation must have occurred via natural abiotic processes. Electrical discharges, including from thunderstorms and also lightning associated with volcanic eruptions is one of the most invoked processes. The occurence of volcanic lightning during explosive eruptions is frequent, and convincing laboratory experimentations support the role of this phenomenon, however no evidence of substantial N-fixation has been found in volcanic records. Here we report on the discovery of large amounts of nitrates in volcanic deposits from Neogene caldera-forming eruptions, which are well correlated with the concentrations of species directly emitted by volcanoes such as sulphur and chlorine. The multi-isotopic composition (δ18O, Δ17O) of the nitrates reveals that they originate from the atmospheric oxidation of nitrogen oxides formed by volcanic lightning that occur during the eruption. According to these volcanic nitrate records, our first estimates suggest that about 60 Tg of N can be fixed during a large explosive event. Our findings hint at a unique role potentially played by subaerial explosive eruptions in supplying essential ingredients for the emergence of life on Earth.
Evolution of the oxygen escape from Earth over geological time scales
Authors: Alonso Tagle Maria Luisa , Maggiolo Romain , Gunell Herbert , De Keyser Johan , Cessateur Gael , Lapenta Giovanni , Pierrard Viviane , Vandaele Ann Carine
Published: February 2023

Atmospheric erosion plays a significant role in the long-term evolution of planetary atmospheres, and therefore on the development and sustainability of habitable conditions. Atmospheric escape varies over time, due to changes in planetary conditions and the evolution of the Sun. In the case of a magnetized planet like Earth, the dominant scavenging mechanisms are polar wind and polar cusp escape. Both processes are sensitive to the ion supply from the atmosphere, which depends on the solar EUV radiation and the composition of the neutral atmosphere. Moreover, they are modulated by the coupling between the solar wind and the ionosphere, which depends on the solar wind dynamic pressure and the planetary magnetic moment.We developed a semi-empirical model of atmospheric loss to extrapolate from current measurements of oxygen escape from Earth to past conditions. This model takes into account the variations of the solar EUV/UV flux, the solar wind dynamic pressure, and the Earth’s magnetic moment. In this study, we identify the main factors and processes that control oxygen escape from Earth, considering present-day atmospheric conditions. We constrain the variation of the oxygen loss rate over time and estimate the total oxygen loss during the last ~2 billion years.