bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-variate data assimilation into a large scale hydrological system: a study over the Niger basin
Authors: Pedinotti Vanessa , Larnicol Gilles , Pena Luque Santiago , Zawadzki Lionel , Tanimoun Bachir , Soungalo Kone
Published: February 2023

The advent of new satellite missions dedicated to hydrology, such as SWOT launched in December 2022, brings fresh perspectives for monitoring and forecasting continental water resources. But it also requires the set up of fully automated hydrological forecasting systems able to take advantage of these new types of products. It is in this perspective that a platform named HYdrological Forecasting system with Altimetry Assimilation (HYFAA) was implemented, which encompasses the MGB large-scale hydrological model developed within the large-scale hydrology research group of the University of Rio Grande do Sul (Brazil), and an Ensemble Kalman Filter (EnKF) module that corrects model states and parameters whenever discharge observations are available. While discharge is the most classically used variable for data assimilation into hydrological models, it does however have some limitations: i) it only provides 1D information about the hydrological flow and cannot capture lateral processes which are essential in flooded areas; ii) it must be derived from nadir altimetry data, which has limitations in terms of spatial sampling, via rating curves. Combining discharge observations with other types of data can therefore improve models' representation of the complex processes governing the hydrological regime of large basins. The current work is part of a CNES-funded project aiming to implement and evaluate multivariate data assimilation on the Niger river basin based on the HYFAA modeling platform. Three types of observations will be assimilated: water levels and discharge from the Hydroweb database, and surface water bodies from Sentinel-1 and Sentinel-2 data processing. This study presents the preliminary results obtained within the framework of this project. First, we evaluate and compare the performance of the EnKF when assimilating each variable separately. For validation, we use in-situ or independent datasets when they exist. Otherwise, we use a random sample of the assimilated datasets. We then discuss the approach to be taken and the risks to be anticipated for their combined assimilation. This study allows preparing the use of SWOT data as soon as they are available in the course 2023.
Seasonal variability of atomic hydrogen and oxygen in the EMM/EMUS cross-exospheric observations during Mars year 3
Authors: Raghuram Susarla , Chirakkil Krishnaprasad , Deighan Justin , Chaffin Michael , Jain Sonal , Lillis Robert , Gacesa Marko , Fillingim Matthew O. , Brain David , Thiemann Ed , Eparvier Frank , Holsclaw Greg , England Scott , Evans Scott , Lootah Fatma Hussain , Al Mazmi Hoor Abdelrahman , Curry Shannon , Al Matroushi Hessa Rashid
Published: February 2023

Atomic hydrogen and oxygen are the dominant species in the Martian exosphere. Atomic hydrogen is essentially produced from the dissociation of H2O, whereas, hot oxygen atoms are populated by non-thermal processes such as the dissociative recombination of O2+ with electrons in the Martian ionosphere. The study of these species helps to understand the evolution of the Martian atmosphere and more specifically the history of water on Mars.  The Emirates Mars Ultraviolet Spectrometer (EMUS), one of the primary instruments onboard the Emirates Mars Mission (EMM), has been observing atomic hydrogen and oxygen in the Martian exosphere over the Mars Year 36. We present the analysis of the cross-exospheric observations by the EMUS for hydrogen Lyman series and oxygen 130.4 nm emissions and their seasonal variability. The EMUS cross-exospheric observations cover the tangent altitude starting from 130 km to more than 35,000 km above the disk (see Fig. 1), with most of the observations below 25,000 km. The observations show that when Mars moved from perihelion to aphelion, the hydrogen emission line intensities increase by an order of magnitude or more whereas, for oxygen, it is an increment by a factor of about 2 at larger altitudes. Based on these observations, we also discuss the retrieval of densities, temperature, and the estimation of escape fluxes of hydrogen and oxygen species by applying 3D hydrogen ballistic corona and 3D Monte Carlo particle transport models, respectively.Figure 1: The EMM-observed cross-exosphere emission intensity profiles of atomic hydrogen and oxygen during Mars Year 3
Multi-hazard analysis of abandoned coal-mines
Authors: Marwan AL Heib
Published: February 2023

Nowadays, most of the coal mines in Europe are already closed or are in a state of liquidation. However, the problem of abandoned coal mines and their influence on the environment remains central for the mining industry and coal regions in transition. After the end of the exploitation, many disturbances can occur. Mines operators, local authorities and decision makers are confronted with multi-hazard and risks related to mine closure. Land use planning and adequate site rehabilitation requires better tools to deal with the multiple hazards and constraints.The objective of the study is to improve risk assessment by establishing a new methodology to assess the interaction between hazards related to old mines, and no longer treat them separately.Mining hazards concern: ground movements, hydrological hazards, self-heating, soil and water pollution. One hazard can trigger another one. Different tools are presented such as a global matrix, a fault tree, etc. for identifying the hazards interaction. The hazard interaction matrix has been constructed, figure 1 shows in particular the interactions that the phenomena in the columns (source phenomenon) can have with the phenomena in the rows (target phenomenon). The matrix also provides information on the levels of interaction: no known case of interaction between phenomena (white colour), Low (yellow), Medium (green) and High (red). These assessments are based on feedback and in-depth discussion between experts. This approach is a first tool to help mining and development actors to understand these interactions and improve mitigation and management measures. 
Taxonomy of Cliff Failure Criteria: Phase Field Modelling and Parallels with Other Models
Authors: Stocek Jakub , Arthern Robert , Marsh Oliver
Published: February 2023

Ice loss from glaciers and ice sheets is the largest contributor to sea level rise. Damaged ice is central to the stability of the Antarctic Ice Sheet and calving of tabular icebergs from ice shelves accounts for more than half of all the ice lost from Antarctica each year. The processes driving calving and fracture are complex but not yet well understood. The aim of this talk is to present a physically based modelling of fracture. The timing of calving is currently difficult to predict and is only included in some ice sheet models. Calving and cliff retreat rates are based on heuristic arguments or limited observations scaled up to the whole of Antarctica. There is no guarantee that current methods accurately capture the sea level contributions and physically based modelling is needed. Recently, phase field models for fracture have gained a large following due to their ability to predict complex cracking phenomena such as crack branching and coalescence, or crack nucleation and have been applied to ice sheets for example by Clayton et al. (2022). We employ a phase field formulation of fracture for Maxwell viscoelastic materials capable of capturing the creep of glacial ice over longer periods as well as instantaneous elastic deformation. In this talk we present different failure criteria and fracture driving forces used in phase field modelling and their impact on cliff retreat rates. We draw parallels with existing models and commonly used failure criteria and expand on the possibilities of using phase field modelling in large scale domains. Clayton, T., Duddu, R., Siegert, M., Martínez-Pañeda, E. (2022). A stress-based poro-damage phase field model for hydrofracturing of creeping glaciers and ice shelves. Engineering Fracture Mechanics, 272, 108693.
Ambient H/V sensitivity to the dynamics of glaciers and ice sheets
Authors: van Ginkel Janneke , Walter Fabian , Nap Ana , Häusler Mauro , Lüthi Martin
Published: February 2023

Climate change is causing major shifts in the dynamics of the cryosphere, leading to sea-level rise, glacier break-off events, flooding, and landslides. Geological, thermodynamic and hydraulic processes at the base of an ice mass play a central role in ice flow dynamics, and understanding these is imperative for predicting ice body behavior in a changing climate. To this end, sustained ambient vibrations in glaciated environments can be used to monitor subglacial conditions over significant spatial extent with relatively low-cost acquisition.In earthquake seismology, a well-established methodology to investigate subsurface properties is the horizontal-to-vertical spectral ratio (H/V) of ambient seismic ground unrest. In cryoseismology, the H/V approach is already used to invert for velocity profiles of ice or firn, to obtain bedrock topography and to identify the presence of basal sediments. To date, only a few hours of seismic vibration records are typically used. Yet in such short time records, biases may arise because of the dynamic character of the glacier. Seismic resonances within the soft ice layer and resulting H/V ratios are expected to vary with changes in subglacial hydraulic conditions.We propose to leverage temporal variations in H/V spectra to investigate subglacial processes. As a case study, we first focus on the Glacier de la Plaine Morte (Switzerland), where a seismic array was deployed for four months in summer of 2016. During this time, an ice-marginal lake formed and suddenly drained through and under the glacier, making this seismic record ideal for our purposes. This drainage event is well recorded and strongly influences the H/V in terms of amplitude and resonance frequency. We next present ambient H/V measurements of the Sermeq Kujalleq in Kangia (also known as Jakobshavn Isbræ), one of Greenland’s largest outlet glaciers. Here, the H/V spectra show multiple resonances over time, whose origin we discuss in more detail. For both our study cases, separating variations in source and medium properties is pivotal. Tackling this challenge provides glaciologists with a valuable tool to investigate the poorly accessible subglacial environment, which holds the key to our understanding of ice flow and eustatic sea level rise.
Mutual interactions between waves and turbulence: an experiment
Authors: Ellingsen Simen Å , Smeltzer Benjamin K , Rømcke Olav , Hearst R Jason
Published: February 2023

 The mutual interaction between waves and turbulent currents plays a key role in the energy budget, mixing and mass transfer in the upper layer of the ocean. Turbulence is ubiquitous in the uppermost layer of the ocean, where it interacts with surface waves. Theoretical, numerical, and experimental works (e.g. [1 - 3] and others) predict that motion of non-breaking waves will increase turbulent energy, in turn leading to a dissipation of waves and, potentially, increased mixing and gas transfer between ocean and atmosphere. Conversely, waves encountering a turbulent currents will be scattered and directional seas can suffer a broadening of the directional spectrum [4,5].In this work we study how the mutual interaction of waves and turbulent flow depends on the properties of the ambient turbulence. The measurements were performed in the water channel laboratory at NTNU Trondheim [6], able to mimic the water-side flow in the ocean surface layer under a range of conditions. An active grid at the inlet allowed the turbulence intensity and length scale to be varied for the same mean flow. The flow field was measured in the spanwise-vertical plane by stereo particle image velocimetry for various background turbulence cases with waves propagating against the current. Scattering was measured with pairs of wave probes at increasing distances from the wave-maker.A strong increase in streamwise enstrophy (mean-square streamwise vorticity) is observed after vs before the passage of a long, Gaussian wave group. Enstrophy is intensified under troughs and reduced under crests. Scattering is observed, increasing linearly with propagation distance. The scattering rate is found to depend primarily on the energy content at the largest turbulent scales larger than a wavelength, whereas the intensification of turbulence by waves occur at length scales smaller than a wavelength.[1] Teixeira M. and Belcher S. 2002 “On the distortion of turbulence by a progressive surface wave” J. Fluid Mechanics 458 229-267.[2] McWilliams J. C., Sullivan P. P. and Moeng C-H. 1997 “Langmuir turbulence in the ocean” J. Fluid Mechanics 334 1-30.[3] Thais L. and Magnaudet J. 1996 “Turbulent structure beneath surface gravity waves sheared by the wind” J. Fluid Mechanics 328 313-344.[4] Phillips O. M. 1959 "The scattering of gravity waves by turbulence"  J. Fluid Mech. 5 177-194.[5] Fabrikant and Raevsky 1994 "The influence of drift flow turbulence on surface gravity wave propagation" J. Fluid Mech. 262 141-156.[6] Jooss Y., Li L., Bracchi T. and Hearst R.J. 2021 “Spatial development of a turbulent boundary layer subjected to freestream turbulence” Journal of Fluid Mechanics 911 A4.
Burned soils in Europe require attention: post fire soil erosion is long lasting
Authors: Vieira Diana , Borrelli Pasquale , Jahanianfard Dina , Benali Akli , Scarpa Simone , Panagos Panos
Published: February 2023

Annually, millions of hectares of land are affected by wildfires worldwide, disrupting ecosystems functioning by affecting on-site vegetation, soil, and above- and belowground biodiversity, but also triggering erosive off-site impacts such as water-bodies contamination or mudflows. Wildfires consist in an environmental problem with a global dimension, and its occurrence at EU scale is well documented.However, the estimation of the indirect impacts of wildfires, such as increased soil erosion at wider scales, are still lacking. In this study, we present a soil erosion assessment following the 2017's wildfires at the European scale with the RUSLE model, including an analysis of vegetation recovery and soil erosion mitigation potential (Vieira et al., 2023).Results indicate a sharp increase in soil losses with 19.4 million Mg additional erosion in the first year following the wildfire when compared to unburned conditions. Over five years, 44 million Mg additional soil losses were estimated, and 46% of the burned area presented no signs of full recovery. Post-fire mitigation with mulching could attenuate these impacts by 63–77%, reducing soil erosion to background levels by the 4th post-fire year. Soil erosion risk based mitigation strategies revealed near optimal mitigation potential when compared with thoses based on burn severity alone.Our insights may help identifying target policies to reduce land degradation, as identified in the European Union Soil, Forest, and Biodiversity strategies. Vieira, D.C.S., Borrelli, P., Jahanianfard, D., Benali, A., Scarpa, S., Panagos, P., 2023. Wildfires in Europe: Burned soils require attention. Environmental Research, 2023, 217, 114936. https://doi.org/10.1016/j.envres.2022.114936 
Estimating the effect of roadside barriers in reducing PMs concentration with PALM - 4U
Authors: Brondani Daiane , Giostra Umberto , Mortarini Luca
Published: February 2023

Air pollution from traffic is one of the leading causes of disease and premature death, potentially affecting all human body organs, depending on exposure to polluting sources. Among the main harmful agents to human health are fine particulate materials (PMs), such as PM 10 μm, PM 2.5 μm, and PM 1 μm. The finest particulates, like PM 2.5 μm and PM 1 μm, are easily inhaled, causing respiratory problems such as irritation in the airways, coughing or difficulty breathing, worsening asthma, developing chronic bronchitis, irregular heartbeat, non-fatal heart attacks, premature death in people with heart disease, decreased lung function, contributing to the developing lung cancer. In addition, transported by the wind and then deposited in soil or water, the fine particulate contributes to the alteration of their acidity and nutrients, causing damage to forests and agricultural plantations. The present study investigates the ability of non-porous (concrete, glass) and porous (vegetation) barriers to attenuate the dispersion of fine particulate from roadway traffic. Large Eddy Simulations combined with observational data are used to evaluate the effectiveness of the different barriers in reducing the particulate concentration downwind from the roadway. Different types of barriers, different distances between the road and the barrier, and different barrier heights are simulated with PALM - 4U. The simulated concentration fields are compared to the Marche Region (Italy) measurements.
European Extreme Events Climate Index (E3CI)
Authors: Giugliano Giuseppe , Rianna Guido , Pugliese Alessandro , Barbato Giuliana , Ellena Marta , Mercogliano Paola , Tirri Antonio , LoConti Francesco
Published: February 2023

The European Extreme Events Climate Index (E3CI) is an innovative climate service (operational since January 2021) to assess the frequency and severity of weather-induced hazards over Europe. This service has been funded by Foundation Big Data and Artificial Intelligence for Human Development (IFAB) and developed through the collaboration between Fondazione CMCC Euro-Mediterranean Center on Climate Change (CMCC) and Leithà Unipol Group. Specifically, E3CI proposes to define a synthetic index aimed at providing information about the areas affected by different types of weather-induced hazards and the significance of such events. At this stage, E3CI permits equipping Europe, SADC (Southern African Development Community) and North America with an index similar to Actuaries Climate Index, (NA-ACI; actuariesclimateindex.org) developed over North America and already fully operational. From a methodological point of view, using ERA5 reanalysis data (Hersbach et al., 2020), E3CI permits evaluating seven main dynamics: cold and heat stresses, droughts, extreme precipitation, winds, the predisposing conditions leading to hail events and forest fire. Furthermore, five E3CI components are tested using a subset of regional climate projections from the EURO-CORDEX (Jacob et al., 2014, 2020; Giorgi and Gutowski, 2015) program at the highest available resolution (about 11 km) considering three different future periods (2011-2040; 2041-2070; 2017-2100) and three different concentration scenarios. The data are aggregated at different Administrative unit levels and combined into a single index providing an overall view for the domain and period of interest. A key aspect of E3CI is the standardization of the different components over a reference thirty-year period (1981-2010). It is a key aspect of the process because it makes comparable the outputs returned according to different approaches and for different issues; it can limit, in a way, also the influence of potential weaknesses affecting the original datasets used for computation. E3CI applications range in a wide area comprising both scientific and technical use cases. Such information can be useful to adjust rate adequacy levels, improve budgeting capabilities and risk management, designing index-linked financial instruments and new insurance and reinsurance products. In addition, E3CI can be adopted to pursue education and sustainability targets, such as to increase awareness about climate change impacts, to support public decision-making processes for sustainable development, to provide a scientifically-sounding measure to monitor climate trends. Finally, this service can change the way financial and insurance markets operate by providing indices that allow to more accurately measure risks related to extreme weather conditions.
Three-decades of quality controlled Greenland Climate Network (GC-Net) weather station data
Authors: Box Jason , Vandecrux Baptiste , Ahlstrøm Andreas , Fausto Robert , Colgan William , Karlsson Nanna , Andersen Signe , Wright Patrick , Houtz Derek , McGrath Daniel , Cullen Nicolas , Bayou Nicolas , Steffen Konrad
Published: February 2023

The Greenland Climate Network (GC-Net) is a collection of automatic weather stations (AWS)  across the Greenland Ice Sheet. The first site was initiated in 1990, and the project has operated almost continuously since 1995, under the leadership of the late Pr. Konrad Steffen. The network consists of 19 long-running weather stations, and 14 AWS sites active under five years. As part of the continuation of the GC-Net by the Geological Survey of Denmark and Greenland (GEUS), the AWS data have recently undergone a reprocessing with new attention to erroneous data filtering, correction and derivation of additional variables: continuous surface height, instrument heights, turbulent heat fluxes.  This new augmented GC-Net level 1 (L1) AWS dataset is now available at https://doi.org/10.22008/FK2/VVXGUT and will continue to be refined. The processing scripts, the latest data and a data-user forum are available at https://github.com/GEUS-Glaciology-and-Climate/GC-Net-level-1-data-processing. In addition to the AWS data, a comprehensive compilation of valuable metadata is provided: maintenance reports, yearly pictures of the stations and the moving station positions through time. This unique dataset provides more than 320 station-years of weather data of improved quality and is made available in compliance under FAIR open data and code principles.
Large effects of ocean circulation change on Greenland ice sheet mass loss
Authors: Vizcaino Miren , Rudlang Julia , Muntjewerf Laura , Georgiou Sotiria , Sellevold Raymond , Petrini Michele
Published: February 2023

The Greenland ice sheet (GrIS) is currently losing mass at an accelerated rate, due to atmospheric and ocean warming causing respectively enhanced melt and ice discharge to the ocean. A large part of the uncertainty on future GrIS contribution to sea level rise relates to unknown atmospheric and ocean circulation change. For the later, AR6 models project a weakening of the North Atlantic Meridional Overturning Circulation (NAMOC) during the 21st century. The magnitude of this weakening depends on the greenhouse gas scenario and model, but none of the models project a complete collapse.Projections of future GrIS evolution in the last IPCC report AR6 are mostly based on simulations with ice sheet models forced with the output of climate models (e.g., Goelzer et al. (2020)). This method permits large ensembles of simulations, however the coupling between climate and GrIS is not represented. Here, we use a coupled Earth System and Ice Sheet Model (ESM-ISM), the CESM2-CISM2 (Muntjewerf et al. 2021) to examine the multi-millennial evolution of the GrIS surface mass balance for a middle-of-the-road CO2 scenario. The model couples realistic simulation of global climate (Danabasoglu et al. 2020), surface processes (van Kampenhout et al. 2020) and ice dynamics (Lipscomb et al. 2019). We use an idealized scenario of 1% CO2 increase until stabilization at two times pre-industrial values.  compare our results with pre-industrial and 1% to 4xCO2 simulations (Muntjewerf et al. 2020).We find small increases and even reduction of annual temperatures in the GrIS area in connection with strong NAMOC weakening in the first two centuries of simulation. Summer temperatures and surface melt increase moderately with respect to pre-industrial. From simulation year 500, the NAMOC recovers, resulting in strong increases in GrIS melt rates and contribution to sea level rise. We compare the deglaciation pattern over a period of 3,000 years with deglaciation simulations with the same model for the last interglacial (Sommers et al. 2021). 
Relative earthquake location of low-energy volcanic seismicity at Campi Flegrei
Authors: Danesi Stefania , Pino Nicola Alessandro , Carlino Stefano , Kilburn Christopher
Published: February 2023

This work intends to contribute to the comprehension of the Campi Flegrei caldera (CFc) unrest, through the relative relocation of the diffuse seismicity recorded during the 1982-84 unrest and after its reactivation in 2005.The CFc is one of the best monitored volcanic areas in the world, with a multi-parametric network of observing stations operating in the area. The shallow structure of the caldera, between 1 and 3 km, is a high-temperature hydrothermal system formed by a sequence of volcanoclastic, tuffs, lava, and marine deposits. The temperature gradient measured in deep boreholes, down to a depth of about 3 km, exceeds 150°C/km. A zone of pressurized gas and sill intrusion is possibly located at 3-4 km. A long-term magma reservoir is hypothesized in the deep structure (7-9 km), persistently supplying CO2 to the surface (observable for the continuity of gas emission to the fumaroles of Solfatara-Pisciarelli as well).While the unrest of 1982-84 has been generally associated with magma injection, a mechanism of fluid pressurization and heating of the CFc hydrothermal system is thought to be the primary forcing of ground deformation and shallow seismicity of the ongoing unrest. However, the mechanisms that control the interaction between the rising of fluids from deeper volumes and the seismicity within and below the hydrothermal system are still debated.In this work we use the arrival times of located seismic events to perform a double-difference relative relocation of earthquakes that occurred in the years 1982-84 and 2005-2022. Moreover, by using calibration laws for magnitude scales to infer the moment magnitude Mw from available catalogs of duration magnitude Md, we estimate the spatial distribution of the cumulative seismic energy released during the two considered time spans.The final distributions of hypocenters and radiated seismic energy, and their spatio-temporal evolution, suggest constraints for the identification of preferential pathways of rising fluids and for the imaging of structural barriers. These results can be interpreted jointly in light of previous works and available tomographic models for the definition of possible scenarios of unrest evolution.
The failure pattern and transfer features of the 2020 Qingliucun landslide
Authors: li longqi
Published: February 2023

The 2020 December 5th Qingliucun landslide in western China presents a high locality and complex movement features. Its landslide source sits at the margin of a platform of a hillslope, which suffers from repeated earthquake and snow-water infiltration. The data from Insar and monitoring devices reveal that this landslide body have deform for 6 years and present a stepped three-phase failure process. The PFC simulation is also used to reproduce the failure process and motion features. It is found that several earthquakes result in the initiation of this landslide body and the snow-water infiltration plays a direct role in triggering this landslide by weakening the strength of soils. The landslide body scrape the slope mass during its transfer and block the river near the toe of the hillslope. The huge energy of landslide body is consumed during this process as verified by PFC simulation. The results can offer a good guidance to the hazard mitigation of this kind of landslide.
Drivers of Topography in Fold-thrust Belts: A Perspective from Central Nepal
Authors: Eizenhöfer Paul R. , McQuarrie Nadine , Ghoshal Suryodoy , Mutz Sebastian G. , Ehlers Todd A.
Published: February 2023

Topography in compressional mountain ranges represents an interface at which tectonic and climatic forces interact. Understanding the relative contribution of these two components to mountain formation has been at the forefront of research over the last two decades. The theory underlying the mechanics that govern these interactions has been built on Coulomb wedge mechanics, i.e., mechanical failure and rock uplift occur everywhere along the wedge and the orogen. Observed rock displacement along single, discrete fault planes, including the translation of uplifted topography laterally, appears to be counter to such mechanics. However, a critically tapered topography across fold-thrust belts still emerges. If a critically tapered topography along an orogenic wedge can be produced by the sequential evolution of the subsurface fault geometry and the associated motion of bedrock over discrete fault planes, then a mechanical failure everywhere is not required. Here, the geomorphic evolution of the fold-thrust belt in central Nepal since the Miocene is investigated using a numerical surface processes model whereby the structural geometry, location and magnitude of fault motion are prescribed and based on observations. In addition, end-member climatic scenarios are adopted, i.e., uniform precipitation and climatic change over geologic time as predicted by atmospheric general circulation models. The experiments reproduce the first-order topography of central Nepal. Our modelling results indicate a dynamic variability of erosional efficacy that promotes the interplay of two modes of orogenic wedge behaviour and are contrary to a mechanical failure everywhere along the wedge: (mode 1) phases of lateral translation of uplifted topography and in-sequence propagation of deformation fronts, and (mode 2) phases of hinterland incision during out-of-sequence fault activity. The successful replication of first-order geomorphic indices in central Nepal in our experiments confirms an unusually long-lasting Miocene to Pliocene activity of the Main Boundary Thrust in central Nepal. This period is followed by Late Pleistocene hinterland incision coeval with out-of-sequence fault activity prior to the onset of rock displacement along the Main Frontal Thrust during a time of increased precipitation relative to today.               
Catching the time-variable gravity at Mt. Somma-Vesuvius volcano (Southern Italy) by means of discrete and continuous relative gravity measurements
Authors: Riccardi Umberto , Carlino Stefano , Pivetta Tommaso , Hinderer Jacques , Rosat Severine
Published: February 2023

We report the results of about 20 years of relative gravity measurements acquired on Mt. Somma-Vesuvius INGV monitoring network, together with about 9 months of continuous gravimetric recordings collected with the new generation relative gravimeter gPhoneX#116, specifically designed for continuous gravity recording. We also present the outcomes of an intercomparison experiment of the gPhone#116 conducted at the J9 gravity observatory in Strasbourg (France). In this intercomparison, we were able to check the meter scale factor with a high degree of precision by comparing them with 2 superconducting gravimeters and a FG5-type absolute ballistic gravimeter. It was also possible to carry out a detailed study of instrumental drift, a crucial topic for reliable monitoring of the long-term gravity variations in active volcanic areas. In fact, a challenge in time lapse gravimetry is the proper separation of the instrumental variations from real gravity changes eventually attributable to recharge or drainage processes of magma or fluids in the feeding systems of active volcanoes.Since 1980s the relative gravity network of Mt- Somma-Vesuvius has evolved over time becoming progressively larger and denser. We discuss the results of the time-lapse monitoring since 2003, when the INGV network reached an almost stable configuration. The retrieved field of time gravity change shows a pattern essentially related to the ground deformation detected by the permanent GNSS network. Vesuvius is currently experiencing subsidence at a variable rate. A clear topographic effect emerges with a strong correlation with altitude, whereby higher stations subside at a greater rate, up to 7 mm/year, than those at lower altitudes. Most of the observed gravity changes can be explained by this dynamics; only a residual positive gravity is detected in the western sector of the volcano, which could be likely due to hydrological effects. A reliable tidal gravity model was derived from the analysis of the gravity records. We believe that this result should help improve the accuracy of the volcano monitoring as it will be useful for the correct reduction of tidal effects for all relative and absolute gravity measurements acquired in the area.
Estimation of dichloromethane emissions in East Asia using recent high-altitude aircraft observations and synthesis inversion
Authors: Wang Zihao , Wilson Chris , Feng Wuhu , Li Ying , Hossaini Ryan , Atlas Elliot , Apel Eric , Oram David , Adcock Karina , Donnelly Stephen , Hendershot Roger , Hills Alan , Hornbrook Rebecca , Laube Johannes , Lueb Richard , Röckmann Thomas , Schauffler Sue , Smith Katie , Treadaway Victoria , Chipperfield Martyn
Published: February 2023

Although the Montreal Protocol has been successful in reducing the emissions of long-lived ozone-depleting substances, certain unregulated, chlorinated very short-lived substances (VSLS, lifetimes < 6 months) are believed to be having an increasing impact on stratospheric ozone depletion. The major sources of the chlorinated VSLS are anthropogenic. Emissions of chlorinated VSLS have been reported to be increasing from both bottom-up estimates and observations in recent years, among which dichloromethane (DCM) is the most abundant. Emissions from East Asia have been identified as contributing significantly to this increase (Oram et al., 2017; Claxton et al., 2020; Adcock et al., 2021; An et al., 2021).Here we use synthesis inversion to derive an estimation of DCM emissions with a focus on East Asia, with input from the TOMCAT/SLIMCAT 3-D offline chemical transport model (CTM), a gridded annual global emission estimate, and aircraft observations from three recent campaigns - POSIDON (2016, https://csl.noaa.gov/projects/posidon/), StratoClim (2017, http://www.stratoclim.org/), and ACCLIP (2021, https://www2.acom.ucar.edu/acclip). The CTM contains the production and loss of DCM and is driven by reanalysed meteorology (Chipperfield, 2006), with gridded emission field of DCM (Claxton et al., 2020). In the model we set up more source regions than previous studies based on prior information, transport pathways into stratosphere, and the distribution of major city clusters. The inversion is performed by finding the minimum of the cost function (Tarantola and Valette, 1982): xa = xb+ [GTR-1G + B-1]-1GTR-1[y - Gxb], where y has the observations, xb is the prior estimate, B and R are the error covariance matrix of the prior estimates and the observations respectively, and G is the sensitivity matrix, as an operator mapping the emissions onto the observations by the CTM. Then xa can be calculated as known as the posterior estimate. Coupling the model and observations, xa is considered the best estimate and reduces the errors in the prior estimate.We will present our analysis of DCM emissions up to the present day and compare them with previously published values and longer-term trends.References:Adcock et al., 2021, JGR Atmos., https://doi.org/10.1029/2020JD033137.An et al., 2021, Nat. Commun., https://doi.org/10.1038/s41467-021-27592-y.Chipperfield, 2006, QJR Meteorol. Soc., https://doi.org/10.1256/qj.05.51.Claxton et al., 2020, JGR Atmos., https://doi.org/10.1029/2019JD031818.Oram et al., 2017, ACP, https://doi.org/10.5194/acp-17-11929-2017.Tarantola and Valette,1982, Rev. Geophys., https://doi.org/10.1029/RG020i002p00219.
Internal structure of the evaporite sequence and its underground storage potential: case study from the northern part of the Polish Zechstein basin.
Authors: Tomaszczyk Marta , Adamuszek Marta , Czapowski Grzegorz
Published: February 2023

Due to the specific physical and mechanical properties of salt, the salt-bearing evaporite layers may be an attractive target for massive storage. Thick and homogeneous salt layers located between 500 and 1500 m below the surface in the tectonically inactive area are considered as the most suitable formations. In Poland, Leba Elevation located in the northern part of the Polish Zechstein Basin is often indicated as one of the regions with such a favourable geological condition for underground storage. In this region, the bedded salt deposits of the Werra cyclothem are located at a depth of 500-1100 m. The thickness of the rock salt layer, constrained mainly based on the data from over a hundred boreholes, shows variation between 0 and 220 m. However, the changes in the salt layer thickness demonstrate clear irregularity. An increase in the rock salt thickness correlates with a decrease in the anhydrite layer thickness. Previous analyses attribute the changes in the salt distribution to the different sedimentary environments, where the rock salt was deposited in the deeper parts of the basin, whereas the anhydrite was deposited in its shallower parts (Czapowski, 1987). In order to gain more information about the internal structure of the evaporite sequence and, in particular, the spatial variation in the rock salt thickness, we employ 2D seismic data. Based on our analysis, we evaluate the potential of the region for the underground storage and identified the areas with the highest potential. We compare our results with the analysis already presented in the literature.

Czapowski, G. (1987). Sedimentary facies in the Oldest Rock Salt (Na1) of the Leba elevation (northern Poland). In: Peryt, T.M. (eds) The Zechstein Facies in Europe. Lecture Notes in Earth Sciences, vol 10. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0011380
Central European temperature variations over the past two millennia recorded in a stalagmite from western Switzerland
Authors: Fleitmann Dominik , Häuselmann Anamaria D. , Cheng Hai , Leuenberger Markus , Affolter Stèphane
Published: February 2023

Almost all of the Central European temperature reconstructions covering the last two millennia reflect summer rather than mean annual air or cold season temperatures. To address the seasonal bias, we developed highly resolved 2000 year-long calcite isotope (δ18O) and fluid inclusion water isotope (δ2O and δ18O) records from a stalagmite from Milandre Cave in the Swiss Jura Mountains. Present-day climate in this region is strongly influenced by westerly air masses, making it an ideal site to record climate variability in the North Atlantic and European realm. Calibration of the Milandre Cave isotope records with historical and observational temperature and isotope data enables us to reconstruct mean annual air temperatures.  Our new temperature reconstruction shows temperature variations of approximately 2°C during the past two millennia, the temperature difference between the warmest decade of the Medieval Climate Anomaly (950–1250 CE) and the coldest decade of the Little Ice Age (1400–1700 CE) is around ~1.7°C. In general, higher central European temperatures were reconstructed in the periods 450–600 CE and 1000–1150 CE, and relatively low temperatures were recorded in the intervals 650–900 CE and 1350–1700 CE. Modelled cold season temperatures for the past millennium compare remarkably well with our reconstruction, and confirm the importance of both solar and internal forcing on Central European temperature.
Sustained old carbon dioxide release from river surfaces across an Andes to Amazon floodplain transect
Authors: Hilton Robert , West Josh , Garnett Mark , Dellinger Mathieu , Burt Emily
Published: February 2023

Globally, river surfaces release ~1.8 ± 0.3 PgC yr-1 of carbon dioxide (CO2). This is larger than the net removal of anthropogenic CO2 to the land surface of 1.6 ± 0.5 PgC yr-1, meaning that river CO2 could act as a leak of carbon back to the atmosphere over the coming decades. To better understand the impact of this large flux on the carbon cycle, we must seek to connect the geomorphic, hydrological and ecological controls on the export of carbon from the terrestrial biosphere, soils and rocks to river networks. Despite the recognition that the release of CO2 from river surfaces is substantial, we still lack insight on the source, delivery and/or production of CO2 along rivers. Here we assess the source of riverine CO2 along a ~250 km transect from the high Andes to the lowland Amazon floodplain, across the upper Madre de Dios basin in the wet season of March 2019. Using floating chamber methods, we quantify CO2 release from river surfaces. To explore the competition of CO2 sources from weathering (rock-derived C) and from the biosphere, we use a headspace method to trap CO2 on zeolite sieves for isotopic analysis (stable carbon isotopes and radiocarbon). The major and trace element dissolved chemistry was also assessed to quantify the dominant weathering reactions. We find downstream variability in CO2 release from river surfaces (ranging from ~650 to 2900 gC m-2 yr-1), with the mainstem of the Madre de Dios at our most downstream location having the highest flux. In contrast, the radiocarbon activity (reported as Fraction Modern, F14C) of the CO2 varied much less, with the two major tributaries the Rio Manu and Rio Alto Madre de Dios having F14C values of CO2 of 0.818 and 0.824, respectively, while ~150 km downstream the mainstem F14C of CO2 was 0.809. The F14C of a lowland river, not sourced from the Andes, had a F14C of CO2 of 0.954, suggesting old organic matter degradation may be underway upstream. Together with the stable C isotope composition and dissolved chemistry, these findings suggest a sustained release of old CO2 from carbonate weathering sources across this tropical floodplain transect, but that the overall flux is dominated by CO2 from the terrestrial biosphere that must be efficiently delivered to the river channel.
Instrumentation for laser ablation ionisation mass spectrometry on the lunar surface
Authors: Keresztes Schmidt Peter , Blaukovitsch Matthias , Boeren Nikita J. , Tulej Marek , Riedo Andreas , Wurz Peter
Published: February 2023

With NASA’s increased focus on exploration of our Moon within the Artemis program, new scientific goals have been formulated to expand our knowledge on the history of our Solar System, including the evolution of the Earth-Moon system. Additionally, establishing a permanent human presence on the Moon has been declared a goal of the Artemis program, the success of which will inevitably depend on in-situ resource utilization (ISRU) of lunar material. In turn, successful ISRU requires methods capable of analysing and selecting suitable materials in place. To support these tasks, sensitive instrumentation capable of determining the elemental and isotope composition of geological samples from the lunar surface is essential. Consequently, defining and determining the technical requirements of such instrumentation, constructing it accordingly, and verifying its performance are all crucial steps in maximising the scientific return of such a mission. Furthermore, NASA’s Artemis program also aims to facilitate future human exploration of Mars, which implies that instrumentation applied successfully on the Moon might find its application on the Martian surface in the future. We present our progress in designing, constructing and testing a prototype miniature laser ablation ionisation mass spectrometer (LIMS) for in-situ measurements on the lunar surface. The finalised instrument will be deployed on the Commercial Lunar Payload Service (CLPS) mission CP-22 scheduled for launch in late 2026 and land in the lunar south pole region. Our miniature reflectron-type time-of-flight mass analyser (160 mm x Ø 60 mm) designed for in-situ space applications was coupled to a pulsed Nd:YAG microchip laser system (SB1 series, Bright Microlaser Srl, Italy) operating at 532 nm (max. laser pulse energy of 40 µJ, pulse repetition rate of 100 Hz). The laser source and the optics were mounted colinearly to the optical axis of the instrument assembly into a cage system. This construction is modelled after the envisioned flight design, and therefore used to determine the required optical and electronic performance characteristics of the future flight instrument. The current flight design will be presented as well. Furthermore, validation of the technical implementation and verification of the scientific requirements will be discussed through the results of laser ablation experiments conducted on lunar regolith simulant.
Tropical Alpine Ecosystems under climate change: Paramos and moorlands in peril
Authors: Jaramillo Fernando , Rubiano Kristian , Clerici Nicola , Sánchez Adriana
Published: February 2023

Tropical Alpine Ecosystems are high-altitude grasslands located above 3000 m.a.s.l. along the tropical belt of three continents. Their unique vegetation and soil characteristics, in combination with low temperature and abundant precipitation, create the most advantageous conditions for regulating and storing surface and groundwater. However, increasing temperatures and changing patterns of precipitation due to greenhouse-gas-emission climate change are threatening these fragile environments, reducing their extent and modifying their altitudinal distribution range. Here, we investigate the impact of climate change on the distribution and extent of global Tropical Alpine Ecosystems. We use an ensemble of historical and projected climate data (SSP585) from seven General Circulation Models from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to estimate annual average values of temperature and annual accumulated values of precipitation for reference (1985-2014) and far future (2070-2100) 30-year periodos. We produced the 95% probability current and future hydroclimatic spaces for every ecosystem to determine the range at which Tropical Alpine Ecosystem currently thrives in the climatic space, and investigate a number of hydroclimatic variables. Then, we used the projected climate time-series data to assess the current Tropical Alpine Ecosystem areas that will be unable to keep up with the temperature and precipitation changes by exceeding their reference climatic boundaries in the far future. Overall, our results showed that the Tropical Alpine ecosystem would drastically reduce its extent. Approximately 45% of its current extent will experience hydroclimatic conditions beyond their reference climatic boundaries. For example, the Ethiopian montane moorlands in Africa will be the most impacted ecoregion with a reduction of approximately 95% of its current extent. For the case of páramos in the North of the South American continent, increasing temperatures and changing precipitation will render ~50% of the current extent unsuitable for these ecosystems during the dry season. Our results highlight the magnitude of the impacts of climate change on Tropical Alpine Ecosystem and the vulnerability of water security of millions of people who depend on its ecological functioning. These results also have implications for biodiversity conservation, as endemic species will be threatened by habitat reduction and shifts in their distribution ranges.