bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of manure separation on ammonia emission during storage and subsequent field application.
Authors: Holm Støckler Anna , Pedersen Johanna , Nørlem Kamp Jesper , Feilberg Anders , D. Hafner Sasha
Published: February 2023

Emission of ammonia from agriculture is a problem due to the negative effects on human health and natural ecosystems. Additionally, ammonia is a precursor for production of N2O in the atmosphere and is therefore an indirect greenhouse gas. A large part of ammonia emissions from agriculture originate from manure handling, which also reduces manure fertilizer value. Therefore, more knowledge on emissions from different types of manure and the effect of manure treatments are necessary to develop new measures to reduce ammonia emissions. Separating liquid manure (slurry) into a liquid and solid fraction can be used as a reduction technique for field application. The lower dry matter content of the liquid fraction may increase infiltration and decrease emission. Because separation might influence emissions during the storage period, this period must be considered along with the potential increased emissions from field application of the fiber fraction, when assessing the ammonia mitigation effect of separation. Here, data on ammonia emissions from storage and field application of raw and separated manure is presented. The manure types investigated were anaerobically digested manure and pig manure. Ammonia emissions from storage were measured with 1 m3 tanks constructed as dynamic flow chambers, and emissions after field application were measured with wind tunnels. Online measurements of ammonia concentrations were done with cavity ring-down spectrometry.       How the fiber fraction from the manure separation is utilized is important for the overall ammonia loss. Fiber can be stored in a pile and subsequently spread in the field. Another way to treat the fiber is to pyrolyze it into biochar which can be incorporated into the field as a strategy for long term carbon sequestration. It has been suggested to mix the biochar and manure prior to field application to limit operating costs with field driving. Therefore, during the field application experiments, a treatment with biochar added to the liquid fraction of manure was also investigated.
How Darcy-scale daemons lead theory developments for soil-water dynamics astray
Authors: Jackisch Conrad , Hohenbrink Tobias
Published: February 2023

Theory in soil physics is tightly bound to integral lab observations of dynamics of soil water content and matric potential. In addition, the perceptual model of (linear) filter flow water movement is deeply embedded in measurement procedures and projections of soil water dynamics. Such Darcy-scale principles have been found to mismatch with observations and application requirements at the landscape-scale including the effect of boundary conditions. While this discrepancy is often attributed to soil heterogeneity and the requirement for effective parameterisation, we seek to discuss that assumptions about scalability of lab-measured soil hydraulic properties taken out of the capillary context of soils potentially render our "physics" ill-posed.In this PICO we will present a series of analyses of soil water state dynamics from lab, plot and hillslope scales. We will show how scaling coincides with a change in boundary conditions and hydraulic gradients, which can fundamentally alter the inferred properties in similar soils at different locations. However, these effects are largely ignored when generalising soil-water constitutive theory and pedotransfer functions. We propose a scale- and information aware evaluation concept for pedotransfer function derivation and application. Given the many theoretical obstacles in scaling non-linear three-phase characteristics in porous media, we argue that reducing the scale-gap between the level of derivation and application of soil physical characteristics is more promising. A smart, standardised and repeatable field experiment at the pedon scale could be a first step towards a more physically consistent reference of macroscale soil functioning.

 
Interannual Variation of Land-Atmosphere Interactions and their Connection with Extremes over Europe
Authors: Jach Lisa , Schwitalla Thomas , Wulfmeyer Volker , Warrach-Sagi Kirsten
Published: February 2023

The land surface supplies heat and moisture to the atmosphere influencing the regional climate during the convective season. Availability of soil moisture for evapotranspiration, vegetation phenology and atmospheric conditions influence the strength of the land surface impact on the atmosphere, and the mechanisms predominating the heat and moisture exchange. As both the synoptic conditions as well as the vegetation state vary on sub-seasonal to interannual time scales, the strength of land-atmosphere (L-A) interaction is expected to fluctuate on these time scales.Up to now, research typically either focuses on case studies to understand the mechanisms of how land surface and atmosphere interact, or on climatic time scales to quantify co-variances in the climate system based on a sufficient sample size. Timescales in between remain rarely considered in land-atmosphere feedback studies.In our study, we applied various L-A coupling measures to evaluate land surface impacts on the atmosphere and quantify interactions associated with the triggering of convective precipitation and droughts for all summers between 1991 and 2022 over Europe based on ERA5 data.Our results highlight that differently strong L-A interactions evolve in dependence of atmospheric wetness, temperature, and the circulation pattern, as well as the root zone soil moisture and vegetation cover. Under warm and dry conditions such as in 2003, 2018 and 2022, soil moisture availability imposed limits for evapotranspiration not only in Southern Europe, but also in Central and Eastern Europe, interfering with vegetation growth and atmospheric moisture supply. Limited moisture and excessive heat supply amplified the already high temperatures and low near-surface moisture, which finally aggravated the unfavorable conditions for local precipitation and caused extreme drought conditions. On the contrary, warm and wet conditions such as in 2021 provided well-suited conditions for vegetation growth, which enhanced the moisture supply to the atmosphere. Together with stronger atmospheric instability, this provided more favorable preconditions for convective precipitation. Generally, most L-A interactions perform as an intensifier of persisting anomalies, particularly under warm and dry atmospheric conditions over Europe.
Improving and understanding probabilistic precipitation forecasts using machine learning
Authors: Brown Hannah , Haddad Stephen , Hopkinson Aaron , Roberts Nigel , Ramsdale Steven , Killick Peter
Published: February 2023

Uncertainty in numerical weather prediction (NWP) arises due to the initial state not being fully known and physical processes not being perfectly represented within the models. Precipitation is challenging to predict because it is non-linear with complex drivers from the atmosphere and so varies quickly even on a local scale. This means even advanced NWP models struggle to predict precipitation with the correct intensity at the right time or location. This study aims to explore whether machine learning (ML) can rediagnose precipitation rates based on vertical profiles of temperature, humidity and wind, thus replicating the precipitation calculated by cloud and precipitation parametrization schemes that are used in NWP models to represent the unresolved microphysical processes. A small but high-quality dataset comprised of days with widespread precipitation has been curated for developing an initial model, with in depth exploratory data analysis carried out to understand any trends in the model input data and assess the need for feature engineering. Vertical profiles of atmospheric variables (temperature, humidity, wind) taken from 6-hour forecasts of the Met Office Unified Model global ensemble (MOGREPS-G) provide input features for the ML model, and the target variable (or truth) is instantaneous precipitation intensity measured by the UK radar network at a 1km resolution. The two data sources are aligned onto the same grid by calculating the fractions of the MOGREPS-G ~20km cell containing radar precipitation in five precipitation intensity bands, with bounds informed by domain experts.Each MOGREPS-G ensemble member is used to generate a ML prediction of the fractional precipitation coverage that exceeds each intensity threshold, then an ensemble average of these fractions is calculated for each intensity threshold. These values can be considered as ML generated ensemble probabilities. They can then be compared with the true fractional coverage from radar, as well as precipitation probabilities from MOGREPS-G to identify similarities and differences in their behaviour. Explainable AI techniques are applied to better understand the decisions made by the ML model when creating predictions.  The aim is to understand the potential of using ML for improving precipitation forecasts, either through complementing NWP outputs with ML outputs, or by using ML as a tool for improving the understanding of the drivers of errors in NWP precipitation forecasts. Initial results look promising and a number of avenues for further development have been identified following consultation with domain experts.
Can pseudo waveforms from discrete point clouds represent the vertical structure of divergent canopies?
Authors: Tan Shen , Zhang Yao
Published: February 2023

Forest three-dimensional structure is important information for forest projection, and has shown promising applicability in simulating canopy radiative transfer. Light Detection And Ranging (LiDAR) technology provides a cost-effective way to retrieve forest structure. Compared with other methods, the pseudo-waveform (PWV) is a simpler but more robust way to obtain vertical structure information, but has only been tested in limited regions for two main limitations. First, given the cost of collecting in situ LiDAR observations, considering a comprehensive evaluation of the response of PWVs to canopy architecture remains impossible. Second, while radiative transfer models (RTMs) generate reasonable LiDAR signals, representing tree objects in a cost-effective way is still a bottleneck for large-scale simulation and analysis. As a necessary evaluation for retrieving forest structure from LiDAR, a light RTM was employed to simulate PWVs in this study. Based on the analysis, we aim to answer the following questions: 1) Can the tree objects be represented in a simpler way and with limited metrics, 2) Are the PWV responses reasonably to the variation in canopy architectures under uniform scenes, and 3) What is the PWV response to tree height uncertainties.
Communicating the return period of extremes
Authors: Ragno Elisa , AghaKouchak Amir
Published: February 2023

The concept of return period (recurrence interval) of extreme events is widely used in engineering practice and in the media. In engineering design and risk assessment, the concept of return period is used to determine the expected magnitude(s) of one or more extreme weather events – i.e., the expected magnitude of an event that, if occurred, might cause the failure of a structure. In the media, the concept of return period is used to communicate to the general public the severity of an event. For example, the 2021 summer flood in Northwestern Europe was reported in the news as a one-in-400-year event – an event expected on average once in 400 years. The strength of return period as a metric (in years) to describe the severity of events resides in the straightforward comparison between the average occurrence in years of an event with the average number of years a person can experience and recollect events.Generally, the return period of a rare event and its magnitude (known as return level) is inferred from limited observations - often derived by extrapolating from a distribution function fitted to the available observations. The distribution is often greatly influenced by the length of observations. These factors make the concept of return period prone to misinterpretation as extreme events are rarely observed in existing records.Here we provide a new perspective on the return period of extremes determined not only by its exceedance probability but also in relation to the observations used to describe the underlying distribution. Our method offers a straightforward metric, independent of the type of statistical distribution adopted, to quantify and communicate the likelihood of having observed the event of interest in the available observations, ranging from unlikely to very likely. This metric can provide a measure of confidence in the statistical inference of return periods based on the length of record used for inference. We argue that this additional information on likelihood offers important information for designers, planners, and decision-makers.
Microclimatic monitoring of the plaster casts of the Trajan’s Column in the Museum of Roman Civilisation (Rome)
Authors: Bubola Federica , Balliana Eleonora , Coletti Chiara , Cecamore Claudia , Parisi Presicce Claudio , Mazzoli Claudio
Published: February 2023

In recent years, the control of the micro-climate in museum environments or in historical buildings has assumed a role of great importance for the protection of the artefacts exhibited and for planning cost-effective and strategic preservation policy. The process of degradation indeed, defined as a result of progressive and cumulative material decay, strongly depends by environmental variables and their changes. Rapid changes and/or strong gradients in temperature and/or relative humidity, are the main causes of internal stress and of material surface detachments. Compared to new museums, historical ones often do not dispose of ideal conservation parameters, and they need specific conservation environments, considering the so-called historical climate, i.e. the microclimate to which the Cultural Heritage has adapted over the time. This is the case of the Museum of Roman Civilisation (Rome), which has been closed since 2014 and hosts a huge and valuable collection of plaster casts, such as those of the Trajan’s Column made by Napoleon III in 1861-1862 and gifted from Vatican City to Rome City Hall in 1953. In view of the imminent museum reopening and restoration, it is essential to define the actual level of microclimate quality, compared to the expected one, considering also economic and regulatory aspects and the future welfare of the artefacts. The research is focused on the response of the materials to the micro-climate by evaluating the incidence of temperature and relative humidity, presumably the main chemical and physical degradation factors for the plaster casts. A multidisciplinary diagnostic approach (i.e. Hyperspectral Imaging, Raman Spectroscopy, Infrared Spectroscopy) is also planned to characterise the constituent materials, to suppose the manufacturing techniques of the casts and to identify the degradation forms. The analysis of the complex interaction between the dynamics of the climate and the need for the conservation of the artefacts under conditions of maximum stability represents the starting point for proposing a sustainable restoration of the Trajan’s Column plaster casts of the Museum of Roman Civilisation and a future exhibition project that will allow their valorisation and exposure.
The contribution of Arctic marine heatwaves to the minimum sea ice extent as compound events
Authors: Barkhordarian Armineh , Nielsen David , Baehr Johanna
Published: February 2023

On the global scale, the frequency of marine heatwaves (MHWs) is projected to increase further in the twenty-first Century. In our earlier study we demonstrate that the high-impact major marine heatwaves over the northeast Pacific are co-located with a systematically-forced long-term warming pool, which we attribute to forcing by elevated greenhouse gases levels (GHG), and the recent industrial aerosol-load decrease (Barkhordarian et al., 2022).  In current study we show that the magnitude of Arctic MHWs has significantly increased since 2006, and has exceeded the pre-industrial climate bounds since then. We here perform statistical attribution methodologies, and provide a quantitative assessment of whether GHG forcing was necessary for the Arctic MHWs to occur, and whether it is a sufficient cause for such events to continue to repeatedly occur in the future.The probability of necessary causation of Arctic MHWs intensity, increases with increasing the severity of MHWs, and saturate to 1.0 by the time MHWs intensity exceeds the 2°C, indicating that any MHWs over the Arctic with an intensity higher than 2°C is entirely attributable to the inclusion of GHG forcing. These amplified extreme MHWs in the Arctic have each been accompanied by a record decline in Arctic Sea ice, in particular in the years 2007, 2012, 2016 and 2020. Over the last decade, MHWs occur in the Arctic where sea ice melt in June is 4 %/year faster, the ice-free season is ~3 months longer, the ocean heat-uptake is 50 W/m2 higher, and the sea surface temperature is ~2°C warmer, in comparison with the previous decade. In autumn surface evaporation rate is increasing, the increased low clouds favor more sea ice melt via emitting stronger longwave radiation. In summary, prolonged Arctic marine heatwaves, triggered by faster early summer sea ice melt, will accelerate Arctic warming, and cause Arctic Sea ice extent to shrink even faster in the near future.Barkhordarian, A., Nielsen, D.M. & Baehr, J. Recent marine heatwaves in the North Pacific warming pool can be attributed to rising atmospheric levels of greenhouse gases. Nature Communications Earth & Environment, 3, 131 (2022). https://doi.org/10.1038/s43247-022-00461-2 
A Semi-Lagrangian solver for the free surface Euler system with application to rotational wave flows
Authors: Alexandris-Galanopoulos Andreas , Belibassakis Kostas
Published: February 2023

Even though the majority of the classical water wave theory is restricted to potential flows, vortical flows are abundant in nature. This necessitates the need for the development of accurate and efficient methods for the simulation of rotational phenomena, such as the propagation of waves over bathymetry in the presence of a sheared current [1, 2].In the present work, a numerical method for the free surface Euler system with constant density and general bathymetry is developed within the frameworkof classical Computational Fluid Dynamics (CFD). Specifically, using the well known σ coordinate system, a layer-wise integration followed by an operatorsplitting is performed. The resulting horizontal advection component is, treated as a multilayered Shallow Water Equations (mSWE) system (see, e.g. [3]) and it is solved with a conventional Finite Volume solver. The vertical counterpart (that works similar to remeshing operator) regulates if the system is treated with a Lagrangian or an Eulerian approach. Finally, the dynamic pressure component coupled with the incompressibility constraint is treated using the well-known projection of Chorin [4].The method’s main advantages stem from its highly modular character that makes it both robust and easy to implement. The method’s performance is tested in the case of waves propagating on top of a sheared current. Results concerning the dispersion and propagation characteristics for general current profiles are presented and compared with other models [1,2,5].References[1] Julien Touboul and Kostas Belibassakis. A novel method for water waves propagating in the presence of vortical mean flows over variable bathymetry. Journal of Ocean Engineering and Marine Energy, 5(4):333–350, 2019[2] Kostas Belibassakis and Julien Touboul. A nonlinear coupled-mode model for waves propagating in vertically sheared currents in variablebathymetry—collinear waves and currents. Fluids, 4(2):61, 2019.[3] Fracois Bouchut and Vladimir Zeitlin. A robust well-balanced scheme for multi-layer shallow water equations. Discrete and Continuous DynamicalSystems-Series B, 13(4):739–758, 2010.[4] Zhe Liu, Lei Lin, Lian Xie, and Huiwang Gao. Partially implicit finite difference scheme for calculating dynamic pressure in a terrain-following coordinatenon-hydrostatic ocean model. Ocean Modelling, 106:44–57, 2016. [5] Ellingsen SA, Li Y (2017) Approximate dispersion relations for waves on arbitrary shear flows. J Geophys Res Oceans 122(12):9889–9905[5] Ellingsen SA, Li Y (2017) Approximate dispersion relations for waves on arbitrary shear flows. J Geophys Res Oceans 122(12):9889–9905
Identifying drivers of river floods using causal inference
Authors: Miersch Peter , Jiang Shijie , Rakovec Oldrich , Zscheischler Jakob
Published: February 2023

River floods are among the most devastating natural hazards, causing thousands of deaths and billions of euros in damages every year. Floods can result from a combination of compounding drivers such as heavy precipitation, snowmelt, and high antecedent soil moisture. These drivers and the processes they govern vary widely both between catchments and between flood events within a catchment, making a causal understanding of the underlying hydrological processes difficult.Modern causal inference methods, such as the PCMCI framework, are able to identify drivers from complex time series through causal discovery and build causally aware statistical models. However, causal inference tailored to extreme events remains a challenge due to data length limitations. To overcome data limitations, here we bridge the gap between synthetic and real world data using 1,000 years of simulated weather to drive as state-of-the-art hydrological model (the mesoscale Hydrological Model, mHM) over a wide range of European catchments. From the simulated time series, we extract high runoff events, on which we evaluate the causal inference approach. We identify the minimum data necessary for obtaining robust causal models, evaluate metrics for model evaluation and comparison, and compare causal flood drivers across catchments. Ultimately, this work will help establish best practices in causal inference for flood research to identify meteorological and catchment specific flood drivers in a changing climate.
Can spectral phenotypes discriminate subspecies? A case study at two European and Oriental beech forest stands
Authors: D'Odorico Petra , Schuman Meredith C. , Kurz Mirjam , Csilléry Katalin
Published: February 2023

Assisted migration programs, introducing new better adapted species at critical locations in our forests, have the potential to mitigate the adverse effects of climate change through the increase of forest diversity and resilience. While such measures entail ecological risks related with invasiveness of exotic species or outbreaks of new diseases, introducing close relatives of native species or populations from different parts of the species range is seen as the ecologically safer option. However, due to the similar appearance of closely related species, monitoring based on the external phenotype becomes difficult and leaves genetic screening as the only reliable, yet expensive option, limiting our ability to monitor large geographic areas. Reflectance spectroscopy has emerged as an important tool to assess plant functional trait distributions and taxonomic diversity, representing a rapid, scalable and integrated measure of the plant external and internal phenotype.Here, we examine the potential of leaf-level reflectance spectroscopy to discriminate between the subspecies European beech (Fagus sylvatica L.), and Oriental beech (Fagus sylvatica spp Orientalis (Lipsky) Greut. & Burd), which has been proposed as a potential candidate for assisted migration in European forests due to its greater genetic diversity and potentially higher drought tolerance. We investigated two European beech forests in France and Switzerland where Oriental beech from the Caucasus was introduced over 100 years ago next to European beech. Over the summers of 2021 and 2022, we measured leaf spectral reflectance and leaf morphological and biochemical traits from previously genotyped adult trees.Using least squares discriminant analysis (PLS-DA), we found that leaf spectral reflectance allowed the accurate discrimination of the two beech subspecies. In particular, we found that the short-wave-infrared (SWIR) region between 1450-1750 nm from top-of-canopy leaves provided the most accurate subspecies discrimination (BA = 0.86±0.08, k = 0.72±0.15). To provide a mechanistic basis of our findings, we estimated a suite of leaf traits based on spectra-derived indices and standard field and lab protocols. Phenotyping confirmed significant subspecies differences between traits that are known to govern light-plant interactions in the SWIR, including lignin, nitrogen in proteins, leaf mass per area and leaf thickness.Our study provides a basis for crown-level subspecies classifications from airborne or satellite-based imagery in the genus Fagus. Our findings provide an important starting point for the interpretation of variability in tree crown reflectance and the superior discrimination capacity we found for leaves at the top as compared to leaves at the bottom of the canopy, holds promise for the upscaling of the method using remote sensing.
The geodiversity mapping of Hungary
Authors: Pál Márton , Albert Gáspár
Published: February 2023

The assessment, evaluation, and visualisation of geodiversity is a useful tool when trying to consider geoscientific values for e.g. establishing a geopark or any geo-related tourism attraction. A comprehensive geodiversity analysis and mapping of the whole area of Hungary has not yet been carried out, even though there are two UNESCO Global Geoparks (UGGPs) and an aspiring UGGp in the country. In the present study we have gathered lithological, pedological, palaeontological, mineralogical, and landform data were collected and analysed following Pereira et al. (2013) and Pál & Albert (2021). The geodiversity map is an aggregation of all determined geoscientific subindices evaluated automatically in a GIS environment. Due to the medium scale of the source data, the diversity resolution of the generated map (geodatabase) corresponds to a 2 km grid, although the visualisation can be pseudo-isoline or heatmap style instead of displaying the grid cells.
The results support the delineation of the existing UGGPs and give hints about further abiotic nature conservation development opportunities. Due to the methodology applied, the assessment results and the map can be compared with similar maps in other countries. This quantitative evaluation is intended to serve as a benchmark for the Hungarian Geosite Inventory project currently in the planning phase, but the visualised map could also serve as a tool for promoting earth sciences in schools and existing geotourism centres.
 
MP was supported by the ÚNKP-22-3 New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research, Development and Innovation (NRDI) Fund. MP and GA was supported by project no. TKP2023-NVA-29 by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme.
Pereira, D.I., Pereira, P., Brilha, J., Santos, L. (2013): Geodiversity assessment of Paraná State (Brazil): An innovative approach. Environmental Management, vol. 52, pp. 541–552. DOI: 10.1007/s00267-013-0100-2
Pál, M., Albert, G (2021): Refinement Proposals for Geodiversity Assessment—A Case Study in the Bakony–Balaton UNESCO Global Geopark, Hungary. ISPRS Int. J. Geo-Inf. vol. 10, 566. DOI: 10.3390/ijgi100805
Intramolecular N2O isotopic composition using laser spectrometers: Correction functions, uncertainty budget, freeze-thaw events and source process identification
Authors: Wolf Benjamin , Xia Longlong , Smerald Andrew , Mohn Joachim , Kiese Ralf
Published: February 2023

N2O isotopic composition, i.e., δ15N-N2O, δ18O-N2O and especially site preference (SP; difference of substitution frequencies at terminal or central position in N-N-O molecule) has been shown to provide information on N2O source processes, and allows for source partitioning of N2O emissions to nitrification and denitrification. The advent of laser spectrometers more than a decade ago has spawned first datasets of N2O isotopic composition in daily resolution, but they have remained scarce. This is because until recently, the precision of commercially available spectrometers did not allow direct determination of N2O isotopic composition without technically challenging liquid nitrogen free cryogenic preconcentration of N2O. The specifications of the latest commercially available spectrometers promised preconcentration free in-situ determination of N2O isotopic composition, but a recent instrument intercomparison showed that for most of the analyzers, specific correction functions are still necessary. While some available instruments were thoroughly characterized with regard to short term precision, repeatability, drift, amount effects, matrix effects and spectral interferences, instrument performance during field deployment and on the time scale of long measurement campaigns has not been analysed so far.Here we present a setup and results of an automated chamber system in conjunction with a laser spectrometer that was installed in the field and in use for a period of approx. two years. Initially, amount dependence was in the range of 4 to 2 ‰ ppm N2O-1 for the various isotopic species, but instrument optimizations reduced this dependence to less than 1 ‰ ppm N2O-1. CH4 dependence was constant through the whole period and in the range of 1 to 2 ‰ ppm CH4-1, with affecting only δ15Nα and δ18O. In contrast, CO2 dependence was variable and in the same range as N2O amount dependence. The uncertainty budget was dominated by instrument noise, calibration and N2O amount dependence, indicating that improvements of instrument precision and availability of more suitable reference materials have a high potential to further decrease uncertainty of measurements. Analysis of the effect of uncertainty on the error of determined soil air N2O isotopic composition based on Keeling plots resulted in an error of 2 ‰ and 1 ‰ at N2O concentration increases of 70 and 140 ppb, respectively. Consequently, source partitioning based on SP will be associated with an error of 17 and less than 12% at the moment. Compared to growing-season emissions, SP and δ18O-N2O during freeze-thaw cycles were distinctly different. SP was ~0, indicating that N2O reduction to N2 was negligible during freeze-thaw events.
Marine geomodels from high-resolution seismic reflection data – a model ensemble approach
Authors: Mreyen Anne-Sophie , de la Varga Miguel , Nguyen Frédéric
Published: February 2023

Prior geological knowledge is crucial in a wide range of geophysical case studies aiming at data processing and interpretation. In this regard, geological modeling methods can be considered as efficient tools to facilitate petrophysical parametrization and constrain geophysical inversions as a priori information over a defined model space. We use the open-source library GemPy (De la Varga et al., 2019) which offers a community driven alternative based on the potential-field method and specialized in probabilistic modeling.In this work, we show an exemplary case study of high-resolution marine geophysical data comprising single-trace reflection and underwater refraction seismics validated with geotechnical data. Two approaches are suggested: (1) digitalization of geophysical imagery, i.e., spatial information from interpreted horizons and inherent uncertainties, and (2) pseudo depth migration of picked reflection seismic travel times using a simple velocity model from parallel recorded underwater refraction data. Next to a deterministic “best-fit” solution, the model is interpreted following probabilistic distributions of input data and classified after their identified certitudes (e.g., depth range of an observed seismic horizon), where prior knowledge is optionally included using Bayesian Networks. Finally, global uncertainties are estimated by multiple model realizations allowing for improved data assessment and enhanced decision making.The further outlook of this study is the creation of a variety of digital twins taking into account realistic conditions in terms of both, the geological environment as well as data acquisition, as a solid prior for future data exploitation by inverse processes of wave propagation in shallow marine environments.
Impact of climate change on groundwater levels in the Iberian Peninsula
Authors: Rouhani Amir , D'Oria Marco , Gómez-Hernández J. Jaime , Rode Michael , Jomaa Seifeddine
Published: February 2023

Groundwater represents a strategic freshwater resource for multiple sectors, including drinking water, agriculture production, and ecosystem services. The Mediterranean Basin is a well-known water-scarce region that is increasingly relying on groundwater use, especially during drought periods. Many areas in the Mediterranean region are already facing water stress due to increasing demand and limited resources. Climate change is likely to exacerbate these issues, as it is expected to lead to more frequent and severe drought conditions in some areas as well as irregular rainfall in others. Due to the growing availability of data and computational processing capabilities nowadays, deep learning models are seeing an increase in popularity. In this study, we attempted to create 92 location-specific Convolutional Neural Network (CNN) models in wells spatially distributed over the Iberian Peninsula to estimate groundwater levels until the end of the century. Our models use monthly precipitation and temperature data as input variables. Specifically, we considered cumulative precipitation for 3, 6, 12, 18, 24, and 36 months to account for the recharge time lag between precipitation and groundwater changes. Once trained using historical precipitation and temperature records, the CNNs were applied to assess the influence of climate change on groundwater levels. For future climate projections, an ensemble of six combinations of distinct General Circulation Models (GCMs) and Regional Climate Models (RCMs) was considered under two Representative Concentration Pathways (RCPs): the RCP4.5 and RCP8.5. Our preliminary results revealed a more consistent decline in groundwater levels in the southwest region of the Iberian Peninsula under the RCP8.5 scenario, while a general more constant groundwater level under the RCP4.5 scenario has been detected towards the end of the century. Detailed results of this study will be shared and discussed during the event.
Characterization of zircon megacrysts from an atypical occurrence of carbonatite at Kawisigamuwa, Sri Lanka
Authors: Gallhofer Daniela , Skrzypek Etienne , Hauzenberger Christoph , Möller Andreas , Andrew Joseph , Parra-Avila Luis A. , Martin Laure , Kemp Anthony , Fernando Rohan , Dengfeng He
Published: February 2023

Zircon megacrysts are unusually large crystals (> 5 mm) that are commonly associated with mantle-derived kimberlites, carbonatites, alkali basalts and syenitic pegmatites (e.g., Hoskin and Schaltegger 2003). Such zircons form during relatively short timespans and therefore, are often used as reference material for U-Pb geochronology. Here, we determine the geochemical and isotopic (U-Pb, Hf, O) characteristics of a little-known occurrence of zircon megacrysts at Kawisigamuwa, Sri Lanka.The dark brown megacrysts are euhedral, commonly elongate crystals with double pyramidal terminations and have faintly corroded crystal surfaces. The zircons consist of oscillatory zoned and nearly featureless cathodoluminescence-bright patches, some of which appear to follow sealed cracks. All zircon domains show a low to moderate FWHM of the ν3 (SiO4) Raman band (2.5 to 7.3 cm-1), have a low to moderate radiation damage (total α-dose mainly <0.5 x 1018 events/g) and therefore are intermediate to well crystalline. Contents of most trace element (U, Th, REE, P) are elevated in the oscillatory zoned domains, while Hf content is elevated in the CL-bright domains and seems to be grain-dependant. The oscillatory zoned domains yielded a TIMS weighted mean 206Pb/238U age of 532.39 ± 0.66 Ma (2sd). The206Pb/238U dates within the CL-bright domains are partially reset by a single event of recrystallisation at ~518 Ma. The mean Hafnium isotopic compositions of the tested grains show a narrow range of 176Hf/177Hf from 0.281969 to 0.282003. Oxygen isotopes determined on two oscillatory zoned zircon megacrysts are homogeneous (mean δ18O of 12.1 and 12.2).    While some of the trace and major element characteristics (Th/U, Zr/Hf, Hf content) of the Kawisigamuwa megacrysts resemble those of carbonatite zircons, their hafnium and oxygen isotope ratios are clearly different from mantle values. The isotopic values indicate that a significant amount of a crustal component must be involved in the formation of the zircons. Recently, several studies have found evidence for melting of carbonate rocks under high grade metamorphic conditions in Sri Lanka (e.g., Wang et al. 2021). It might be feasible that zircons grow from interaction of crustal derived carbonate melts and silicate melts or wall rocks under high grade metamorphic conditions.Hoskin P.W.O. and Schaltegger U. (2003). The Composition of Zircon and Igneous and Metamorphic Petrogenesis. Reviews in Mineralogy and Geochemistry, 53 (1), 27–62.Wang J., Su B.-X., Chen C., Ferrero S., Malaviarachchi S.P.K., Sakyi P.A., Yang Y.-H. and Dharmapriya P.L. (2021). Crustal derivation of the ca. 475-Ma Eppawala carbonatites in Sri Lanka. Journal of Petrology, 62 (11), 1-18.
Novel reef coral communities emerging after deep-time hyperthermal events
Authors: Dimitrijevic Danijela , Staples Timothy L. , Raja Nussaȉbah B. , Pandolfi John M. , Kiessling Wolfgang
Published: February 2023

Modern coral reefs are among the most vulnerable ecosystems to climate change. Accordingly, we hypothesize that past hyperthermal events had lasting impacts on reef coral communities. Specifically, novel communities are expected to emerge after ancient warming events, where novel communities are those that document a rapid and irreversible shift into a new state that differs in composition and/or function from past systems. To test our hypothesis, we used a global compilation of reef coral occurrences from the middle Triassic to modern times (244.08 Ma) and applied a rigorous novel community detection framework at 0.1 Myr time bins. Novelty is quantified based on two components – cumulative novelty (i.e., the deviation from historical baselines and instantaneous novelty (i.e., the magnitude of change relative to the previous state). A novel community state is identified when both cumulative and instantaneous novelty match in a time series of ecological change. Surprisingly, over the entire evolutionary history of scleractinian corals, there were only two novelty events at global scales, and they both occurred in the aftermath of hyperthermal events: The first in the Hettangian stage and the second in the Toarcian. Our results underscore the hypothesis that profound global warming can have lasting consequences on coral reef ecosystems. 
Seasonal pressurization of a coastal karst: the paleolithic decorated Cosquer cave (SE France)
Authors: Hugo Pellet , Pierre Henry , Bruno Arfib , Stéphanie Touron
Published: February 2023

The Cosquer cave is a paleolithic decorated cave, in a coastal karst linked to the sea. Stability of climatic parameters in caves is known to be one main condition for conservation of art. Hydroclimate data are measured since several years at a 5 minutes time step: karst air pressure, water level in the karst, atmospheric pressure and sea level. Data shows an unusual behaviour for a karst: the karst air pressure is nearly always higher than the atmospheric pressure. As a result, water level in the karst is below the sea level. Some rock art figures present on walls near water level undergo wash out and fading but limited thanks to the karst pressurization. A stop of this mechanism due to rising sea-level, an increase of the massif permeability or changes in climatic conditions would lead to the loss of arts near water bodies.The cave air overpressure is related to the rock permeability that should be low. The pressure time series show that three main processes drive the cave pressure. The daily variations of the sea tide provide an assessment of the cave air volume above the pools water level. Although the cave air is confined by the rock and the seawater, there are external air inflows during short pressurization events, that can be deduced from pressure data. Then, the low cave air pressure decrease over the summer season is explained by air outflow through the rock. A bulk permeability is then calculated using Darcy law, assuming a gas permeability in a non-saturated medium. Three theoretical cases are evaluated: an equivalent porous medium, a single fracture, and a single karst conduit. The time series give an observation database to assess future changes in the pressure behaviour of this decorated paleolithic cave, and to detect water level increase and adjust conservation choices.
Sensitivity of Folgefonna ice cap to anthropogenic climate change
Authors: Frøystad Rebekka , Born Andreas
Published: February 2023

Glaciers in Norway are retreating, following the global trend caused by climate change. Future mass loss is projected to increase and cause the majority of Norwegian glaciers to disappear by the end of the century. This alters runoff and downstream hydrology, thus affecting available water resources for local communities. Quantifying this future change is essential to aid societal climate adaptation.In this work, our aim is to assess both the rate of change and how trustworthy these estimates are given uncertainty in future climate and simulation tools. We organize the study around the Folgefonna ice cap in Western Norway, a prime example of a maritime ice cap. For the people living in its vicinity, the ice cap is important as it acts as a reservoir for both hydropower generation and drinking water. Despite this, little is known about how it will change in the future.Using the model BESSI (The Bergen Snow Simulator), we simulate the surface mass balance of Folgefonna at a high spatial resolution. Recent developments of BESSI have made it a suitable option for small-scale glacier studies. These model alterations are presented here as well as results of past and future surface mass balance for the ice cap. We quantify how sensitive Folgefonna is to climate change and discuss limitations to the tools available for future glacier projections.
How did DANA event affect water status and thermal response of fruit crops?
Authors: Conesa María R. , Conejero Wenceslao , Mira-García Ana B. , Vera Juan , Ruiz-Sánchez Mª Carmen
Published: February 2023

In recent years, associated extreme events to climate change are being experienced more frequently and with greater intensity, worldwide but particularly affecting to Mediterranean basin countries. The DANA phenomenon (Spanish acronym for depresión aislada en niveles altos, meaning upper-level isolated atmospheric depression) occurs normally in autumn due to convective storms generated by the existence of cold air in the upper layers of the atmosphere combined with warm winds coming from the Mediterranean Sea. Its effects are devastating, provoking storms of great intensity that cause violent flash-flooding and run-off with a huge capacity for soil erosion. This field experiment focuses on the effects of DANA event of 12-13 September 2019 in Southern Spain on plant water status and thermal response of nectarine trees. Two irrigation treatments were applied during the summer-autumn postharvest (DOY, Day of the year, 158-329): well-irrigated (CTL) and non-irrigated (DRY). Volumetric soil water content (θv), air temperature (Ta) and canopy temperature (Tc) were real-time monitored and the crop water stress index (CWSI) was calculated. Stem water potential (Ψstem) and leaf gas exchange were measured on representative days of the experimental period. The effects of DANA forced to disconnect the soil water content sensors, precluding to measure Ψstem and leaf gas exchange from DOY 255 to 275. Before DANA, withholding irrigation caused a gradual decline in soil and plant water status in the DRY treatment. Minimum values of Ψstem = -2.63 MPa and θv = 13% were obtained at DOY 246. Significant differences were obtained in the Tc, Tc-Ta, and CWSI between treatments. CWSI in the DRY treatment was maximum (0.94) at DOY 232. The effects of DANA reduced the differences between treatments in thermal data, what required to establish different baselines for CWSI calculation. In this sense, the relationship Tc-Ta vs. VPD improved the coefficient of determination after DANA (from R2=0.71*** to 0.83***) in well-irrigated trees. Similar values of Ψstem and leaf gas exchange were found in both treatments after DANA. Only thermal indices showed significant differences between treatments. Furthermore, the strong relationship found between Tc-Ta vs. Ψstem worsened after DANA event (from R2=0.81*** to 0.32*). This work underlined the robustness of infra-red thermography to continuously monitor plant water status under this type of natural weather disaster.   Acknowledgements: This work was funded by Spanish Agencia Estatal de Investigación (PID2019-106226RB-C21/AEI/10.13039/501100011033). MR. Conesa thanks to the Spanish Juan de la Cierva programme (IJC2020-045450-I) funded by MCIN/AEI/10.13039/501100011033 and European Union NextGenerationEU/PRTR.  
SPECIES: a balloon-borne and airborne instrument coupling infrared lasers with Optical Feedback Cavity Enhanced Absorption Spectroscopy technique for atmospheric in-situ trace-gas measurements
Authors: Catoire Valery , Jacquet Patrick , Chartier Michel , Romanini Daniele , Krysztofiak Gisèle , Ventrillard Irène , Robert Claude
Published: February 2023

The balloon-borne and airborne instrument SPECIES (SPECtromètre Infrarouge à lasErs in Situ) recently built in our laboratory will be described. This is a mid-infrared absorption spectrometer, including four channels by coupling Interband or Quantum Cascade Lasers (ICLs or QCLs) to Optical-Feedback Cavity-Enhanced Absorption Spectroscopy (OF-CEAS). Using cavities of 50 cm length, this leads to very high resolution (< 0.005 cm-1) spectra and very long optical paths (> 5 km) and thus, low detection limits for the trace gases to be measured. It can contribute to the detailed description and understanding of the functioning of the free troposphere and stratosphere in terms of composition, chemical reactivity and circulation of air masses by carrying out fast (< 2 s) in-situ measurements of reactive trace gases and greenhouse gases among CO, NOx, CH2O, 12CO2, 13CO2, CH4 and N2O, at very high spatial resolution, i.e. a few meters vertically or hundred meters horizontally. Mini-SPECIES is the lightened version of SPECIES, comprising two lasers coupled to two cavities and reduced electrical power, which allows its integration in aircraft or its operation for long-duration stratospheric balloon flights (> 4 days). High accuracies are obtained when calibration in flight, or at ground before and after the flight, is performed against standards. In addition to providing reference measurements for calibration/validation of space missions, these performances can lead to in-depth characterization of particular atmospheric processes.