bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil Lipidomics: A LC-MS/MS based workflow with advanced data processing for biomarker discovery in soil communities
Authors: Samrat Rahul , Wanek Wolfgang
Published: February 2023

The vital role played by soil microbial communities, including bacteria, fungi, and other microorganisms, in the provision of several essential terrestrial ecosystem services cannot be overstated. To gain a more comprehensive understanding of their multifaceted ecosystem services, it is essential to identify and examine the functional role of these microbial communities and of the pathways by which they facilitate soil organic matter and plant necromass decomposition and nutrient cycling. The determination of microbial community composition in soils, and extending this to the complex decomposer soil food web, has remained a significant challenge. To address this challenge, various techniques such as 16S and 18S rRNA gene sequencing and phospholipid fatty acid (PLFA)-based biomarker analysis have been applied. While PLFA analysis has been used to characterize these communities for over three decades, recent advancements in liquid chromatography (LC) and high-resolution mass spectrometry (HRMS) now enable comprehensive analysis of the soil lipidome based on intact polar lipids, providing greater though unknown opportunities to discover biomarkers of soil microbes and other food web members. In light of this, we developed an untargeted lipidomics workflow using reverse phase liquid chromatography and electrospray ionization tandem mass spectrometry (RPLC ESI MSMS) for the analysis of lipidomes in soil and pure cultures of archaeal, bacterial, and fungal organisms, to be extended to soil fauna and plants. This workflow includes techniques for the rapid and accurate identification and quantification of lipid molecules in complex samples, utilizing internal standards, quality control strategies, Orbitrap based instrument setups, and an advanced data processing pipeline. Key features of the pipeline include compound annotation for unknowns based on SMILES generation, retention time prediction, feature-based molecular networking, as well as the relative quantification of these compounds using ionization efficiency prediction models. The developed method was capable of analyzing and identifying over 2000 unique intact polar lipid molecules from more than 12 classes in a variety of samples, covering Archaea, Gram-positive and Gram-negative bacteria, fungi, arthropods, algae and higher plants. Thus, our method can provide valuable insights into the complex and diverse soil food web by accurately identifying and quantifying a wide range of intact polar lipid molecules and further can be used for biomarker analysis and isotope tracing in soil microbial communities.
Destination Earth On-Demand Extremes Digital Twin
Authors: Randriamampianina Roger ,   On-Demand Extremes Digital Twin Team
Published: February 2023

Destination Earth (DE) On-Demand Extremes Digital Twin (DT) (DE_330_MF) offers configurable digital twin engines for forecasting environmental extremes at a sub-km scale. DE_330_MF aims at providing an on-demand workflow with co-design of high resolution predictions about extreme weather events combined with decision making support for impact sectors including hydrology, air quality and energy meteorology, with the use of a physics-based and data driven model system and computationally-intensive data-flow organised on the EuroHPC high performance computing platform. 
The DE_330_MF core software system is developed in four parts. Firstly, code adaptation needed for running on hybrid CPU and accelerator architectures will be done. Here, our most computationally intensive parts will be optimised for running on accelerators at the end of the first phase. Secondly, our modelling system is being adapted for running on a sub-km grid scale in an efficient on-demand setup. During phase 1 we primarily use operationally and pre-operationally mature components. Tailor-made modules targeted on impact modelling (e.g. wind energy) will be implemented as well. Thirdly, we work on post-processing of the model output, so that this can be distilled into a limited number of variables essential for end-users including uncertainty quantification for these variables. The approaches will be tailor-made for the specific targeted types of extreme events. Triggers for detecting extreme events are being developed as part of the post-processing work. Fourthly, and very importantly, we are designing and developing workflow management tools and scripting for the core software. Input and output data are also managed, with a particular focus on the exploitation of using high-density observations in high-resolution weather forecasting and verification. Overall we aim at running a hectometric scale On-Demand Extremes DT with a typical resolution of 750 or 500 m, exploring a finer resolution of up to 200 m for special applications where it is meaningful. In the first phase, capability demonstration is the focus by examining a range of carefully selected high-impact cases for the three above-mentioned impact areas, as well as other applications such as agriculture. The goal here is to explore the added values with co-designing workflow combining the on-demand, event- or user-driven solutions with weather forecasting on the one hand, and impact sectors on the other hand, in an integrated value chain for decision-making support. In this effort, containerised solutions, including one hydrological and two air quality models, will run next (one way coupling) to the on-demand extremes DT.
This work is funded by the EU under agreement DE_330_MF between ECMWF and Météo-France. The on-demand capability proposed by the Météo-France led international partnership is a key component of the weather-induced extremes digital twin, which ECMWF will deliver in the first phase of Destination Earth, launched by the EC.
Stochastic weather generator and deep learning approach for predicting and sampling extreme European heatwaves
Authors: Miloshevich George , Lucente Dario , Bouchet Freddy , Yiou Pascal
Published: February 2023

Sampling rare events such as extreme heatwaves whose return period is larger than the length of available observations requires developing and benchmarking new  simulation methods. There is growing interest in applying deep learning alongside already existing statistical approaches to better generate and predict rare events. Our goal is to benchmark Stochastic Weather Generator (SWG) [1] based on analogs of circulation, soil moisture and temperature as a tool for sampling tails of distribution as well as forecasting heatwaves in France and Scandinavia using data from General Circulation Model (GCM). Analog method has been successfully implemented in rare event algorithms for low dimensional climate models [2]. SWG is implemented using a Markov chain with hidden states (.e.g. geopotential height at 500 hPa) with Euclidean metric. When applying such methods to climate data two challenges emerge: a large number of degrees of freedom and the difficulty of including slow drivers such as soil moisture alongside circulation patterns. Consequently, we are going to discuss ways of adjusting the distance metric of the analog Markov chain and dimensionality reduction techniques such as EOFs and variational auto encoder. By choosing the correct combination of weighted variables in the Euclidean metric and using analogs of only 100 years and generating long synthetic sequences we are able to correctly estimate return times of order 7000 years, which is validated based on a 7200 year long control run. The teleconnection patterns generated thus also look reliable compared to the control run. Next we compare SWG forecasts of heatwaves with a direct supervised approach based on a Convolutional Neural Network (CNN). Both CNN and SWG are trained and validated on exactly the same GCM runs which allows us to conclude that CNN performs better in both regions. One could consider SWG as a baseline approach for CNN for this task.[1] Yiou, P. and Jézéquel, A., https://doi.org/10.5194/gmd-13-763-2020, 2020[2] D. Lucente at al. https://10.1088/1742-5468/ac7aa7, 2022[3] DP Kingma, M Welling - https://doi.org/10.48550/arXiv.1312.6114, 2013[4] G. Miloshevich, at al - https://doi.org/10.48550/arXiv.2208.00971, 2022
Improving the CO2 storage measurements in a tall temperate forest
Authors: Gorlenko Anastasia , Ibrom Andreas
Published: February 2023

The storage change term is calculated to account for the CO2 accumulation in the air column underneath the eddy covariance system when calculating net surface exchange. The rigorous form requires continuous measurements in space and time. Historically, a standard approximation was to measure CO2 concentrations solely at one point, the eddy covariance system measurement height. Since the storage term can contribute significantly to annual fluxes, e.g., the Net Ecosystem Exchange of CO2, other methods have been investigated, such as the vertically distributed measurements within a profile system.This work aims at providing a physically sound storage change calculation method for long-term atmospheric stations such as ICOS. Additionally, the extrapolation to historical time series brings the possibility to correct the storage term when only the one-point measurements were available.We used one year of eddy covariance and profile system data collected in the Sorø temperate forest in Denmark and compared different methods to calculate the storage change. We compared the top tower measurements with the results from the vertical profile system. We also considered the temporal resolution by contrasting two methods to average the samples: subtracting the end and beginning concentrations as the first method and using the times series linear regression slope as the second. We highlighted the effects on annual budgets, surface fluxes, and the interactions with other turbulence-driven variables, namely the friction velocity and the standard deviation of vertical velocity fluctuations.These results are thus relevant for high canopies and other landscapes investigated with tall towers, where the storage change is expected to impact the annual budgets considerably.
What causes rising DOC concentrations in streams from peat-affected catchments? Insights with high-resolution water quality analysis
Authors: Houska Tobias , Degenkolb Laura , Brösing Marc , Müller Ingo , Kaiser Klaus , Knorr Klaus-Holger , Lau Maximilian , Jackisch Conrad , Kalbitz Karsten
Published: February 2023

Peatlands are an important natural terrestrial carbon store. Any impacts on the drivers of hydro-biogeochemical processes in these ecosystems can be particularly severe. Climate change and degradation through drainages and ditches are changing peatlands dramatically. Degraded peats turn from powerful carbon sinks to emitters. They can also threaten drinking water supplies, as (heavy) metals can be leached from degraded peats along with dissolved organic carbon (DOC). However, quantifying DOC discharges from terrestrial to aquatic ecosystems is challenging. The hydro-biogeochemical processes occurring at the soil-aquatic interface are not only complex but also occur at different spatial and temporal scales. These processes depend on a variety of constantly changing external conditions such as temperature, nutrition- as well as oxygen availability. On top, there is no sensor available, which can measure the DOC concentrations of streams in situ and directly.Here we investigated the DOC concentration in two nested catchments of two adjacent streams in the Ore Mountains of southern Saxony in Germany. One stream is dominated by mineral soils, while the other is dominated by (degraded) peat soils. Each of the four sites is equipped with YSI-EXO fDOM sensors. Further data comprise discharge, water temperature, turbidity and electric conductivity. A machine-learning algorithm (Random Forest) was trained to predict DOC concentration from the available data set (validation r² between 0.85 and 0.98). We investigated the gained 15-minute resolution DOC data on potential driving factors. Interestingly, the area-specific loads of the peat-dominated catchment with 3.5 mg C m-2 a-1 did not differ significantly from that of the mineral soil-dominated catchment with 3.1 mg C m-2 a-1. However, the loads over the year were almost twice as high as previously detected from data collected on a monthly basis. With the high-resolution DOC data, we can detect the drivers of extreme DOC concentrations (up to 40 mg l-1) after heavy rainfall events in summer and constant high-level DOC concentrations of 20 mg l-1 during snowmelt in winter. By applying the algorithm on DOC:DON ratios, we were further able to quantify the different sources of plant-based material from the peat soils and microbial-degraded material from the mineral soil-dominated catchment.Previous DOC measurements, mostly based on 2-week to monthly measurements, likely greatly underestimate the contribution of DOC to C fluxes in ecosystems. For C-rich ecosystems such as Peatlands, this is particularly significant.
Immediate effects of the Hunga Tonga - Hunga Ha’apai volcanic eruption on the AC and DC Global Electric Circuits
Authors: Bór József , Bozóki Tamás , Sátori Gabriella , Williams Earle R. , Behnke Sonja Ann , Rycroft Michael , Buzás Attila , Silva Hugo Gonçalves , Kubicki Marek , Said Ryan , Vagasky Chris , Steinbach Péter , Szabone André Karolina , Atkinson Mike
Published: February 2023

Observed responses of the AC and DC parts of the Global Electric Circuit (GEC) to the large eruption of the Hunga Tonga - Hunga Ha’apai (HT-HH) volcano on 15 January, 2022 are presented. The AC-related investigation is based on Schumann resonance (SR) measurements from the Nagycenk Geophysical Observatory (NCK), Hungary as well as from distant stations on the globe belonging to the HeartMath Institute (https://www.heartmath.org/gci/). The DC-related investigation is based on atmospheric electric potential gradient measurements (PG) from six recording stations in Europe and in the USA. The GLD360 and the WWLLN lightning detection networks were used to characterize lightning activity in the vicinity of the HT-HH island on the investigated day. The peak lightning stroke rate reached 80/s (5000/minute), whereas the average global rate is ~44/s. Lightning discharges occurred in rings around the vent of the volcano. Peak currents and the diameter of the ring of positive and negative polarity lightning strokes varied differently in the main phase of the eruption. At its peak, negative lightning dominated the electric activity in the volcanic cloud.A global intensification of SR is apparent in connection with the enhanced lightning activity caused by the eruption. The SR data together with the global network observations indicate that the lightning activity in the eruption dominates the naturally occurring global activity for a period of at least one hour. The highly localized increase in lightning activity over HT-HH provides a unique point source of excitation for the SR.In contrast with the dramatic response of the AC global circuit, the response of the DC GEC to this exceptional eruption is not readily unambiguous in the PG measurements. The observations suggest that impulse-like charging of the GEC by ~15% via -CG lightning strokes took place two times during the eruption. A time constant of 7 or 8 minutes has been inferred for near-surface electric field changes from these enhancements. This could be the first direct measurement of the time constant of the GEC near the Earth’s surface, as well as the first observation of the direct charging of the DC GEC by a single atmospheric electrified source.
Measuring spontaneous charging of single aerosol particles
Authors: Stoellner Andrea , Lenton Isaac , Muller Caroline , Waitukaitis Scott
Published: February 2023

            Charge accumulation on aerosol particles (including water droplets) plays a critical role in a variety of natural and industrial processes. It gives rise to lightning in thunder- and sandstorms, influences particle transport and interactions in the atmosphere and can lead to dangerous dust explosions during industrial processing [1]. Shavlov et al. [2] suggest that the hydroxide ions and protons formed by the dissociation of water molecules are sufficient to cause charging during evaporation and condensation of droplets or surface-adsorbed water on solid particles. This hypothesis is backed up by Moreira et al. [3] who find that liquid evaporation leads to charge buildup on dielectric surfaces.            By levitating individual aerosol particles in an optical trap we can characterize and manipulate the particle without losing information to ensemble averages or external interference from other particles or substrates [4, 5]. Our setup allows for trapping of various types of solid and liquid particles in the micrometer size range, like silica spheres, water droplets or droplets with solid nuclei inside. Figure 1 shows an illustration of the measurement principle. The particle’s charge is measured by applying a sinusoidal electric field and observing the resulting particle motion. The Mie scattering pattern of the particle furthermore gives information about the particle’s size and refractive index, both at equilibrium and during evaporation and condensation. The experiment allows us to control the relative humidity and air ion concentration around as well as air flow across the particle.Ultimately we hope to contribute to a better understanding of the microphysical processes involved in thundercloud electrification and adjacent electrical phenomena in the atmosphere.  FIGURE 1. Optical tweezers (λ = 532 nm) holding a solid or liquid aerosol particle. A sinusoidal electric field is applied between the two electrodes and the resulting particle motion as well as the particle’s Mie scattering pattern are recorded.AcknowledgmentsThis project has received funding from the European Research Council (ERC) under the European Union’s Starting Grant (No. 949120).ReferencesZhang L., et al. (2016) Indoor Built Environ 25 (3) 437-440.
Shavlov A. et al. (2018) J Aerosol Sci. 123 17-26.
Moreira K. S., et al. (2020) Mater. Interfaces 7(18) 202000884.
Reich O., et al. (2020) Phys. 3(1).
Ricci F., et al. (2022) ACS Nano 6 (16) 8677–8683.
Subpolar Atlantic Meridional Overturning in Community Earth System Model (CESM): setting up the further experiment
Authors: Fedorov Aleksandr M. , de Jong M. Femke , Wieners Claudia E. , Dijkstra Henk A.
Published: February 2023

The Atlantic Meridional Overturning Circulation (AMOC) is a three-dimensional system of ocean currents contributing to a relatively mild climate in northern Europe. AMOC transports vary on a range of time scales, from centennial to daily. Despite a wide history of research on AMOC variability from both measurements and modeling perspectives, the role of atmospheric noise in subseasonal and intra-annual AMOC variations remains unclear. In the current study, we describe the modeling experiment planned to reveal the importance of mesoscale winds around the southern tip of Greenland, named Tip Jets, in  AMOC variability. Tip Jet wind events have no regularity in frequency and intensity, they mostly depend on the Icelandic Low location and are partly associated with a positive NAO phase in winter. The experiment design is based on implying the perturbations in the momentum, heat, and freshwater forcing associated with Tip Jet events. Therefore, we constructed the composite Tip Jet forcing using daily ERA5 (25 km, December-March, 1969-2019) wind, surface fluxes, and precipitation/evaporation rates. These composite fields of anomalies are planned to be added to the CESM-derived climatology to describe the possible response of the AMOC system to these types of noise forcing. Setting up the experiment included the model verification based on the comparison between the monthly output from the ~0.1 ° CESM Parallel Ocean Product (POP) simulations and the observational OSNAP array that combines measurements along the line between Labrador, Greenland, and the European shelf. The mean state of the atmosphere from CESM (50 km, monthly) was compared to the ERA5 (25 km, monthly). Generally, the CESM model reproduces the AMOC at OSNAP well. In conclusion, this preliminary research shows that AMOC is well simulated by the Community Earth System Model in the Subpolar North Atlantic. Also, the current research proposes patterns of noise forcing over the North Atlantic Subpolar Gyre that will be used in further modeling experiments.
Contribution of spatial features for classifying seismic events from Distributed Acoustic Sensing (DAS) data streams
Authors: Huynh Camille , Hibert Clément , Jestin Camille , Malet Jean-Philippe , Lanticq Vincent
Published: February 2023

Distributed Acoustic Sensing (DAS) is an acoustic sensor instrument that turns a single optical fiber into a dense array of thousands of equally spaced seismometers. Geoscientists and companies have an interest in investing in DAS technologies for better understanding the Earth by observing natural and anthropogenic seismic events or assisting in large infrastructure monitoring with low installation and maintenance costs. However, this type of instrument generates a significantly larger amount of data than conventional seismometers, data that can be complex to store, exploit and interpret.Several strategies for classifying seismic events from fiber-optics DAS data exist in the scientific literature. Conventional approaches rely on the use of features that describe the waveforms and frequency content of signals recorded individually at virtual stations along the fiber; they do not integrate the spatial density of information permitted by DAS. Several studies on dense seismological arrays have introduced similarity measures between the different time series data such as cross-correlations, dynamic time warping (DTW) or compression-based dissimilarity.This study aims to quantify the contribution of spatial features for DAS data streams classification. We have chosen to explore spatial features related to both standard statistical measures (e.g., spatial mean, median, skewness, kurtosis), and advanced signal processing measures (e.g., auto-correlations, cross-correlations, DTW). This set of measures allows enriching a list of already used time series features which includes waveform, spectrum and spectrogram. A Random Forest (RF) classifier is then trained, and a Random Markov Field (RMF) algorithm is used after classification to account for redundant spatial and temporal information.The evaluation of the spatial feature contribution is based on the output of the RF-RMF processing chain. Anthropogenically-triggered seismic data were acquired at the FEBUS Optics test bench. We consider five seismic sources: footsteps, impacts, excavators, compactor and fluid leaks. A class of noise is added as the RF-RMF algorithm is developed for processing DAS streams inherently affected by  noise.  Accurate  classification results can be obtained using only time features, and ongoing tests show a 2% increase in the correct classification rate with the use of both time and spatial features. The improvement allowed by the addition of spatial features is tangible but limited on our test dataset, but we think it should have a much greater impact on natural sources and we will discuss this perspective.
Analysis of six years of GIC measurements in the Austrian power grid
Authors: Bailey Rachel , Schachinger Philipp , Albert Dennis , Achleitner Georg , Leonhardt Roman
Published: February 2023

Geomagnetically induced currents (GICs) are a consequence of space weather activity that can affect power grid operation and stability worldwide. GICs manifest as quasi-direct currents flowing between the power grids and the conductive earth, and are often measured with a Hall sensor placed at the transformer neutral. Globally, the number of power grid substations with GIC measurements has grown quickly in recent years, but Austria remains one of the few countries with a dataset of long-term GIC observations. GIC measurements in substations in the Austrian power grid have been carried out since 2016, with a maximum of seven concurrent substation measurements, providing a unique opportunity for GIC measurement analysis.In this study, we present an analysis of the last six years of GIC measurements in Austria. Seven custom-built stand-alone GIC measurement systems have been installed in the 220 and 380 kV transmission levels, measuring currents up to 25 A. We identify recurrent geomagnetic activity in the measurements, and also find man-made sources of low frequency currents using frequency analysis. We focus on two geomagnetic storms from September 2017 and May 2021 to discuss the effects of GICs on a mid-latitude power transmission grid. In conclusion, we find that there is a daily level of noise in the data and that, even during the largest events when 14 A were measured, transformer heating remains unlikely.
Does freshwater content of the East Greenland Current show imprints of increasing meltwater runoff?
Authors: Schiller-Weiss Ilana , Martin Torge , Karstensen Johannes , Biastoch Arne
Published: February 2023

Accelerated melting of the Greenland Ice Sheet has been identified as a tipping element in the freshwater balance of the subpolar North Atlantic (SPNA), where the East Greenland Current is a primary pathway for transporting Arctic-sourced freshwater and Greenland glacial meltwater. Understanding the freshwater variability of the East Greenland Current (EGC) and Coastal Current (EGCC) and their interaction is of high importance, as these gather the imprint of ice melt once the meltwater leaves the fjords and enters the open ocean. Using a high-resolution model (VIKING20X, 1/20°) and gridded, observational assimilated reanalysis (GLORYS12, 1/12°), we find the freshest water remains close to the shelf with interannual extremes in freshwater content attributable to the imprint of Greenland melt only in years 2010 and 2012. This signal is only found in the VIKING20X simulation, which in contrast to GLORYS12 uses realistic, interannually varying runoff forcing including estimates of the Greenland Ice Sheet mass balance. We further discuss the role of wind forcing, sea ice melt, and Greenland runoff, which all contribute to variability in freshwater content along the boundary current.Our results show that slackened alongshore winds reduce onshore Ekman transport allowing for freshwater to spread laterally in the EGC, while stronger alongshore winds constrain freshwater closer to the shelf with saline intrusions from the interior basin into the outer EGC. South of ~65°N sea ice melts year round and retreats northward with melting occurring only in summer. Associated salinity and thus freshwater content anomalies are of similar magnitude as those associated with meltwater runoff and overlap in both seasonal timing and advective time scales. This could explain the challenges to identify freshening events originating from extreme melt events on the Greenland Ice Sheet at currently observed magnitudes. Their detection is critically dependent on synoptic and interannually varying processes. Our findings also suggest that ocean models or model-based reanalysis products aiming to illustrate the processes of meltwater redistribution should feature grid resolutions preferably exceeding 1/12° in order to represent coastal dynamics and fjord-shelf-open ocean exchange. With more observations on the Greenland shelf hopefully becoming available in the future, we anticipate the GLORYS12 assimilation product to show similar variability as higher resolution models.
Pseudo-global-warming experiments for West Africa
Authors: Woodhams Beth , Knippertz Peter , Fink Andreas
Published: February 2023

With a rapidly growing population, West Africa is particularly vulnerable to the effects of climate change. While results from the Coupled Model Intercomparison Project (CMIP) experiments cannot agree on the sign of the end-of-century mean precipitation change over West Africa, there is consistent agreement that the most extreme precipitation events will become more intense. Indeed, an increase in the intensity of the most extreme events has already been observed in rain gauge and satellite datasets. These events are vital to understand since heavy rain can cause flooding as well as resulting property, infrastructure and crop damage, spread of disease and ultimately loss of life.In West Africa, the majority of rainfall is delivered via Mesoscale Convective Systems (MCSs). Convection associated with the land–sea breeze circulation is also significant along the Guinea Coast. It is well understood that coarse climate models are unable to accurately represent systems on the meso- and local-scale and that high-resolution ‘convection-permitting’ models are required to represent the diurnal cycle, intensity, and organisation of convection. However, such models are expensive to run, especially for the long periods required for climate simulations. One solution is to run pseudo-global-warming (PGW) simulations, where 4D (x,y,z,t) climate ‘deltas’ from CMIP models are added to high-resolution reanalysis. The resulting dataset is then used as a boundary condition for high-resolution model runs of case study events in the future climate. In this work, the ERA5 reanalysis is used as the base, and the simulations are performed using the ICOsahedral Nonhydrostatic (ICON) model.Initial results from bespoke PGW case studies for West Africa will be presented to show how the character of present-day extreme events might change if they were to occur in a future climate. In particular, the work will look at the thermodynamic and dynamic contributions to changes in intensity. Furthermore, changes in storm evolution, propagation and organisation will be analysed.
Impact of munition dumpsites on the benthic macrofauna in the western Baltic Sea
Authors: Vedenin Andrey , Kröncke Ingrid , Greinert Jens
Published: February 2023

The German waters of the North and Baltic Sea contain over 1.6 million tons of dumped munition, mostly left after the first and second World Wars. Some of the dumpsites consist of old mines and shells containing TNT, which is known to have toxic effect on marine organisms. The objective of this study was to investigate whether the structure and composition of benthic macrofauna is influenced by the munition.Two munition sites were chosen in the western Baltic Sea – Kolberger Heide (=‘KH’, Kiel Bay) and Haffkrug (=‘H’, Lübeck Bay). Samples were taken with 0.1 m2 van-Veen grab (two replicates per station), sieved through 1 mm sieve and fixed with formalin. Stations were taken at several areas near the munition dumpsites, each time arranged in two short parallel transects with ~100 m step (6-10 station per area). In addition, samples in the background areas away from munition were taken. A total of 19 stations (37 samples) were taken in ‘KH’ and 25 stations (50 samples) were taken in ‘H’. Environmental values used in this study included depth, TNT-content in bottom water layer, distance from the maximum concentration of the munition objects, latitude and longitude.A total of 118 taxa were found in ‘KH’ and 121 taxa in ‘H’. Abundance and biomass values varied among the samples greatly in both areas (from 10 to 1730 ind. 0.1 m-2 and from 0.09 to 155.37 g wet weight 0.1 m-2 respectively), although the dominant taxa were similar in all samples, including polychaetes Scoloplos armiger, Pygospio elegans, Dipolydora quadrilobate and Lagis koreni and gastropods Peringia ulvae.In ‘KH’ notably higher abundance and biomass values were observed in the control sites, while the diversity expressed in different indices (Shannon index, Rarefaction curves, Pielou’s evenness etc.) was relatively higher in the munition sites. According to the canonical correspondence analysis, species and samples were grouped along two axes, roughly corresponding to the larger TNT content and shallower depths. Linear mixed-effect model showed statistically significant values for TNT content vs. Shannon diversity index with negative linear relation.In ‘H’ the results were different with no clear abundance biomass or diversity relations to the environmental factors. However, this can be connected to a different munition distribution within the Lübeck Bay, which is more dispersed through the area, without such clear concentration area as in ‘KH’. Further possible conclusions will be discussed.
High resolution aerial sea surface temperature observations of small-scale frontal features in the open ocean
Authors: Carlson Daniel , Baschek Burkard , Burmester Henning , Hieronymi Martin , Röttgers Rüdiger
Published: February 2023

Small-scale (e.g. submesoscale and boundary layer scale) ocean features, like fronts and eddies, play a critical role in the transport and mixing of tracers. Despite recent advances, resolving such small-scale features in satellite imagery remains challenging. Accurately representing sub-grid-scale features in ocean models also remains an active area of research that should be guided by observations. Here, we present high resolution (~1 m) aerial observations of sea surface temperature that were acquired in December 2019 offshore of the island of Fogo (Cape Verde). The SST observations were obtained by a longwave infrared camera system that was operated from a Stemme powered glider. Direct georectification of open-ocean SST imagery was performed using the position and orientation data obtained from a global navigation satellite system receiver and an inertial navigation system. Georectified SST images were transferred in real-time to the R/V Meteor  to enable in situ sampling across a rapidly evolving front. The SST observations show strong convergence at the front and elevated Rossby Numbers (~O10-100), which are indicative of non-linear flows.
Turbulent energy transfer and dissipation in the terrestrial magnetosheath
Authors: Vörös Zoltan , Roberts Owen Wyn , Sorriso-Valvo Luca , Yordanova Emiliya , Narita Yasuhito , Nakamura Rumi , Plaschke Ferdinand
Published: February 2023

The terrestrial magnetosheath (MS) represents a turbulent, high-beta, compressional, sporadically Alfvenic environment which contains the shocked solar wind (SW) magnetized plasma permeated with waves, instabilities and structures of various origins. In the processes of interaction of the structured SW with the shock and the MS, the electromagnetic, kinetic and thermal energies are transported between locations,  transferred between scales, conversed between each other and finally dissipated. Similarly to the SW case the energy transfer in MS is expected to be manifested in typical scalings seen in power spectral densities of various field and plasma parameters  over the fluid (inertial-range) and kinetic ion-electron scales. However, near the sub-solar dayside MS the inertial-range turbulent cascade is usually absent, while the kinetic range scaling roughly remains the same as in the SW. Observations of short magnetic correlation lengths near the sub-solar MS also confirm the absence of large-scale magnetic fluctuations which could populate the inertial-range of scales. Without the inertial range energy cascade the kinetic range turbulence should exhibit a fast decay downstream of the shock, but it is not observed. We argue that to understand the spectral scalings in the MS the whole energy budget has to be considered including possible nonlocal energy transfer terms. By using MMS data in the MS we show that, when the inertial range is present, the turbulent energy dissipation rate can be estimated by the energy transfer rate from both the Yaglom law and from the pressure-strain interaction term. When the inertial range is absent and the Yaglom law cannot be used,  the dissipation rate can still be estimated by using the pressure-strain term.
Stalagmites' reactions to ground motion studied using modified Raspberry Shake and nodal sensors
Authors: Martin Aurélie , Lecocq Thomas , Lannoy Ari , Quinif Yves , Camelbeeck Thierry , Fagel Nathalie
Published: February 2023

Karstic zones are numerous on Earth and offer a particular field of study to evaluate the ground motion levels that occurred in the past in support of regional seismic hazard assessment. Indeed, some fine and slender candlestick stalagmites are intact and therefore indicate that a certain level of ground motion has not been exceeded since they exist. Many parameters must be considered in the behaviour of stalagmites to earthquakes such as their shape, their mechanical properties and their natural frequency. A good way to better understand and characterize the reaction of these stalagmites to earthquakes is to study their reaction to the current permanent ground motion. To do this, a study based on the measurement of ambient seismic noise is underway in the cave of Han-sur-Lesse (Ardenne, Belgium). The ambient seismic noise is measured both at the surface (above the limestone massif and in the nearest village), on the floor of the cave and on the stalagmites themselves. Different three-component seismic sensors are used in parallel: three SmartSolo IGU-16HR 3C and two Raspberry Shake 3D Personal Seismographs, one of which has been adapted to be easily attached to the stalagmites. This parallel configuration during two-week recording periods made it possible to determine the eigenfrequencies and the polarization of the associated movements of 16 stalagmites. In addition, daily and weekly variations in ambient noise and transient events are measured such as earthquakes, quarry explosions or flooding in the cave. The presence of sensors in different places over the same period also makes it possible to study the possible impact of the cave's local characteristics on these measurements.
In-phase Variations of Spring and Summer Droughts over Northeast China and Their Relationship with the North Atlantic Oscillation
Authors: Hu Yuepeng
Published: February 2023

Analyses of the standardized precipitation evaporation index (SPEI), using the season-reliant empirical orthogonal function (S-EOF) method, indicate that the second leading mode of drought over Northeast China features an in-phase variation from spring to summer. Such an in-phase change is closely connected to the persistence of geopotential height anomalies around Lake Baikal. The positive height anomalies around Lake Baikal, with an equivalent barotropic structure in the troposphere, can decrease water vapor transport into Northeast China and induce anomalous descending over Northeast China during both seasons, favoring precipitation deficit and high temperature in situ and hence resulting in the synchronous variations of spring and summer droughts. Further investigation reveals that the spring North Atlantic Oscillation (NAO) plays a notable role in the in-phase change of spring-summer droughts over Northeast China. The positive phase of spring NAO could induce spring drought over Northeast China directly through its influence on the above atmospheric circulations via a zonal wave train emanating from the North Atlantic. Meanwhile, it can also increase the soil moisture in Central Siberia by enhancing the local snow depth. The wetter soil moisture in the following summer, in turn, increases the meridional temperature gradient between the middle and high latitudes and then forces westerly anomalies around 60°N, consequently yielding positive height anomalies around Lake Baikal which favor the occurrence of summer drought over Northeast China. Therefore, the spring NAO is hypothesized to contribute to the in-phase variations of spring-summer droughts over Northeast China through the combined roles of zonal wave train and Central Siberian soil moisture.
Multi-hazard system of a high Alpine valley: construction of an event chronology from different sources
Authors: Dallons Louise , Giacona Florie , Eckert Nicolas , Frey Philippe
Published: February 2023

Mountain regions are subject to highly damaging hydrological and gravitational hazards. This exposure is due to their biophysical and societal characteristics. It is essential for a sustainable management of these risks to consider the natural risk as the result of complex interactions within the risk system, which is composed of a natural and a societal subsystem. In this way, it is possible to adopt a dynamic approach to the risk system by placing the phenomenon in an evolutionary context. We can therefore consider its trajectory according to the socio-environmental dynamics that influence it.Studying these risk systems over the long term is necessary to understand their evolution and to anticipate future ones in order to guarantee the sustainability of mountain socio-ecosystems, and requires an interdisciplinary approach between geography and history.The study of the trajectory of a multi-hazard system is being carried out in the Commune of Vallouise-Pelvoux, a high Alpine valley in the Écrins massif, France. This territory was chosen because it is subject to various risks that occur over a wide range of altitudes, its recent socio-economic development is mainly based on tourism, and it is marked by glacial recession, but also because we were aware of the availability of several sources allowing the production of event and multirisk chronologies.The first stage of the research consisted in the production of a multi-hazard event chronology over 420 years (1600-2020). This database was built from various resources. On the one hand, from existing databases produced by public services and organizations such as the French Forest Office (ONF) specifically the mountain land restoration service (RTM) or the departmental councils. On the other hand, archival research was carried out in the municipal archives of Vallouise-Pelvoux and the departmental archives of the Hautes-Alpes.After analysis of all available sources, the data collected was processed in various ways. Indeed, sources of different forms and origins requires standardization of the information to make it comparable and usable. The chronology was also subjected to a critical analysis : are the sources authentic? Reliable? What factors might influence them? Once this chronology of events in Vallouise-Pelvoux has been contextualized (changes in the natural and societal systems of the Commune), a first statistical analysis of the risks identified and the damage caused will be presented. In the future the data will be used to analyze the trajectory of the system.
Systemic design approach for climate change adaptation and enhancement of public health and wellbeing
Authors: Boskovic Stanislava , Puchol-Salort Pepe , Mijic Ana , Maksimovic Cedo
Published: February 2023

Climate change-related phenomena are putting an enormous strain on cities’ infrastructure, human livelihoods, public health and citizens well-being. This, together with the increase in urban growth and urbanization, results in an expansion of urban hazards - including water scarcity, disease transmission and consequent social issues.To address this complexity in an urban design context we introduce a Systemic Design (SyD) framework for Multifunctional Nature-based Solutions (NBS) to rethink and contribute to the planet’s health and people’s quality of life. The SyD approach focuses on context knowledge creation (environmental, climatic, social…) that includes perspectives from the point of view of multiple stakeholders, maps its key features, and analyses alternatives for exploiting different design options. Exploratory or suitability modelling supports all these steps.The examples here presented are part of the multidisciplinary project euPOLIS focused on climate change adaptation and on enhancement of public health and citizen’s well-being through the implementation of nature-based solutions (NBS). Although diversity of the size and the scale of presented case studies, the systematic baseline analysis have revealed that there are several shared conditions, such as an immediate need for improvement of existing green spaces, mitigation of direct and indirect UHI effect and refinement of maintenance systems.A mapping of the local features, and variety of specific spatial and social conditions in public spaces studied in euPOLIS’s Cities (Belgrade, Gladsaxe, Lodz and Pireas) gives synthetic prospects to better understand the potential effectiveness of Blue-Green Infrastructure (BGI) solutions (design options) in relation to their wider ecosystem and citizens’ concerns.  This leads to a systematic assessment of possible future scenarios of different scales (local, urban, regional…) and allows an examination of possible steps to better define locally specific variables, evaluation and validation of benefits to reduce existing vulnerability, and to improve community’s liveability.  The systemic design approach allows to explore the main drivers of urban development, climate change mitigation and urban resilience. In this way, it also supports decisions for further planning stages and anticipates actions for the management of the multifaceted hazards of the entire urban system.
Benthic dunite and calcite weathering as a method for ocean alkalinity enhancement
Authors: Fuhr Michael , Dale Andy W. , Wallmann Klaus , Diercks Isabel , Schmidt Mark , Kalapurakkal Habeeb Thanveer , Geilert Sonja
Published: February 2023

Abstract The natural dissolution of mafic silicate rocks (e.g. dunite) and carbonate minerals in the marine environment increases alkalinity and draws down CO2. Consequently, large-scale manual dispersal of such minerals has been proposed as a potential measure to alleviate rising atmospheric CO2 levels through ocean alkalinity enhancement (OAE). This study investigates the effects of biogeochemical processes on alkaline mineral dissolution in surface sediments in a controlled experimental environment. Dunite and calcite were added to the surface of organic rich sediments from the Baltic Sea in order to simulate mineral dissolution and OAE under oxic conditions. Eight sediment cores were incubated with ~20 cm of overlying Baltic Sea bottom water over a period of 4 months; three replicates were treated with calcite, three with dunite, and two served as unamended controls.First results indicate that the addition of the two materials directly increased benthic fluxes of alkalinity (from 1.3 to 2.5 µmol/cm2/d) and other respective weathering products such as calcium and silicate compared to the control experiments. These enhanced fluxes vanished into the strong natural benthic background after ~4 weeks. The main driver for enhanced and natural weathering is undersaturation with respect to the dissolving minerals which appears to be governed by microbial activity.As the experiment progressed, porewater pH profiles in sediment cores where the sulfur oxidizing bacteria Beggiatoa spp. were visible shifted towards profiles that were more characteristic of sediments displaying cable bacteria activity. Very low pH values (~5.6) produced by presumably cable bacteria at ~1-3 cm depth in the sediment led to strong calcium carbonate dissolution. Additionally, their metabolism provides alkalinity to the bottom water by the formation of water directly from oxygen and protons, hence without addition of corresponding cations. This microbial activity produced high pH values in the upper millimeters of the sediments (~8.5) leading to Ωcalcite values >15 that might promote CaCO3 precipitation. Enhanced dunite weathering is indicated by slightly enhanced sedimentary Si fluxes, although this proved difficult to discern from the natural background flux arising from biogenic opal dissolution.The overall natural complexity of the sediment chemistry combined with the alteration of the sediments during the incubation complicate a clear disentangling of natural and enhanced mineral weathering. Further investigation of these sedimentary systems along with field experiments will be necessary to provide estimates on the feasibility of benthic weathering as a realistic OAE and climate change mitigation measure.