bluuebunny/crossref_metadata_2025 huggingface dataset:
High-resolution topographic surveys as a quantitative method for a better understanding of soil piping processes in badlands landscapes: Valpalmas (NE Spain)
Authors: Llena Manel , Revuelto Jesús , Gómez-Gutiérrez Álvaro , López-Moreno J. Ignacio , Errea M. Paz , Alonso-González Esteban , Bernatek-Jakiel Anita , Nadal-Romero Estela
Published: February 2023

Soil piping is a land degradation process relatively common in semiarid environments which is related to rilling and gullying in badland areas. This process is a result from a complex combination of different factors as lithology (e.g., swelling clays), topography (e.g., hydraulic gradient) and climate (e.g., strong seasonal contrasts). Better understanding of piping erosion is needed since it can negatively impact land productivity and agricultural sustainability and may affect soil nutrients load and carbon cycles. Piping studies have been frequently focused on the qualitative and quantitative implications of chemical and physicochemical factors affecting the initiation of piping processes together with a qualitative analysis of the hydrological and geomorphological related processes. However, less attention has been given to the study of these processes from a quantitative point of view. High-resolution topography surveying has improved the spatial and temporal scales at which is possible to investigate the landscape through the analysis of landform attributes and the computation of topographic changes. Within this background, the aim of this work is to infer in the key geomorphic piping processes in terms of contributions to shaping the landscape by the application of multi-temporal topographic surveys through SfM-photogrammetry and TLS. To this end we analyse a 7-year dataset of seasonal and annual high-resolution topographic surveys of a badlands landscape dominated by soil piping processes in Valpalmas (NE Spain). We examine the magnitude and distribution of geomorphic processes at multiple temporal scales and its relation with landform morphometric attributes and meteorological variables. This research project was supported by the MANMOUNT (PID2019-105983RB-100/AEI/ 10.13039/501100011033) project funded by the MICINN-FEDER, the PRX21/00375 project funded by the Ministry of Universities of Spain from the “Salvador de Madariaga” programme, the Spanish Ministry of Science, Innovation and Universities (project EQC2018-004169-P) and by a grant from the Priority Research Area “Anthropocene” under the Strategic Programme Excellence Initiative at the Jagiellonian University. Manel Llena has a “Juan de la Cierva Formación” postdoctoral contract (FJC2020-043890-I/AEI/ 10.13039/501100011033) from the Spanish Ministry of Science and Innovation.
Identifying landslides from massive seismic data and machine learning: the case of the European Alps
Authors: Groult Charlotte , Hibert Clément , Malet Jean-Philippe , Provost Floriane
Published: February 2023

Recent large landslides in many parts of the World (Nuugaatsiaq, Greenland; Taan-Tyndall, US; Culluchaca, Peru) as well as the increase in the frequency of mass movements in the European Alps (e.g. collapse of the Drus, Mont Blanc Massif, France; Piz Cengalo, Switzerland) revealed the threat of such events to human activity. Seismology provides continuous recordings of landslide activity at long distances. The objective of this work is to present a method to identify and construct instrumental landslide catalogs from massive seismological data. The method is developed and applied for the period 2000-2022 at the scale of the European Alps (~ 900 x 300 km). The detection method applied to the seismological observations consists of computing the energy of the signal between 2 and 10 Hz. Then, a supervised Random Forest classifier is trained to identify the source of the event (earthquakes or landslides). To implement  the seismological detection and identification methods, we compiled a database of 65 landslides and 4515 earthquakes (of MLv > 0.1). The dataset is composed of 2221 seismological traces of landslides and 17353 traces of earthquakes. Tests of the Random Forest identification method gave us a rate of good identification of around 100% for landslides and 96% for earthquakes. Tests on continuous data of the 65 days of the reference landslide events allow finding 235 new landslides including 61 over 65 reference events.The trained model is then applied on continuous seismic data (~ 400 stations) acquired over the European Alps since 2000. To reject as many noise detections as possible, a first sorting of all detections is performed by looking at SNR ratio, number of stations involved in the detection in a small area and probability scores given by the Random Forest. The instrumental catalog is composed of ~ 183.000 possible landslides. In order to review the catalog, reject possible false detections and interpret the inventory, we developed a localization method. A first order of the localization is given by the spatial clusters of seismological stations that have detected the landslide signals. Then, to refine localizations, we compute travel times from seismological stations to all points of the area with a fast marching method and we perform the inversion by using NonLinLoc software (Lomax et al. 2000). The final landslide instrumental catalog will be presented and discussed.
Evaluation of Daily Temperature Extremes in the ECMWF ERA5 Reanalysis and Operational Weather Forecasts
Authors: Lopes Francisco , Dutra Emanuel , Boussetta Souhail
Published: February 2023

The daily maximum and minimum temperatures are among the most relevant meteorological variables in weather forecasts and climate monitoring. Their spatial and temporal evolution from synoptical to decadal scales are driven by numerous physical processes and climate feedbacks. Despite the significant improvements in weather forecasting over the last decades, forecasts of daily temperature extremes are still hampered by systematic errors. In this work we perform an integrated evaluation of the daily temperature extremes of the (i) ECMWF ERA5 reanalyses and (ii) ECMWF operational weather forecasts. The observations for the evaluation are taken from the Global Historical Climatology Network (GHCN) addressing: (i) the long-term assessment of the analysis produced by the ERA5 reanalysis, comprising a 40-year period (from 1980 to 2019); and (ii) the assessment of the ECMWF operational forecasts for a 5- year period (from 2017 to 2021). The evaluation carried out is global, however considering the GHCN station distribution and temporal availability, particular focus was given to four regions: Europe, Australia, East and West United States. The results identify a general underestimation of the daily maximum and overestimation of the daily minimum temperatures in both ERA5 analysis and operational forecasts, highlighting a known limitation of the ECMWF model in underestimating the diurnal temperature range. Our results also indicate a reduction of the errors in ERA5 when comparing the latest decade with the 1980’s, which is likely to be associated with an enhanced quality of the analysis due to a higher constrain emerging from the satellite data. The ERA5 analysis outperforms 1 day-ahead weather forecasts, which show some degree of improvement in the considered 5-year period, being associated with model upgrades. This work was developed in the framework of the CoCO2 project. CoCO2 project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 958927.
Thermal conditions and lake metabolism in the ice-covered North Aral Sea
Authors: Kirillin Georgiy , Izhitsky Alexander , Kurbaniyazov Abilgazi
Published: February 2023

Rapid desiccation of the Aral Sea, the former 4th largest lake worldwide, attracts continuous attention of researchers as an example of fast anthropogenically driven change of a large aquatic ecosystem on unprecedentedly large spatial scales. As a countermeasure preventing further desiccation, a dam was constructed in 2005 separating the northern part of the Aral Sea from the rest of the basin. The effort led to stabilization of the North Aral volume and salinity and was widely recognized as an exceptional success in large-scale water management and restoration. The “restarted” ecosystem developed within several years to a highly productive large lake. Owing to the cold arid climate, the lake is covered by ice for several months in winter while gaining significantly higher amount of solar radiation than temperate and polar ice-covered lakes. We present new results revealing characteristic features of large low-latitude brackish lake dynamics under ice cover: strong internal basin-scale waves with long periods, heating of the water column by solar light penetrating the ice cover, and arresting of vertical convective mixing by freshening of upper waters during the ice melt. The under-ice dissolved oxygen content was analyzed in terms of whole-lake metabolism and demonstrated primary production taking place during the entire ice-covered period with a strong intensification in spring months after the snow melt increased the photosynthetically active radiation level under ice.
Evidence of planetary Oxygen and Carbon ions in the outer flank of Venusmagnetosheath
Authors: Hadid Lina ,   BepiColombo - MSA team (and members from MIA, MEA and MPO-MAG teams)
Published: February 2023

On August 10, 2021, the Mercury-bound BepiColombo spacecraft flew for the second time by Venus for a Gravity-Assist Maneuver. During this second flyby of Venus, a limited number of instruments were turned on, allowing unique observations of the planet and its environment. Among these instruments, the Mass Spectrum Analyzer (MSA) that is part of the particle analyzer consortium onboard the magnetospheric orbiter (Mio) was able to acquire its first plasma composition measurements in space. As a matter of fact, during a limited time interval upon approach of the planet, substantial ion populations were recorded by MSA, with characteristic energies ranging from about 20 eV up to a few hundreds of eVs. Comparison of the measured Time-Of-Flight spectra with calibration data reveals that these populations are of planetary origin, containing both Oxygen and Carbon ions. The Oxygen observations are to some extent consistent with previous in situ measurements from mass spectrometers onboard Venus Express and Pioneer Venus Orbiter. On the other hand, the MSA data provide the first ever in situ evidences of Carbon ions in the near-Venus environment at about 6 planetary radii. We show that the abundance of C+ amounts to about ~30% of that of O+. Furthermore, Changes in the orientation of the magnetic field suggest that these planetary ions are located in the distant magnetosheath flank in the immediate vicinity of the bow-shock region.
Laser-based seismic imaging of analogue models
Authors: Smits Jasper , Beekman Fred , Willingshofer Ernst , Vasconcelos Ivan
Published: February 2023

We present and demonstrate our new application of a geophysical seismic technique to acoustically characterise and image layers with different impedance contrast in analogue models. A high-powered pulsed laser in combination with a mirror galvanometer is used to generate a powerful acoustic shockwave at any point of the surface of the analogue model. Reflections, refractions, and diffractions of the acoustic source wave, induced by internal structures inside an analogue model, produce vibrations of the top surface of a model, which are measured by laser vibrometer.Using our setup, we acquire seismic receiver gathers in less than a minute. Interpretation of the gathers allowed to identify the presence of internal reflecting and refracting material interfaces. In a series of test models, we determined the speed of both P-waves and surface waves in a multitude of brittle analogue materials. In uniform layered models we performed 1D inversion using the gathered waveform data. The results are validated by simulating the test experiments in a finite-difference solver. The novel method will be developed further, aiming to determine stress build-up in the material prior to fault formation or activity.
A framework to update 10-year-old landslide susceptibility predictions - assessing the accuracy of existing landslide susceptibility models
Authors: Lima Pedro , Steger Stefan , Petschko Helene , Goetz Jason , Bertagnoli Michael , Schweigl Joachim , Glade Thomas
Published: February 2023

Since 2014, a landslide susceptibility model is used by the Geological Survey and Spatial Planning Unit from the Regional Council of Lower Austria to guide decision-making and strategic development in the approx. 19,200 km² province. This existing map (1:25000) has been compiled by using a multi-temporal inventory composed of 12889 slides. In order to obtain the landslide susceptibility model, a generalized additive model (GAM) has been applied, using a large range of predictors. Predictions were performed on the basis of sixteen lithological units. To spatially communicate the landslide propensity, predictions are divided into three categories: low, medium, and high, based on quantiles. By design, the low landslide susceptibility covers 78% of the territory while containing 5% of the landslides. The medium susceptibility class covers 16% of the territory, including 25% of the landslides. The high susceptibility class covers 6% of the territory while containing 70% of the landslides.  Although apparently able to correctly predict landslide occurrences over these nearly ten years, this map was never quantitatively evaluated. Since late 2021, a following up review project aims to evaluate how well the existing landslide susceptibility model from 2014 was able to correctly predict the landslides occurring after its implementation. This evaluation is based on landslides that occurred after 2014. Subsequently, the landslide susceptibility will be recalculated, and potential differences between the landslide susceptibility models investigated. To assure fair comparison, an identical methodological design is applied. Changes in the spatial prediction are quantified and explored.Preliminary analysis suggests that the adequacy of the 2014 map to predict future landslides is good but highly determined by the inventories characteristics (i.e., quality and mapping method). For instance, 61% of the landslides coming from a high-quality inventory occur over highly susceptible zones. For a low-quality inventory, this percentage is observed to be rather lower (36%). However, it is also determined that, even for the landslides not occurring in the highly susceptible zone, their locations are rather close to predicted highly unstable zones. For instance, more than 80% of any landslide observations are at least 40m away from a predicted highly unstable zone. The preliminary remodeling of the landslide susceptibility (by including these new landslides) suggests for the regional scale that 88% of the territory remains with the same predicted landslide susceptibility class. However, the arrangement for the individual lithological units might substantially differ. Strategies on how to perform a comparison and updating of landslide susceptibility models are discussed. 
Sensitivity of Neoproterozoic Snowball-Earth inceptions to continental configuration, orbital geometry, and volcanism
Authors: Eberhard Julius , Bevan Oliver E. , Feulner Georg , Petri Stefan , van Hunen Jeroen , Baldini James U.L.
Published: February 2023

The Cryogenian period (720–635 million years ago) in the Neoproterozoic era featured two phases of global or near-global ice cover, termed ‘Snowball Earth’. Climate models of all kinds indicate that the inception of these phases must have occurred in the course of a self-amplifying ice–albedo feedback that forced the climate from a partially ice-covered to a Snowball state within a few years or decades. The maximum concentration of atmospheric carbon dioxide (CO2) allowing such a drastic shift is difficult to determine because it depends on the choice of model and the boundary conditions prescribed in the model. Many previous studies report values or ranges for this CO2 threshold but typically test only very few different boundary conditions. Furthermore, most studies include some kind of variability internal to the climate system but exclude variability due to volcanism. Here we present a comprehensive sensitivity study considering different scenarios for the Cryogenian continental configuration, orbital geometry, and short-term volcanic cooling effects in a consistent model framework, using the climate model of intermediate complexity CLIMBER-3α. The continental configurations comprise palaeogeography reconstructions for both Snowball-Earth periods from two different sources, as well as two idealised configurations with either uniformly dispersed continents or a single polar supercontinent. Orbital geometries are sampled as multiple different combinations of the parameters obliquity, eccentricity, and argument of perihelion. For volcanic eruptions, we differentiate between single and globally homogeneous perturbations, single and zonally resolved perturbations, and random sequences of globally homogeneous perturbations with realistic statistics. The CO2 threshold lies between 10 and 250 ppm for all simulations. While the idealized continental configurations span a difference of around 200 ppm for the threshold, the continental reconstructions differ by only 20–40 ppm. Changes in orbital geometry account for variations in the CO2 threshold by up to 32 ppm. The effects of volcanic perturbations largely depend on the orbital geometry. A very large peak reduction of net solar radiation by around –20 W/m2 can shift the CO2 threshold by the same order of magnitude as the orbital geometry. Even larger eruptions of up to –40 W/m2 may shift the threshold by up to 50 ppm. However, the smaller, more frequent eruptions mostly have much lower impacts than the changes in continental configuration and orbital geometry. Eruptions near the equator tend to, but do not always, cause larger shifts than eruptions at high latitudes. Realistic sequences of eruptions lower the long-term temperature and have a bigger effect on the CO2 threshold than single large eruptions of comparable magnitude.
Evaluating atmospheric models in the stratosphere using oceanic infrasound ambient noise.
Authors: Letournel Pierre , Listowski Constantino , Bocquet Marc , Le Pichon Alexis , Farchi Alban , Vergoz Julien , De Carlo Marine
Published: February 2023

Oceanic ambient noise (microbaroms) records are examined to retrieve information on the state of the middle atmosphere. We present an approach to compare ground-based infrasound observations with simulated infrasound detections obtained by combining a microbarom source model [1] with a semi-empirical attenuation law. Comparisons using this continuous and global infrasound source are presented for large time periods to assess performances on both seasonal and finer time scales. Infrasound detections obtained with a cross-correlation algorithm (PMCC) as well as with the new MCML (MultiChannel Maximum Likelihood) method [2] are considered. The sensitivity of simulated infrasound detections to the middle atmosphere model and to the propagation model (the transmission loss parametrisation) is evaluated. We discuss how this method may help to assess the performance of an atmospheric model in the middle atmosphere, as well as to select best members in an ensemble reanalysis. [1] De Carlo, M., Accensi, M., Ardhuin, F., and Le Pichon, A.: ARROW (AtmospheRic InfRasound by Ocean Waves): a new real-time product for global ambient noise monitoring., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7564, https://doi.org/10.5194/egusphere-egu22-7564, 2022.[2] B Poste, M Charbit, A Le Pichon, C Listowski, F Roueff, J Vergoz, The multichannel maximum-likelihood (MCML) method: a new approach for infrasound detection and wave parameter estimation, Geophysical Journal International, Volume 232, Issue 2, February 2023, Pages 1099–1112, https://doi.org/10.1093/gji/ggac377
Cenozoic Southwestern Tian Shan: Timing of Mountain Building, Intra-montane Basin Inversion, and Relation to Lithospheric Mantle Indentation
Authors: Trilsch Florian , Reuter Sanaa , Lothar Ratschbacher , Ansari Jafari Shadi , Jonckheere Raymond , Härtel Birk , Glotzbach Christoph , Wauschkuhn Bastian
Published: February 2023

Cenozoic reactivation of the Paleozoic thick-skinned fold-thrust belt of the southwestern Tian Shan has—as the Afghan-Tajik Basin inversion—been interpreted to reflect Indian mantle-lithosphere indentation underneath the Pamir. New low-temperature thermochronologic data, i.e. apatite fission-track (AFT), apatite (AHe), and zircon (ZHe) (U-Th)/He ages, reveal the exhumation history of the SW-Tajik Tian Shan along two N-S-transects. We date the reactivation and explore its temporal and spatial variations. Three domains emerged. In the Central Domain (Zeravshan-Gissar and Vashan), AFT data—aided by Raman-spectroscopic chemical-composition discrimination of detrital apatite samples and vitrinite-reflectance temperature estimates—record a ~10-13 Ma onset of shortening and >4 km exhumation. The Northern Domain, where the N-Zeravshan Fault constitutes a major Cenozoic structural divide reactivating the Paleozoic Zirabulak Suture, exhumed from <4 km, but apatite AHe ages outline a similar reactivation history as in the Central Domain. The synchronous structural reactivation implies rapid shortening propagation from the Pamir indenter across the Afghan-Tajik fold-thrust belt into and across the Tian Shan. In the Southern Domain (Gissar Batholith), ~7‒9 Ma AFT and ~4 Ma AHe ages suggest a southward shortening propagation from the northern Domains and anew thrust generation. In the hanging wall of major thrusts, ~3‒7 Ma-old AFT ages record significant and persistent exhumation but ZHe data limit it to <6 km. Most of the Southern and Central Domains cooled monotonously but temperature-time models indicate northward-decreasing reheating by syn-orogenic deposition, consistent with stratigraphic data.
Planning effective and multifunctional nature-based solutions: insights from the case-study of Malta
Authors: Balzan Mario
Published: February 2023

Nature-based solutions are increasingly promoted in regional and national policies as actions to address societal challenges and promote climate change mitigation and adaptation while leading to co-benefits to human well-being and biodiversity. However, several challenges limit the mainstreaming of nature-based solutions in decision-making. Through the presentation of case studies from the island state of Malta, we analyse the (a) use of urban ecosystem service assessment to prioritise nature-based solutions based on existing distributional patterns, (b) recent case-studies of nature-based solutions implementation, and (c) barriers and enablers to mainstreaming nature-based solutions in decision-making. We show how urban ecosystem service assessments can support greening strategies by identifying the most effective nature-based solutions that can play a redistributive role by addressing existing inequalities in ecosystem services supply within cities. Our results also indicate that while nature-based solutions were used to address multiple societal challenges, including tackling drought and heat risk, low place aesthetic value, low green infrastructure availability, and biodiversity and knowledge loss, several gaps in practice remain. We show how nature-based solutions uptake has been more strongly associated with the environmental sector, and social and economic benefits, such as green job creation, social cohesion and ownership by communities, were less often identified in the analysed case-studies. We also show how current bottlenecks, including knowledge gaps regarding the scope, cost-effectiveness and benefits arising from nature-based solutions, and limited practical experience, act as barriers to implementation while the arising public relations, adoption of interdisciplinary approaches involving multiple stakeholders, and the availability of regional guidelines were considered as key enablers. Drawing on these case-studies, we present recent collaborative work aiming at addressing some of the gaps in knowledge and practice, while engaging with communities to co-create nature-based solutions and evaluating the impacts of implementation.
Ceilometer aerosol retrieval and comparison with in-situ tower-measurements
Authors: Müller Marcus , Löhnert Ulrich , Bohn Birger
Published: February 2023

In recent years there is a growing interest in real-time aerosol profiling and in this context, the use of automated lidars and ceilometers (ALC) for aerosol remote sensing increased. Ceilometers were originally developed to measure cloud-base height automatically. Apart from this, they also provide vertically resolved backscatter information. Several algorithms have been developed to calibrate this signal and to derive aerosol concentration from it, bringing up new opportunities in air quality monitoring and boundary layer research.The quality of ALCs is often evaluated by comparing the attenuated backscatter to measurements from high-power lidars. This approach is suitable to validate the backscatter signal. However, for the validation of the aerosol concentration, a direct comparison with an in-situ, optical aerosol measurement is more significant.In this work, a comparison study was performed using the Jülich Observatory for Cloud Evolution. Data were processed and calibrated with algorithms by E-Profile (https://www.eumetnet.eu/activities/observations-programme/current-activities/e-profile/alc-network/). The aerosol retrieval was performed using a Klett inversion algorithm. Close to the JOYCE site a 120 m meteorological tower is located. This tower was used as a platform for the in-situ aerosol measurement, where an optical particle sizer was mounted 100 m above the ceilometer position.We will show the setup and data processing of the in-situ measurements as well as an approach how ceilometer raw data can be processed, calibrated and used to retrieve aerosol concentration. First results of the comparison will be presented to evaluate the quality of ALC aerosol-measurement.
Effect of aerosols on the properties of low-level liquid clouds over the Southern Great Plains, USA
Authors: Taneja Kanika , Kokkola Harri , Romakkaniemi Sami , Arola Antti , Chellappan Seethala , Mielonen Tero
Published: February 2023

One of the largest uncertainties in estimating the anthropogenic radiative forcing is related to the impact of atmospheric aerosols on cloud properties. This uncertainty originates mainly from the complicated nature of aerosol-cloud interaction as it is much stronger and more difficult to observe than the aerosol-radiation interaction. The estimates of radiative forcing due to changes in cloud properties vary significantly between different global climate models, highlighting the need for constraining this forcing by using observations. Moreover, it is challenging to determine the impact of aerosols on clouds from satellite observations only. In this study, we aim to improve that by combining the in-situ observations with satellite retrievals, in order to reduce uncertainties in the anthropogenic impact on clouds and the climate. The study is performed for the low-level liquid clouds over the Southern Great Plains (SGP), Oklahoma. The in-situ data on particle number concentration, large enough to act as cloud condensation nuclei (CCN), with diameter larger than 100 nm (N100) were collected for a 5-year period from the Atmospheric Radiation Measurement (ARM) observatory at SGP site. In this analysis, the level-2 collection-6 MODIS cloud property dataset (MYD06_L2) with a 1x1 km resolution was used, where only liquid, single-layer clouds with a cloud top warmer than 268 K were included. It was observed that both CER and COT increased with increasing CWP. However, at a same level of CWP, the CER was smaller, and COT was larger at high N100 concentrations, as compared to the lower N100 concentrations. This result is consistent with the hypothesis of enhanced aerosol load increasing the number concentration of CCN, which in turn leads to smaller cloud droplets.
Computer simulation investigation of the adsorption of acetamide under atmospheric and interstellar conditions
Authors: Jedlovszky Pal , Balbisi Mirjam , Horvath Reka , Szori Milan
Published: February 2023

Acetamide is not only released into the atmosphere from natural sources, but its large-scale industrial use also results in its atmospheric emission. The main atmospheric sink of acetamide is its oxidation, however, other atmospheric fates are also plausible. In wet deposition, acetamide can be captured by ice grains through adsorption. Thus, we investigated the adsorption of acetamide at the surface of crystalline (Ih) and low density amorphous (LDA) ices by performing a set of grand canonical Monte Carlo simulations at the tropospheric temperature of 200 K. Besides calculating the adsorption isotherms, we also characterised the energetics of the adsorption and the orientational preferences of the first layer molecules. We demonstrated that at low enough surface concentrations, the adsorbed acetamide molecules prefer to lay parallel with the ice surface. With increasing surface coverage, acetamide molecules preferentially stay perpendicular to the surface, pointing by the CH3 group straight away from the ice phase, typically forming 2 H-bonds with each other and 2 with the surface waters. Finally, after the appearance of outer layer acetamide molecules, first layer molecules prefer to form 3 H-bonds with their acetamide neighbours and only 1 with the surface waters.As acetamide has been detected in a relatively large amount in space as well, we extended our study by performing grand canonical Monte Carlo simulations at 50 and 100 K on LDA ice, which are more characteristic of typical domains of the interstellar medium. We found that the relative importance of the acetamide–acetamide H-bonds with respect to the acetamide–water ones increases with decreasing temperature. As a result of it, the saturated monolayer, which is stable in a broad range of chemical potentials at 200 K, shrinks with decreasing temperature, and, eventually, vanishes at 50 K, while multilayer adsorption becomes more and more pronounced at the lower temperatures. Furthermore, our results suggest that non-negligible acetamide adsorption might occur on LDA surfaces at low enough temperature (i.e., 50 K and below), thus, the interstellar formation of peptide chains through acetamide molecules might well be a plausible process in the cold domains of the interstellar medium; however, it is rather unlikely in the higher temperature domains.
Immature transform plate boundaries in the Northeast Pacific: Constraints from ocean bottom seismology
Authors: Ren Yu , Lange Dietrich , Grevemeyer Ingo
Published: February 2023

Plate tectonics defines oceanic transform faults as long-lived tectonics features. In the Pacific Ocean their traces, called fracture zones, can easily be identified as several thousands of kilometer-long features in bathymetric and gravity field data. However, today none of the fracture zones in the North Pacific are directly linked to any mid-ocean ridge-transform fault. This feature is related to the subduction of the Farallon spreading center and a major change in the direction of plate motion several millions of years ago. Consequently, ridge segmentation is adjusting to a new tectonic framework. The Blanco transform fault system (BTFS) in the northwest off the coast of Oregon is one of the newly evolving transform faults. It is highly segmented and shows strong similarities with other segmented oceanic transform systems, such as the Siqueiros in the East Pacific Rise, which developed from a pre-existing transform fault subjected to a series of extensional events due to a documented change in spreading direction. However, plate tectonic reconstructions suggested that the BTFS developed from at least two large ridge offsets rather than a single transform fault, emerging from a series of ridge propagation events after the plate reorientation at ~5 Ma.We used one year of ocean-bottom-seismometer data from the Blanco Transform OBS Experiment (2012-2013) and high-resolution multibeam bathymetry, aeromagnetic, and gravity datasets to study the seismotectonic behavior and tectonic evolution of the BTFS. Interestingly, all available datasets provide no evidence for the existence of either transform faults or fracture zones around the BTFS before 2 Ma, supporting that there were no pre-existing transform faults before the initiation of the BTFS. Therefore, we suggest the BTFS developed from two broad transfer zones instead of pre-existing transform faults. We present seismicity and focal mechanisms for stronger manually-picked events.  Furthermore, the seismic data were picked with a phase picker learned with a large OBS training dataset. The resulting seismicity of ~8,000 events reveals the present-day deformation of the fault system with very high spatial resolution, and supports substantial along-strike variations, indicating different slip modes in the eastern and western BTFS. Seismic slip vectors suggest that the eastern BTFS is a mature transform fault system accommodating the plate motion. At the same time, the western BTFS is immature as its re-organization is still active. The BTFS acts as a natural laboratory to yield processes governing the development of transform faults away from continental rift zones.
Sugar like compounds in PM2.5 at three rural background sites in Central Europe
Authors: Schwarz Jaroslav , Lhotka Radek , Pokorná Petra , Vodička Petr , Zíková Naděžda , Ondráček Jakub , Arora Shubi , Poulain Laurent , Herrmann Hartmut , Ždímal Vladimír
Published: February 2023

Sugar like substances are usually small but important part of organic aerosol being often tracers for individual aerosol sources. Twelve hours samples (day and night) collected during winter and summer campaigns at three Central European rural background sites were utilized to characterize PM2.5 aerosol using complex set of analytical methods. Here we report concentrations of sugars, sugar like alcohols and sugar anhydrides.PM2.5 samplings were performed during February–March and July–August 2021 at three sites, National Atmospheric Observatory Košetice – CZ (NAOK, N 49°35′, E 15°05′; 534 m a.s.l.), Frýdlant – CZ (N 50°94′, E 15°07′; 366 m a.s.l.) and Melpitz –DE (N 51°32', E 12°56'; 86 m a.s.l.). Each site was equipped with high volume Digitel sampler using sampling flow rate 500 l/min. Cut parts of the filter were extracted with ultrapure water and the extracts were analysed using HPAE-PAD analysis and Thermo Scientific 5000+ system for sugar-like substances using a method based on Iinuma et al. 2009.The concentrations of sugar like substances were dominated by levoglucosan in winter at all sites, with 0.32±0.29 µg/m3 at Košetice, 0.21±0.13 µg/m3 at Frýdlant, and 0.15±0.13 µg/m3 at Melpitz. Mannosan/levoglucosan median ratio was the highest at Košetice (0.23) and lowest at Frýdlant (0.18).The summer concentrations of sugar like substances were more evenly distributed in several major substances with concentrations one order lower in comparison to concentrations of levoglucosan in winter. The concentrations of individual sugars, sugar alcohols and sugar anhydrides were relatively evenly distributed, but some differences between the sites were found. The average sums of sugars were the highest of all categories at all sites, but while the sugar alcohols were the second highest in Melpitz, the content of sugar anhydrides was at the second place at Frýdlant and Košetice in summer. Acknowledgements:This work was supported within a German-Czech cooperation in the TRACE project funded by the GACR under grant 20-08304J and by DFG under grant 431895563, also by the MEYS of the Czech Republic under grants ACTRIS-CZ LM2018122 and ACTRIS-CZ RI (CZ.02.1 .01 / 0.0 / 0.0 / 16_013 / 0001315), and European Union's Horizon 2020 research and innovation program ACTRIS IMP (871115). References:Iinuma, G. Engling, H. Puxbaum, H. Herrmann, A highly resolved anion-exchange chromatographic method for determination of saccharidic tracers for biomass combustion and primary bio-particles in atmospheric aerosol, Atmos. Environ., 43 (2009), pp. 1367-1371, 10.1016/j.atmosenv.2008.11.020
Influence of the Atlantic Multidecadal Variability and of Soil Moisture on Extreme Heatwaves in Europe
Authors: Mascolo Valeria , Le Priol Clément , d'Andrea Fabio , Bouchet Freddy
Published: February 2023

Nowadays heat waves are a growing issue, causing detrimental effects on society, people’s health and environment in several parts of the world. Slow drivers such as spring soil moisture and sea surface temperature are known to impact the probability of occurrence of heatwaves in many areas of the globe. However, their influence remains still little understood and studied. Even fewer has been said on the cross effect and relative impact of both factors. Our work aims at analysing and comparing the effects of spring soil moisture deficit in Europe and sea surface temperature decadal variability in the North Atlantic (AMV) on the occurrence of typical and more extreme European heat waves. To do that, we use the outputs from three climate models, namely IPSL-CM6A-LR, EC-Earth3 and CNRM-CM6-1, in which North Atlantic sea surface temperatures are nudged to the observed AMV anomalies.At a methodological level, previous studies mainly focused on typical heat waves. Our work goes beyond that and proposes a new methodology to study events with larger return times. By introducing return time maps we can study rare heatwaves with return time from 10 to 50 years. We find that the temperature and duration of typical and extreme heatwaves are influenced by the AMV and soil moisture. In general, the changes induced by typical AMV or soil moisture anomalies are of comparable amplitude. In many areas of Europe, the influence of AMV and soil moisture over duration or temperature of extreme heatwaves increases when the return time is longer and is statistically significant even for return times of 50 years. In general, the three models give consistent results. With positive AMV phase or low soil moisture, the temperature and duration of extreme heatwaves are changed according to regional patterns. As might be expected, positive AMV phase or low soil moisture often induce hotter and longer typical and extreme heatwaves. However, counter-intuitively, they also induce cooler and shorter heatwaves over part of Northern-Eastern Europe. For more extreme events, the impact of the AMV and soil moisture increases, according to rather similar regional patterns. However, the regions with decreased temperature or duration impact extend in size.In this work, we have improved the study of extreme heat waves and better understood their slow drivers. Studying those drivers is important to enhance heat wave predictability. To move further in this direction, we need to improve the statistics of the events. In this context, developing and using new tools such as rare event simulations might be the right path to follow.
The role of stratified turbulence in the cold summer mesopause region
Authors: Avsarkisov Victor , Conte Federico
Published: February 2023

The primary physical mechanism behind the formation of the summer mesopause at middle and high latitudes is related to atmospheric gravity waves. An insight into this extreme thermal phenomenon can be gained from investigating the mesoscale energy spectrum. In this work, we decompose the frequency spectrum into divergent and rotational parts and find that their energy contributions are equipartitioned at high frequencies. This mesoscale energy equipartition indicates the effect of stratified turbulence. Analysis of the power spectra of observed and simulated horizontal winds at middle latitudes reveals the role of stratified turbulence in the formation of the summer mesopause region.
Significant parameters of a landslide dam inventory from the stability assessment aspect - data analysis based on the 'part of the Eastern Alps' data inventory
Authors: Shafieiganjeh Roshanak , Ostermann Marc , Schneider-Muntau Barbara , Gems Bernhard
Published: February 2023

Landslide dams are counted as one of the most destructive mountain hazards. They pose flood hazards downstream and damming effects upstream. Assessing their stability requires either a detailed case study or relying on geomorphic indices. A case-study project, while being accurate, is time-consuming and cannot be implemented during emergencies. Therefore, geomorphic indices which are calibrated based on the landslide dam inventories facilitate the stability assessment of these dams.Landslide dam inventories generally include qualitative and quantitative parameters of geographical location, landslide, dam, lake, and upstream catchment. In the current research, a comparison is made on the applicability of the existing geomorphic indices on a developed data inventory of Western Austria, Bavaria, and Northern Italy. The comparison indicates that the geometrical parameters can solely or in combination with each other stand as resisting and driving forces and that the stability assessment based on these parameters is reliable. According to the results, the volume and height of the dam are the most representative parameters of the dam's stability. However, the catchment characteristics such as area, slope, and ruggedness act as the determining destructive force. To evaluate the reliability of the methods used in the calculation or estimation of the geometric parameters, a statistical assessment is conducted based on the data from other published inventories. A wide range of variations in the mean value of the landslide and dam volume indicates the results' dependency on the study areas' geomorphological characteristics. On the other hand, the dam height of the current dataset, the datasets of Japan, New Zealand, and a worldwide database varies in only a 15 m range indicating a close estimation in different geographical regions. This emphasizes the necessity of the existence of a determining procedure for the estimation of such representative parameters in the landslide dam inventories.
Heat hazard and risk assessment in urban areas. Case study of Bucharest (Romania)
Authors: Cheval Sorin , Dumitrescu Alexandru , Micu Dana , Onțel Irina , Paraschiv Monica-Gabriela , Simion Gabriel
Published: February 2023

Climate and climate-related hazards are growing threats to our cities, as a result of the twin challenges derived from the warming climate and urban expansion. Accountable development strategies must take into consideration the safety of the urban population, including its vulnerability and exposure to different hazards. The evaluation of risks related to heat hazards is a priority for urban municipalities, especially in big cities where the urban heat island intensity is significant. For example, the urban perimeter of Bucharest (Romania) is 2 - 3°C warmer than the 5 km buffer of the rural neighborhood, as an average of the land surface temperature (LST) over the summer months.This research explores the risk associated with the heat hazard occurring over Bucharest due to vulnerabilities derived from different urban elements, such as population, land cover-land use, local climate zones, and characteristics of the buildings. The analysis covers the period 2013-2022, and the outputs are delivered at 100-m spatial resolution. The heat hazards were derived from LST retrieved from high-resolution imagery (i.e. Landsat 8) data using emissivity estimation, and the urban risk was calculated based on several variables related to demographics and built environment, considering their influence on the vulnerability to heat hazard. The Heat Hazard-Risk was computed using a risk matrix approach, as a product between the heat hazard and vulnerability, and the results inform the level of Census Administrative Units (CAU).The results show that the heat hazard is more frequent during the warm season, and especially in June-July-August, when the average daily LST exceeds 40°C over the largest part of the city. The land cover characteristics and the LCZ have a significant influence on the LST values and generate adverse impacts on health, economic activities, and the environment.As regards the demographic profile, this study examines the consequent risk derived from (a) population size (i.e. number of inhabitants and density), (b) age (i.e. younger and older people), and (c) density of people in the same dwelling.This study has been partly funded by the project Synergies between Urban Heat Island and Heat Wave Risks in Romania: Climate Change Challenges and Adaptation Options (SynUHI) PN-III-P4-PCE-2021-1695.
Developing storylines for unprecedented extreme events using ensemble boosting
Authors: Bloin-Wibe Luna , Fischer Erich , Knutti Reto
Published: February 2023

Recent extreme temperature and precipitation events such as the dry and heat events in summer 2022 in Europe and China, the New Year’s warm spell 2022/23 across Europe, the 2021 heavy rainfall extremes in northwestern Germany, Belgium and the Netherlands and the 2021 Pacific Northwest heatwave broke previous observed record levels by large margins. The probability of such unprecedented record-shattering extremes increases with the rapid rate of warming. Thus, there is a crucial need for analyzing the underlying processes leading to these events and quantifying potential intensities of events possible in the coming decades.Here, we evaluate how ensemble boosting (Gessner et al. 2021 and Gessner et al. 2022) can help assess the tail of climate distributions and generate climate model-based storylines more resource-efficiently. In ensemble boosting the most extreme simulated events in an intermediate-size initial condition ensembles are re-initialized in targeted experiments in order to efficiently sample very extreme states of the model climatology. Here, we evaluate different ensemble design choices including lead time, ensemble size and potential iteration choices to most efficiently allocate computational resources to simulate events of very extreme intensity.The resulting boosted events are analyzed through a storyline approach, thus helping to interpret the underlying mechanisms of each physically consistent unfolding extreme event and its consequences. The Pacific Northwest heatwave in June 2021 will be used as a starting point; but ensemble boosting and storylines can be powerful tools for understanding extremes beyond heat. We further discuss how ensemble boosting can also be applied to compound extremes and future climate scenarios.
Cascade effects of triggered earthquakes of cascade dams: Taking Xiluodu and Xiangjiaba reservoirs as examples
Authors: Yin GuangYao , Zhang Huai , Shi YaoLin
Published: February 2023

This study investigates the perturbations of the surrounding stress field caused by the cascade effect of Xiluodu and Xiangjiaba reservoirs after impoundment and a three-dimensional pore-elastic coupling model of the impoundment of cascade reservoirs are established. The finite element method calculates the pore pressure field, elastic stress field, and variation of Coulomb stress on local faults. The results show that: 1) the spatial distribution of the earthquake cluster is obviously consistent with the area where the pore pressure increases; 2) The ΔCFS at the epicenters of the April 2014 Yongshan M_L5.1 earthquake and the August 2014 Yongshan M_L5.2 earthquake imparted by the reservoirs are: 0.67kPa and 10.87kPa, respectively, indicating that impoundment promotes these two earthquakes at different levels, and the latter is more significant; 3) The elastic stress field change imparted by the impoundment of Xiluodu reservoir has an impact on the Xiangjiaba Reservoir in the early stage. However, the earthquakes between two reservoirs are possibly triggered by the latter. The Xiangjiaba reservoir increases the pore pressure in its upstream part by 1.0 kPa; 4) the impoundment of the reservoirs increases the seismic risk of the southern section of the Yanfeng fault and the middle section of the Lianfeng fault, while the Manao fault is less affected.