bluuebunny/crossref_metadata_2025 huggingface dataset:
3D Venusian Ionosphere model: Venus PCM
Authors: Martinez Antoine , Chaufray Jean-Yves , Lebonnois Sébastien
Published: February 2023

For twenty years, a Planetary Climate Model (PCM) has been developed for the Venus atmosphere at “Institut Pierre-Simon Laplace” (IPSL), in collaboration between LMD and LATMOS, from the surface up to 250 km altitude (Lebonnois et al., 2010; 2016; Martinez et al., 2023). Recently, the Venus PCM (former IPSL Venus GCM) has been updated with the addition of photoionization and ion-neutral chemistry to simulate the Venusian ionosphere at altitudes where the photoequilibrium assumption is valid (below 180-200 km at dayside), based on the Martian ionospheric model described in González-Galindo et al., 2013.By simulating the ionosphere and comparing the results with observations from spacecraft missions, we have been able to better understand the processes at work in the Venusian ionosphere. Here, we will focus on the main ion species (O+, CO2+, O2+, H+, CO+) and on the modeling of the Venusian ionosphere by Venus PCM through the comparison of the ionosphere composition with Pioneer Venus observation (PV-OIMS, PV-OETP). We also explore the effects of the addition of ambipolar diffusion on the vertical density profile of the main ions, based on the work of Chaufray et al., 2014 for the Martian ionosphere.References:Chaufray, J.-Y., Gonzalez-Galindo, F., Forget, F., Lopez-Valverde, M., Leblanc, F., Modolo, R., Hess, S., Yagi, M., Blelly, P.-L., and Witasse, O. (2014), Three-dimensional Martian ionosphere model: II. Effect of transport processes due to pressure gradients, J. Geophys. Res. Planets, 119, 1614– 1636, doi:10.1002/2013JE004551.
Lebonnois, S., Hourdin, F., Eymet, V., Crespin, A., Fournier, R., Forget, F., 2010. Superrotation of Venus’ atmosphere analyzed with a full general circulation model. J. Geophys. Res. (Planets) 115, 6006. https://doi.org/10.1029/2009JE003458.
Lebonnois, S., Sugimoto, N., Gilli, G., 2016. Wave analysis in the atmosphere of Venus below 100-km altitude, simulated by the LMD Venus GCM. Icarus 278, 38–51. https://doi.org/10.1016/j.icarus.2016.06.004.
González-Galindo, F., J.-Y. Chaufray, M. A. López-Valverde, G. Gilli, F. Forget, F. Leblanc, R. Modolo, S. Hess, and M. Yagi (2013), Three-dimensional Martian ionosphere model: I. The photochemical ionosphere below 180 km, J. Geophys. Res. Planets, 118, 2105–2123, doi:10.1002/jgre.20150.
Martinez, A., Lebonnois, S., Millour, E., Pierron, T., Moisan, E., Gilli, G., Lefèvre, F., Exploring the variability of the Venusian thermosphere with the IPSL Venus GCM, Icarus, 2023, 115272, 0019-1035, https://doi.org/10.1016/j.icarus.2022.115272
OpenMRG: Open data from Microwave links, Radar, and Gauges for rainfall quantification in Gothenburg, Sweden
Authors: van de Beek Remco (C.Z.) , Andersson Jafet , Olsson Jonas , Hansryd Jonas
Published: February 2023

In a changing climate accurate measurements and near-real time rainfall monitoring are essential for sustainable societies. Commercial microwave links (CMLs) offer a great alternative, or addition, to traditional sensors, like rain gauges and radar. While CMLs are a great source of opportunistic sensors the data from CMLs are usually limited by their accessibility for both research and actual implementation. To help in gaining better access and research into CML-derived rainfall we present a dataset at 10 second resolution with true coordinates for 364 bi-directional CMLs gathered during a pilot study in Gothenburg, Sweden over a three-month period (June-August 2015). These data are complemented by additional data from 11 high-resolution rain gauges (ten 1 min and one 15 min) and radar data (5 min and 2 km resolution) from the Swedish operational weather radar composite over the Gothenburg area.Analysis of the data show that data collection is very complete, with 99.99% of the CMLs, 100% rain gauges and 99.6% of the radar data available. The gauge data shows that around 260mm rainfall was measured during this period with 6% precipitation during 15-minute intervals. At the Torslanda gauge on 28 July 2015 one the of the most intense events was observed during the three-month period with a peak intensity of 1.1 mm min−1. The CML data reflect this event well and show a drop of around 27 dB during the peak intensity. Radar data also showed a good distribution of the reflectivity of the precipitation with some measurements above 40 dBZ, which is commonly taken as an indication of convective precipitation. Some low intensity clutter was also found, mostly around -15 dBZ.The data are accessible at https://doi.org/10.5281/zenodo.7107689 (Andersson et al., 2022). The sharing of these Open high-resolution data of Microwave links, radar and gauges (OpenMRG) should enable further research in microwave-link based environmental monitoring. In the longer term we hope that this dataset will also contribute to easier access of CML data and help in the development of the merging of multi-sensor products.
The devastating 2022 M6.2 Afghanistan earthquake: challenges, processes and implications
Authors: Kufner Sofia-Katerina , Bie Lidong , Gao Ya-Jian , Lindner Mike , Waizy Hamidullah , Kakar Najibullah , Rietbrock Andreas
Published: February 2023

On June 21th, a Mw6.2 earthquake struck the Afghan-Pakistan-border-region, an area dominated by partitioned deformation related to the India-Asia collision. Despite its moderate size, 1150 deaths were reported, making the event the deadliest earthquake of 2022 so far. We investigate the event’s rupture processes, aiming to understand what made it that fatal. Our InSAR-constrained slip model and regional moment-tensor inversion reveal a sinistral rupture with maximum slip of 1.8 m at 5 km depth on a N20°E striking, sub-vertical fault. Field observations confirm fault location and slip-sense. Based on our analysis and a global comparison, we suggest that not only external factors (e.g. time of the event and building stock) but also fault-specific factors made the event excessively destructive. Surface rupture was favored by the local rock anisotropy (foliation), coinciding with the fault strike. The distribution of Peak Ground Velocity was governed by the sub-vertical fault. The maximum slip was large compared to other events globally and might have resulted in peak-frequencies coinciding with the resonance-frequency of the local one-story buildings. More generally, our study demonstrates the devastating impact of moderate earthquakes, being small enough to be accommodated by many tectonic structures but large enough to cause significant damage.
Analysis of “Tasman” poplar’s (Populus deltoides x Populus nigra) root systems for the quantification of bio-engineering services in New Zealand pastoral hill country.
Authors: Ngo Ha My , van Zadelhoff Feiko Bernard , Gasparini Ivo , Plaschy Julien , Flepp Gianluca , Dorren Luuk , Phillips Chris , Giadrossich Filippo , Schwarz Massimiliano
Published: February 2023

Poplar (Populus sp.) is an important species for preventing shallow, rainfall-triggered landslides and hydraulic bank erosion in New Zealand. However, quantifying the spatial root distribution pattern and reinforcement remains challenging. This study aimed to find the Root Bundle Model with the Weibull survival function (RBMw), a root distribution model (RDM), and a root reinforcement model for the implementation in models such as BankforMAP and SlideforMAP. Our study was conducted within a 26-year-old “Tasman” poplar stand at Ballantrae Hill Country Research Station in the North Island of NZ. We measured root distribution at distances of 1.5, 2.5, 3.5, and 4.5 m from the stem of four poplar trees whose diameters ranged from 0.41 to 0.56 m and from eleven soil profiles along a transect located in a sparse to a densely planted poplar stand. This created a unique database of root distribution. 124 laboratory tensile tests and 66 field pullout tests on roots with diameters up to 0.04 m were carried out. The root distribution model well predicted spatial root partition in trenches of single tree root systems with R2 = 0.78 and in the transect with R2 = 0.85. The model tends to overestimate root distribution when planting density was higher than 200 stems per hectare. The maximum lateral root reinforcement model tends to underestimate forces in single tree root systems with R2 = 0.64, but it well performs along the transect within the stand with different planting densities. The basal root reinforcement model performed well in predicting its vertical distribution as a function of soil depth. In conclusion, our study provided a detailed dataset for the quantification of root distribution and reinforcement of poplars on a hillslope for the purpose of increasing slope stability and mitigating hydraulic bank erosion. The implementation of these data in models for the simulation of shallow landslides and hydraulic bank erosion is fundamental for the identification of hazardous zones and the prioritization of bio-engineering measures in NZ catchments. Moreover, the results are used to formulate a general guideline for the planning of bio-engineering measures considering the temporal dynamics of poplar’s growth and their effectiveness in sediment and erosion control.
era5cli: from a utility script to a reusable software package
Authors: Schilperoort Bart , Kalverla Peter , Vreede Barbara , Verhoeven Stefan , Alidoost Fakhereh , Liu Yang , Drost Niels , Aerts Jerom , Hut Rolf
Published: February 2023

The ERA5 meteorological reanalysis dataset, from the European Centre for Medium-Range Weather Forecasts (ECMWF), is widely used in areas such as meteorology, hydrology and land-surface modelling. The Copernicus Climate Data Store (CDS) offers two options for accessing the data: a web interface and a Python API. However, automated downloading of the data requires advanced knowledge of Python, and can prove challenging to people less familiar with programming.Many climate scientists have their own Python scripts to download data from the CDS, all responsible for their own creation and maintenance. A quick search for Python scripts that call the CDS API on GitHub yields 1802 results, and this is not even counting scripts stored privately. However, these are by and large not reusable. A few years ago we created era5cli, as a byproduct of a project we were working on, to try to break this pattern of single-use scripts. era5cli enables automated downloading of ERA5 data using a single command.It is inefficient that everyone writes their own copy of the same, or at least similar code. That why we asked ourselves whether era5cli is still filling a niche and if so, what we could do to make it easier to re-use for others. In this presentation we give an overview of our recent efforts into turning era5cli from a utility script into a reusable software package.Despite the relatively small size of era5cli, around 1000 lines of Python code and comments, maintenance is not trivial. Changes are occasionally made to ERA5 and the CDS, and new Python versions are released while old ones are deprecated. Users of era5cli have helped here by submitting fixes to issues they have found in a Github pull request, but still require guidance and/or approval of administrators. By reducing the maintenance load of era5cli, through targeted streamlining of the code and a clean-up of the repository, as well as adding to the developer instructions in the documentation, we lower the threshold for community contributions and successful future maintenance. With this, we aim to make era5cli future-proof.era5cli can be installed using Python’s pip, as well as using conda/mamba (conda install era5cli -c conda-forge). The source code for era5cli is available on https://github.com/eWaterCycle/era5cli, and the documentation can be found on https://era5cli.readthedocs.io/.
Decadal prediction along the Western Irish Coast
Authors: O'Beirne Catherine , McCarthy Gerard , Düsterhus André
Published: February 2023

Over the last decade there have been vast improvements in the field of global decadal climate prediction; however, on a regional scale there is still limited confidence. Previous studies with the Max Plank Institute Earth System Model (MPI-ESM) have demonstrated that it can replicate water properties on a regional scale in the North Sea and Barents Sea.In this study we investigate the prediction skill at depth along the Western Irish Coast using the MPI-ESM. For this we compare Hindcast simulations with Historical simulations. The employed Hindcast simulations consists of an ensemble mean of 16 members over the time frame 1961-2008 with a 2-to-5-year lead time. The Historical simulations over the same time frame also consist of an ensemble mean of 16 members.For this contribution we investigate further the MPI-ESM predictability at depth for temperature and salinity along three transects that influence the Western Irish Coast at the Extended Ellet Line northwest, Galway Transect west, and Goban Spur southwest. A lead time analysis determines the improvement of prediction skill by initialisation. We discuss potential applications for this work in areas such as fisheries, coastal security, and marine leisure, for Ireland and its surrounding seas.
Stochastic description of mean flow hydrograph shape for flood modeling and river engineering design purposes
Authors: Calvani Giulio , Perona Paolo
Published: February 2023

The engineering design of hydraulic infrastructures in either urban or rural environments requires flow hydrograph scenarios to be tested in numerical models. Whilst peak flow discharge is calculated according to a return period analysis of historical data,  the definition of the corresponding hydrograph duration and shape is not unique. The first one is typically considered either equal to the concentration time of the catchment or dependent on rainfall event intensity and duration. The shape of the hydrograph is then defined as a rectangle (e.g., constant flow discharge) or other simple shapes (e.g., triangle) according to empirical rules. In this work, we propose the definition of an average hydrograph shape based on the stochastic analysis of the Compound Poisson Process, which is usually considered as a proxy model for hydrological data in several applications. Once the peak flow discharge value is derived by means of the Peak Over Threshold analysis and a baseflow value is set, we calculate the duration of both the raising and the falling limbs of the hydrograph based on the concept of mean first passage time across thresholds for non-Markovian processes. As this technique considers the ensemble of the infinite possible stochastic trajectories reaching the threshold, it then returns a more comprehensive description of the possible mean shape of the hydrograph. Such a shape can also be approximated by using relationships already available in the literature (e.g., the Yevdjevich function). In definitive, the proposed approach provides more reliable results when the hydraulic processes being modelled (e.g., flow erosion) require that not only the peak but also the shape and the hydrograph duration are important for verification and design purposes.
Delineating giant Antarctic icebergs with Deep Learning
Authors: Braakmann-Folgmann Anne , Shepherd Andrew , Hogg David , Redmond Ella
Published: February 2023

Icebergs account for half of all ice loss from Antarctica. Their melting affects the surrounding ocean properties through the intrusion of cold, fresh meltwater and the release of terrigenious nutrients. This in turn influences the local ocean circulation, sea ice formation and biological production. To locate and quantify the fresh water flux from Antarctic icebergs, we need to track them and monitor changes in their area and thickness. While the locations of large icebergs are tracked operationally by manual inspection, delineation of iceberg extent requires detailed analysis – either also manually or through automated segmentation of high resolution satellite imagery.In this study, we apply three machine learning techniques to 191 Sentinel-1 images between 2014 and 2020 and assess their skill to segment seven giant Antarctic icebergs between 54 and 1052 km2 in size. Most previous studies to detect icebergs have focused on smaller bergs. In contrast, we aim to segment selected giant icebergs with the goal to automate the calculation of their changing area, volume, and freshwater input. Two of our techniques are standard segmentation techniques (k-means and Otsu thresholding) and the third one is a deep neural network (U-net). It is the first study to apply a deep learning algorithm to iceberg detection.We analyse the strengths and weaknesses of the different machine learning approaches across a range of challenging environmental conditions: These include scenes where the iceberg is surrounded by deformed sea ice, when other big bergs are present and when berg fragments are close to the main iceberg. We also cover cases when the iceberg drifts close to the coast and summer images with surface thawing conditions, which invert the backscatter contrast between iceberg and ocean.
Influence of fault rocks’ mineralogy on fault behaviour: implications from the Palu-Hazar Lake section of the East Anatolian Fault (Elazığ, Türkiye)
Authors: Çakır İrem , Zabcı Cengiz , Köküm Mehmet , Ünal Ercan Hatice , Kıray Havva Neslihan , Yazıcı Müge , Basmenji Mehran , Yağcı Özlem , Şahinoğlu N. Beste , Doğan Uğur , Ergintav Semih
Published: February 2023

The multi-disciplinary studies yield a more complicated picture on seismic cycles, especially with the increasing evidence on creeping, slow slip events, tremors and repeating earthquakes. Recent observations support triggering of large earthquakes even by small or slow earthquakes and creeping of different portions of the fault. The Palu-Hazar Lake section of the East Anatolian Fault (EAF) is an example place of such kind of behaviour, where the 24 January Mw 6.8 Sivrice Earthquake was nucleated along the neighbouring segments. This sinistral strike-slip fault forms the eastern boundary of the Anatolian Scholle between Karlıova (Bingöl) in the northeast and Türkoğlu (Kahramanmaraş) in the southwest within the complex tectonic frame of the Eastern Mediterranean.In this study, we aim to correlate any potential influence of bedrock lithology on this creeping section of the EAF. First, we revised the active fault and geological maps by using the multi spectral satellite images (e.g., Landsat 8 OLI) and high-resolution digital surface models (~0.65 m ground pixel resolution). Then, we determined potential exposures along the EAF and made systematic sampling both from cohesive and incohesive fault rock exposures within our study region. Collected samples are prepared for X-ray diffraction (XRD) measurements, especially for the determination of the fault clay types. Fault rock samples from ophiolitic (mafic and ultramafic) rocks and accretionary complexes (shale, sandstone, volcanics, ophiolite fragments) are mostly made of vermiculite and include minor amounts of smectite and chlorite according to our XRD measurements. Although the low shear strength of vermiculate may trigger aseismic slip at shallow depths with change in pore water pressure, it is possible that there may be no correlation between bedrock lithology and creeping, considering the poorly known seismic history of the EAF.This study is supported by TÜBİTAK Project no. 118Y435.Keywords: earthquake, East Anatolian Fault, creep, fault rocks
Alternative applications of dense geophysical measurements in plot-scale digital soil mapping
Authors: Pásztor László , Tóth Tamás , Hermann Tamás , Szatmári Gábor , Benő András , Kovács Gábor , Koós Sándor , Árvai Mátyás , Mészáros János
Published: February 2023

 In the hilly south-western region of Hungary a 23 hectare, slightly sloping agricultural plot was surveyed with various proximal sensing techniques, basically to support its precision management. An UAV-based hyperspectral  sensor (Cubert UHD185) provided the spectral characteristics (in the form of a hyperspectral ortho-mosaic) together with the Digital Elevation Model of the plot. Detailed geophysical measurements were also carried out. Electrical conductivity was surveyed by a GF Instruments CMD-Explorer and a CMD-Explorer Mini. Gamma-ray data (U, Th, K és Total Count) was collected using a GF Instruments Gamma Surveyor Vario 2048-channel geo-physical gamma-ray spectrometer. Magnetic field was measured with a Geometrics G-858 magnetometer. Soil samples were collected in a 50 x 50 meter regular grid at 86 locations from the upper 0-30 cm. In the laboratory pH(KCl), consistency, salt, CaCO3, SOM, NO2-NO3-N, P2O5, K2O and Na content were measured.Spatial distribution of primary soil properties was predicted using different combinations of predictor datasets and various machine learning methods and with two differing concepts.While airborne hyperspectral data and terrain derivatives are available in spatially exhaustive (quasi-continuous) image format, underground geophysical data are basically generated as densely sampled point-like observations. According to general approach, these geophysical data are “simply” rasterized and then also used in spatially exhaustive form. In the recent study, we tested an alternative approach by using dense geophysical measurements as spatially non-exhaustive ancillary information to support the digital mapping of primary soil properties. First, soil features were estimated purely by geophysical auxiliary data as predictors, basically, establishing geophysical pedotransfer functions. Then predictions were used to infer spatially dense, estimated soil property data at geophysical measurement locations, which are more numerous by orders. Finally, soil property maps were derived by using (i) dense, inferred soil estimates as observation data and (ii) high-resolution spectral and terrain-based predictors. The results were evaluated and compared to those, which were produced using rasterized geophysical data.Our paper will present the comparison results, the experienced similarities and dissimilarities and discuss the applicability of dense geophysical measurements as spatially non-exhaustive ancillary information to support the digital mapping of primary soil properties. Acknowledgment: Our research has been supported by the Hungarian National Research, Development and Innovation Office (NRDI; Grant No: K 131820).
Lithospheric rheology and strength in La Palma Island (Canary archipelago)
Authors: Martín-Velázquez Silvia , Gomez-Ortiz David , Martín-Crespo Tomás , De Ignacio Cristina , Arnoso José , Montesinos Fuensanta G.
Published: February 2023

The Canary Islands are an archipelago of eight islands and several islets in the Atlantic Ocean that have been built up by intraplate magmatism. The more recent subaerial eruption took place in La Palma Island during the last four months of 2021 (September 19th to December 13th). This volcanic activity formed the Tajogaite volcanic vent and several minor vents following an eruptive fissure roughly trending N310ºE. The eruption was preceded by intense shallow (<12 km depth) volcanotectonic activity that continued during the whole eruptive process, reaching more than 11,000 earthquakes located. After the first shallow pre-eruptive seismic swarm, the seismicity was mainly located at two different depth levels with hypocenters located at 10-15 and 30-40 km depth.Seismicity record in the island for previous historical eruptions is very scarce and we have used this seismic episode to explore the lithospheric strength in this intraplate geodynamic setting corresponding to an old (~156 Ma) oceanic lithosphere. Geotherms and brittle and ductile rheological laws with different thermo-mechanical properties have been used to calculate strength envelopes. We have combined the study of the lithospheric strength and the vertical distribution of the seismicity from that period to estimate the extension of the brittle mechanical layer that conditioned the hypocentral locations.
Using statistical emulation to quantify microphysical uncertainties for the Andreas hailstorm in 2013
Authors: Frey Lena , Hoose Corinna , Kunz Michael , Miltenberger Annette , Kuntze Patrick
Published: February 2023

We investigate microphysical uncertainties in hailstorms using statistical emulation in a single model framework with the objective to disentangle the relative contributions from aerosols, microphysical parameters and environmental conditions to the uncertainty in cloud-, precipitation- and hail-related parameters.Our selected case study is the Andreas hailstorm on 28 July 2013 in the Neckar Valley and over the Swabian Jura in Southwest Germany. We perform model simulations on cloud-resolving scale with the numerical weather prediction model ICON coupled with the aerosol module ART (ICON-ART). We use a two-moment cloud microphysics scheme with a representation of ice nucleation by dust aerosols.We generated a perturbed parameter ensemble (PPE) to sample uncertainties in cloud-, precipitation- and hail related parameters. Six parameters from the categories aerosols, microphysics and environmental conditions were jointly perturbed, namely the cloud condensation nuclei (CCN) and ice nuclei (IN) concentrations, the riming efficiency of graupel and hail, the convective available potential energy (CAPE) and vertical wind shear. The defined parameter ranges are based on forecast analysis and literature. We used the maximin Latin hypercube algorithm to distribute the parameters well-spaced in the six-dimensional parameter uncertainty space. For these six parameters, an ensemble of 90 members was generated and in addition a smaller independent ensemble of 45 members serves for validation.We used the Gaussian process emulation and developed emulators for hail- and precipitation related output variables. To quantify contributions to the uncertainty in the output variables from the perturbed parameters individually as well as interactions between them, a variance-based sensitivity analysis was performed. We will present first results, which reveal the importance of the CCN concentration for controlling the number concentration of hail particles as well as the CCN concentration and environmental conditions for controlling the amount of hail and precipitation in the model. The geographical distribution of hail and precipitation shows a large variety among the ensemble members, with storm tracks shifted further to the north or south compared to the reference simulation. The path of the storm track is thereby mainly controlled by CAPE and the vertical wind shear, however, aerosol parameters seem to be important for the development of multiple storm tracks. 
Aerosol source identification in the spring and summertime central Arctic Ocean using high-resolution mass spectrometry during MOSAiC.
Authors: Heutte Benjamin , Dada Lubna , Angot Hélène , El Haddad Imad , Chen Gang , Dällenbach Kaspar R. , B. Pernov Jakob , Beck Ivo , Quéléver Lauriane , Laurila Tiia , Jokinen Tuija , Schmale Julia
Published: February 2023

The Arctic region is undergoing considerable changes and is warming at a rate three to four times as fast as the rest of the world. Aerosols, which can originate from natural or anthropogenic sources, both of which can be locally emitted or long-range transported, play a crucial role in the Arctic radiative balance by directly absorbing or scattering incoming solar radiation or indirectly by changing cloud properties and modulating cloud formation mechanisms. Here, we investigate the sources of anthropogenic and natural aerosols in the central Arctic Ocean, using data collected during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition with a high-resolution time-of-flight aerosol mass spectrometer. Using positive matrix factorization on the organic fraction of aerosols during spring and summertime (March – July), we identified six distinct chemical sources of organic aerosols (OA): a hydrocarbon-like factor, a Haze factor, two factors related to two extreme events of warm and moist air mass intrusions (WAMI) in mid-April, an Arctic oxygenated factor, and a Marine factor. We also describe the geographical origin of these factors, inferred from a potential source contribution function applied on 3-hourly back-trajectories. Together, these results suggest that OA from Eurasian anthropogenic origin (including the two extreme WAMI events in mid-April) dominate the central Arctic OA budget until at least the month of May, where episodic spikes in naturally-sourced marine OA, originating from the Fram Strait marginal ice-zone start to become important through June and July. We also highlight a hitherto unreported highly-oxygenated organic factor, whose temporal variability is closely related to that of particulate ammonium (maximum concentration in May) and whose geographical origin, in the Canadian archipelagoes, could indicate a co-emission mechanism of organic aerosols and ammonia from Arctic seabird colonies.
Factors influencing the long-term development of sediment dynamics in proglacial channels in the European Alps
Authors: Betz-Nutz Sarah , Himmelstoß Toni , Altmann Moritz , Rom Jakob , Fleischer Fabian , Haas Florian , Becht Michael , Heckmann Tobias
Published: February 2023

The system of proglacial streams in the Alps has experienced significant changes since the end of the Little Ice Age. Previous studies showed different patterns of aggradation and degradation in proglacial channels over time. This leads to the question of which factors determine the sediment dynamics in the channels and on their floodplains in the long term with ongoing glacier melting. Possible influencing variables are the distance of a channel section to the recent glacier tongue and the percentage of glaciation in the catchment area. Moreover, we suppose an influence of local topographic characteristics such as the slope gradient and the width or confinement of the channel. In addition to these factors, there is also the question of whether large individual events overlay a trend of aggradation or degradation.In order to analyse the long-term sediment dynamics in channels and the factors influencing it, we used numerous digital elevation models (DEMs) covering several decades and different streams within three main catchments (Kaunertal and Horlachtal in Tyrol and Martelltal in South Tyrol). The DEMs were generated from aerial images dating back until 1953. From the 2000s on, airborne LiDAR datasets and DEMs based on drone images were available. This data basis enables a comparative investigation and the identification of local topographic influences.
Seismic constraints on the evolution of hydrothermal circulation beneath Lucky Strike volcano, Mid-Atlantic Ridge
Authors: Bohidar Soumya , Crawford Wayne , Cannat Mathilde
Published: February 2023

Lucky Strike volcano is the central edifice of the Lucky Strike segment, Mid-Atlantic Ridge. Its summit overlies an axial magma chamber (AMC), 3-3.8 km beneath the seafloor, and hosts one of the largest known deep-sea hydrothermal fields. Local seismicity beneath the hydrothermal field has been monitored since 2007 as a part of the EMSO (European Multidisciplinary Seafloor and water column Observatory)-Azores observatory by 5 OBSs with yearly redeployments. In a 12-year (2007-2019) earthquake catalog (noncontinuous), we observe continuous low magnitude seismicity (ML ~ -1 to 0), focused mainly 0.5-2 km above the AMC, suggesting that thermal contraction of rocks, possibly combined to deformation induced by volume changes during hydrothermal alteration, at the base of a single limb along-axis hydrothermal cell is the primary source of this seismicity. We thus interpret the seismicity clusters, with horizontal extent 1200 to 1800 m2, as zones of enhanced heat extraction, in the lower part of the hydrothermal downflow zone.We present the evolution of this hydrothermally-induced seismicity over the 12 years of the catalog. We observe three lateral 400-800 m shifts of the main seismicity clusters. The first and second shifts are small and could be explained by a fortuitous combination of network-based biases, picking error and/or change in the shallow seismic velocity structure of the volcano. The third shift, occurring during a catalog gap between June 2013 and April 2015, is ~800 m eastward and corresponds to a change in the seismicity distribution from a patch above the AMC to a vertical pipe-like pattern, indicating a real change in the hydrothermal circulation. We propose that this shift is driven by recent magmatic injections above the AMC, and/or to the opening of new tectonic cracks, enhancing local permeability and allowing for more efficient cooling above the shallower region of the AMC roof.We also observe three Higher Seismic Activity (HSA seismic rate > 18 events/week) periods: April-June 2009, August-September 2015, and April-May 2016. The 2009 HSA period was the most intense: it lasted ~13 weeks, starting with a relatively higher magnitude event (ML = 1.7), and culminating in June after another higher magnitude (ML = 1.8) event. Most of the events clustered 0 to 1 km above the AMC reflector, with a few deeper events (down to only 800 m below the AMC reflector) during the culmination period. Although we do not have focal mechanisms to test this hypothesis, we propose that this HSA period resulted from tectonic events opening enhanced local permeability channels for downgoing hydrothermal fluids, and leading to higher heat extraction by the hydrothermal system.
Investigating ice cloud formation mechanisms from satellite observations and Lagrangian transport and microphysics models
Authors: Saiprakash Athulya , Konjari Patrick , Horner George , Rolf Christian , Krämer Martina , Sourdeval Odran
Published: February 2023

Ice clouds are challenging because of the high complexity and diversity of their composition  (microphysics) as well as formation and growth processes. As a result, there has been little constraint from observations until recently, resulting in significant limitations in our understanding and representation of ice clouds. A major problem with satellite measurements is the lack of information on the environmental context, which is necessary to identify and understand the formation mechanism and evolution of clouds; these renditions indeed only represent a snapshot of the state of a cloud and its microphysical properties at a given time. This work tackles this issue by providing additional metrics on ice cloud history and origin along with operational satellite products.Here, we present a novel framework that combines geostationary satellite observations with Lagrangian transport and ice microphysics models, in order to obtain information on the history and origin of air parcels that contributed to their formation. The trajectory of air parcels encountered along the DARDAR-Nice track has been traced using the air mass transport models CLAMS (Chemical LAgrangian Model of the Stratosphere). CLaMS - Ice model is jointly used to simulate cirrus clouds along trajectories derived by CLaMS. This approach provides information on the cloud regime as well as the ice formation (in-situ vs liquid origin) pathway. For tropical cirrus of convective origin, a Time Since Convection dataset from geostationary observations can also be incorporated into this approach. Preliminary results of this approach obtained on case studies representative of multiple cloud types will be shown here.
Influence of sun cups on surface albedo of wet Alpine snowpack
Authors: Carletti Francesca , Brouet Loïc , Lehning Michael , Bavay Mathias
Published: February 2023

In high elevation Alpine areas, characterised by high snow accumulation and radiation-driven melt processes, the formation of peculiar ablation features called sun cups can be observed. Sun cups likely influence the energy and mass balance of the wet snowpack by locally reducing the snow albedo, leading to an enhanced ablation in the hollows. To our knowledge, these phenomena are to date poorly explored in the literature and little to no attempts have yet been made to study their evolution in time and correlate them with meteorological forcings and energy fluxes over the wet snowpack.The dynamics of the sun cups was investigated at the high elevation Alpine site of Weissfluhjoch (Davos, Switzerland) over the Spring of 2022. At the site, the snow surface was mapped on an hourly basis by means of a fixed, automated high-resolution 3D terrestrial laser scanner. Snow height maps were obtained by processing the registered point clouds.Sun cups were individually and automatically detected over the snow surface maps by a delineation algorithm in Python. The evolution of sun cups in time was studied with respect to their maximum depth and cross-section.The maximum depth and cross-section evolution of sun cups showed a high correlation with the measured albedo, especially when they are fully-formed. This finding suggests that peculiar snow surface formations that can be detected by means of remote sensing systems can give valuable additional information about the ongoing processes within the wet snowpack, paving the way to a radar-assisted modelling of the snowmelt dynamics. In an era of increasing concern over the availability of water resources, a better understanding and modelling of snowmelt dynamics is of major importance, especially in remote areas where accurate predictions are required for operational purposes (e.g. hydropower and irrigation).
Trees as hillslope debris flow brakers
Authors: Hollard Niels , von Moos Christine , Dorren Luuk
Published: February 2023

Worldwide, landslides and hillslope debris flow cause major infrastructure damage and fatalities. It is widely recognized that forests can prevent the release of a landslide by reinforcing the soil with the roots and positively influence the water balance. However, the question remains whether and how trees affect the runout of hillslope debris flows. The objective of this study was to quantify the potential braking effect of trees and the influence of different forest structures in the runout zone of hillslope debris flows. We therefore combined an analysis of historical hillslope debris flow events in the forest and on open land with laboratory tests. The analysis of the historical events showed a general tendency that forest has a positive effect on the runout, in particular for smaller events (release area < 300 m2). The runout length significantly decreased with an increasing tree density. In addition, significantly more material was deposited behind thicker trees. This suggests that a well-structured stand with a high stem number, but also occasional large diameters, offers ideal protection against hillslope debris flows in the runout zone. The results of the laboratory tests indicate that the braking effect of different forest structures (dense, open, with gaps) is always given in comparison to a situation without forest, and this at lower (16%) and higher (20%) water contents. Generally, the effect of the trees was more pronounced for soils with a lower water content. Although the influence of the forest was always highlighted in comparaison to the situation without forest, no significant influence was showed between the three forest structures.
On the Origin and Stability of Thermochemical Heterogeneities
Authors: Stein Claudia , Zander Carolin , Hansen Ulrich
Published: February 2023

The presence of a large variety of complex structures at the core-mantle boundary (CMB) has been reported. Besides the two prominent structures, the large low shear-wave velocity provinces (LLSVPs), also smaller structures, the ultra-low velocity zones (ULVZs), have been detected. The seismically observed locally sharp boundaries of LLSVPs and their stability in space and time suggests that these structures are possibly induced by chemically distinct material that forms from a layer above the CMB. Therefore models of mantle convection made some ad hoc assumptions in order to simulate the dynamics of this layer. In particular, density and mass of a compositionally enriched layer were prescribed. Both conditions are critical for the dynamics but hardly constrained. This dense CMB layer is considered to be either a remnant of the magma ocean or formed by segregated slabs or by core-mantle interaction processes. Various metal-silicate interaction mechanisms at the CMB have been considered such as diffusion-controlled enrichment of molten iron. Employing a thermochemical mantle convection model, we analyse the penetration of dense material by applying a diffusive chemical influx at the base of the model. In our simulations a dense basal layer develops self-consistently. We find that the chemical diffusion is strongly affected (and promoted) by the convective flow within the mantle. Convection-assisted diffusion yields a large compositional influx mainly in the areas where slabs spread over the bottom boundary and sweep dense material aside. Like in the cases with a prescribed dense layer (primordial layer scenario) this process leads to chemically distinct piles. We compare the spatial and temporal stability of the chemical structures resulting in the cases with a chemical influx to cases of the primordial layer scenario. Typically the chemical structures in the influx cases are much smaller and therefore more suited to explain ULVZs, but the structures are also more persistent due to the constant chemical influx. Combining the influx with the primordial layer scenario can possibly explain the simultaneous existence of LLSVPs and ULVZs along with the observation of a core-like isotopic composition in the mantle.
Investigating the dynamics of cusp bifurcations: A conceptual model for glacial-interglacial cycles
Authors: Ajagun-Brauns Jade , Ditlevsen Peter
Published: February 2023

An investigation into the dynamics of a two-parameter family of non-linear differential equations inspired by MacAyeal (1979) reveals the utility of simple conceptual models in understanding climate response to forcing. A slow-fast model is used to explain the non-linear response of the climate to insolation forcing after the Mid-Pleistocene Transition (MPT) which produces the saw-toothed glacial cycles in the paleoclimate record. Global ice volume is taken to be a function of two independently varying parameters, the solar insolation and ‘alpha’, a secondary control parameter. The pleated cusp geometry of the model, due to the addition of the second control allows the system to exhibit both smooth changes and sudden discontinuous transitions from one stable solution to another, producing the gradual increase and sudden decrease in global ice volume observed in the paleoclimate record.  The control parameter alpha is suggested to be related to internal dynamics of the climate system, proposed to be a measure of glacial-oceanic interaction, which varies due to glacial isostatic adjustments of the bedrock.  The transition in period of glacial cycles at the MPT is suggested to occur as a result of northern hemisphere glaciers exceeding a critical threshold, which allows alpha to become larger, causing the asymmetric, higher amplitude glacial cycles with quasi-period of 100kyr of the late Pleistocene. ReferenceR. MacAyeal, ‘A Catastrophe Model of the Paleoclimate Record’ , Journal of Glaciology , Volume 24 , Issue 90 , 1979 , pp. 245 – 257. 
Paleoseismicity of Northern Cyprus, implications from coastal geomorphology and geochronology
Authors: Yildirim Cengiz , Melnick Daniel , Tüysüz Okan , Altınbaş Cevza Damla , Jara-Munoz Julius , Tsanakas Konstantinos , Özcan Orkan , Strecker Manfred
Published: February 2023

The Cyprus Arc is one of the major sources of earthquakes in the Eastern Mediterranean Region. There is limited large-magnitude earthquake activity during the instrumental period. Still, archeoseismological data imply the occurrence of large-magnitude earthquakes that hit the island and gave rise to casualties and destructions. Nevertheless, these data are insufficient to give information about the source of the earthquakes. In this study, we focussed on coastal geomorphology to unravel paleoseismic activity, at least generated by near offshore faults, that released sufficient seismic energy to deform the shoreline in Holocene.We mapped coseismically uplifted abrasion platforms, tidal notches, fish tanks and a surface rupture implying active near offshore faults in Holocene. The elevation of paleo shorelines varies between 0.4 m to 3 m above sea level, indicating multiple occurrences of paleo earthquakes. Our radiocarbon 14C ages from biological markers (algal rims, etc) indicate that the coseismic uplift of the shoreline starts from 4,5 ka to 1.2 ka BP.The ages of the paleoearthquakes display non-uniform spatial distribution and show migration of paleoearthquakes from west to east, especially along the island's northern coast. This study is supported by Istanbul Technical University Research Fund (Project No: 37548) and Alexander von Humboldt Foundation, Germany.
OGGM-Edu: an open-source educational platform about glaciers and glacier modelling
Authors: Vlug Anouk , Schmitt Patrick , Schuster Lilian , Holmgren Erik , Schroeder Marie , Ultee Lizz , Champollion Nicolas , Marzeion Ben , Maussion Fabien
Published: February 2023

OGGM-Edu (https://edu.oggm.org) is an educational platform about glaciers, with the main goal to provide tools and materials for instructors who want to teach about glaciers at secondary schools, in workshops or at universities. Interactive web applications and open access images provide materials for entry-level classes with no experience in physics or programming. Jupyter notebooks at various levels of complexity offer guidance to run and develop simple modeling experiments in the python programming language. OGGM-Edu follows a decentralized open source model: we encourage our users to mix and remix our templates, and offer technical help to develop new classes, run the notebooks on a dedicated cloud service, or translate our materials to various  languages. With this contribution, we are looking to connect with educators and scientists in all fields of geosciences interested in online teaching resources.