bluuebunny/crossref_metadata_2025 huggingface dataset:
Testing icehouse cyclicity and seawater dynamics on an ancient carbonate platform with Nd isotopes (Carboniferous, southern Kazakhstan)
Authors: Belka Zdzislaw , Skompski Stanisław , Jakubowicz Michał , Dopieralska Jolanta , Walczak Aleksandra , Mustapayeva Sezim
Published: March 2022

Over the past decades, neodymium isotopes have received considerable attention in palaeoceanography as a tool for reconstructing past seawater circulation, local weathering inputs, and sea-level changes. In this study, we have investigated the Nd isotope composition of Serpukhovian (Carboniferous) carbonates of a shallow-water succession to test icehouse cyclicity and seawater dynamics on the Karatau carbonate platform in southern Kazakhstan. The cyclic succession formed in response to glacio-eustasy and composed of subtidal and intertidal limestones displays a large variation in the εNd(326 Ma) values from –1.6 to +4.3, corresponding to differences in the isotopic composition of two seawater masses present in the adjacent Uralian–Turkestan Ocean during the Serpukhovian, highly radiogenic deep water and less radiogenic surface water. The Nd isotope excursions within the icehouse cycles are more complex than simple transgressive-regressive cycles. They probably reflect a temporal pattern of the sub-Milankovitch climatic perturbations during the interglacial periods in the Carboniferous. The episodic appearance of rich brachiopod communities was forced by the inflow of highly radiogenic, nutrient-rich waters, presumably driven by upwelling. Nd isotope analyses of cyclic intertidal and subtidal carbonates have great potential to produce high-resolution records of seawater dynamics on shallow-water carbonate platforms.

This study was supported by the Polish National Science Centre, grant No. 2013/11/B/ST10/04751.
Nutrient cycling and plant trait variation - two crucial processes for simulating the community assembly and productivity of tropical forests
Authors: Dantas de Paula Mateus , Forrest Matthew , Langan Liam , Bendix Jörg , Homeier Jürgen , Velescu Andre , Wilcke Wolfgang , Hickler Thomas
Published: March 2022

Community assembly in highly diverse tropical rainforests is poorly understood and advancing our understanding is crucial for predicting ecosystem responses to future environmental change. Dynamic vegetation models which include plant trait variation are able to produce realistic plant communities by ecological filtering under climatic and edaphic drivers. Building upon more than a decade of field research in the biodiversity hotspot of the mountain rainforest in southern Ecuador, we implemented plant trait variability and improved soil organic matter dynamics in a widely used regional to global dynamic vegetation model (LPJ-GUESS) in order to explore how nutrients may influence community trait assembly and productivity along an altitudinal gradient.

In the new model version LPJ-GUESS-NTD (where NTD stands for nutrient-trait dynamics), each plant individual can possess different trait combinations which determine their demand for nutrients (N and P) and competiveness along conservative – acquisitive strategies.   Nutrient availability is determined by the stoichiometry of the source organic matter and edaphic constraints to its decomposition, producing a feedback between vegetation traits and their drivers. Final community trait composition emerges via ecological sorting. Further model developments include mycorrhizal nutrient uptake.

The new model version reproduced the main observed community trait shift and related vegetation processes along the elevational gradient, but only if nutrient limitations to plant growth were activated. In turn, when traits were fixed, low productivity communities emerged due to reduced nutrient-use efficiency. The results strongly suggest that interactions between plant traits and nutrient limitations are crucial for community assembly and ecosystem functioning in our study area and probably in other systems where water is not limiting. Future studies based on the LPJ-GUESS-NTD model will include further traits based on the belowground carbon economy and collaboration with mycorrhiza, and may provide important insights concerning the role of functional diversity for ecosystem resilience under climate change and increased anthropogenic nutrient deposition.
El Niño diversity during the Holocene in relation to mean state changes
Authors: Abdelkader Di Carlo Isma , Braconnot Pascale , Marti Olivier , Carré Matthieu , Elliot Mary
Published: March 2022

A consensus has not yet been reached when it comes to the long-term changes in ENSO diversity. Indeed, for models that simulate larger warming in the East Pacific, some studies show an increase of Eastern Pacific (EP) events, and a decrease in Central Pacific (CP) events, or the opposite. Similar apparent contradictions also emerge from analyses of the changes in EP versus CP El-Niño events in the Holocene. In this study, we consider the Holocene period as a means to study long-term El Niño variability in a context relatively close to the present. Indeed, the Holocene period allows studying the changes related to the long-term trend induced by the long-term evolution of the Earth’s orbit and seasonal evolution induced by the orbital forcing. We use two 6,000-year-long transient simulations of the IPSL model and two different indicators to characterize El Niño events. 

This study shows that we can have opposite results on the behavior of EP and CP events depending on the type of indicator used to characterize El Niño. We will discuss the reasons for these contrasting results, as seen in two previous studies. Moreover, we will test the extent to which the types of events are induced by changes in the tropical Pacific’s thermocline.
Changes in future subdaily extreme precipitation at convection-permitting scale over an alpine transect
Authors: Roghani Bardia , Dallan Eleonora , Fosser Giorgia , Schär Christoph , Marani Marco , Borga Marco , Marra Francesco
Published: March 2022

Subdaily extreme precipitation may trigger fast hydro-geomorphic responses, such as flash floods and debris flows, which cause numerous fatalities and large damage. Compared to coarser resolution models, high-resolution models, called convection-permitting (CPMs), more realistically represent convective processes that are key for the correct representation of subdaily extremes, and thus provide higher confidence in the future extreme estimates. However, due to the high computational demands, the existing CPM simulations are only available for relatively short time periods (10–20 years at most), too short for deriving precipitation frequency analyses with conventional approaches. Recent extreme value analysis methods, based on all “ordinary” observations rather than on just yearly maxima or a few values over a high threshold, offer an opportunity for exploiting these short data records to reliably estimate return levels associated with long return periods. Here, we examine subdaily precipitation extremes from three 10-year time slices (historical 1996-2005, near-future 2041-2050, and far future 2090-2099 – under the RCP8.5 scenario) of COSMO-crCLIM model simulations at 2.2 km resolution. We focus on the Eastern Alpine transect characterised by a complex orography, where significant changes in subdaily annual maxima have been already observed. We find that, although the storms' frequency will decrease in the region, the mean annual maxima will increase continuously in the near and far future, especially at shorter durations. Investigation of extreme return levels shows a similar trend, with larger changes in the far future. A shift in the seasonality is also reported, with extremes moving from late summer-autumn (historical), to autumn (near future), and autumn-winter (far future).
Are diverse geochemists retained and thriving on the UK academic ladder?
Authors: Maters Elena , Appiah Francis , Lawrence Anya , Bots Pieter , Gagnon Jessica , Riches Amy , Bhagwat Shonil , Chi Fru Ernest , Little Susan , Ngwenya Bryne , Anand Pallavi
Published: March 2022

Evaluating Diversity and Inclusion within the (geochemistry) Academic Ladder (E-DIAL), funded by the UK’s Natural Environment Research Council, provides a snapshot of diversity and identifies barriers resulting in underrepresentation among intersectional identity groups across the UK geochemistry community. The project emphasis is on the academic ladder within UK higher education institutions (HEIs). As a multi-faceted discipline, geochemistry is central to Earth, environmental and planetary sciences, yet the first specific geochemistry workforce data is only now being collected (e.g., through the 2022 Global Geochemistry Community Survey launched by the European Association of Geochemistry and Geochemical Society). In complement to this timely society-led effort serving the international geochemistry community, our project collects original data and evidence through a UK-wide survey that captures coupled diversity and academic progression and retention data. These data are vital to catalyse policies that actively improve geochemistry career prospects for diverse talents, given that a community’s scientific potential can only be reached by including everyone. Specifically, the UK-wide survey data examines information on past and recent rates of appointment, progression and retention of both majority and under-represented groups across all levels of seniority, including research students, within UK HEIs.

In profiling geochemists’ career pathways and evidencing lived experiences (e.g., among postdocs), exclusionary obstacles are identified with resultant understanding driving revision of prevailing policies, attitudes and practices while assessing implementation effectiveness at HEIs with, for example, differing diversity certifications (e.g., Athena Swan or Race Equality Charters). Findings will test the hypothesis that “there is an erosion of diversity within geochemistry careers.” To accelerate widespread change, E-DIAL will engage in diplomacy and action at institutional, funding agency and parliamentary levels. Our approach optimises study effectiveness by ensuring that project findings and recommendations for reform within UK HEIs reach communities and decision makers at all levels, with the intention of influencing UK system change to improve diversity and inclusion while establishing practice for continued monitoring. As a national-level project linked to society efforts on the global stage, E-DIAL provides a starting model for similar studies to be carried out among other nations. We therefore urge wider funding agencies to engage in and sustain financial support of such collaborative cross-disciplinary research because this work and its impact on STEM governance is critical to advancing justice, diversity, inclusion, equity and excellence in and beyond academia.
Commitment as Lost Opportunities
Authors: Martinez Montero Marina , Crucifix Michel , Botta Nicola , Brede Nuria
Published: March 2022

In the context of climate change, the word "commitment" was originally used to denote how much extra warming is to be expected eventually given a certain fixed concentration of CO2. The notion has evolved and now it is customary to encounter terms such as "constant emissions commitment", "sea level rise commitment" and "zero emissions commitment". All these notions refer to how much change with respect to the current climate state is expected at a given point in the future considering our current climate state and specified future anthropogenic emissions.

Here, we propose thinking about commitment as available options for future action that will allow future decision makers to avoid harmful futures. The definition requires the identification of unwanted outcomes e.g., too high temperature or too fast sea level rise and the specification of a range of possible future anthropogenic emission/intervention scenarios. Given an initial climate state, the measure of commitment is based on the diagnosis of which of those emission/intervention scenarios yield futures safe from the unwanted outcomes. This new definition of commitment explicitly captures the notion of legacy: It measures the range of options that the next generations have at their disposal to avoid harmful futures.

We illustrate the definition and methodology with a simple model featuring ice sheet tipping points and ocean carbonate chemical balance. After having introduced the model, we specify the considered future anthropogenic emission/intervention options available, along with the considered unwanted outcomes. We show how the safe options available for future generations would change in time if we were to follow some of the most standard emission scenarios used in the literature.
The organic matter effect on Fe(II) oxidation kinetics within coastal seawater
Authors: González-Santana David , Santana-Casiano J. Magdalena , Devresse Quentin , Hepach Helmke , Santana-González Carolina , Quack Birgit , Engel Anja , González-Dávila Melchor
Published: March 2022

Iron is an essential nutrient that limits primary productivity in up to 30% of the world’s ocean. Redox and complexation reactions control its solubility and therefore the fraction of dissolved and bioavailable iron. The iron (II) oxidation kinetic process was studied at 25 stations in coastal seawater of the Macaronesia region (around Cape Verde, the Canary Islands and Madeira). Laboratory experiments were carried out to study the pseudo-first-order oxidation rate constant (k’, min-1) over a range of pH (7.8-8.1) and temperature (T; 10-25ºC). Measured k’ varied from the calculated k’ (k'cal) at the same T, pH and salinity (S) at most stations. Measured iron (II) half-life times (t1/2=ln2/k’; min) at the 25 stations ranged from 1.8-3.5 min (mean 1.9±0.8 min) and for all but two stations were lower than the theoretically calculated t1/2 of 3.2±0.2 min. The biogeochemical context was considered by analysing nutrients and variables associated with the organic matter spectral properties (CDOM and FDOM). A multilinear regression model indicated that k’ can be described (R=0.921, SEE=0.064 for pH=8 and T=25ºC) from a linear combination of three organic variables.

k’OM = k’cal -0.11* TDN + 29.9 * bDOM + 33.4 * C1humic

where TDN is the total dissolved nitrogen, bDOM is the spectral peak obtained from coloured DOM analysis when protein-like or tyrosine-like components are present and C1humic is the component associated with humic-like compounds obtained from the parallel factor analysis (PARAFAC) of the fluorescent DOM. Experimentally, k’ and k’OM provide the net result between the compounds that accelerate the process and those that slow it down. Results show that compounds with nitrogen in their structures mainly explain the observed k’ increase for most of the samples, although other components could also present a relevant role.
Saturated hydraulic conductivity estimation of layered soil in 1D from Beerkan Experiment
Authors: Yilmaz Deniz , Moret-Fernandez David , Latorre Borja , Angulo-Jaramillo Rafael , Lassabatere Laurent
Published: March 2022

In the last decade, the development of methodologies based on Beerkan infiltration (ring or disk infiltrometry technique with null constant water head) analysis allows today to estimate the hydraulic properties of surface soils with increasing accuracy. In particular, the 3D model of Haverkamp et al. (1994) and its two-term (BEST methods) and four-term (4T) expansions (Moret-Fernández et al., 2020) have demonstrated their robustness. The analysis of the transient part of cumulative Beerkan infiltration allows the simultaneous estimation of the sorptivity S and the hydraulic conductivity at saturation Ks. Very recently presented, the sequential analysis (SAI) of Beerkan data (Moret and Fernandez et al., 2021) applied to stratified soils columns allows delimiting the part of the Beerkan infiltration curve governed by the upper layer and estimating its thickness. This approach opens new perspectives for using Beerkan water infiltration, especially for estimating the conductivity of the underlying porous medium. Numerical Beerkan infiltration of layered soils combination in 1D were produced using van Genuchten-Mualem model and Hydrus 1D software.  Numerical curves were subject to SAI method to estimate the upper horizon soil hydraulic properties and the regime state of the infiltration flow allowed the estimation. Therefore, it is possible under certain assumptions to estimate the hydraulic conductivity of the underlying soil in 1D. This is the first step towards the determination of stratified soils hydraulic properties. This approach will allow new theoretical development for the extension to three-dimensional water infiltration into layered soils and relative hydraulic characterization of soil layering.

Moret-Fernández, D., Latorre, B., López, M.V., Pueyo, Y., Lassabatere, Angulo-Jaramillo, R., Rahmati,M., Tormo, J., Nicolu, J.M. (2020). Three- and four-term approximate expansions of the Haverkamp formulation to estimate soil hydraulic properties from disc infiltrometer measurements. Hydrological Processes, 34 (26), 5543-5556.  

Haverkamp, R., Ross, P. J., Smettem, K. R. J., & Parlange, J. Y. (1994). Three‐dimensional analysis of infiltration from the disc infiltrometer: 2. Physically based infiltration equation. Water Resources Research, 30(11), 2931-2935.

Moret-Fernández, D., Latorre, B., Lassabatere, L., Di Prima, S., Castellini, M., Yilmaz, D., & Angulo-Jaramilo, R. (2021). Sequential infiltration analysis of infiltration curves measured with disc infiltrometer in layered soils. Journal of Hydrology, 126542.
Interannual olive yield modulation forced by climate stressors in Italy: a composite index approach to support crop management 
Authors: Di Paola Arianna , Di Giuseppe Edmondo , Pasqui Massimiliano
Published: March 2022

Even though a large part of the Italian peninsula is characterized by a Mediterranean climate intrinsically highly suitable for olive cultivation, farmers may experience variable agronomic and management costs due to interannual yield variability. A synoptic picture of major climate stressors and their ongoing impacts on olive yield variability at a broad spatio-temporal scale are scarce, but, if identified, could enhance the development of actionable services to alert stakeholders of potential climate risks. We analyzed Italian olive yield data from the Italian National Statistics Institute (ISTAT), aggregated at the provincial level, during 2006-2020, and several climatic variables from Reanalysis v5 (ERA5) of the European Centre for Medium-Range Weather Forecasts (ECMWR) to i) explore olive yields trends and inter-annual variations over the whole peninsula; ii) identify major climate stressors likely responsible for the largest drops in yield; iii) build a composite index that summarizes the risk of having exceptionally low yields due to the occurrence of multiple climate stressors; to this end, we defined two major classes of yield, namely exceptionally low and high yields (LY and HY, respectively), and explored the climatic variables, aggregated on a bimonthly time scale, determining yield in outcomes. It is worth noting that the use of bimonthly periods provides a means of examining the seasonal effects of stressors while providing the basis for near-real-time forecasting. Moreover, five years (i.e., 2009, 2011, 2014, 2018, and 2019) characterized by a conspicuous number of both LY and HY were focused to examine whether the composite risk index has application at more local scales. Results are discussed and some possible explanations based on the current knowledge of olive developmental ecology are provided. We suggest our approach as a promising yet still-in-progress work that could pave the way to an integrated meteorological seasonal forecast system to provide timely insight on factors affecting within-season yield development.   
Oxygen fugacity characteristics of lithospheric mantle peridotite in northern Xingmeng orogenic belt
Authors: Liu Jinlin , Li Huibin
Published: March 2022

Spinel peridotite xenoliths have been found in Cenozoic basalts from the Nuomin and Keluo areas in the northern Daxinganling. The Mg content of olivine in the mantleperidotite indicates that the upper mantle in the study area is partially refractory. According to the olivine content and Fo diagram, a part of peridotite xenoliths fell in the Archean and Proterozoic mantle regions, which reveals that there are remnants of ancient lithospheric mantle in the lithospheric mantle of the study area. In the study area, harzburgite and lherzolite show high oxygen fugacity values (FMQ + 1.95-3.15), which is in sharp contrast to the low oxygen fugacity values of the relatively reduced ancient lithospheric mantle. It is possible that the Paleozoic paleo Asian Ocean and Mesozoic paleo Pacific subducted successively under the Xingmeng orogenic belt, resulting in the oxidation of the lithospheric mantle at that time. K 2O (1% ～ 6%) is found in the reaction edge of mantle xenoliths. It is considered that the mantle in the study area has experienced multiple periods of K-rich meltactivity, and the source of K-rich melt may be related to the crust source material recycled by subduction.
Observations of carbon allocation in the world’s forests must match pace with vegetation model development
Authors: Babst Flurin , Friend Andrew D , Wei Jingshu , von Arx Georg , Papale Dario , Peters Richard L
Published: March 2022

The data requirements of vegetation models are changing. For more than a decade, the community has been developing “next-generation” models that should be globally applicable and at the same time incorporate great process detail. The individual tree emerges from this development as the finest scale at which carbon, water, and nutrient dynamics can be realistically simulated. As such, precise tree-level observations of the relevant processes would ideally be available from across all forested biomes to inform and evaluate tree-centered vegetation models. This is not the case. Instead, we note a growing discrepancy between the demand for and the availability of highly-resolved measurements of carbon allocation in trees and forests.

To exemplify this discrepancy, we conducted a survey at 90 flux-tower sites from around the world that revealed priorities and deficiencies in existing data collections. We found that forest structure and aboveground carbon stocks have been ubiquitously inventoried, and that tree growth and foliage turnover have also been measured at many sites. By contrast, detailed information on water cycling, volume increment, and wood formation processes (especially belowground) are less common, as are records of tree mortality or terrestrial and airborne LiDAR that could help scale local observations. In addition, we found that the temporal resolution and length of existing time-series vary substantially across the current flux-tower network. Weighing the strengths and limitations of this and many other ecological monitoring networks, we conclude that the present data basis is insufficient to support accelerating vegetation model development.

Looking forward, we anticipate that not only the amount of tree-level observations needs to be increased – especially in tropical and boreal systems – but that the consistency, scalability, and predictability of forest carbon cycle observations needs to be improved. We also propose that intensive long-term monitoring sites be strategically paired with manipulative experiments at comparable sites to better connect past, present, and expected future dynamics. For this, we propose a versatile experimental framework and call for a community-wide discussion on the “yield on cost” of various field observations. We also list a number of key questions on how to best build and maintain cross-scale data archives in support of tree-centered vegetation modelling.
Identifying links between hydroclimatic variability and economical components using stochastic methods
Authors: Arvanitidis Ilias , Diamanta Marianna , Sargentis G.-Fivos , Iliopoulou Theano , Dimitriadis Panayiotis , Koutsoyiannis Demetris
Published: March 2022

Since ancient times water has been a substantial factor for driving economic growth, as abundance in water resources can be linked to the development of prosperous communities. This study examines the effect of water resources availability on different sectors of the economy, by identifying components of Gross Domestic Product which are most affected by key water cycle processes and water infrastructures. In this analysis, we investigate the correlation among the above processes, on both temporal and spatial scale with the implementation of stochastic methods, in order to assess the sensitivity of the economy to hydroclimatic variability. We also take into consideration the effect of hydroclimatic extremes such as droughts and the limitations they may impose on growth. Differences between climate zones are taken into consideration by the Köppen climate index.
Mapping and kinematic history of active landslides in Panachaikon Mountain, Achaia (Peloponnese, Greece) by InSAR Time Series analysis and its relationship to rainfall patterns
Authors: Tsironi Varvara , Ganas Athanassios , Karamitros Ioannis , Efstathiou Eirini , Koukouvelas Ioannis , Sokos Efthimios
Published: March 2022

We investigate the kinematic behaviour of active landslides at several well-known locations around the Panachaikon Mountain, Achaia (Peloponnese, Greece), using space geodetic data (InSAR/GNSS). We process LiCSAR interferograms produced by Sentinel-1 (C-band) acquisitions using the open-source software LiCSBAS and we obtain average displacement maps for the period 2016-2021. The maximum displacement rate of each landslide is located at about the centre of each landslide. The average E-W velocity of the Krini landslide is 4 cm/yr (towards east) and 1 cm/yr downwards. The line-of-sight (LOS) velocity of this landslide compares well to a co-located GNSS station within (±) 3 mm/yr (25mm/yr for InSAR and 28mm/yr for GNSS for the descending orbit). Our results also suggest that there is a correlation between rainfall and landslide motion. A cross-correlation analysis of our data suggests that the mean time lag was 13.5 days between the maximum seasonal rainfall and the change of LOS displacement rate. Also, it seems that the amount of total seasonal rainfall controls the increase of displacement rate as 40-550% changes of the displacement rate of the Krini landslide were detected, following a seasonal maximum of rainfall values at the nearby meteorological station. A large part of this mountainous region of Achaia suffers from slope instability that is manifested in various degrees of ground displacement (detectable using space geodesy) affecting greatly its morphological features and inhabited areas.

We acknowledge funding by the project PROIΟΝ “Multiparametric microsensor monitoring platform of the Enceladus Hellenic Supersite” co-financed by Greece and the European Union
3D Deep Electrical Resistivity Tomography of the Lusi Eruption Site in East Java
Authors: Mazzini Adriano , Carrier Aurore , Sciarra Alessandra , Fischanger Federico , Winarto-Putro Anton , Lupi Matteo
Published: March 2022

Lusi is the nickname of the largest sub-aerial erupting clastic system on Earth. This sediment-hosted geothermal system relentlessly erupts since May 2006 in the East Java back-arc sedimentary basin. This spectacular system features two main active craters (~100 m in diameter each) surrounded by thousands of satellite active seeps that extend over a region of 7km2. Previous multidisciplinary studies revealed that Lusi is connected at depth with the neighboring Arjuno-Welirang volcanic complex through a system of faults (Watukosek Fault System) that extend from the volcano towards the north in the sedimentary basin. The migration of these mantle-derived fluids feeds the long-lasting activity of the eruption. Vigorous convection fuels the system and leads to geyser-like eruptive activity.

To investigate the morphology and the effect that pre-existing geological structures may have on the development of the shallow plumbing system of Lusi, we deployed a pool of 25 IRIS V-Fullwavers to conduct a 3D deep electrical resistivity tomography extending over 15 km2 around the eruption site. The inverted data reveal the structure of the subsided area hosting the region where a mix of groundwater, mud breccia, hydrocarbons and boiling hydrothermal fluids are stored. We estimate that after 12 years of Lusi's inception, a collapse region of 0.6km2 developed around the active vents. Combining the flow rate data with our geoelectrical data, we estimate a total budget of 0.47km3 of mud breccia (i.e., including the erupted volume and that trapped in the collapse zone around the carter). Our investigation also points out the link between the well-developed Watukosek Fault System and the upwelling of the deep-sourced fluids that initiated, and still drive, the development of the new-born Lusi eruption. Lusi provides the unprecedented opportunity to study the development of the early phases of a piercement structure and its impact on society. Our study highlights how fully 3D geoloectrical methods may represent a key tool to investigate and possibly mitigate geohazards.
Evidence for Presence of a Global Resonant Mode of Oscillations During High-Intensity Long-Duration Continuous AE Activity (HILDCAA) events
Authors: Rout Diptiranjan , Singh Ram , Pandey Kuldeep , Pant Tarun , Stolle Claudia , Chakrabarty Dibyendu , Thampi Smitha , Bag Tikemani
Published: March 2022

The interaction between the Sun and the Earth defines the space environment of the Earth. This interaction is complex and exhibits various time scales ranging from a  few seconds to years. The High-Intensity Long-Duration Continuous AE Activity (HILDCAA) events are mainly the manifestations of the interactions of the corotating interaction regions (CIRs) with the terrestrial magnetosphere which continues for several days. The responses of two HILDCAA events are investigated by using solar wind observations at the L1 point, magnetospheric measurements at geosynchronous orbit, and changes in the global ionosphere. This study provides evidence of the existence of quasi-periodic oscillations (1.5-2hr) in the ionospheric electric field over low latitude, total electron content at high latitude, the magnetic field over the globe, energetic electron flux and magnetic field at geosynchronous orbit, geomagnetic indices (SYM-H, AE, and PC) and the Y-component of the interplanetary electric field (IEFy) during the HILDCAA events at all local times. Based on detailed wavelet and cross-spectrum analyses, it is shown that the periodic oscillations of 1.5-2hr in IEFy are the most effective one that controls the solar wind-magnetosphere-ionosphere coupling process during the  HILDCAA events for several days. Therefore, this investigation for the first time, shows that the  HILDCAA event affects the global magnetosphere-ionosphere system with a “resonant” mode of oscillation. These results are important not only to evaluate the solar wind-magnetosphere-ionosphere coupling process during the HILDCAA events but can also help to build up a forecasting strategy in the future.
Aspects derived from the geological, geometrical, and statistical analysis of the Ticino landslide inventory
Authors: Gutierrez Amalia , Derron Marc-Henri , Jaboyedoff Michel , Pedrazzini Andrea
Published: March 2022

An inventory of more than 2000 mass movement events from the last 20 years from the canton Ticino, in the south of Switzerland, was analysed. The pre-Alpine to Alpine setting, combined with a mild temperate climate makes for a large number of natural events per year. The inventory consists of entries for spatially located movement types corresponding to rockfalls (43 %), debris flows (28%), landslides (17%), and avalanches (12%), with some recorded variables (date, coordinates, etc.). Additional geometrical data, as well as data from four categories (topography, hydrography, land use, and geology) was collected and pre-processed. Both a simple analysis and a more complex ones were carried out. From the initial statistical analysis, we determined that the relevant controlling parameters in this context are slope, aspect, terrain roughness index, topographic wetness index, and general lithology; while geometrical aspects of importance are area, length, height difference, volume, and angle of reach. We also conclude that the most affected districts are those of Blenio, Mendrisio, Locarno and Bellinzona, where debris flows and avalanches, debris flows, rockfalls and rockfalls prevail, respectively. From the geometrical aspects, we conclude that that rockfalls and landslides tend to have smaller areas and perimeters than avalanches and debris flows, as expected, due to their mobility. However, the deposit lengths, height differences and volumes show similar patterns. The calculated angle of reach shows similar median and mode values at around 26º/30º, 33º, 34º/35º and 41º, for debris flows, avalanches, landslides, and rockfalls and respectively. Significant power law correlations were found between deposit length and the height difference (cf. Corominas, 1996), deposit volume and the movement area (cf. Guzzeti et al., 2009), and the distribution of rockfall volumes (cf. Dussauge et al., 2003). Possible further work with this inventory includes probabilistic approaches and the application of machine learning techniques for the establishment of the precise relationships between the different controlling parameters and each movement type.

 

References

Corominas, J. (1996). The angle of reach as a mobility index for small and large landslides. Canadian Geotechnical Journal, 33(2), 260-271.

Dussauge, C., Grasso, J. R., & Helmstetter, A. (2003). Statistical analysis of rockfall volume distributions: Implications for rockfall dynamics. Journal of Geophysical Research: Solid Earth, 108(B6).

Guzzetti, F., Ardizzone, F., Cardinali, M., Rossi, M., & Valigi, D. (2009). Landslide volumes and landslide mobilization rates in Umbria, central Italy. Earth and Planetary Science Letters, 279(3-4), 222-229.
A range of different negative leader propagation modes as imaged with LOFAR
Authors: Scholten Olaf , Hare Brian , Dwyer Joe , Liu Ningyu , Sterpka Chris , Buitink Stijn , ter Veen Sander
Published: March 2022

We have developed a time-resolved interferometric imaging in 3D (TRI-D) method for LOFAR data where the signals of 400 individual antennas are added coherently. This allows us to reach an even better resolution in 3D than with our original impulsive imager (based on a time-of-arrival-difference method and reaching a meter scale resolution) and still have a time resolution close to the impulse-response time of our system (25 ns).

After a short outline of the TRI-D technique we show that with this new imaging technique we can resolve the fine dynamics in the different negative leader propagations modes, varying from normal negative leaders with a stepping distance of the order of a few tens of meters to negative leaders at altitudes above 7 km that propagate with steps of a few hundred meter to Intensely Radiating Negative Leaders that propagate as a broad front with an area of up to km^2  over distances of a few kilometers.  
Determination of continuous discharge time series based on the optical Particle Tracking Velocity (PTV)
Authors: Kutscher André , Grundmann Jens , Eltner Anette , Blanch Xabier , Hedel Ralf
Published: March 2022

The importance of optical measurement methods in hydrology is increasing in the last years. In contrast to conventional gauging techniques, they can be applied remotely, making the measurement safe for humans and equipment, even under difficult measurement conditions. One important hydrological parameter to measure is discharge. Deriving discharge with remote sensing can be done by applying particle tracking velocimetry (PTV) in combination with the velocity area method (VAM). VAM is a standardized and established method in hydrology. For reliable discharge results with the VAM, surface flow velocity measurements and thus trackable particles in the case of PTV usage are required across the entire width of the river cross section, which is not always the case in natural observation conditions. To fill these data gaps several statistical methods were investigated that incorporate information provided at different measurement times but with similar discharge conditions.

In this study, data were collected over longer time periods with different cameras at a gauging station of a medium scale river in Saxony, Germany. Stationary cameras recorded short videos, which are used to estimate the velocity distribution at the water surface using PTV incorporated in the FlowVelo tool (Eltner, 2020), and afterwards, to estimate the discharge using VAM. The obtained discharge time series from different cameras and camera positions were used to analyse the performance of different gap filling approaches. The results were compared to discharge and water level measurements of the official gauging station maintained by the federal measuring agency. They show, that the adjustment to the data of the reference measurements increases significantly by application of the gap filling methods. Next steps are to enhance the presented methods by using targeted data filtering and deep learning.

Keywords: velocity area method, particle tracking velocimetry, camera based discharge estimation
Ascending smoke vortices in the stratosphere
Authors: Legras Bernard , Podglajen Aurélien , Sellitto Pasquale , Lestrelin Hugo , Reboud Jehanne , Doc Josselin , Lapeyre Guillaume
Published: March 2022

Ascending persistent smoke mesoscale anticyclonic vortices have been recently discovered in the mid-latitude stratosphere after several large wildfires. Such vortices can survive up to three months are rising to top altitudes between 20 and 36 km distributing aerosols along their way. They are also associated with a mini ozone hole.  We will survey these observations from active and passive satellite instruments and the reconstruction of vortices by assimilation of the signature left in the ozone and temperature measurements. We will show in particular how the temperature dipole associated with the vortices is retrieved from the GPS-RO occultation and reproduced by the assimilation and describe a remarkable case of superimposition during the crossing of two vortices.  

We will then describe our current understanding of the dynamics and stability of such structures where the radiative heating by solar absorption on the black carbon is the key forcing and where long wave radiative transfer provide a damping and diffusive effect. We will discuss the similarities and differences between simulations representing and full dynamics and the analysis that relies only on the  temperature information. A simplified 1D-model will be used as a tool for interpretation and sensitivity studies.
Water planet thresholds: The topographic scope for land atop a stagnant lid
Authors: Guimond Claire Marie , Rudge John , Shorttle Oliver
Published: March 2022

Small water budgets produce desert worlds and large water budgets produce water worlds, but there is a narrow range of water budgets that would grant a marbled surface to a rocky planet. A planet’s highest point can constrain this range in that it defines the minimum ocean volume to flood all land. Thus we take a first step in quantifying water world limits by estimating how minimum surface elevation differences scale with planetary bulk properties. Our model does not require the presence of plate tectonics, an assumption which has constricted the scope of previous studies on exoplanet land fractions. We focus on the amplitudes of dynamic topography created by rising and sinking mantle plumes—obtained directly from models of mantle convection—but also explore rough limits to topography by other means. Rocky planets several times more massive than Earth can support much less topographic variation due to their stronger surface gravity and hotter interiors; these planets’ increased surface area is not enough to make up for low topography, so ocean basin capacities decrease with planet mass. In cooler interior thermal states, dynamically-supported topography alone could maintain subaerial land on Earth-size stagnant lid planets with surface water inventories of up to approximately 100 ppm of their mass (or half Earth’s ocean mass fraction). Considering the overall cap to topography on such planets would raise this threshold ocean mass fraction by an order of magnitude. Current estimates of the surface water contents on TRAPPIST-1e to g place these planets near or above the ultimate topographic waterworld threshold, depending on their core masses.
Quartz grain fabric in shales and sandstones: Some contrasting behaviors 
Authors: Aubourg Charles , Saur Hugo , Moonen Peter , Stokes Rebecca
Published: March 2022

Many processes are at work when a sedimentary rock deforms. Quartz grains, for example, can rotate rigidly in the matrix, or on the contrary, undergo processes of dissolution and crystallization. Microtomography allows us to image the 3D geometry of minerals at the micron scale and quantify their fabric. Here, we use the quartz shape fabric extracted from microtomography data to evaluate the mechanisms active during burial and deformation of several sedimentary rocks systems.

Our first examples are of shales developing a slaty cleavage oblique to bedding. For shales that have undergone moderate burial (Tburial max ~200°C) (Sigues locality, Pyrenees), we show that the quartz grains rotate very little in the clay matrix. Even with the development of a slaty cleavage, a significant proportion of quartz grains remain parallel to the bedding plane. This surprising result implies that the rigid rotation of quartz grains, even in a ductile clay matrix, is not effective. 

In shales having undergone deeper burial and temperatures approaching the lower greenschist facies (Tburial max ~280°C) (Lehigh Gap locality, Appalachian mountains), we show that the average short-axis of the grains is orthogonal to the cleavage plane.  We suggest that this shape preferred orientation results from preferential dissolution of quartz faces oriented perpendicular to sigma 1, thus resulting in a shape preferred orientation without significant grain rotation.

Our last example concerns fine-grained sandstones, slightly deformed and buried at a shallow depth. If we refer to the example of shales with little burial, we would expect a very strong control of the bedding on the quartz fabric, since at these P-T conditions we expected dissolution-precipitation processes to be sluggish, and grain rotation to be ineffective.  However, surprisingly, the quartz in this rock is well oriented in the fabric which is oriented perpendicular to the bedding.

How the quartz grains were reoriented in the fine-grained sandstone suggests relations still not well understood with the deformation of a porous rock and the cementing processes of the rock. The microtomography approach in fine-grained rocks opens a door to this understanding of the behavior of quartz grains in sedimentary rocks.
Preferential Acceleration of Suprathermal Particles at Shocks
Authors: Livi Stefano , Owen Chris , Louarn Philippe , Fedorov Andrei , Alterman Ben , Lepri Susan , Raines Jim , Galvin Antoniette , Kistler Lynn , Allegrini Frederic , Ogasawara Keiichi , Wurz Peter , Bruno Roberto , D'Amicis Raffaella , Collier Michael
Published: March 2022

On October/November 2021 the Heavy Ion Sensor onboard Solar Orbiter observed data connected to three interplanetary shock events: Oct 30, Nov 3 and Nov 27. During all three events, the flux of suprathermal particles, defined as those having an energy larger than twice the energy of the solar wind component, showed remarkable intensification. We discuss those changes and specifically how particles of different mass/charge and energy/charge distribution before the shock are affected differently by the interaction with the shock front itself. From these three expampes, it appears that intensifications are stronger for species already having a seed population in the suprathermal regime.
The new emerging DOI biotope within and around the Open Source Geospatial Foundation (OSGeo)
Authors: Löwe Peter , Nartišs Maris , McKenna Jeff , Emde Astrid
Published: March 2022

We report on the adoption of persistent identifiers by community-driven geospatial open source communities and their umbrella organisation OSGeo. After a ramp up process, which included the introduction and evaluation of Digital Object Identifiers (DOI) for OSGeo conference recordings, a growing number of OSGeo project communities have started to adopt DOI for their respective code bases (e.g. MOSS GIS https://doi.org/10.5281/zenodo.5825144, GRASS GIS https://doi.org/10.5281/zenodo.5810537), enabling scientific reference and citation for distinct versions of code and also the overall software project code base. In addition, the use of persistent IDs for persons is accelerating. This presentation provides an overview over the latest state of DOI use by projects, lessons learned, emerging challenges (e.g. DOI-based reference for software versions predating the DOI minting) and emerging opportunities for the OSGeo communities (e.g. integration of DOI for code, presentations, manuals and video) and beyond.
Methylmercury in thawing peatlands on a trophic gradient in boreal Western Canada
Authors: Thompson Lauren , Shewan Renae , Harris Lorna , Mangal Vaughn , Olefeldt David
Published: March 2022

Ongoing permafrost thaw in the extensive peatlands of boreal western Canada may mobilize previously frozen mercury (Hg) and result in enhanced production of the neurotoxin methylmercury (MeHg). The often waterlogged conditions in thermokarst wetlands may represent ideal environments for Hg methylation to MeHg, but methylation potential could vary across distinct wetland types (i.e., nutrient-poor bogs and nutrient-rich fens) that emerge after the thawing of drier peat plateaus, depending on landscape position and groundwater connectivity. Here, we examined MeHg concentrations in twelve wetlands of varying nutrient richness in the Taiga Plains of western Canada across a 500 km permafrost gradient. We analyzed peat porewater chemistry (Hg, MeHg, dissolved organic matter composition), inferred the degree of groundwater connection (electrical conductivity, ions), and assessed the vegetation composition at each wetland. The key research objectives of this study were to 1) determine how methylmercury concentrations vary amongst wetland types in the Taiga Plains and amongst permafrost zones, and 2) understand how physicochemical characteristics and groundwater connectivity may influence methylation potential. Through this, we hope to understand the factors that lead to hotspots of MeHg production in the rapidly thawing peatlands of the Taiga Plains.
Differences in the increase of frequency and intensity of extreme precipitation between models and scales over Europe
Authors: Steensen Birthe , Myhre Gunnar , Hodnebrog Øivind , Altherskjær Kari
Published: March 2022

The frequency and intensity of heavy and extreme precipitation events in Europe have increased since the 1950s. Earlier studies have found, using observational datasets, that frequency increases more than intensity and that both increase more with event rareness. Here we compare changes in intensity and frequency for different observational and model datasets. Both CMIP6 global models with ensembles and regionally downscaled model results are analyzed. The regional models (from CORDEX) are driven by both reanalysis and CMIP5 models. Data are analyzed over two 30-year periods from 1951 to 1980 and 1981 to 2010. Results show that the models do not manage to produce the same increase in frequency as observed, however results are more similar for intensity increase. There are large differences in the change in extreme precipitation in model ensembles. The probability density functions for each of the observational and model datasets show that there are differences in the pattern of the shift between the two time periods.