bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of fast preferential flow distribution in a complex snow-governed karst system based on an inference of secondary faults, doline distribution, and tracer tests experiments: An application to Mount Lebanon  
Authors: Doummar Joanna , Almendral Vazquez Ariel
Published: March 2022

Six tracer experiments were undertaken under different flow periods to delineate the catchment area and identify transport parameters in two snow-governed springs Laban and Assal in Mount Lebanon used for water supply. The two springs yield different responses to snow melt, ambient temperature in high flow and in recession despite their common origin from the same Albian-Cenomanian rock sequence. These discrepencies were attributed partly to different facies within the aquifer (limestone and dolostones). Yet faults and secondary fractures also play an important role in defining preferential flows in such a complex system. Secondary faults and fractures are difficult to depict in the field and were assessed via fracture analysis. In this work, primary faults with their characteristics (displacement and trends) are input in a Havana software (developed by Norsk Regnesentral; SAND 2021) based on field data used to simulate new faults. The model generates a secondary set of faults from a truncated fractal distribution, yielding thus different realizations of the set of secondary faults depending on the parametrization of the fractal model. The realizations will be validated with field data, doline distribution, and fracture analysis as well as tracer experiments results. This work allows to combine physical data with geostatistical techniques to optimize the delineation of the catchment and preferential flow in complex vulnerable karst systems.
Evidence of acceleration in sea-level rise for the North Sea
Authors: Riva Riccardo , Steffelbauer David , Timmermans Jos , Kwakkel Jan , Bakker Mark
Published: March 2022

Global mean sea-level rise (SLR) has accelerated since 1900 from less than 2 mm/year during most of the century to more than 3 mm/year since 1993. At the regional scale, detection of an acceleration in SLR is difficult, because the long-term sea-level signal is obscured by large inter-annual variations with multi-year trends that are easily one order of magnitude larger than global mean values. Here, we developed a time series approach to determine whether regional SLR is accelerating based on tide gauge data. We applied the approach to eight 100-year records in the southern North Sea and detected, for the first time, a common breakpoint in the early 1990s. The mean SLR rate at the eight stations increases from 1.7±0.3 mm/year before the breakpoint to 2.7±0.4 mm/year after the breakpoint (95% confidence interval), which is unprecedented in the regional instrumental record. These findings are robust provided that the record starts before 1970 and ends after 2015.
How does environmental context influence the leaf phenology of tree species in Maritime Canada?
Authors: Spafford Lynsay , MacDougall Andrew H.
Published: March 2022

Hemiboreal forest encompasses the shifting optimal distribution limits of both boreal and temperate forest types, providing an opportunity to develop insights for the potential effects of global change on each forest type. Leaf phenology, the timing of leaf life cycle events, serves as a dynamic indicator of biological response to climate change and signifies the potential robustness or susceptibility of particular species to future change. In order to better understand how environmental context influences the leaf phenology of hemiboreal tree species we installed a network of 34 leaf phenocam stations across Maritime Canada encompassing a range of 3° latitude and 2 °C in annual average temperatures. The most common broadleaf species observed were red maple (Acer rubrum) and paper birch (Betula papyrifera), while the most common needleleaf species we observed were red spruce (Picea rubens) and balsam fir (Abies balsamea). Our phenocam stations consist of a solar-powered consumer grade cellular time-lapse camera and colour reference panel, and were installed prior to and throughout the 2019, 2020, and 2021 growing seasons. We dissected image field of views into regions of interest corresponding to discernable individuals and used green chromatic coordinate curve fitting and threshold extraction approaches. We found that most species had a high degree of plasticity in phenological response to varying site conditions, though some had a conserved response to varying site conditions relative to other species. We also observed an unusually early fall green-down for paper birch at one site in July of 2021. This suggests that climate change may have differential effects on hemiboreal tree species due to phenology triggers being distinct among species. This work demonstrates the complexity of environmental influence upon leaf phenology, as well as the utility of phenocams in monitoring leaf phenology in remote regions of Maritime Canada.
Nitrogen transport and retention dynamics across central European catchments using large-sample data
Authors: Nguyen Tam , Fleckenstein Jan , Saraazin Fanny , Ebeling Pia , Lutz Stefanie , Musolff Andreas , Kumar Rohini
Published: March 2022

Human activities, especially agricultural practices, have significantly altered the Earth’s landscape and the global cycle of nitrogen. In Europe, diffuse nitrogen (N) input from agriculture has been identified as a major driver of marine eutrophication. Despite a long history of measures, little improvement in groundwater and surface water quality has been observed. Recent studies have attempted to provide insights into nitrogen dynamics at the catchment scale, helping to explain the causes and effects of persistent water quality problems. However, there is a lack of large-scale, long-term studies that provide insights into both biogeochemical and hydrological N legacies under different landscape settings. Here using data of more than 100 German catchments of the last seven decades, we synthesis the nitrogen transport and retention dynamics, as well as their dominant (landscape and climate) controls in a large-sample setting. To this end, we adapted the mHM-SAS model (Nguyen et al., 2021) to reflect regional-scale biogeochemical and hydrological N legacies, taking into account the historical development of both diffuse and point sources. The underlying parameterizations were constrained using instream N concentrations. We found high heterogeneity in catchment responses to N inputs. The fractions of N surplus that were stored in the soil, removed by denitrification, stored in the subsurface, and finally exported to the stream vary over a wide range. Our analysis of the long-term (1950-2014) average N balances from all catchments suggests that a majority (mean = 57%) of N surplus was removed by denitrification, followed by stream N export (27%) and the rest was stored in the catchment (16%). Despite the reduction in N surplus after 1990s, biogeochemical legacy reflected in the soil N build-up showed an increasing trend over the analyzed period (1950-2014) across a majority of the study catchments. As for the hydrologic legacy, we found a varying range of mean transit times of discharge between 3.5 years and 13.1 years (95% confidence interval) among the analyzed catchments. Overall, our large-sample analysis provides a detailed overview of biogeochemical and hydrological N legacies across Germany; and thus provides useful insights for an improvement of agricultural practices and water quality management in Central European landscapes.

Nguyen, V.T., Kumar, R., Musolff, A., Lutz, S. R., Sarrazin, F., Attinger, S., & Fleckenstein, J. (2021 WRR - in revision). Disparate Seasonal Nitrate Export from Nested Heterogeneous Subcatchments Revealed with StorAge Selection Functions. https://doi.org/10.1002/essoar.10507516.1
A Stochastic Rainfall Generator Suitable for Modeling Future Compound Disasters Associated with Heavy Rainfall
Authors: Kim Dongkyun , Onof Christain , Park Jeongha , Wang Lipen
Published: March 2022

Disasters associated with heavy rainfall such as urban floods, riverine floods, and landslides often simultaneously occur while each of them sensitively reacts to rainfall variabilities at distinct ranges of time scales. Therefore, a stochastic rainfall model suitable for modeling compounding of disasters must be good at reproducing the rainfall variability across all timescales relevant to all types of disasters. This study proposes a point stochastic rainfall generator that can reproduce various rainfall characteristics at timescales between 5 minutes and one decade. The model generates the fine-scale rainfall time series using a randomized Bartlett-Lewis Rectangular Pulse (RBLRP) model. Then the rainstorms are shuffled such that the correlation structure between the consecutive storms is preserved. Finally, the time series is rearranged again at the monthly timescale based on the result of the separate coarse-scale monthly rainfall model. The method was tested using the 69 years of 5-minute rainfall data recorded at Bochum, Germany. The mean, variance, covariance, skewness, and rainfall intermittency were well reproduced at the timescales from 5 minutes to a decade without any systematic bias. The extreme values were also well reproduced at timescales from 5 minutes to 3 days. The past-7-day rainfall before an extreme rainfall event, which is highly associated with the extreme riverine flow and landslide was reproduced well too. Then, the model was extended to integrate the influence of climate change. For this, the model was re-parameterised in terms of parameters representing average magnitude and temporal structure of the rainfall time series. Then, the relationship between these new parameters and the covariates (e.g. monthly, weekly, daily temperature) were investigated. Lastly, the derived regression relationships were applied to adjust the duration and the magnitude of rain storms and cells that were generated by the stationary RBLRP model.
High-Resolution Ensemble Precipitation for Pluvial Flood Forecasting in the Urban Data Scarce city of Alexandria, Egypt 
Authors: Young Adele , Bhattacharya Biswa , Mahood Faisal , Daniels Emma , Zevenbergen Chris
Published: March 2022

High-resolution Quantitative Precipitation Forecasts (QPF)  are essential to accurately forecast the magnitude, timing and location of precipitation and as input for pluvial flood forecasting using urban drainage models. However, there are challenges of producing high-resolution forecast capable of capturing the spatial and temporal variability of rainfall needed for urban flood modelling and the uncertainty associated with meteorological forecast and urban flood models. Therefore there is a challenge to balance data availability, model uncertainty, resolution, forecast lead-time and computational demands, especially in data-scarce regions.

Ensemble precipitation forecasts are used to capture uncertainties of meteorological forecasting in flood models. This research aims to evaluate the skill of a downscaled ensemble precipitation forecast over the coastal city of Alexandria, Egypt which experiences extreme rainfall and flooding from winter storms. A Weather Research Forecast (WRF) convection-permitting model was initialised using the Global Ensemble Forecast System (GEFS) which provides 21 ensemble members (1 degree archived). The model was run using three domains with horizontal grid resolutions of 30km, 10 km and 3.3 km at a 24h leadtime). For the 3.3 km horizontal grid, ensemble members were coupled with a 1D Mike urban model to evaluate the meteorological uncertainty representation and propagation.

In the absence of sufficient rainfall and flow gauge data, results were verified against Multi-Source Weighted-Ensemble Precipitation (MSWEP) satellite-derived product and further compared with the ECMWF ensemble prediction system precipitation forecast. 1D flood simulations were evaluated against 1D- 2D hydrodynamic simulations run with MSWEP data.

Ensembles showed varying probability of detection for different severity events. In general, the majority of ensemble rainfall values resulted in flooding greater than the flooding simulated from the satellite observed rainfall. Although deterministic forecast also indicated flooding and threshold exceedance, the number of ensemble members exceeding critical thresholds has the benefit of providing decision-makers with the probability of threshold exceedance and likelihood of flooding to trigger protective actions. A study such as this provides knowledge for understanding, future applications and limitations of using high-resolution ensemble Quantitative Precipitation Forecasts (QPFs) and the importance of capturing the spatial and temporal variability of rainfall in urban drainage models. Additionally, the potential use of MSWEP for the verification of ensemble forecasts in ungauged and data-scarce regions is investigated.
Towards a collaborative governance regime for disaster risk reduction: exploring scalar narratives of institutional change in Nepal.
Authors: Russell Caroline , Clark Julian , Hannah David , Sugden Fraser
Published: March 2022

This paper contributes to the study of collaborative governance (CG) - systems where autonomous actors work together around shared objectives using pooled resources to address a common goal. Among CG’s claimed benefits are boosting actor capacities for transformative action and increasing their resilience to complex multi-scaled challenges such as hazards and sudden catastrophic events. We engage with collaborative governance through a case study of changing public policy and institutional structures that govern hazards in Nepal. Following the shocking event of the 2015 Gorkha earthquake, Nepal’s approach to disaster risk reduction (DRR) has been reshaped by federalisation and institutional reforms that aim to embed a governing system based on greater collaboration. We argue this shift amounts to a state transition to a collaborative governance regime (CGR) for DRR. Using primary qualitative data derived from 17 semi-structured interviews at national, provincial, and local scales, we identify state-sponsored scalar narratives around 1) actor capacities and tendencies in DRR; 2) knowledge production on DRR and its dissemination; and 3) formal and informal institutional DRR roles and responsibilities. We show how these narratives are being used as anchor points for a new CG approach to national DRR strategy. However, our analysis shows these narratives risk excluding local participation in DRR by marginalising grassroots politics to emphasise top-down state-led goals. In turn, this leads us to question the viability of the emerging governance regime as a truly collaborative project embedding principles of sustainability and inclusivity. We conclude that if these state scalar narratives continue to shape national policy, they will impede the potential for transformative collaborative action for DRR in Nepal.
Added Value of a Convection Permitting Model in Simulating Atmospheric Water Cycle Over the Asian Water Tower
Authors: zhao yin
Published: March 2022

The Tibetan Plateau (TP) is known as Asian Water Tower and its atmospheric water cycle has been a lasting challenge to climate modeling community. Here, we compare two sets of the Met Office Unified Model simulations—one is a convection-parameterized version (large-scale model; LSM) and the other is a convection-permitting model (CPM) simulation. The added value of the CPM in terms of atmospheric water cycle process is analyzed, including external moisture transport, fraction of atmospheric water vapor converting to precipitation and the precipitation recycle ratio. Results show that the simulated TP precipitation and evaporation for the summer of 2009 is significantly improved in the CPM. First, the overestimation of atmospheric water cycle by LSM is improved in CPM due to a reasonable representation of the fraction of atmospheric water vapor converting to precipitation. The overestimation of precipitation recycle ratio also indicates the LSM generates excessive convection compared to the CPM and therefore has a larger wet bias over the TP. Second, a better simulation of local precipitation has feedback on the circulation. Compared with the LSM, the less moisture convergence in the CPM is dominated by the stronger outflow through the eastern edge of the TP rather than the weaker inflow, implying the upscale effects of the resolved moist convection on the moisture transport over the TP. Our results imply that the CPM is a useful tool in the reproduction of moisture transport and atmospheric water cycle process over the Asian Water Tower and other regions of the world with complex topography.
Influence of offshore wind farms on the latent heat flux in the marine boundary layer
Authors: Platis Andreas , Büchau Yann , Bange Jens
Published: March 2022

Unique airborne in-situ measurements were evaluated to investigate the influence of offshore wind farms on the latent heat flux in the marine boundary layer. 21 of the total 42 measurement flights carried out in the frame work of the WIPAFF project over the German Bight in the years 2016 and 2017  enabled such an evaluation under different atmospheric conditions. The measurements of 15 flights showed a significant increase of the vertical upward latent heat flux over the offshore wind farm clusters Amrumbank West, Nordsee Ost, Meerwind Süd/Ost or the wind farm Godewind. Under thermally stable conditions, all except one of the measurement flights showed an increase of latent heat flux over or in the wake of the wind farms, with an heat flux up to 17 times higher compared to the undisturbed flow. During flights under unstable thermal stratification, the phenomenon was observed in 8 out of 13 cases. The results also suggest that not only thermal stratification but also moisture stratification plays a decisive role in whether the influence of the wind farm becomes noticeable in the latent heat flux.  Considering the absolute amount of the increase of the upward latent heat flux, a maximum increase of +400 W/m² was measured in unstable conditions. 
The climate in climate economics
Authors: Folini Doris , Kübler Felix , Malova Aleksandra , Scheidegger Simon
Published: March 2022

We develop a generic and transparent calibration strategy for simple climate models used in economics. The goal is to choose the free model parameters such as to best match the output of large-scale Earth System Models from the Coupled Model Intercomparison Project, run on pre-defined emissions scenarios. We propose to jointly use four different test cases that are considered pivotal in the climate science literature: two highly idealized tests to separately examine the carbon cycle and the temperature response, and two tests closer to real scenarios, incorporating gradual changes in CO2 emissions and exogenous forcings.

To illustrate the applicability of our method, we re-calibrate the free parameters of the climate part of the seminal DICE-2016 model for three different CMIP5 model responses: the multi-model mean as well as two CMIP5 models that exhibit extreme but still permissible equilibrium climate sensitivities. As an additional novelty, our calibrations of DICE-2016 allow for an arbitrary time step in the model explicitly. By applying our comprehensive suite of tests, we i) confirm that both the temperature equations and the carbon cycle in DICE-2016 are miscalibrated and ii) we show that by re-calibrating coefficients all CMIP5 targets considered can be well matched.

Finally, we apply the economic model from DICE-2016 in combination with the newly calibrated climate model to compute the social cost of carbon and optimal warming. We find the social cost of carbon to be similar to DICE-2016, while the optimal long-run temperature is almost one degree lower.  The social cost of carbon turns out to be much less sensitive to the discount rate than in DICE-2016. We explain how the model's climate part relates to these differences. As the temperature in DICE-2016 under optimal mitigation falls outside the range of CMIP5 projections, we caution that one might want to be skeptical about policy advice based on DICE-2016.
Relationship between temporal variation of Earth's flattening and spatial distribution of global earthquake energy
Authors: Fodor Csilla , Varga Péter
Published: March 2022

The secular change in the flattening of Earth and its effect on global tectonics is a subject still to be investigated.

Tidal friction causes a constant despinning of the rotation of Earth. It happens at a rate of Δω = – (5.4 ± 0.5) ∙ 10-22s-2, resulting in a change of the length of day with ∆LOD = (2.3 ± 0.1) ms/century (Stacey, 1992). The slowly decreasing rotational speed creates a change in the flattening of the Earth, that produces a latitude dependent stress field. The meridional stress component is always positive (i.e. tensional), while the azimuthal stress is negative (i.e. compressional) from the equator, up to the critical latitudes (~ ±48.2°), and positive poleward. This means two major tectonic provinces: in the equatorial region a strike-slip province and towards the poles, a normal fault province (Denis & Varga, 1990).

From the 1960s reliable seismological catalogues are available. ISC GEM Catalogue contains re-computed moment magnitude (Mw) values, what is essential for calculating the released seismic energy, since at higher magnitudes, it doesn’t go into saturation. One can obtain the energy released by an event with the formula logE = 5.2 + 1.44Mw (Båth, 1966). Based on this catalogue, a 52-year period with moment magnitudes higher than 5.8, all in all 8799 events were used.

Our study shows that the effect of the despun Earth is reflected in the latitudinal distribution of earthquake energy, which is symmetric with respect to the equator and there are clear maxima at mid-latitudes. The distribution of seismic energy released by either normal fault or strike-slip earthquakes also follow a pattern previously described. Especially on the northern hemisphere normal fault events occur dominantly towards the poles while strike-slip earthquakes tend to happen at lower latitudes. We can conclude that tidal friction actually creates the proposed stress field on Earth, and is visible if we observe how global seismicity behaves with respect to latitude.

 

Båth, M. (1966). Earthquake energy and magnitude. Physics and Chemistry of the Earth, 7, 115-165.

Denis, C., Varga, P. (1990). Tectonic consequences of the Earth’s variable rotation, In: Brosche P, Sündermann J (eds.) Earth rotation from eons to days. Springer, pp. 146-162.

Stacey, F. D. (1992). Physics of the Earth, Brookfield Press, Australia, ISBN 0-646-09091-7.
Participatory Digital Earth Twin Hydrology systems (DARTHs) for everyone: a blueprint for hydrologists 
Authors: Rigon Riccardo , Formetta Giuseppe , Bancheri Marialaura , Tubini Niccolò , D'Amato Concetta , David Olaf , Massari Christian
Published: March 2022

The Digital Earth (DE) metaphor is very useful for both end users and for hydrological modellers. However, in literature it can promote the erroneous view of models as a commodity, that is a basic good used in commerce that is interchangeable with other goods of the same type, without any warning about the fact that some models work better than others, some models just work while others can be simply wrong. These distinctions are at the core of doing good science. This opinion contribution, on the one hand, tries to accept the challenge of adopting models as commodities but, on the other, it wants to show that this acceptance comes with some consequences as to how models must be structured.  The first reuirement is that Digital eARth Twin Hydrology system (called DARTH) need to be Open Source and built with Open Science rules in mind. We analyse different categories of models, with the view of making them part of a . We also stress the idea that DARTHs are not models in and of themselves, rather they need to be built on an appropriate infrastructure that provides some basic services for connection to input data and allows for a modelling-by-components strategy, which, we  argue, is the right one for accomplishing the requirements of the DE. The need to tie predictions to an estimated confidence interval is also supported. Finally, it is argued that DARTHs must promote a new participatory way of doing hydrological science, where researchers can contribute cooperatively to characterize and control model outcomes in various territories. Furthermore, this has consequences for the engineering of the systems. 

 
Seasonal dynamic of marls sediments illustrated by field records on hillslopes properties, Draix-Bléone CZO, SE France.
Authors: Ariagno Coline , Le Bouteiller Caroline , van der Beek Peter
Published: March 2022

Sparsely vegetated, badlands are loci of intense erosion that is sufficiently rapid to have observable effects on human timescales and is partly controlled by climate. Characterizing and understanding the physical weathering processes in these areas are key to predict the temporal variability of regolith production and sediment flux, as well as their evolution under changing climate conditions.

Here, we study intra-annual changes of hillslopes properties and explore the relationship between production and transport of sediments in steep marly badland catchments of the Draix-Bléone Critical Zone Observatory (SE France), where decades-long monitoring records show rapid morphologic changes. Remote-sensing imagery has recorded the seasonal dynamics of these badlands, but characterization and quantification of physical weathering processes have been lacking up to now. We explore this gap by monitoring key regolith parameters including grain size distribution (GSD), surface resistance, and water content in the regolith layer (surface to ∼10 cm depth) at different locations, through repeated field surveys over a 2-year period. While water content appears to be directly controlled by the last previous rainfall event, GSD and resistance show a similar cyclic annual pattern, with a maximum at the end of summer and a minimum during winter. Principal component analysis (PCA) highlights the strong correlation between resistivity and GSD (characterized by D50). However, resistance is also partly controlled by water content. We therefore suggest that D50 provides the best proxy of regolith weathering in these marls; this is supported by vertical GSD profiles that show an exponential decrease of D50 toward the surface, resembling the theoretical profile of weathering intensity (e.g., Heimsath et al., Nature, 1997). The cyclic annual pattern in observed D50 suggests that loose and finaly fragmented regolith is mainly produced and accumulates during the winter season, whereas sediment transport is dominant during spring-autumn, reducing regolith thickness and inducing a coarsening of hillslope surface material. These observations thus support a model in which frost-cracking is the main process controlling sediment production in these catchments (Ariagno et al., ESurf, 2022). These results also corroborate the strong annual dynamics of these catchments, where hillslopes and gullies are drained during spring and early summer high-intensity precipitation events, inducing high sediment yields.

We use these quantitative observations to develop and calibrate a landscape-evolution model at (sub-) annual timescales. We aim to use this model to (1) reproduce sediment dynamics in badland catchments and (2) improve predictive models of sediment export from such catchments under a changing climate.
Distribution of pathogens and antibiotic resistance genes in the vadose zone of soil-aquifer treatment (SAT) system.
Authors: Yadav Niraj , Ronen Zeev , Arye Gilboa
Published: March 2022

The main objective of this study was to quantify the distribution of pathogens and antibiotic resistance genes in the vadose zone of the soil aquifer treatment (SAT) system. Soil samples were collected from a treated wastewater infiltration basin to a depth of 25 m in two sampling events: (i) at the end of flooding and infiltration and (ii) following three days of drying before the subsequent flooding event. Viable count parallelly of bacteria compared with microscopic live/dead count and enzymatic activity FDA hydrolysis. The abundance of the total bacteria, coliform, antibiotic resistance bacteria (ARB), were examined.  In addition, total genomic DNA was extracted from soil samples (n-28 for both flooding and drying cycle), and quantitative PCR (qPCR) was used to determine the relative abundance of antimicrobial resistance genes (ARGs), including 1 integron-integrase intI1, blaTEM, blaCTX-M-32, sul1, qnrS.

In both sampling events, the results demonstrate that the distribution of antibiotic resistance genes in the vadose zone exhibits a similar pattern to the one obtained for the examined pathogen. We observed a high concentration of pathogens in topsoil layers and a gradual decline with depth. In this presentation, the profile obtained will be described and discussed with pathogens and ARGs transport and retention in the SAT system. 

 

 
Constraining transformation weakening in plagioclase-pyroxene mixtures
Authors: Lee Amicia , Stünitz Holger , Soret Mathieu , Précigout Jacques
Published: March 2022

Mafic rocks are a key constituent of the oceanic and lower continental crust. Strain localisation and fabric development in these rocks is controlled by the active deformation mechanisms. From studies of natural rocks it has been established that strain localisation and weakening in mafic rocks is directly related to fluid availability and resultant mineral reactions. Understanding the interplay between reactions, fluid availability, and deformation aids in quantifying the stresses and rates of deformation processes. We have conducted an experimental investigation to constrain the weakening mechanisms in gabbro. Shear experiments were performed in a Griggs-type apparatus at 800-900°C, and 1.2-1.5 GPa with a shear strain rate of 10⁻⁵s⁻¹. The starting material consists of mixed powders with <100 µm sized grains of plagioclase and clinopyroxene from an undeformed sample of the Kågen Gabbro in Northern Norway. Experiments have been conducted with ‘as is’ (dried at 110°C) starting material and with 0.1% added water. The experiments at 800°C are very strong with a peak shear stress ~0.8 GPa whilst the 900°C experiments are weaker, reaching peak stresses of ~0.35 GPa. The 800°C experiments show evidence of mineral reactions with newly formed phases making up 10-25% of the sample. In these reaction zones, plagioclase and clinopyroxene have reacted to produce amphibole and garnet. Additionally S-C’ mylonitic fabrics have developed in these samples. The 900°C samples show minimal evidence for mineral reactions (2-5% new material) or crystal-plastic deformation mechanisms. The lack of mineral reactions in the rheologically weak experiments (900°C) and abundance of reaction products in the mechanically strong experiments (800°C) is conflicting to our inferences of natural studies. However, if partial melting takes place in the higher temperature experiments, it may account for the pronounced strength decrease. We plan to conduct EBSD and TEM analysis to determine crystallographic properties and accurate grain size and shape parameters in the fine grained reaction zones. Future experiments will use fully dried natural starting material (dried at 700-800°C) and An60 and end-member diopside, these experiments will be compared with our current experiments and be used to determine the exact weakening properties from impurities in the natural starting material.
Large-scale spatial reconstitution of pressure and tracer tests responses in a karst aquifer (Lez aquifer, France)
Authors: Fischer Pierre , Jourde Hervé , Leonardi Véronique
Published: March 2022

Spatial characterization of the hydraulic properties in the subsurface is an extensively studied problematic. Inverse problems allow to image those properties by interpreting the information from a dataset of field measurements with a chosen physical formulation of fluxes in a numerical distributed model. However, karst media characterization remains a complex task, due to the fact that the matrix and conduits entities generate a highly contrasted distribution of property values. Furthermore the matrix and conduits compartments respond to different flow physics that can be approached by considering Darcy flow and pipe flow, respectively. Thus, one needs to employ a multi-physics model, an inversion method able to capture the properties contrast, and also to use data providing information on the localization of the conduits network and its connectivity.

We propose a large-scale 2-D application of characterization of the Lez aquifer in southern France, covering a surface of about 250 km². We take advantages of long-terms measurements within the framework of the MEDYCYSS observation site, part of the Karst observatory network (www.snokarst.org) initiated by the French institute INSU/CNRS. Drawdown signals measured in 11 wells and incorporating a periodic response due to a daily pumping at the aquifers spring were thus considered to identify the location of the conduit network. The periodic responses can provide connectivity information between wells in the inversion process, while non-periodic responses permit to better assess the large-scale property values of the whole aquifer. A Cellular Automata-based Deterministic Inversion (CADI) is used to generate a contrasted property field able to reproduce the measured signals in the 2-D distributed numerical model solving Darcy flows. However, pressure data alone remain limited to characterize the fast flows that can occur in the conduits network. Thus, the flow velocities in the preferential flow paths located with the pressure data are then reconstituted by inverting a set of different tracer tests responses at the Lez spring, considering this time a pipe flow physics in the model.
Quantification of Volcano Deformation caused by Volatile Accumulation and Release
Authors: Spang Arne , Burton Mike , Kaus Boris , Sigmundsson Freysteinn
Published: March 2022

Magma stored in the crust may exsolve a significant amount of volatiles, primarily CO2, but also H2O and SO2 if cooling promotes crystallisation and volatile exsolution. These volatiles may, over time, segregate and accumulate into a gas-rich foam at the roof of the magma body. This is the underpinning process to explain the frequently observed ‘excess gas’ produced in explosive eruptions, where the amount of erupted SO2 is much larger than can be explained by the mass of erupted products and the initial dissolved S content.

Here, we examine and quantify the buoyancy force exerted on the crust due to the presence of accumulated volatiles in the roof of a magma reservoir of exsolved volatiles. This foam has a significantly lower density than magma or the crust, and will therefore produce a buoyancy force which will manifest as deformation of the volcanic edifice above. A key concept in this work is that the accumulation of the foam layer may occur slowly over long time periods and therefore be challenging to detect. However, upon eruption, the gas phase will be suddenly lost, and the removal of the buoyant volatiles will result in syn-eruptive subsidence, in addition to that expected from the eruption of lavas.

We present three-dimensional, visco-elasto-plastic, thermomechanical modeling results which quantify the ground deformation arising from the growth and sudden release of a volatile reservoir. We find that the deformation is independent from the thermal structure of the crust and the shapes of the volatile and magma reservoirs. Instead, it is a function of the volume, density and depth of the volatile reservoir and crustal rigidity. This allows us to derive a scaling law for the volatiles’ contribution to syn-eruptive subsidence.

Applying our scaling law to the April 2015 eruption of the Chilean stratovolcano Calbuco, together with estimates of the pre-accumulated volatile mass, suggests that up to 25% of the observed syn-eruptive subsidence can be explained by the release of a buoyant reservoir of exsolved volatiles. Our results highlight the key role that volatile-driven buoyancy can have in volcano deformation and show a new link between syn-eruptive degassing and deflation. They also highlight that shallow gas accumulation and release may have a major impact on ground deformation of volcanoes and can serve as an explanation for inflation/deflation of up to a few cm.
Spatially distributed Added Value Index and Climate Change Downscaling Signal for convection permitting scale simulations
Authors: Ciarlo James , Coppola Erika , Pichelli Emanuela , Stocchi Paolo ,   FPS-Conv Team
Published: March 2022

A new metric that quantifies Added Value (AV) was developed that compares the difference within the entire probability distribution functions (PDFs) of the Regional Climate Model (RCM) and its driving General Circulation Model (GCM) with a high-resolution observation source, at every grid point, to obtain a spatial distribution of AV. This is important to assess the validity of the computationally expensive process of downscaling, especially for Convection Permitting Models (CPMs). The method can be adapted to focus on the tail-end of the distribution, since GCMs struggle to resolve precipitation extremes. To achieve this, the threshold value of the percentile of interest (for example, the 95th percentile) is obtained from the observation source and then applied to the PDF data as a filter, after which the corresponding AV can be obtained. This metric can also be adapted to assess the Climate Change Downscaling Signal (CCDS) of climate projections, by comparing to the corresponding historical data-set instead of an observation source.

This method is now being adapted to CPM simulations using a multi-model approach. The analysis is focused on both daily and hourly data from a 14-model ensemble of the ALP-3 domain using 5 high-resolution observation sources (GRIPHO for Italy; EURO4M for large alpine area; COMEPHORE for France; RADKLIM for Germany; and RdisaggH for Switzerland). The primary objective is to assess the added value of the CPM with the driving RCM, but a comparison to the GCM is also included. Preliminary results show that the CPM runs add value over the RCM, with possible emphasis in models/regions of lower RCM AV (requires confirmation by comparing RCMs to the driving GCMs). The analysis is will also focus on the CCDS metric of the near- and far-future simulations of the CPM, and the historical analysis is being replicated using hourly precipitation instead of daily.
Investigating the relationships among vegetation characters, saturated hydraulic conductivity and surface morphology at catchment scale by integrating new field data and morphometric analysis
Authors: Marzini Lorenzo , D'Addario Enrico , Papasidero Michele Pio , Amaddii Michele , Disperati Leonardo , Chianucci Francesco
Published: March 2022

Shallow landslides susceptibility assessment by physically based methods relies on the parametrization of both hydraulic and geotechnical properties of soils, which in turn depend on the conditions of root structures and vegetation cover. Vegetation roots contribute to the shear strength of soils, but their quantitative contribution is currently uncertain. Saturated hydraulic conductivity (Ks) is also relevant for slope stability as it influences infiltration rates and runoff. While the literature clearly shows the dependence of Ks on soil texture, there is a general understatement of the role of root structures on this parameter. Moreover, the distribution patterns of vegetation follow relations with surface morphologies which are not fully understood and therefore, are worthy of further investigations. For these reasons, this work focuses on the quantitative assessment of the influence of vegetation on shear strength for shallow landsliding and the investigation of the relationships between vegetation characters, saturated hydraulic conductivity and topographic parameters. Study areas affected by shallow landslides are chosen in the Garfagnana and Alpi Apuane regions (Northern Apennines, Italy), as well as in the Mt. Amiata volcano area (Southern Tuscany, Italy), where field measurements of below-ground vegetation (Root Area Ratio - RAR), above-ground vegetation (Leaf Area Index - LAI and vegetation load) and Ks are acquired inside, in the neighbour and far from shallow landslide sites. To this aim, a multi-temporal landslide inventory is already available for the study area. Below-ground data are collected in trench profiles, while above-ground data are acquired by using a digital relascope as well as implementing vegetation cover photography methods. Measurements of Ks are carried out by means of both constant and falling head approaches. The morphometric analysis is performed by using some morphometric variables (eg. slope and hillslope curvatures) derived from a digital elevation model with cell size of 10 m. Morphometric clustering of these variables allows us to extract a set of land units where the distribution of vegetation characters and Ks are assessed. First results show that: a) root reinforcement to soil in terms of root-related cohesion plays a relevant role within the soil depths involved in shallow landslides; b) the weight of above-ground vegetation plays a “mild” negative role on slope stability; c) Ks is correlated with both RAR and soil depth, suggesting possible criteria for the straightforward parametrization of input parameters.
Assessing and Forecasting Dengue Risk with Hydrological Data
Authors: Margutti Jacopo , van den Homberg Marc , Hierink Fleur , Ray Nicolas
Published: March 2022

We introduce a methodology to assess and forecast the risk of mosquito-borne diseases using open hydrological and socio-economic data, with a specific focus on scalability, i.e. applicability to countries where limited data is available. We apply this methodology to assess and forecast the risk of dengue in the Philippines. We embedded this model into a full Early-Warning Early-Action system, which includes a web portal to convey the information to disaster managers and a set of pre-defined preventive actions, to mitigate the impact of potential outbreaks. This system has been developed in collaboration with the Philippines Red Cross, which is now adopting it.
Trace metal availability in extreme microbial habitats of the Miocene Oberpullendorf Basin, Austria
Authors: Viehmann Sebastian , Kujawa Robert , Hohl Simon V. , Tepe Nathalie , Rodler Alexandra S. , Hofmann Thilo , Draganits Erich
Published: March 2022

Stromatolitic carbonates were formed in ancient microbial mats, and, thus, provide unique geochemical archives to reconstruct palaeo-environments in which microbial life thrived and evolved. In this study, we report the first geochemical data of Miocene stromatolites from the Oberpullendorf Basin (Austria) that were formed during the Badenian salinity crisis at the north-western coast of the Paratethys Sea. The combined approach of trace element data obtained by quadrupol ICP-MS with C-O isotopes of individual stromatolite laminae is used to reconstruct short-term variations of palaeo-environmental conditions in microbial habitats of the Oberpullendorf Basin.

Stromatolitic carbonates in the lower stromatolite units show negative δ13Ccarb values and typical shale-normalized seawater-like rare earths and yttrium (REYSN) patterns with positive LaSN, GdSN anomalies, super-chondritic Y/Ho ratios, and heavy REYSN enrichments to light REYSN, indicating an open marine-dominated depositional setting. Stratigraphic upwards, stromatolitic carbonates show suppressed seawater-like REYSN signatures and increasing δ13Ccarb values that argue for the development of a restricted environment. Seawater-like REYSN patterns and homogenously distributed negative δ13Ccarb values in the stratigraphic uppermost part resemble the transition to fully marine environmental conditions again. Enrichment factors of bio-essential elements (Fe, Mn, Co, Zn, Mo, W) reflect sufficient element availability during marine conditions but limitation during the development of the (semi)closed lagoon.

We show that combined REY, C isotopes, and enrichment factors of bio-essential elements bear the unique potential to reconstruct temporal changes in paleo-environments and determine the availability of bio-essential elements in microbial habitats. This approach provides the groundwork for a better understanding of the evolution and development of microbial metabolisms under severely different atmospheric-hydrospheric on planet Earth and beyond.
Multi-temporal sediment-yield estimates in a steep headwater catchment using UAV and sensor measurements. Challenges and results from the Rebaixader debris-flow monitoring site (Pyrenees).
Authors: Hürlimann Marcel , Ruiz-Carulla Roger , Moya José , Torra Ona , Buill Felipe , Núñez-Andrés M. Amparo
Published: March 2022

Debris flow and related processes strongly affect the morphology of headwater catchments and deliver large amounts of sediments into the drainage network. The Rebaixader monitoring site, which is situated in the Central Pyrenees, is a perfect location to analyse different slope mass-wasting processes and to quantify the sediment yield in this headwater catchment. Two types of data are available: first, yearly photogrammetric surveys by Uncrewed Aerial Vehicle (UAV) have been performed since 2016, and second, an instrumental monitoring system is operational since 2009. Therefore, six years of data can be compared by these two approaches. While the UAV surveys produce point-clouds, Digital Surface Models (DSM) and orthophotos, the monitoring system determines the total volume of each torrential flow by flow-depth sensors, geophones and video cameras. Therefore, the volumes of the torrential flows determined by the instrumental monitoring system were compared and contrasted with those obtained from the DoD (Dem of differences) of photogrammetric reconstructions from UAV flights.

The final values of the sediment yield are between 0.1 and 0.2 m3/m2/y, which shows that this torrential catchment has a very high erosion activity.

The experience from this study shows that the applied monitoring techniques make it possible to i) quantify the sediment yield, ii) identify the different phenomena, and iii) determine the spatial distribution of each process. Regarding the UAV-datasets, the appropriateness of using DoD or advantages of comparing directly the different 3D point clouds are other conclusions derived from this study that will be discussed.