bluuebunny/crossref_metadata_2025 huggingface dataset:
A global assessment of heatwaves since 1850 in different datasets
Authors: Hövel Laura , Hand Ralf , Brönnimann Stefan
Published: March 2022

Over the past century there was a significant increase in heatwaves in several regions around the globe. This increase is projected to continue with ongoing global warming and forms a serious risk for various ecosystems as well as human health. Changes in the occurrence and the characteristics of heatwaves since the middle of the 20th century are extensively studied in observational datasets and model simulations. However, there is a research gap concerning preindustrial (1850-1900) heatwaves and heatwaves in the early 20th century and their relation to forcings and large-scale variability modes.

In this study we analyse the occurrence of heatwaves and the spatial and temporal distribution of different heatwave characteristics since 1850 using different observational datasets (20CRv3 reanalysis, EUSTACE gridded temperature, HadEX3 and station data) and a 36-member ensemble of atmospheric model simulations. We compare preindustrial heatwaves to recent and projected heatwaves and analyse how global or local heatwave hotspots change over time.

We use a new approach, a 30-year running baseline climatology, which allows us to analyse heatwave characteristics across different centuries. Our analysis shows that the different observational datasets show a comparable distribution of heatwave characteristics. Furthermore, the atmospheric model based on observed volcanic forcings can also be used to analyse preindustrial and early 20th century heatwaves.  The agreement of the model simulations with the observational datasets allows to use the atmospheric model to analyse earlier preindustrial time periods that are not covered by observations. With our on-going analysis of preindustrial heatwaves, we consequently contribute to a better understanding of past climate extremes.

 
INTOMO -  Modeling of satellite to satellite excess phase (GNSS to LEO)
Authors: Cegła Adam , Hordyniec Paweł , Moeller Gregor , Trzcina Estera , Hanna Natalia , Rohm Witold
Published: March 2022

The number of tropospheric observations that are assimilated in current numerical weather forecasting systems, is large. From automatic weather stations, to geostationary satellites, from radiosondes to polar orbiting  microwave satellites. Amid the currently available data sources, GNSS stands out as a bias free, self calibrating, high fidelity temperature and water vapour measurements. 
Until recently GNSS was used weather forecasting only in two ways: as a ground-based point, high-frequency observation of integrated water vapour (IWV) or zenithal integrated observation of temperature and water vapour, or as a sparse space-based profile observation of temperature and water vapour content (provided as a refractivity or bending angle profile). In the last couple of years GNSS tomography, a 3D imaging technique, is gaining attention as a weather model data source. However, low space resolution combined with large uncertainty of the tomography reconstruction makes this technique difficult to apply in operational forecasting. 
Therefore this technique, to be considered as a valuable data source in weather models, has to be numerically stable with known repeatable uncertainty. We believe that a way forward is to combine space-based and ground-based observations using the tomography principle. A way forward is to effectively simulate the signal trajectory between the GNSS transmitter and GNSS receiver (Low Earth Orbiting LEO satellite). 3D ray-tracing modelling of the radio occultation (RO) event based on Numerical Weather Model is performed. The challenge here is to make these ray-tracing results comparable with excess phase observations at the LEO satellite.  
Modelling by 3D ray-tracing is performed by the modified Atmospheric TOMography (ATOM) software with the use of the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 model. This module uses the position of the GNSS satellites as starting point and iteratively propagates the signal path by collecting information on refractive parameters along its path based on nodal points. This study is based on the ten selected RO events from the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) report “Optimising tracking strategies for Radio Occultation. Task 1 - the profile dataset.”. Modelling was performed by varying the grid resolution of the ERA5 model and the length of a propagator step size segment to obtain total excess phase delay values. Additionally, Radio Occultation Processing Package (ROPP) 2D ray-tracing multiple phase screen simulation was run to confront obtained from ATOM phase delays. The COSMIC Data Analysis and Archive Center (CDAAC) observed excess phase was used as a reference data source. 
Fate of pyrogenic and organic matter in permafrost-affected soils: A two years in-situ incubation 
Authors: Schiedung Marcus , Bellè Severin-Luca , Abiven Samuel
Published: March 2022

Permafrost-affected mineral soils store large amounts of the soil organic matter (SOM) in high-latitude regions. These regions are large terrestrial carbon reservoirs and highly vulnerable to the global climate change. Global warming will cause rapid permafrost thaw and potentially accelerate decomposition of SOM. High-latitude regions, such as boreal and arctic ecozones, are regularly affected by wildfires with increasing intensity and frequency caused by global climate change. Wildfires produce pyrogenic organic matter (PyOM) during incomplete combustion of the fuel biomass. Little is known about the cycling of SOM and especially PyOM in permafrost-affected mineral soils, which limits our understanding of potential shifts in cycling and interaction with the soil mineral phase over time.

Here we study the fate of highly 13C-labelled (2-3 atm%) ryegrass organic matter and PyOM from the same feedstock (pyrolyzed at 400°C for 4h) during two years of in-situ incubation in boreal forest mineral soils. Soil cores (10 cm length and 6 cm diameter) were buried in the upper 10 cm of mineral soils under continuous and discontinuous to sporadic permafrost conditions at eleven forest locations (with six replicates) in Northern Canada. At the same locations, litter bags (green and rooibos teabags) were buried and soil temperatures were recorded. The soils cores were separated in three depth (0-3, 3-6 and 6-10 cm) to trace the vertical allocation of the applied organic matter. Density and particle fractionations are applied to identify mineral interactions of the ryegrass and pyrolyzed organic matter.

Preliminary δ13C results from the soil cores show a more extensive vertical allocation of ryegrass organic matter and PyOM in continuous permafrost-affected soils within the cores. This can be associated to the importance of freeze and thaw cycles for the carbon dynamics of permafrost-affected mineral soils. Tracing the labelled ryegrass organic matter and PyOM offers not only the opportunity to quantify the translocated fraction but also the decomposed proportion of the freshly added organic matter and thus understand short-term carbon dynamics. Preliminary results from the litter bags indicate a larger mass loss of slow cycling woody organic matter (rooibos tea) in discontinuous to sporadic permafrost-affected mineral soils, while larger mass losses of fast cycling organic matter (green tea) were observed in continuous permafrost-affected soils. These initial results indicate a complex cycling of organic matter in soils under different permafrost conditions.
The effect of vegetation adaptation on hydrological extremes in a changing environment and our (in)ability to predict it.
Authors: Hrachowitz Markus , Bouaziz Laurene , van der Ent Ruud , van Oorschot Fransje
Published: March 2022

Vegetation is a first order control on the partitioning between evaporative fluxes and drainage in the critical zone. The root-systems of vegetation access water that is stored in the subsurface. This, in general, ensures sufficient water supply for vegetation to satisfy its transpiration demand. Changes in root systems as consequence of vegetation adaptation to a changing climate or anthropogenic disturbances such as deforestation, lead to changes in the subsurface pore volumes that are accessible to vegetation.

These changes in vegetation water supply partly regulate changes in transpiration. As transpiration is globally the largest water flux from terrestrial hydrological systems, changes therein can cause substantial shifts in the partitioning of water fluxes, which, in turn, has direct impact on other parts of the hydrological response, such as groundwater recharge or river flow.

However, the majority of current-generation hydrological and land-surface models used to predict floods and droughts in a world under environmental change, relies on the assumption that vegetation, its root-systems and the associated accessible subsurface water supply do not evolve over time. The consequence is that the parameters representing this quantity in models are kept constant over time, while in reality the system is highly adaptive across multiple temporal and spatial scales. This assumption of stationary model parameters in a non-stationary environment has the potential to cause prediction biases.

In a step towards temporally adaptive models we here explore the utility of a water-balance-based method to estimate the catchment-scale subsurface volume accessible to vegetation and its historical evolution over time and to directly use it as parameter in hydrological and land-surface models. In a second step, trading time for space, we combine the above method with climate future projections and the Budyko hypothesis to estimate the future magnitudes of this parameter. This allows us to estimate the effect and relevance of changing vegetation properties on future hydrological extremes in a temporally adaptive model formulation.
Assessing the effect of mass withdrawal from a surface quarry on the Mw4.9 Le Teil (France) earthquake triggering
Authors: Maury Julie , Guillon Théophile , Aochi Hideo , Bazargan Behrooz , Burnol André
Published: March 2022

On November 11th 2019, the Le Teil, France earthquake occurred in the vicinity of a quarry. Immediately, the question was raised about the potential triggering of this earthquake by the quarry. However, another potential triggering source is a hydraulic effect related to heavy rainfall (Burnol et al, 2021). That’s why it is important to quantify precisely the mechanical effect of mass withdrawal. Results from different studies (Ampuero et al, technical report CNRS, 2019; De Novellis et al, Comm. Earth Env., 2021) agrees to a Coulomb stress variation of 0.15 to 0.2 MPa. However, these studies are based on Boussinesq solution supposing a homogeneous half-space that maximize the effect of the quarry. Here we used the distinct element method code 3DEC @Itasca in 3D to take advantage of an improved geological model and assess the impact of discontinuities as well as lithology. Our results show the maximum Coulomb stress change of 0.27 MPa at 1.4 km depth, a value of the same order as what is obtained with Boussinesq solution. A comparison between the location of the earthquake (Delouis et al, 2021) and the maximum Coulomb stress is realized. The maximum value is located at the intersection of the Rouviere fault with another local fault highlighting the interaction between these structures. However, the in situ stress field is not well-known, fault parameters are difficult to assess and there is some uncertainty on the volume of extracted material in the 19th century estimated by the quarry owner. Additionally, the presence of marl in the Hauterivian layer suggests it could have an elasto-plastic behavior. A parametric study has been realized to assess the effect on Coulomb stress change of these uncertainties taking plausible values for each parameter. We show that the uncertainty associated with our calculations affect the results within a range of less than 10%.
The difficult prediction of earthquake-induced landslide displacements: the case of Gaggio Montano (northern Apennines, Italy)
Authors: Di Paola Gianluigi , Lattanzi Giovanni , Rani Rodolfo , Castellaro Silvia , Berti Matteo
Published: March 2022

One of the most damaging side effects associated with seismic shaking within a certain distance from the seismogenic source are possible landslide movements. Seismic-induced landslide movements can cause serious problems to local communities even if the seismic shaking is of low intensity. To face these problems, local administrators are often forced to take unpopular planning decisions that affect the population. Therefore, detailed knowledge of landslide behavior to seismic shaking appears crucial.

In this study, we analyze the seismic response of a slow-moving landslide, which mainly affects clay soils. This landslide is located along a built-up area of about one thousand inhabitants (Gaggio Montano, northern Apennines, Italy), in a zone classified as medium seismic risk and its hazard potential has been assessed by considering geomorphological, geological, hydrological and seismic issues.

Firstly, we compiled a database of the existent geognostic investigations (cores, inclinometers, piezometers and CPT) and of the new geophysical surveys (HVSR and MASW) specifically acquired for this study. This allowed us to realize a detailed geological model of the slope and of the landslide body. Secondly, we run a 2D-numerical model of the seismic response of the slope. This allowed to evaluate the topographic and stratigraphic effects in response to hypothetical earthquakes with return period of 475 years. Finally, we applied the Newmark method to estimate the seismic-induced landslide movements.

A detailed sensitivity analysis was performed to account for the strong uncertainty in the data, especially regarding the geotechnical input parameters. The results show a dramatic influence of the shear strength parameters on the seismic-induced displacements. For example, by changing the effective friction angle by just 1°, the displacements vary more than 30 cm. This highlights the limitations of the conventional approach and the difficulty to predict the response of existing landslides to seismic shaking.
Gas phase induced carbonate precipitation - experimental proof and model verification
Authors: Zacherl Lilly , Baumann Thomas
Published: March 2022

Successful development of the geothermal energy sector requires an understanding of the geological systems and processes that occur within. In the North Alpine Foreland Basin, a hydrogeothermal play type, most sites are affected by inorganic precipitates which reduce the efficiency and safety of plants. Although the gas concentrations in the geothermal waters are generally low, any formation of an independent gas phase induces carbonate precipitation. A quantitative prediction of the precipitates, however, is not yet possible because kinetic data for gas phase induced precipitates is not available.

To address this issue laboratory experiments were run where a gas (CO2, air) was induced into a column containing an aqueous solution (tap water, water with high salinity). The scalings produced were analyzed by Raman spectroscopy, a mass balance of the process including the dissolving of scaling by inducing CO2 into the scaled column was based on ion chromatography data. The experiments show that by injecting air into tap water a full stripping of CO2 occurs which is the experimental proof of the disruption of the lime carbonic acid equilibrium by gas bubbles. The salinity of the initial solution influences - in agreement to previous investigations - the polymorph: only aragonite crystals were detected in tap water (ionic strength: 8.5e-03 mol/L), whereas only calcite crystals showed up in tap water with additional 0.2 g/L NaCl (ionic strength: 1.2e-02 mol/L).  Precipitation was inhibited when 120 g/L NaCl were added to the tap water before stripping (ionic strength: 2.1 mol/L).

The data were evaluated using a combination of hydrogeochemical calculation and precipitation kinetics (PhreeqC) with gas bubble kinetics (Python) and PEST++ for the final parameter adjustment. We successfully modelled the process of stripping, CO2-injection and the experiments with higher salinity with one model.  This experimental proof of the gas phase induced carbonate precipitation and the new adequate description of the scaling process is a further step to predictive maintenance for geothermal sites and a more reliable holistic site assessment during the planning stage. Together, this improves the sustainability and the attractiveness of the geothermal energy sector to investors.
Scalar transport induced by mesoscale eddies in the North Atlantic detected by a three-dimensional algorithm
Authors: Cavaliere Davide , Yang Chunxue
Published: March 2022

We present a study on mesoscale eddies to evaluate the transport of scalar properties in the North Atlantic (20°N-90°N) area, making use of a three-dimensional eddy detection and tracking algorithm. The algorithm uses sea surface height (SSH) fields for the identification of eddy sea surface signatures and the rotational velocity for vertical detection. With this system we can switch off the vertical filter quantifying the improvements coming from the additional vertical analysis, with respect to a standard SSH surface analysis. The horizontal eddy extension is detected from a depression/elevation area on SSH field. The eddy bottom is found at the depth where its mean rotational velocity vanishes. This feature behaves as an actual discriminator among eddies and spurious patterns, providing at the same time the vertical thickness. The analysis is performed on reanalysis and observational datasets at “eddy-permitting” and “eddy-resolving” spatial resolutions with daily and weekly frequencies. Through a preliminary investigation on eddie statistics, we are able to identify the relevant features of the eddies in the North Atlantic, finding strong seasonal and interannual patterns in the eddy population along almost all the datasets and in two-dimensional sea surface height satellite observations. We then provide an estimation of heat and salt transport through the depth integration of meridional transport where eddy masks are detected. A second, more detailed, estimation is carried out making use of the eddy tracking algorithm and considering the along-track transport of scalar properties. This allows us to identify the origin and the amount of heat and salt gained or released by eddies along their path, focusing, in particular, on the net transport between the North Atlantic and the Arctic Sea.
Land Use Changes and Agricultural Land Planning under Climate Change– A Case Study of Northern Yilan County, Taiwan
Authors: Lin Wen - Yen , Hung Chi-tung
Published: March 2022

According to the IPCC report, Taiwan is threatened by global warming and high frequency and influence of extreme weather, which will result in great impacts to its agriculture industry and the future of food security. Unfortunately, along with the rapid economic development and urbanization in Taiwan since the 1960’s, agricultural land use has become less competitive to industrial, commercial, and residential types of land uses under land use competition. To effectively enhance the resilience and conserve the agricultural lands which under the threats of climate change and the competitions of other types of land use, Taiwan’s Spatial Planning Act (promulgated on 2016/1/6) enlists Agricultural Development Zones, one of four major functional zones in National Spatial Plan, into demarcated functional zone and applying land use control. The zoning plan is expected to be completed by every city and county before the year of 2025, and one of the major issues is to consider the land use function changes of different locations. By comparing the 2007 and 2016 land utilization maps investigated by National Land Surveying and Mapping Center, this study identifies the 10-year changes of agricultural lands of northern Yilan county. To further investigate the spatial distribution of agricultural land changes, spatial analysis techniques such as multi-distance spatial cluster analysis (Ripley’s K Function) and Kernel density are employed to analyze the spatial clustering of changes. The spatial analysis results overlays with hazard risk maps, such as flooding, landslide, soil liquefaction, to support the decision making of future agricultural land planning.
Extrapolation of CRISM based spectral feature maps using CaSSIS four-band images with machine learning techniques
Authors: Fernandes Michael , Thomas Nicolas , Elser Benedikt , Rossi Angelo Pio , Pletl Alexander , Cremonese Gabriele
Published: March 2022

Spectroscopy provides important information on the surface composition of Mars. Spectral data can support studies such as the evaluation of potential (manned) landing sites as well as supporting determination of past surface processes. The CRISM instrument on NASA’s Mars Reconnaissance Orbiter is a high spectral resolution visible infrared mapping spectrometer currently in orbit around Mars. It records 2D spatially resolved spectra over a wavelength range of 362 nm to 3920 nm. At present data collected covers less than 2% of the planet. Lifetime issues with the cryo-coolers prevents limits further data acquisition in the infrared band. In order to extend areal coverage for spectroscopic analysis in regions of major importance to the history of liquid water on Mars (e.g. Valles Marineris, Noachis Terra), we investigate whether data from other instruments can be fused to extrapolate spectral features in CRISMto these non-spectral imaged areas. The present work will use data from the CaSSIS instrument which is a high spatial resolution colour and stereo imager onboard the European Space Agency’s ExoMars Trace Gas Orbiter (TGO). CaSSIS returns images at 4.5 m/px from the nominal 400 km altitude orbit in four colours. Its filters were selected to provide mineral diagnostics in the visible wavelength range (400 – 1100 nm). It has so far imaged around 2% of the planet with an estimated overlap of ≲0.01% of CRISM data. This study introduces a two-step pixel based reconstruction approach using CaSSIS four band images. In the first step advanced unsupervised techniques are applied on CRISM hyperspectral datacubes to reduce dimensionality and establish clusters of spectral features. Given that these clusters contain reasonable information about the surface composition, in a second step, it is feasible to map CaSSIS four band images to the spectral clusters by training a machine learning classifier (for the cluster labels) using only CaSSIS datasets. In this way the system can extrapolate spectral features to areas unmapped by CRISM. To assess the performance of this proposed methodology we analyzed actual and artificially generated CaSSIS images and benchmarked results against traditional correlation based methods. Qualitative and quantitative analyses indicate that by this novel procedure spectral features of in non-spectral imaged areas can be predicted to an extent that can be evaluated quantitatively, especially in highly feature-rich landscapes.
Coupled hydromechanical modeling of focused fluid flow structures
Authors: Polteau stephane , Wang Lawrence H. , Yarushina Viktoriya
Published: March 2022

Gas chimneys, fluid escape pipes, and diffused gas clouds are common geohazards above or below most petroleum reservoirs and in some CO2 storage sites. However, the processes driving the formation of such structures are poorly understood, as are the timescales associated with their growth or their role as long-term preferential fluid migration pathways in sedimentary basins. Here we present results from high-resolution simulations of geological processes leading to the formation of focused fluid flow structures. Our analyses indicate that time-dependent rock (de)compaction yields ascending solitary porosity waves forming high-porosity and high-permeability vertical chimneys that will reach the surface. The size and location of chimneys depend on the reservoir topology and compaction length. Our simulation results suggest that chimneys could have been formed and lost their connection to the reservoir on a time scale of a few months. We compare our modeling results with seismic data from the Ringhorne Oil Field, located in the central part of the North Sea over the Heimdal Terrace and the Utsira High [1].

[1] Yarushina, V.M., Wang, L.H., Connolly, D., Kocsis, G., Fæstø, I., Polteau, S., Lakhlifi, A., 2021. Focused fluid-flow structures potentially caused by solitary porosity waves. Geology.
Insights into biochar and metals tolerant bacteria in alleviating ZnO nanoparticles toxicity in plant
Authors: Bauer Tatiana , Rajput Vishnu D. , Minkina Tatiana , Natalya Chernikova , Beschetnikov Vladimir , Fedorenko Aleksei , Sushkova Svetlana , Mandzhieva Saglara
Published: March 2022

The application of nanoparticles (NPs) is increasing drastically, especially in crop production. The repeated inputs of metal-based NPs in agri-field could increase their concentration in soil, and cause a threat to sustainable crop production. Thus, the present study was designed to determine the role of spore-forming metal tolerant bacteria (MTB) and biochar (B) to alleviate the toxic effects of high dose of ZnO NPs (2000 mg kg-1) on plants (Hordeum sativum L.) spiked to the soil. For detailed evaluation, the five treatments were used such as 1) clean soil, 2) soil+NPs, 3) soil+NPs+MTB, 4) soil+NPs+B and 5) soil+NPs+B+MTB in plastic vessels in triplicate. The addition of MTB and B showed a promising impact on H. sativum growth in combination and individual inputs. The application of MTB to the contaminated soil reduced the mobility of Zn by 7%, mainly due to exchangeable compounds, and B reduced mobility up to 33%, because of a decrease in equally exchangeable, complex, and specifically sorbed forms. The combined introduction of MTB and B reduced most effectively the actual and potential content of Zn compounds in soil. The content of Zn in H. sativum tissues was increased drastically, especially in ZnO NPs contaminated soil. MTB and B in the contaminated soil reduced Zn accumulation in H. sativum roots by 20% and 63%, and in the aboveground tissues by 11% and 68%, respectively, compared to ZnO NPs polluted soil without amendments. The combined application of MTB and B showed the greatest decrease in Zn accumulation in H. sativum tissues. The root length and H. sativum height was decreased by 52% and 40% in contaminated soil. However, the addition of B, both separately and in combination with MTB reduced root length by 48% and 85%, and plant height by 53% and 40%, respectively, compared to polluted control. The anatomical results also showed an improvement in cellular- sub-cellular organelles, especially in chloroplast by B and in combination with MTB. The results indicate that metal-tolerant bacteria and biochar could be an effective soil amendment to decrease metal toxicity enhance crop growth, and improve soil health.

The research was financially supported by the Russian Foundation for Basic Research, project no. 19-34-60041.
An improved vertical correction method for the inter-comparison of Integrated Water Vapour measurements
Authors: Bock Olivier
Published: March 2022

Integrated Water Vapour (IWV) measurements from similar or different techniques are often inter-compared for calibration and validation purposes. Results are traditionally interpreted is terms of bias (difference of the means), standard deviation of the differences, and slope and offset parameters of a linear regression between the IWV measurements of the tested instrument with respect to the reference instrument. When the two instruments are located at different elevations, a correction must be applied to account for the contribution of atmosphere between the sites. Therefore, empirical formulations are often used. In this work it is shown that the widely-used model based on a standard, exponential, profile for water vapour density cannot properly correct the contribution of the atmospheric layer on the bias, slope, and offset parameters simultaneously. For example, correcting the bias degrades the slope and offset parameters, and vice-versa, with this model. An alternative method is proposed to derive an empirical model from real profiles observed by radiosondes. The method is developed for the special case of a tropical mountainous area with high IWV contents and strong diurnal and seasonal variations. Its application is illustrated with two examples, i) GPS to GPS comparisons and ii) GPS to satellite microwave radiometer comparisons.
Nowcasting the Orbit Decay of Earth orbiting Satellites
Authors: Drescher Lukas , Kroisz Sofia , Temmer Manuela , Krauss Sandro , Suesser-Rechberger Barbara , Behzadpour Saniya , Mayer-Guerr Torsten
Published: March 2022

The FFG funded project SWEETS (space weather effects on low Earth orbiting satellites) covers the analysis of a large sample of more than 300 ICMEs (interplanetary coronal mass ejections) from 2002 to 2017 and how they relate to the orbit decay of satellites. Based on the results by Krauss et al. (2018, 2020), we investigate the correlation between the interplanetary magnetic field of ICMEs and the variation of the neutral density in the thermosphere. So far, the satellite drops were calculated from either accelerometer measurements or kinematic orbits for the satellite GRACE at a height of approximately 490 km. Presently, we are working on constructing kinematic orbits for satellites in various heights so we will be able to cover altitudes between 300 to 800 km and a wider timeframe. The algorithm is also going to be improved with respect to multiple ICME events and the calculation of a so-called “effective Bz” component and its duration.

With the correlation and the real-time in-situ magnetic field data from satellites at L1 we were able to construct a nowcast. The nowcast algorithm is the basis of a new service called SODA (Satellite Orbit DecAy) which will be implemented in the ESA Space Safety Program (Ionospheric Weather Expert Service Center).
Global Sensitivity Analysis of an integrated parallel hydrologic model: ParFlow-CLM 
Authors: Qu Wei , Bogena Heye , Schüth Christoph , Vereecken Harry , Schulz Stephan
Published: March 2022

An integrated parallel hydrologic model (ParFlow-CLM) was constructed to predict water and energy transport between subsurface, land surface, and atmosphere for a synthetic study using basic physical properties of the Stettbach headwater catchment, Germany. Based on this model, a global sensitivity analysis was performed using the Latin-Hypercube (LH) sampling strategy followed by the One-factor-At-a-Time (OAT) method to identify the most influential and interactive parameters affecting the main hydrologic processes. In addition, the sensitivity analysis was also carried out for assumptions of different slopes and meteorological conditions to show the transferability of the results to regions with other topographies and climates. Our results show that the simulated energy fluxes, i.e. latent heat flux, sensible heat flux and soil heat flux, are more sensitive to the parameters of wilting point, leaf area index, and stem area index, especially for steep slope and subarctic climate conditions. The simulated water fluxes, i.e. evaporation, transpiration, infiltration, and runoff, are most sensitive to soil porosity, van-Genuchen parameter n, wilting point, and leaf area index. The subsurface water storage and groundwater storage were most sensitive to soil porosity, while the surface water storage is most sensitive to the Manning’s n parameter. For the different slope and climate conditions, the rank order of in input parameter sensitivity was consistent, but the magnitude of parameter sensitivity was very different. The strongest deviation in parameter sensitivity occurred for sensible heat flux under different slope conditions and for transpiration under different climate conditions. This study provides an efficient method of the identification of the most important input parameters of the model and how the variation in the output of a numerical model can be attributed to variations of its input factors. The results help to better understand process representation of the model and reduce the computational cost of running high numbers of simulations. 
Mechanisms behind climate oscillations in last glacial maximum simulations
Authors: Romé Yvan , Ivanovic Ruza , Gregoire Lauren
Published: March 2022

Millennial-scale variability has been extensively observed across the last glacial period records (115 to 12 thousand years ago) but reproducing it on general circulation models remains a challenge. In recent years, a growing number of climate models have reported simulations with oscillating behaviours comparable to typical abrupt climate changes, although often relying on unrealistic forcing fields and/or boundary conditions. This may become an issue when trying to review the mechanisms at stake because of glacial climates’ sensitivity to these parameters, notably ice sheets geometry and greenhouse gases concentration.

With the addition of snapshots of the early last deglaciation meltwater history over a last glacial maximum (~21 thousand years ago) equilibrium simulation, we obtained different regimes of climate variability, including oscillations that provides the perfect framework for studying abrupt climate changes dynamics in a glacial background. The oscillations consist of shifts between cold modes with a weak to almost collapsed Atlantic Meridional Ocean Circulation (AMOC) and warmer and stronger AMOC modes, with large reorganisation of the deep-water formation sites, surface ocean and atmospheric circulations. The phenomenon has a periodicity of roughly every 1500 years and can be linked to changes of about 10°C in Greenland. This new set of simulation suggests an intricate large-scale coupling between ice, ocean, and atmosphere in the North Atlantic when meltwater is discharged to the North Atlantic.

Most attempts at theorising millennial-scale variability have involved vast transfers of salt between the subtropical and subpolar gyres, often referred to as the salt oscillator mechanism, that in turn controlled the intensity of the north Atlantic current. We believe that the salt oscillator is in fact part of a larger harmonic motion spanning through all components of the climate system and that can enter into resonance under the specific boundary conditions and/or forcing. Illustrated by the mapping of the main salinity and heat fluxes on the oscillating simulations, we propose a new interpretation of the salt oscillator that includes the stochastic resonance phenomenon as well as the effect of meltwater forcing.
Global patterns of climate controlled root zone storage capacity based on a large sample of catchments
Authors: van der Ent Ruud , van Oorschot Fransje , Hrachowitz Markus , Alessandri Andrea
Published: March 2022

The root zone storage capacity (Sr) is the maximum volume of water in the subsurface that can potentially be accessed by vegetation for transpiration. It influences the seasonality of transpiration as well as fast and slow runoff processes. Sr is heterogeneous as controlled by local climate conditions, which affect vegetation strategies in sizing their root system able to support plant growth and to prevent water shortages. Climate controlled root zone storage capacities can be derived from the maximum water deficit in the root zone based on water balances in gauged catchments. However, root zone parameterization in most global hydrological models does not account for a climate control on root development, being based on look-up tables that prescribe worldwide the same root zone parameters for each vegetation class. These look-up tables are obtained from measurements of rooting structure that are scarce and hardly representative of the ecosystem scale. Several recent studies such as Van Oorschot (2021, https://doi.org/10.5194/esd-12-725-2021) have shown that replacing tabulated Sr values with climate controlled Sr estimates results in improvements in modelling catchment river discharge.

The objective of this research is to investigate global patterns of root zone storage capacity derived from catchment water deficits of a large sample of catchments worldwide. To this aim we explore relations of catchment Sr estimates and catchment climate descriptors such as climatological potential evaporation and precipitation, and catchment vegetation characteristics. These relations at a catchment scale will be used to develop a global coverage of climate controlled of Sr to replace tabulated root zone parameters in global hydrological and climate modelling.
The role of fluids in earthquake cycles: insights from seismo-hydro-mechanical models
Authors: Hegyi Betti , Dal Zilio Luca , Behr Whitney , Gerya Taras
Published: March 2022

Understanding the role of fluids in earthquake mechanisms and designing a computational framework which couples solid rock deformation and fluid flow is a major challenge in geosciences. We present results from a newly developed Hydro-Mechanical Earthquake Cycle (H-MEC) numerical code, which can resolve inertia- and fluid-driven seismic events, as well as long-term deformation in and off-fault. The two-dimensional (2-D) code uses a finite difference method with rate dependent strength, while an adaptive time-stepping allows the correct resolution of both long- and short-time scales, ranging from years during slow tectonic loading to milliseconds during the propagation of dynamic ruptures. We investigate the evolution of a simple strike-slip fault with fluid flow in a poro-visco-elasto-plastic compressible media. We analyze which parameters could have a first-order control on the seismic and aseismic slip behavior. In particular, we explore  the effects of fault permeability, shear modulus and the rate-strengthening yield strength. Our results suggest that the mentioned parameters influence the recurrence time of seismic cycles. Furthermore, permeability controls the long-term slip behavior and has a significant impact on the self-pressurization of pore-fluid pressure inside the fault zone, both during earthquake nucleation and propagation. Notably, for a range of different fault permeability a temporal transition from seismic events to aseismic slip can be observed, due to a gradual increase of pore-pressure over multiple earthquake cycles. This new numerical framework can help us better understand earthquake mechanisms and earthquake cycles, the role of fluids along fault-structures, and their effect on long term geodynamic processes. 
Overview of muography in geoscientific research
Authors: Nyitrai Gábor , Hamar Gergő , Surányi Gergely
Published: March 2022

Muography is a novel imaging method, using muon particles present in cosmic rays at Earth surface level. These naturally occurring high energy muons are able to penetrate even kilometers of rock. The count rate (flux) depends on the zenith angle of the incoming muon, as well as on the density-length of the rock (density integrated along the muon path up to the detector) thus providing a powerful tool to image the average densities of 10-1000 m rock layers. In some cases with multiple detector locations, even 3D density reconstruction is possible. The geometric constraint of muography is that the altitude of the particle tracking detector must be lower than the examined object level.

Applications arise in multiple disciplinaries, including volcanology, mining, archeology, civil engineering, speleology. In this presentation the technology of muography will be reviewed, the muon detectors developed in Wigner RCP Budapest will be introduced, and experiences learned from ongoing projects will be presented. 
Surveillance audio-based rainfall observation: a crowdsourcing approach
Authors: Wang Xing , Liu Xuejun , Glade Thomas , Wang Meizhen
Published: March 2022

Rainfall data with high spatiotemporal resolutions are of great value in many research fields, such as meteorology, hydrology, global warming, and urban disaster monitoring. Current rainfall observation systems include ground-based rain gauges, remote sensing-based radar and satellites. However, there is an increasing demand of the spatiotemporal rainfall data with high resolution. Thanks to the advocacy from many research institutions and international organizations, several innovative crowdsourcing ideas including opportunistic sensing and citizen science initiatives have been followed in recent years. Commercial cellular communication networks, windshield wipers or optical sensors in moving vehicles, smart phones, social medias, and surveillance cameras/videos have been identified as alternative rain gauges. In particular environmental audio recordings are a rich and underexploited source to identified and even characterize rainfall events.
Widespread surveillance cameras can continuously record rainfall information, which even provides a basis for the possibility of rainfall monitoring. Comparing the aforementioned methods, surveillance audio-based rainfall estimation has been discussed in existing studies with advantages of high-spatiotemporal-resolution, low cost and all-weather. Therefore, this study focuses on mining the rainfall information from urban surveillance audio for quantitative inversion on precipitation. Rain sound is generated by the collision of rain particles with other underlying objects in the process of falling. In real applications, the complex subsurface structure and random background noises from human activity in urban areas make surveillance rainfall sound vulnerable and surveillance audio-based rainfall estimation more challenging. In our study, the rainfall acoustic indicators were selected for rainfall sound representation. Deep learning-based rainfall observation systems were built based on urban surveillance audio data. Experimental results show the efficiency of our system in rainfall estimation. Our research is a new attempt to develop crowdsourcing-based rainfall observations, which can also provide a beneficent supplement to the current rainfall observation networks.
Climate Change in Mediterranean climate-type regions: A global approach based on the Köppen-Geiger classification
Authors: Urdiales Diego , Zittis George , Hadjinicolaou Panos
Published: March 2022

Mediterranean climate types (MC) are characterized by temperate, wet winters, and hot or warm dry summers and are mostly found at the western edges of all inhabited continents in locations determined by the geography of winter storm tracks and summer subtropical anticyclones. According to the Köppen-Geiger classification, this climate type is classified as Csa and Csb. Although such regions are limited in terms of area, their current population exceeds 700 million inhabitants globally. According to the scientific literature, most MC regions, became hotter and drier during the last century, while future climate projections suggest that these observed trends will continue for the upcoming decades. This combined effect of warming and drying will likely augment the climate change impacts in the MC societies and ecosystems. In this study we investigate how these regions will be impacted by global warming compared to the rest of the world and other regions in the same latitudinal zone. For defining the Csa and Csb regions of the Köppen-Geiger classification, we used the gridded CRU monthly precipitation and temperature observations. Then we analyzed temperature anomalies (area-weighted means) in different MC sub-regions, including North America (NA), South America (SA), Mediterranean Basin (MB), and the southwest of southern Africa (SAF) and southwest Australia (SAU). Our analysis shows that Csa and Csb regions worldwide have not undergone significant spatio-temporal changes during the last 120 years. Nevertheless, we found differences in the observed temperature trends, particularly in the last four decades (1981-2020). In more detail, the Mediterranean Basin with an observed trend of about 0.4 °C/decade has warmed faster than the global mean (0.28 °C/decade) and other MC regions (0.15-0.28 °C/decade). Finally, we will explore the future climate evolution of MC regions and if the observed trends will continue in the 21st century by analyzing a bias-adjusted and statistically downscaled dataset of CMIP6 climate projections. For supporting decision-making and climate mitigations efforts we focus on different global warming levels (e.g., 1.5, 2, and 4°C).

 

Keywords: Köppen-Geiger, Climate Change; Mean temperature anomalies; World’s Mediterranean climates

 

 

 
Large rock avalanches into a glacial lake(s): a new chapter of the Patagonian Ice Sheet story
Authors: Pánek Tomáš , Břežný Michal , Schönfeldt Elisabeth , Kapustová Veronika , Winocur Diego , Smedley Rachel
Published: March 2022

Although ice retreat is widely considered to be an important factor in landslide origin, many links between deglaciation and slope instabilities are yet to be discovered. Here we focus on the origin and chronology of an exceptionally large landslides situated along the eastern margin of the former Patagonian Ice Sheet (PIS). Accumulations of the largest rock avalanches in the former PIS territory are concentrated in the Lago Pueyrredón valley at the eastern foothills of the Patagonian Andes in Argentina. Long-runout landslides have formed along the rims of sedimentary and volcanic mesetas, but also on the slopes of moraines from the Last Glacial Maximum. At least two rock avalanches have volumes greater than 1 km3 and many other landslide accumulations have volumes in the order of tens to hundreds of million m3. Using cross-cutting relationships with glacial and lacustrine sediments and using OSL and 14C dating, we found that the largest volume of landslides occurred between ~17 and ~11 ka BP. This period coincides with a phase of rapid PIS retreat, the greatest intensity of glacial isostatic uplift, and a fast dropping of the glacial lakes along the foothills of the Patagonian Andes. The position of paleoshorelines in the landslide bodies and, in many places, the presence of folded and thrusted lacustrine sediments at the contact with rock avalanche deposits indicate that the landslides collapsed directly into the glacial lake. Although landslides along the former glacial lobe of Lago Pueyrredón continue today, they are at least an order of magnitude smaller than the rock and debris avalanches that occurred before the drainage of the glacial lake around 10-11 ka BP. Numerical modeling results indicate that large postglacial landslides may have been triggered by a combination of rapid sequential glacial lake drawdowns and seismicity due to glacial isostatic adjustment. We conclude that in addition to direct links such as glacial oversteepening, debuttressing and permafrost degradation, the retreat of ice sheets and the subsequent formation of transient large glacial lakes can fundamentally alter slope stability, especially if the slopes are built by weak sedimentary and volcanic rocks.