bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing greenhouse gas balances from three paludiculture crops after rewetting peat: Typha latifolia, Typha angustifolia and Azolla filiculoides
Authors: van den Berg Merit , Vroom Renske , Gremmen Thomas , van Huissteden Jacobus , Boonman Jim , van de Riet Bas
Published: February 2023

With the increasing demand to reduce greenhouse gas (GHG) emissions to meet the climate goals, rewetting of peatlands has gained attention as a promising measure. To reduce or stop peat oxidation, peat should be brought in anoxic conditions again by elevating the groundwater table. With this action, land becomes less suitable for traditional agriculture. Paludiculture would be a form in which wetland plants are grown and biomass is commercially used.In a field experiment, we studied the effect on GHG emissions from three different paludiculture species: Typha latifolia, Typha angustifolia and Azolla filiculoides. In this presentation we will focus on the following research questions: 1) Can CO2 emission reduction compensate increased CH4 emission when peatland is rewetted for paludiculture purposes? 2) What is contribution of ebullition and diffusive fluxes to the total CH4 flux of the different crop types? 3) What is the contribution of CO2 and CH4 to the total GHG balance with different crop types?From our results we show that all paludiculture crops reduce GHG emission compared to a drained peat meadow, with highest reduction for Azolla and lowest for Typha latifolia. CH4 emission in CO2-eq is as high or higher than the CO2 emission from drained peatland, but is compensated by net CO2 uptake. Typha roots in the sediment (resulting in plant mediated gas transport), which leads to lower contribution of ebullition to the total CH4 flux. Azolla had the highest ebullition rate, but has nevertheless the lowest total CH4 emission. Most probably because Azolla is a floating plant without roots in the soil. This means that less easily degradable carbon is brought into the soil by e.g. root exudates, and that there is also no CH4 transport through the plants.
Atmospheric turbulence and stability in and around long-range-transported Saharan dust layers as observed by airborne lidar and dropsondes
Authors: Gutleben Manuel , Groß Silke
Published: February 2023

Each year, during both boreal winter and summer, large amounts of Saharan mineral dust particles get carried westwards over the Atlantic Ocean towards the Caribbean. During their transport, Saharan dust particles can affect the Earth’s radiation budget in different ways. They can either directly scatter, absorb and emit radiation or have an indirect effect by modifying cloud properties through their interactions as cloud condensation nuclei or ice nucleating particles. While during the summer months – the peak season of transatlantic mineral dust transport – the particles are mostly advected in elevated Saharan Air Layers at altitudes of up to 6 km and at latitudes around 15°N, wintertime transport takes place at lower atmospheric levels (<3 km altitude) and lower latitudes. Our recent studies have shown that, during both boreal winter and summer, transported Saharan dust layers are characterized by enhanced concentrations of water vapor compared to the surrounding atmosphere. In this way the dust layers have to potential to modify the radiation budget not only through particle-radiation-interactions, but also through the absorption and emission of radiation by water vapor. This in turn may affect the atmospheric stability and stratification in and around the aerosol layers.In this study, the turbulent structure as well as the atmospheric stability in and around transported Saharan mineral dust is analyzed and possible differences between summer and wintertime are investigated. Therefore, measurements by both the water vapor and aerosol lidar WALES as well as by dropsondes are studied. They were collected upstream the Caribbean island of Barbados aboard the German research aircraft HALO (High Altitude and Long Range). To identify possible seasonal differences, not only data collected in boreal summer in the framework of the NARVAL-II campaign (August 2016), but also data collected in winter during the EUREC4A research campaign (January & February 2020) are analyzed. During both campaigns several research flights were designed to lead over long-range-transported Saharan mineral dust, thus allowing and in-depth investigation of their properties. The analysis shows that dust layers are highly turbulent and therefore help dust particles to stay airborne for a longer time. Additionally, the dust layers modify the atmospheric stability in a way that the evolution of marine clouds can be affected.In our presentation, we will give an overview of the performed measurements over long-range-transported Saharan dust layers and present the conducted analyses on atmospheric stability and turbulence from dropsonde measurements and calculated power spectra from lidar data.
The effect of earthquake rupture on the brittle-viscous flow of olivine
Authors: Mariani Elisabetta , Bagshaw Heath , Bilton Matt , Gardner Joe
Published: February 2023

Earthquakes are triggered by the sudden release of strain energy accumulated in the Earth’s crust and mantle. Around 55 earthquakes are located every day around the world, and 16 large earthquakes of magnitude greater than 7 are expected in any given year. These events are responsible for many deaths and for major natural disasters. The periodicity of rupture events is controlled by complex variables such as fault surface roughness, fault geometry, fluid-rock interactions, fluid pressure oscillations and the mechanics of the fault rock. Seismology, rock mechanics experiments and modelling have provided vital insights into the behaviour and frictional properties of faults, but the brittle-viscous response of rock to earthquake rupture and the passage of shock waves is currently not understood.Natural olivine exposed at the Earth surface, but derived from Earth’s upper mantle, display microstructures where brittle, frictional and viscous deformation coexist. Here we study the microstructures and textures locked in the geological record of the Premosello peridotite to understand the transient brittle-viscous deformation mechanisms triggered during large earthquakes, and their contribution to energy dissipation and build-up during the earthquake cycle.In this study we use electron backscatter diffraction (EBSD) in the SEM, as well as TEM analyses, to detail the micron to nanoscale structures of olivine in samples from the shallow upper mantle, collected near thick pseudotachylytes in proximity of the Mohorovičić discontinuity, which juxtaposes these peridotites with the lower crustal granulites of the Ivrea-Verbano Zone.
Amplification of sub-lithospheric dynamics by melt migration during plume-lithosphere interaction
Authors: Heyn Björn H. , Shephard Grace E. , Conrad Clinton P.
Published: February 2023

The interaction of mantle plumes with continental or cratonic lithosphere can result in (large-scale) volcanism and continental breakup, but these consequences seem to be limited to tectonic settings with pre-existing weak zones. In contrast, most parts of continental plume tracks, or their hypothesized tracks, show no extrusive magmatism. To reconcile this, our previous work has shown that even in the absence of melt, sustained plume-lithosphere interaction leads to lithospheric thinning, followed by elevated surface heat flux about 40-140 million years after the thermal anomaly in the mantle disappears. Therefore, melt-free continental plume tracks can be initially identified by a reduced lithosphere thickness, and later by an increased surface heat flux that temporally and spatially follows the thinned lithosphere.Yet, even if melt is not erupted, variable amounts of melt may still be generated at the base of the lithosphere above the plume, and this melt can impact local dynamics. In order to assess the role of melt in plume-lithosphere interactions, we have developed a recent suite of numerical models of mantle convection that include melting/freezing and melt migration. Our results indicate a much stronger time-dependence of models with melt compared to models without melt. In particular, small-scale convection at the base of the lithosphere becomes more vigorous, which leads to patterns that feature more localized and larger amplitude lithospheric removal and stronger asymmetry across the plume track. The generation of melt in a thinned area has a self-enhancing effect; more melt thins the lithosphere faster, resulting in more melt generation. However, the effect of thinning for a moving plate is limited, both with respect to the affected area and the time during which this local thinning can be sustained. As a result, the surface heat flux pattern, which is a long-pass filtered image of the lithosphere thinning, does not change significantly compared to a case without melt. However, melt migration brings heat closer to the surface, which increases the amplitude of the heat flux anomaly, and reduces the delay time following lithosphere thinning. The amplification of local dynamics by melt migration is especially pronounced if the plume interacts with pre-existing topography of the lithosphere-asthenosphere boundary (LAB), e.g. steps in lithospheric thickness. Depending on the LAB topography, multiple events of melt generations and magmatic intrusion can be generated by a single plume over tens of millions of years . Such a scenario may explain the pulse-like prolonged activity of the High Arctic Large Igneous Province (HALIP; which erupted between 130-85 Ma) and potentially an early phase of an Iceland plume track under Greenland (pre-62 Ma).
Introduction to the AQ-WATCH multi-model air quality forecast system
Authors: Li Cathy Wing Yi , Sofiev Mikhail , Timmermans Renske , Kranenburg Richard , Pfister Gabriele , Kumar Rajesh , Deroubaix Adrien , Huneeus Nicolas , Opazo Mariel , Caballero Tomas , Mo Dan , Zhang Xuelei , Leufen Lukas Hubert , Kleinert Felix , Schultz Martin , Granier Claire , Basart Sara , Salvi Olivier , Caillard Bastien , Brasseur Guy
Published: February 2023

AQ-WATCH (Air Quality: Worldwide Analysis and Forecasting of Atmospheric Composition for Health) is an international consortium, which co-develops and co-produces tailored products and services derived from space and in situ observational data for improving air quality forecasts and attribution. For this purpose, AQ-WATCH develops a supply chain leading to innovative downstream products and services for providing air quality information tailored to the identified needs of international users. This presentation will focus on one of the AQ-WATCH products, the AQ-WATCH air quality forecast system. Air quality forecast models provided by the AQ-WATCH consortium are set up for the focus regions in Asia and the Americas, based on the templates of Copernicus European and MarcoPolo-Panda Asian ensembles, but with much higher resolution and reliance on regional emission and observational information. The models are established over the focus regions using the meteorological and emission data taken from Copernicus repositories and other national archives and refined with local information wherever available. Each forecast model is then evaluated using local observational datasets and with the needs of the stakeholders. Machine learning workflows are being incorporated into the forecast system to improve both results from individual models and the model ensembles based on bias correction from observation data. Lessons learnt from model comparison in the focus regions will be presented. At last, the potential application of the system prototype, as well as the other AQ-WATCH products, namely the global and regional air quality atlas, the air quality attribution & mitigation, the dust and fire forecasts, and the fracking analysis tool, to other regions of the world will be discussed.
Exploring a new Central European site of paleoclimate reconstruction: First results from Erdmannshöhle (Southern Germany)
Authors: Mielke Aaron , Warken Sophie , Schröder-Ritzrau Andrea , Schorndorf Nils , Keppler Frank , Becker Arnfried , Piepjohn Karsten , Frank Norbert
Published: February 2023

Here we show preliminary cave monitoring and speleothem results from Erdmannshöhle in Hasel, one of the oldest show caves in Germany. The comprehensive monitoring programme of drip water and cave air started in late summer 2022 and is still ongoing. In addition, we present precise 230Th/U, petrography, and proxy data from several speleothems. Cave temperature and relative humidity loggers show constant values of 10.7 +- 0.5 °C and 100.0% humidity. First results of the cave air CO2 mapping show a strong seasonal ventilation pattern with summer values reaching >6000 ppmV. During winter time, CO2 drops to values < 1700 ppmV, favoring carbonate precipitation during the cold season. Drip water is collected bi-monthly from 10 drip sites located in three chambers of the second horizontal cave level where speleothem growth is still active. First data of drip water stable isotope values agree with the local meteoric water line. In addition, abundances of dissolved minor and trace elements such as Mg, Ba, Sr, K, and Na, as well as anions (e.g., Cl, NO3, PO4, SO4) are analyzed. The data will be compared to the recently precipitated carbonate collected on watch glasses which are mounted on top of drip rate loggers.230Th/U dating of speleothems from Erdmannshöhle is promising due to relatively high U contents in the range of 0.05 - 1 µg/g, and low detrital Th contamination. Analysis of drill cores from 25 stalagmites and flowstones from different cave chambers and cave levels extend the preliminary survey of Becker et al. (2020). The data shows that speleothem growth was active in Erdmannshöhle at least for the last 162 ka (Becker et al. 2020), in particular during past warm interglacial periods and the Holocene. Preliminary exploration of proxy data from two speleothems covering several parts of the Holocene demonstrate the high potential of Central European paleoclimate reconstruction. Stable oxygen records suggest a strong link to North Atlantic climate variability. In addition, carbon isotope and high resolution laser ablation ICPMS trace element records are explored for their paleoclimatic significance.In summary, Erdmannshöhle has excellent preconditions for the continuous reconstruction of past Central European climate, and this comprehensive monitoring effort will provide an important step towards interpreting speleothem proxy data. ReferenceBecker, A., Piepjohn, K., & Schröder-Ritzrau, A. (2020). The Erdmannshöhle near Hasel, SW Germany: karst environment and cave evolution. Swiss Journal of Geosciences, 113(1), 1-25.
Fingering Flow in the Subterranean Estuary under Tidal Influence
Authors: Delwar Rezwana Binte , Grünenbaum Nele , Greskowiak Janek , Massmann Gudrun
Published: February 2023

In a coastal aquifer under tidal influence, seawater recirculates beneath the intertidal zone along the classical saltwater wedge (SW). The recirculating seawater on top of the saltwater wedge is called upper saline plume (USP). In between the USP and SW, a freshwater discharge tube (FDT) prevails. Both fresh and saline water components leave the aquifer and flow into the sea as submarine groundwater discharge (SGD). Due the density-gradient across the saline/fresh interface, the USP is prone to instability, resulting in the fingering flow. Whether the USP becomes instable or not depends on several factors, for instance, hydrological (tidal amplitudes, storm surges, precipitation, freshwater flux), morphological (beach slope, aquifer depth), and physical-chemical (temperature, pressure, and dissolved solids of the fluid) boundary conditions as well as aquifer physical properties (porosity, permeability). Unstable USP, which tends to sink to the bottom of the aquifer generating salt fingers, has been described in the context of numerical studies and physical experiments. Yet, flow and transport patterns and the effects of the boundary conditions and parameters described above are not well understood. USP alters the travel path and time of terrestrial nutrients, metals, and contaminants from the coastal aquifers to the marine environment, necessitating a thorough investigation to reveal its critical role in the hydrological cycle. For the present study, laboratory sand tank experiments have been carried out to evaluate the effect of homogeneous/heterogeneous conditions, beach slope, fresh groundwater influx and tidal amplitude on USP instability. The results have been used to delineate the conditions that either promote or suppress fingering flow in a tide affected aquifer.  The results define beach slope as the foremost parameter, along with tidal frequencies and beach morphology for the instability of USP. The tank experiments also support the general idea that the presence of low permeable layers disrupts USP formation. Regardless of the aquifer medium, the 3D effect of the salt fingers was observed during the experiments. Furthermore, the laboratory results are found to be consistent with results from previously undertaken generic simulations for field scale conditions. It appears that both laboratory and field scale behavior can be predicted in previously developed non-dimensional stability diagram that separates unstable from stable conditions.  
Reducing uncertainty in extreme weather vegetation stress modeling using satellite-model approach at high resolution
Authors: Verma Arpita , Francois Louis , Jacquemin Ingrid , Lanssens Benjamin , Hambuckers Alain , Ugolotti Alessandro , Tölle Merja , Hallot Eric
Published: February 2023

Vegetation is a key driver for carbon uptake from the atmosphere to the land. Yet episodes of plant stress and mortality associated with drought and heat waves due to persistent lack of precipitation have been reported over the last decades and are expected to increase under ongoing climate change. It is presumed that climate-related vegetation stress results in progressively worsening plant health and rising mortality. However, the mechanisms driving such mortality are still up for debate because of the complex interconnections between the processes and the factors. Monitoring plant stress and mortality at the ecosystem level remains challenging to quantify since long-term, tree-individual, reliable observations are uncertain. For this reason, here we adapted a satellite-model approach to work on regional forests, before up scaling the results to the global forest.In Belgium, the Wallonia region is covered by 30% forests which are the highest among all the three regions. While with the consecutive recent extreme events especially the droughts and heat waves of 2018, 2019, 2020, and 2022 caused water stress and bark beetle attack. According to the 35 years (1985-2022), land use land cover change extracted by LANDSAT 5,7, and 8 satellites, there is no significant change in forest land in Wallonia, Belgium. Meanwhile, in the current years 2021-2022, there is a decrease in the tree canopy with intensive forest management due to tree plant stress. On the other hand, in Wallonia, the forest is distributed in a significant patch of broadleaves, coniferous leaves, and mixed forest. However, we found that consecutive drought events cause water stress on specific plant species like Norway spruce which are in vulnerable states. For example: in a mixed forest when bark beetle or Scolytinae attacked the spruce tree it is more attracted to the other trees and in this consequence tree species –like  birch and oak –are now also in premature death or deteriorating tree health. In this study, we are using a high spatial resolution (25cm) remote sensing images using Artificial Intelligence and machine learning techniques to find out pixel-based individual plant stress or mortality. In addition, the high-resolution tree mortality extracted data will be used to calibrate CARAIB dynamic vegetation model and analyze the impact of extreme events on trees during the recent past and the future (until 2070). In conclusion, from this study, we plan to improve our model regarding the implementation of plant traits and species mortality aspects towards a better prediction of forest tree species' vulnerability to future extreme weather events.
A multiscale MPMxDEM model for simulating snowpack deformation and failure.
Authors: ozenda olivier , Chambon Guillaume , Richefeu Vincent
Published: February 2023

Fracture propagation in the snow-pack can lead to slab avalanches triggering. In the brittle deformation regime, snow can be viewed as a loose cohesive material. As shown in Discrete Element (DEM) simulations, the mechanical response of centimetric snow samples present complex patterns including strong strain-softening and volumetric collapse, with an important sensitiveness to the microstructure. On the other hand, avalanches involve large deformations and can propagate over hundreds or thousands of meters.To tackle the challenge of modelling this wide variety of spatial scales, a double-scale MPMxDEM approach is proposed.The MPM (Material Point Method) solver is used to compute the evolution of the flow at large scale and embeds a homogenized numerical constitutive law. Hence, each macroscopic lumping point is associated to its own microstructure, e.g. its own DEM cell, evolving independently. At the micro-scale, a loose assembly of spheres is considered with a cohesive contact law.The ability of this method to capture the main features of snow mechalical behavior in a more robust manner than empirical analytical constitutive models will be investigated by simulating elemenary laboratory tests like oedometric test and field experiments like the Propagation Saw Test (PST).
Characterizing the drivers of organic matter fluctuations in surface water lakes: the case of the Gileppe water reservoir in Wallonia (Belgium)
Authors: Verstraeten Elise , Alonso Alice , Vanclooster Marnik
Published: February 2023

Many surface water lakes in northern Europe have seen a rise in their organic matter content. When the water is used for human consumption, this has an indirect effect on human health, by increasing the risk of pathogens appearance and of biofilm formation after water treatment. Besides, organic matter negatively affects the color, odor and taste of water, which displeases the consumers. In order to ensure a good drinking water quality at the tap, its treatment should thus be adapted to the organic matter content.In this study we (i) characterize the trend and seasonality patterns of organic matter in the Gileppe Lake over the last 20 years and (ii) unravel mechanisms causing the observed fluctuations using time series statistical modelling. The water reservoir created by the Gilleppe dam in the North of Wallonia has an available volume of 3.100.000 m³. It is used to supply a hydro-electric power plant, and to provide drinking water to the city of Verviers and its surroundings. The water producer « Société Wallonne des Eaux (SWDE) » extracts an annual volume of around 14 million m³ to that end. The SWDE has been measuring the quality of the extracted water since 1991, at an increasing frequency. These measurements include parameters related to organic matter content such as total organic carbon (TOC), color and chemical oxygen demand.The TOC concentrations in the Gileppe lake indicate there has been a rise in organic matter in the Gileppe lake since the 90’s, as the concentration was 3,7 mg/l in October 1997, and increased to 10,4 m/l in October 2019. The TOC also has a seasonal variability, with the highest concentration peaks being reached during the autumn.We characterize the evolution of the potential drivers of the increasing trend and the seasonality: climate (precipitation, T°), land use (mainly forest cover area and type) and anthropogenic pressure (presence of septic tanks, wastewater release, agricultural runoff). We then investigate if, according to the literature, the evolution of these variables could explain of the observed organic matter trends and seasonality.
Designing and running a student led Climate Change and Sustainability module
Authors: Petrie Elizabeth , Nanthakumar Vidya , Marot Sam , Toney Jaime , Lemal Nimaya , Antener Sydney , Murphy Ben
Published: February 2023

We describe the creation and running of ‘Introduction to Climate Change and Sustainability’ a student led interdisciplinary undergraduate module. The course was designed and led by 2 undergraduate students with a passion for climate action, bringing together an interdisciplinary array of academic speakers from different departments. The format has been a mixture of lecture and in-class discussion, with assessment using presentations and group work. It has now been run 3 times. We will discuss some of the experiences and challenges around designing and running a credit bearing module with a joint team of students and staff support, with thoughts from running the course both online and in-person. 
Sustainable agricultural strategies to address limited freshwater availability and meet food demand in the Nile River Basin
Authors: Sardo Martina , Rulli Maria Cristina , Chiarelli Davide Danilo
Published: February 2023

Providing healthy food from a sustainable food system, while satisfying the demand of a growing population, is one of the major challenges of the century.  The limited agricultural land and water represent the main boundaries to meet the food demand of a growing population (Davis et al., 2014, 2017). Moreover, availability of natural freshwater is expected to furtherly decline in future due to climate change (Rodell et al., 2018) – especially in arid regions – and, thus, there is an urgent need to reshape the agricultural system to sustainably feed a global population approaching 9 billion people in the next century (Godfray et al., 2010).Food security in the Nile Basin is strictly related to the availability of freshwater resources, which are increasingly threatened by climate change and future demographic trends. Currently, food production is insufficient to meet the population food demand, and all Nile countries are currently net food importers. Healthy food is also needed to address malnutrition within the poorest rural communities in the Nile countries. Countries in the Basin are highly affected by undernourishment - linked low dietary energy - iron-deficiency-induced anemia and diabetes. The agricultural sector is the largest consumer of the Nile waters and, thus, the state of the food system has profound implications for attaining water security in the Nile Basin (NBI, 2020).In this study we suggest a sustainable agricultural strategy to enhance sustainable a food system within the Nile River Basin. We couple the WATNEEDS hydro-agrological (Chiarelli et al., 2020) model with a linear optimization algorithm to reshape the current cropland with the aim of producing more healthy food, with several benefits for the ecosystem (e.g., reduced irrigation water consumption) and human health. Cropland redistribution can be coupled with agricultural intensification and diet shift generating, at the meso-scale, benefits in terms of irrigation water savings and increase in food self-sufficiency. We first evaluated the amount of irrigation water and the crop production related to the current crop distribution and second, we identified potential differences in food production and water consumption between the current and optimized crop distributions. We use the WATNEEDS model to quantify spatially distributed crop water requirements, - namely blue and green water requirements - which are the volumes of water needed to compensate crop water losses through evapotranspiration. Our results show that crop redistribution increases food availability and, thus, the percentage of population sustained sustainably with the local agricultural production, reducing the pressure on the currently available renewable freshwater resources of the Nile.
Laser-melting Bismuth - A case study for X-ray imaging at high pressure and temperature
Authors: Massani Bernhard , Husband Rachel , Campbell Daniel , Sneed Daniel , Jenei Zsolt , Liermann Hanns-Peter , McWilliams Stewart , O'Bannon Earl
Published: February 2023

Our understanding on how opaque materials respond to extreme compression and high temperatures heavily relies on x-ray techniques. While X-ray diffraction is a powerful approach, some properties such as viscosity are experimentally not accessible with such approaches.  Application of x-ray imaging has been widely applied in extreme pressure and temperature conditions using multi-anvil presses, but obtaining sufficient space and time resolution for similar experiments using diamond anvil cells, at commensurately higher pressure and temperature conditions, have been challenging. We present recent developments in synchrotron X-ray imaging at the ECB beamline at PETRA III, DESY used in combination with laser heated DAC. Simultaneous X-ray imaging and diffraction allows for deeper insight in properties of materials under high pressure as well as the direct correspondence of phase transition diagnostics.  We present a case study of bismuth in the laser-heated diamond anvil cell showing detection of solid-solid and solid-liquid transitions and explore how X-ray imaging can be used to determine viscosity of molten bismuth under pressure.
Decadal variability of eddy temperature fluxes in the Labrador Sea
Authors: Danek Christopher , Scholz Patrick , Lohmann Gerrit
Published: February 2023

Small-scale eddies play an important role in preconditioning and restratifying the water column before and after mixing events, thereby affecting deep water formation variability. Results from a realistic eddy-resolving (~5 km local horizontal resolution) ocean model suggest that small-scale temperature fluxes due to turbulent potential to kinetic energy conversion are the main driver of mixed layer restratification during deep convection in the Labrador Sea interior and the West Greenland Current. This resupply of heat due to turbulent upward buoyancy fluxes exhibits a large interannual variability imposed by the atmospheric forcing. Eddy fluxes only become active in periods of strong buoyancy loss, while being quiescent otherwise. In a low-resolution (~20 km) control simulation the modeled turbulence is strongly reduced and the associated modeled and parameterized heat fluxes are too weak to increase stratification.
Recurrence analysis of large-scale dynamical properties of terrestrial mammal evolution
Authors: Stankevič Robertas , Bekeraitė Simona , Spiridonov Andrej , Juchnevičiūtė Ivona
Published: February 2023

Contrary to ecology, biology and climate science, analysis of nonlinear dynamics in paleontological time series is still relatively uncommon. Palaeontology tend to focus on events such as mass extinctions or radiations over dynamical processes and relationships. However, all parts of the Earth system, including the biota, are interrelated at multiple scales, showing feedback relations and nonlinearity. Nonlinear analysis of global palaeodiversity dynamics and its coupling with abiotic variables could offer a fresh view into a long-running question of the relative importance of biotic and abiotic factors in macroevolution by identifying interactions and responses not amenable to classical methods of time series analysis. As a part of our inquiry into causal explanation of the drivers of mammal evolution, we present our analysis of the dynamics of Cenozoic land mammal evolution, based on high resolution time series data and methods of recurrence plots and causal inference. Using PyRate, a Bayesian palaeodiversity analysis framework, we estimate diversification parameters and individual taxon lifetimes of several extinct Paleogene mammal orders and several extant large bodied orders Carnivora, Proboscidea, Artiodactyla and Perissodactyla. We then use recurrence analysis tools developed by the author to investigate dynamics of the evolution of the aforementioned taxons, identifying regime transitions and regions of deterministic and chaotic regimes over multi-million year timescales. Abrupt changes in species composition are indentified particularly in Perissodactyla recurrence plots. First and the most abrupt change occured at ca. 32 Ma, corresponding to Eocene-Oligocene extinction event. Another prominent change indentified at ca. 17 Ma, corresponding to Middle Miocene disruption. Both concide with changes in δ13C and δ18O isotopic record (Westerhold et al. 2020). In search of signatures of general synchronisation, we performed joint-recurrence plot analysis between matrices of diversity composition, δ13C isotopic record and δ18O-derived global temperature time series. Our preliminary results shed light on diversification dynamics of the main terrestrial mammal orders and similarity over time and coupling with the climatic and carbon cycle dynamics of the Earth. We compare them with findings of causal analysis of climate and diversification time series, using the same datasets and transfer-entropy based causal inference tools. The relative degrees of herbivore and carnivore diversity couplings with climate is also discussed.
Semi-probabilistic flood risk analysis including climate change uncertainties
Authors: Pereira Fernando , Nossent Jiri , Leyssen Gert , Van Uytven Els , Blanckaert Joris , Adams Roeland , Franken Tim
Published: February 2023

Flood risk analysis is of the utmost importance for policy makers and water managers as an input for the design and management of water bodies. In order to assess the frequency and severity of potential extreme floods, both data analysis and modelling, or even a combined approach can be employed. However, the spatial and temporal context of flood events is often complex, in particular when the extreme water levels can be caused by a combination of extreme upstream discharges, extreme downstream water levels and/or extreme wind events, and given the additional impact of climate change. This complexity hampers a straightforward analysis and extrapolation of rare flood events. We therefore present a semi-probabilistic flood risk analysis, that combines an ensemble approach, using different hydrological models and various climate scenarios, with a methodology that describes the extreme domain of the different flood drivers by a nested Copula. The latter Copula is based on the individual univariate extreme value distributions of each of the drivers. Synthetic design conditions for different return periods can be generated by a stratification of the obtained probability domain for extreme events. An application for the catchment of the River Scheldt in Belgium will be used to illustrate the presented approach for flood risk analysis, including an ensemble of 3 hydrological models, multiple climate scenarios for different time horizons and different projections of sea level rise.
Marine litter tracking system: a case study with open-source technology and a citizen science-based approach
Authors: Guarnieri Antonio , Merlino Silvia , Locritani Marina , Delrosso Damiano , Biancucci Marco , Paterni Marco
Published: February 2023

It is well established that rivers are amongst the most important carriers of the plastic pollution found in the oceans. However, the main processes contributing to plastic and debris fate through riparian systems is still poorly known and understood. The Marine Litter Drifter project from the Arno River aims at using modern consumer software and hardware technologies to track the trajectories and evolution at sea of real Anthropogenic Marine Debris (AMD) from rivers, with a specific focus on the Arno River, in Italy. Innovative and low cost “Marine Litter Trackers” (MLT) were designed, assembled and used in this framework as they are reliable, robust, self-powered and they present almost no maintenance costs. Furthermore, they can be built not only by those trained in the field but also by those with no specific expertise, including high school students, simply by following the instructions.Several dispersion experiments were successfully conducted using different types of trackers in different seasons and weather conditions. The maximum distance tracked was 2845 km for a period of 94 days. The activity at sea was integrated by lagrangian numerical models supporting the planning of the deployments and the recovery of the drifters. The models, in turn could benefit from the observed tracking data for calibration and validation and serve as tools to study and interpret the processes driving macro plastic displacement at sea. In this presentation we describe this activity and we discuss the dynamics of marine litter (ML) dispersion in the Tyrrhenian Sea on the basis of these integrated monitoring tools, as well as the potential of open-source approaches including the “citizen-science” perspective for both improving Big Data collection and educating/awareness-raising on AMD issues.
National Hydrological Modelling of Climate Adaptation Impacts for the UK
Authors: Smith Ben , Lewis Elizabeth , Birkinshaw Stephen
Published: February 2023

Climate Change is likely to have a significant effect on river flows and associated floods and droughts in the coming decades. As such, it is key to understand the nature and severity of these changes and the potential costs and benefits of potential impact mitigation strategies at both a catchment and national scale. We have developed and demonstrated a methodology for national scale modelling of river flows under twelve climate forcing scenarios and have evaluated the impacts of potential adaptation strategies with regards to river flow.This work forms part of the OpenCLIM project, which aims to create a scalable framework that enables users to integrate models and datasets from across a range of sectors (such as urban development, hydrology, and heat risk). This integrated, cross-sectoral approach is necessary to capture the complexities of climate response and will enable users to explore the potential impacts of climate change and adaptation strategies.A spatially distributed, physically based hydrological model (SHETRAN-UK) has been setup for 701 catchments across Great Britain and Northern Ireland. Both uncalibrated and auto-calibrated simulations were run for historical periods and future climate scenarios (using UKCP18 regional climate projections). Strong model performance across the country allowed for analysis of the effect of climate change and storylined urban development on future river flows and the impact of potential adaptation strategies, specifically relating to floods and droughts.Results from an urban development model were used to represent potential change in urban areas while natural flood management strategies were implemented by increasing woodland cover and storage in the model. Flows from the models were then fed into models for estimating economic flood damages.This talk will discuss the methods and findings from the project, comparing them to other studies and will discuss the relevance of continued investigations into modelling climate/adaptation impacts as well as the lessons learnt regarding autocalibration and the high-performance computing approach (DAFNI & JASMINE).
Scenario-based groundwater modeling of a raised bog with Mike She
Authors: Friedrich Sebastian , Gerner Alexander , Gabriele Chiogna , Disse Markus
Published: February 2023

Water table modeling in peatlands is often done on the large scale and, consequently, based on coarsely resolved models. The models commonly used in literature are often either not capable of modelling the full water cycle or they are not purely physically based. In particular in Bavaria there is a high number of small isolated peatlands with a dense drainage network, therefore a coarse model is not feasible. For rewetting success and climate impact analysis the fully integrated and largely physically based Mike She modelling software by DHI was used in the KliMoBay Project.
The main goal was to achieve a temporally and spatially highly resolved model enabling water table investigations for different rewetting stages as well as associated vegetation and soil changes.
For this purpose, the partially rewetted raised bog Königsdorfer Weidfilz in Bavaria was monitored and replicated in Mike She. Active and partially rewetted drainage ditches were implemented in the hydrodynamic model Mike Hydro and coupled with the Mike She model. After calibration and validation on twelve automatic water level gauges, scenario analyses were conducted. Compared with the climatic reference period (1961 – 1990), the dry year 2018 and the average year 2020 were modeled for three different scenarios: 1. current state, 2. drainage ditches deactivated, 3. vegetation and soil property succession after rewetting. The influence on the water table was analyzed based on a reference depth of - 0.15 m which is considered as an average threshold for climate impact. For this purpose, seasonal and annual mean water table maps were created, as well as standard deviation maps to portray high water table dynamics within the respective mean season.   
As the model results show, it is possible to investigate even small peatland areas for their rewetting potential. Furthermore, we could show the positive impact of rewetting measurements on reducing climate active areas with water levels below - 0.15 m in raised bogs. Vegetation and thus soil property changes in the model – which are assumed to occur after sufficient rewetting along with active acrotelm growth – increase the effect even more. Although, the impact of dry seasons is still significant, the resilience of the peatland increases.
Using the example of the partially rewetted raised bog we were able to proof, that areas with different drainage states could be modeled. The areas rewetted in the respective model scenario react similar to the areas already rewetted in nature. Thus, we assume that the method is capable for planning stages. Consequently, it can offer a descriptive decision support tool. However, the process of model setup, calibration and validation is rather time consuming. Regarding fen peatland management, further models can be set up considering the capability of Mike Hydro to model controllable weirs.
Observations of Off-Equatorial ULF Waves and Simulations of their effects on Radial Diffusion in the Radiation Belts
Authors: Sarris Theodore , Li Xinlin , Zhao Hong , Papadakis Kostis , Liu Wenlong , Tu Weichao , Angelopoulos Vassilis , Glassmeier Karl-Heinz , Miyoshi Yoshizumi , Matsuoka Ayako , Shinohara Iku , Imajo Shun
Published: February 2023

Magnetospheric ultra-low frequency (ULF) waves are known to cause radial diffusion and transport of hundreds-keV to few-MeV electrons in the radiation belts, as the range of drift frequencies of such electrons overlaps with the frequencies of the waves, leading to resonant interactions. Numerous expressions have been derived to quantitatively describe radial diffusion, so that they can be incorporated in global models of radiation belt electrons; however, most expressions of the radial diffusion rates are derived only for equatorially mirroring electrons, and are based on estimates of the power of ULF waves that are obtained either from spacecraft close to the equatorial plane or from the ground. Recent studies using the Van Allen Probes and Arase have shown that the wave power in magnetic fluctuations is significantly enhanced away from the magnetic equator, consistent with models simulating the natural modes of oscillation of magnetospheric field lines. This has significant implications for the estimation of radial diffusion rates, as higher pitch angle electrons will experience considerably higher ULF wave fluctuations than equatorial electrons. In this talk, we present recent results on the distribution of the magnetic field wave power as a function of magnetic latitude in different local time sectors and under different solar and geomagnetic conditions. Furthermore, using analytic functions of wave amplitudes in 3D test particle simulations, we simulate the change in L over time for particles of different pitch angles; this change in L can be translated to novel analytic diffusion coefficients with pitch-angle, L and energy dependence. In this talk we discuss the potential implications for the radial diffusion rates as currently estimated.
Clustering as a tool for identifying drought-prone regions: A Swedish example
Authors: Teutschbein Claudia , Todorovic Andrijana , Grabs Thomas
Published: February 2023

The increasing availability of large data sets has fuelled the application of clustering approaches for discovering and interpreting spatio-temporal patterns in hydroclimatic data. Clustering can be particularly powerful for grouping catchments that span across various climate zones or hydrologic regimes into homogeneous clusters of similar hydrological or climatic behavior.Here, we provide a practical example of how clustering can facilitate comprehensive analyses of streamflow drought characteristics across 50 Swedish catchments spanning three climate zones and ranging from snow-melt driven streamflow regimes in the North to rainfall-driven regimes in the South. To this end, the k-means clustering was applied to generate homogeneous clusters of catchments based on their similarity in streamflow anomalies (detected by using the standardized streamflow index) over the past 60 years. Five geographically distinct regions emerged from the clustering, linking the streamflow anomalies to the hydroclimatic conditions (following the north-south and elevation gradients), and to landscape characteristics, which strongly affect streamflow-generating processes at the catchment scale. Each cluster also featured – in line with its geographical location – a distinct hydrological regime.Facilitated by the clustering, a clear north-south gradient emerged for many of the analysed drought statistics, including, e.g., drought duration, annual number of drought days and number of drought days in spring and summer, as well as standardized deficit volumes. Similarly, trends and changes in streamflow anomalies over the past 60 years also varied across clusters, with clusters in northern Sweden exhibiting wetting trends and clusters in southern Sweden drying trends.This case study serves as an illustration of how clustering can be a valuable tool for improving our understanding and potential prediction of hydrological processes. Clustering enabled us to identify drought-prone areas and illuminated various drought behaviors, prevailing drought typologies, and seasonal differences that can be linked to the underlying streamflow regimes. 