bluuebunny/crossref_metadata_2025 huggingface dataset:
3D scattering and absorption imaging of the Pollino seismic gap (Italy)
Authors: Napolitano Ferdinando , Amoroso Ortensia , De Siena Luca , Gabrielli Simona , Capuano Paolo
Published: February 2023

The Pollino area, one of the largest seismic gaps in Italy, has been struck between 2010 and 2014 by a long-lasting seismic sequence. More than 10,000 small-to-medium earthquakes followed a temporal evolution typical of a seismic swarm and, to a lesser extent, of  aftershocks following the two strongest events: a ML 4.3 on 28 May 2012 and a ML 5.0 on 25 October 2012. A delay of almost 4 months separated the two main events, with the first event occurring two years after the beginning of the swarm. A slow slip event began about three months before the strongest earthquake. High VP and high VP/VS values have been found in the swarm area, where clusters of events of similar waveforms have been identified in recent works. The distribution of seismicity has been driven by pore fluid pressure diffusion with relatively low diffusivity value.The present work aims to provide the first 3D images of scattering and absorption of the Pollino area at different frequency bands, measured through peak delay mapping and coda-attenuation tomography, respectively. We collected 870 earthquakes from the 2010 - 2014 seismic sequence and surrounding area, characterized by ML > 1.7, already applied in a recent tomographic work. We used the manual P-wave pickings of the waveforms to compute the peak delay as the lag between the P-wave onset and the maximum of the envelope. Instead, the coda window has been fixed for the entire dataset at 30 seconds after the origin time of the earthquakes, lasting for 15 seconds. This late lapse time allows us to interpret Qc-1 as a marker of the absorption.The preliminary results show a high scattering anomaly characterizing the seismogenic volume of the sequence and the newly identified faults surrounding the focal area. A strong scattering contrast has been identified south of the ML 5.0 plane. This contrast is likely related to the presence of a segment of the Pollino Fault that acts as a barrier for the Southern propagation of the sequence. High attenuation anomalies in areas already marked by high VP and high VP/VS confirm the role that fluids played in this complex sequence. These results, together with the recent outcomes, could give more insights about the seismic hazard of this complex area.This work was supported by the PRIN-2017 MATISSE project (no. 20177EPPN2), funded by the Ministry of Education and Research.
Forecasting the risk of vector-borne diseases at different time scales: an overview of the CLIMate SEnsitive DISease (CLIMSEDIS) Forecasting Tool project for the Horn of Africa
Authors: Caminade Cyril , Morse Andrew P. , Fevre Eric M. , Mor Siobhan , Baylis Mathew , Kelly-Hope Louise
Published: February 2023

Vector-borne diseases are transmitted by a range of arthropod insects that are climate sensitive. Arthropods are ectothermic; hence air temperature has a significant impact on their biting and development rates. In addition, higher temperatures shorten the extrinsic incubation period of pathogens, namely the time required for an insect vector to become infectious once it has been infected. Rainfall also creates suitable conditions for breeding sites. The latest IPCC-AR6 report unequivocally concluded that recent climate change already had an impact on the distribution of important human and animal diseases and their vectors. For example, dengue is now transmitted in temperate regions of Europe, and malaria vectors are now found at higher altitudes and latitudes in the Tropics. Different streams of climate forecasts, ranging from short range numerical weather prediction (NWP) models to seasonal forecasting systems, to future climate change ensembles can be used to forecast the risk posed by key vector-borne diseases at different time scales.  This work will first introduce vector-borne disease forecasting system prototypes developed for different time scales and applications. Three examples will be presented; first a NWP driven model to forecast the risk of the animal disease Bluetongue in the UK, second the skill of the Liverpool malaria model simulations driven by seasonal forecasts in Botswana, and third the impact of RCP-SSP climate change scenarios on the risk posed by dengue and malaria at global scale. In addition, the use of mathematical disease models in anticipating disease risk will be presented, highlighting the limited uptake by policy makers. To bridge the academic/policy making gap, novel participatory approaches which include all actors need to be developed.The CLIMate SEnsitive DISease Forecasting Tool (CLIMSEDIS) project aims to bridge that gap. The overall aim of CLIMSEDIS is to develop and build capacity in the use of an innovative user-friendly digital tool. CLIMSEDIS will allow end-user stakeholders to utilise forecasts and delineate sub-national risk of multiple climate sensitive diseases to inform timely and targeted intervention strategies in eight countries across the Horn of Africa. Disease prioritization exercise, scoping reviews and interactive workshops with stakeholders will be carried out. The final deliverable will consist in a web-based portal and a phone application that will be used, maintained, and developed further by key African regional partners. A presentation of the CLIMSEDIS project phases and its overall strategy will be presented. 
Cross-verification of local inventory CO2 emissions and tall tower eddy covariance fluxes measurements in Vienna
Authors: Fasano Enrichetta , Matthews Bradley , Vuolo Francesco , Schume Helmut
Published: February 2023

Curbing carbon dioxide (CO2) emissions from cities is critical for climate change mitigation given the substantial urban contribution to global anthropogenic greenhouse gas (GHG) emissions. Despite relatively robust inventory estimates of total urban CO2 emissions at regional and global scales, emission inventories at the level of individual cities can be very uncertain due to unavailability of input data and/or uncertainties in downscaling aggregated statistics or emissions. A growing field of research is thus investigating the application of atmospheric measurement and modelling to support CO2 emissions monitoring in cities. Here we present ongoing research comparing local emission inventories of the city of Vienna, Austria with tall tower eddy covariance measurements of CO2 fluxes. In contrast to inverse modelling methods, eddy covariance allows net surface emissions to be directly inferred from the  measured vertical turbulent fluxes in the surface layer above cities. For this analysis local emission inventories were processed with external data (e.g., measurements of local traffic counts and air temperature, proxies from literature) to produce temporally-resolved emissions maps (hour-hectare resolution) from the annual, aggregate inventory estimates for the years 2018 to 2020. For the comparison with the flux measurements, these emission maps were cropped after overlapping these layers with an average flux footprint calculated from flux measurements made during northwesterly flows, when the most densely inhabited districts of the city were sampled. On an annual scale, the flux measurements and inventory estimates of total CO2 emissions agree well with one another. Furthermore, encouraging results were obtained when comparing annual space-heating and traffic emissions from the inventories with respective estimates derived from regression analyses of the eddy fluxes against local air temperature and traffic counts. At sub-annual scales, seasonal and hourly divergences between the inventories and the eddy covariance measurements were indicative of boundary layer dynamics (decoupling between turbulent exchange and fluxes at the surface) as well as a seasonal influence of urban vegetation on net CO2 fluxes.
Numerical investigation of tidal forcing on the stability of bifurcations
Authors: Durante Lorenzo , Bolla Pittaluga Michele , Tambroni Nicoletta
Published: February 2023

River bifurcations are ubiquitous features of both gravel-bed and sand-bed fluvial systems, including braided networks, anabranches and deltas. As such, their morphology and development shape fluvial plains and deltas, dictating flood-prone areas as well as land loss and land gain. In this regard, bifurcations worldwide are often found unstable to any perturbation of their current state, leading to highly asymmetric discharge partitions between the branches or ultimately to the complete closure of one of them. However, in tide‐influenced deltas, it has been observed that bifurcations tend to exhibit more stable branches keeping all channels active. Therefore, although the morphodynamic equilibrium of bifurcations is strongly affected by the characteristics of the upstream channel, only lately some effort has been put into studying the action exerted by external forcings in the downstream channels. Ragno et al. (2020), inserting small-amplitude tides in the analytical model of Bolla Pittaluga et al. (2015) of river bifurcations, managed to prove that even small-amplitude tides have a stabilizing effect. In this regard, we aim at extending their analysis to the case of finite amplitude tidal forcing through a series of numerical investigations. Factors such as the length of the downstream channels or different tidal ranges are studied in order to define their influence on the evolution of bifurcations. Results show that present analytical theories are able to reproduce fairly well the increase of stability in small amplitude tidal systems, while they tend to overestimate the stability of bifurcations in higher tidal range ones. Numerical simulations show that, even when a branch gets dry during low tide due to the step formed at the bifurcation node, it might still receive river flow in high tides keeping the typical estuarine environment alive. However, increasing the tidal range to finite amplitudes, estuarine bifurcations are found to be less stable than their pure fluvial counterparts.
Near-surface vs. sub-surface soil moisture impacts on vegetation functioning
Authors: Khanal Prajwal , van Dijke Anne Hoek , Zeng Yijan , Orth René
Published: February 2023

Soil water availability is a critical requirement for vegetation functioning in a water-limited regime. Vegetation takes up water from varying soil depths depending on their rooting location and soil moisture availability. The uptake depth varies spatially across climate regimes and vegetation types and temporally between seasons. Yet, a scientific consensus on the global relevance of near-surface and sub-surface soil moisture for vegetation functioning is still lacking and is the focus of this study. In particular, we calculate the correlation between the Near-Infrared Reflectance of Vegetation (NIRv) with both satellite-derived near-surface soil moisture from ESA-CCI and terrestrial water storage from GRACE. This is done globally and with monthly data during the growing season at each grid cell and accounting for the confounding effects of temperature and radiation. We analyze how these correlations vary spatially across varying vegetation types and climatic regimes, and temporally between all growing season months and particularly dry months. Finally, we repeat the analyses using Sun-induced fluorescence (SIF) data instead of NIRv. We find that NIRv and SIF correlate more strongly with near-surface soil moisture compared to terrestrial water storage in semi-arid regions with low tree cover. This suggests that the vegetation preferentially takes up water from near-surface soil moisture whenever available to meet its transpiration demand.   In contrast, in regions with more tree cover and in drier regions, the correlation with terrestrial water storage is comparable to or even higher than with near-surface soil moisture. This indicates that trees can make use of their deep rooting systems to access deeper soil moisture resources, similar to vegetation in arid regions. In particularly dry months, correlations with near-surface soil moisture increase while this is even more the case with terrestrial water storage, highlighting the relevance of deeper water resources during rain-scarce periods.Overall, while direct observations of sub-surface soil moisture are scarce, this study employs different satellite-based data streams in order to estimate the relevance of near-surface versus sub-surface soil moisture for vegetation functioning. This can inform the representation of vegetation-water interactions in land surface models to support more accurate climate change projections. 
Unraveling the Transcrustal Magmatic Mush and Geothermal Systems of Aluto and Corbetti Volcano in the Main Ethiopian Rift using Magnetotellurics
Authors: Dambly Luise , Samrock Friedemann , Grayver Alexander , Saar Martin
Published: February 2023

Active continental rifting in Ethiopia has led to formation of numerous volcanoes and geothermal systems with associated socio-economic potential for generating clean energy.Aluto and Corbetti are two silicic volcanoes in the Central Main Ethiopian Rift (CMER) that have been closely examined. Past studies provided insights into their formation in the extensional magma-tectonic context of the CMER, into causes of volcanic unrest and surface deformation and seismic activity, as well as their geothermal systems. However, many aspects about the structure of the volcanoes’ underlying transcrustal magmatic system remained unanswered.Here, we present new 3-D electrical conductivity models of these volcanoes, obtained from inversions of magnetotelluric (MT) data, providing the most detailed images of the associated magmatic and geothermal systems across multiple scales so far.The models from Aluto and Corbetti provide evidence for several hypothesized properties of the associated magmatic systems. The cross-rift model, enclosing Aluto, shows that the volcano’s lower crustal melt source, west of the rift axis, also feeds volcanos in the western part of the rift, which has been debated in the past.  Our Corbetti model confirms the existence of a shallow magmatic intrusion, as it has been modelled from InSAR and gravimetry studies.We estimate thermodynamically constrained melt fractions and interpret geothermal flow structures. The inferred melt fractions indicate crystalline magmatic mush systems in rheological lock-up, where melt is extracted slowly through buoyancy processes, while mechanical trapping explains the observed compositional gaps.
Mobile Air Quality monitoring with daily commuters in Rotterdam
Authors: Van Poppel Martine , Hofman Jelle , Peters Jan , Hoek Gerard , Kerckhoffs Jules , Willers Saskia , Özdemir Emre
Published: February 2023

Air pollution is the fourth cause of premature mortality (HEI, 2020) and in Europe, more than 0.3 million premature deaths are due to air pollution (EEA, 2021). In urban environments, people are exposed to a complex mixture of air pollutants with a large spatial variability. However, highly spatially resolved measurement data on air pollutants is lacking. These fine-grained data is needed to correctly assess personal exposure to air pollution for epidemiolocal studies and to support air quality management scenarios.Within RI-URBANS different innovative approaches to get insights into novel air quality parameters, source contributions, exposure to air pollution and associated health effects will be developed and tested. One of the approaches relies on mobile measurements with citizens to derive spatial air pollution maps. Mobile measurements can contribute to understand spatial variability of short-living constituents of air pollution from a diversity of pollution sources.The monitoring campaign is performed with volunteers, who are all employees of DCMR or the city of Rotterdam. They are asked to measure during their daily bicycle commutes. Before the measurement campaign, a training session was organized for the volunteers. Measurements were performed in winter (November 2022 – February 2023) and will be repeated in spring 2023.Measurements are based on the airQmap approach; more information on the approach and previous studies can be found on https://www.airQmap.com. Measurements of Black Carbon (BC) are performed using a microaethalometer (microAeth®, AE51, AethLabs) and a GPS.  BC is measured at 1s temporal resolution and a flow rate of 150 mL min-1. To reduce the noise in BC measurements, the ONA (Optimized Noise-reduction Averaging, Hagler et al., 2011) algorithm was used with an attenuation threshold of 0.05. The geo-tagged measurements were aggregated (trimmed mean) and attributed to fixed points 20 m apart from each other along the cycling route.The dataset will be used to test different data processing techniques (a.o. temporal aggregation, background correction approaches) to construct representative BC maps.  The collected spatiotemporal BC measurements will be analysed to identify main sources of BC in the area. The pilot study will result in guidance on best practices for mobile air quality monitoring involving citizens.This paper will present the results of the winter campaign.____________________EEA, 2021. HI of Air Pollution in EUHagler, G.S., Yelverton, T.L., Vedantham, R., Hansen, A.D., Turner, J.R., 2011. Postprocessing method to reduce noise while preserving high time resolution in Aethalometer real-time black carbon data. Aerosol Air Qual. Res. 11, 539-546.HEI, 2020. State of Global Air
Modelling the ocean circulation of the mid-Cretaceous using the Community Earth System Model (iCESM1.2) and the internal wave mixing parameterization IDEMIX
Authors: Kattamuri Siva , Paul André , Pollmann Friederike , Schulz Michael
Published: February 2023

The mid-Cretaceous (~90 Ma) was a natural case of the greenhouse climate state of the earth. Enhanced volcanic activity contributed to the higher atmospheric concentration of CO2. The continental configuration was different and the global mean sea level was around 160m higher compared to the present day.  Black shales from this period's marine sediments indicate a near-anoxic deep-ocean environment. This project hypothesizes that redistribution of tidal energy dissipation from the open ocean to the large continental shelf areas reduced the energy available for mixing in the deep ocean. The objective is to investigate the effect of climate parameters and geographical configuration on ocean circulation by using the energetically consistent internal wave mixing parameterization IDEMIX in the fully coupled Earth System Model iCESM1.2. As part of the second phase of the CRC - Transregio 181, this project aims to make the Earth system model energetically consistent for improved climate projections.The paleo-topography/bathymetry of the mid-Cretaceous is adopted from Scotese and Wright’s PALEOMAP (2018) project. The paleo-vegetation distribution is taken from Sewall’s (2007) mid-Cretaceous boundary conditions. The necessary boundary conditions and the climate-forcing files for the individual component models are prepared by using the Paleoclimate ToolKit of the CESM documentation. This mid-Cretaceous setup is spun-up with present-day trace gas concentrations for over 1000 model years. Constant tidal mixing coefficients are used in this spin-up. The first results from this spin-up indicate deep-water formation in the mid-latitudes in the Northern Hemisphere. From the equilibrium state of the spin-up, trace gas concentrations of the mid-Cretaceous will be input in the model. The ocean circulation will then be simulated with the internal wave mixing schemes KPP and IDEMIX for a comparative study. We expect improved results for deep-water formation sites and deep-ocean oxygenation with the IDEMIX parameterization.
Towards using multi-dimensional structures in climate variables to detect anthropogenic changes
Authors: Egli Marius , Sippel Sebastian , Humphrey Vincent , Knutti Reto
Published: February 2023

Precipitation (P) and evapotranspiration (ET) play a crucial role in the water cycle and have a significant impact on water resources and the energy balance of the Earth's surface. However, it remains a challenge, in particular on regional scales, to detect changes in hydrological variables and attribute them to anthropogenic or natural influences. Traditional studies that aim to detect or attribute changes in atmospheric variables often consider only a single variable at a time. This makes detecting changes in hydrological variables challenging due to large internal variability, the lack of long-term observational coverage and partly poor mechanistic understanding of land-atmosphere coupling processes in a changing climate. However, because P and ET are related to various other atmospheric variables, such as temperature, humidity, and sea level pressure, the detection of anthropogenic influences may be conducted in principle within a broader multivariate space. Here, we aim at exploiting multivariate relationships to more robustly detect anthropogenic changes to the hydrological cycle at the regional or up to continental scale. We train statistical models from coupled Earth system models to learn the relationships between relatively well observed variables and more poorly observed ones, like P and ET. We demonstrate that such models can predict and extract patterns of forced change in P and ET, albeit somewhat contingent on the realism of the simulation of the Earth system model. The main advantage is that the method does not rely on sparse observations of P and ET, and instead relies on covariates which are more abundantly and reliably observed. We demonstrate the effectiveness of this approach in a climate-model-as-truth framework, showing that it can capture a wide range of possible hydrological responses produced by the different climate models. We also apply the statistical model to observations to identify forced changes in P and ET that have already occurred. For example, we see an increase in ET in the northern hemisphere likely induced by a reduction in aerosol emissions. Our results show that this method can infer changes in P and ET that may have taken place, in principle even without the need for direct observations of those variables and can provide constrained projections of future water resources and energy balance.
Rapid Estimation of Earthquake Disaster Loss Based on Physical Simulation and Empirical Statistics—A Case Study of the 2021 Yangbi Earthquake
Authors: Li Yilong , Zhang Zhenguo , Wang Wenqiang , Xin Danhua
Published: February 2023

At present, seismic prediction technology is still not available. Scientific decision-making and rescue after an earthquake are the main means of mitigating the immediate consequences of earthquake disasters. If earthquake emergency response level, fatalities, and economic losses can be estimated rapidly and quantitatively, this estimation will provide timely, scientific guidance to government organizations and relevant institutions to make decisions on earthquake relief and resource allocation, thereby reducing potential losses and more conducive to the implementation of social activities such as post-disaster reconstruction and reinsurance. To achieve this goal, a rapid earthquake disaster loss estimation method is proposed herein, based on a combination of physical simulations and empirical statistics. The numerical approach was based on the three-dimensional curved grid finite difference method (CG-FDM), implemented for graphics processing unit (GPU) architecture, to rapidly simulate the entire physical propagation of the seismic wavefield from the source to the surface for a large-scale natural earthquake over a 3-D undulating terrain. Simulated seismic intensity data were used as input for the earthquake disaster loss estimation model to estimate the fatality, economic loss, and emergency response level. The estimation model was developed by regression analysis of the data on human loss, economic loss, intensity distribution, and population exposure from the composite damaging earthquake catalog. We used the 2021 Ms 6.4 Yangbi earthquake as a study case to provide estimated results. The number of fatalities estimated by the model was in the range of 0–10 (five expected fatalities). The most probable economic loss range was 1–10 billion RMB (the expected economic loss was 4.862 billion RMB). Therefore, Level IV earthquake emergency response plan should have been activated (the government actually overestimated the damage and activated a Level II emergency response plan). The local government finally reported three deaths and 3.32 billion RMB economic losses during this earthquake, which is consistent with the model predictions.
Spatial variation of ice crystal fabric and implications of anisotropic flow in the Northeast Greenland Ice Stream
Authors: Gerber Tamara , Eisen Olaf ,   NEGIS community
Published: February 2023

Anisotropic crystal fabrics in ice sheets develop as a consequence of deformation and hence record information of past ice flow. Simultaneously, the fabric affects the present-day bulk mechanical properties of glacier ice because the susceptibility of ice crystals to deformation is highly anisotropic. This is particularly relevant in dynamic areas such as fast-flowing glaciers and ice streams, where the formation of strong fabrics might play a critical role in facilitating ice flow. Anisotropy is ignored in most state-of-the-art ice sheet models, and while its importance has long been recognized, accounting for fabric evolution and its impact on the ice viscosity has only recently become feasible. Both the application of such models to ice streams and their verification through in-situ observations are still rare. We present an extensive dataset of fabric anisotropy derived from ground-based and air-borne radar data, covering approximately 24,000 km2 of the Northeast Greenland Ice Stream onset region. Our methods yield the horizontal anisotropy and are based on travel time anisotropy as well as birefringence-induced power modulation of radar signals. These methods complement each other and show good agreement. We compare the in-situ observations with the results obtained from a fabric-evolution model employed along flow line bundles in the ice stream onset to discuss the fabric in light of past flow history and its significance for the current flow mechanics of the ice stream. 
Diagnosing atmospheric persistence for heatwaves and in extended range forecasts
Authors: Holmberg Emma , Messori Gabriele , Caballero Rodrigo , Tietsche Steffen , Faranda Davide
Published: February 2023

Extreme events can cause severe disruption to society on many levels, and the ability to forecast these events represents a significant step towards the ability to reduce their impacts. Anomalously persistent atmospheric configurations are typically regarded to be strongly linked with temperature extremes in Europe, however, traditional methods of analysing atmospheric persistence lack a mathematically well-grounded definition. Furthermore, we are not aware of a metric which allows for quantification of instantaneous atmospheric persistence for forecasts for either an individual ensemble member or a deterministic forecast. We aim to help refine the definition of atmospheric persistence by presenting a mathematically well-grounded definition of persistence, which can potentially also be applied in a forecasting environment. We examine the link between the extremal index, an indicator for atmospheric persistence based on dynamical systems theory, and warm temperature extremes in several regions of Europe. We then consider the applicability of this technique to forecast data, in particular ECMWF extended range reforecast data, discussing its potential value as an additional forecast evaluation metric.
Water mass transformation following instability in the mixed layer of the East Greenland Current
Authors: Goldsworth Fraser , Le Bras Isabela , Johnson Helen , Marshall David
Published: February 2023

Observations show that strong southerly winds over the Irminger Sea can excite symmetric instability in the East Greenland Current, resulting in the generation of a low potential vorticity layer below the convectively mixed layer (Le Bras et al., 2022). The role of these downfront wind events on the formation of dense waters is not yet well understood.Using an ensemble of ultra-high resolution models (25 m in the horizontal)  we show that the low potential vorticity layer is virtually indistinguishable from the convectively mixed layer, implying the absence of symmetric instability in coarse models may lead to underestimates in the mixed layer depth and baroclinicity of the East Greenland Current. We explore the hypothesis that symmetric instability acts as the short time-scale response of the current to these southerly wind events and pre-conditions the mixed layer, making it more susceptible to baroclinic instability over longer time-scales. We then investigate whether baroclinic eddy activity is enhanced following these wind events and examine the implications of this on lateral and diapycnal mixing, including by calculating water mass transformation rates.
Assessing carbon mineralization using an integrated approach at the Nesjavellir geothermal field, Iceland
Authors: Clark Deirdre , Marteinsson Kjartan , Þorgilsson Gunnar , Galeczka Iwona , Helgadóttir Helga , Snæbjörnsdóttir Sandra , Sigfusson Bergur , Gunnarsdóttir Sveinborg
Published: February 2023

The Nesjavellir high-temperature geothermal field in Iceland was chosen as part of the GECO H2020 project to further demonstrate the Carbfix method of carbon mineralization. In this method, geothermal power plant emissions of CO2 and H2S are captured using condensed steam, and subsequently co-injected with separated geothermal water into the subsurface where they mineralize in the form of carbonate and sulfide minerals. This technology has already been successfully shown to be a safe and cost-effective approach to reduce gas emissions from the nearby Hellisheiði geothermal power plant in SW Iceland.An integration of geology, reservoir and geochemical models were used to evaluate the future injection of CO2 and H2S at the Nesjavellir site. These models include reservoir parameters such as the relative permeability and porosity of different stratigraphic layers as well as the locations of feedzones. Tracer tests and well temperature and pressure logs were used to calibrate single porosity and dual porosity TOUGH2 flow models. A 1-D flow reactive transport model was then created using TOUGHREACT and the parameters from the flow models and calibrated using chemical compositions of the reservoir background fluid and separated water, the proposed gas injection fluid chemistry and available bulk rock chemistry and lithological data from borehole reports. Results from this integrated approach offer possible controls on the flow, impacts of the CO2-H2S injection, and estimate the potential storage capacity of carbon mineralization within the Nesjavellir geothermal reservoir.
A statistical gap filling model for methane fluxes over an urban area in the Alps
Authors: Stichaner Michael , Lamprecht Christian , Graus Martin , Goded Ignacio , Jensen Niels , Karl Thomas
Published: February 2023

There is consensus that climate change is mostly driven by anthropogenic greenhouse gas emissions. In addition to CO2 emissions, which have been the subject of public debate for a long time, increased awareness of methane (CH4) emissions has developed in recent years. CH4 is considered the 2nd most important contributor to radiative forcing, making it the most important non-CO2 greenhouse gas.Due to the relatively short lifetime of the gas in the  atmosphere compared to CO2, the reduction of methane emissions can lead to a climate benefit on relatively short time horizons. In order to effectively reduce emissions, the polluters must be better understood and recognized. Here, we combine methane eddy covariance observations in combination with a variety of other trace gases and meteorological parameters that have been recorded since August 2020 in an Alpine city (Innsbruck, Austria) to investigate urban methane emissions. For an accurate comparison with bottom-up emission inventories we test different gap-filling methods with the help of meteorological parameters as well as other tracer fluxes, such as NO, NO2, or CO2. In order to quantify methane emissions in urban areas as annual totals, a complete, gap-free flux dataset is desired. We have developed different statistical gap filling models which are able to predict CH4 fluxes at the study location. The method is based on a boosted regression tree model with a variety of meteorological and astronomical parameters, as well as other trace gas fluxes serving as input. Different combinations of these input parameters are tested for accuracy of their prediction. Contrasting other gap filling methods, used over uninhabited areas, adding gases like CO2 or NO can serve as important additional predictors, because sectors related to combustion processes are considered as important contributors to CH4 emissions.  In this presentation we discuss CH4 flux measurements performed during the last 2,5 years over an urban area, and highlight first results on the performance of the developed gap filling models. 
Did the dynamo cease during the Ediacaran Period prior to inner core nucleation?
Authors: Zhou Tinghong , Tarduno John , Kodama Kenneth , Cottrell Rory , Bono Richard
Published: February 2023

Models and paleointensity data continue to consistently point to the Ediacaran Period as the most likely time for the onset of inner core nucleation (ICN). The geodynamo models of Driscoll (2016) and Driscoll and Davies (2022) predict a weak field state, where core kinetic energy exceeds magnetic energy, prior to ICN. The paleomagnetic record of the Ediacaran Period shows a hyper-reversal frequency and unusually high secular variation. But the most telling characteristic of the Ediacaran magnetic field that suggests the dynamo approached the weak field state is its time-averaged ultralow paleointensity, more than 10 times weaker than today (Bono et al., 2019). The field subsequently regained strength in the early Cambrian (Zhou et al., 2022), consistent with Ediacaran ICN. Here, we investigate the possibility that the magnetic field may have ceased completely for some part of the Ediacaran Period. We report new field strength values from whole rocks that are less than 1-2 microTesla. These values are amongst the lowest terrestrial fields ever recorded, heightening the possibility of environmental effects due to the weakened magnetosphere that may have in turn influenced biotic evolution. But even these ultralow field values may overestimate the true ambient field strength because of subsequent thermal viscous magnetic overprints carried by nonideal magnetic carriers in whole rocks. We will discuss our efforts to use single crystal paleointensity methods to isolate ideal magnetic carriers to resolve this question.
Using Seismic Methods to Monitor Bedload Transport Along a Desert Environment Ephemeral Tributary
Authors: Bilek Susan , McLaughlin J. Mitchell , Cadol Daniel , Laronne Jonathan
Published: February 2023

Use of seismic monitoring and data analysis techniques in recent years have allowed for improved understanding of several shallow earth processes, such as glacial motion, subsurface water flow, and bedload transport. Early applications using seismic data collected at high energy alpine rivers suggest that seismic energy within certain frequency bands is linked to bedload discharge.  However, study of other river systems have been more limited, even though some of these systems, such as ephemeral streams in arid environments, transport large quantities of sediment during short-lived flash flood events.  Here we present seismic and hydrologic data collected in a unique sediment observatory within an ephemeral tributary to the Rio Grande River, in the desert southwest of the U.S., combining dense seismic observations with a variety of in-channel bedload and water monitoring measurements. We have seismic records for more than a dozen floods ranging in depth from a few centimeters to over one meter, encompassing bedload flux as high as 12 kg s-1 m-1, two orders of magnitude higher than in most perennial settings. Our efforts to date focus on identifying the noise sources within the seismic record, characterization of the seismic properties of the site, and determining the seismic frequency ranges best correlated with the automatically measured bedload flux. Within the 30-80 Hz frequency range, we find a linear relationship between seismic power and bedload flux. We hypothesize that variations in linear fit statistics between flood events are due to varying bedload grain size distributions and in-channel morphological changes.
Power spectrum estimation for extreme events data
Authors: Marwan Norbert , Braun Tobias
Published: February 2023

The estimation of power spectral density (PSD) of time series is an important task in many quantitative scientific disciplines. However, the estimation of PSD from discrete data, such as extreme event series is challenging. We present a novel approach for the estimation of a PSD of discrete data. Combining the edit distance metric with the Wiener-Khinchin theorem provides a simple yet powerful PSD analysis for discrete time series (e.g., extreme events). This method works directly with the event time series without interpolation. We demonstrate the method's potential on some prototypical examples and on event sequences of atmospheric rivers (AR), narrow filaments of extensive water vapor transport in the lower troposphere. Considering the spatial-temporal event series of ARs over Europe, we investigate the presence of a seasonal cycle as well as periodicities in the multi-annual range for specific regions, likely related to the North-Atlantic Oscillation (NAO).
The promotion of decomposition of root-derived biomass by warming is depth dependent in a temperate forest
Authors: Sun Binyan , Zosso Cyrill , Wiesenberg Guido , Torn Margaret , Schmidt Michael
Published: February 2023

IPCC climate scenarios (RCP 8.5) suggest 4°C warming until 2100, which could accelerate soil carbon loss, greenhouse gas release, and further promote global warming. Despite low carbon concentrations, subsoils (> 30 cm) store more than half of the total global soil organic carbon stocks. However, it remains largely unknown, how deep soil carbon will respond to warming and how root-derived carbon as a potential recalcitrant part of soil carbon could contribute to carbon stabilization in subsoils. After three years of root-litter incubation, we aim to i) quantify decomposition of root-litter at different depths in a +4°C warming field experiment, ii) assess whether specific plant polymers will degrade differently in warmed and control plots, iii) identify decomposition products of plant biomass remaining.In a field experiment in a temperate forest (Blodgett Forest, Sierra Nevada, CA, USA), 13C labelled root-litter was incubated at three soil depths (10-14, 45-49, 85-89 cm) in soil cores for one and three years. For bulk soil, we measured carbon and nitrogen concentrations, and δ13C isotope composition. For individual molecular analysis, we quantified and determined the δ13C isotope composition of microbial biomarkers (PLFA), and plant-derived biomarkers (mainly suberin monomers released after base hydrolysis). We also explored suberin monomers as biomarkers for root-derived biomass (here ω-hydroxy fatty acids).We observed the following: i) In the plots without additional labelled root-litter, warming led to heavier suberin biomarker δ 13C values compared with control plots, especially in the topsoils. This indicates a more advanced degradation due to warming. ii) In plots with added labelled root-litter, bulk soil δ13C values become heavier with soil depth. For individual suberin markers, we find less excess 13C with warming especially in topsoils, indicating more advanced decomposition in topsoils with warming. This advanced decomposition was not found in subsoils.We conclude that the decomposition of root organic matter is depth dependent, and warming promotes the loss of suberin in topsoils, which contradicts the present assumption of suberin as a slowly degrading part of plant-derived organic matter.
Geodiversity assessment of Shkodra Region, Albania
Authors: Kraja Drisela , Albert Gáspár
Published: February 2023

Shkodra Region, with an area of 953.64 km2, is located in north-western part of Albania. It is one of the richest geosite region of Albania, starting from the Lake Shkodra as the largest lake in the Balkan Peninsula, through the Adriatic sea shore, and up to the North Albanian Alps with a height of 2694 m and several glacial morphological features. In the region there are several caves in the mountains, three main rivers: Buna, Drini and Kiri, and nature reserves: the Theth National Park, and the Maranai Park. Due to its geological position in the Eastern Alpine Mediterranean Belt, there are diverse geological formations in Shkodra Region. The Mesozoic marine sediments (Triassic dolomite, limestones and shales, Jurassic limestone, marl, and Cretaceous carbonates) and Paleogene flysch make up a significant part of the surface geology, but Late Permian and younger Cenozoic sediments are also present in the area. Such a variety of geological, geomorphological, pedological and hydrological features can be best described in terms of geodiversity.This study aims to present a quantitative assessment of geodiversity for the Shkodra Region. The geodiversity indexes were calculated using different data, such as MERIT Hydro Digital Elevation Model, existing geological and soil maps, and spatial databases such as the EGDI (European Geological Data Infrastructure). The method followed is based on Pereira et al. (2013) and Pál & Albert (2021).Why is it important to present Shkodra's geodiversity? The area is a tourist destination due to it’s natural values as well as it’s cultural heritage like Rozafa Castle with a 4000 - years old history and Illyrian origins, Historical Museum of Shkodra, Marubi National Museum of Photography, etc. The abundance of cultural and natural values of an area make it suitable to geopark establishment which can help the local economy in a sustainable way. Although the establishment of such an park in the area was already recommended (Serjani A., 2020), the important step of scientific assessment was not executed. This assessment is the first to demonstrate the complex diversity of geoscientific features in the Shkodra Region. ReferencesPál, M., & Albert, G. (2021). Refinement proposals for geodiversity assessment—a case study in the Bakony–Balaton UNESCO Global Geopark, Hungary. ISPRS International Journal of Geo-Information, 10(8). https://doi.org/10.3390/ijgi10080566Pereira, D. I., Pereira, P., Brilha, J., & Santos, L. (2013). Geodiversity assessment of Paraná State (Brazil): An innovative approach. Environmental Management, 52(3), 541–552. https://doi.org/10.1007/s00267-013-0100-2Serjani, A. (2020). Geoheritage and Geotourism in Albania. In The Geotourism Industry in the 21st Century (pp. 169-188). Apple Academic Press.
Effects of soil carbon management and drought on grassland root systems and soil microbial communities
Authors: Guasconi Daniela , Cousins Sara , Fransson Petra , Manzoni Stefano , Hugelius Gustaf
Published: February 2023

Grasslands are often water-limited ecosystems with high belowground carbon allocation. Their root systems and soil microbial communities play an important role in regulating the soil carbon pool, and properly managed, grasslands may contribute to climate change mitigation via sequestration of carbon (C) in soils. However, it is still uncertain how roots and microbial communities are affected by drought and changes in precipitation patterns in combination with management for soil C sequestration. Expected longer dry periods and more intense precipitation events will evoke soil microbial responses that may feed-back on soil carbon storage.We set up an experiment in southern Sweden in 2019 to investigate the response of belowground biodiversity to chronic drought (via partial rainfall exclusion) and carbon amendments in the form of a compost addition. We sampled belowground plant biomass, root traits and soil microbial communities from two grasslands with different land use history and over several depths. We extracted and sequenced fungal and bacterial DNA using metabarcoding, and carried out vegetation inventories at the sites - including plant biomass and relative abundance of plant functional types. At the same time, we monitored changes in soil moisture and soil organic matter from topsoil to deep soil, to assess the effect of the treatments throughout the soil profile.After three years of treatment, we expected to observe changes in the root systems and soil microbiota in response to decreased precipitation, as well as interactions between soil moisture and the organic matter added through the compost amendment. In addition, we expected to see shifts in the composition of fungal functional groups involved in organic matter decomposition and mycorrhizal symbionts limited to the rooting zone. The analyses suggest that changes in soil C and soil moisture affect only the topsoil. While overall root biomass did not change significantly in the treatment plots over the course of the experiment, we observed a slight increase in rooting depth and root mass density and a decrease in fine root length under drought. The results of this study will contribute to assess ecosystem responses to drought, and to evaluate the potential for soil carbon sequestration in grasslands and its possible impacts on belowground biodiversity.
Performance of a Parsimonious Phosphorus Model (SimplyP) in Two Contrasting Agricultural Catchments in Ireland
Authors: Hawtree Daniel , Galloway Jason , Zurovec Ognjen , Jackson-Blake Leah , Norling Magnus , Mellander Per-Erik
Published: February 2023

The Agricultural Catchment Program (ACP) has collected over a decade’s worth of high frequency data for a number of hydrologic and chemical indicators at agricultural catchments around the Republic of Ireland. This dataset provides an excellent foundation for conducting robust modelling studies assessing long term hydrochemical dynamics in agricultural sites, within the context of EU regulations around the protection of water quality.To examine the risks of phosphorus (P) export from agricultural catchment in this context, the parsimonious phosphorus model SimplyP was applied to two ACP study sites. These sites are in close proximity and are of similar size to each other but have contrasting physical characteristics and hydrochemical dynamics. Site “A” is dominated by grasslands with heavy soils and is P export risky, while site “B” is primarily arable land-use on lighter soils and has a lower risk of P export.In these catchments, SimplyP was used to simulate streamflow, sediment, and phosphorus (PP, TRP, TP) over the period of 2010 – 2019. The model is calibrated and validated independently three times to different objective functions (NSE, KGE, NSE log) to provide models focused on peak flows, balanced, and low flows, respectively. Model performance is evaluated over the entire calibration and validation period, as well as year-by-year assessments, which highlights the influence of meteorological and antecedent moisture conditions on model behaviour.