bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the Magnetospheric Plasma Interaction and Solar Illumination on Ion Sputtering of Europa's Surface Ice
Authors: Addison Peter , Liuzzo Lucas , Simon Sven
Published: March 2022

For the entire ion energy range observed at Europa, we calculate spatially-resolved maps of the surface sputtering rates of H2O, O2, and H2 from impacts by magnetospheric ions. We use the perturbed electromagnetic fields from a hybrid model of Europa’s plasma interaction, along with a particle-tracing tool, to calculate the trajectories of magnetospheric ions impinging onto the surface and their resultant sputtering yields. We examine how the distribution of the sputtering rates depends on the electromagnetic field perturbations, the angle between the solar radiation and the corotating plasma flow, and the thickness of the oxygen-bearing layer within Europa's surface. Our major findings are: (a) Magnetic field-line draping partially diverts the impinging ions around Europa, reducing the sputtering rates on the upstream hemisphere, but allowing for substantial sputtering from the downstream hemisphere. In contrast, zero sputtering occurs in much of the downstream hemisphere with uniform electromagnetic fields. (b) If the oxygen-bearing surface layer is thin compared to the penetration depth of magnetospheric ions, thermal ions dominate the O2 sputtering rates, and the region of strongest sputtering is persistently located near the upstream apex. However, if the oxygen-bearing layer is thick compared to the penetration depth, energetic ions sputter the most O2, and the location of maximum sputtering follows the sub-solar point as Europa orbits Jupiter. (c) The global production rate of O2 from Europa’s surface varies by a factor of three depending upon the moon's orbital position, with the maximum particle release occurring when Europa's sun-lit and upstream hemispheres coincide.
Structural analysis of the alpine orogeny in the western High Atlas, Morocco: New insights through a multiscale approach 
Authors: Amarir Salih , Belfoul Mhamed Alaeddine , Amrouch Khalid , Attegue Yousef , Skikra Hamza
Published: March 2022

The Moroccan Atlas is an intracontinental chain resulted from an aborted rifting during the Mesozoic time, by an uplifting and moderate shortening during the Late Cretaceous-Cenozoic period. Several studies have highlighted the role of tectonic inversion in the evolution of the High Atlas Range, where strike-slip faults are commonly been considered as a main component of the alpine signature within the High Atlas belt. However, more recent works have focused on the geodynamic model of the evolution of the Atlas Range using different approaches. The structural history and chronology of events are still matter of debates. To contribute to the later, a combined meso and microstructural study was conducted in the western part of the chain. It provided an attempt to quantify paleo-stresses from structural analysis of the Permo-Triassic extensional phase to the tectonic reversal phases, acting from Cenozoic to present days.
This work highlighted two major tectonic phases: (1) the first represented by an extensive regime, with a sub-horizontal minimal stress σ3 oriented NE-SW and linked to the Central Atlantic occurrence. This stage is characterized by pull apart basins genesis in horst and graben morphology. (2) the second phase represented by a weakly tilted compression with a maximum stress σ1 oriented in set NNE-SSW to NNW-SSE. This compression began in the Tertiary, contemporary with the Africa and Europe collision. the related inversions are printed at the paleozoic basement/mesozoic cover interface from the Eastern area to the Jurassic-Cretaceous and Cenozoic plateaus in the West, passing through the Triassic detrital formations of the Argana corridor.
Keywords: Paleo-stress, Structural analysis, Tectonic inversion, Western high Atlas, Morocco, Alpine orogeny.
Causes of jets in the quasi-perpendicular magnetosheath
Authors: Kajdic Primoz , Raptis Savvas , Blanco-Cano Xóchitl , Karlsson Tomas
Published: March 2022

Magnetosheath jets are currently an important topic in the field of magnetosheath physics. It is thought that 97 % of the jets are produced by the shock rippling at quasi-parallel shocks. Recently, large statistical studies of magnetosheath jets have been performed, however it is not clear whether rippling also produces jets found downstream of quasi-perpendicular shocks. We analyze four types of events in the quasi-perpendicular magnetosheath with signatures characteristic of magnetosheath jets, namely increased density and/or dynamic pressure, that were not produced by the shock rippling: 1) magnetic flux tubes connected to the quasi-parallel bow-shock, 2) non-reconnecting current sheets, 3) reconnection exhausts and 4) mirror mode waves. The flux tubes are downstream equivalents of the upstream traveling foreshocks. Magnetosheath jets can impact the magnetopause, so knowing the conditions under which they form may enable us to understand their signatures in the magnetosphere.
Evaluating Interventions to Improve the Resilience of Transport Networks against Climate-Induced Hazards: A Simulation Approach 
Authors: Nasrazadani Hossein , Adey Bryan
Published: March 2022

Infrastructure systems are susceptible to hazard events, which disrupt their functionality leading to direct and indirect consequences for the users and the owners. To ensure these consequences are not excessive, infrastructure managers have to plan and execute interventions to improve the resilience of their networks. Interventions can contribute to enhancing resilience through a multitude of techniques such as reducing hazard intensity, reducing exposure to hazards, decreasing the vulnerability of exposed assets, implementing adaptive capacity, enhancing restoration programs, and the combination thereof. Moreover, interventions can be executed on a spatially and temporally variant domain, including those that can be executed prior to the occurrence of hazard events, e.g., construction of flood levees; while the hazard is taking place and evolving, e.g., deployment of temporary sandbags during a flood; and after the hazard event, e.g., repair activities. This spatiotemporal variability, along with the possibility of having a portfolio of interventions each targeting certain aspects of resilience, however, has not yet been adequately addressed in the literature. Most studies focused on standalone pre-hazard interventions, and have not addressed the collective benefit of interventions of different types. This study addresses this limitation by proposing a simulation approach to quantitatively evaluate the effects of portfolios of interventions of various types for improving the resilience of transport networks against climate-related hazards. It is achieved through a resilience assessment methodology that, under both existing and intervened conditions, exhaustively models the: 1) occurrence and evolution of hazards, 2) performance of transport network over the course of hazard evolution, and 3) restoration efforts to recover performance. Subsequently, through generating a host of simulated scenarios, interventions are evaluated based on their contribution to reducing the ensuing economic consequences, e.g., repair costs, as well as socio-economic ones, e.g., increased travel time and loss of connectivity. This approach will be showcased through an application to a transport network located in Switzerland subject to heavy rainfall, flooding, and landslides. The proposed simulation approach serves as a virtual representation of the real system that can enable decision-makers to objectively investigate and compare the effects of various interventions.
Experimental CO2-driven granular flows under Martian atmospheric conditions 
Authors: Roelofs Lonneke , Conway Susan , Sylvest Matthew , Patel Manish , McElwaine Jim , Kleinhans Maarten , de Haas Tjalling
Published: March 2022

Martian gullies are alcove-channel-fan systems that have been hypothesized to be formed by the action of liquid water and brines, the effects of sublimating CO2 ice, or a combination of these processes. Recent activity and new flow deposits in these systems have shifted the leading hypothesis from water-based flows to CO2-driven flows, as it is hard to reconcile present activity with the low availability of atmospheric water under present Martian conditions. Direct observations of flows driven by metastable CO2 on the surface of Mars are however nonexistent, and our knowledge of CO2-driven flows under Martian conditions remains limited. For the first time, we produced CO2-driven granular flows in a small-scale flume under Martian atmospheric conditions in the Mars Chamber at the Open University (UK). The experiments were used to quantify the slope threshold and CO2 fraction limits for fluidization. With these experiments, we show that the sublimation of CO2 can fluidize sediment and sustain granular flows under Martian atmospheric conditions, and even transport sediment with grain sizes equal to half the flow depth. The morphology of the deposits is lobate and depends highly on the CO2-sediment ratio, sediment grain size, and flume angle. The gas-driven granular flows are sustained under low (<20º) flume angles and small volumes of CO2 (around 5% of the entire flow). Pilot experiments with sediment flowing over a layer of CO2 suggest that even smaller percentages of CO2 ice are needed for fluidization. The data further shows that the flow dynamics are complex with surging behavior and complex pressure distribution in the flow, through time and space.
Iron rich glauconite sand as an efficient phosphate immobilising agent in river sediments
Authors: Xia Lei , Verbeeck Mieke , Bruneel Yaana , Smolders Erik
Published: March 2022

The reductive dissolution of iron (Fe) (oxy)hydroxides in sediments releases phosphorus (P) to the overlying water and may lead to eutrophication. Glauconite sands (GS) are rich in Fe and may be used as readily available P sorbents. This study was set up to test effects of dose and type of GS on the P immobilisation in sediments under hypoxic conditions. Three different GS were amended to a P-rich river sediment at doses of 0% (control), 5% and 10% (weight fractions) and incubated with overlying water in batch laboratory conditions. Glutamate was added to the solution after 15 days to deplete any residual dissolved oxygen from the sediment-water interface. In the first 15 days, the P concentration in the overlying water peaked to 1.5 mg P L-1 at day 9 in the control and decreased to 0.9 mg P L-1 at lowest Fe-dose and to 0.03 mg P L-1 at the highest Fe-dose, the effects of GS type and dose were explained by the Fe dose. After 15 days, the added glutamate induced a second, and larger peak of P in the overlying water in sediment, that peak was lower in amended sediments but no GS dose or type related effects were found. This suggests that freshly precipitated P species at the sediment-water interface can be remobilised. This study highlights the potential for using this natural mineral as a cheap and easily available sediment remediation material, but its longevity under rare extreme conditions needs to be further investigated.
Patch- to hillslope-scale geodiversity: Implications for durability of dryland ecosystems under climatic changes
Authors: Stavi Ilan , Argaman Eli , Basson Uri , Yizhaq Hezi
Published: March 2022

Geodiversity encompasses the natural heterogeneity of geologic, topographic, and pedogenic systems. It determines biodiversity and dictates a range of ecosystem services. Specifically, since geodiversity regulates hydrological connectivity and soil properties, it affects the soil-water dynamics. This feature is particularly relevant for drylands, where primary productivity is predominantly determined by soil-water availability. We present results and insights obtained in a set of recent and ongoing studies in shrublands of the semi-arid Negev region of southern Israel, revealing that hillslope-scale geodiversity dictates the vitality of shrubs. The region has experienced consecutive droughts and a substantial precipitation decrease over the past two decades. In high-geodiversity hillslopes – defined with a thin (~ 0.1 m thickness) and stony calcic xerosol layer that lies on highly-weathered calcareous bedrocks – shrubs are abundant, with high species richness and high vitality. At the same time, in low-geodiversity hillslopes, defined with a thick soil layer (> 1 m thickness) and no stoniness, shrubs are very sparse and dominated by one species (Noaea mucronata (Forssk.) Asch. & Schweinf.), of which the majority have not survived the recent prolonged droughts. These studies show that hillslope-scale geodiversity alleviates the water stress imposed on the shrubs, improving their durability under long-term droughts and climate change.

A complementary study that is currently being implemented along an aridity gradient (semi-arid, arid, and hyper-arid regions) in southern Israel reveals the substantial impact livestock trampling routes (also known as treading paths, livestock terracettes, cattle trails, migration tracks, cowtours, etc.) have on patch-scale geodiversity, consequently affecting geo-ecosystem functioning. Specifically, the extremely compacted routes minimize rainwater infiltration, thus increasing runoff-rainfall ratio. The generated runoff flows downslope, where it accumulates in shrubby patches. Thus, the shrubs experience higher soil-water availability, and are more resilient to drought episodes and climatic changes. The effect of the trampling routes is further amplified by accentuating the hillslopes’ characteristic ‘step-like profile’, which reduces hydrological connectivity at the hillslope scale, thus minimizes runoff leakage from the system. 

Note: the study is funded by the Israel Science Foundation (ISF), grant number 602/21.
Monitoring Global Radiative Forcing from Space
Authors: Soden Brian , Kramer Ryan , He Haozhe
Published: March 2022

Changes in atmospheric composition, such as increasing greenhouse gases, cause an initial radiative imbalance to the climate system, quantified as the instantaneous radiative forcing. This fundamental metric has not been directly observed globally and previous estimates have come from models. In part, this is because current space-based instruments cannot distinguish the instantaneous radiative forcing from the climate’s radiative response. We apply radiative kernels to satellite observations to disentangle these components and find all-sky instantaneous radiative forcing has increased 0.53 ± 0.11 W/m2 from 2003 to 2018, accounting for positive trends in the total planetary radiative imbalance. This increase has been due to a combination of rising concentrations of well-mixed greenhouse gases and recent reductions in aerosol emissions. These results highlight distinct fingerprints of anthropogenic activity in Earth’s changing energy budget, which we find observations can detect within 4 years.
Exploring lava dome mechanics & structure: how does stability change as a function of rock strength?
Authors: Harnett Claire , Heap Michael
Published: March 2022

Lava dome collapse hazards are intimately linked with their morphology and internal structure. We present new lava dome emplacement models that use calibrated rock strengths and allow material behaviour to be simulated for three distinct units: (1) a ductile, fluid core; (2) a solid upper carapace; and (3) disaggregated talus slopes. We first show that relative proportions of solid and disaggregated rock depend on rock strength, and that disaggregated talus piles can act as an unstable substrate and cause collapse, even in domes with a high rock strength. We then simulate sequential dome emplacement, demonstrating that renewed growth can destabilise otherwise stable pre-existing domes. This destabilisation is exacerbated if the pre-existing dome has been weakened following emplacement, e.g., through processes of hydrothermal alteration. Finally, we simulate dome growth within a crater and show how weakening of crater walls can engender sector collapse. A better understanding of dome growth and collapse is an important component of hazard mitigation at dome-forming volcanoes worldwide.
Current and future risks of unprecedented UK droughts
Authors: Chan Wilson , Shepherd Theodore , Facer-Childs Katie , Darch Geoff , Arnell Nigel , van der Wiel Karin
Published: March 2022

The UK has experienced recurring periods of hydrological droughts in the past and their frequency and severity are predicted to increase with climate change. However, quantifying the risks of extreme droughts is challenging given the short observational record, the multivariate nature of droughts and large internal variability of the climate system. We use EC-Earth time-slice large ensembles, which consist of 2000 years of data each for present day, 2°C and 3°C conditions, to drive the GR6J hydrological model at UK river catchments to obtain a large set of plausible droughts. Applying the UNSEEN (UNprecedented Simulation of Extreme Events using ENsembles) approach show an increasing chance of unprecedented dry summers with future warming and highlight the chance of an unprecedented drought with characteristics exceeding that of past severe droughts.

This study also aims to bridge the probabilistic UNSEEN approach with “bottom-up” storyline approaches. Physical climate storylines of preconditioned compound drought events are created by searching within the large ensemble for events resembling specific conditions that have led to past severe droughts and are relevant for water resources planning. This includes conditions such as 1) dry autumns followed by dry winters, 2) consecutive dry winters (both of which are relevant for slow-responding catchments), and 3) dry springs followed by dry summers (relevant for fast-responding catchments). The storylines can be used to understand the conditions leading to unprecedented droughts and the impacts of future droughts triggered by the same conditions. Unprecedented drought sequences and synthetic experiments conditioned on these storylines can be used to stress-test hydrological systems and inform decision-making.
Quantifying the contribution of an individual to making extreme weather events more likely
Authors: Lott Fraser , Ciavarella Andrew , Kennedy John , King Andrew , Stott Peter , Tett Simon , Wang Dongqian
Published: March 2022

Probabilistic event attribution aims to quantify the role of anthropogenic climate change in altering the intensity or probability of extreme climate and weather events. It was originally conceived to calculate the costs associated with any increased likelihood of the meteorological event in question. However, only recently have such studies attempted to divide liability between polluting nations and ascribe a cost. Recent protests indicate a perception that older generations have the greater responsibility for climate change. In this paper, we examine how a portion of the cost of an event can be attributed to any individual person, according to their age and nationality. We demonstrate that this is quantitatively feasible using the example of the 2018 summer heatwave in eastern China and its impact on aquaculture. A relatively simple technique finds sample individuals responsible for between 0.53 and 18.10 yuan, increasing with their age and their country’s emissions over their adult lifetime since the first international consensus on carbon emissions was reached. This provides an illustration of the scale of such responsibilities, and how it is affected by national development and demographics. Such data can support decisions, at national and international levels, on how to fund recovery from climate impacts. It offers a simple quantitative approach for individuals to know their impact on the climate, or for governments to use in making policy decisions about how best to distribute costs of climate change.
A non-destructive approach to estimate buttress volume using 3D point cloud data
Authors: Han Tao , Bax Connor , Wagers Steven , Sánchez‐Azofeifa Arturo
Published: March 2022

Buttressed trees have one of the largest sources of variation in volume or biomass estimates in tropical forests. Buttresses provide mechanical support for trees and offer other essential ecological functions such as nutrient acquisition. Here, we use an Alpha Shape Algorithm (ASA) based on a 3D point cloud to estimate the volume of 30 buttressed trees collected using Terrestrial Photogrammetry (TP). We also calculated the buttresses volume using allometric models developed using the Diameter Above the Buttress (DAB) and the Diameter computed from non-convex (Darea130) and convex area (Dconvex130) at breast height (1.3 m). To demonstrate the broader generalization of our allometric models, we validated the developed models using independent data obtained by Terrestrial Laser Scanning (TLS) and destructive measurement. Volume estimated by the ASA showed a high agreement with the reference volume acquired by the Smalian formula (RRMSE of 0.08 and R2 = 0.99 regardless of species effect). Our results suggest that the DAB seems to be the most advanced predictor for volume, with the lowest Akaike information criterion (AIC) of -62.4 than the Darea130 (49.2)and the Dconvex130 (30.3). At the same time, the DAB (RRMSE of 0.2) and Darea130 (RRMSE of 0.2) show similar performance when validated with independent data sets. Our results indicate that the ASA is more reliable and efficient than allometric models for buttress modelling. Our results also provide a solid foundation for buttress modelling, as we use more buttressed trees (45) for allometric model development than previous studies. Furthermore, the proposed non-destructive method can help to correct the bias in present and past estimates of volume and biomass of large trees, which are keystone components to understanding biomass allocation and dynamics in tropical forests.
Response of a small river plume on wind forcing
Authors: Osadchiev Alexander , Sedakov Roman , Barymova Alexandra
Published: March 2022

Wind forcing is the main driver of river plume dynamics. Direction and magnitude of wind determine position, shape, and size of a river plume. The response of river plumes on wind forcing was simulated in many numerical modeling studies; however, in situ measurements of this process are still very scarce. In this study, we report the first direct measurements of frontal movement of a small river plume under variable wind forcing conditions. Using quadcopters, we performed nearly continuous daytime aerial observations of the Bzyb river plume located in the non-tidal Black Sea. The aerial remote sensing was accompanied by synchronous in situ measurements of wind forcing. We assessed spreading patterns of the plume and evaluated movement velocity of its outer border with unprecedentedly high spatial (~ 10 m) and temporal (~ 1 minute) resolution, which was not available in previous studies based on in situ measurements and satellite observations. Based on the collected data, we evaluated the time of response of plume spreading dynamics on changes in wind forcing conditions. The advection velocity of the outer plume border shows linear relation to wind speed with very small response time (10-20 minutes). The reversal between upstream/downstream plume spreading occurs during several hours under moderate wind forcing conditions. These reversals involve only near-field part of the plume, which cause detachment of the far-field part of the plume. The obtained results are crucial for understanding and simulating spreading dynamics of small river plumes worldwide.
Quantifying how small-scale, short-lived, advective and biologically driven processes alter the carbon uptake capacity in a shelf sea
Authors: Macovei Vlad , Callies Ulrich , Calil Paulo , Voynova Yoana
Published: March 2022

Marine uptake of carbon dioxide limits the atmospheric concentration growth. Continental shelf seas are important areas for this uptake, but are also highly variable environments, with indications that their sink capacity is weakening. A way to reduce uncertainty of budgeting is to increase our observational capacity, such as through FerryBox installations on Ships-of-Opportunity. Here, we compare FerryBox observations in the North Sea for periods of interest in the autumn seasons of 2019 and 2020. We show that short-lived and small to medium-scale events can be identified when the sampling resolution is adequately high, and that these events cause changes in some essential environmental variables on the same magnitude as seasonal cycles. In particular, these events rapidly lowered seawater pCO2 by 8-10%. In September 2019, an advectively-driven event caused a previously carbon source area (flux of 1.3 ± 0.6 mmol m-2 day-1) to be in relative balance with the atmosphere (new flux of −0.04 ± 0.34 mmol m-2 day-1). In November 2020, a late autumn bloom caused another previously carbon source area (flux of 2.7 ± 2.1 mmol m-2 day-1) to potentially become a carbon sink (flux of −0.6 ± 1.4 mmol m-2 day-1 during the bloom). We demonstrate the importance of including such events in regional carbon budget assessments and advocate for the tuning of models in order to capture this small-scale variability.
Estimation of the solar wind extreme events.
Authors: Larrodera Carlos , Nikitina Lidia , Cid Consuelo
Published: March 2022

This research provides an analysis of extreme events in the solar wind and in the magnetosphere due to disturbances of the solar wind. Extreme value theory has been applied to a 20-year data set from the Advanced Composition Explorer spacecraft for the period 1998–2017. The solar proton speed, solar proton temperature, solar proton density, and magnetic field have been analyzed to characterize extreme events in the solar wind. The solar wind electric field, vBz has been analyzed to characterize the impact from extreme disturbances in the solar wind to the magnetosphere. These extreme values were estimated for 1-in-40- and 1-in-80-year events, which represent two and four times the range of the original data set. The estimated values were verified in comparison with measured values of extreme events recorded in previous years. Finally, our research also suggests the presence of an upper boundary in the magnitudes under study.
Large interannual variability in supraglacial lakes around East Antarctica
Authors: Arthur Jennifer , Stokes Chris , Jamieson Stewart , Carr Rachel , Leeson Amber , verjans Vincent
Published: March 2022

Antarctic supraglacial lakes (SGLs) have been linked to ice shelf collapse and the subsequent acceleration of inland ice flow. These processes are difficult to capture in numerical ice sheet models, but those that include them project higher sea-level contributions from Antarctica. However, observations of SGLs in Antarctica remain relatively scarce and their seasonal variability is largely unknown, making it difficult to assess whether some ice shelves are close to thresholds of stability under climate warming. Here, we quantify the variability in SGL distributions and volumes across the entire East Antarctic Ice Sheet around the peak of seven consecutive melt seasons (2014-2020). We investigate potential climatic controls on SGL development and near-surface (i.e. firn) conditions generated by ERA5 climate reanalysis and the Community Firn Model forced by the regional climate model MARv3.11. Interannual variability in SGL volume is >200% on some ice shelves, but patterns are highly asynchronous. More extensive, deeper SGLs correlate with higher summer (December-January-February) air temperatures, but comparisons with modelled melt and runoff are complex. However, we find that modelled January melt and the ratio of November firn air content to summer melt are important predictors of SGL volume on some potentially vulnerable ice shelves, suggesting large increases in SGLs should be expected under future atmospheric warming. 
Geophysical and structural characterisation of a granodioritic MD-BTES test-site
Authors: Bossennec Claire , Seib Lukas , Frey Matthis , Burschil Thomas , Buness Anton Hermann , Welsch Bastian , Sass Ingo
Published: March 2022

Geothermal energy and thermal energy storage are essential components in balancing a decarbonated future energy supply. The north-eastern shoulder of the Upper Rhine Graben (URG), with its Variscan basement belonging to the Mid-German Crystalline High, is a potential target area for heat storage projects. Ganodioritic units in the city area of Darmstadt provide suitable thermo-mechanical properties to implement a Medium Deep Borehole heat exchanger Thermal Energy Storage (MD-BTES). This study focuses on the structural architecture of such crystalline units, representing a heterogeneous fracture and fault network. An approach combining geophysical characterisation and the analysis of surface fracture network analogue is performed to quantify the dimensions and topology of such a fracture network in the subsurface.

Two 2D seismic profiles helped to characterise the deep subsurface structures of the BTES demo site area and to localise the boundaries between the unweathered basement, the weathered basement, and the overlying sedimentary layers. The weathered basement and Permian volcano-sedimentary and Quaternary fluviatile units build the near-surface groundwater aquifer. This shallow aquifer requires a detailed investigation, performed through electrical resistivity mapping, near-surface S-wave refraction seismic survey, ground-penetrating radar lines and radon emanations profiles, combined with shallow geotechnical drillings. Selected surface analogues are located in the northern Odenwald Massif, the most extensive outcropping section of the Mid-German Crystalline High. The first analogue is a pit located 150 m apart from the BTES demo site. The second is the Mainzer Berg quarry in the Sprendlinger Horst, at a 12 km westbound distance, which belongs to Variscan granodioritic and granitic units with similar properties. Derived from these analogues, the fracture length distribution follows the power-law with an exponent about -2. The main relevant orientations identified are trending N030°E -N040°E, N090°E -N100°E, N120°E -N130°E and N165°E, with an overall fracture density of 3.06 frac.m-1 for the demo site subsurface. Additionally, the connectivity of the fracture network is heterogeneous due to clustering. Such clustering also affects weathered horizons, which constitute the near-surface groundwater aquifer.

These fracture network properties are then implemented into sub-surface semi-artificial discrete fracture network (DFN) models to quantify at the first-order the flow properties of such heat storage rocks. This approach allows a successful characterisation of the BTES site, improves the local reservoir model accuracy and ensures an optimal assessment of the storage system behaviour.
MIdAS---MultI-scale bias AdjuStment
Authors: Berg Peter , Bosshard Thomas , Yang Wei , Zimmermann Klaus
Published: March 2022

Bias adjustment is the practice of statistically transforming climate model data in order to reduce systematic deviations from a reference data set, typically some sort of observations. There are numerous proposed methodologies to perform the adjustments -- ranging from simple scaling approaches to advanced multi-variate distribution based mapping. In practice, the actual bias adjustment method is a small step in the application, and most of the processing handles reading, writing and linking different data sets. These practical processing steps become especially heavy with increasing model domain size and resolution in both time and space. Here, we present a new implementation platform for bias adjustment, which we call MIdAS (MultI-scale bias AdjuStment). MIdAS is a modern code implementation that supports features such as: modern Python libraries that are suitable for large computing clusters, state-of-the-art bias adjustment methods based on quantile mapping, "day-of-year" based adjustments to avoid artificial discontinuities, and also introduces cascade adjustment in time and space. The MIdAS platform has been set up such that it will support development of methods aimed at higher resolution climate model data, explicitly targeting cases where there is a scale mismatch between data sets. In this presentaton, we describe the MIdAS assumptions and features, and present results from the main evaluation of the method for different regions around the world. We also present the most recent development of MIdAS towards different parameters.
Using citizen science to digitise 3 million hand-written tide-gauge data entries
Authors: Williams Joanne , Matthews Andrew , Bradshaw Elizabeth
Published: March 2022

How can you get sea-level data faster than one day at a time? Get it from the past!

 

The port of Liverpool is one of the world's longest sea-level records, but for the 1800s the only digital record is hand-calculated monthly mean data, which have many gaps. Hand-written ledgers contain high frequency (15 minute) records from 1853 to 1903, both at Liverpool and neighbouring Hilbre Island. In 2021, we coordinated over 3600 volunteers through the Zooniverse website to transcribe this data. At the time of writing this abstract, the transcription is nearing completion.  From the newly digitised data we can examine whether tides in the Mersey have changed and reassess the frequency of rare storm surge events. We now understand the reason for the gaps in the Liverpool monthly mean sea-level, which are due to a dock fire and an intermittent siltation problem at low water, and may be able to use the Hilbre data to help fill them.

 

We report on the feasibility of this process for other transcription projects, the unusual quality control requirements for volunteer transcription, and present the newly restored data with 19th Century tides, storm surges and sea-level.

 
Insights on factors controlling rockslope failure from pre-event cracking
Authors: Lagarde Sophie ,  Dietze Michael , Hammer Conny , Zeckra Martin , Voigtländer Anne , Illien Luc , Schöpa Anne , Hirschberg Jacob , Hovius Niels , Turowski Jens M.
Published: March 2022

In order to reduce the societal impact of mass-wasting events, we need observations to investigate the factors that control slope failure, such as the state of crack propagation along a failure plane. However, usually the failure plane is not accessible in-situ. Hence, cracks have to be monitored indirectly, for example using seismic methods.

We analysed the data from a seismometer array in the Illgraben catchment, Switzerland, that had registered a series of crack propagation and mass-wasting events, leading to a main event that happened on 2 January 2013. We used a state-of-the-art machine learning technique based on hidden Markov models to detect and classify the seismic signals of crack events. We obtained the temporal evolution of three signal types: (1) single crack signal, (2) rock avalanche and (3) rockfall activity due to debris remobilization. The temporal evolution of the number of cracks showed a linear trend in the weeks prior to the main mass-wasting event and, in the hours preceding the main event, a sigmoidal exponential growth. Using these observations, we propose a mechanistic model to describe the rupture of the failure plane. The model considers the internal parameter of the total crack boundary length as the primary control on failure plane evolution, in addition to the previously suggested crack propagation velocity control parameter. According to this model, internal parameters appear to be the dominant control for the failure plane growth at a slope scale.

 
Adiabatic, Constrained, Stochastic Eddy Parameterisation
Authors: Wilson Chris , Hughes Chris W. , Williams Simon D. P. , Blaker Adam T.
Published: March 2022

Mesoscale eddy-permitting ocean models will be needed as a component of climate ensemble projections most likely for the next decade or more.   However, the kinetic energy and other measures of variability are typically an order of magnitude too weak at this nominal 0.25 degree lon-lat resolution.    This is predominantly due to excessive gridscale damping of momentum, needed for computational stability, which is believed to kill a large fraction of the energy source of the kinetic energy inverse cascade.   The KE inverse cascade is associated with the generation of intrinsic chaotic variability and ensemble spread, hence the estimation of potential predictability, but also with slower, larger-scale variability associated with climate.  The familiar Gent and McWilliams (1990) eddy parameterisation is problematic when applied to eddy-permitting models, where eddies are partially resolved, and it also tends to damp variability rather than energise it.   In response to this problem, several recent studies have focussed on the KE backscatter problem, which each attempt to increase the upscale transfer of KE, either deterministically or stochastically.

Stochastic parameterisation of sub-gridscale eddies has recently become a popular approach in ocean modelling, having been used in atmospheric modelling for many years, but there is still a diverse range of approaches for constraining either the underlying physics (how the forcing is applied) or the statistics (the spatiotemporal signature of the forcing).   This study explores some basic recipes for constructing the stochastic model from statistics of either observations or higher-resolution models.  The stochastic forcing, representing the sub-gridscale effects of eddies in our eddy-permitting simulations, is also applied adiabatically – to mimic the predominant behaviour of mesoscale eddies in the ocean interior and to preserve large-scale watermasses.   A theoretical challenge, which we explore, is to connect the applied, weakly imbalanced forcing, to a response in kinetic energy and upscale transfer.  This must also be applied without generating numerical instability.  
Can ground infrasound measurements be a useful complementary technology in studies of streamer events?
Authors: Sindelarova Tereza , Kozubek Michal , Podolska Katerina , Bondar Istvan , Pasztor Marcell , Kuchelbacher Lisa
Published: March 2022

Streamer events are induced by breaking of planetary waves near the tropopause. Streamers are significant transient disturbances to the seasonal circulation patterns in the tropopause-stratosphere region at mid latitudes. They modify dynamics of the polar jet stream and of the lower stratosphere.  At streamers’ flanks, strong wind shear occurs and gravity waves can be excited.  Western Europe and the surrounding regions of the North Atlantic are typical regions where streamer events develop.

Long range infrasound propagation is mainly controlled by temperature and wind fields in the atmosphere. Zonal winds in the stratosphere and jet stream near the tropopause belong to key factors that drive infrasound propagation.

A feasibility study on utilisation of ground infrasound measurements in research of streamer events was performed under the ESA’s Aeolus+Inovation project Lidar Measurements to Identify Streamers and Analyse Atmospheric Waves. Three western stations of the Central and Eastern European Infrasound Network WBCI (50.25°N 12.44°E), PVCI (50.53°N 14.57°E), and PSZI (47.92°N 19.89°E) were included in the study of streamer events from February 2020 to March 2021. WBCI is a large aperture array used for observations of low frequency infrasound in the frequency range of 0.0033-0.4 Hz. The stations PVCI and PSZI operate in the infrasound band of 0.05-5 Hz. We focused on statistical comparison of infrasound arrival parameters in periods influenced by streamer events and on calm days.

The presented analysis of the data of the three infrasound stations located in Central Europe did not identify significant first order phenomena related to streamer events. Considering further streamer events and including more stations is necessary to find out if ground infrasound observations could serve for monitoring of streamer events.

 
Increasing the episodic glacial lake outburst flood hazard in response to surge glaciers in the Karakoram
Authors: Bazai Nazir , Cui Peng , Carling Paul , Wang Hao , Hassan Javed
Published: March 2022

In contrast to glaciers in other areas of the world, the Karakoram glaciers appear to be stable or increasing mass in response to global climate change, a phenomenon known as the 'Karakoram anomaly.' Many glaciers are experiencing irregular, frequent, and rapid frontal advances (surges), which cause natural hazards by obstructing river channels forming ice-dammed lakes, consequent outburst floods and posing threats downstream over the region. Predicting the phenomenon to protect downstream communities remains challenging around the globe. The determination of the surge characteristics, timing and evolution of lakes and GLOFs is fundamental to flood control and disaster management. This study documents 179 glacial lake outburst floods (GLOFs) that occurred from 1533 to 2020 in five major valleys. Sixty-four of the events took place after 1970, and 37 of these had remote sensing imagery that covered the GLOF formation to breaching sequence. Thirty-six glaciers were associated with GLOFS due to ice-front advance building ice barriers in rivers. The Kayger and Khurdopin glaciers are the most hazardous examples, responsible for 31.8% of major GLOFs in the Karakoram. Using a cross-correlation feature-tracking technique on remote sensing imagery, we analyzed ten surge glaciers and documented six surge events from 1990 to 2019. Results show periodic surge cycles for the Khurdopin, Kyager, Shishper, and Chilinji glaciers of c. 15–20 years, with a surge velocity in the mid-2010s higher than that of the late 1990s for all studied glaciers. The higher velocity of a glacier increases the risk of flooding downstream of the terminus because the transfer of a huge ice mass towards the terminus during the surge is a key factor for conduit development, formation and reformation of a series of ice-dammed lakes, thus determining the magnitude and frequency of outburst flood events. The response of Karakorum glaciers to global warming and climate forcing, comprising a continuum of glacier mass gain, ice thinning, and ice advance has resulted in lake formation and ice dam failures. We predict the frequency of GLOFs will increase in the future. These findings support the increasing anomalous behavior of glaciers in the Karakoram region. A conceptual model of ice-dammed lake formation and GLOF initiation in response to glacier surging is presented to synthesize the detailed observations.
Climate change effects in a Mediterranean island and streamflow changes for a small area using EURO-CORDEX simulations combined with the SWAT model
Authors: Marras Pier Andrea , Lima Daniela C.A. , Soares Pedro M.M. , Cardoso Rita M. , Daniela Medas , Elisabetta Dore , Giovanni De Giudici
Published: March 2022

Climate change effects on the hydrologic cycle are a main concern for the evaluation of water management strategies. Climate models project important precipitation changes for the future, considering greenhouse emission scenarios. In this study, the EURO-CORDEX (European COordinated Regional Downscaling Experiment) climate models were first evaluated in a Mediterranean island (Sardinia), against observed precipitation for a historical reference period (1976-2005). A weighted Multi-Model Ensemble (ENS) was built, weighting the individual models based on their ability to reproduce observed rainfall. Future projections (2071-2100) were carried out, following the RCP-8.5 emissions scenario, to evaluate future changes in precipitations. ENS was then used as climate forcing for the SWAT model (Soil and Water Assessment Tool), with the aim to assess the consequences of such projected changes on streamflow and runoff of two small catchments located in the South-West Sardinia. Results showed that a decrease of mean rainfall values, up to -25 % at yearly scale, is expected for the future, along with an increase of extreme precipitation events. Particularly, in the eastern and southern areas, extreme events are projected to increase by 30%. Such changes reflect on the hydrologic cycle with a decrease of mean streamflow (-18% to -25%) and runoff (-12% to -18%), except in spring, when runoff is projected to increase by 20-30%. These results stress that Mediterranean is a hotspot for the climate change and the use of model tools can provide useful information to adopt water and land management strategies to deal with such changes.
Soil greenhouse gas fluxes following tropical deforestation for fertilizer-intensive sugarcane cultivation in northwestern Uganda
Authors: Tamale Joseph , van Straaten Oliver , Hüppi Roman , Turyagyenda Laban Frank , Fiener Peter , Doetterl Sebastian
Published: March 2022

Deforestation followed by fertilizer intensive agriculture is widely recognized as a significant contributor to anthropogenic greenhouse gas emissions (GHG), particularly carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). However, empirical studies focusing on soil GHG flux dynamics from deforestation hotspots in the tropics are still limited creating major uncertainties for constraining global GHG budgets. In this study, we investigated how deforestation for fertilizer intensive sugarcane cultivation in Uganda affects soil-borne GHGs. Therefore, soil GHG fluxes were measured in a primary forest and in a completely randomized experiment premised in the neighboring sugarcane fields with different fertilizer regimes, representing both smallholder and industrial-scale sugarcane farm management. Despite the use of different fertilization rates (low, standard, and high) as treatments for the sugarcane CRD experiment, neither auxiliary controls nor soil GHG fluxes significantly differed among the CRD treatments. Soil respiration was higher in the sugarcane than in the forest, which we attribute to the increased autotrophic respiration from the sugarcane’s fine root biomass and the likely exposure of the sugarcane’s larger soil organic carbon stocks to microbial decomposition through ploughing operations. The forest soils were a stronger net sink of CH4 than the sugarcane soils despite forest soils having both higher bulk densities and larger water-filled pore space (WFPS), and we suspect that this was due to alteration of the methanotroph abundance upon the conversion. Soil N2O emissions were smaller in the sugarcane than in the forest, which was surprising, but most likely resulted from the excess N being lost either through leaching or uptake by the sugarcane crop. Only seasonal variability in WFPS, among the auxiliary controls, affected CH4 uptake at both sites and soil CO2 effluxes in the sugarcane. Noteworthy, soil N2O fluxes from both sites were unaltered by the seasonality-mediated changes in auxiliary controls. All the findings put together suggest that forest conversion for sugarcane cultivation alters soil GHG fluxes by increasing soil CO2 emissions and reducing both soil CH4 sink strength and soil N2O emissions.