bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrated knowledge systems towards flood resilience and sustainable solid waste management in South African urban informal settlements
Authors: Johnson Katelyn , Nyamwanza Admire
Published: March 2024

Climate change, an increasing urban population, and poor urban planning have increased flood-risk and the accompanying solid waste challenge in many coastal urban areas in developing countries. These challenges are more pronounced in informal settlements because: (a) they are often built on environmentally fragile locations such as river banks and coastal shores with high exposure to floods, (b) high poverty levels among residents resulting in low adaptive capacity, and (c) marginalisation of these localities emanating from their non-recognition in the larger city framework. Against this background, flood-risk assessments and response initiatives in these areas have primarily been informed by scientific approaches such as geographical information systems, without adequate incorporation of other forms of knowledge. Using the case of the coastal city of Durban, South Africa, our project explores the benefits of combining perspectives from different knowledge systems in understanding flood-risk and the accompanying solid waste challenge in urban informal settlements, towards developing solutions that are based on contextual and experiential aspects. Methodological techniques used include interviews and workshops with key experts and with informal settlement residents, and extensive reviews of literature.  Emerging findings show that holders of scientific, practitioner, and local knowledge vis-à-vis flood risk and waste management are active in the selected case study informal settlement. They have, in isolated cases, collaborated particularly around a) generation and distribution of flood early warnings, b) river clean-up initiatives, and c) catchment rehabilitation projects, with clear benefits for flood resilience and solid waste management. We find that there is need for a clear framework for integrating knowledge systems towards flood resilience and solid waste management in these contexts and the project has developed a draft framework. Integrating knowledge systems will: i) ensure the participation of different actors in mapping flood risk thereby creating a sense of ownership and ensuring uptake of and support for solutions crafted to deal with flood risk and the solid waste challenge; and ii) open up opportunities for coordinated support from various actors for a range of decisions around flood risk response preparation, flood and waste infrastructural design and mitigation of waste-induced flood destruction of infrastructure.
Towards data assimilation in the Probabilistic Tsunami Forecasting digital twin
Authors: Magni Valentina , Volpe Manuela , Cordrie Louise , Bänsch Michel , Løvholt Finn , Lorito Stefano , Romano Fabrizio , Tonini Roberto , Drøsdal Ida , Gibbons Steven , Behrens Jörn
Published: March 2024

Probabilistic Tsunami Forecasting (PTF) uses the initial magnitude and location of a seismic event to forecast the tsunami intensity at coastal locations as a probability distribution (Selva et al., 2021). The PTF workflow can be summarized in the following steps: 1) select the ensemble of scenarios and the probability of a scenario coinciding with the actual earthquake; 2) for each scenario, compute a tsunami intensity measure (e.g., maximum inundation height) at coastal locations of interest – either by running shallow water tsunami propagation models with the code Tsunami-HySEA, or by retrieving it from a precomputed database of scenarios; 3) combine the intensity measure with scenario probabilities to compute hazard curves; 4) convert the probabilities into alert levels according to a predefined rule; and 5) visualise the results. More recently, developments in the context of the eFlows4HPC project have allowed for the possibility of updating the probabilities of the ensemble elements based on new data (focal mechanism and sea level data) to make the forecast more precise and/or reduce the uncertainties. Building on these new developments, we present the first results using an even more general PTF workflow here, implementing dynamically the assimilation of new data, such as new estimates of the earthquake magnitude and location, focal mechanism, GNSS displacements, and sea level data. In particular, new estimates of the source will be used to compute a new ensemble, new probabilities, and will trigger Tsunami-HySEA simulations of the new scenarios in the ensemble. If sea level and/or GNSS data are available, we compute the misfit between the data and the results of the simulations to further update the probabilities and reduce the overall uncertainty in the forecast. We use the 2020 Samos earthquake as a first test of the new workflow that includes data assimilation, but further testing will be done for other events in the Mediterranean Sea and Pacific Ocean. Implementing a continuous update of the results within the above outlined dynamic workflow triggered by the arrival of new data represents a crucial element in transforming the PTF into a digital twin.This work is supported by the European Union’s Horizon Europe Research and Innovation Program under grant agreement No 101058129 (DT-GEO, https://dtgeo.eu/).
CFC stream water mean transit times reveal subsurface flow processes across scales at Krycklan
Authors: Kolbe Tamara , Vergnaud-Ayraud Virginie , Yvard Barbara , Bishop Kevin
Published: March 2024

Catchment transit time distributions span the range from minutes to hours (e.g. overland flow) to years, decades and longer. As time-variant catchment descriptors they are useful indicators for flow and transport processes. Stable water isotopes are established tracers to inform about young water components in stream water, but are less well-suited to defining ages for the older components of the transit time distribution. To infer slow flow water components, tracers that are able to date water over longer timescales are needed.Here, we used atmospheric tracers (i.e. chlorofluorocarbons (CFCs)) that are able to cover the timescale of subsurface flow over decades to determine mean transit times of stream water. CFCs are well established tracers for dating groundwater, but their use is limited in surface waters as they might partially reequilibrate with ambient atmospheric concentrations of CFCs within a few hours. We measured CFCs at different subcatchment outlets of the Krycklan catchment basin under different flow conditions (49 samples in total). Krycklan is a boreal research catchment in northern Sweden at which stable water isotopes are extensively used to understand hydrological processes. The CFC results show that stream water mean transit times vary between 32 years and 59 years. These ages are similar to those observed for groundwater in the aquifer. This, and the patterns for individual CFCs suggest limited reequilibration with contemporary atmospheric CFC concentrations. Mean transit times across scales are independent of catchment size suggesting local groundwater contributions to streams. Furthermore, mean transit times negatively correlate with specific discharge supporting findings of increasing young water components during high flow conditions. 
Vertical Variability in Leaf Traits and Environmental Conditions: Implications for Evapotranspiration and Net Ecosystem Exchange above the Amazon Rainforest
Authors: González Armas Raquel , Rikkers Daniël , de Boer Hugo , de Feiter Vincent , de Haas Sebastiaan , Hartogensis Oscar , Mol Wouter , Janssens Martin , Heusinkveld Bert , van Heerwaarden Chiel , van Asperen Hella , Machado Luiz , Quaresma Cléo , Bastos Görgens Eric , Vilà Guerau de Arellano Jordi
Published: March 2024

Land-surface representations in weather and climate models simplify the characterization of vegetation as a single layer with bulk environmental conditions. This approach overlooks the vertical variability in leaf traits and environmental conditions within the canopy. This research explores the vertical variability of plant ecophysiology and environmental measurements within the Amazon tropical rainforest during daytime, specifically at the ATTO site, during the late dry season.To characterize the canopy and its vertical variability, we categorized the canopy into three layers: the top layer (approximately the upper third of the canopy, 18-27 m), the medium layer (approximately the medium third of the canopy, 9-18 m), and the low layer (approximately the lower third of the canopy, 0-9 m) where leaf gas exchange measurements were conducted. Utilizing these layers, we developed a multi-layer model representation that calculates water and CO2 fluxes based on within canopy on-site observations. We conducted sensitivity analyses of the rainforest multi-layer representation to discern the significance of capturing vertical variability in leaf traits and environmental conditions for deriving net fluxes of water and CO2 of the forest.Current results show that measured leaf traits exhibit vertical variation within the canopy, indicating larger productivity in the top layer compared to the medium and low layers. Environmental conditions, such as incoming radiation in the top layer, fluctuate due to cloud presence. Temperature peaks in the top layer and reaches a minimum at mid-canopy. This results in a non-uniform mixing of the canopy air, maintaining a stable layer within the forest canopy that can potentially affect the distribution of scalars within the canopy. Ongoing analyses explore the similarities and differences between the CO2 exchange between the multi-layer representation and CO2 fluxes from eddy covariance systems, as well as the sensitivity of the former to vertical variability in leaf traits and environmental conditions. By doing so, we aim to gain knowledge on the relevance (or irrelevance) of characterizing vertical variability in land-surface representations and on important processes that may not be well captured yet by land-surface representations.
Remote influence of (or on?) the Atlantic Meridional Overturning Circulation: A boundary pressure perspective.
Authors: Hughes Chris , Gururaj Saranraj
Published: March 2024

Pressure on the ocean's "sidewalls" - the global continental slope - is strongly dynamically constrained by the steep topography. As a result we find that, even in an eddy-rich ocean model, its variability exhibits coherence over many thousands of kilometres. Here, we examine the time-mean pressures and show how they reflect a combination of global wind-driven signals, interaction with the Antarctic Circumpolar Current and the AMOC, which is seen in the development of pressure around the boundary of the North Atlantic. The need for pressure to be single-valued around the global continental slope ensures that these factors must come to a consistent balance, which shows that two remote factors together must come into a balance with the AMOC. We elucidate how these factors interact, and illustrate them with diagnostics from a 1/12 degree ocean model.
Strenghts and limitations of common soil moisture products for operational drought monitoring
Authors: Gaona Jaime , Bavera Davide , Fioravanti Guido , Ciabatta Luca , Filippucci Paolo , Camici Stefania , Mosaffa Hamidreza , Puca Silvia , Roberto Nicoletta , Stradiotti Pietro , Brocca Luca
Published: March 2024

Soil moisture is a crucial state variable for understanding the water cycle. The increasingly available soil moisture data from remote sensing and models is rapidly facilitating improved hydrological analysis and evaluation of climate change impacts. To discern the degree of alteration of soil moisture, the patterns of spatiotemporal anomalies must be considered, but often product-specific uncertainties are overlooked. Such limitations are of particular concern for the operational monitoring and long-term evaluation of soil moisture.Among the sources of uncertainty jeopardizing remotely sensed and modeled soil moisture, this study evaluates over Europe (1) the heterogeneous spatial patches of validity, (2) the residual trends in the series, and (3) the sensitivity of anomaly detection to the baseline period of popular soil moisture products such as the Satellite Application Facility on Support to Operational Hydrology and Water Management (H SAF), the passive subset of the Climate Change initiative on SM (CCIp) and the European Drought Observatory (EDO) datasets.The inter-comparison of these remotely sensed and modeled soil moisture products by triple collocation analysis and against data of the international soil moisture network (ISMN) provides insightful results regarding (1) the contrasting patches of accurate soil moisture estimates, (2) the existence of residual temporal trends in the series, and (3) the differing sensitivity of the products to the baseline period for anomaly analysis. The factors impacting products are subject to debate, particularly concerning spatial and temporal consistency.Merged products combining H SAF, EDO and CCIp are also assessed to elucidate their potential and limitations for operational monitoring in comparison to individual products. Overall, the combined products equal or exceed the performance of individual products while incorporating specific benefits and drawbacks. Outcomes also inform about the best-performing product by area and period.All in all, the study illustrates the notable degree of consistency of commonly available soil moisture databases for multiple applications, despite some constraints, while highlighting the potential of merged soil moisture products for the operational monitoring of droughts within the European Drought Observatory (EDO) system.
Preliminary exploration of understory leaf area index inversion based on multi-angle remote sensing.
Authors: Wang Haojia , Zhang Xiaoping , He Liang , Geng Wenliang , Sun Weinan
Published: March 2024

    Soil erosion is one of the most widespread and serious environmental problems globally. Accurately obtaining understory vegetation parameters is a challenge for regional soil erosion assessment. This article introduces a method for obtaining understory vegetation Leaf Area Index (LAI) using multi-angle remote sensing techniques. Based on the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirectional Reflectivity Distribution Function (BRDF) data product (MCD43A1), the 4-scale geometric optical model was used to separate forest canopy and background reflectance. Combined with the measured understory LAI, a model for the inversion of understory LAI in the study area was developed. The results demonstrated that the background reflectance showed a similar seasonal variation trend as the reflectance of adjacent grassland, and significant difference was found between the background reflectance and the corresponding pixel total reflectance. Total reflectance was fitted separately with the measured canopy LAI and understory LAI. The coefficient of determination, R-square value between total reflectance and measured canopy LAI was 0.419, while the R-square value between total reflectance and measured understory LAI was only 0.053, it was indicated that the total reflectance mainly represents the information of the canopy. Established simple inverse models for the leaf area index of understory vegetation. the correlation between understory vegetation LAI and Ratio Vegetation Index (RVI) calculated based on background reflectance was the best, with the R-square value of 0.4733, Root Mean Square Error (RMSE) of 0.55, and Mean Relative Error(MRE) of 14.62%. This research can provide a method for evaluating understory vegetation in the quantitative estimate of regional soil erosion.KeyWords：Leaf area index; Multi-angle remote sensing; Background reflectance; Understory vegetation.
Biogeodynamics of narrow orogenic arcs and their biodiversity hotspots
Authors: Booth Rea Guillermo , Mas Peinado Paloma , Galve Jorge Pedro , Jiménez Robles Octavio , Azañón Jose Miguel
Published: March 2024

Narrow Orogenic Arcs (NOA) on Earth are oftenly biodiversity hotspots, where biogeographic evolution is influenced by tectonic forcing. However, the relationships between tectonic mechanisms intrinsic to NOA, landscape evolution and speciation forming biodiversity hotspots have not been dwelt with. Different mechanisms inherent to NOA, such as slab roll back, slab tearing, edge delamination, mantle upwelling and flow around subducted slabs, basin and archipelago migration and volcanic arc growth drive a dynamic landscape evolution that fosters processes of dispersal and allopatric-speciation. Here, we show this with examples from the Western Mediterranean and Caribbean. Slab tearing drives migrating waves of tectonic uplift and subsidence at the edges of orogenic arcs, coupled with crustal thickening followed by heterogeneous extension, forming endorheic basins and marine gateways among high-elevation ranges. Furthermore, vicariant events by isolation in high-elevation mountain ranges, internal drainage basins, stranded back-arc and volcanic arc archipelagos- seem to have driven the distribution and diversification of many taxa. Dispersal events would have been promoted by- drifting forearc archipelagos, changes of river courses (captures) and land bridges between continents, where ancient lineage dispersal followed by allopatric speciation-multiple diversification resulted in the current complex biological assemblages. The characteristic time and space migration of NOA, fosters recurrent processes of dispersal and vicariance, including in situ diversification through time. In this setting, long-time emerged parts of both drifting-forearc or stranded-backarc archipelagos represent both refuge and diversification centers where insular fauna may relate to distant, previously- attached land masses or islands. This is the case of drifting islands like the late Miocene Alboran archipelago in the Gibraltar arc or the Present Margarita island in the Caribbean, bearing biota with most common recent ancestors in the Balearic islands or the Central Coastal Range of Venezuela, respectively. Insular lineages may disperse by the closure of marine gateways between the mainland continents and drifting archipelagos, a process that may also drive the isolation of confined seaways, like the Mediterranean during the Messinian Salinity Crisis. Topographic uplift closing marine gateways or restricting seaways may occur by lithospheric rejuvenation, following delamination or detachment of subducted subcontinental mantle slabs and also by the growth of a volcanic arc. The emergence of new land and islands in the forearc domain, results in speciation and less species-rich communities in the direction of slab retreat. 
Historical drought occurrence on Slovak rivers during the period 1931–202
Authors: Miklanek Pavol , Pekárová Pavla , Bačová Mitková Veronika , Bajtek Zbyněk , Halmova Dana , Pekár Ján
Published: March 2024

In the last decade (2011-2020), Slovakia has experienced a significant decrease in flows in most river basins. The aim of this study is to statistically analyse the changes in the hydrological regime of selected Slovak streams based on observations over a 90-year period (1931-2020), using measured average daily discharges. Several regions in Europe, particularly in the Mediterranean area, including Spain, Italy, and Greece, have been affected by significantly dry years. The occurrence of dry years is not unusual, as extreme droughts have also occurred in the Danube River basin in the past, such as in 1863, 1921, 1947, 1992-93, and 2003. Our goal is to analyse changes in the low flow regime of rivers in Slovakia, which have long observation records. Understanding the low flow regime is one of the inputs for determining hydro-ecological limits, which is essential for maintaining and achieving good ecological status of surface waters. Several flow and non-flow characteristics were evaluated when assessing hydrological drought. Flow characteristics include: minimum average daily flows (in monthly or annual steps, over the entire period), M-day flows (the exceedance curve of average daily flows), minimum monthly and annual flows, and T-year minimum flows. Non-flow characteristics evaluated include changes in the timing of dry periods (date of occurrence), the number of low flow days, the longest drought episode, and the deficit volumes. Individual flow characteristics were calculated from the series of average daily flows. The trend analysis showed that in the given sub-catchments there is a decrease in the T-year minimum flows, as well as a decrease in the basic runoff. The comparison of the 100-year minimum specific runoff with the values of the specific base runoff shows that the 100-year minimum runoff can be up to ca. 4 times lower than the estimated specific base runoff in an extremely dry year. AcknowledgementThis work was supported by the project VEGA No. 2/0015/23 “Comprehensive analysis of the quantity and quality of water regime development in streams and their mutual dependence in selected Slovak basins”, and by the project APVV No. 20-0374 “Regional detection, attribution and projection of impacts of climate variability and climate change on runoff regimes in Slovakia”
The Max Planck Cloud Kite
Authors: Bodenschatz Eberhard , Bagheri Mohsen , Khodamoradi Hossein , Kupitzek Artur , Nordsiek Freja , Schettler Constantin , Thiede Birte
Published: March 2024

Most of the Earth's atmosphere is covered with clouds, which significantly affect incoming and outgoing radiation and thus the Earth's energy balance. Clouds are a source of considerable uncertainty in weather and climate models. Their size ranges from submillimeters, where cloud microphysics is important, to hundreds of kilometers, where they affect weather and climate. The complex coupling of cloud and turbulent flow dynamics at these scales makes clouds difficult to understand. In addition, several long-standing important puzzles, such as the existence and/or presence of cloud holes (regions without droplets) and the sharpness of cloud boundaries, remain unsolved. Given the high Reynolds numbers in atmospheric clouds (Re~10^6-10^9), laboratory-generated flows (with few exceptions) and direct numerical simulations are not yet capable of achieving cloud-like flow dynamics. Therefore, field studies and, in particular, airborne measurements performed far from the Earth's topographic influences can approach the correct range of parameter space relevant to naturally occurring clouds.We have developed the Max Planck CloudKite, which consists of a balloon-kite aerostat and a suite of scientific instruments for simultaneous measurements of aerosols and turbulence features in the atmospheric boundary layer and in clouds. Cloudkite is an independent platform capable of characterizing the atmospheric boundary layer and low-lying clouds within the boundary layer (
Energetic particle precipitation (EPP) influencing the electricity production by wind power in Northern Europe
Authors: Juntunen Veera , Asikainen Timo
Published: March 2024

Earlier studies have shown that geomagnetic activity, used as a proxy for energetic particle precipitation (EPP), can influence the wintertime weather conditions, e.g. temperature and wind speed, on the surface of the Earth. This effect is transmitted via the polar vortex, the westerly wind system circulating the polar area during winter, which can intensify due to increased EPP activity. Stronger vortex tends to cause mild, wet and more windy winter weather in Northern Europe while weaker vortex leads to cold, dry and less windy winter weather. The EPP effect on the vortex is greatly dependent on the phase of the equatorial stratospheric zonal winds, called quasi-biennial oscillation (QBO), and is stronger during easterly QBO winds.Previously it has been shown that the EPP effect on the polar vortex influences the wintertime electricity consumption in Finland that is greatly dependent on the outdoor temperature.  Since the strength of the polar vortex also affects the wind speed on ground, we now study how energetic particle precipitation would influence the electricity production by wind power.In general, the electricity production by wind turbines is proportional to the wind speed. Here we find that during easterly QBO winds the geomagnetic aa index (proxy for EPP) correlates significantly with the wintertime wind speed in Finland and Sweden and also with the wintertime electricity production by wind power. This correlation can explain about 30-40% of the inter-annual variations of wintertime wind power production in these countries during QBO-E winters.
Water-induced superplastic deformation and its mechanism of quartz 
Authors: zhan Lefan , Cao Shuyun , Dong Yanlong , Li Wenyuan , von Hagke Christoph , Neubauer Franz
Published: March 2024

The deformation behavior and mechanisms of mineral grains play a pivotal role in comprehending the solid-state rheological behavior of the lithospheric crust. However, the fluid present during the deformation processes of grains is often overlooked. The study presents a comprehensive analysis of water-induced superplastic deformation within deformed quartz veins exposed in the continental-scale exhumed Gaoligong shear zone by combining microstructure analysis with EBSD mapping and infrared spectroscopy. We observe fine-grained aggregates of quartz form micro-shear zones that are either localized at the rims or within the coarse clasts during deformation. The nucleation of these fine-grained zones is controlled by microcracks/fracturing, which are further associated with dynamic recrystallization. Numerous fluid inclusions are leaked and water is pumped into thicker fine-grained shear zones. The water migration plays a crucial role in accommodating boundary plasticity, with tiny water clusters being sealed within grain boundaries. The recycling of water is linked to a superplastic flow process, involving water influx, grain boundary sliding (GBS), accommodation of strain incompatibilities, and sealing of water. Our findings suggest that water migration into fine-grained aggregates within micro-shear zones not only restrict grain growth but also releases strain incompatibilities, enhancing grain boundary sliding. This process delays brittle fracturing of quartz, highlighting the significant role of water in influencing the deformation behavior of quartz. 
Mantle Oxidation Driven by the Redox Dynamics of the Mariana-Type Subduction
Authors: Duan Wenyong , Connolly James , van Keken Peter , Gerya Taras , Li Sanzhong
Published: March 2024

Oceanic plates descending into subduction zones transport a significant amount of oxidized material to both the subduction zone and the Earth's deeper layers (Wood et al. 1990). However, the specific mechanism of mass transfer and the corresponding flux released at different depths remains unclear. Through the use of numerical modeling and a coupled geochemical database, we examined redox dynamics in subduction zones, particularly focusing on Mariana-type subduction zones, representative of the modern plate tectonic regime (Yao et al., 2021).Our findings highlight two primary mechanisms in the mantle oxidation processes related to subduction. Firstly, desulfurization enables subduction fluids to carry substantial oxidation fluxes into the sub-arc mantle. Mass balance calculations emphasize the sufficiency of these fluxes in oxidizing both the arc magma and mantle wedge, with the hydrated mantle being the primary fluid contributor, followed by the altered oceanic crust. Secondly, partial melting of slab-top rocks, where Fe3+-rich melts from sediments and altered oceanic crust play a predominant role in the oxidation of the back-arc mantle. Importantly, during Mariana-type subduction, the majority of oxidation fluxes penetrate the deeper mantle with subducting slabs. According to our models, we illustrate that during the modern era of plate tectonics, the oxidation fluxes generated by Mariana-type subduction zones had a significant global impact on Earth's mantle redox evolution and the oxygenation of our planet.ReferencesWood, B. J., Bryndzia, T., Johnson, K. E. Mantle oxidation state and its relationship to tectonic environment and fluid speciation. Science 248, 337-345 (1990).Yao, J., Cawood, P. A., Zhao, G., Han, Y., Xia, X., Liu, Q., Wang, P. Mariana-type ophiolites constrain the establishment of modern plate tectonic regime during Gondwana assembly. Nat. Commun. 12(1), 4189 (2021).
Influence of initial soil carbon content on the stabilization of new carbon: a 2-year lab incubation study
Authors: Begill Neha , Don Axel , Poeplau Christopher
Published: March 2024

The hotly debated concept of carbon (C) saturation in mineral soils not only affects our understanding of soil organic matter (SOC) dynamics but also holds critical implications for negative emissions strategies. Many recent studies have indicated that soil’s capacity to store and stabilize C in mineral form depends on the initial SOC content, i.e., the soil C saturation deficit. According to these studies, low-C soils are suggested to have a higher potential for SOC storage compared to high-C soils. In light of these considerations, our hypothesis presents a different viewpoint, suggesting that initial C content in soils mainly affects the absolute loss of old carbon (following first-order kinetics), while it will not significantly impact the soil’s ability to stabilize new C. To investigate this experimentally, we selected soils from the first German Agricultural Soil Inventory with varying C contents (0.7–14.5%) and three different soil textures (light to heavy). These soils were then incubated in air-tight glass jars, where the same amount of 13C labeled litter was added, along with an unamended control of each sample. After two years, soils were dried and physically fractionated into mineral-associated organic carbon (MAOC) and particulate organic carbon (POC) using a size-cutoff of 20µm to find and δ13C as well as total SOC was measured. Here, we will present the first results from this lab incubation experiment, providing further systematic insights into whether the amount of initial carbon content or the ‘saturation C’ deficit truly affects the SOC dynamics with varying amounts of C contents in it.
Energy spectra of 300 keV to 1 MeV electrons from the SOHO Electron Proton Helium INstrument (EPHIN)
Authors: Jensen Stefan , Heber Bernd , Hörlöck Malte , Kollhoff Alexander , Kühl Patrick , Sierks Holger
Published: March 2024

The origins of energetic electrons with energies ranging from a few tens of keV to tens of MeV in the inner heliosphere are manifold. They include Galactic Cosmic Rays, Jovian electrons as well as sporadic Solar Energetic Electron (SEE) events. Their energy spectra provide insights into the acceleration at the source and transport processes in the heliosphere.The SOlar and Heliospheric Observatory (SOHO) was launched in December 1995 with the Electron Proton Helium INstrument (EPHIN) measuring electrons from 150 keV to several MeV. However, its measuring capability was reduced due to the loss of two detectors in 1997 and 2017, respectively. Thus from 2017 onwards only two electron channels, one in the range from 300 keV to one MeV and one “integral channel” that measures between 300 keV and 10 MeV.In this contribution we present a new data product for electron spectra based on the onboard histograms. This data product has the advantage of providing the total energy loss in the first two detectors with good statistics compromising energy loss determination via PHA data and counting statistics of the single channel. Using the so-called bow-tie method we were able to derive several energy channels between 300 keV and about 1 MeV. We present first results and compare them with instruments from other missions.The SOHO/EPHIN project is supported under Grant 50 OC 2102 by the German Bundesministerium für Wirtschaft through the Deutsches Zentrum für Luft- und Raumfahrt (DLR). This study has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 101004159 (SERPENTINE).   
Low-cost autonomous in-situ multiparameter optical sensor for climate-impacted catchment monitoring 
Authors: Regan Fiona , Power Sean , Briciu Ciprian , Richards Chloe , Delgado Adrian , Free Louis
Published: March 2024

There is a pressing need to monitor, measure, understand and mitigate causes of anthropogenic activities on our aquatic environments. In situ water monitoring sensors are vital tools for decision support and risk mitigation, pollution source tracking, and regulatory monitoring. To be fit-for-purpose, sensors must withstand the challenging marine environment and provide data at an acceptable cost. If networks of sensors are to become not only a reality but common place, it is necessary to produce reliable, inexpensive, rugged sensors integrated with data analytics.In this context, this work presents the design, development and testing of an affordable, robust and reliable optical sensor for continuous measurement of chemical and physical parameters in aquatic environments. Sensor electronics are housed in a marine grade watertight housing; the optical components are mounted inside a custom designed 3D-printed optical head which joins with the sensor housing.The sensor uses multiple optical detection modes (absorption, scatter and fluorescence) over a broad spectral range (280 nm to 850 nm) to measure parameters like turbidity, fluorescent dissolved organic matter (fDOM), Chlorophyll a (Chl a) and petroleum. Sensor analytical performance was established in the laboratory using analytical standards and in the field by comparison with a commercially available multi- parameter probe. The laboratory and field trials demonstrate that the sensor is fit-for-purpose and an excellent tool for catchment monitoring where rainfall-impacted soils can cause ecological disruption in the surface water. The sensor provides high frequency time-series data with unattended operation in-situ for extended periods of times.
Fluid-melt immiscibility during lower crustal melting recorded in the orthogneiss of Punta de li Tulchi,  Sardinia (Italy).
Authors: Ferrero Silvio , Cruciani Gabriele , Franceschelli Marcello , Fancello Dario , Rezaei Leila , Gresky Kerstin
Published: March 2024

Garnet in high grade rocks often contains primary melt (MI) and fluid inclusions (FI), fundamental to reconstruct the suprasolidus history of the rocks in which it occurs. MI and FI-bearing garnets have been recently found at Punta de li Tulchi, on the NE coast of Sardinia, Italy. They were identified in a single, decimetre-thick leucocratic body of overall granitic composition, hosted in migmatitic orthogneiss. Whereas in the host rock garnet is generally rare or absent, in the leucocratic body it reaches up to 5 vol% and occurs as subhedral grains up to several mm in size. Garnet composition is mainly almandine-spessartine (Alm60-70, Sps20-30 Pyr~7 Grs~3).The inclusions occur in clusters in the inner part of the garnet, i.e., they are primary in nature and therefore trapped during garnet growth. A preliminary investigation via optical microscopy and MicroRaman Spectroscopy (MRS) shows the presence of (at least) two types of inclusions. Type 1 inclusions are polycrystalline, ≤30 microns in size, and contain cristobalite +white mica ±carbonate, an assemblage overall consistent with their interpretation as nanogranitoids, or crystallized melt inclusions of anatectic origin. Type 2 inclusions contain two phases, i.e., liquid and vapour (70-30 vol% approximately). MRS display the presence of liquid H2O and a CH4-rich bubble, with minor amounts of CO2 and N2 detected in some cases. Often type 2 inclusions are characterized by the presence of a carbonate – either ankerite (CaFe carbonate) or rhodochrosite (Mn carbonate), based on the features of its Raman spectrum.Previous studies in the area suggest that these crustal rocks underwent high T metamorphism and re-melting in presence of fluid at 1.0 -1.1 GPa (Fancello et al., 2018) during the Variscan orogeny. The finding of melt-bearing garnets suggests that anatexis here also involved dehydration melting, at least locally, with formation of peritectic garnet. Moreover, this took place under conditions of primary fluid-melt immiscibility, as testified by the coexistence of MI and FI in the same cluster, a feature already found in many other nanogranitoid studies (see Ferrero et al., 2023). Finally, this is the first case study where nanogranitoids are found in almandine-spessartine garnet rather than in almandine-pyrope.ReferencesFancello, D., et al. Trondhjemitic leucosomes in paragneisses from NE Sardinia: Geochemistry and P-T conditions of melting and crystallization. Lithos, https://doi.org/10.1016/j.lithos.2018.02.023Ferrero, S., et al. H2O and Cl in deep crustal melts: the message of melt inclusions in metamorphic rocks. EJM, https://doi.org/10.5194/ejm-35-1031-2023
Intercomparison of high resolution ocean reanalysis products with observations, for exploring the spatiotemporal characteristics in the Indian Ocean
Authors: Paul Avinash , Padinjaratte Ayyapan Maheswaran , Karathazhiyath Satheesan
Published: March 2024

The Indian Ocean plays a crucial role in the global climate and marine ecosystems. Understanding its dynamics is essential for climate predictions, disaster preparedness, and resources management. Ocean reanalysis products offer valuable insights into these dynamics, offering a comprehensive representation of the ocean state over extended periods. However, the accuracy and reliability of these reanalysis products vary across different spatial and temporal domains depending on the model configurations and data assimilation techniques used. This study aims to inter-compare high-resolution ocean reanalysis products, namely GLORYS12V1 and Global Ocean Ensemble Reanalysis, with in situ and satellite observations to assess their performances in capturing spatiotemporal features of the Indian Ocean. Machine learning techniques will be employed to extract meaningful patterns and relationships from the vast oceanographic data, enhancing our understanding of the dynamics of the region. The study will focus on key oceanographic variables, including temperature, salinity, sea surface temperature (SST), sea surface salinity (SSS), and ocean currents. In situ observations from Conductivity Temperature Depth (CTD) profiles, buoys, and satellites will serve as the reference data. Overall the study will contribute to a comprehensive understanding of identifying regions and parameters where the reanalysis products exhibit significant biases or discrepancies compared to observations, Enabling researchers to refine model parameterization schemes, improve data assimilation techniques, and develop more accurate and reliable ocean models.
Pre-existing Fault Regulates the Distribution and Behavior of Hydraulic Fracturing-Induced Seismicity in southern Sichuan, China 
Authors: Zhang Fangxue , Wang Ruijia , Chen Yunfeng , Yu Hongyu
Published: March 2024

A thorough understanding of geological and hydraulic fracturing aspects can offer significant insights into the physical mechanisms governing earthquakes. In this study, we conducted seismic monitoring near a hydraulic fracturing well-pad in the southern Sichuan Basin. The monitoring adopts a dense seismic array that consists of 60 three-component stations, and last for a duration of 53 days. Accordingly, we resolved and located over 1,000 events (-1.43
Numerical fluid flow modelling in the context of CO2 sequestration on mid-ocean ridge flanks
Authors: Kremin Isabel , Rüpke Lars , Lange Isabel , Bach Wolfgang , Guo Zhikui
Published: March 2024

The majority of Earth’s basaltic volcanism occurs at mid-ocean ridges, where new ocean floor is created. Especially young oceanic crust, which is highly porous and permeable, is subject to regional off-axis hydrothermal circulation, which extracts large amounts of heat and impacts global water and chemical fluxes between the ocean and the lithosphere. Generally, seawater recharge and hydrothermal fluid discharge happen where the basaltic crust is exposed to the seafloor. This mode of circulation is usually referred to as outcrop-to-outcrop flow. Basaltic aquifers, overlain by impermeable sedimentary layers, can sustain outcrop-to-outcrop flow over distances of several 10s of kilometers. Basaltic rock formations are also explored for their potential to store injected CO2 with the added benefit that carbonation reactions promote the safe long-term storage. In this context, it is uncertain  whether natural hydrothermal flow between outcropping seamounts compromises a long-term storage or whether it will help to continuously expose injected CO2 to fresh reactive basaltic rock.Numerical fluid flow modelling on different scales is a powerful tool to understand the relations between off-axis hydrothermal circulation and CO2 storage. On the one hand, coupled heat transfer and fluid flow modelling of regional ridge flank flow can be performed at the kilometer scale and compared with heat flow observations. By using such regional models, we find that outcrop-to-outcrop flow arises if the permeability of the basaltic aquifer is larger 10-13 m2. This regional crustal permeability primarily controls the flow velocity and discharge mass fluxes. In the presence of outcrop-to-outcrop flow, the permeability and geometric shape of the outcrops further determine the direction of the flow. Secondly, the flow rates and fluid temperatures in the aquifer are influenced by the thickness of the sediment and the distance between the outcrops, respectively. These results based on regional models help to constrain flow patterns through the basaltic crust from seafloor observations, e. g. heat flow measurements in the sediment. Understanding these regional flow patterns is a compelling necessity in the context of CO2 sequestration on mid-ocean ridge flanks.On the other hand, in-situ carbon mineralization in porous basaltic crust can modify crustal permeabilities on local and regional scales, and thus influence regional circulation patterns. In this regard, we use pore scale numerical fluid flow simulations based on core samples in combination with laboratory experiments to parameterize the permeability evolution during carbonization reactions. Results of pore-scale modelling can be incorporated into the regional flow models to further enhance understanding of the interplay between off-axis hydrothermal circulation and carbon sequestration in mid-ocean ridge basalts.
EO4GRHO: A multi-satellite synthesis constraining the near-surface density profile of the Greenland Ice Sheet through time and space
Authors: Scanlan Kirk M. , Simonsen Sebastian B.
Published: March 2024

Satellite remote sensing is one of the few ways to comprehensively monitor changes in the Greenland Ice Sheet ‘s surface conditions through both time and space. From orbit, satellites can efficiently collect repeated measurements covering the entire ice sheet surface and elucidate the processes controlling how Greenland responds to a changing climate. Active radar and passive microwave measurements are especially valuable datasets, as cloud cover or illumination conditions are not limiting factors.In this vein, recent research has shown how near-surface properties (i.e., density and roughness) across Greenland can be derived through the Radar Statistical Reconnaissance analysis of Ku-band ESA CryoSat-2 and Ka-band CNES/ISRO SARAL surface echo powers. While this approach yields densities at individual depths in the near-surface, a fuller result would include constraining a continuous density profile as a function of depth. At the same time, L-band ESA SMOS passive microwave brightness temperatures are sensitive to the entire snow-firn-ice column. However, the inversion of brightness temperatures for a property of interest in a specific layer (e.g., snow wetness, density, etc.) requires numerous assumptions regarding the subsurface conditions.The EO4GRHO project seeks to merge these two approaches to investigate whether the inversion of SMOS brightness temperatures using a subsurface structure pre-conditioned with results derived from the analysis of radar altimetry surface echoes (i.e., density at known depth(s)) can provide a more complete picture of how Greenland Ice Sheet near-surface densities vary with depth, time, and space. Here, EO4GRHO leverages a decade (2013-2023) of contemporaneous CryoSat-2, SARAL, and SMOS measurements, makes use of modelled brightness temperatures from the Snow Microwave Radiative Transfer model software and, finally, hundreds of in-situ measurements. The ultimate aim of EO4GRHO is to operationally produce observation-based maps and time series for the near-surface density structure of the Greenland Ice Sheet that can be incorporated in future mass balance calculations.
Evaluation of the relation between soil biomass of arbuscular mycorrhizal fungi and glomalin-related soil protein in conservation agriculture
Authors: Thomopoulos Stamatios , Elsgaard Lars , Juhl Munkholm Lars , Ravnskov Sabine
Published: March 2024

Arbuscular mycorrhizal fungi (AMF) are indicators of soil health and are associated with various soil benefits, primarily linked to glomalin accumulation from hyphal turnover. However, the direct connection between glomalin-related soil protein (GRSP) and AMF has been questioned. In addition, conservation agriculture (CA) stands out as a pivotal plant production system that promotes agricultural sustainability and enhances soil quality.  In particular, the combination of minimal soil disturbance with residue retention has been linked with alterations in microbial biomass. The study aimed to explore the correlation between various fractions of GRSP and fatty acid fractions in the soil, along with examining the long-term impact of conservation agriculture practices on AMF biomass and GRSP content. Findings revealed a positive correlation between easily extractable (EE) GRSP and phospholipid fatty acid (PLFA) 16:1ω5, while no significant correlations were found for difficultly extractable (DE) or total GRSP fractions. These results highlight the complexity of GRSP dynamics and the need for further research on different fractions and their relation to AMF biomass. Additionally, the study demonstrated that mechanical soil management had a more significant impact on AMF hyphal biomass and EE-GRSP compared to residue management. Direct seeding, a reduced tillage approach, led to higher hyphal biomass and EE-GRSP, indicating AMF sensitivity to tillage intensity. This suggests that tillage practices exert a more substantial influence on AMF abundance and GRSP content than residue management.