bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the flow dynamics of a Plagioclase Ultraphyric Basalt- a case study from the Westfjords, Iceland
Authors: Jones Patrícia , Caracciolo Alberto , Marshall Edward W , Piispa Elisa Johanna
Published: March 2024

The volcanic landscapes of Iceland's Westfjords are marked by the intriguing presence of Plagioclase Ultraphyric Basalts (PUBs), distinctive lava formations that are a focal point of this research. Characterized by plagioclase contents so high (up to 50-60%) that they approach the crystallinity of a crystal mush, these formations offer a unique opportunity to explore the extreme end of lava crystallinity and the influence of abundant large plagioclase crystals on lava viscosity and flow. The main aim of this research is to understand how the abundance of large plagioclase crystals influences the viscosity and flow of lavas at the extreme end of lava crystallinity, as well as better understand the origin of the crystal cargo. The interplay between the crystals and the magma is crucial for better understanding the origins and flow characteristics of these volcanic formations. This is achieved through an interdisciplinary approach, combining petrographical and geochemical analyses, including Inductively Coupled Plasma (ICP) for major element trace element analysis, with Anisotropy of Magnetic Susceptibility (AMS) to determine the flow direction within the lava. This comprehensive method provides insights into the crystallization conditions of magmas and minerals, as well as the textural and compositional characteristics of the plagioclase crystals. The outcomes of this research are not only crucial for understanding the unique aspects of the Westfjords’ volcanic regions but also have significant implications for predicting volcanic hazards and refining magma dynamics models, thereby enhancing our ability to mitigate the impacts of volcanic activity. 
Plastic fruit stickers - changes of surface and structure during industrial composting
Authors: Braun Melanie , Groß Max , Mail Matthias , Wrigley Olivia , Debastiani Rafaela , Scherer Torsten , Amelung Wulf
Published: March 2024

In the past, large amounts of plastic particles have been found in compost, which often originate from the improper disposal of plastics in organic waste. A so far little-noticed input pathway of plastic in compost are so-called price look-up stickers made of conventional plastic. For example, such fruit stickers remain in the organic material despite sorting processes in the composting plant. However, little is known about alterations of price look-up stickers during industrial composting. Thus, this study aimed to investigate whether an industrial composting process leads to surface and structural changes of fruit stickers. For this purpose, fruit stickers made of polypropylene were placed on banana peels in an industrial composting plant and sampled after pre-rotting (11 days) and main rotting (25 days). Afterwards, composted stickers as well as non-composted stickers (control) were analysed by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), micro- and nano-computed tomography (CT). After industrial composting, all stickers showed signs of surface changes and degradation in the form of cracks, irregularities, and microbial colonisation on both the front and the back. Microbial growth was visible from day 11. Structural changes were observed, with large adhesions penetrating the sticker's surface and an increase in the volume from 16.7 to 26.3% during composting, accompanied by an increase in the carbonyl index. The delamination observed on some stickers after 25 days of composting indicates the formation of smaller microplastic or even submicron plastics.
A process-data duality driven hybrid model for improving flood forecasting
Authors: Xu Chengjing , Zhong Ping-an , Zhu Feilin , Xu Bin , Wang Yiwen , Yang Luhua , Wang Sen , Xu Sunyu
Published: March 2024

Floods are the most destructive events among natural disasters that restrict national economic development and threaten the safety of human lives. Accurate and efficient flood forecasting plays an important role in flood warning, flood risk analysis, and reservoir operation. Traditional flood forecasting tools provide fixed-value predictions. However, due to the complexity of reality and the limitations of human cognition, many inherent uncertainties are inevitably ignored. Therefore, it is of great significance to improve the existing hydrological forecasting models based on the full consideration of the uncertainty information input and migration transformation law. Probabilistic flood forecasting breaks through the conventional thinking of "single point, single value", and provides the probability distribution function of the forecast target variable.Process-driven hydrological models (HMs) are limited to simplified hydrological processes and have difficulty dealing with complex non-linear relationships between environmental variables and runoff. Data-driven models (DDMs) are good at capturing complex nonlinear relationships, but are overly dependent on data and lack consideration of physical mechanisms. Therefore, a hybrid model for probabilistic flood forecasting that couples the process-driven HM and DDM is proposed. HM can transfer the physical process information of observed runoff to the DDM, while DDM can extract additional nonlinear information not captured by HM, thus giving full scope to their respective advantages.The hybrid model treats the DDM as a residual model, that is, it corrects the residuals produced by the HM simulation, and the corrected values are added to the original hydrological simulation results to obtain the final runoff predictions. In order to quantify the uncertainty information in the forecasting process, the uncertainty in the HM parameters is used as the source of error, and the resulting input, parameter, and structural uncertainties in the DDM are investigated to construct a hybrid modelling framework that takes into account multiple sources of uncertainty. In addition to deterministic forecasts, this framework simultaneously provides interval forecasts and probabilistic forecasts for quantitative uncertainty assessment, which can provide more abundant and complete risk information for subsequent flood warning and reservoir operation.
Evidence of surface rupture associated with paleoearthquakes in the Trans Yamuna Segment of Northwestern Sub-Himalaya, India - Focus on the Sirmurital Active Fault 
Authors: Ghosh Swakangkha , Philip George , Narayanapanicker Suresh
Published: March 2024

Himalayan seismicity exhibits a bimodal mechanism with great earthquakes (+M8) rupturing the upper locked segment of the Main Himalayan Thrust (MHT) and blind earthquakes (up to Mw ~ 7.8) rupturing the down-dip section of the decollement. However, few imbricate and out-of-sequence active structures have been overlooked with limited research in the hinterland regions with respect to active fault mapping and paleoseismological trench excavations. The present study focusses on the western section of the Trans-Yamuna Active Fault (TYAF) in northwestern Sub-Himalaya, hosting the Sirmurital Active Fault (SAF). The SAF exhibits a distinctive south-side up trace, obliquely cross-cutting the Main Boundary Thrust (MBT).Satellite data, coupled with detailed field investigation confirms that the above fault dips 60˚ to the north, with a fault scarp of 40 m height. Minor strike-slip component is also confirmed with the presence of a subtle pressure ridge, and preliminary fluvial terrace mapping. Generation of a high-resolution Digital Elevation Model (DEM) from Cartosat-1 stereo pairs, and quantification with total station mapping of fault scarp further confirmed the terrace displacement. Subsequently, trench excavation (31 m in length) across the SAF at Sirmurital village provided compelling evidence of atleast two paleoearthquakes displacing and deforming Quaternary sediments along two identified fault strands. Soft-sediment deformation features complemented with injection features suggests its genetic link with paleoearthquakes. Radiocarbon dating analysis offers insights into the probable timing of the faulting events. Overall, the tectonic placement of the SAF provides a unique opportunity to document the occurrence of a normal fault in the hanging wall of a megathrust system and its potential to generate earthquakes in the highly populous mountainous belt of NW Sub-Himalaya. Therefore, the SAF along with the other associated faults, in the hinterland calls for detailed evaluation for a more comprehensive seismic hazard assessment. Keywords: Out of sequence; Sirmurital Active Fault; Cartosat-1; Paleoearthquakes; Soft-sediment deformation; Seismic hazard  
Insight into temporal and spatial coastal flooding through databases with historic meteorological data and national registry-reported natural disaster events
Authors: Kralj Erik , Kumer Peter , Meulenberg Cécil
Published: March 2024

One of the most significant consequences of climate change that is already felt today and will be felt even more in the future is the frequency and severity of natural disasters. Of those, sea-caused floods and storm surges will have the biggest impact on coastal communities, which will be further potentiated on one hand by the sea level rise and on the other by increasing coastal population and economic activity which will make those communities even more vulnerable. As the underlying causes of extreme weather events cannot be circumvented, alternatively it is feasible to decrease the flood vulnerability of most affected areas and implement the right flood control measures. But before any steps can be taken in this direction it is of the utmost importance to analyse the patterns of such events and to establish an early warning system that will allow the local community to respond to such events in a timely manner. Slovenia keeps records on natural disasters to inform civil protection services for performing mobilizing actions during calamity interventions, and an environmental agency that keeps records on past weather conditions through various stationary land and sea sensors. In the case of coastal storms, the latter informs the first, as a matter of public safety during potentially emerging extreme weather conditions giving rise to coastal flooding. Piran, a coastal historic town situated on a narrow peninsula surrounded by North Adriatic Sea waters, is especially vulnerable to coastal floods with 7.3 floods per year on average occurring generally from October through March. Low-lying parts are especially flood-prone, of which the areas below 2.3 m above sea level cover a large percentage of the town covering a mixture of residential, commercial and cultural heritage buildings. With no long-term preventative sustainable measures yet in place and urban sensors 4 to 15 km away from the town, the early warning system does not rely on local climate services but uses general national forecasts. Here we combine the historic records on past flooding events and environmental data to understand the local flood patterns in Piran. This study aims to offer a more nuanced understanding of flood patterns in Piran through the combination of localized field-report and sensor systems from national databases to reliably enhance the precision of flood predictions. The study underscores the pivotal role of accurate, localized data to be extracted from national or regional registries where available that aid in fortifying coastal towns against the escalating impacts of climate change, safeguarding both the inhabitants and the invaluable architectural heritage of historic areas.

 
AMADEE and PolAres - Programmatic considerations for Mars analog missions
Authors: Groemer Gernot , Oezdemir-Fritz Seda , Knie Julia , Tlustos Reinhard , Stumptner Willibald
Published: March 2024

Human-robotic Mars missions are envisioned for no earlier than the early 2040ies, including surface sojourns of at least one month. Since the Apollo-era, analog studies have been supporting planetary surface missions as an effective and efficient tool to prepare for future missions to Mars. Mars analogs on Earth are used to understand processes on the Red Planet from the (geo)scientific point of view, to optimize operational field research in analog environments is an established tool for testing scientific workflows, evaluating operational concepts, and optimizing the efficiency and safety of planetary surface missions.Since 2006, the Austrian Space Forum conducted 14 Mars analog field simulations as part of its decadal PolAres and AMADEE programs, conducting 200+ experiments from the fields of geoscience, human factors and robotics to study workflows, technologies and science strategies pertinent to the search for extinct or extant traces of life.We present an overview on the science logistics, experiment selection and onboarding process and programmatic strategies of organizing interdisciplinary, multinational mars analog campaigns, involving typically 200-250 researchers from 25+ nations. The focus is on the scientific workflows balancing operational constraints coordinated and scientific needs via a dedicated Mission Support Center, research institutions and field crews.The work of the Austrian Space Forum is presented in the context of the recently established International Guidelines and Standards on Analog Research (IGSA) and the ESA Topical Team on Human Factors in Analog Research.
Paleoceanographic implications from Middle to Late Miocene benthic foraminifera in the southeastern Indian Ocean (ODP Site 752)
Authors: Hechemer Tamara , E. Piller Werner , Puentes-Jorge Xabier , Lyu Jing , De Vleeschouwer David , Christensen Beth , M. Bialik Or , Grunert Patrick , Drury Anna Joy , Auer Gerald
Published: March 2024

Concerning climatic conditions during the Miocene Climate Optimum (MCO), global temperatures were about 3-4°C warmer than modern, and characterized by globally lower ice volume. Indian Ocean Sub-Antarctic Mode Water (SAMW) is primarily formed south of 30°S and is the primary return path for deep waters to the surface, migrating and intermixing northwards at Intermediate Water (IW) depths. Today, the SAMW carries access nutrients into the lower latitudes, strongly impacting latitude productivity. During warmer climates, decreasing sea ice may increase nutrient trapping in the Southern Ocean, reducing the nutrient flux through SAMW into the lower latitudes. Thus, the MCO may indicate future climate, nutrient transport, and SAMW formation by exploring differences between cooler (modern) and warmer (MCO) climates.Ocean Drilling Project (ODP) Site 752, located on Broken Ridge in the southeastern Indian Ocean at a water depth of 1086.3 m, is a key location for investigating changes in IW conditions in the Indian Ocean after the MCO and the Middle Miocene Climatic Transition (MMCT). In particular, the reactions to global warming and the reorganization of oceanic and atmospheric circulation following the MCO and MMCT can be detected. This also includes the analysis of SAMW, Antarctic Intermediate Water (AAIW), and Tasman Leakage (TL).The present study aims to reconstruct paleoenvironmental conditions and bottom-water oxygenation at Site 752 during the Middle to Late Miocene (15-8 Myrs). To achieve this, we apply benthic foraminifera assemblages as proxies for bottom water oxygenation, for example, enhanced Benthic Foraminifera Oxygen Index (eBFOI), paleoproductivity, and stable carbon and oxygen isotopes.Initial results in the Middle to Late Miocene show an occurrence of oxic benthic foraminifera at a relatively constant abundance, especially in the early Late Miocene. In addition, in a relatively high oxic environment, an increase of dysoxic conditions occurred during the early Late Miocene, with peaks of abundance in dysoxic and deep infaunal benthic foraminifera. A co-occurrence of infaunal dysoxic and epifaunal oxygen-rich species is accompanied by enhanced current winnowing and an increase of nutrient flux during the Late Miocene (Lyu et al., 2023; DOI: 10.1029/2023PA004761). These data indicate that during the Late Miocene, since approximately 10 Ma, the strengthening of SAMW and AAIW formation resulted in notable changes in bottom-water conditions at Broken Ridge, such as increased current winnowing. The observed changes in IW are potentially linked to the shift of the southern hemisphere westerlies towards the north and the subsequent northward migration of the frontal system in the southern hemisphere around Antarctica after 12 Ma.
Global continental hiatus surfaces as a proxy for tracking dynamic topography since the Upper Jurassic
Authors: Vilacís Berta , Brown Hamish , Carena Sara , Bunge Hans-Peter , Hayek Jorge N. , Stotz Ingo L. , Friedrich Anke M.
Published: March 2024

Mantle convection is a fundamental process governing the evolution of our planet. Buoyancies in the mantle induce horizontal and vertical motion of the Earth’s lithosphere, which can be mapped using independent geological datasets. Positive surface deflections induced by mantle convection create erosional/non-depositional environments which lead to gaps (hiatuses) in the stratigraphic record, while negative deflections provide accommodation space for sedimentation to occur. We use continental- and country-scale digital geological maps and regional and local stratigraphic studies at the temporal resolution of geological series (ten to tens of millions of years) to map the distribution of hiatus through geological time.Here we present global continental hiatus surfaces since the Upper Jurassic. We find that they vary inter-regionally at timescales of geological series and that they correlate with known mantle dynamic events. For example, we tend to observe the appearance of a hiatus surface before the arrival of a mantle plume. In Europe, we mapped a large-scale sedimentary hiatus during the Paleocene, prior to the arrival of the Iceland plume. In Africa and South America, we found a widespread absence of the Upper Jurassic prior to the arrival of the Tristan plume. This pattern can be seen as characteristic of plume-induced dynamic uplift. We observe a sea level signal during some geological series, such as in the Oligocene, when there is a global increase of hiatus areas, coinciding with the onset of Antarctic glaciation and associated sea level drop. At other times, we find that the hiatus areas evolve differently for different continents, precluding their interpretation as an eustatic signal. Spectral analysis shows that hiatus surfaces have shorter wavelengths than no hiatus surfaces, requiring higher spherical harmonic degrees to describe the geological series with larger amounts of hiatus. These include the Upper Jurassic, the Paleocene, the Oligocene and the Pleistocene.Our results imply that a key property of time-dependent geodynamic Earth models must be a difference in timescale between mantle convection itself and resulting dynamic topography. Moreover, they highlight the importance of continental-scale compilations of geological data to map the temporal evolution of mantle flow beneath the lithosphere, which can provide powerful constraints for global geodynamic models.
Sea Surface Temperature Retrievals in Heavy Precipitation From AMSR-2 Microwave Measurements
Authors: Jelenak Zorana , Chang Paul , Alsweiss Suleiman
Published: March 2024

The first satellite microwave sea surface temperature (MSST) estimates were provided from TRMM Microwave Imager radiometer on board of Tropical Rainfall Microwave Mission in 1997. Since then the MSST became on of one of most sought after parameters for new microwave missions in both operational and research communities. In that respect the WindSat, AMSR-E, ASMR-2 and GMI instruments all empployed either C- or X-band channels or both in order to provide the SST measurements. While the resolution of MSST is relativly course due to utilization of the low frequency channels, the main advantage of the MSST is in its ability to fill the gap in observations in cloud covered regions. While However the SST coverage is still spars heavy clouds and precipitation areas.To maximaze utility of MSST for operations we investigated different combinations of microwave brighntess temperatures that minimize precipitation effect on measurements and maximaze its sensitivity to SST. Guided by this goal we developed a statistically based algorithm that relies on three empirical quantities utilizing linear combinations of 6, 10 and 18GHz vertically and horizontally polirized channels. This approach allowed us to come up with the unique, first of a kind MSST product from AMSR-2 microwave ocean observations that provides SST estimates even in the heavy precipitation areas such as one observed within Tropical Cyclones. Utilization of higher frequency channels had an added advantage of increasing the the MSST resolution relative to products that utilized only 6 or 10GHz measurements. Another added advantage was substantially minimized sun glint areas that were traditionally excluded from measurements swaths and resulted in substantially reduced coverage in the southern hempisphere.The measurement technique, validation results and data availability will be discussed and presented.
Structure and Dynamics of the Porcupine Magma-Poor Continental Margin from new Ocean Bottom Seismometer Data
Authors: Yusuf Ibrahim , M Jones Stephen , Reston Tim , Funck Thomas , M O'Reilly Brian , R Hopper John
Published: March 2024

The Porcupine Basin, situated in the North Atlantic, serves as a unique natural laboratory for investigating the temporal evolution of magma-poor rifts. Notably, the basin exhibits a progressive increase in the total degree of stretching from north to south, offering a valuable opportunity to interpret its structure in terms of the temporal evolution of magma-poor rifted margins. This study, as part of the broader PORO-CLIM project, focuses on Profile 2 to construct a whole-crustal seismic velocity model and integrate it with existing data to unravel the complete rifting history of the Porcupine Basin.In the northern region, Reston et al. (2004) identified a detachment fault, the P-reflector, indicating substantial rifting  [1]. Recent analyses by Prada et al. (2017) extended this understanding to the central basin, revealing progressive crustal thinning and mantle serpentinization [2]. However, the southern sector remains largely unexplored. This project aims to capitalise on newly acquired Ocean Bottom Seismometer (OBS) data from PORO-CLIM Profile 2 to image the deep crustal structure and complement this with basement mapping of the southern Porcupine Basin using industry 2D seismic data.Seismic refraction data from 20 OBS along a 226 km transect form the basis for constructing a comprehensive crustal velocity model. Utilising the RAYINV modelling package, a layer-by-layer forward modelling approach is employed to correlate calculated and observed travel times. Concurrently, structural mapping using long-offset 2D seismic reflection data assists in delineating major faults and regions of mantle unroofing, contributing to the understanding of the Porcupine Basin's subsurface. Preliminary findings reveal extreme crustal thinning and asymmetry, highlighting north-to-south crustal thinning and the emergence of the P-reflector in the southern region of the Porcupine Basin.[1] Reston, T.J., Gaw, V., Pennell, J., Klaeschen, D., Stubenrauch, A. and Walker, I. (2004). Extreme crustal thinning in the south Porcupine Basin and the nature of the Porcupine Median High: implications for the formation of non-volcanic rifted margins. Journal of the Geological Society, [online] 161, pp.783–798.[2] Prada, M., Watremez, L., Chen, C., O’Reilly, B.M., Minshull, T.A., Reston, T.J., Shannon, P.M., Klaeschen, D., Wagner, G. and Gaw, V. (2017). Crustal strain dependent serpentinisation in the Porcupine Basin, offshore Ireland. Earth and Planetary Science Letters, [online] 474, pp.148–159.
Leveraging climate data at different spatial scales via machine learning to improve sub-seasonal drought predictions
Authors: Giuliani Matteo , Bosso Francesco , Bertini Claudia , Solomatine Dimitri , van Andel Schalk Jan
Published: March 2024

Droughts are one of the most dangerous natural hazards affecting today societies, with an economic impact amounting to over 9 billion euros per year in Europe. Drought events usually originate from a precipitation deficit, which can then cause water shortages, agricultural losses, and environmental degradation. Despite the numerous efforts and recent advances in extreme events forecasting, the sub-seasonal time scale still represents a challenging lead time for state-of-the-art hydroclimatic predictions. In this case, the reference period is short enough for the atmosphere to retain a memory of its initial conditions, but also long enough for oceanic variability to affect atmospheric circulation. However, the relative contribution of climate teleconnections and local atmospheric conditions to the genesis of total precipitation at sub-seasonal scale remains unclear.In this work, we aim to address this gap by using Machine Learning (ML) to combine the information extracted from teleconnection patterns, global climate variables, and local atmospheric conditions to produce sub-seasonal drought forecasts. Specifically, we implemented a first ML pipeline that uses correlation maps to select relevant grids of global Sea Surface Temperature, Mean Sea Level Pressure, and geopotential height at 500 hPa from the ERA5 reanalysis dataset, which are spatially aggregated via Principal Component Analysis and combined with a set of local variables in the considered region. The second ML approach extends our analysis by explicitly considering the potential role of teleconnection patterns, including North Atlantic Oscillation, Scandinavian oscillation, East Atlantic oscillation, and El Niño Southern Oscillation, to identify different forecast models - in terms of both input variables and model parameters – for the different phases of the climate oscillations and for each month of the year. The resulting combination of global and local variables is then used as input in different ML models, including both feedforward neural networks and extreme learning machines.Our framework is developed within the CLImate INTelligence (CLINT) project and tested in the task of predicting the total monthly precipitation in the Rijnland area (Netherlands). The resulting ML-based forecasts are then benchmarked against state-of-the-art dynamic forecast products, i.e. the ECMWF Extended Range forecasts. Our findings indicate that combining global and local climate information into ML-based forecast models significantly improves state-of-the-art drought forecast accuracy, thus representing a promising option to timely prompt anticipatory drought management measures.
 Investigation of Pore-Fracture Charging Sequences in Tight Reservoirs Based on Multi-Stage Pressure Injection Experiments with Wood's Alloy
Authors: Liu Jipeng , Jiang Zhenxue
Published: March 2024

The tight sandstone reservoir features the development of micro- and nano-scale pores and micro-fractures, contributing to a complex pore-throat structure. This complexity results in an indistinct charging sequence of oil and gas in different types of storage spaces during the accumulation period, thereby escalating the challenges associated with the exploration and development of tight oil and gas. Focusing on the Fuyu oil reservoir in the northern Songliao Basin, this study integrates large-field-of-view stitched scanning electron microscopy with mineral surface scanning techniques. Innovatively, a micro-nano scale comprehensive reservoir evaluation method, incorporating both pores and micro-fractures, is proposed. Within the study area, three predominant pore-fracture combination types are identified: intergranular pore-clay mineral shrinkage fractures, intergranular pore-brittle mineral intergranular fractures, and intragranular pore-clay mineral shrinkage fractures. Building upon this, Wood's alloy, exhibiting high-temperature rheological properties, is injected into rock cores under various pressure conditions. It is observed that with increasing injection pressure, the alloy injection process demonstrates a structured order, with a clear preference for charging intergranular pore-fractures over clay mineral-related pores. Furthermore, the alloy injection efficiency curve exhibits a distinctive parabolic shape. Based on the characteristic properties of Wood's alloy and crude oil, the injection pressure is equivalently transformed, reconstructing the micro-scale charging process of tight oil under reservoir conditions. Consequently, a sequential charging model for tight reservoirs is established, encompassing micro-nano-scale intergranular pore-fractures, nano-scale clay mineral intragranular pores, and shrinkage fractures. This model considers parameters such as source-reservoir pressure difference, storage space type, fluid properties, etc. From both qualitative and quantitative perspectives, it clarifies the microscopic accumulation sequence of tight reservoirs. This research focuses on the development of a new multi-scale evaluation method for tight reservoir storage spaces, combining fluid injection with visualization technology. The findings are crucial for the microscopic sweet spot evaluation and efficient development of tight reservoirs.
Post-processing of short to medium range NWP based reference evapotranspiration forecasts using Machine Learning Techniques across the Indian subcontinent
Authors: Saminathan Sakila , Mitra Subhasis
Published: March 2024

The main objective of this study is to evaluate the efficacy of machine learning (ML) techniques in improving numerical weather prediction (NWP) based reference evapotranspiration (ETo) forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF) at short to medium range time scale across different zones in the Indian region. The meteorological hindcasts from ECMWF are used to estimate ETo forecasts using the FAO Penman-Monteith equation. Thereafter, the raw forecasts are post-processed using two ML techniques: Support Vector Regression (SVR) and Extreme Gradient Boosting (XGBoost). The ML techniques are applied to rawETo forecast in order to improve its reliability and accuracy. The raw and ML post-processed ETo forecasts are assessed using deterministic evaluation metrics. Results highlight that ML post-processed ETo forecasts have superior skill than raw ETo forecasts. The highest improvement is reported in the Himalayan regions, and the XGBoost model outperformed the SVR model across all zones. The outcomes of this study has implications towards agricultural water management and irrigation scheduling over the Indian subcontinent.
Small fractures in marine muds indicating nascent hydrate formation
Authors: Martin Saffron , Brunet Morgane , Cook Ann
Published: March 2024

On many marine continental slopes, gas hydrate has been observed filling fractures in marine muds.  Fracture filling hydrate likely forms because the pore size of clays is small, and therefore, hydrate can only form in secondary porosity; some scientists have suggested the process of hydrate formation causes these fractures to form. On borehole image logs, these fractures were found to have high angles and form in 3D planes. While the plane is filled with hydrate, the overall bulk concentration of hydrate can be quite low. In X-ray computed tomography (XCT) images, similar high angle planar fractures have been found that cut through whole round core. Typically, these fractures appear to have diffuse, wispy edges in comparison to other fractures that form due to core expansion or core collection. We have found new, smaller 3D planer fractures that are likely the initial stages of hydrate fracture formation. These hydrate-filled fractures range in lengths from around 10 – 400 mm with widths ranging from 0.5 - 15 mm. The fractures tend to be well oriented, having a high dip angles (>40°) and going through the whole core on a plane. The wispy, diffused edges suggest sediment displacement due to the hydrate formation process and are distinctly different than other fractures seen in the XCT data. The fractures must be unconnected to any other break in the sediment, existing solely as a fracture with a high dip angle, with diffused edges.In New Zealand, IODP Site 1517, we found that these specific fractures appear near the sulfate-methane transition zone (SMTZ). We hypothesize that if more sediment cores and XCT data were collected through and close to the SMTZ, more similar small fractures would be imaged, potentially indicating nascent gas hydrate formation.
New Open-Source Python libraries for Radar Interferometry Data Processing and Analysis
Authors: Ku Ou , Alidoost Fakhereh , Chandramouli Pranav , van Lankveld Thijs , Nattino Francesco , Grootes Meiert , van Leijen Freek , Hanssen Ramon
Published: March 2024

Modern satellite missions continuously generate extensive observation datasets for Interferometry Synthetic Aperture Radar (InSAR), which is a crucial technology for monitoring ground surface deformation. The efficient processing and analysis of these extensive InSAR datasets poses two computational challenges: 1) the growing volume of the datasets that needs to be incorporated into the data processing workflow, and 2) the integration of contextual information associated with the InSAR data to reveal the mechanisms driving deformation.   

To address these challenges, we present two open-source Python libraries: SARXarray [1] and STMTools [2]. They facilitate common InSAR data processing tasks and are developed as extensions of the open-source Python library, Xarray, which handles labelled multi-dimensional arrays and is well-suited to the space-time nature of InSAR data. SARXarray is designed to work with coregistered raster stacks, such as SLC or interferogram stacks, offering functionalities like multi-looking, coherence computation, and coherence scatterers selection. STMTools, on the other hand, focuses on large spatio-temporal datasets in the form of a Space-Time Matrix (STM) [3], for instance, coherent scatterers. It can query background contextual data, such as geospatial polygons, and add the attributes-of-interest to the corresponding STM. Furthermore, both SARXarray and STMTools support data chunking and lazy evaluation, enabling the scaling up of the data processing pipeline and parallel processing of larger-than-memory data across various computational infrastructures. 

[1] Ku, O., et al., sarxarray [Computer software]. github.com/MotionbyLearning/sarxarray 

[2] Ku, O., et al., stmtools [Computer software]. github.com/MotionbyLearning/stmtools 

[3] Bruna, M. F. D., van Leijen, F. J., & Hanssen, R. F. (2021). A Generic Storage Method for Coherent Scatterers and Their Contextual Attributes. 
Effect of passive warming (soil translocation) on 18O CUE and soil enzyme activity along a tropical forest elevational gradient
Authors: Song Bin , Huang Aiwei , Z.Mganga Kevin , Tuure Juuso , Poeplau Christopher , Luo Xuhui , Karhu Kristiina
Published: March 2024

The impact of global warming on soil processes is a critical area of concern. Limited studies have investigated soil organic carbon (SOC) dynamics' adaptation to warming. This poses a great challenge in assessing and understanding terrestrial C cycle response to climate change. Carbon Use Efficiency (CUE), indicating the proportion of metabolized organic C allocated to microbial biomass growth, is a pivotal regulator governing the fate of soil C. Moreover, our understanding of fundamental drivers of microbial CUE is largely elusive and inconclusive, especially in tropical ecosystems.To address these knowledge gaps, we translocated top soil samples (10 cm deep soil cores) from two higher elevation sites (Vuria, 2000 m a.s.l, and Ngangao, 1800 m a.s.l) to a lower site (Macha, 1600 m a.s.l) along a moist montane rain forest gradient in Taita Hills, Kenya. Utilizing an 18O-water tracing approach, we examined the changes in microbial CUE in response to approximately three years of experimental warming. We also measured enzyme activities and conducted a 6-month laboratory incubation (15°C and 25°C) to study temperature sensitivity in native and translocated samples.Our hypotheses were: (i) Both microbial CUE and C related enzyme activities would decrease, however, N- and P- cycle enzyme would increase along an altitudinal gradient toward the top of the Taita Hills, primarily governed by soil C and N availability; (ii) passive warming by soil translocation would result in higher CUE in translocated soils compared to native soils; (iii) At lower temperatures, soil microbial CUE is expected to decrease due to microbes allocating increased energy towards synthesis of enzymes involved in nutrient acquisition, while reducing C investment towards their growth.Initial findings have revealed significant distinctions in enzyme activity profile due to elevation and temperature effects. Specifically, β-glucosidase and acid phosphatase activities increased and decreased along the elevation, respectively. Consistent with our hypothesis, enzyme activities and microbial CUE were higher in translocated soil than native soil. The six-month incubation had a similar effect on translocated soils and lower temperature increased the microbial CUE. In summary, our study indicates that passive warming alters microbial temperature adaption and underscores the influential role of soil enzyme activities in regulating microbial CUE. We suggest that soil microbiome at lower temperature indicates greater need for nutrients and energy. Our results highlight the need to investigate a wide variety of temperature influence on tropical soils in order to better understand and predict how the changing climate will affect C and nutrient cycling.
Understanding spatio-temporal variations in crop water consumption: Applying the WF Methodology Integrated with the SWAT Model
Authors: Muratoglu Abdullah , Demir Muhammed Sungur
Published: March 2024

Agricultural activities account for a significant portion of global water consumption, emphasizing the need to improve water productivity in this sector. This can be achieved through the implementation of effective agricultural management practices, such as optimizing crop patterns, adjusting irrigation methods, and improving fertilization practices. The Water Footprint (WF) concept offers a comprehensive approach to assessing water consumption in agriculture, considering different types of water use. By integrating the WF methodology with hydrological modeling programs, a more detailed analysis of water consumption patterns can be achieved, overcoming previous limitations in understanding agricultural water use. This study aims to assess the water consumption patterns of maize under different spatio-temporal dynamics. The WF of maize, including blue, green, and grey components, was calculated using the Soil and Water Assessment Tool (SWAT) model in the Ceyhan Basin (Turkey) between 2011-2020. The study outputs indicated considerable spatial and temporal variations, with a total WF ranging from 350 to 1320 m3/t. Green WF (61-385 m3/t) is found to be less dominant in maize production across the basin, while blue water emerges as the primary component (25 to 870 m3/t). In this study, the utilization of the SWAT model provided detailed spatio-temporal results, allowing for adjustments in agricultural patterns. We obtained that, optimizing the cultivation regions of maize within the Ceyhan Basin has the potential to reduce the total WF by approximately 26% and the blue WF by 47%. This optimization could result in an annual saving of around 135 million m3 of irrigation water. Furthermore, the study also analyzed temporal water consumption patterns. The findings highlight the significant potential for water conservation in agricultural activities through the spatio-temporal optimization of blue and green water, taking into account hydrological characteristics.
Geomorphic evidence for along-margin ice flow from Melville Bugt slope, west Greenland
Authors: Klotsko Shannon , Hatfield Rob , Reilly Brendan , Mix Alan , Jennings Anne , Gregory Erin , Stoner Joe , Walczak Maureen , Donnenfield Jonas , Fritz Cara , Hough Alice , Kelleher Robert , Monito Lindsay , Olarte Paloma , Siragusa Megan , Stelling Katherine , Vonahme Tobias
Published: March 2024

In summer 2023, the Baffin Bay Deglacial Experiment (BADEX) completed a 33-day cruise focused on the west Greenland margin; the overarching goal of this project is to investigate the evolving ocean and ice conditions along the west Greenland ice sheet from the last glacial maximum through the deglaciation. The cruise collected seafloor and sub-seafloor data, as well as water and plankton samples, with the aim of establishing 1) the timing and extent of warm Atlantic water incursion along the north-western Greenland margin; 2) the phasing of the initial ice margin retreat relative to oceanic and atmospheric changes; 3) the role of local or regional ice shelves in buttressing trough-bound outlet glaciers; and 4) the influence of regional geology, geomorphology, and ice dynamics on ice-margin retreat. Here, we present results from the ~600 km of new multibeam sonar data collected on the slope just north of the Melville Bugt trough mouth fan (TMF). The margin in this area curves landward, forming a crescent-shaped, submarine amphitheater that contains a range of bathymetric features, which vary in form with water depth and their proximity to the TMF. This includes a series of contour-following ridges that occur in depths from ~1000 to ~450 meters below modern water level. These ridges are more prominent farther away from the TMF but are more numerous closer to the trough. They are interpreted to be of glaciogenic origin, potentially formed by an ice shelf, fed by the trough, that flowed to the north and grounded on the slope. These ridges and other bathymetric features, extending up to 2000 meters water depth will be discussed. These results add to our understanding of the ice margin configuration in northern Baffin Bay during and after the last glacial period.  
Fine-scale crustal velocity structures along and across the Lucky Strike segment of Mid-Atlantic Ridge from full waveform inversion of wide-angle seismic data
Authors: Wang Zhikai , Minshull Tim A. , Singh Satish C.
Published: March 2024

The 70-km long Lucky Strike segment at 37oN on the Mid-Atlantic Ridge is characterized by a well-defined median valley bounded by ridge-ward dipping faults and a volcano located at the segment centre. The central volcano is fed by an axial magma chamber at ~3 km depth below seafloor. Away from the axial valley, the seafloor morphology is dominated by fault-controlled abyssal hills. Several active hydrothermal vents have been observed on the summit of the Lucky Strike volcano, and the axial magma chamber has been suggested to be the source supplying heat. Seismic velocities of the subsurface provide constraints on porosity and thus permeability, as well as the distribution of hot or molten rock. Therefore, determining fine-scale velocity structure of crust formed on the Lucky Strike segment is critical for understanding the interactions between magmatic, tectonic and hydrothermal processes during crustal accretion.We performed two-dimensional elastic full waveform inversion (FWI) to wide-angle ocean bottom seismometer (OBS) data to constrain the velocity of the crust beneath a profile along the entire Lucky Strike segment and another across the axis extending to ~50 km distance on both flanks. The seismic data were acquired during the SEISMOMAR survey in 2005. The OBS intervals vary between 4.5 and 14.0 km, with denser OBS deployed around the central volcano. Both profiles were shot multiple times, with shot spacings of 425 m and 150 m. Starting models for FWI were obtained from travel time tomography of the OBS dataset. The FWI results show a low velocity anomaly (LVA) beneath the Lucky Strike volcano at ~3 km depth below seafloor, just below the axial magma chamber reflector imaged in seismic reflection data. The LVA extends ~10 km along axis and ~4 km across axis and is ~0.7-1 km thick in depth. Taking the depth of 6.5 km/s velocity contour as the base of upper crust, the upper crust thickens along the axis from 2.2 km at segment centre to 3.5 km at the segment ends. In contrast, the crustal thickness reduces from ~8.3 km at the segment centre to 4.0-4.5 km at distal ends, assuming the 7.1 km/s velocity contour corresponds to the crustal base. This contrast is due to the significant reduction in lower crustal thickness towards the segment ends, where the upper-to-lower crustal thickness ratio increases from ~0.4 to >3.5 from segment centre to ends. These observations suggest the presence of focused magma supply to the segment centre along the Lucky Strike segment and that the igneous crust at the segment ends is formed primarily by magma eruption and/or diking. The upper crustal thickness has smaller variations in the across-axis direction to ~40 km distance, suggesting the current magmatic accretion mode could have been going for ~3.5 Myr. Beneath the central volcano, the crustal velocity is higher in the along axis direction above the LVA, suggesting seismic heterogeneity in the upper crust.
Dolomite formation in Jurassic carbonate platforms of Southern Germany
Authors: Müller Inigo A. , Peral Marion , Nuriel Perach , Claeys Philippe
Published: March 2024

During the Jurassic, southern Germany was covered by a shallow sea environment with active formation of carbonate platforms. As these platforms never experienced extreme pressure and temperature conditions due to deep burial or metamorphic overprint from nearby orogeny, we expect them to preserve relatively pristine formation fabrics. Still the top of these mainly limestone buildups are dolomitized and it is not well understood how this dolomitization proceeded.We study the origin of the dolomitization process of these Jurassic platforms with microscopic cathodoluminescence imaging to visualize different formation events, clumped isotope thermometry to derive the formation temperature and with the analysis of the elemental concentration distribution by µ-XRF we aim to obtain new insights on the formation process and the origin of the precipitation fluid.