bluuebunny/crossref_metadata_2025 huggingface dataset:
Sweet-spot mapping of the Kimmeridge Clay Formation in the UK North Sea for unconventional resource exploitation using a geostatistical modelling approach
Authors: Akinwumiju Akinniyi
Published: February 2023

With increasing global demand for oil and gas, the exploration of unconventional resource plays (shale oil and gas) continues to gain relevance. Such plays could be significant for maximising the production value in proven geological basins, allowing the exploration of a cleaner fossil fuel. Unconventional resources could play a part in the energy transition to lower-impact CO2 fuels while meeting current energy security needs.
For several decades, the UK North Sea has been a prolific oil and gas province, with numerous conventional oil and gas discoveries sourced predominantly by the Kimmeridge Clay Formation (KCF). In this study, we have used 3-D geostatistical modelling of the distribution of key geochemical and geomechanical properties for the KCF to investigate the potential of shale oil and gas plays within Quadrant 15 in the Outer Moray Firth region of the UK North Sea.
The utilized geochemical and geomechanical property logs were generated from sixteen selected drilled wells using machine learning and established property equations, while the top and base KCF structural depth maps used for modelling were created using grid- and isopach creation tools in Zetaware's Trinity software, an existing Base Cretaceous Unconformity (BCU) map of the UK North Sea and well top information from 58 wells within the study area.
The geostatistical property maps created for the KCF in Schlumberger’s Petrel software were then normalised and integrated to identity sweet spots for potential shale oil/gas exploitation, after the application of various cut-offs using standard industry thresholds for unconventional resources.
The modelling results suggest that the KCF show good potential for shale oil and gas exploitation within the central part of the Witch Ground Graben and limited areas of the Piper Shelf and Claymore-Tartan Ridge in the study area.  Further investigations on maturity, saturation and producibility will be conducted by 3-D basin modelling.
Adjoint-state traveltime tomography: A new modality of seismic imaging
Authors: Tong Ping , Chen Jing , Nagaso Masaru , Hao Shijie
Published: February 2023

We have witnessed a transit of seismic tomography from ray-based traveltime inversion to wave equation-based waveform inversion during the past two decades. As is widely known, full waveform inversion outperforms traveltime tomography in resolving velocity variations with dimensions comparable and smaller than the dominant wavelength. However, this may not be always true in real practice, mainly due to the presence of unknown data noise, the lack of accurate initial models for the iterative inversion process (including material properties and source mechanisms), and the high demand for computational resources. Further efforts are required to develop techniques for using full waveform contents in seismic imaging studies, especially for the use of high-frequency waveform data (>1 Hz on regional scales). We have attempted to use common-source double-difference traveltime data in wave equation-based adjoint tomography studies of subsurface structures beneath Northeast Japan and Alaska. Because of the high level of waveform similarity, reliable common-source double-difference traveltime data at neighboring seismic stations are measured via cross-correlation approach. Insightful results are obtained. However, it is still computationally prohibitive to model high-frequency data by solving 3-D wave equations, limiting the resolution of seismic images. We admit that there is still a long way to go for the possible wide application of high-frequency full waveform inversion.Traveltime is the most reliable information that can be extracted from raw seismological recordings.  We have developed a new modality of seismic imaging, called adjoint-state traveltime tomography, to unleash the full potential of traveltime in imaging subsurface structures. To avoid potential failure of ray tracing in 3D complex media, isotropic eikonal equation and anisotropic eikonal equations are used to model seismic traveltime field in heterogenous and anisotropic media, and the associated inverse problems are solved by the efficient adjoint state method. No ray tracing is required for the novel adjoint-state traveltime tomography method. Importantly, the sensitivities of traveltime-related objective functions to material parameters can be accurately measured even in complex media. We view adjoint-state traveltime tomography as a new framework for seismic tomography, as it naturally implements various body wave and surface wave tomographic inversions in a very similar way. Good performances of the adjoint-state traveltime tomography method will be reported via various case studies in regions with typically different tectonic settings. It is worth noting that an accompanying software package, TomoATT, is under development.
Data-Driven Cloud Cover Parameterizations
Authors: Grundner Arthur , Beucler Tom , Gentine Pierre , Giorgetta Marco A. , Iglesias-Suarez Fernando , Eyring Veronika
Published: February 2023

A promising approach to improve cloud parameterizations within climate models, and thus climate projections, is to train machine learning algorithms on storm-resolving model (SRM) output. The ICOsahedral Non-hydrostatic (ICON) modeling framework permits simulations ranging from numerical weather prediction to climate projections, making it an ideal target to develop data-driven parameterizations for sub-grid scale processes. Here, we systematically derive and evaluate the first data-driven cloud cover parameterizations with coarse-grained data based on ICON SRM simulations. These parameterizations range from simple analytic models and symbolic regression fits to neural networks (NNs), populating a performance x complexity plane. In most models, we enforce sparsity and discourage correlated features by sequentially selecting features based on the models' performance gains. Guided by a set of physical constraints, we use symbolic regression to find a novel equation to parameterize cloud cover. The equation represents a good compromise between performance and complexity, achieving the highest performance (R^2>0.9) for its complexity (13 trainable parameters). To model sub-grid scale cloud cover in its full complexity, we also develop three different types of NNs that differ in the degree of vertical locality they assume for diagnosing cloud cover from coarse-grained atmospheric state variables. Using the game-theory based interpretability library SHapley Additive exPlanations, we analyze our most non-local NN and identify an overemphasis on specific humidity and cloud ice as the reason why it cannot perfectly generalize from the global to the regional coarse-grained SRM data. The interpretability tool also helps visualize similarities and differences in feature importance between regionally and globally trained NNs, and reveals a local relationship between their cloud cover predictions and the thermodynamic environment. Our results show the potential of deep learning and symbolic regression to derive accurate yet interpretable cloud cover parameterizations from SRMs.
Approaching scientific research: creating bridges between secondary and higher education
Authors: Rego Balsa María Dolores
Published: February 2023

IES Plurilingüe de Valga is a secondary and high school in the autonomous community of Galicia. It is located in a rural environment where most of the students come from families with little or no contact with scientific research and the university world. That is why the students who pass their high school studies, at the time of entering the University (specifically, studies related to science) find a qualitative and quantitative leap that, in some cases, can lead them to abandon their academic life and go directly to the professional world. On the other hand, teachers from the scientific departments of the IES Plurilingüe de Valga have been observing that, every year, a small part of our students show a great scientific vocation together with skills and competencies compatible with studies and professional skills linked to different scientific disciplines. For all these reasons, IES Plurilingüe de Valga decided, in 2021, to apply to participation in a project called STEMbach (Baccalaureate of Excellence in Science, Technology, Engineering and Maths) whose main objectives are the following ones:Promoting the vocation of students towards scientific research and technology.Promoting a scientific, rigorous, orderly and critical mentality.Improving communication and expressive skills, especially those aimed at communication of scientific dissemination.Working in contexts that promote the full development of digital skills.Providing a close relationship between teachers and students.In order to achieve these objectives, the methodological strategies defined focus on the following actions:Students who enter this project will take an extracurricular subject related to the STEM field.Students must develop a scientific research project in collaboration with staff from any of the Galician Universities or researching centers. Its point of interest will be directly related to the STEM field. This action will allow students to work together with their high school teachers and also with university teachers, since the research project will be under the direction by university staff and carried out from the universities and research centers that directly collaborate in the STEMbach project.The students, always accompanied and tutored by institute teachers, will carry out training activities and academic visits to universities, entities or research organizations of recognized competence. They also will participate in conferences or projects of interest related to the scope of your research project.This program and its corresponding research project carried out by the students in collaboration with universities and research centers will last for the two high school years. At the end of their high school studies, students will obtain a special mention in their academic certification, which will reflect their participation in the STEMbach program. 
LiveCat : Development of an internal global real-time disaster loss estimation tool
Authors: Terrier Morgane
Published: February 2023

LiveCat is a disaster response tool operationally used at AXA to provide impact assessment at group level within 24 hours of a natural event occurrence. It covers several natural catastrophe perils at a global scale: earthquakes, floods, cyclones, European windstorms, etc. Providing a rapid loss estimation is essential for operational purposes such as claims management and communication to key stakeholders, to quickly deliver a response proportional to the event’s magnitude and likely impact.The overall methodology consists of (1) recovering or generating an alert according to a predefined threshold, (2) defining the event spatial characteristics and intensity, (3) identifying AXA customers and insured value within the event footprint, (4) modeling destruction rates and applying contractual terms (co-insurance, deductibles, limits, etc.), (5) estimating the claims number and associated losses and (6) generating the appropriate reporting and communication supports.LiveCat is directly integrated within the modelling ecosystem deployed at AXA and its internal R&D and expertise on natural hazards. Several internal AXA tools are supporting this impact assessment platform: a global insurance contract database gathering 40m+ insured risks (with detailed physical, financial and coverage descriptions), an internal hazard and financial modeling platform (running internal cat models at event scale and producing loss estimates per risk), and our internal geospatial solution for Nat Cat underwriting.Finally, LiveCat estimates are refined post-event and archived to consolidate the assessment of model backtesting and modelling methodology by matching actual collected claims and field feedback.
Changes in Arctic sea ice thickness distribution in Fram Strait over the last three decades, 1990 – 2019
Authors: Sumata Hiroshi , de Steur Laura , Divine Dmitry , Granskog Mats , Gerland Sebastian
Published: February 2023

Fram Strait is an ideal location to monitor long-term changes of sea ice properties in the central Arctic since the major fraction of ice export from the Arctic occurs here. The Fram Strait Arctic Outflow observatory has been monitoring sea ice and ocean outflows at ~79°N for the last three decades. We examined changes of monthly mean sea ice thickness distributions obtained from upward looking sonars deployed in the observatory. We found that the thickness distributions can be reasonably approximated by lognormal functions except for fractions of very thin ice classes. We fitted the observed distributions with lognormal functions and used three parameters of the functions (modal thickness, modal peak height and variance) to describe the long-term changes of the thickness distribution. We found that these parameters exhibit a concurrent change and indicate a shift of the Arctic sea ice regime. The first regime is represented by a thick and deformed ice pack, described by thicker modal thickness with a smaller and more broad modal peak with larger variance of the distribution. The second regime has a thinner and more uniform ice cover, represented by thinner modal thickness with more compact distribution around the mode and smaller fraction of deformed ice. We examine factors causing this shift and introduce a stochastic sea ice thickening model which can explain the change of the ice thickness distribution.
Potential of space-based TROPOMI observations for understanding the spatial and temporal variability of surface NO2 and its dependencies upon land use over south-western Europe
Authors: Petetin Hervé , Guevara Marc , Compernolle Steven , Bowdalo Dene , Bretonnière Pierre-Antoine , Enciso Santiago , Jorba Oriol , Lopez Franco , Soret Albert , Pérez García-Pando Carlos
Published: February 2023

This study presents a comprehensive analysis of the spatio-temporal variability of TROPOMI NO2 tropospheric columns (TrC-NO2) over the Iberian Peninsula over the period 2018-2021 (using the recently released PAL product to ensure consistency).A first exploration of the impact of cloud cover on the availability of TROPOMI TrC-NO2 observations indicates that data gaps range between 20-30% in summer to 55-70% in April and November, with substantial spatial differences between northern and southern and/or arid areas. The spatial distribution of TrC-NO2 highlights strong hotspots over urban areas (especially Madrid and Barcelona), with additional enhancements along international maritime routes and major highways. A reasonable correlation with surface NO2 mixing ratios is found, around 0.7-0.8 depending on the averaging time.The weekly and monthly variability of TrC-NO2 over the peninsula is then analyzed at the light of the urban cover fraction (taken from the Copernicus Land Monitoring Service). From least to most urbanized areas, the weekend reduction is found to range from -10 to -40%. A detailed analysis at the intra-agglomeration scale highlights that strongest weekend effects do not always peak in the center but sometimes in surrounding cities, which suggests a larger contribution of commuting to total NOx anthropogenic emissions. Similarly, the monthly profiles strongly change depending on the level of urbanization, from -40%/+26% in summer/winter in most urbanized areas, to -10%/+20% in least urbanized ones. Interestingly, the same analysis applied to cropland fraction highlight an enhancement in June-July that could be due to natural soil NO emissions that are known to peak during the warm season. Beyond some specific discrepancies, a generally good consistency is found between the variability of NO2 seen from space with TROPOMI and the one observed at the surface.Our study thus illustrates the potential of TROPOMI TrC-NO2 to provide a valuable complement to surface monitoring network, especially in agricultural and maritime areas where surface NO2 observations are missing but yet crucial for better understanding the impact of local NOx emissions, especially for the production of tropospheric ozone. Petetin, H., Guevara, M., Compernolle, S., Bowdalo, D., Bretonnière, P.-A., Enciso, S., Jorba, O., Lopez, F., Soret, A., and Pérez García-Pando, C.: Potential of TROPOMI for understanding spatio-temporal variations in surface NO2 and their dependencies upon land use over the Iberian Peninsula, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2022-1056, 2022.
Glacier mass balance and its climatic and non-climatic drivers in the Ladakh region during 2000-2021 from remote sensing data
Authors: Mandal Arindan , Vishwakarma Bramha Dutt , Angchuk Thupstan , Azam Mohd Farooq , Garg Purushottam Kumar , Soheb Mohd
Published: February 2023

The Ladakh region in the western Himalaya relies directly on snow-glacier-fed first order streams for domestic and agricultural needs of the population. Despite the significant contribution of glacier meltwater towards community livelihood and its vulnerability in a warmer climate, glaciers in the Ladakh region have not been studied comprehensively. Previous studies, mostly at a poor spatial (~90 m) and temporal (10-15 years) scales, focused only on geodetic glacier mass balance estimation, hence their controlling climatic drivers remain unknown. In this study, we estimate the geodetic mass balance of the glaciers of the Ladakh region, using multiple digital elevation models of 30 m resolution acquired between 2000 (Shuttle Radar Topography Mission; SRTM) and 2021 (Advanced Spaceborne Thermal Emission and Reflection Radiometer; ASTER). Due to the large aerial coverage, we divided the whole Ladakh region into two sub-regions namely the eastern and western Ladakh. The primary climatic drivers of glacier mass balances were examined using the long-term ERA5-Land reanalysis data, complemented by available in-situ meteorological data. The role of non-climatic (morphological) variables on glacier mass balances was also investigated in detail. The results reveal a negative glacier mass balance over the Ladakh region during the last two decades, with significant spatial variability. Glaciers in western Ladakh lost higher mass (-0.35 ± 0.07 to -0.37 ± 0.07 m w.e. a-1) compared to eastern Ladakh (-0.21 ± 0.07 to -0.33 ± 0.05 m w.e. a-1). Although the widespread mass loss in Ladakh is primarily caused by warming, the variations in spatial mass loss are primarily caused by the morphological settings of the glaciers. The eastern Ladakh glaciers are located at higher elevations and small sized, whereas western Ladakh glaciers are large sized and their tongues are situated at lower elevations (low-elevation-hypsometry), therefore, the impact of temperature is much higher in them, leading to higher mass loss. The non-climatic factors (morphological control) exhibit a dominant role than climatic factors in governing the glacier mass balances, particularly in the EL. The comparison between ASTER-based and the Ice, Cloud and land Elevation Satellite (ICESat)-2 laser altimetry-based mass balances shows a good agreement, reaffirming the robustness of regional mass balance estimates. Overall, glaciers of the Ladakh region are losing mass and the western Ladakh glaciers are potentially more susceptible to warming climate compared to the eastern Ladakh.
Pressure-Temperature-time-deformation (P-T-t-d) constraints on dome formation in the HTLP Pan-African Damara Belt, Namibia
Authors: Ormond Robyn , Lehmann Jérémie , Hasalová Pavlína , Elburg Marlina
Published: February 2023

The Pan-African Damara Belt in southern Africa is a trench-trench-trench triple junctions orogen that formed at 590-470 Ma during the Gondwana Supercontinent assembly. The Damara Belt records up to granulite facies HTLP metamorphism in the core, upper plate of the orogen. However, the cause of this metamorphism is not well understood. To tackle this problem, we focus on the ENE-WSW-trending Namibfontein-Vergenoeg (NV) migmatitic domes. We use P-T-t-d data to investigate the temporal relationships of deformation fabrics, metamorphism and melting.The NV domes formed through the superposition of four folding events. We use LA-(Q/MC)-ICP-MS U-Pb dating of monazite from structurally controlled granitoids and leucosomes to define the relative timing of the deformation phases. These include 1) an early phase of E-W shortening forming upright F1 folds and steep N-S-striking S1 deformation fabrics. D1 was active between ~559 and 530 Ma. 2) N-S shortening followed, forming dome-scale F2 anticlines with steep E-W-striking deformation fabrics at ~527 Ma. 3) Local inclined folding of S1 and S2 fabrics formed shallow NW-dipping S3 fabrics that was active before ~520 Ma. Lastly, 4) NE-SW shortening produced F4 folds and associated moderately NE-dipping S4 deformation fabrics at ~520-500 Ma.Rocks of the NV domes are metamorphosed to upper amphibolite facies. Melt (up to 10%) exists within and defines structures of all four deformation phases. All deformation fabrics show similar mineral assemblage; cordierite + sillimanite + biotite + K-feldspar + quartz + melt ± garnet and plagioclase with accessory amounts of apatite, monazite, zircon, ilmenite, and magnetite. Matrix consists of sillimanite, garnet, cordierite, biotite, quartz, k-feldspar, plagioclase, ± ilmenite, magnetite, monazite, zircon, and apatite. Two distinct garnet porphyroblasts occur, i) an earlier large (1-2 mm) poikiloblastic garnet (with sillimanite, biotite, and quartz inclusions) partly replaced by cordierite occurring mostly in D1 and D2 samples, and ii) smaller (up to 1 mm sized), peritectic garnet. Pseudosection modelling shows that rocks of the NV domes record HTLP conditions (740-760 °C, 4-4.5 kbar). The overgrowth of cordierite on early garnet in the presence of melt supports the HTLP conditions along the retrograde path.The rocks at the NV domes were deformed, in the presence of melt, four times over at least ~60 Ma under the same HTLP amphibolite facies conditions, during which granitic magmatism was prevalent. The absence of HP inclusions in porphyroblasts (either not preserved or never developed) and deformation structures supporting orogenic collapse, exclude decompression melting as a mechanism for crustal anatexis. Rather these data suggest the rocks continuously melted during crustal shortening, likely during the collisional phase of the orogen.
Continental mapping of groundwater-dependent ecosystems based on a high-resolution global groundwater model
Authors: Otoo Nicole G. , Sutanudjaja Edwin H. , van Vliet Michelle T.H. , Schipper Aafke M. , Bierkens Marc F.P.
Published: February 2023

The increase in global population has led to the expansion of water demands for agriculture, domestic and industrial use in areas with limited precipitation and surface water sources, increasing the dependency on groundwater resources. An increase in groundwater pumping combined with low recharge rates has increased the rate of groundwater depletion globally. An increase in water demand alongside a decrease in recharge rates can lead to reductions in groundwater levels and groundwater discharge, which may adversely affect groundwater-dependent ecosystems (GDEs) and their unique biodiversity and ecosystem services.Mapping and classifying groundwater-dependent ecosystems (GDEs) are key steps for understanding ecosystem-groundwater interactions as well as for optimizing the allocation of groundwater resources. However, manual mapping of GDEs is tedious, especially across large areas. Here, we aim to calibrate and apply a global groundwater model to map and classify GDEs across large extents. Our initial focus is on Australia, which is characterized by a large dependency of ecosystems on groundwater and for which GDE locations have been mapped across the continent, facilitating model calibration and validation.We use a recently developed high-resolution (30 arc-seconds) global groundwater model GLOBGM hydrology forced with recharge and surface water levels from the global hydrological model PCR-GLOBWB 2, to map three types of GDE, namely aquatic (streams, rivers and lakes), wetlands (fens, marshes and swamps) and terrestrial GDEs (phreatophytes). The model maps all ecosystems that depend on groundwater recharge in a steady state. To validate model output, it is compared to the Australian GDE atlas using a hit rate analysis and a 90% hit rate was found with aquatic GDEs. In the next steps, we seek to quantify the dependency level of these GDEs on groundwater recharge by running the groundwater model in a transient state globally. This assessment is useful for decision-makers in terms of groundwater allocation and biodiversity conservation within high-dependency GDE regions.
Digging up into windstorms aftermath: understanding the effect of harvesting systems on salvage logging wood residues spatial distribution
Authors: Udali Alberto , Cucchiaro Sara , Lingua Emanuele , Grigolato Stefano
Published: February 2023

Extreme disturbance events, such as climate change-driven ones, have increased their frequency, upsetting the ordinary management of forests, and impacting large areas with severe damage. As a consequence, when productive forests are hit, salvage logging operations represent the common way to recover part of the economic loose. However, salvage logging can lead to negative impacts in terms of soil erosion as well in terms of variation of soil carbon stock and nutrients. Commonly, in the European Alps, salvage logging operations in largely damaged forest areas can be referred generally to as two harvesting systems: i) Cut-to-Length (CTL) and ii) Full-Tree (FT) extraction systems.The application of the two harvesting systems can have a different effect on the type and quantity of logging residues and deadwood left on the forest ground, which in the short-medium term it can be reflected in terms of quantity and distribution of organic carbon and nutrients in the soil.To evaluate and gather more detailed information on the effects of forest operations, a valuable option is to rely on the use of precision forestry approaches, such as the use of remote sensing (RS) and Artificial Intelligence applications, for example, machine learning (ML). In the realm of forest operations, ML techniques and algorithms are the most used and can be fed with data directly extracted from the machines operating live on sites, and also with data retrieved through RS. Drone-borne data, for example, is now becoming the most used for its large potential and applicability, providing both large coverage and a high level of detail oversampled areas.The aim of this study is thus comparing two salvage logging areas and find any difference in terms of logging residue type, quantity, and spatial distribution according to the used harvesting system.Drone flights over two logging areas in the northeastern Alps to retrieve logging residues data were performed in 2022, the sites were windthrown in 2018 and harvested in 2021. A random forest model was built using RGB bands derived from the drone images, textural variables, and information from the surface model to classify elements in a clear-felled site. After the classification and noise removing operations, residues mass per hectare and distribution were estimated.Preliminary results will show the strengths and weaknesses of the method adopted in assessing the type of residues and their spatial distribution. Moreover, this application will highlight the different impacts of the two systems adopted in salvage logging operations with respect to residue type and quantity left on site.
Understanding and modeling meteorological drivers of the number of hospital admissions for malaria in South Africa
Authors: Blesic Suzana , Tosic Milica , Aleksandrov Neda , Kapwata Thandi , Maharaj Rajendra , Wright Caradee
Published: February 2023

We preformed statistical analysis of two sets of malaria incidence time series: of daily admissions from two large public hospitals in Limpopo Province in South Africa (records taken in the period 2002-2017), and of weekly epidemiological reports from five districts in the same province (for the period 2000-2020). We analysed these time series in relation to time series of temperature and rainfall ground or satellite data from the same geographical area.Firstly, we used wavelet transform (WT) cross-correlation analysis to monitor and characterize coincidences in daily changes of meteorological variables and variations in hospital admissions. All our daily admission records had global wavelet power spectra (WTS) of the power-law type, indicating that they are outputs of complex sets of causes acting on different time scales. We found that malaria in South Africa is a seasonal multivariate event, initiated by co-occurrence of heat and rainfall. We then proceeded to utilize obtained results for the analysis of the weekly cases data, using the WTS superposition of signals rule to discern WTS peaks that are time lags between the onset of combined meteorological drivers and hospital admissions for malaria. We presumed that all these peaks are characteristic times connected to the characteristic periods of development, distribution and survival of either mosquitos, as disease vectors, the pathogens they transmit, or the times needed for human incubation of the disease. Thus, we were able to propose a regression model for the number of admissions (for malaria) cases, and to provide critical values of temperature and rainfall for the initiation of the disease spread.Finally, using the developed model we investigated how future changes of meteorological variables and their combination can affect malaria dynamics, and thus provide information that can be of use for public health preparedness.
Triple-funneling of trees? Intra-canopy preferential flow of water and elements induced by tree canopies
Authors: Michalzik Beate , Tischer Alexander , Zerhusen Patrick , Richter Ronny , Engelmann Rolf A. , Küsel Kirsten , Wirth Christian , Herrmann Martina
Published: February 2023

Trees affect the direction and distribution of crucial components of the hydrological cycle, which were mostly described by measurements on the quantity of precipitation, stemflow and throughfall (TF) collected underneath the canopy. However, due to poor accessibility of tree canopies, our knowledge on hydrological processes within canopies is limited. We propose that canopy structure shapes the spatial distribution of incoming rainfall (RF) within the canopy as well as the intra-canopy TF composition. The Leipzig Canopy Crane facility allows to (i) determine water fluxes from above the canopies (RF) and with TF at top, mid and bottom position within the canopy of three tree species – Quercus robur, Fraxinus excelsior, and Tilia cordata, and (ii) to determine the transport of dissolved and particulate organic carbon and nitrogen with TF. In total, 81 TF collectors were set up every month for a two-weeks-period from March to October 2021.We found amplified water fluxes in TF collectors at top and mid canopy positions compared to incoming RF fluxes, while TF volumes at the bottom decreased. Dimensions of change appear related to RF amount and tree species. Moreover, stability plot analysis indicated that spatial “hot spots” of water fluxes within canopies were temporally persistent.Our results raise the question whether the concept of a “double-funneling of trees” introduced by Johnson and Lehmann (2006) needs to be extended to a “triple-funneling” approach involving the intra-canopy preferential flow of water and elements occurring in upper to mid canopy positions. Canopy spots with higher water and matter accumulation will alter the chemical, biological, and hydrological heterogeneity in canopy habitat structures below, with strong implications for canopy-associated microbial communities and epiphytes and ecosystem functions.
Realistic interseismic strain rate uncertainties from inherently sparse GNSS-networks
Authors: Broerse Taco , D'Acquisto Mario , Govers Rob , Marsman Celine , Amiri-Simkooei Alireza
Published: February 2023

Before geodetically derived strain and rotation rates can be robustly compared to geological or seismological observations, we need reliable strain rate uncertainties. Various methods exist to compute strain rates from GNSS-derived interseismic velocities, but a realistic representation of interpolation uncertainties has remained a challenge. The main problem is that commonly used deterministic interpolation methods do not account for uncertainty resulting from the absence of information in between observation sites. We apply stochastic interpolation by means of ordinary kriging to propagate errors both from discontinuous data coverage as well as from observation uncertainties to our strain rate estimates. However, interseismic horizontal surface velocities in tectonically active regions are spatially highly non-stationary, with high spatial variability around active faults and lower velocity variability in tectonically more stable regions. This requires an extension of traditional ordinary kriging approaches. For interpolation uncertainties that reflect the local variability and spatial correlation of the observed surface velocities, we apply a novel method that incorporates the spatially variable statistics of the underlying data. We estimate realistic uncertainties and covariances of the interpolated velocity field. For regions with a high spatial velocity variability, we find a large increase in uncertainty with increasing distance from observation sites, while in areas with little spatial variability, we estimate a small increase in uncertainty with distance. Subsequently, we propagate interpolated velocity covariance to strain rate uncertainties, such that we can assess the statistical significance of the interpolated strain rate field. Applied to a number of actively deforming regions, including the Pacific coast of North America and Japan, we show to what degree we can robustly determine strain rates based on available GNSS-derived velocities. Realistic uncertainties assist the community to better discriminate continuous or localized deformation on active faults from the available geodetic data. 

 

 
Exploring the impact of satellite products on the calibration of the conceptual hydrological model
Authors: Aleksić Milica , Kubáň Martin , Paulíková Lynda , Hlavčová Kamila , Szolgay Ján
Published: February 2023

The observations made from satellite technology enable more and more scientific communities to test and rely on this kind of product. Moreover, data acquired from satellite products is of great use regarding conceptual hydrological modeling. This study represents the process of testing the advanced scatterometer (ASCAT) remote sensing product-ASCAT SWI. In regions with little or no data, soil moisture products have significant value. They represent the relationship between surface and root zone soil moisture as a function of time. SWI represents the soil moisture content equal to a soil depth of 1 meter represented in percentage (%), with a minimum of 0% and a maximum value of soil moisture at 100% of soil capacity. In this study, the tested data in focus are soil moisture data with changing values of modeled water infiltration into the different soil layers (T). In addition to these data, the hydrometeorological data are used for hydrological modeling. These are data from water gauge stations such as runoff values (Q), precipitation (P), air temperature (T), and potential evapotranspiration (PET). All the data used in the hydrological model represent the time series from 01.01.2007 to 31.12.2019. The spatial resolution of the datasets is 500x500 meters, and the temporal resolution is one day. Calibration was performed using the lumped hydrological model developed at Technical University in Vienna-TUWdual. Areas of interest in modeling are selected catchments in Slovakia with various land use and height above sea level. Another aim of this study is to test the correlation between the measured soil moisture and the modeled one using the TUWdual model. The expected outcome of the study should point out the catchment areas that would benefit more from the additional data on satellite soil moisture in Slovakia. Acknowledgment: This study was supported by a Ph.D. student project HYDRODIAĽ.
The Arctic-Siberian Plain warming drives the heat waves in East Asia.
Authors: Kim Jeong-Hun , Kim Seong-Joong , Kim Joo-Hong , Hayashi Michiya , Kim Maeng-Ki
Published: February 2023

Generally, it is well known that the East Asian heatwaves are strongly affected by the Pacific-Japan pattern and circum-global teleconnection pattern. However, recent studies suggest that various teleconnection patterns also can contribute to the East Asian heat waves (e.g., Scandinavian pattern, Arctic Oscillation, El Nino-Southern Oscillation, etc.). However, the teleconnection between the Arctic-Siberian Plain (ASP) warming and East Asian heat waves has been unexplored. This study investigates the teleconnection mechanism between East Asian heatwaves and the warming over the ASP for the last 42 years (1979-2020). The results show that the enhanced surface radiative heating by the anticyclonic anomalies over the ASP region increases the air temperature and surface evaporation, amplifying the thermal high pressure via positive water vapor feedback. The Rossby wave, amplified by land-atmosphere interaction in the ASP, propagates to East Asia through the upper troposphere, causing favorable atmospheric patterns for the occurrence of the East Asian heatwaves.
Vertical distribution of black carbon and its mixing state in urban boundary layer in summer
Authors: Liu Hang , Pan Xiaole , Sun Yele , Wang Zifa
Published: February 2023

The vertical distribution of black carbon (BC) as well as its mixing state is of great concern due to BC’s strong regional climatic and environmental effects. In this study, vertical measurements were conducted through a moveable container based on a meteorology tower in an urban area. A total of 112 vertical profiles (0-240 m), including the concentrations of BC, O3, NOx and the optical properties of aerosols, were obtained. Based on BC concentration, the vertical profiles could be classified into four categories: uniform, gradual decrease, sharp decrease, and sudden increase. The uniform type indicates strong vertical mixing with similar pollutant concentrations along the vertical direction. The gradual/sharp decrease types indicate stable vertical conditions with higher pollutant concentrations on the ground and lower concentrations at higher altitudes. Due to the strong radiation in summer, the vertical profiles exhibited a clear diurnal variation in which ~80% of profiles were uniform during the daytime and ~40%-90% of profiles were gradual/sharp decrease types at night. O3 is an exception, and its concentration generally increases with height even under strong vertical mixing conditions. The size distribution of BC core varied slightly along the vertical direction, and the coating thickness of BC increased with height under stable conditions. However, the vertical variation in BC concentration is much more significant than BC coating thickness and plays a more critical role in the determination of BC absorption ability vertical distribution. In addition, O3 and Dp/Dc occasionally increased during 6:00-8:00 but remained stable during 8:00-10:00. Vertical mixing and transportation from upper heights, such as the residual layer, could significantly influence the pollutant properties on the surface during early mornings. This study exhibits a continuous vertical picture of BC and its mixing state in urban areas, which would be helpful for understanding BC’s regional environmental effect.
Alpha-Beta quartz transition in the lower continental crust: perspective from diffraction and acoustic data at high P-T conditions
Authors: Mingardi Giulia , Gasc Julien , Moarefvand Arefeh , Crichton Wilson A. , Schubnel Alexandre
Published: February 2023

Quartz is a common constituent of most rocks in the Earth continental crust and it undergoes the α-β transition at depths controlled by the geotherm. Despite the α-β quartz transition representing one of the most well-known and largely studied phase transitions in geological sciences, only few works report the behaviour of this transformation at high pressure (i.e. in the relevant conditions of the deep crust). Hence, it is important to investigate this transformation through an experimental approach at lower-crust pressure and temperature (P-T) conditions.In this study, we performed deformation experiments at high P-T conditions on novaculite (quartzite) samples using a Griggs apparatus equipped with acoustics and a multi-anvil press at the European Synchrotron Radiation Facility (ESRF, beamline ID06). Experiments were performed at 1-3 GPa and up to 1000°C.Measurements in the Griggs apparatus indicate that the expected P-wave velocity increase in the β-field is not observed at high pressure. Diffraction data from ESRF show that the transition becomes smoother at high pressure and results in a smaller crystal lattice change than it does at low pressure, consistently with the P-wave velocity measurements in the Griggs apparatus.In addition, on the temperature-up path we are able to observe the expected negative thermal expansion of β-quartz but, interestingly, this behaviour is not visible on the cooling path. As a possible explanation, we suggest a competing effect of stress and temperature on the crystal lattice parameters. Moreover, at the transition, in a short temperature range, the intensity of quartz diffraction peaks decreases significantly. Acoustic measurements seem to indicate that this could be also related to a transient increase in attenuation. Further experiments will be performed at the ESRF coupling X-ray diffraction and acoustic measurements to assess the relationship between crystal structure and Vp changes.Our results question the interpretation of seismic contrasts in the deep crust as due to the α-β quartz transition. However the existence of a high attenuation region might reflect the presence of this transformation.
Effect of drainage intensity on lateral carbon fluxes in forested peatlands
Authors: Laurén Annamari , Kiuru Petri , Könönen Mari , Peltomaa Elina , Pumpanen Jukka , Ojala Anne , Hasselquist Eliza , Laudon Hjalmar , Ostonen Ivika , Renou-Wilson Florence , Petty Aaron , Palviainen Marjo
Published: February 2023

Planning of peatland management under contrasting economic and environmental targets requires application of ecosystem models that can account for complex interactions and feedbacks between biogeochemical, hydrological and forest-related processes. Here we present a further developed version of Peatland simulator SUSI (Lauren et al. 2021) that calculates formation, transport and biodegradation of dissolved organic carbon (DOC). We tested the new model structure against laboratory incubation results containing peat columns from Finland, Estonia, Sweden and Ireland. The drainage strategy (distance between ditches and ditch depth) is considerably different in all these countries: In Finland the ditch network forms a dense fish-bone pattern with an average ditch distance of 40 m, in Estonia the ditch distance is longer but the ditches are arranged to square blocks, in Sweden the network is often irregular, and in Ireland shallow ditches are spaced densely. Then we applied SUSI and assessed the impacts of changing ditch depth and distance on stand and soil C balance, lateral C flux and forest growth. We found that DOC export originated mainly from the close proximity of the ditches because the rate of decomposition is highest and the transport time is shortest. Further from the ditches, water residence time can be several months or even longer enabling biodegradation of a large part of DOC during the transport. The results revealed that even small slopes had a remarkable impact on WT, residence time and DOC export; and that the effect of the slope could exceed that of drainage dimensions per se. Overall results indicated that drainage strategy in Finland was particularly sensitive to changes in ditch depth and distance. In contrast, changes in irregular, sparse ditch network in Sweden caused only minor effects on forest growth, C balance and lateral C fluxes. 
Magnetic analysis of individual iron oxide grains; application of Micromagnetic Tomography to a natural sample.
Authors: Kosters Martha , de Boer Rosa , Out Frenk , Cortes Ortuno David , Volk Michael , de Groot Lennart V.
Published: February 2023

The magnetic information stored in volcanic rocks is a valuable archive of the history of the behavior of the Earth’s magnetic field. Micromagnetic Tomography (MMT) allows to determine magnetic moments of individual iron-oxide grains in rocks. Theoretically this enables us to separate contributions from non-ideal recorders and ideal recorders, overcoming the difficulties arising from bulk measurements. Here we present results from two sister specimens from the 1907-flow from Hawaii’s Kilauea volcano to which MMT was applied. One specimen was imaged both by the Quantum Diamond Microscope in Harvard and by the MicroCT scanner Nanoscope–S in Delft, producing magnetic moments of 1,646 individual grains. The sister sample underwent stepwise AF-demagnetization: a step toward classic paleomagnetic analysis, from which we present (preliminary) results. In MMT, individual grains are allocated a magnetization through a least-squares inversion. For the first sample, we produced more than one magnetization for each grain, because each grain was present in multiple unique inversion ‘tiles’ (smaller sub-areas  due to computational constraints). This enabled a statistical analysis of the (robustness of) results, presented here. For the second sample (preliminary) demagnetization results per grain are presented. We also present results of an investigation into a parameter for selecting grains that can be reliably resolved from the statistical analysis. For both samples only relatively large iron-oxide grains (diameter > 1.5 -  2 µm) were resolved, as the resolution of the MicroCT was limited. However, any analysis of magnetism at grain level is a step in understanding how magnetizations are stored in individual grains, and is of importance for those specimens that only contain large iron-oxides.
Regional Persistent Extreme Precipitation Events over Southwest China under Different Low-Latitude Intraseasonal Oscillations during Rainy Season
Authors: Nie Yanbo
Published: February 2023

Southwest China (SWC) is vulnerable to disasters caused by extreme precipitation. This study investigates the mechanisms of low-latitude intraseasonal oscillations affecting regional persistent extreme precipitation events (RPEPEs) over SWC during rainy seasons. Most of the RPEPEs over SWC are dominated by 7–20-day variability. The RPEPEs over SWC are preconditioned by two different types of 7–20-day Rossby waves with almost opposite phases over the western North Pacific (WNP). The two types of 7–20-day Rossby waves have direct (indirect) effects on Type 1 (2) RPEPEs, respectively. For Type 1, a coupled 7–20-day low-level anticyclone and suppressed convection originating from the tropical WNP propagate northwestward and cover the region from the South China Sea (SCS) to the Bay of Bengal before the RPEPEs. The anticyclone triggers ascending motion over SWC and transports more moisture to SWC, favoring the SWC RPEPEs. Before the Type 2 RPEPEs, a coupled 7–20-day low-level cyclone and enhanced convection propagates from the tropical WNP to the SCS. The enhanced convection over the SCS leads to the westward extension of the western Pacific subtropical high (WPSH) and the eastward shift of the South Asian high (SAH). The variations in the WPSH and the SAH directly cause SWC RPEPEs by inducing ascending motion and transporting moisture. The mechanisms for Type 2 RPEPEs tend to work under the background with a strong WPSH. Using a Lagrangian model, we found that both the 7–20-day oscillations and their background atmospheric circulations result in significant differences in moisture sources for the two types of RPEPEs. These findings benefit a better understanding of SWC extreme precipitation events.