bluuebunny/crossref_metadata_2025 huggingface dataset:
Hourly model simulation to improve the estimation of extreme floods in small catchments in Western Germany
Authors: Han Li , Guse Björn , Nguyen Dung , Rakovec Oldrich , Guan Xiaoxiang , Vorogushyn Sergiy , Samaniego Luis , Merz Bruno
Published: February 2023

The July 2021 flood in Western Germany is one of the most severe flood events in small-scale catchments during the past decades. It has led to life loss and severe damage in the Ahr, Erft, and Rur basins. The BMBF-funded joint project KAHR (https://hochwasser-kahr.de) deals with the effects of this flood and develops scientific knowledge to assist the reconstruction process. To analyze past floods and develop future flood management strategies, there is a need for small-scale flood modeling with finer spatial-temporal resolution in this area. Based on the derived simulated floods, we can investigate the spatiotemporal patterns of extreme weather and associated meteorological and hydrological conditions that could lead to similar or more significant flood events.This study uses the mesoscale hydrological model mHM at hourly resolution for three small catchments Ahr, Erft, and Rur. This is one of the first applications of mHM forced with hourly meteorological forcing data and should enable more accurate processes and representation of such extreme floods. In a further step, a regional weather generator and a disaggregation procedure are applied to generate 10,000 years of synthetic hourly meteorological data for the Ahr, Erft, and Rur catchments. These data are used to create long time series of discharge with the calibrated mHM model. This enables the investigation of extreme floods and the assessment of flood risk under future climate conditions.
Linking fluid flow in a shear zone to the surrounding bulk with poroelastic boundary integral solutions
Authors: Heimisson Elías Rafn , Wang Yuhan
Published: February 2023

A central problem in earthquake physics and fault mechanics is understanding the coupling of fluid and solid phases during fault slip. This coupling is mostly treated as a one-way coupled problem where the pore pressure is imposed as a perturbation in effective normal stress. However, more recent work indicates that the two-way coupling of a porous fluid-filled bulk and pressure changes in the shear zone significantly alters rupture properties. Further, a qualitative analysis of this problem in a poroelastic medium reveals that pore pressure inside an mm to micron thick frictional shear zone cannot be constant as slip dynamically evolves. This analysis calls into question the practice of imposing pore pressure as a perturbation to effective normal stress at an infinitesimal interface and raises fundamental questions regarding the interpretation of the effective stress principle. Here we explore two ways to couple shear zone processes on a mm-micron scale to the meter-kilometer scale bulk processes. Efficient coupling across these scales is achieved with a spectral boundary integral representation of a poroelastic bulk. Furthermore, the boundary integral representation reduces the dimension of the computational problem that needs to be discretized by one. In other words, it allows us to simulate 3D physics by only discretizing in 2D. We develop boundary integral solutions in 2D and 3D medium that are appropriate for modeling shear zone that can undergo pressure changes, expansion/contraction, and shear localization. First, we explore an efficient approach where shear zone properties are averaged and dimensionally reduced, thus with finite shear zone effects built into the boundary conditions of the bulk in 2D and 3D. Second, we show how a shear zone can be explicitly modeled, but the coupling to the surrounding bulk is done with a boundary integral representation. Thus, offering relatively efficient modeling of processes such as shear localization, dilatancy, thermal pressurization, and how such processes interact with the bulk. We suggest that such use of boundary integrals may be applied more generally to achieve two-way fluid-solid coupling at lower computation expense.
Geography in Ukraine, at school, in the heart
Authors: Kitchenko Valentina
Published: February 2023

The importance of geographical science in the life of each of us is difficult to overestimate. She is everywhere. Every child is a discoverer of this beautiful world from birth. Our task as teachers is to direct, suggest, give the right guidelines.The study of the geography subject starts from the 5th grade and continues until the 11th. Not only children, but also adults have reconsidered the importance of knowledge about their region. This did not happen due to pleasant events. But the Ukrainian people wholeheartedly not only relearn, but also understand the laws of geography.Our school is located in a picturesque corner of Ukraine, in the Poltava region. A river flows on the territory of the institution, a forest is nearby, and there are many flowers in the spring. Physical geography is studied by seeing, feeling nature and beauty.Every year, in addition to geography lessons, children participate in competitions, writing scientific papers on current topics. For example, the student's recent topic was "Gastronomic tourism in the Poltava region". And it is not surprising. The region has its own culinary traditions, it is the unique code of the nation.Today, geography lessons, like all other classes at our institution, are held online. This requires constant improvement and a modern approach to teaching the subject.It is nice to note that after finishing school, children make the choice to connect their future profession with geography. These are geography teachers, tourism workers, and surveyors.I also graduated from Anton Makarenko Poltava Lyceum and chose the profession of geography teacher.To update the content of geography teaching, the institution cooperates with the university where geography teachers are trained. At one time, I also graduated from Poltava National Pedagogical University named after Korolenko. It is nice to continue to receive inspiration for work and new modern geographical knowledge.It is the students who make us go forward and improve. A geography lesson should always be interesting, open children's minds to the understanding and beauty of this world.The opportunity to participate in the GIFT 2023 Workshop on «The key role of geosciences for the global challenge of sustainable development: the Agenda 2030» is a difficult challenge for me, but a great opportunity at the same time.
Interactions between the dual-verging thrust faults in eastern Taiwan revealed by the 2022 Chihshang earthquake sequence and centennial historical seismicity
Authors: Tang Chi-Hsien , Lin Yunung Nina , Tung Hsin , Wang Yu , Lee Shiann-Jong , Hsu Ya-Ju , Shyu J. Bruce H. , Kuo Yu-Ting , Chen Horng-Yue
Published: February 2023

Nearby faults interact with each other through stress fluctuation incurred by seismic rupture, aseismic slip, and viscoelastic flow in the lithosphere. Understanding fault interactions and their temporal variation under different geometry are critical to regional seismic hazard and risk assessments. However, the complex interplay between adjacent faults is often unclear due to insufficient observations of large earthquakes with prolonged recurrence intervals. The 2022 Chihshang earthquake sequence in eastern Taiwan provides unprecedented insights into the interaction between two head-to-head thrust faults during and after a major earthquake. The Chihshang sequence was initiated by an Mw 6.5 foreshock on 17 September, followed by an Mw 7.0 mainshock 7 km to the north and 17 hours later. Based on the coseismic displacements constrained by field survey, optical satellite images, interferometric synthetic aperture radar (InSAR) data, and a dense network of Global Navigation Satellite System (GNSS) measurements, we map the major coseismic rupture on the east-verging Central Range fault (CRF), and the secondary induced slip on the west-verging Longitudinal Valley fault (LVF). The induced slip on the LVF accounts for 9-15% of the total moment release (Mw 7.1). Before the Chihshang earthquake sequence, the seismic hazard along the CRF was much overlooked due to the high seismic activity of the LVF. The 2022 Chihshang earthquake sequence demonstrates for the first time that the CRF is capable of generating earthquakes of Mw 7. The early afterslip primarily took place on the downdip extension of the CRF at great depth, indicating a contribution of ductile deformation there. Incorporating historical earthquake records over the past 120 years, we demonstrate that a rupture on the CRF or LVF reduces the stress level on the other, causing periods of seismic quiescence and an out-of-phase moment release pattern over time between the two faults. These results not only illuminate the fault geometry at the plate suture zone of eastern Taiwan, but also revise the conventional view of the nearby fault interaction. Integrating geometric complexity and fault slip history among adjacent faults in future modeling is essential for assessing realistic seismic hazards in similar structural settings.
Towards Circular Economy by Using Green Concrete in the Egyptian Building Sector
Authors: Marey Heba , Kozma Gábor , Szabó György
Published: February 2023

Concrete is considered the most anthropogenic material used in the construction sector worldwide. It is associated with consuming massive amounts of energy and the depletion of natural resources, based on the increasing Egyptian urban expansion by establishing new cities to face the population growth challenges and achieve the national development strategy. The importance of applying the Circular Economy (CE) for concrete materials in the building sector became a robust key for reducing conventional concrete (CC) materials and addressing the building materials' future challenges. This study investigates the benefits of Green Concrete (GC) materials and their potential for supporting the principles of achieving circularity for concrete materials in the Egyptian building sector. Furthermore, develop a conceptual framework for using GC from the building scale perspective in two new Egyptian cities. The study attempts to answer how GC materials help achieve a circular economy and the potential benefits of integrating different CE strategies for using GC in the Egyptian building sector. The evidence-based solutions (EBS) methodology was used for collecting and analyzing data for assessing the environmental impacts based on reducing the natural resources consumption, recycling, and reusing waste products in the Egyptian building sector. Case studies are used to provide in-depth insights into the practicalities of GC. Applying the before-and-after (BAA) technique for two building models highlights the challenges and opportunities for substituting CC with GC to assess the interactive factors for achieving CE and applying sustainability. The results showed valuable insights into the potential for using GC to support the CE and have a strong ability to reduce natural resources consumption and construction waste stream, which leads to close the loop and achieving circularity in the Egyptian building sector, and recommended that Design for Recycling (DfR) strategy is the most need for improving the using of GC in the building sectors.Keywords, Green Concrete, Circular Economy, Evidence-based Solutions, Egyptian building sector
Assessing Rainfall Kinetic Energy – Rain Intensity Relationship through Field Observations
Authors: Testik Firat , Saha Rupayan
Published: February 2023

This study evaluates efficacy of rainfall kinetic energy (KE) and rain intensity (I) relationship through field observations under different wind conditions.  KE-I relationship is critical for various applications.  For example, rain-induced soil erosion, for which KE is an important indicator of potential rain splash erosion, may cause severe environmental and agricultural issues during, especially, heavy rainfall events.  Fertilizers removed from the soil due to rain-induced erosion pollute waterbodies, silt up the basin, and reduce basin capacity that may trigger flooding.  In this study, the KE-I relationship was investigated using raindrop size and fall speed measurements by a disdrometer and wind speed measurements by a 3D Ultrasonic anemometer.  Rainfall events considered in this study were selected from a 3-year long field campaign conducted at our outdoor rainfall laboratory located on the West campus of the University of Texas at San Antonio, Texas, USA.  Using these measurements, different KE-I relationships reported in the literature were evaluated through statistical analyses.  A new parameterization for the KE-I relationship was also developed based upon our field observations, and wind-induced effects on KE-I relationship are discussed.  The results of this investigation with potential implications will be discussed in this presentation.  This material is based upon work supported by the National Science Foundation under Grants No. AGS-1741250.
The Sugar-To-Flower Shallow Cumulus Transition Under the Influences of Diel Cycle and Free-Tropospheric Mineral Dust
Authors: Narenpitak Pornampai , Kazil Jan , Yamaguchi Takanobu , Quinn Patricia , Feingold Graham
Published: February 2023

A shallow cumulus cloud transition from a sugar to flower type of organization occurred under a layer of mineral dust on 2nd February 2020, during the multinational Atlantic Tradewind Ocean-Atmosphere Mesoscale Interaction Campaign (ATOMIC) and the Elucidating the Role of Clouds-Circulation Coupling in Climate (EUREC4A) campaigns. Lagrangian large eddy simulations following an airmass trajectory along the tradewinds are used to explore radiative impacts of the diel cycle and mineral dust on the sugar-to-flower (S2F) cloud transition. The large-scale meteorological forcing is derived from the ECMWF Reanalysis 5th Generation (ERA5) and based on aerosol measurements from the U.S. Ronald H. Brown Research Vessel and the French ATR-42 Research Aircraft during the field campaigns. A 12-hr delay in the diel cycle accelerates the S2F transition at night, leading to more cloud liquid water and precipitation. The aggregated clouds generate more and stronger cold pools, which alter the original mechanism responsible for the organization. Although there is still mesoscale moisture convergence in the cloud layer, the near-surface divergence associated with cold pools transports the subcloud moisture to the drier surrounding regions. New convection forms along the cold-pool edges, generating new flower clouds. The modulation of the surface radiative budget by free-tropospheric mineral dust poses a less dramatic effect on the S2F transition. Mineral dust releases longwave radiation, reducing the cloud amount at night, and absorbs shortwave radiation during the day, cooling the boundary-layer temperature and increasing the overall cloud amount. Cloud-top radiative heating because of more clouds strengthens the mesoscale organization, enlarging the aggregate areas, and increasing the cloud amount further.
The hidden activity of volcanoes: magma degassing events
Authors: Chiodini Giovanni , Bini Giulio , Caliro Stefano
Published: February 2023

The ratio between fumarole gas species of predominant magmatic origin (i.e., CO2, He) and CH4, which is typically produced in the hydrothermal environment, is a powerful indicator of the upflow of magmatic fluids towards the surface. The analysis of time series of fumarolic composition from different dormant volcanoes (e.g., Campi Flegrei, Vesuvius, Vulcano, Panarea, Nisyros, Mammoth Mt) reveals similar anomalous peaks of the CO2/H2O, CO2/CH4, and He/CH4 ratio during unrests, suggesting recurrent events of magma degassing. The sudden upflow of deep magmatic fluids causes pressure buildup and heating of the hydrothermal systems, earthquakes and ground deformations, which precede the fumarole gas compositional anomalies. These anomalies, once normalized to the time and to the amplitude of the curve, show the same shape: a rapid increase in the geochemical indicator followed by an exponential decrease.An intriguing consideration based on these examples (almost all the volcanoes for which a long time series of fumarolic compositions are available) is that episodes of magma degassing probably reflect the normal background activity of volcanoes, making the interpretation of volcanic unrests challenging. Concurrently with magma degassing events, a significant increase in the CO2 degassing process was either measured or qualitatively observed in these systems. A better knowledge of these degassing episodes is needed to improve our understanding of the volcanic behavior and to better constrain the release of CO2 from quiescent volcanoes.  
Unification of height systems using chronometric geodesy – A more realistic scenario
Authors: Vincent Asha , Mueller Juergen , Shabanloui Akbar
Published: February 2023

The high accuracy of optical atomic clocks can be well utilized in geodetic applications. When clocks are placed on the ground, their position and mass distribution decide their ticking rates due to the relativistic phenomena of gravitational redshift. Hence, the fractional frequency difference between two terrestrial atomic clocks provides the gravitational potential difference or the corresponding height difference between them. This novel method of relative height measurement can be used in estimating the discrepancies between local and regional height systems to an accuracy of 1 cm with high-performance clocks achieving a fractional frequency uncertainty of about 10-18. In our simulation, more realistic errors in the local height values are assumed by considering different scenarios like systematic tilts that can accumulate with the distance from the tide gauges, effects due to the elevation of the leveling points, the presence of noisy leveling lines, etc. As a test case, a known a priori height system was split into local systems affected by various errors, and the reunification was carried out using simulated clock measurements. External tidal effects at each clock site have also been considered for a more realistic comparison. The accuracy in the estimation of specific height errors in the involved systems highly depends upon the number of clocks and their spatial distribution in each local system and hence, they have to be optimized in each test case. The error accumulation during height measurements over long distances does not play a role for clock measurements, in contrast to classical spirit leveling. Thus, chronometric leveling proved to be a promising technique that can complement and partly replace the traditional methods in geodesy.
analogue modelling of multiple compressive phases deforming and extended margin
Authors: badraoui oumaima , Del Ventisette Chiara , Maestrelli Daniele , Zaghloul Mohamed Najib , Sani Federico
Published: February 2023

Earlier extended continental margins are frequently involved into late compressive deformation during mountain building (i.e. orogenesis). This process gives rise to positive inversion of previous extensional faults, but these structures may also play different roles during late compressive phases, interacting in various ways with inherited structures from older tectonic stages.Moreover, different orientation of compression direction related to different phases affecting extended continental margins may give rise to complex structural settings whose evolution is often difficult to reconstruct. To address this problem, we performed an analogue model experimental series aiming at extending a continental margin and then imposing on the same margin differently oriented compressive phases. Models were quantitatively analyzed through particle image velocimetry (PIV) to highlight fault interaction, and by using Digital Elevation Models reconstructed with Structure from Motion (SfM) techniques. Our results show that well developed and favorably oriented normal fault systems drive the location of successive compressive structure, often through inversion processes, but they also condition the final geometrical setting without inversion. Moreover, an important role is also played by the orientation of the direction of compression (obliquity angle a varied from 0° to 90°), which gives rise to different structural patterns when is superimposed to extensional structures as a first compressive phase or is superimposed to already formed compressive structure as second compressive phase. The resultant complex structural patterns show differently oriented structures cutting each other even at high angles, a feature often seen in nature. Therefore, these experiments may be applied to a variety of natural cases, helping to decipher geological evolution of the analyzed areas basing on the geometrical relationships among structures.
Choosing the appropriate spatial scale for flash flood risk assessments in Mediterranean mountain watersheds
Authors: Kougkoulos Ioannis , Xie Yuke , Merad Myriam , Apostolaki Stella , Cook Simon J.
Published: February 2023

In the Mediterranean, substantial economic losses are incurred each year due to flash floods; their rapid onset and unpredictability is a significant challenge for regional and national government responses. To help communities foresee and prevent some flood-related impacts, researchers often provide flood risk prevention models that rank different sub-basins within a single watershed from highest to lowest risk. Nevertheless, in countries within the EU, decisions to act against flooding (and other disasters, such as wildfires and storms) are often taken after interaction with the concerned municipality or regional government. We argue here that attempting to act across multiple scales simultaneously adds confusion and limits the capacity for effective disaster operations management. In order to address those complexities and suggest an ideal scale for future modelling of flash flooding in similar areas we focus on Storm Alex which formed on the 30th of September and dissipated on the 3rd of October 2020 producing the worst rainfall in 120 years in the French Provence-Alpes-Côte d'Azur (PACA) region, causing 16 fatalities. The most heavily impacted community was that of Saint-Martin de Vésubie in the Vésubie river watershed. Past research on this event has focused mainly on a) describing how the event unfolded and b) illustrating issues in French Flood Risk Governance (FRG) providing useful data surrounding the event but neglecting the decision-making issue of watershed vs. municipality scales mentioned above. We use Multi-Criteria Decision Analysis (MCDA) that draws information from satellite imagery, GIS and web resources to create a desk-based flash flood risk assessment and then use it to analyze the impacted area in two different scales; a) the watershed scale, dividing the Vésubie watershed into 10 sub-basins following terrain topography, and b) the municipality scale, using the limits of the 11 municipalities covering the Vésubie watershed. MCDA helps decision-makers structure multi-faceted decisions and evaluate alternatives (e.g. sub-basins, municipalities) according to a set of criteria. Here, criteria include building density, average elevation, average river slope, vegetated area, distance from the main river, land cover, past wildfires and past landslides. Our analysis results in two separate rankings (one of sub-basins and one of municipalities) from lowest to highest risk of flash flooding. Depending on the scale chosen, the resulting risk ranking of some areas changes, leading to a new debate on how we should approach flash flood risk in Mediterranean mountain basins in order to take better decisions and limit economic impacts and loss of life in a changing climate.
Testing compound floods by a new oceanic-coastal model in Cuba: preliminary results.
Authors: Córdova de Horta Daniela , Córdova López Luis.F , Jodar-Abellan Antonio , Fullana Andres , Prats Daniel
Published: February 2023

Testing compound floods by a new oceanic-coastal model in Cuba: preliminaryresults.Daniela Cordova de Horta 1,2 , Luis. F Cordova Lopez 1 , Antonio Jodar-Abellan 2,3 , AndresFullana 2,4 , Daniel Prats 2,41 Technological University of La Habana, Cuba.2 University Institute of Water and Environmental Sciences, University of Alicante, Alicante, Spain.3 Spanish Research Council, Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Soiland Water Conservation Group, Murcia, Spain.4 Department of Chemical Engineering, University of Alicante, 03690 Alicante, Spain.Abstract:Due to the climate change recognized in recent years, the danger on the coasts,at a global scale, has increased critically. This issue is associated with the increase in theglobal average temperature, which has the effect of raising the average sea level and theincrease in intensity and frequency of Extreme Meteorological Events (EME).Currently, more than 50% of the world's population lives in coastal regions and asignificant part in coastal areas vulnerable to flooding as a result of the rise in the meansea level, rainfall and river flooding. The simultaneous occurrence or brief succession ofthese hazards can cause flooding that generates impacts greater than those caused bythese events individually. In this study, a new technique of composite flood analysis isproposed in numerous urban-coastal areas and basins of Cuba by couplinghydrodynamic simulation tools. In particular, we present the results of the establishmentphase of the oceanic-coastal model called “Delft 3d Flow and Delft 3d Wave”, wherehurricanes Katrina, Isaac, Zeta and Ike were chosen. Likewise, the Era5 database wasused to generate the wind and pressure fields associated with hurricanes. In addition, theresults of a set of tests are presented to define the way of nesting and the best resolutionratios of the computation meshes of the different domains. Finally, statistics parameterswere applied to support the selection of the best alternatives by comparing our modelresults with the observations obtained by the National Oceanic and AtmosphericAdministration (NOAA) databases. From the author’s knowledge, the proposedmethodology can provide to planning policy makers very useful information in the faceof flood effects especially in a study area (Cuba) where flow registers from streamgauge stations are considerably scarce.
Petrophysical Inversions from Seismic Images detect and characterize Melt under Toba Caldera (Indonesia).
Authors: De Siena Luca , Magrini Fabrizio , Riel Nicolas , Diaferia Giovanni , Forni Francesca , Kaus Boris J. P.
Published: February 2023

The crustal feeding systems under volcanoes like Toba caldera in Sumatra remain largely unknown due to the lack of existing seismic arrays and consistent effort to apply advanced imaging techniques. Even if they were obtained, the interpretation of seismic anomalies in terms of melt content and geochemical differentiation would remain largely speculative without a framework that allows the connection between seismic attributes and petrophysical properties.We collected data from existing seismic arrays across Sumatra and applied ambient noise and earthquake tomography techniques. We used thousands of dispersion curves spanning both the shallow crust and the upper mantle using SeisLib1, the first open-access Python package for surface-wave tomography. We inverted the dispersion curves for phase-velocity maps at different periods, using a linearized-inversion algorithm based on the ray theory with a roughness damping constraint and an adaptive parameterization. Our results show low-velocity and high-attenuation sill-like structures under most of the northern and central portions of Toba calderas. We used the shear-wave velocity model as data and additional volcanological and geophysical data as constraints for a Bayesian inversion of magmatic composition and melt content under Toba. The forward model is provided by the MAGEMin3 code, which uses a Gibbs energy-minimization solver coupled with geological, geophysical, and volcanological information to identify portions of the crust where mafic sills are located. The Bayesian inversion quantifies from the melt content within the sill-like structures to the characteristics of the caprock overlaying them. It confirms the existence of a deep extended mafic sill reaching depths up to 12 km, currently disconnected from similar pockets of melt underneath the Toba lake stalling at a similar depth.By coupling seismic and thermodynamical modeling, we invert for (petro)physically-constrained quantitative images of the current state of a volcano. These images provide a cornerstone for a temporal description of volcanological responses based on physical modeling.1) Magrini, Fabrizio, et al. "Surface-wave tomography using SeisLib: a Python package for multi-scale seismic imaging" Geophysical Journal International (2022). ggac236, https://doi.org/10.1093/gji/ggac236.
2) Riel, Nicolas, et al. "MAGEMin, an efficient Gibbs energy minimizer: Application to igneous systems" Geochemistry, Geophysics, Geosystems (2022).
Constructing a pollen proxy from low-cost Optical Particle Counter (OPC) data processed with Neural Networks and Random Forests
Authors: Mills Sophie , MacKenzie Rob , Pope Francis
Published: February 2023

Pollen allergies affect a significant proportion of the global population, and this is expected to worsen in years to come. There is demand for the development of automated pollen monitoring systems to progress from conventional manual sampling techniques. Low-cost Optical Particle Counters (OPCs) are conventionally used for measuring particulate matter and have attractive advantages of real-time high time resolution data and affordable costs. Our study asks whether low-cost OPC sensors be used for meaningful monitoring airborne pollen and utilises data from the EUMETNET Autopollen ADOPT – COST Action Intercomparison Campaign (2021) in Munich, Germany.We employ a variety of methods, including supervised machine learning techniques, to construct pollen proxies from hourly-average OPC data and evaluate their performance. The most successful methods are supervised machine learning Neural Network (NN) and Random Forest (RF) methods, trained from pollen concentrations collected from a Hirst-type sampler. These perform significantly better than using a simple particle size-filtered proxy or a Positive Matrix Factorisation (PMF) source apportionment pollen proxy. We developed a collection of models - varying by model type, input features (including particle size and meteorological data) and target variable (i.e. total pollen vs selected pollen taxa) - and evaluated their suitability for constructing a pollen proxy. The results show that such models can construct useful information on pollen from OPC particle size data with Spearman correlation coefficients up to 0.85 and coefficients of determination up to 0.67. Model-constructed proxies demonstrated an ability to distinguish high pollen events with promising results (F1 Scores up to 0.83) and to follow monthly and diurnal trends in pollen. We discuss the suitability of OPCs for monitoring pollen and offer advice for future progress. We demonstrate an attractive alternative for automated pollen monitoring that could provide valuable and timely information to the benefit of pollen allergy sufferers.
Fundamental drivers of nutrient diffusion in soils - a comprehensive data synthesis based on microdialysis studies
Authors: Wanek Wolfgang , Finta Denisa , Inselsbacher Erich
Published: February 2023

The bioavailability and delivery of nutrients (solutes) to plant roots and soil microbes is governed by diffusive processes. According to Fick’s first law solute diffusion is driven by the diffusivity of the solute, the concentration gradient and the path length. We first shortly review the main factors potentially affecting these drivers i.e. the diffusivity (solute-soil interactions including ion exchange and other sorption reactions, microbial metabolism), the concentration gradient (source-sink relations via mobilization through biotic and abiotic reactions and solute uptake by organisms) and the path length (soil water filled pore space, pore size distribution, texture). Then, based on data synthesis of available microdialysis studies we provide evidence for the ranking of these factors in soils, depending on soil horizon (organic versus mineral soil), fertilization (agriculture versus forests), nutrient form (ammonium versus nitrate versus free amino acids; nitrate versus phosphate) and soil moisture, including drying-rewetting. Microdialysis represents a relatively recent minimal invasive technique for in situ and lab use to measure rates of diffusive solute (nutrient) transport on a microscale level. Since its first application in soil in 2005, this technique has provided unique, non-isotopic and non-destructive insights into major drivers of solute transport in soils, with ~45 studies published thus far.
Evaluate parameterizations of cloud droplet spectral dispersion by using worldwide aircraft data
Authors: Wang Hengqi , Peng Yiran , Lu Chunsong , Quaas Johannes
Published: February 2023

Increased aerosol potentially impacts the cloud droplet spectrum, which in turn affects the aerosol-cloud interaction (ACI), known as the dispersion effect (DE). To consider DE in general circulation models (GCMs), many parameterizations have been proposed, but there are relatively few quantitative and global evaluations due to lacking suitable data and methodology. Additionally, both observations and numerical simulations confirmed that DE has opposite effects on ACI in aerosol- and updraft-limited regimes, but whether this effect can be reproduced by parameterizations has no clear conclusion until now. In this study, we used a liquid water content (LWC) binning method and worldwide data (China, Canada, Brazil, and Chile) to evaluate six dispersion parameterizations, namely Martin94, RLiu03, PengL03, Liu08, LiuLi15, and Zhang22. The LWC binning method ensures the difference between ACI values calculated by the cloud droplet number concentration and the effective radius is mainly caused by DE, which makes the quantitative calculation of DE possible. The results show that 1). DE has a weakening effect on ACI in the aerosol-limited regime, but an enhanced effect in the updraft-limited regime; 2). empirical parameterizations (Martin94, RLiu03, PengL03, and Liu08) can only show the weakening effect of DE on ACI, leading to an underestimation (-29% ~ -42%) for calculated ACI, especially for the updraft-limited regime; 3). both LiuLi15 and Zhang22 can reproduce the opposite effects of DE on ACI in different regimes, so we recommend giving priority to the LiuLi15 and the Zhang22 schemes when calculating DE in GCMs.
A Merger-Formation Bow Echo Caused by Low-Level Mesovortex in South China
Authors: Liu Qiqing , Xu Xin , Zhao Kun , Zhou Ang
Published: February 2023

Based on operational radar observations and high-resolution analyses from the Variational Doppler Radar Analysis System (VDRAS), a bow echo producing high-winds and heavy rainfall that occurred over South China in the pre-rainy season is studied. Results show that this bow echo developed from a quasi-linear convective system (QLCS) and acquired a well-defined bow shape after merging with a pre-line convective cell (CC). Interestingly, the rear-inflow jet (RIJ), which has been well recognized to play a key role in the formation of a bow echo, was absent in this merger-formation bow echo (MFBE). This is ascribed to the weak cold pool and line-end vortices generated within the QLCS as it developed in the monsoon environment of high humidity and weak low-level vertical wind shear.A new pathway of bow echo formation was proposed instead, which highlighted the importance of the low-level mesovortex (MV) on the leading edge of the QLCS. The MV originated from a weak vertical vorticity band ahead of the QLCS. Vertical vorticity budget analyses revealed that the enhanced stretching effect during the QLCS-CC merger was the main cause of the growth of the MV. The well-developed MV thereby provided a RIJ-like flow wrapping cyclonically from north of the QLCS, forcing the QLCS to distorted into a bow echo. This MV contributed foremost to the near surface gales as well.Combined with the well-resolved dynamical processes aforementioned, observations from an S band polarimetric radar are employed, aiming to uncover the microphysical and dynamical structures and their interaction processes accounting for the heavy rainfall. The precipitation was shown to be featured of high concentration of large hydrometeors, with maxima basically limited within the intensified MV. The deep QLCS developing far above the freezing level favored for significant ice-phase processes, further enhancing rain rate through melted graupel and hail. High spatiotemporal correlation between the precipitation extremes and the MV suggests the non-negligible role the MV played to determine the microphysics process of this precipitation, which required more detailed researches next.
Effects of dynamic changes of desiccation cracks on preferential flow: Experimental investigation and numerical modeling
Authors: Luo Yi , Zhang Jiaming , Zhou Zhi , Pablo Aguilar López Juan , Greco Roberto , Bogaard Thom
Published: February 2023

Preferential flow induced by desiccation cracks (PF-DC) has been proven to be an important hydrological effect that could cause various geotechnical engineering and ecological environment problems. Investigation on the PF-DC remains a great challenge due to the soil shrinking-swelling behavior. This work presents an experimental and numerical study of the PF-DC considering the dynamic changes of DC. A soil column test was conducted under wetting-drying cycles to investigate the dynamic changes of DC and their hydrological response. The ratio between the crack area and soil matrix area (crack ratio), crack aperture and depth were measured. The soil water content, matrix suction and water drainage were monitored. A new dynamic dual-permeability preferential flow model (DPMDy) was developed, which includes physically-consistent functions in describing the variation of both porosity and hydraulic conductivity in crack and matrix domains. Its performance was compared to the single-domain model (SDM) and rigid dual-permeability model (DPM) with fixed crack ratio and hydraulic conductivity. The experimental results showed that the maximum crack ratio and aperture decreased when the evaporation intensity was excessively raised. The self-closure phenomenon of cracks and increased surficial water content were observed during low evaporation periods. The simulation results showed that the matrix evaporation modeled by the DPMDy is lower than that of the SDM and DPM, but its crack evaporation is the highest. Compared to the DPM, the DPMDy simulated a faster pressure head building-up process in the crack domain and higher water exchange rates from the crack to the matrix domain during rainfall. Using a fixed crack ratio in the DPM, whether it is the maximum or the average value from the experiment data, will overestimate the infiltration fluxes of PF-DC but underestimate its contribution to the matrix domain. In conclusion, the DPMDy better described the underlying physics involving crack evolution and hydrological response with respect to the SDM and DPM. Further improvement of the DPMDy should focus on the hysteresis effect of the SWRC curve and soil deformation during wetting-drying cycles.
Neogene Mantle Dynamics of Western Mediterranean Region Constrained by Basalt Geochemistry and Residual Depth Anomalies
Authors: Tien Chia-Yu , White Nicky , Maclennan John , Conway-Jones Benedict , Holdt Megan
Published: February 2023

There is considerable interest in combining a range of geophysical, geochemical and geomorphic observations with a view to estimating the amplitude, wavelength and depth of mantle thermal anomalies on a global bases. Here, we wish to explore how forward and inverse modelling of major, trace and rare earth elements can be exploited to determine melt fraction as a function of depth for a mantle peridotitic source. Our focus is on an area that includes the Iberian Peninsula where previous work shows that long-wavelength topography is probably generated and maintained by sub-plate thermal anomalies which are manifest by negative shear-wave velocities. Geological and geomorphic studies suggest that this dynamic support is a Neogene phenomenon. 48 newly acquired Neogene basaltic samples from Spain were analyzed and combined with previously published datasets. Both major element thermobarometry and rare earth element inverse modelling are applied to estimate melt fraction as a function of depth. In this way, asthenospheric potential temperature and lithospheric thickness can be gauged. These estimates are compared with those obtained from calibrated shear-wave tomographic models. Our results show that potential temperatures and lithospheric thicknesses are 1250-1300 °C and 65-70 km, respectively. These values broadly agree with calibrated tomographic models which yield values of 1300-1350 °C and 45-70 km. We conclude that a region encompassing Iberia is dynamically supported by a combination of warm asthenosphere and thinned lithosphere. This conclusion broadly agrees with independently obtained residual depth anomalies which indicate that the Western Mediterranean region probably has moderately positive dynamic support.
Environmental evolution and landslide hazard assessment in high mountainous areas based on UAV multi-sensors
Authors: Chang Kuo-Jen , Huang Mei-Jen , Tseng Chun-Wei , Wahyuni Ayusari
Published: February 2023

The vigorous development of geospatial information technology has not only achieved good results in land monitoring, but has also been gradually extended to other application fields. Hazards monitoring is one of the important applications. Geospatial information can be obtained through surveying and mapping technology, and through multi-temporal geospatial data, the production, migration and migration of debris deposits can be quantitatively evaluated in a reasonable time and space in catchment scale. In recent years, the development and integration of MEMS technology has contributed to the rapid development of UAV measurement. This goal can be achieved due to the advantages of UAVs, such as efficiency, timeliness, low cost, and easy operation in severe weather conditions. The real-time, clear and comprehensive low- and middle-altitude photos of the area can be used as the most basic and important spatial information for research and analysis. Based on the aforementioned technologies, we selected two specific landslide-prone areas for UAV photogrammetry data acquisition. The two sites of forestry road and nursery situated in the high mountainous forestry in southern Taiwan. In order to evaluate potential hazards and hazard monitoring, the multi-temporal high precision terrain geomorphology in different periods is essential, so as to assessment the hazards and for early warring. For these purposes, we try to integrate several technologies, especially by unmanned aircraft system imageries and existed airphotos, to acquire and to establish the geoinfomatic datasets. The methods, including, (1) Remote-sensing images gathered by UAS and by aerial photos taken in different periods; (2) field in-situ ground control points and check points installation and geomatic measurement; (3) 3D geomorphological virtual reality model construction; (4) Geologic, morphotectonic and landslide micro-geomorphologic analysis; (5) DTM of difference from multi-temporal dataset to evaluate the topographic and environment changes. The main achievements are four: a) UAV photogrammetry and accuracy analysis in the study area; b) Construction of a 3D terrain model in the study area; c) Geological survey of collapsed areas; d) Multi-year spatial information variation analysis. According to the findings, landslides activated continuously in different periods and different areas. In different sections of the riverbeds, different degrees of siltation or erosion have been identified, so regular monitoring and potential hazard assessment are still necessary.
Analysis of terrain deformation induced by groundwater overexploitation using InSAR, wavelet analysis and hydrogeological data
Authors: Meldebekova Gauhar , Yu Chen , Mills Jon , Li Zhenhong , Song Chuang
Published: February 2023

Residents of Kabul, Afghanistan have historically relied on groundwater delivered from unconfined aquifers. However, recent drought events and population growth have resulted in withdrawing groundwater beyond sustainable rates and water level decrease. Groundwater overexploitation might have induced various magnitudes of ground subsidence, however, the issue had been overlooked.  In this study, we assessed the spatial and temporal evolution of ground deformation in Kabul and analysed the main governing processes.Deformation rates were extracted using InSAR SBAS time-series analysis of C-Band Sentinel-1 products from both ascending and descending orbits acquired from 2014 to 2019.  The analysis revealed Line-of-Sight (LOS) mean velocity accounting for -4.08 and -4.3 cm/year for ascending and descending tracks, respectively. High correlation coefficient of 0.75 and the low RMSE of 0.60 cm/year suggest that the two measurements are consistent. To overcome the inherent limitation of InSAR- measurements being made in LOS direction only, multi-geometry data fusion was employed by combining two independent LOS measurements to estimate vertical and horizontal components of displacement.  We delineated four subsidence bowls with highly variable spatial extent and deformation magnitudes in four aquifers present within the city boundaries, the largest of which is detected in Upper Kabul basin area with the vertical component reaching -5.3 cm/year and horizontal motion accounting for 1 cm/year.  The InSAR-derived subsidence time-series results were interpreted in relation to the spatio-temporal variations of hydrological and geotechnical conditions of the study area to identify the triggering factors of subsidence. The trend observed in the deformation time-series and groundwater level change shows a good agreement, suggesting that groundwater drawdown is largely a function of groundwater level change.  Wavelet analysis analysis allowed to distinguish long-term subsidence from recurring clay shrink-swell hazard in the region.  Furthermore, the susceptibility of the aquifers to consolidation was found to be largely caused by the prevalence of fine-grained sediments in the subsurface, such as clay and silt, thus differential consolidation in the area is a function of variation in thickness and types of the lithology of the base sediment.  In the context of climate change and increasing urban sprawl in Kabul, monitoring ground deformation using the satellite InSAR is an invaluable tool that provides new opportunities to inform not only subsidence hazard mitigation plans, but also approaches for sustainable management of groundwater resources and for improved planning of operations such as Managed Artificial Recharge (MAR) of aquifers.