bluuebunny/crossref_metadata_2025 huggingface dataset:
Implications of Bouguer Gravity Structure Under Major Lunar Basins
Authors: Smith David E , Goossens Sander , Zuber Maria T
Published: February 2023

Analysis of the lunar Bouguer gravity field under major basins reveals how gravity varies with spherical harmonic degree L and, potentially, with depth (to relate the two we use a relationship based on point masses).  We have studied 19 lunar basins based upon a GRAIL 1200 degree and order gravity model (GRGM1200B).  The vertical component of Bouguer gravity shows how the gravity is distributed in spherical harmonic degree between the lowest degree, 2, and the highest degree, 1200. Under each basin, this gravity spectrum of accelerations per individual spherical harmonic degree shows a benign region for L from 800 to 100, a range of approximately 20 km immediately below the surface, consistent with the observation that the upper crust is largely homogenous (Zuber et al., 2013). A region of more varied gravity signal occurs down to L~20, approximately 60 km deeper. The basin gravity signal merges with the deep interior at L~10, approximately 150 km below the surface. A set of profiles over latitude or longitude through an individual basin anomaly shows how the magnitude of the gravity signal changes with depth as it passes from the annular moat to the central high of the anomaly; all of which takes place between L~100-20, a depth range estimated to be ~20-80 km.  However, all basins are different to some extent. Outside of the basin anomaly the gravity spectra are relatively benign from just below the surface to L~40, a depth of approximately 45 km and consistent with the approximate average thickness of the lunar crust.  An exception to the general characteristics of the spectra of basins is South Pole-Aitken (SPA) which indicates a structure with few variations that is very similar to the regions that have near zero Bouguer gravity at the surface with no large anomalies in the top 100 km. We interpret this result for SP-A as a result of its largely compensated state.
Local vs regionalised deep learning models for groundwater level simulations in the Seine basin.
Authors: Chidepudi Sivarama Krishna Reddy , Massei Nicolas , Henriot Abel , Jardani Abderrahim , Allier Delphine
Published: February 2023

This study aims to investigate the use of deep learning techniques, with or without data pre-processing for simulating groundwater levels. Two approaches are compared: (1) a single (local) station approach, where a separate model is trained for each station, and (2) a multi-station approach, where a single model is trained using data from multiple stations in the study area. In the latter approach, static catchment attributes and dynamic meteorological (precipitation and temperature) and climate (sea level pressure, etc) inputs are used to model groundwater levels in the Seine basin. By including static variables corresponding to (hydro)geological or geomorphologic watershed characteristics in the deep learning model, we aim to improve the accuracy of simulations and better understand the factors that influence groundwater levels in the Seine basin. Additionally, we are assessing the potential of using MODWT as a pre-processing method in both approaches. For both single-station and multi-station approaches, without including static variables, results show that MODWT pre-processing helps the models in extracting the relevant information which in turn improves the simulations. Additional ongoing works are being conducted including static/watershed characteristics to assess whther these could help improving the modeling results.
Magnetic connectivity from the Sun to the Earth: Impact of the magnetic modelling and input magnetic map
Authors: Perri Barbara , Kennis Silke , Brchnelova Michaela , Baratashvili Tinatin , Kuzma Blazej , Zhang Fan , Lani Andrea , Poedts Stefaan
Published: February 2023

Connectivity between our star and our planet is a huge but necessary challenge. Indeed, remote-sensing instruments allow us to observe with great details the surface of the Sun, while in-situ measurements let us see the consequences at Earth. However, it it not always easy to understand the link between the two, thus preventing us from understanding the propagation of physical effects. One way to chase this connection is to use the magnetic field: although not visible, open magnetic field bathes the entire heliosphere, and has a major influence on plasma and particle events such as CMEs or flares. We can typically use numerical simulations to estimate the magnetic field lines pattern, and thus help connecting remote-sensing with in-situ observations. In this study, we will present our computation of the magnetic connectivity through the heliosphere by coupling the MHD codes COCONUT for the solar corona and EUHFORIA for the inner heliosphere. MHD codes are usually too slow to compute connectivity on a near-real time cadence, but this chain of model can be optimised to run in less than 6 hours, which allows refined tracking within a single day. We will explain how the coupling between the code operates, as it effects the tracing of the magnetic field lines. We will also explain how to provide uncertainties with this method. We will first show the validation of our method by comparison with PFSS and wind ballistic mapping, for both polar and equatorial open coronal holes, on several test cases that were already used in previous studies. This will allow us to discuss the impact of the magnetic modelling on the connectivity estimation. Finally, we will also discuss the impact of the input magnetic map by comparing 20 different runs for the same Carrington rotation at minimum of activity, based on various maps from different providers.
Investigating soil organic matter dynamics in topsoil and subsoil by burying isotopically labelled litter substrate for four years
Authors: Begill Neha , Don Axel , Poeplau Christopher
Published: February 2023

Subsoils have gained increasing attention due its slower soil organic carbon (SOC) turnover than in topsoil. Thus, subsoil with low content of mineral associated organic matter but a large number of exchange sites on mineral surfaces represents the potential to accumulate and sequester carbon (C). Generally, it has been assumed that the carbon turnover mechanism in topsoil and subsoil is influenced by similar environmental factors, with the difference of a lower C content in subsoil. In contrast, diverse abiotic variables prevalent in subsoils, like low temperature, high moisture, nutrient availability, etc., have been shown to imply different processes influencing C turnover in subsoils. Therefore, differences in processes and factors affecting SOC turnover in topsoil and subsoil are incompletely identified and understood.Our objective is to investigate whether C decomposition and stabilisation mechanisms in topsoil and subsoil differ given the same added substrate content, as well as how it responds to increasing substrate C content. To assess these questions, a long-term (total duration 20-year) field incubation experiment was conducted at three different locations with varied soil textures in which soil was mixed and labelled with isotopically (13C) enriched beech litter substrate with different C contents of 8, 16, 32, and 64 g substrate kg-1 in topsoil (10 cm) and 2, 4, 8, and 16 g substrate kg-1 in subsoil (60 cm), filled in mesocosms, and buried. Soil samples were collected after one, two, and four years. Soil was fractionated into particulate organic matter (>20µm) and mineral-associated organic matter (<20µm) to find out how carbon is stabilised in these fractions, and stable C isotopes were measured. Our results indicate that the decomposition of the identical litter substrate strongly depends on the soil depth. The results of four years of buried field-microcosms will be presented, which will shed more light on differences in mechanisms responsible for SOC dynamics and the fate of litter substrate into different SOC pools of topsoil and subsoil. 
Land-use following a middle-road socio-economic pathway (SSP2) is not enough to recover mammal populations in Southern-Asia
Authors: Pinto da Silva André , Thörn Filip , Malchow Anne-Kathleen , Zurell Damaris , Cabral Juliano
Published: February 2023

Land use is the main direct driver of biodiversity loss and Southern-Asia is, globally, one of the regions under the highest land-use change. Here we estimate how mammals that play a key role in the ecosystem functioning will cope with landscape transformations. We used the a state-of-the-art spatially-explicit agent-based model (RangeShifter) combining local density-dependence on fecundity, stage-structured demographics and dispersal to predict the occupancy and abundance for large-body size carnivorous species (Panthera tigris, Panthera pardus) mid-sized and small carnivorous (Cuon alpinus, Felis chaus, Vulpes vulpes and Prionailurus bengalensis) and two Cetartiodactyla species (Sus scrofa and Gazella benetti) in Southern Asia. In addition, we estimated how species-richness changed through time. The model was projected to the period 1850 to 2100 under two socio-economic pathways, representing an intermediate scenario (SSP2-4.5) and a fossil-fueled development scenario (SSP5-8.5). We found mixed-response to land-use across species. We estimate the mean total proportion of remaining individuals to be 0.60 (SD = 0.24) under SSP2 and 0.64 (SD = 0.37) under SSP5 compared to baseline land use in 1850. The drop in the total number of occupied cells is of lower magnitude (SSP2: mean = 0.82, SD = 0.27; SSP5: mean = 0.84, SD = 0.32). Mean species richness per cell followed a decline throughout the 20th century (mean = 0.90, SD = 0.15) followed by increase from current time up to 2100 under both scenarios (SSP2: mean = 0.95, SD = 0.18; SSP5: mean = 0.97, SD = 0.22). Our results support biotic homogenization with spread of widespread species and restriction of forest-specialists. We confirm a disproportionate and negative influence of loss of non-disturbed patches, and lower landscape permeability in large mammals, potentially leading to considerable change in mammalian biomass in the ecosystem. These findings suggest that a middle-road socio-economic pathway (SSP2) is not enough to maintain or recover populations compared to pre-disturbance levels.
Lightning activity over central Europe in years 2017-2022 (analysis of ISS-LIS data)
Authors: Kolínská Andrea , Kolmašová Ivana , Price Colin , Santolík Ondřej
Published: February 2023

We analyze the lightning activity over central Europe from 2017 to 2022 using the optical data from the Lightning Imaging Sensor (LIS) on board the International Space Station (ISS). The area of interest covers a central European region limited by 54.5° N, 7.5° E and 44.5° N, 22.5° E. A total number of 68192 lightning flashes was detected during 1805 ISS orbital overpasses. This study compares the lightning activity in central Europe to the global lightning activity and investigates the impact of the COVID-19 pandemic. While there is a global reduction of the lightning activity during the lockdowns in 2020, no significant decrease is observed in central Europe.On the territory of Czechia, the highest density of flashes was detected in the northwestern part of the country. We combine the ISS-LIS data with measurements of the Shielded Loop Antenna with Versatile Integrated Amplifier (SLAVIA) detectors located in this region. The measurements of the ISS-LIS and SLAVIA detectors are combined with data from the World Wide Lightning Location Network (WWLLN) or Global Lightning Dataset (GLD360) in order to understand the correlation between electromagnetic radiation from selected lightning flashes and their optical characteristics observed from space.
The incorporation of 250 m soil grid textural layers in the NOAH-MP land surface models and its effects on soil hydrothermal regimes
Authors: Ishola Kazeem , Sati Ankur , Demuzere Matthias , Mills Gerald , Fealy Rowan
Published: February 2023

Effective representation of soil heterogeneity in land surface models is crucial for accurate weather and climate simulations. The NOAH-MP land surface model uses dominant soil texture from State Soil Geographic (STATSGO)/Food and Agriculture Organization (FAO) datasets, considerably introducing uncertainty in the simulation of soil hydrothermal changes and terrestrial water and energy fluxes, at a fine scale. This study investigates the likely added value of incorporating an alternative high resolution soil grid data at different depths, for a better representation of soil hydrothermal dynamics in NOAH-MP v4.3. The model is set up at 1 km grid space over all Ireland domain and soil layer thicknesses of 0.07, 0.21, 0.72 and 1.55 m, with a cummulative soil depth of 2.55 m. The thicknesses are selected to match the layers of initial soil input fields. Model experiments are carried out based on two soil data options namely, (1) the STATSGO/FAO dominant soil texture and (2) the 250 m global soil grid textural compositions from the International Soil Reference and Information Centre (ISRIC), in combination with PedoTransfer Functions (PTFs). The current model integration is applied within the high resolution land data assimilation (HRLDAS) framework to simulate soil temperature and soil liquid water, and evaluated for wet and dry periods using observations from the newly established Terrain-AI data platforms (terrainai.com). Ultimately, the study highlights the importance of using realistic dynamic soil information, which could provide insightful scientific contributions to better monitor surface climate and the influences on land use and land management under climate change.
First results of a multiphysics experiment at Krafla geothermal volcano: Seismicity pattern from joint hypocenter-3D travel-time tomography inversion
Authors: Glück Elisabeth , Garambois Stephane , Vandemeulebrouck Jean
Published: February 2023

The IMPROVE ITN project focuses its interdisciplinary approach on a better understanding of volcanic systems, partly with multiphysics imaging methods. One target of this project is Krafla, a volcano of the northern volcanic zone in Iceland, which erupted last during the Krafla fires in the 1970s and 80s. Also, in this period the national power company of Iceland (Landsvirkjun) built a geothermal powerplant inside the Krafla caldera, increasing the knowledge of the complex system through electro-magnetic and seismic imaging methods and seismological observations.Nonetheless, the high-resolution imaging of the magmatic system still poses a challenge just as the origins of the seismicity remain poorly understood. To tackle these questions a multi-physics experiment has been carried out in June and July 2022.The experiment included an active 3D ERT experiment to image the first kilometre of the geothermal system, the densification of the already existing MT measurements and the installation of a dense seismic array of 100 stations deployed for 1 month. In addition, Landsvirkjun provided continuous seismic data acquired from 12 broadband 3-C stations over the last 8 years. With this dataset we aim to better understand temporal and spatial changes in stress, the anthropogenic influence on the system through the geothermal industrial activity and to image shallow magmatic pockets. The broadband data of the 12 permanent seismic stations were used to analyse the seismicity with STA/LTA and Template Matching methods. The first P- and S-wave onsets were automatically picked and inverted using a joint hypocentre-velocity approach based on ray theory. It provides a new 3D P-wave velocity model and refined locations of the seismicity. This updated earthquake catalogue, consisting of seismicity of the last 8 years, covers a deflation and an inflation period of Krafla, yielding the opportunity to better investigate the seismic properties in relation with geothermal industrial activity and long-term deformation of the volcano. The variability of the P-wave velocity will be compared to the available 3D resistivity models obtained from previous MT measurements. In the future, the dense seismic array will be used for high resolution imaging at the geothermal upflow-systems and jointly interpreted with the ERT and MT data, while the 12 broadband recordings will be used for seismic noise monitoring purposes.
The role of passive shallow cumuli in the transition from shallow to deep convection
Authors: Vraciu Cristian-Valer
Published: February 2023

The initiation of deep convection in a diurnal cycle is still one of the most important uncertainties in a climate numerical model. This is partially due to our poor understanding of the physical mechanisms leading to the transition from shallow to deep convection. In this work, we discuss the role of shallow cumulus clouds in the initiation of deep convection. By using a simple entraining plume model, we show that the interaction between an active and a passive shallow cumulus helps the former to reach higher altitudes and, in the right conditions, may initiate deep convection. It is also shown that the organization of passive and active clouds due to the formation of cold pools may act as a positive feedback. Furthermore, based on the proposed mechanism, a stochastic triggering function is derived, which can be implemented in climate models. As an important feature, the stochastic function is scale-aware, which makes it suitable for simulations at the gray-zone.
A vulnerability-adjusted approach to global flood risk mapping
Authors: Fox Sean , Agyemang Felix , Hawker Laurence , Neal Jeff
Published: February 2023

Global flood risk maps combine data from hydrodynamic models with gridded population or GDP data to estimate the amount of people or wealth likely to be exposed to future flood events. These estimates rarely incorporate measures of social vulnerability, which is a key source of variation in outcomes for exposed populations. They also use arbitrary return period thresholds, which can disguise potentially catastrophic hazards. To address these limitations, we integrate annual average exceedance probability estimates from a high-resolution (~90m) flood model with gridded population and economic data to create a global vulnerability-adjusted risk index for flooding (VARI Flood). This human welfare-centred approach radically alters how we perceive the geography of risk and could be used as a complement to traditional population or asset-centred approaches. We present global results for both unadjusted and vulnerability-adjusted risk at the subnational (Admin 2) level; country case studies illustrate how accounting for vulnerability changes the perceived subnational geography of risk. Globally, adjusting for vulnerability significantly reduces the total number of people estimated to be at ‘high risk’ from  over 575 million to about 117 million. However, this latter estimate is likely an underestimate given the relatively coarse resolution of the economic data available, which disguises variation in vulnerability between communities within large cities and urban regions. Given the increasing concentration of the global human population in cities, there is an urgent need to improve the resolution of vulnerability mapping within large human settlements to inform mitigation measures. 
Evaluation of Climate Data from ECMWF Reanalyses over Siberia and the Russian Far East
Authors: Clelland Andrew , Marshall Gareth , Baxter Robert
Published: February 2023

Reanalysis data provide a complete picture of the past climate by re-running previous forecasts using modern methods and assimilating with observations. In this work three reanalysis datasets from the European Centre for Medium-Range Weather Forecasts (ECMWF), ERA-Interim, ERA5 and ERA5-Land, were validated against data from 29 meteorological stations across Siberia and the Russian Far East. ERA5 offers improved spatial and temporal resolutions compared to ERA-Interim, as well as starting twenty years earlier in 1959 and being continually updated to the present day with little delay. ERA5-Land replays the land component of ERA5 over an improved 9km spatial resolution and the dataset begins in 1950. The validation was conducted at daily, monthly, seasonal and annual timescales for seven climate variables first to 1979, then additionally to 1959 for ERA5 and ERA5-Land. We found that the snow depth values in ERA5 are only assimilated with meteorological station data from 1992 onwards, leading to significant and inhomogeneous overestimations before this time. As ERA5-Land uses the ERA5 values as its boundary conditions, the snow depth values in this dataset are further from the observations. The mean sea level pressure in the reanalyses is closest to those from the meteorological stations. The daily minimum 2-metre air temperature is noticeably weak during the summer months, however on broader timescales the reanalyses perform very well for the minimum, average and maximum temperatures. Total precipitation and wind speed consistently have the lowest correlations at all temporal and spatial resolutions. Despite the increased spatial resolution, we found no improvement to using ERA5-Land over ERA5, however we would recommend using ERA5 over ERA-Interim due to the larger amount of data available.
Interdisciplinarity through extra-curricular projects
Authors: Lazar Alina Stefania
Published: February 2023

"After class" activities are very useful for most students, especially since there are some of them who don't have the best family life. In the case of such a young person, extracurricular activities are welcome because they can change his outlook on life and guide him to a better path. If at home he lacks the "mentor", the person to guide him, the young person will look for one outside, so it is advisable to be a responsible adult, a teacher, a guideSuch activities are of real importance all the more so as we live in a world dominated by the mass media, here referring to the television, computer and internet, which do nothing but contribute to the transformation of our children into incapable persons to control oneself behaviorally, emotionally.The extracurricular and extracurricular projects have the broadest interdisciplinary character, they offer the most effective ways of forming children's character, because they are the educational factors closest and most accessible to their souls. Having an attractive character, children participate in an atmosphere of good will and optimism, with zest and dedication to such activities.Students who consistently participate in extracurricular and extracurricular activities have a lower level of aggression, something that should be taken into account by students, parents and teaching staff, and last but not least by the higher authorities, in order to reduce violence. The various extracurricular activities that students have access to, promoted by the mass media, provide a favorable framework for energy consumption and the release of accumulated tension.In this work we will detail the methods with which the teachers of Forest Technological High School of Ramnicu Valcea have implemented a suite of extra-curricular activities, which led not only our students, but also our teachers, to develop their personal and professional skills. Moreover, we show how these activities strengthen the bond between the teacher and the student, while also flourishing their abilities to make new friends amongst their peers and even beyond.
Global changes in the hydroclimate of the Last Millennium: Evidences from reconstructions and simulations
Authors: Roldán Pedro , González-Rouco Jesús Fidel , Smerdon Jason , García-Pereira Félix
Published: February 2023

Global changes have been found in simulated and reconstructed temperatures during the Last Millennium (LM), mainly associated to changes in the Earth’s energy balance like those during the periods of the Medieval Climate Anomaly (MCA; ca. 950-1250 CE) and the Little Ice Age (LIA; ca. 1450-1850 CE), respectively characterized by warmer and cooler conditions over many regions. Even if the impact of these changes in the hydroclimate is not fully understood, evidences of coordinated changes in the hydroclimate of distant regions can be also found in reconstructions from areas of North America, Europe and the Mediterranean basin, South America, Eastern Africa and Monsoon Asia. The timing of such changes suggests a link to the MCA and the LIA, while other areas like Southeast Asia and the Indo-Pacific also show coordinated changes in the hydroclimate of the LM, but without a patent link to the periods of MCA and LIA.To better assess these coordinated changes in the hydroclimate of distant regions, and whether they also extend to other periods of the LM different from the MCA and the LIA, evidences from reconstructions and simulations have been compiled, including: a compilation of 92 reconstructions reporting changes from wetter to drier or from drier to wetter conditions in the transition from MCA to LIA; reconstruction-based products like the Drought Atlases for Europe (OWDA), North America (NADA), Asia (MADA), Mexico (MXDA) and Eastern Australia and New Zealand (ANZDA); hybrid products like the Paleo Hydrodynamics Data Assimilation product (PHYDA) and the Last Millennium Reanalysis (LMR); and model simulations from the Community Earth System Model - Last Millennium Ensemble (CESM-LME) and the Coupled Model Intercomparison Project Phase 5 (CMIP5) and 6 (CMIP6).The comparison between proxy-based datasets and model simulations has allowed to obtain robust conclusions regarding the behavior of the hydroclimate of different regions and to deeply analyze the impact of external forcing and internal variability on hydroclimate changes. In tropical areas, changes have been mainly associated to alterations in the position and intensity of the Intertropical Convergence Zone (ITCZ), while in extratropical areas the alteration of variability modes like the Northern (NAM) and Southern Annular Modes (SAM) may have had a major role in the response of hydroclimate to changes in external forcing. 
Mixing magnitude and extent within the benthic biolayer for different morphology types
Authors: Monofy Ahmed , Boano Fulvio , B.Grant Stanley
Published: February 2023

Mixing between water column and sediment is a crucial physical process for the fate of nutrients and for the biogeochemical reactions in the stream ecosystem. There are two factors that characterize this mixing process: the mixing magnitude at the sediment water interface, which controls the amount of solutes exchange between water column and its underlying sediment layer; and the mixing extent that defines how quickly the mixing rate decays with depth of the sediment laye.  The vertical mixing process has been shown to be well represented by a 1-D equivalent diffusivity model with exponentially decaying profile in the vertical direction. This exponential profile is controlled by two parameters: the effective diffusion at the sediment water interface, that is equivalent to the mixing magnitude, and the decay coefficient of the exponential, that represents the reciprocal of the mixing extent.The 1-D diffusivity model was applied to a large dataset of experiments from literature that were conducted with conservative solutes on three different morphology types: flat beds, dunes and ripples, and alternate bars. The mixing magnitude and extent appears to be the largest in alternate bars, the smallest in flatbed and intermediate in dunes and ripples. Afterwards, the dependence of the mixing magnitude and mixing extent on stream and sediment characteristics was studied to derive a regression model to infer the values of the mixing controlling parameters from stream and sediment characteristics. This regression model was developed in dimensionless form using the Multiple Linear Regression (MLR) technique.  The regression formulae demonstrate no dependence of the mixing magnitude on morphology type, while it is significantly correlated to the permeability Reynolds number (Re_k) that depends on sediment permeability, shear velocity and water viscosity. On the other hand, the mixing extent of solutes within the benthic biolayer can be categorized based on the morphology type. Specifically, for flat beds the mixing extent exhibits different trends of dependance on the permeability Reynolds number due to the dominance of different physical process for each interval of Re_k. Instead, for dunes and ripples the mixing extent is monotonically correlated to the bedform (ripple or dune) wave number, as expected from literature. Finally, due to the limited number of experiments on alternate bars we were not able to derive a robust and reliable regression formula for this morphology type. Therefore, more experiments under different conditions should be performed with alternate bars. These results help to unravel the influence on mixing processes of different characteristics of streams and their sediments.
Improving GNSS data analysis with undifferenced integer ambiguity resolution
Authors: Tang Longjiang , Wang Jungang , Nie Liangwei , Zhu Huizhong , Ge Maorong , Schuh Harald
Published: February 2023

Along with other space geodetics, the Global Navigation Satellite Systems (GNSS) technique has a profound impact on the realization of terrestrial reference frames and the provision of geodetic and geophysical parameters such as Earth Rotation Parameters (ERP) and geocenter (GCC) coordinates. In GNSS data processing ambiguity resolution (AR) is critical to achieve high-precision estimates. Due to the uncalibrated phase delay (UPD), currently most International GNSS Service (IGS) Analysis Centers (ACs) adopt the double-differenced (DD) ambiguity resolution strategy, which eliminates UPD by between-satellite and between-station differencing. Undifferenced (UD) ambiguity resolution, which recovers the integer characteristics of the UD ambiguities by directly estimating the UPD, was originally developed for Precise Point Positioning and nowadays is also applied to network processing, for example for Precise Orbit Determination (POD). In this study, we conducted a comparative study on the UD and DD ambiguity resolution for GNSS POD data processing. We demonstrated that the UD strategy significantly improves the solution compared to the DD solutions. The GPS orbit precision is improved by 20%, 12%, and 5% in the along, cross, and radial component, respectively. Moreover, the ERP are significantly improved, and the agreement with the IGS final products is improved by 28% and 23% for the offsets of x-pole and y-pole, respectively, and by 23%, and 17% for the corresponding rates. Additionally, the repeatability of station coordinates and GCC coordinates is also slightly improved. More important, we confirmed that the two strategies are theoretically equivalent and the outperformance of UD strategy could be explained by its strong robustness to wrong-fixings and its capability to fix the most UD ambiguities, while wrong-fixings and missing fixings are hardly avoidable in the DD strategy due to the requirement of forming DD-ambiguities.
A wavelet-based workflow for cyclostratigraphic studies using the WaverideR R package
Authors: Arts Michiel , Da Silva Anne-Christine
Published: February 2023

Cyclostratigraphic studies are based on accurately identifying astronomical cycles in the geological record. In excellent geological records, observed cycles can be directly coupled to their corresponding astronomical cycles. In more complex records spectral analysis techniques are needed to identify astronomical cycles. Most cyclostratigraphic studies utilise spectral analysis techniques based on the Fast Fourier transform (FFT). FFT-based spectral analysis techniques are excellent in identifying orbital cycles when the signal is stationary (e.g., the sedimentation rate is constant). To track changes in the sedimentation rate, a sliding window-based FFT analysis is often implemented, resulting in a frequency versus depth/time plot highlighting frequency changes and/or changes in the sedimentation rate. Windowed FFT-based techniques have one significant drawback: the window size has a fixed length, which limits the frequency range that can be analysed. The Continuous Wavelet Transform (CWT) avoids this drawback because the wavelet scales proportionally to the length of the analysed period. Current wavelet-based software/packages lack the features needed to complete a cyclostratigraphic study; therefore, the WaverideR R package (https://stratigraphy.eu/downloads) was developed, which contains all the essential functions required to do a CWT-based cyclostratigraphic analysis. To highlight the functionalities and versatility of the functions of the WaverideR R package, set functions are applied to three records; the Holocene Total Solar Irradiance (TSI) record, the Miocene ODP 926 greyscale record, and the Devonian Sullivan core magnetic susceptibility record.  The TSI record analysis highlights the WaverideR package's ability to change the omega (cycles within a wavelet) and extract cycles from the wavelet directly. The study of the Miocene ODP 926 greyscale shows how the WaverideR package can directly extract astronomical cycles in the depth domain and anchor this astronomical cycle to the astronomical solution. The analysis of the Devonian Sullivan core magnetic susceptibility record shows how the WaverideR package can trace the 405 kyr eccentricity cycle in a wavelet spectrum and create a floating age model, identify cycles in the time domain and then extract those cycles and the features of those extracted cycles such as its spectral power and its amplitude from the wavelet spectra. 
Gravity Estimation from Satellite-Satellite Tracking using Total Variation Regularization
Authors: Jacob Geethu , Bettadpur Srinivas
Published: February 2023

The problem of gravity estimation from satellite-satellite tracking measurements is fundamentally ill-posed due to upward continuation, which results in poor observability of the high-frequency components of the potential. Additionally, the ground track orientation and orbital resonance introduce poor observability along certain directions and spectral bands of the solution. Consequently, the gravity estimates obtained by direct inversion exhibit non-physical noise features. Regularization schemes are employed in the solution of ill-posed problems, wherein pseudo-information is added to the optimization cost function to stabilize the inversion. The preferred regularization scheme for spaceborne gravity estimation has been L2-Tikhonov regularization with a heuristic constraint matrix.Regularization schemes based on the spatial gradient of the solution field, such as H1 and Total Variation (TV), produce a penalty that naturally increases with frequency. Thus, they are effective in countering the ill-posedness due to poor observability of higher frequencies. Additionally, the TV penalty has the unique feature of promoting sharp edges, which could limit signal leakage in the solution. We previously reported results from the application of gradient regularization schemes as post-processing to the GRACE/GRACE-FO problem, as well as preliminary results from the application of these techniques to the full problem.Here, we present the time series of solutions obtained by the application of gradient regularization methods to the full GRACE/GRACE-FO gravity estimation problem. The edge-preserving nature of the TV penalty facilitates recovery of sharp edges and signal localization in the solution, without the need for explicit spatial constraints. Additionally, we present results from the application of higher order generalizations of the TV penalty (Total Generalized Variation), which allows for recovery of sharp edges while limiting the undesirable peak-flattening effect induced by the TV penalty.
Direct Measurements of Evapotranspiration can help steer irrigation forecasts
Authors: Pandithage Ruwin , Jaques Johan
Published: February 2023

Direct measurements of Evapotranspiration (ET) in combination with measured or modelled ETp, provide a direct insight into a plant- and location specific water balance and eventual subsequent drought stress that crop has been experiencing. Using further input from measured ETp and/or ETo, completed with the output of numerical weather prediction models for ETp and precipitation quantities (either deterministic- or ensemble prediction system values), a reference crop irrigation forecasts can be generated for the next days. Applying additionally crop specific water needs to the input variables, a crop- and phenological stage- specific forecast for irrigation can be issued for that particular location.
Swift generator for 3D magnetohydrodynamic turbulence
Authors: Maci Daniela , Keppens Rony , Bacchini Fabio
Published: February 2023

Turbulent states of motion are almost unavoidable in fluids, gases, and plasmas. The ubiquitous presence of turbulence largely contributes to the central role that its study holds in many research fields. This work focuses on space and astrophysical plasmas, where magnetohydrodynamic turbulence is observed nearly everywhere. However, it builds on an issue that is shared by all turbulence-related field of studies: direct numerical simulations (DNS), required to verify turbulent states properties such as scaling law behaviors, require substantial computing resources.The presentation will introduce the audience to BxC[1], an analytic generator of realistic-looking turbulent magnetic fields, that computes 3D O(10003 grid points) solenoidal vector fields in minutes to hours on desktops. The model is inspired by recent developments in 3D incompressible fluid turbulence theory: intermittent, multifractal random fields are generated through non-linear transformations of a Gaussian white noise vector, combined to specifically designed geometrical constructions. Furthermore, the model is implemented starting from a modified Biot-Savart law, which allows for a clear interpretation of the BxC parameters.The turbulent magnetic field realized with BxC is then compared and validated against a much more computationally expensive DNS in terms of: (i) characteristic sheet-like structures of current density, (ii) volume-filling aspects across current intensity, (iii) power-spectral behaviour, (iv) probability distribution functions of increments for magnetic field and current density, structure functions, spectra of exponents, and (v) partial variance of increments. [1] Durrive, J.-B., Changmai, M., Keppens, R., Lesaffre, P., Maci, D., and Momferatos, G. (2022). Swift generator for three-dimensional magnetohydrodynamic turbulence. Phys. Rev. E, 106:025307
Opening the ‘black-box’ of climate risk assessments for real estate portfolios: lessons from The Netherlands
Authors: Kelder Timo , Goosen Hasse , Kadijk Jan , van Veldhoven Felix
Published: February 2023

The real estate sector is in the spotlight of EU regulations given its high environmental impact. Technical screening criteria were established, and organisations now need to align with the EU Taxonomy. As these organisations often lack climate change expertise, a large number of (often commercial) providers have developed different methods to support the real estate sector in assessing physical climate risk. This created the challenge of transparency, the lack of which limits trust and the ability to improve, compare and combine the results of different assessments: the ‘black-box’ approaches.In an attempt to ‘open the black box’ in the Netherlands, a large consortium of financial institutions, knowledge institutes, consultants and governments has developed a ‘Framework for Climate Adaptive Buildings’. We will present this framework with the aim of laying the foundations for a common language and a level playing field for climate adaptation in the built environment. The framework combines an estimation of climate threats to the surroundings of buildings with the vulnerability of the building itself to identify appropriate adaptation measures. We will discuss the process of developing this framework, which featured extensive end-user involvement and co-production. Much emphasis was placed on the comparability and reproducibility of the resulting climate risk assessments by referring to freely available, national-level climate data, with transparency about the underlying methods.Climate service providers can use the framework as a starting point and build upon it with their existing approaches. As such, the framework ensures a level playing field for climate risk assessments for the real estate sector for Dutch assets. Upscaling the framework to the wider EU region is of great interest, as many investors have assets in multiple countries. A large challenge is the trade-off between comparable EU-wide datasets or less comparable but more reliable local data sources. We will discuss this challenge based on our experiences through the H2020 REACHOUT project before concluding with the takeaways from both the Dutch Framework for Climate Adaptive Buildings and the REACHOUT project.
Observation and source apportionment of atmospheric alkaline gases in urban Beijing, China
Authors: Zheng Jun , Zhu Shengnan , Yang Dongsen , Ma Yan
Published: February 2023

Atmospheric alkaline gases, including NH3 and amines, have been demonstrated to play crucial roles in atmospheric chemical processes, from enhancing atmospheric nucleation to promoting secondary particulate matter formation. It has been suggested that new particle formation can contribute significantly to haze formation in Beijing and other megacities in China. Although NH3 and amines have been ubiquitously detected in the atmosphere, little is known about the specific source profiles and the corresponding source contributions. It is well accepted that agriculture-related emissions dominate the global NH3 budget in the atmosphere. However, several recent field studies demonstrated that non-agricultural emissions are the primary NH3 sources in many urban areas in China. Therefore, atmospheric models based on emission inventories concentrated on agricultural emissions may not realistically simulate the atmospheric environment, particularly in the populated megacities of China. Recently, NH3, amines, amides, and imines emission characteristics of motor vehicles have been determined explicitly through in situ roadside measurements. However, the emission features from many other anthropogenic activities are still unknown. In this study, based on constrained SoFi-PMF analysis, we have investigated the specific impacts of motor vehicle emissions on NH3 and other alkaline gases in urban Beijing. It was found that motor vehicles can contribute a predominant portion of amines in the urban environment, particularly during daytime. Hence, reducing on-road vehicular emissions can decrease primary emissions of criteria air pollutants (such as NOx, SO2, and PM2.5) and suppress secondary aerosol formation. Although the PMF-based source apportionment analysis may be subjective to individual bias, it provides a valuable opportunity to explore other non-vehicular sources. The septic system in the urban area is recognized as a significant contributor to background NH3 and amines in urban Beijing. Motor vehicle emissions usually show less seasonal variability. Intense demands for central heating, power generation, and biofuel usage in suburban areas may play a significant role in wintertime haze formation. These emission activities, however, may highly depend on environmental conditions, such as temperature and humidity. Further investigations of the underlying releasing mechanisms and emission intensities are critically needed.
Mapping the impact of levee failure on flood risks: A Toronto case study
Authors: Mainguenaud Florence , Khan Usman T , Peyras Laurent , Carvajal Claudio , Beullac Bruno , Sharma Jitendra
Published: February 2023

Urban areas are frequently built along rivers and earthen levees are commonly used to protect areas from fluvial floods. Levees are designed to protect assets from flooding, however, they deteriorate over time. Maintenance checks are required to maintain their efficacy but even in good condition, a levee structure may fail during a flood, hence flood risk assessments in fluvial areas require an investigation of levee failures, e.g. by overtopping, erosion, or sliding. In this research, we investigate the failure probability due to backward erosion of an adapted levee in the Etobicoke Creek watershed, in Toronto, Canada. The study proposes an adapted levee as the residential area is often flooded. Backward erosion is the most probable and challenging failure mechanism for our case study based on the levee shape and soil type. For this probabilistic study, the levee was modelled using GeoStudio, which produces seepage analysis from geotechnical and hydrological parameters. The seepage analysis provides hydraulic gradients from which we determine the failure probability of backward erosion based on a critical hydraulic gradient value. To obtain the flood hazard, we use a steady flow hydraulic model (HEC-RAS) to simulate the 350-years return period flow through the River. We compare two backward failure scenarios: one with a levee breach and one without, to better understand how failure of the levee will impact flood risks, and therefore, highlighting the importance of on-going levee maintenance. To obtain flood risk maps, the flood hazard (i.e., flood extent) is combined with flood exposure. The flood exposure includes land-use type (residential, commercial, etc.) and demographic information. Flood hazard and exposure data are combined using ArcGIS. The flood hazard and exposure rasters are reclassified in a new scale to determine flood risk. We then overlay the rasters to determine the spatial distribution of flood risk for both scenarios. We compare the resulting flood risk maps and calculate the change in flood risks for the area protected by the levee. Accounting for potential failure of infrastructure in flood risk mapping results in more accurate risk estimations. We also demonstrate the positive impact of the levee.
Topographic signatures and statistics of different tectonic regimes and application to terrestrial planets
Authors: Louro Lourenço Diogo , Manga Michael , Tackley Paul
Published: February 2023

A tectonic regime is the surface expression of interior dynamics in a planet. With the help of numerical models, different tectonic regimes have been proposed. Some of these are: (1) plate tectonics or mobile lid, (2) stagnant lid, (3) episodic lid, (4) plutonic-squishy lid, (5) and heat pipe (e.g., Lourenço et al., G3 2020). Over time, a tectonic regime shapes the surface of a planet, including its surface topography. Using the numerical models, we can compute the topographies associated with different tectonic regimes including spatial and temporal measures of variations. In this study, we compute statistics for the topography formed by different tectonic regimes in numerical models and compare with the statistics of observed topography of different terrestrial planets, with the aim of linking a planet to a tectonic regime at the present-day. Venus’ topography is better matched by topography distributions obtained for plutonic-squishy lid models than those for stagnant- or episodic-lid models, while Earth’s oceanic topography is best matched by mobile-lid models.