bluuebunny/crossref_metadata_2025 huggingface dataset:
Eight years of temporal gravity changes observed by the Swarm satellites
Authors: Teixeira da Encarnacao Joao , Arnold Daniel , Bezdek Ales , Dahle Christoph , Guo Junyi , van den IJssel Jose , Jaeggi Adrian , Klokocnik Jaroslav , Krauss Sandro , Mayer-Guerr Torsten , Meyer Ulrich , Sebera Josef , Shum Ck , Visser Pieter , Zhang Yu
Published: March 2022

The GPS data collected by the Swarm satellites form the basis for monthly global gravity field models that are complete and uninterrupted since late 2013, thus already covering a period of eight years. A nice aspect is that this time series covers the gap between the GRACE and GRACE-FO missions, as well as any other short gaps in their time series, with a spatial resolution of roughly 1500 km.

The Astronomical Institute of the University of Bern, the Astronomical Institute of the Czech Academy of Sciences, the Delft University of Technology, the Institute of Geodesy of the Graz University of Technology, and the School of Earth Sciences of the Ohio State University have teamed up to routinely provide these monthly models, with the support of the European Space Agency and the International Combination Servicefor Time-variable Gravity Fields (COST-G). The models are published every 3 months at ESA’s Swarm Data Access server (https://swarm-diss.eo.esa.int) as well at the International Centre for Global Earth Models (http://icgem.gfz-potsdam.de/series/02_COST-G/Swarm). Our gravity field models do not rely on any other source of gravimetric data nor any a priori information in for example the form of temporal and spatial correlations. The strength of our approach is that each institute exploits different gravity inversion strategies, thus producing independent solutions, which are combined at the solution level using weights derived with Variance Component Estimation.

Considering a reference parametric model derived from GRACE/GRACE-FO data, our models traditionally agree at the level of roughly 4 cm Equivalent Water Height (EWH). Since early 2020, developments in the processing of the kinematic orbits have improved this figure to 3 cm. A particularity of the Swarm gravity field models is that the deep ocean areas are ~30-50% noisier than land areas, with the underlying reason yet unknown. At the spatial resolution of Swarm, the time series of large water storage basins show a temporal correlation of 0.75 when compared with GRACE models, and their trends agree within 1 cm/year in terms of EWH.
A way-out from the maze of middle Miocene Sphaeroidinellopsis (planktonic foraminifera)
Authors: Fabbrini Alessio , Zaminiga Ilaria , Ezard Thomas , Wade Bridget
Published: March 2022

The taxonomy and phylogeny of the Miocene to Recent genus Sphaeroidinellopsis have been documented in previous studies, but the evolution of this lineage remains unclear. Some authors debated this genus in the past, choosing a variety of parameters to discriminate between morphospecies. Here we present new high detail analyses of specimens from Ocean Drilling Program (ODP) Site 925 (Ceara Rise, western equatorial Atlantic) and ODP Site 959 (Deep Ivorian Basin, eastern equatorial Atlantic). We present transitional individuals Sphaeroidinellopsis disjuncta–Sphaeroidinellopsis kochi, a speciation event never described before. These transitional specimens are characterized by extreme morphological features such as elongated and sac-like final chambers, requiring amendments to the current classification and taxonomy of these morphospecies. An alternative hypothesis is presented to assess these new observations within the evolutionary mosaic of Sphaeroidinellopsis.
What is the flux of low energy electron precipitation in the lower thermosphere? 
Authors: Eide Haakon Dahl , Tyssøy Hilde Nesse , Tesema Fasil , Babu Eldho Midhun
Published: March 2022

Energetic particle precipitation (EPP) into the atmosphere, lead to chemical reactions producing NOx gases. Auroral electrons deposit their energy at altitudes throughout the upper mesosphere and lower thermosphere. During the winter the EPP-produced NOx gases can survive for months and be transported down to the stratosphere, where it can destroy ozone through catalytic reactions. Studies comparing the NO density estimated by chemistry climate models and observations suggest that the estimation of NO-production by auroral forcing is overestimated during quiet times and underestimated during active time. This study provides an intercomparison of different auroral forcing estimates. We compare fluxes from the Total energy detector (TED) onboard the NOAA Polar Orbiting Environmental Satellites (POES) and Meteorological Operational satellite (MetOp), sensor for precipitating particles (SSJ) from Defense Meteorological spacecraft Program (DMSP), alongside a Kp-driven auroral model. The data over a full year was sorted by the daily Kp and evaluated as function of geomagnetic latitude and magnetic local time. Discrepancies are evaluated in respect to geographical bias, as well as geometric factors of the satellites. Furthermore, the observations are compared to the Kp-driven auroral model.
Mapping Arctic sea ice surface roughness with Multi-angle Imaging Spectro-radiometer.
Authors: Johnson Thomas , Tsamados Michel , Muller Jan-Peter , Stroeve Julienne
Published: March 2022

Surface roughness is a crucial parameter in climate and oceanographic studies, constraining momentum transfer between the atmosphere and ocean, providing preconditioning for summer melt pond extent, while also closely related to ice age and thickness. At a local scale, roughness in the form of ridges, hummocks, rafted ice can slow down and hinder safe transport on the ice as well as be a hazard for ice strengthened vessels and structures. High resolution roughness estimates from airborne laser measurements are limited in spatial and temporal coverage while pan-Arctic satellite roughness have remained elusive and do not extend over multi-decadal time-scales. The MISR (Multi-angle Imaging SpectroRadiometer) instrument acquires optical imagery from nine near-simultaneous camera view zenith angles sampling specular anisotropy, since 1999. Extending on previous work to model sea ice surface roughness from MISR angular reflectance signatures, a training dataset of cloud-free pixels and coincident roughness from coincident operation IceBridge (OIB) airborne laser data is generated. Surface roughness, defined as the standard deviation of the within-pixel lidar elevations to a best-fit plane, is modelled using several techniques and Support Vector Regression with a Radial Basis Function kernel selected. Hyperparameters are tuned using grid optimisation, model performance is assessed using blocked k-fold cross-validation. We present a derived sea ice roughness product at 1.1km resolution over the period of operation (April 2000 – 2020) and a corresponding time series analysis. To demonstrate the validity of the derived product, we first evaluate our roughness product against independent LiDAR characterisations of surface roughness consistent with our training data. We also evaluate our derived roughness product with known proxies of surface roughness on a pan-Arctic basis (AWISMOS CS2-SMOS sea ice thickness.) Both our instantaneous swaths and pan-Arctic monthly mosaics show considerable capacity in detecting newly formed smooth ice from polynyas, and detailed surface features such as ridges and leads.
RadHawk: a smart UAV for hunting radioactivity
Authors: Albéri Matteo , Cabras Daniele , Chiarelli Enrico , Cicala Luca , Colonna Tommaso , Corbo Matteo , De Cesare Mario , Ferraro Antonio , Givoletti Jacopo , Guastaldi Enrico , Maino Andrea , Mantovani Fabio , Morichi Massimo , Montuschi Michele , Raptis Kassandra Giulia Cristina , Semenza Filippo , Strati Virginia , Vivaldi Franco
Published: March 2022

Vertical take-off and landing Unmanned Aerial Vehicles (UAVs) for Gamma-Ray Surveys (GRS) provide a cost-effective and timely approach tool for environmental radioactivity mapping. The UAV technique combines the advantages of ground and airborne measurements:  there is no need for an airport for take-off and landing, and high spatial resolution surveys can also be performed in dangerous areas without endangering the operators.

The main limitation of existing UAVs for GRS is the lack of software and hardware integration between avionics systems and radiation detectors. RadHawk fills this gap with an advanced mechanical, electronic, and software connection between a specifically developed quadcopter and a digital Multi-Channel Analyzer GammaStream (GS). The GS is coupled with a 2” CeBr3 scintillator having spectral energy resolution ~60% better than that of a NaI for 137C detection. Communication between the GS onboard microcomputer and the drone’s autopilot Pixhawk is achieved through a custom protocol which allows sharing telemetry updates and executing commands.

The best spatial resolution of radiometric data is achieved through a list mode real-time processing that generates, with optimized acquisition time, energy calibrated georeferenced gamma spectra. A radio frequency transceiver module sends data to a control station, where the user can easily control the flight path and check the artificial radionuclides warning for real-time identifying of hotspots.

A post-processing algorithm based on a Full Spectrum Analysis – Maximum Likelihood Estimation was developed to enhance the identification capability of anthropogenic radionuclides and to produce maps of the K, Th and U abundances of the investigated areas.
Benchmarking Automatically Identified Model Structures with a Large Model Ensemble
Authors: Spieler Diana , Lei Kan , Schütze Niels
Published: March 2022

Recent studies have introduced methods to simultaneously calibrate model structure choices and parameter values to identify an appropriate (conceptual) model structure for a given catchment. This can be done through mixed-integer optimization to identify the graph structure that links dominant flow processes (Spieler et al., 2020) or, likewise, by continuous optimization of weights when blending multiple flux equations to describe flow processes within a model (Chlumsky et al., 2021). Here, we use the combination of the mixed-integer optimization algorithm DDS and the modular modelling framework RAVEN and refer to it as Automatic Model Structure Identification (AMSI) framework.

This study validates the AMSI framework by comparing the performance of the identified AMSI model structures to two different benchmark ensembles. The first ensemble consists of the best model structures from the brute force calibration of all possible structures included in the AMSI model space (7488+). The second ensemble consists of 35+ MARRMoT structures representing a structurally more divers set of models than currently implemented in the AMSI framework. These structures stem from the MARRMoT Toolbox introduced by Knoben et al. (2019) providing established conceptual model structures based on hydrologic literature.

We analyze if the model structure(s) AMSI identifies are identical to the best performing structures of the brute force calibration and comparable in their performance to the MARRMoT ensemble. We can conclude that model structures identified with the AMSI framework can compete with the structurally more divers MARRMoT ensemble. In fact, we were surprised to see how well we do with a simple two storage structure over the 12 tested MOPEX catchments (Duan et al.,2006). We aim to discuss several emerging questions, such as the selection of a robust model structure, Equifinality in model structures, and the role of structural complexity.

 

Spieler et al. (2020). https://doi.org/10.1029/2019WR027009

Chlumsky et al. (2021). https://doi.org/10.1029/2020WR029229

Knoben et al. (2019). https://doi.org/10.5194/gmd-12-2463-2019

Duan et al. (2006). https://doi.org/10.1016/j.jhydrol.2005.07.031
How are snowmelt rates changing across climates? Insights from a new Northern Hemisphere SWE dataset
Authors: Fontrodona-Bach Adrià , Larsen Josh , Woods Ross , Schaefli Bettina , Teuling Ryan
Published: March 2022

Although warming temperatures should intuitively lead to faster snowmelt, some studies suggest that melt rates might be slower in a warming world. This assumes that typically deep snowpacks are thinning and become isothermal earlier in the season when less solar radiation is available for melt. Investigating these changing snow dynamics is challenged by a lack of observations on water content of the snowpack, the Snow Water Equivalent (SWE). However, high quality observations of snow depth are generally more available in both space and time, even at higher elevations. Here we present a new dataset of historical SWE time series over the Northern Hemisphere, including a wide variety of climates. These time series are obtained converting historical ground-based snow depth time series to SWE by using the DeltaSNOW model. For the conversion to work over a range of climates, we apply a regional calibration of model parameters based on climatological data and provide model performance and uncertainty estimates. For >2.000 sites characterised by seasonal snow, we investigate changes in total snow accumulation, timing of snowmelt and melt rates for the period 1980-2020. Large decreases in total melt and earlier melt timing are widely observed. However, trends in snowmelt rates are generally weak and spatially inhomogeneous. Slower snowmelt in a warmer world occurs mostly on deep snowpacks that have been heavily depleted and where the number of days with melt has not significantly changed, making melt rates slower. However, both faster and slower melt are observed on sites where both the amount of melt and number of melt days have decreased. We provide an analysis of the causes for the spatial and temporal variability in trends. We find that trends can differ depending on the definition of melt rate and peak SWE, and that the drivers of the trends differ over different climates. Strong warming generates large melt events during the late accumulation season, challenging the commonly used definition of peak SWE and making it harder to compare the snowmelt dynamics of the past and the current climate. We note that focusing on melt rate change might mask important effects on melt timing and magnitude, because a proportional reduction in total melt and number of melt days can lead to no change in melt rate.
Arctic Amplification during the Last Glacial Inception due to a delayed response in sea ice and SST
Authors: Xu Shan , Krebs-kanzow Uta , Lohnmann Gerrit
Published: March 2022

The last glacial inception marks the transition from an interglacial warm climate to a glacial period with extensive northern Hemispheric ice sheets and with a globally colder climate.  This transition is generally believed to be initiated by the decreasing summer insolation in the Northern Hemisphere, and amplified and accelerated by strong positive feedbacks that transform the seasonal and latitudinal forcing to stimulate the growth of Northern hemisphere ice sheets and to eventually trigger a fundamental global response. The internal role of these feedbacks is yet not fully clear. Here, we analyzed climate simulations under the radiative forcing of 115 thousand years BP  in comparison to a respective simulation of the preindustrial period. To use a consistent definition of the seasons during 115ka and the preindustrial, we convert the model output to an angular calendar. Our study reveals a prominent role of the sea ice feedback to amplify the annual mean response with continental albedo and vegetation feedback also contributing.  
Tsunami Ready Programme in NEAM region: strategies, responsibilities and further advancements to protect communities from tsunamis
Authors: Valbonesi Cecilia
Published: March 2022

One of the most critical part of tsunami warning systems is the so-called “last mile”, i.e., informing promptly residents and tourists about a possible impending inundation.

In Italy, one of the most recent activities to reach this goal is the implementation of the Tsunami Ready (TR) Program, developed under the aegis of UNESCO and achieved in synergy between INGV, ISPRA and the Italian Civil Protection Department (the three components of the Italian Tsunami Warning System - SiAM).

In 2020, the path towards the TR recognition has started in three Italian pilot municipalities: Minturno, Palmi, Marzamemi. The response of local authorities has been enthusiastic in all three cases, despite numerous bureaucratic obstacles to involvement and membership.

Italy as a NEAM member aims to reach the goal of 100% of communities at risk of tsunami prepared for and resilient to tsunamis by 2030 through the implementation of the UNESCO/IOC Tsunami Ready Programme.

Several developments are going on because all participants are aware that TR is a virtuous model for dealing with tsunami risk, with numerous implications in terms of education and responsibilities for the harmful consequences of a tsunami.

First of all, the direct involvement of citizens in the education and information process represents a significant step change of TR. It is achieved through the participation of citizens’ representatives in the TR Local Board, which is responsible for monitoring the development of procedures and certifying that a suite of 12 target parameters identified in the TR guidelines have been accomplished.

It is important to remind that the recognition as Tsunami Ready community must be also approved by the National TR Board and by the UNESCO ICG.

Secondly, the existence of internationally accredited guidelines (IOC UNESCO n. 74 and its ongoing updates) represents a reliable parameter for determining the behavior to be adopted by public decision-makers.  In case of harmful events, the compliance with these parameters can contribute to mitigating the (possible) criminal reproach against civil protection officers charged in risk management.
Responses of gravel-bed river networks to periodic environmental change
Authors: McNab Fergus , Schildgen Taylor , Turowski Jens , Wickert Andrew
Published: March 2022

Environmental conditions exert a primary influence on surface processes such as the production, transport and deposition of sediment. An implication of this behaviour is that sedimentary deposits may record information about past environmental change and its influence on landscape evolution. Extracting this information requires an understanding of the ways in which material is transported from upstream source regions to downstream sedimentary sinks. As such, many recent studies have explored responses of alluvial rivers, the principal agents of sediment transport, to variations in sediment and water supply. In general, these studies have focused on resulting variations in sediment delivery to downstream sinks. However, changing sediment and water supply also results in changes in slope along alluvial rivers, accommodated by aggradation and incision of the valley floor. Cycles of aggradation and incision appear to be recorded by fluvial landforms such as cut-and-fill terraces at many sites around the world. These records may therefore provide an important yet underutilised link between climatic change and resulting variation in sediment production upstream, and the stratigraphic record downstream.

Here, we investigate responses of alluvial rivers to environmental change, with particular focus on resulting variations in channel elevation that could be recorded as fluvial terraces. We employ a recently developed model describing the long-profile evolution of gravel-bed rivers that takes a non-linear diffusive form. This model is defined in terms of measurable properties of river valleys, so should be readily applicable to real settings. For the simple case in which properties such as water discharge and valley width do not vary downstream, we obtain approximate analytical solutions to the diffusive equation that describe resulting variations in the river long profile and bedload sediment discharge. When periodic variation in sediment or water supply is imposed, periodic aggradation and incision occurs that is damped and phase shifted with respect to the imposed variation. Depending on whether sediment or water supply is varied, variation bedload sediment discharge can be damped or amplified. The extent to which signals are modified depends on the distance down valley and the relationship between the forcing period and the valley’s intrinsic response time. Using numerical models, we also explore more complex cases in which water discharge is supplied along the valley, and describe a method for estimating the response time of gravel-bed river networks. Finally, we compare our predictions with observations from a selection of well-studied terrace sites. Our results highlight which kinds and timescales of past environmental change could be represented in fluvial terrace and stratigraphic records and will facilitate improved interpretation of those records.
Automated detection and classification of synoptic scale fronts from atmospheric data grids
Authors: Niebler Stefan , Spichtinger Peter , Miltenberger Annette , Schmidt Bertil
Published: March 2022

Automatic determination of fronts from atmospheric data is an important task for weather prediction as well as for research of synoptic scale phenomena. We developed a deep neural network to detect and classify fronts from multi-level ERA5 reanalysis data. Model training and prediction is evaluated using two different regions covering Europe and North America with data from two weather services. Due to a label deformation step performed during training we are able to directly generate frontal lines with no further thinning during post processing. Our network compares well against the weather service labels with a Critical Success Index higher than 66.9% and a Object Detection Rate of more than 77.3%. Additionally the frontal climatologies generated from our networks ouput are highly correlated (greater than 77.2%) to climatologies created from weather service data. Evaluation of cross sections of our detection results provide further insight in the characteristics of our predicted fronts and show that our networks classification is physically plausible.
Can runoff event types explain some scatter in nitrate C-Q relationships?
Authors: Saavedra Felipe , Musolff Andreas , Von Freyberg Jana , Merz Ralf , Basso Stefano , Tarasova Larisa
Published: March 2022

Nitrate contamination of rivers from agricultural sources, is a challenging problem for water quality management. The relationship between solute concentrations and streamflow rates (C-Q) observed at catchment outlets provide useful information on hydrological functioning and biogeochemical transformations at catchment scale. Nevertheless, nitrate C-Q relationships (linear regression in log space) often exhibit a considerable scatter. 

 

During runoff events, different nitrate transport paths within the catchment might be activated, generating a variety of responses in nitrate concentration. We hypothesize that the differences in characteristics of runoff events, such as different portions of rainfall and snowmelt contributions or antecedent wetness states, can explain some observed scatter in long-term C-Q relationships of nitrate.

 

To investigate this hypothesis, we analyzed low frequency nitrate data from 184 German catchments during different types of runoff events and quantified the deviations of the C-Q relationship for different event types. First, we computed the long-term C-Q relationships for each study catchment. Then, we attributed each nitrate grab sample to the corresponding runoff event type or non-event conditions, based on the nature of the inducing event and the antecedent wetness states of the catchments. Finally, we quantified the deviations from the long-term C-Q relationship.

 

We found pronounced deviations of different event types from the long-term C-Q relationships in most of the study catchments. During snow-impacted events, deviations are normally positive, indicating higher nitrate concentrations than the long-term C-Q relationships. On the other hand, deviations of rainfall events during dry antecedent conditions are mostly negative. Moreover, for rainfall events during wet antecedent conditions, we do not find persistent deviations from long-term C-Q patterns. Pronounced differences in event runoff coefficients among different event types indicate that contrasting levels of hydrological connectivity are a key control of C-Q deviations among different event types.
Numerical modelling of Aquifer Thermal Energy Storage systems with Surface-Based Geologic modelling and Dynamic Mesh Optimisation
Authors: Regnier Geraldine , Salinas Pablo , Jacquemyn Carl , Jackson Matthew D.
Published: March 2022

Aquifer Thermal Energy Storage (ATES) has significant potential to provide large-scale seasonal cooling and heating in the built environment, offering a low-carbon alternative to fossil fuels. To deliver safe and sustainable ATES deployments, accurate numerical modelling tools must be used to predict flow and heat transport in the targeted aquifers. However, numerical simulation of ATES systems is very challenging, due to the associated high computational cost of capturing fluid flow and heat transport at a high resolution and importance of accurately modelling complex geological heterogeneity.

Here, we present a novel approach to simulate ATES, based on the use of surface-based geologic models (SBGM), a double control-volume finite element method, and unstructured tetrahedral meshes with dynamic mesh optimisation (DMO). Previous use of DMO for a range of porous media flow applications has allowed an important reduction in the cost of numerical simulations. DMO allows the resolution of the mesh to vary over time and space to satisfy a user-defined solution precision for selected fields, refining where the solution fields are complex and coarsening elsewhere. SBGM allows accurate representation of complex geological heterogeneity and efficient application of DMO, essential for accurate simulation of ATES without excessive computational cost. 

We demonstrate application of these methods in two low-temperature ATES scenarios: a homogeneous aquifer, and a heterogeneous fluvial aquifer containing meandering, channelised sandbodies separated by mudstones. For both cases, cold and warm water are injected alternatively over 6-month periods via a well doublet. We demonstrate that DMO reduces the required number of mesh elements by a factor of up to 22 and simulation time by a factor of up to 15, whilst maintaining the same accuracy as an equivalent fixed mesh. DMO significantly reduces the computational cost of ATES simulations in both homogeneous and heterogeneous aquifers. This offers significant advantages compared to conventional methods in assessing the impact of uncertain geologic heterogeneity on ATES operation and efficiency, and in optimising individual and multiple ATES deployments.
A new global nonlinear force-free coronal magnetic-field extrapolation code implemented on a Yin Yang grid.
Authors: Koumtzis Argyrios , Wiegelmann Thomas
Published: March 2022

The solar magnetic field dominates and structures the
coronal plasma and detailed insights are important to understand almost
all physical processes. While direct routine measurements
of the coronal magnetic field are not available, we have to extrapolate
the photospheric vector field measurements into the corona. To do so,
we developed a new code that performs state-of-the-art nonlinear force-free
magnetic field extrapolations in spherical geometry.
Our new implementation is based on an optimization principle and is
able to reconstruct the magnetic field in the entire corona, including
the polar regions.
Because of the nature of the finite-difference numerical scheme used in
the past, extrapolation close to polar regions was computationally
inefficient. In the current code, the so-called Yin Yang grid is used.
Both the speed and accuracy of the code is improved compared to previous
implementations. We tested our new code with a well known
semi-analytical model (Low and Lou solution). This new Yin and Yang
implementation is timely because
the Solar Orbiter mission is expected to provide reliable
vector magnetograms also in the polar regions within the following years.
Thus, this code can be used in the future when these synoptic magnetograms
are available to model the magnetic field of the solar corona for the entire
Sun including the polar regions.
Numerical investigation of scale influences on hydrodynamics and morphodynamics in a groyne field experiment
Authors: Glas Martin , Tritthart Michael , Sindelar Christine , Pessenlehner Sebastian , Buchinger Matthias , Lichtneger Petr , Habersack Helmut
Published: March 2022

Large physical experiments require - among others - scaling of channel geometry and sediments in order to fit to the available laboratory infrastructure. In this study, scaling effects were investigated with the help of a 3D numerical model (RSim-3D) and a coupled sediment transport model (iSed). Numerical experiments were based on the geometries of two physical scale experiments conducted at the University of Natural Resources and Life Sciences, Vienna, Austria. The large-scale experiments (1:1) were conducted in an open-air research channel with a channel width of 5 m. The small-scale experiments (1:5) were performed inside the Hydraulic Engineering Laboratory with a flume width of 1 m. The large-scale experiments (1:1) include sediments typical for the Austrian Danube River in the section East of Vienna and the small-scale experiments were conducted with a sediment size scaled by 1:5. Results from the physical scale experiments including a submerged and attracting groyne layout with varying groyne heights and water levels were used for calibration and validation of the numerical models. Numerical model results were analyzed with respect to scale influences. In contrast to the relatively small influence of scale on the determined normalized flow velocities, normalized turbulent kinetic energy was found to increase by up to 10 times within the outdoor research channel (1:1) in comparison to the smaller scale (1:5). Moreover, the scale effect was larger in the main stream than in the groyne field. Morphodynamic equilibrium was affected by the scale of the experiment, too, leading to enhanced erosions in the 1:1 scale experiment. The findings are relevant for future hydraulic engineering measures investigated by physical scale experiments and will help to avoid underestimations of hydrodynamic and morphodynamic processes induced by scale influences.
Messinian salt deformation offshore Algeria: the role of crustal tectonics and sedimentary load on the observed geometries
Authors: Travan Gaia , Gaullier Virginie , Vendeville Bruno C. , Déverchère Jacques
Published: March 2022

The Algerian margin (Western Mediterranean) reactivated in compression 8 My ago due to the convergence between Africa and Eurasia, and is nowadays subjected to a strain regime of several mm/y, resulting in destructive earthquakes as the M 6.8 Boumerdès event in 2003.

The MARADJA I seismic reflection data acquired in 2003 allowed to image in detail the Messinian Salinity Crisis Mobile Unit (mostly halite) and its brittle sedimentary overburden offshore Algiers. Particularly interesting in the area are the salt-related geometries and the presence of crustal tectonic structures -consequence of the compressional setting of this margin- that created an uplifted plateau offshore Algiers (Déverchère et al., 2005; Domzig et al., 2006). The comparison with the MARADJA II (2005) data offshore Béjaia allowed to better distinguish between the regional trends and the local peculiarities.

Together with the general analysis of the structures due to the salt tectonics, as well as the influence of crustal tectonics on salt deformation on the Algerian margin, this study is particularly focused on the geometry, position and triggering processes of a localized minibasins field, which started to form very early –possibly before the end of the Messinian Salinity Crisis- and is still active nowadays. This minibasins field position corresponds to both the external limit of a sedimentary body and the western limit of the previously mentioned uplifted plateau, raising the question of the relative influence of these two contributing factors in the formation of the minibasins. The analogue modelling contribution in this analysis is crucial.
A global climatology of the kinematical skeletons organising subtropical and tropical convergence zones
Authors: Martins Palma Perez Gabriel , Vidale Pier Luigi , Dacre Helen , Garcia-Franco Jorge
Published: March 2022

Large-scale mixing in the atmosphere redistributes moisture as organised bands or filaments. In some tropical and subtropical monsoon regions, a substantial part of rainfall happens under moisture and cloud bands commonly referred to as convergence zones. Recent regional studies have shown that such large-scale filaments or bands of moisture and rainfall form along or in the neighborhood of mixing features known as attracting ``Lagrangian Coherent Structure'' (LCSs) - material skeletons associated with strong attraction of air parcels. However, there are still no global climatologies to support more general conclusions about the spatiotemporal relationships between mixing and precipitation and the impact of large-scale mixing on monsoons. In this study, we investigate how mixing features determine the subseasonal and seasonal rainfall variability in tropical and subtropical regions around the globe. We characterise mixing by computing the Finite-time Lyapunov Exponent (FTLE), a measure of Lagrangian deformation among neighbouring parcels, on ERA5 reanalysis data between 1980 and 2009. Attracting LCSs are identified as ridges of the FLTE. We also employ diagnostic Eulerian variables such as mean sea level pressure and mass meridional streamfunction to associate mixing with general circulation features. On the seasonal scale, we show that the strength of mixing and the frequency of LCSs modulates rainfall under the African, American and Asian convergence zones and the ITCZ. On the subseasonal scale, we focus on the influence of the Madden-Julian oscillation and the North Atlantic oscillation on the mixing regime of the Atlantic and East Pacific; we show how these oscillations control horizontal mixing as to suppress or enhance precipitation variability over the American monsoons. This first long-term global climatology of mixing and LCSs quantifies the often overlooked role of Lagrangian kinematics on the hydrological cycle and provides a powerful process-based diagnostic to investigate mechanisms of rainfall variability that does not require region-specific considerations.
Developing a composite map of the Southeast and East Asia power systems
Authors: Ye Mengqi , Koks Elco , Ward Philip
Published: March 2022

Power systems provide vital services to modern society and are characterized by being highly interconnected in a variety of ways. The loss of power systems during weather extremes can potentially result in widespread, catastrophic impacts that may seriously disrupt socioeconomic activities. In practical terms, there are many interdependencies through which the indirect impacts of a major power outage ripple through social interactions and economic activities. However, both the scarcity of power infrastructure data and the complexity of power systems make it challenging to model these exact socioeconomic impacts of power outages in the aftermath of weather extremes. Unfortunately, power system datasets remain incomplete regarding most geographic areas, and the access to power infrastructure data in an open and standardized way is one of the main bottlenecks in risk modelling, especially for the medium and lower voltage distribution networks.

Limited spatial information on power infrastructure makes it difficult to respond to challenges in natural disasters and electricity reliability. Therefore, data collection of power systems should be the main priority in power infrastructure risk assessments. One of the possibilities to fill these data gaps is through the use of satellite imagery. However, automating the process of satellite imagery data classification and translating the extracted information into semantic classes, specifically for power infrastructure, has three main challenges: 1) images from different sources have complete different spatial resolutions, which makes it difficult to consistently identify power infrastructure; 2) most existing satellite imagery datasets are prepared for training classification models but do not include annotations for training detection models; 3) and there are few training datasets available for training power infrastructure detection models.

To fill this research gap, we will develop a state-of-the-art deep learning method to identify power infrastructure. Our methodology consists of two parts: 1) image segmentation for power lines by StackNetMTL, which helps to learn the interconnectivity within the system; 2) object detection for other power infrastructure (i.e., power plants, substations, and towers) by Mask R-CNN. This will provide us with a geospatial power infrastructure map of the Southeast and East Asia to support power systems risk assessment, for both the system itself and the potential societal impacts. This research will provide a consistent and reproducible way for machine-driven mapping of power infrastructure, paving the way for improved efforts in power system modelling and risk management in Southeast and East Asia.
Identification and Long-lasting Citability of Dynamic Data Queries on EMSO ERIC Harmonized Data
Authors: Rodero Ivan , Fornós Andreu , Bardaji Raul , Chiappini Stefano , Dañobeitia Juanjo
Published: March 2022

The European Multidisciplinary Seafloor and water-column Observatory (EMSO) European Research Infrastructure Consortium (ERIC) is a large-scale European Strategy Forum on Research Infrastructure (ESFRI) member with strategically placed sea observatories with the essential scientific objective of real-time, long-term monitoring of environmental processes related to the interaction between the geosphere, biosphere, and hydrosphere. EMSO ERIC collects, curates, and provides high-quality oceanographic measurements from surface to deep seafloor to assess long-term time series and oceanographic modeling. In addition, EMSO ERIC has developed a set of data services that harmonize its regional facilities’ data workflows, enhancing efficiency and productivity, supporting innovation, and enabling data- and knowledge-based discovery and decision-making. These services are developed in connection with the ESFRI cluster of Environmental Research Infrastructures (ENVRI) through the adoption of FAIR data principles (findability, accessibility, interoperability, and reusability) and supported by the ENVRI-FAIR H2020 project. 

EMSO ERIC’s efforts in adopting FAIR principles include the use of globally unique and resolvable persistent identifiers (PIDs) in alignment with the ENVRI-FAIR task forces. We present a service for the identification and long-lasting citability of dynamic data queries on harmonized data sets generated by EMSO ERIC users. The service is aligned with the Research Data Alliance (RDA) working group on data citation and has been integrated into the EMSO ERIC data portal. User-built queries on the data portal are served by the EMSO ERIC Application Programming Interface (API), which retrieves the user requested data and provides a Uniform Resource Identifier (URI) to the query, visualizations, and data sets in CSV and NetCDF formats. The data portal allows users to request a PID to the data query by providing mandatory and optional metadata information through an online form. The mandatory metadata consists of the description of the data and specific information about the creators, personal or organizational, including their identifiers and affiliations. The optional metadata consists of different types of titles and descriptions that the user finds compelling. The service provides a permalink to a web page maintained within the data portal with the PID reference, metadata information, and the URI to the data query. The web pages associated with PIDs also provide the option to request a Digital Object Identifier (DOI) if users are authorized via the EMSO ERIC Authorization and Authentication Infrastructure (AAI) system.
A vision and strategy to revamp ESM workflows at DKRZ
Authors: Peters-von Gehlen Karsten , Anders Ivonne , Heydebreck Daniel , Kadow Christopher , Ziemen Florian , Thiemann Hannes
Published: March 2022

The German Climate Computing Center (DKRZ) is an established topical IT service provider serving the needs of the German climate science community and their associated partners. At DKRZ, climate researchers have the means available to cover every aspect of the research life cycle, ranging from planning, model development and testing, model execution on the in-house HPC cluster (16 PFlops mainly CPU-based, 130 PB disk storage), data analysis (batch jobs, Jupyter, Freva), data publication and dissemination via the Earth System Grid Federation (ESGF) as well as long-term data preservation either at the project-level (little curation) or in the CoreTrustSeal certified World Data Center for Climate (WDCC) (extensive curation along the FAIR data principles). A plethora of user support services offered by domain-expert staff complement DKRZ’s portfolio.

 

With the new HPC system coming online in early 2022 and a number of funded and to-be funded projects exploiting the available computational resources for conducting e.g. global storm-resolving (grid spacing O(1-3km)) simulations on climatic timescales, the current interplay DKRZ’s services needs to be revisited to devise a unified workflow that will be able to handle the upcoming challenges. 

 

This is why the above mentioned projects will supply a significant amount of funds to conceive a framework to efficiently orchestrate the entire model development, model execution and data handling workflow at DKRZ in close collaboration with the climate science community.

 

In this contribution, we will detail our vision of a revamped and versatile ESM orchestration framework at DKRZ. Currently, this vision is based on having the orchestration performed by the Freva System (http://doi.org/10.5334/jors.253), in which users will be able to kick-off model compilation, compute and analysis jobs. Furthermore, Freva enables seamless provenance tracking of the entire workflow. Together with the implementation of data publication, long-term archiving and data dissemination workflows, the envisioned system provides a complete package of FAIR Digital Objects (FDOs) to researchers and allows for reproducibility, transparency and reduction of data redundancy. 
Kinetic Instabilities from Ion Beams and Differential Streaming in the Close-Sun Solar Wind: Hybrid Expanding Simulations
Authors: Matteini Lorenzo , Hellinger Petr , Landi Simone , Franci Luca , Tenerani Anna , Velli Marco
Published: March 2022

Parker Solar Probe observations in the inner heliosphere have demonstrated that non-thermal features in solar wind ion distributions are particularly enhanced and dominant in the close-Sun environment. Proton beams and large differential flows of alpha particles are ubiquitously observed, also in slow, though Alfvénic, streams, qualitatively at odds with typical observations at 1AU, where non-Maxwellian features are usually less apparent in the slow solar wind. All this reinforces the idea, also supported by past Helios and Ulysses explorations, that preferential ion heating and acceleration take place already in the Corona and signatures of the kinetic processes involved are gradually washed out during expansion. To explore further properties of ion differential streaming during expansion, as well as associated kinetic instabilities and their possible role in plasma heating, we perform expanding box hybrid simulations of a multi-species solar wind composed by proton core, beam and alpha particles, focussing on the role of wave-particle interactions in shaping distribution functions and controlling relative drifts. Radial trends and typical distributions found in simulations are then compared with PSP and Solar Orbiter observations in the inner Heliosphere.
Exploring the limits of in-situ U-Pb dating of metamorphic garnet
Authors: Beranoaguirre Aratz , Millonig Leo J. , Shu Qiao , Albert Richard , Marschall Horst R. , Gil Ibarguchi Jose Ignacio , Gerdes Axel
Published: March 2022

Recent advances in analytical techniques and instrumentation allow for the analysis of increasingly smaller sample volumes and lower concentrations. This development significantly expands the possibilities of in-situ geochronology, e.g., LA-MC-ICPMS. Minerals with low U (and Pb) contents such as garnet become the target of in-situ U-Pb geochronology since ages can potentially be obtained from single (sub-)mm-sized garnet grains in thin sections. In this contribution, we explore the current limits of in-situ U-Pb geochronology: what are the minimum concentrations from which an accurate and precise U-Pb age can be obtained?

For that purpose, we have analysed garnets from three different localities that were unsuccessfully analysed in the past using a single-collector sector-field Element XR instrument at FIERCE. These garnets have been re-analysed at FIERCE using a Neptune Plus MC-ICPMS coupled to a RESOLution-LR ArF Excimer laser. The analyses were performed in static mode measuring the masses 206Pb and 207Pb with Secondary Electron Multiplier (SEM) and 202Hg, 204Pb and 238U with the Multiple Ion Counters (MIC). With a spot diameter of 193 μm (round) and a fluence of 2 J/cm2 at 15 Hz, ca. 18 µm pit depth was ablated in 18s analysis time, resulting in a total of 2 µg of ablated material. This is more than 2,000 times less material compared to conventional isotope dilution analyses and 3,000 times less U than for a typical LA-ICPMS zircon analysis (20 µm spot). Although the analysed garnets typically have U contents below 10 ng/g, about 15–30 spots are commonly sufficient to define a regression line in the Tera-Wasserburg diagram, yielding a precision of typically <3 % for the lower intercept age. Challenges and details of the method will be discussed using samples of metamorphic garnet from Kaapvaal craton granulites and Eastern and Western Variscan eclogites.
In situ laser ablation Lu–Hf geochronology of garnet across the Western Gneiss Region, Norway
Authors: Tamblyn Renée , Hand Martin , Simpson Alexander , Gilbert Sarah , Wade Ben , Glorie Stijn
Published: March 2022

The development of in situ laser ablation Lu–Hf geochronology of apatite, xenotime and garnet has opened avenues to directly date mineral-forming geological processes. We demonstrate the first use of campaign-style in situ Lu–Hf geochronology of garnet across the high- to ultrahigh-pressure Western Gneiss Region in Norway. Mafic eclogites from this region have been the focus of much work, and were clearly formed during continental subduction during the Caledonian Orogeny. However, abundant quartzofeldspathic and pelitic lithologies record a more complex history, with some preserving polymetamorphic age data, and most containing no indication of high-pressure mineral assemblages formed during subduction. In this study, twenty metapelitic and felsic samples spanning 160 lateral kilometres across the Western Gneiss Region have been analysed using garnet Lu–Hf geochronology. The results reveal Caledonian ages for the majority of the garnets, suggesting that some quartzofeldspathic and metapelitic lithologies were reactive and grew garnet during high- to ultrahigh-pressure metamorphism. However, two ultrahigh-pressure eclogite locations, Verpeneset and Fjørtoft, preserve both Caledonian and Neoproterozoic-aged garnet. This polymetamorphism is recorded across different garnet grains within the same lithology, or within single polymetamorphic garnets. Despite significant uncertainties on some of the Lu–Hf geochronological ages, laser ablation Lu–Hf efficiently identifies the polymetamorphic history of parts of the Western Gneiss Region, illustrating the effectiveness of this novel analytical method for rapid mapping of metamorphic ages.